National Board Inspection Code (NBIC) - 2004 Edition

� � � � � �� ANSI/NB-23 Recognized Internationally National Board Inspection Code An American National Standard Note: Pages ii through xvi are not part of this American National Standard Library of Congress Catalog Card No. 52-44738 Printed in the United States of America All Rights Reserved © 2004 The National Board of Boiler and Pressure Vessel Inspectors Headquarters 1055 Crupper Avenue Columbus, Ohio 43229-1183 614.888.8320 614.847.1828 FAX Testing Laboratory 7437 Pingue Drive Worthington, Ohio 43085-1715 614.888.8320 614.848.3474 FAX Training and Conference Center 1065 Crupper Avenue Columbus, Ohio 43229-1183 614.888.8320 614.847.5542 FAX ii THE NATIONAL BOARD OF BOILER AND PRESSURE VESSEL INSPECTORS BOARD OF TRUSTEES OFFICERS D.A. Douin – Chairman R. Reetz – First Vice Chairman M. Mooney – Second Vice Chairman D.E. Tanner – Secretary-Treasurer MEMBERS AT LARGE R.R. Cate E.D. Eastman D.J. Jenkins Y. Nagpaul ADVISORY COMMITTEE W. Carey Representing organized labor W.D. Doty Representing the welding industry C.A. Neumann Representing boiler and pressure vessel users M.H. Jawad Representing boiler manufacturers G. McRae Representing pressure vessel manufacturers S. Rudnickas Representing authorized inspection agencies (insurance companies) E.J. Hoveke Representing National Board stamp holders iii COMMITTEE ON NATIONAL BOARD INSPECTION CODE R. Marvin State of Wasington C.S. Withers, Chair The National Board of Boiler and Pressure Vessel Inspectors C.A. Neumann Eastman Kodak Company R.V. Wielgoszinski, Vice Chair Hartford Steam Boiler Inspection and Insurance Co. of Connecticut M.R. Peterson State of Alaska R. Ferrell, Secretary The National Board of Boiler and Pressure Vessel Inspectors J.T. Pillow APComPower Inc. H.M. Richards Southern Company S.E. Bacon Conoco Phillips J. Richardson Consultant - Dresser Inc. D.A. Canonico Canonico & Associates J. Sekely Wayne Crouse, Inc. W. Carey International Brotherhood of Boilermakers R. Snyder Consultant R.R. Cate State of Louisiana H. Staehr Factory Mutual Global D. Cook State of California S. Staniszewski Jr. U.S. Department of Transportation W.D. Doty Doty and Associates, Inc. R.C. Sulzer Babcock & Wilcox P.D. Edwards Stone & Webster, Inc. H.N. Titer MIRANT Mid-Atlantic G.W. Galanes Midwest Generation EME, LLC M.J. Wheel State of Vermont P.C. Hackford State of Utah C. Hopkins Seattle Boiler Works iv NBIC Subcommittee on Overpressure Protection D.A. Bowers Jr., Chairman Velan Valve R.W. Donalson Anderson, Greenwood & Co. C.A. Neumann, Vice Chair Eastman Kodak Company F. Hart Flowserve US, Inc. J.F. Ball, P.E., Secretary The National Board of Boiler and Pressure Vessel Inspectors R.D. Marvin State of Washington T. Parks State of Texas M. Brodeur International Valve & Instr. Corporation D.K. Parrish FM Global S. Cammeresi Allied Valve J. Richardson Dresser Industries, Inc. J.A. Cox Deluca Test Equipment D.B. DeMichael DuPont Company NBIC Subcommittee on Mandatory Appendices P.D. Edwards, Chairman Stone & Webster, Inc. J.T. Pillow APComPower Inc. R. Sullivan, Secretary The National Board of Boiler and Pressure Vessel Inspectors B. Schulte Reliant Energy, Inc. J. Sekely Wayne Crouse, Inc. S.E. Bacon Conoco Phillips R. C. Sulzer Babcock & Wilcox D.A. Canonico Canonico & Associates R.A. Wacjer Dupont W. Carey International Brotherhood of Boilermakers M. Webb Xcel Energy D. Cook State of California R.V. Wielgoszinski Hartford Steam Boiler Inspection and Insurance Company of Connecticut C. Hopkins Seattle Boiler Works M.R. Peterson State of Alaska v NBIC Subcommittee on Nonmandatory Appendices H.M. Richards, Chairman Southern Company C.A. Neumann Eastman Kodak Company R. Ferrell, Secretary The National Board of Boiler and Pressure Vessel Inspectors J. Richardson Consultant – Dresser, Inc. R. Snyder Arise, Inc. R.R. Cate State of Louisiana H. Staehr Factory Mutual Global W.D. Doty Doty & Associates, Inc S. Staniszewski Jr. U.S. Department of Transportation G.W Galanes Midwest Generation EME, LLC H.N. Titer MIRANT Mid-Atlantic P.C. Hackford State of Utah M.J. Wheel State of Vermont J.P. Larson OneBeacon Insurance J.M. Yagen DYNEGY Midwest Generation R.D. Marvin State of Washington NBIC Subcommittee on Part RA C.A. Neumann, Chairman Eastman Kodak Company J. Richardson Consultant – Dresser Inc. R. Sullivan, Secretary The National Board of Boiler and Pressure Vessel Inspectors B. Schulte Reliant Energy, Inc. R. Snyder Arise, Inc. P.C. Hackford State of Utah H.N. Titer MIRANT Mid-Atlantic R.D. Marvin State of Washington vi NBIC Subcommittee on Part RB R. R. Cate, Chairman State of Louisiana M.R. Peterson State of Alaska H. Staehr, Vice Chair Factory Mutual Global J. M. Richards Southern Company J.F. Ball, Secretary The National Board of Boiler and Pressure Vessel Inspectors J. Sekely Wayne Crouse, Inc. S. Staniszewski Jr. U.S. Department of Transportation S.E. Bacon Conoco Phillips R.A. Wacker Dupont W. Carey International Brotherhood of Boilermakers NBIC Subcommittee on Parts RC & RD C. Hopkins Seattle Boiler Works R.V. Wielgoszinski, Chair Hartford Steam Boiler Inspection and Insurance Co. of Connecticut B. Juarez OneBeacon Insurance R. Ferrell, Secretary The National Board of Boiler and Pressure Vessel Inspectors J.P. Larson OneBeacon Insurance D.A. Canonico Canonico & Associates J.T. Pillow APComPower Inc. D. Cook State of California R.C. Sulzer Babcock & Wilcox W.D. Doty Doty & Associates, Inc. M. Webb Xcel Energy P.D. Edwards Stone & Webster, Inc. M.J. Wheel State of Vermont D. Fox The Oncor Group J.M. Yagen DYNEGY Midwest Generation G.W. Galanes Midwest Generation EME, LLC vii NATIONAL BOARD MEMBERS Alabama ............................................................................................................................................................. Ralph P. Pate Alaska .......................................................................................................................................................... Mark R. Peterson Arizona ....................................................................................................................................................................................... Arkansas ......................................................................................................................................................... Gary R. Myrick California ....................................................................................................................................................... Donald C. Cook Colorado .....................................................................................................................................................Randall D. Austin Connecticut ........................................................................................................................................................ Allan E. Platt Delaware........................................................................................................................................................ James B. Harlan Florida ......................................................................................................................................................................................... Georgia ..................................................................................................................................................................Earl Everett Hawaii................................................................................................................................................................Yash Nagpaul Illinois ............................................................................................................................................................ David A. Douin Indiana ..................................................................................................................................................................... Dan Willis Iowa ...................................................................................................................................................................Robert B. West Kansas .......................................................................................................................................................... Donald J. Jenkins Kentucky ........................................................................................................................................................ Rodney Handy Louisiana .......................................................................................................................................................... Robert R. Cate Maine .............................................................................................................................................................. John H. Burpee Maryland .............................................................................................................................................................. Karl J. Kraft Massachusetts .................................................................................................................................................. Mark Mooney Michigan ...................................................................................................................................................... Robert J. Aben Jr. Minnesota ...........................................................................................................................................................Joel T. Amato Mississippi ................................................................................................................................................ Henry T. McEwen Missouri ............................................................................................................................................................. James L. Pratt Montana...................................................................................................................................................................................... Nebraska......................................................................................................................................................... Daniel E. Burns Nevada.........................................................................................................................................................Gerard F. Mankel New Hampshire ........................................................................................................................................... Wayne Brigham New Jersey .............................................................................................................................................. Milton Washington New Mexico ............................................................................................................................................................................... New York ....................................................................................................................................................... Paul A. Conklin North Carolina............................................................................................................................................. Jack M. Given Jr. North Dakota ......................................................................................................................................................Robert Reetz Ohio ...................................................................................................................................................................Dean T. Jagger Oklahoma .............................................................................................................................................. Marion L. Holloway Oregon ................................................................................................................................................................. Ray Andrus Pennsylvania ...................................................................................................................................................John D. Payton Rhode Island ............................................................................................................................................ Benjamin Anthony South Dakota ............................................................................................................................................... Howard D. Pfaff Tennessee ..........................................................................................................................................................Martin R. Toth Texas ....................................................................................................................................................................... Terry Parks Utah .............................................................................................................................................................. Pete C. Hackford Vermont ...................................................................................................................................................... Malcolm J. Wheel Virginia ..............................................................................................................................................................Fred P. Barton Washington ................................................................................................................................................ Robert D. Marvin West Virginia ............................................................................................................................................... Arthur E. Adkins Wisconsin ............................................................................................................................................... Michael J. Verhagen Chicago, IL ..................................................................................................................................................... Michael J. Ryan Detroit, MI .......................................................................................................................................................Michael Barber Los Angeles, CA .................................................................................................................................................. Jovie Aclaro Milwaukee, WI ............................................................................................................................................. Randal S. Pucek Alberta ................................................................................................................................................................ Ken K.T. Lau British Columbia ..........................................................................................................................................Malcolm Bishop Manitoba......................................................................................................................................................... I. Wayne Mault New Brunswick ................................................................................................................................................... Dale E. Ross Newfoundland & Labrador ................................................................................................................... E. Dennis Eastman Northwest Territories ....................................................................................................................................Steve Donovan Nova Scotia ...................................................................................................................................................Charles J. Castle Nunavet Territory ................................................................................................................................E. William Bachellier Ontario ..................................................................................................................................................................Rick D. Mile Prince Edward Island ................................................................................................................................... Kenneth Hynes Quebec .......................................................................................................................................................... Madiha M. Kotb Saskatchewan .............................................................................................................................................. Nicholas Surtees Yukon Territory .............................................................................................................................................. Daniel C. Price viii NATIONAL BOARD INSPECTION CODE 2004 EDITION INCLUDING 2004 ADDENDUM DATE OF ISSUE — DECEMBER 31, 2004 This code was developed under procedures accredited as meeting the criteria for American National Standards. The Consensus Committee that approved the code was balanced to assure that individuals from competent and concerned interests had an opportunity to participate. The proposed code was made available for public review and comment which provided an opportunity for additional public input from industry, academia, regulatory and jurisdictional agencies, and the public-at-large. The National Board does not “approve,” “rate,” or “endorse” any item, construction, proprietary device, or activity. The National Board does not take any position with respect to the validity of any patent rights asserted in connection with any items mentioned in this document, and does not undertake to insure anyone utilizing a standard against liability for infringement of any applicable Letters Patent, nor assume any such liability. Users of a code are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, is entirely their own responsibility. Participation by federal agency representative(s) or person(s) affiliated with industry is not to be interpreted as government or industry endorsement of this code. The National Board accepts responsibility for only those interpretations issued in accordance with governing National Board procedures and policies which preclude the issuance of interpretations by individual committee members. The footnotes in this document are part of this American National Standard. B R R N I ® B ® NR R R The above National Board symbols are registered with the U.S. Patent Office. “National Board” is the abbreviation for The National Board of Boiler and Pressure Vessel Inspectors. No part of this document may be reproduced in any form, in an electronic retrieval system or otherwise, without the prior written permission of the publisher. ix x FOREWORD The National Board of Boiler and Pressure Vessel Inspectors is an organization comprised of Chief Inspectors for the states, cities and territories of the United States and provinces and territories of Canada. It is organized for the purpose of promoting greater safety to life and property by securing concerted action and maintaining uniformity in the construction, installation, inspection, repair and alteration of pressure retaining items, thereby assuring acceptance and interchangeability among jurisdictional authorities responsible for the administration and enforcement of various codes and standards. In keeping with the principles of promoting safety and maintaining uniformity, the National Board originally published The National Board Inspection Code (NBIC) in 1946, establishing rules for inspection and repairs to boilers and pressure vessels. The National Board Inspection Code (NBIC) Committee is charged with the responsibility for maintaining and revising the NBIC. In the interest of public safety, the NBIC Committee decided, in 1995, to revise the scope of the NBIC to include rules for the repair or alteration to pressure-retaining items. The NBIC Committee’s function is to establish rules of safety governing the repair, alteration and inspection of pressure-retaining items, and to interpret these rules when questions arise regarding their intent. In formulating the rules, the NBIC Committee considers the needs of users, repair organizations, and Inspectors. The objective of the rules is to afford reasonably certain protection of life and property so as to give a reasonably long, safe period of usefulness. Advancements in design and material and the evidence of experience are recognized. The rules established by the NBIC Committee are not to be interpreted as approving, recommending, or endorsing any proprietary or specific design, or as limiting in any way the repair organization’s freedom to choose any method of repair or alteration that conforms to the NBIC rules. The NBIC Committee meets regularly to consider revisions of the rules, new rules, and requests for interpretations. Requests for interpretation must be addressed to the Secretary in writing and must give full particulars in order to receive consideration and a written interpretation (see Mandatory Appendix 1 covering preparation of technical inquiries). Proposed revisions to the Code resulting from inquiries will be presented to the NBIC Committee for appropriate action. Proposed revisions to the Code approved by the NBIC Committee are submitted to the American National Standards Institute and published on the National Board Web site to invite comments from all interested persons. After the allotted time for public review and final approval, revisions are published annually in Addenda to the NBIC. Repair organizations or users of pressure-retaining items are cautioned against making use of revisions that are less restrictive than former requirements without having assurance that they have been accepted by the jurisdiction where the pressur-retaining item is installed. The general philosophy underlying the NBIC is to parallel those provisions of the original code of construction, as they can be applied to a repair or alteration. xi The NBIC does not contain rules to cover all details of repair or alteration. Where complete details are not given, it is intended that the repair organization, subject to the acceptance of the Inspector, provide details for the repair or alteration which will be as safe as otherwise provided by the rules in the original code of construction. Repairs not conforming to the rules of the original code of construction or the NBIC must receive specific approval of the jurisdiction, who may establish requirements for design, inspection, testing and documentation. There are instances where the NBIC serves to warn a repair organization or Inspector against pitfalls; but the Code is not a handbook, and cannot substitute for education, experience, and sound engineering judgment. It is intended that this Edition of the NBIC and any subsequent Addenda not be retroactive. Unless the jurisdiction imposes the use of an earlier edition, the latest effective Edition and Addenda is the governing document. xii INTRODUCTION It is the purpose of the National Board Inspection Code (NBIC) to maintain the integrity of pressure-retaining items after they have been placed into service by providing rules for inspection, repair and alteration, thereby ensuring that these objects may continue to be safely used. The NBIC is intended to provide guidance to jurisdictional Inspectors, users, and organizations performing repairs and alterations, thereby encouraging the uniform administration of rules pertaining to pressure-retaining items. It provides guidance for the process of inspection, repair and alteration but does not provide details for all conditions found in pressure-retaining items. Where complete details are not provided in this Code, the Code user is advised to seek technical guidance. ADDENDA Colored-sheet Addenda, which include revisions and additions to this Code, are published annually. Addenda are permissive on the date issued and become effective six months after the date of issue. The addenda will be sent automatically to purchasers of the Code up to the publication of the next issue. INTERPRETATIONS On request, the NBIC Committee will render an interpretation of any requirement of this Code. Interpretations are not part of this Code or its addenda. JURISDICTIONAL PRECEDENCE Reference is made throughout this Code to the requirements of the “jurisdiction”. Where any provision herein presents a direct or implied conflict with any jurisdictional regulation, the jurisdictional regulation shall govern. AMERICAN PETROLEUM INSTITUTE The American Petroleum Institute promulgates codes and standards for the inspection, repair, alteration, rerating and fitness for service assessment of pressure vessels and piping used by the petroleum and chemical process industries. These codes and standards include: API 510 Pressure Vessel Inspection Code: Maintenance Inspection, Rating, Repair and Alteration. API 570 Piping Inspection Code: Inspection, Repair, Alteration and Rerating of Inservice Piping Systems. API 579 Fitness-for-Service xiii It is the intent of the NBIC that this Code cover installations other than those covered by API codes and standards unless the jurisdiction rules otherwise. UNITS OF MEASUREMENT Both inch-pound units and SI units are used in the NBIC. The value stated in inch-pound units or SI units are to be regarded separately as the standard. Within the text, the SI units are shown in parentheses. A04 US customary units or SI units may be used with this edition of the NBIC, but one system shall be used consistently throughout a repair or alteration of pressure-retaining items. The original code of construction should be used as the basis for selecting the units of measurement for repair or alteration or pressure-retaining items. ORGANIZATION 1. This book is divided into seven parts a. Part RA describes the administrative requirements for the accreditation of repair organizations. b. Part RB provides guidelines for inservice inspection of pressure containing items (boilers, pressure vessels, piping). c. Part RC provides requirements that apply to repairs and alterations of pressure-retaining items. d. Part RD gives guidance for welding methods as alternatives to postweld heat treatment. Some repair methods are described to further give guidance to the owner user, inspector, and repair organizations. e. Mandatory appendices as identified by numerals contain specific rules that are not covered in Parts RA, RB, RC and RD. Their requirements are mandatory when applicable. f. Nonmandatory appendices as identified by letters provide information and suggested good practices. The information provided is not mandatory. However, if used, shall be used in its entirety to the extent applicable. g. Interpretations are provided for information only and are not part of this code. 2. Tables, charts and figures provide relevant illustrations or supporting information for text passages, and are designated with numbers corresponding to the paragraph they illustrate or support. Multiple tables, charts or figures referenced by the same paragraph will have additional numbers reflecting the order of reference. xiv TABLE OF CONTENTS Foreword .......................................................................................................................................... xi Introduction ................................................................................................................................... xiii Part RA Administrative Requirements .............................................................................1 Part RB Inservice Inspection of Pressure-Retaining Items ...........................................31 Part RC Repairs and Alterations ......................................................................................89 Part RD Repair Methods ..................................................................................................105 A04 Part RE Repair of Pressure Relief Valves ......................................................................125 Mandatory Appendices Appendix 1 Preparation of Technical Inquiries to the National Board Inspection Code Committee.............................................................................135 Appendix 2 Stamping and Nameplate Information ..........................................................137 A04 Appendix 3 Steam Locomotive Firetube Boiler Inspection, Repair and Storage ...........141 Appendix 4 Glossary of Terms ..............................................................................................175 Appendix 5 National Board Forms .......................................................................................181 Appendix 6 Examples of Repairs and Alterations..............................................................213 Appendix 7 Procedures to Extend the “VR” Certificate of Authorization Stamp to ASME “NV” Stamped Pressure Relief Devices ............................217 Appendix 8 Inspection, Repair and Alteration of Graphite Pressure Equipment .........221 Appendix 9 Repair, Alteration and Inspection of Fiber-Reinforced Thermosetting Plastic Pressure Equipment ...................................................233 Nonmandatory Appendices Appendix A Standard Welding Procedures .........................................................................277 Appendix B Recommended Preheat Temperatures ............................................................287 Appendix C Historical Boilers................................................................................................291 Appendix D Recommended Guide for the Design of a Test System for Pressure Relief Devices in Compressible Fluid Service ...............................349 xv Appendix E Recommended Procedures for Repairing Pressure Relief Valves ..............355 Appendix F Pressure Differential Between Safety or Safety Relief Valve Setting and Boiler or Pressure Vessel Operating Pressure ...........................361 Appendix G Safety Valves on the Low Pressure Side of Steam Pressure-Reducing Valves ................................................................................365 Appendix H Recommended Guide for the Inspection of Pressure Vessels in LP Gas Service ...............................................................................................371 Appendix I Installation Requirements ................................................................................377 Appendix J Guide to Jurisdictions for Authorization of Owners-Users to Make Adjustments to Pressure Relief Valves ............................................435 Appendx K Inspection, Repairs and Alterations for Yankee Dryers ...............................439 Interpretations ..............................................................................................................................453 Index ..............................................................................................................................507 xvi Administrative Requirements Part RA 1 NATIONAL BOARD INSPECTION CODE PART RA — ADMINISTRATIVE REQUIREMENTS TABLE OF CONTENTS RA-1000 RA-1010 A04 RA-1020 General ................................................................................................................... 3 Scope ....................................................................................................................... 3 Accreditation Process ........................................................................................... 3 RA-2000 RA-2010 A04 RA-2020 RA-2030 A04 Accreditation of Repair Organizations .............................................................. 3 Scope ....................................................................................................................... 3 Scope Issuance and Revision to Pressure-Retaining Items..............................3 Scope Issuance and Revision to Pressure Relief Valves ...................................4 RA-2100 RA-2110 RA-2120 RA-2130 RA-2140 RA-2150 “R” Administrative Rules and Procedures ........................................................4 Scope ....................................................................................................................... 4 Prerequisites for Issuing a National Board Certificate of Authorization...... 4 Procedure for Obtaining or Renewing a National Board Certificate of Authorization.................................................................................................... 5 National Board “R” Symbol Stamp.....................................................................6 Quality System .......................................................................................................6 RA-2200 RA-2210 RA-2220 RA-2230 A04 RA-2240 RA-2250 “VR” Administrative Rules and Procedures .................................................... 9 Scope ....................................................................................................................... 9 Issuance and Renewal of the “VR” Certificate and Stamp ........................... 10 Use of the “VR” Stamp ...................................................................................... 12 Certificate of Authorization Contents ............................................................. 13 Quality System .................................................................................................... 13 RA-2300 RA-2310 RA-2320 “NR” Accreditation Requirements................................................................... 18 Scope ..................................................................................................................... 18 Prerequisites for Issuing a National Board “NR” Certificate of Authorization.................................................................................................. 19 Procedure for Obtaining or Renewing a National Board “NR” Certificate of Authorization .............................................................................. 19 National Board “NR” Symbol Stamp .............................................................. 21 Quality System Program .................................................................................. 22 Outline of Requirements for a Quality System Program for Qualification for the National Board “NR” Symbol Stamp.......................... 22 Interface With the Owner’s Repair/Replacement Program ........................ 29 RA-2330 RA-2340 RA-2350 RA-2360 A04 RA-2370 2 PART RA — ADMINISTRATIVE REQUIREMENTS RA-1000 GENERAL RA-1010 SCOPE This part describes the administrative requirements for the accreditation of repair organizations and for the accreditation of Owner-User Inspection Organizations.1 ACCREDITATION OF REPAIR A04 ORGANIZATIONS RA-2010 SCOPE The National Board administers accreditation A04 programs for authorization of organizations performing repairs and alterations to pressure-retaining items and/or pressure relief valves. A04 The National Board administers three specific accreditation programs as shown below: As part of the accreditation process, an appli- A04 cant’s quality system is subject to a review. National Board procedures provide for the confidential review resulting in recommendations to issue or not issue a Certificate of Authorization. “R” ........ Repairs and Alterations to Pressure-Retaining Items “VR” ..... Repairs to Pressure Relief Valves “NR” ..... Repair and Replacement Activities for Nuclear Items A04 RA-1020 RA-2000 When the quality system requirements of the A04 appropriate section of Part RA have been met, a Certificate of Authorization and appropriate National Board symbol stamp shall be issued. ACCREDITATION PROCESS Any organization may apply to the National Board to obtain a Certificate of Authorization for the requested scope of activities. A review shall be conducted to evaluate the organization’s quality system. The individual assigned to conduct the evaluation shall meet the qualification requirements prescribed by the National Board. Upon completion of the evaluation, any deficiencies within the organization’s quality system will be documented and a recommendation will be made to the National Board regarding issuance of a Certificate of Authorization. The accreditation programs provide require- A04 ments for organizations performing repairs and alterations to pressure-retaining items. Depending upon the expected scope of activities at the time of review, organizations may be authorized to perform design only, metallic or non-metallic repairs, and/or alterations either in the shop only, field only, or shop and field. Repairs and/or alterations to metallic and non-metallic pressure-retaining items are made by welding, bonding and/or mechanical assembly. RA-2020 1 SCOPE ISSUANCE AND REVISION TO PRESSURERETAINING ITEMS Any scope revision shall require authorized inspection agency acceptance of quality system changes. These changes shall be submitted to the National Board for acceptance. A program review may be required by the National Board or the jurisdication to assure Caution, some jurisdictions may independently administer a program of authorization for organizations to perform repairs and alterations within that jurisdiction. 3 A04 NATIONAL BOARD INSPECTION CODE quality system requirements are met for scope changes. Upon acceptance of the changes, the National Board will issue a Certificate of Authorization with a revised scope. A04 RA-2030 Owners or users may be accredited for both a repair and inspection program provided the owner or user complies with the requirements of the “R” program and the National Board requirements for an Owner-User Inspection Organization. The requirements of RA-2120(a) do not apply if the owner or user chooses to use the Owner-User Inspection Organization to accept the repair quality system when: SCOPE ISSUANCE AND REVISION TO PRESSURE RELIEF VALVES The “VR” accreditation program provides requirements for organizations performing repairs to pressure relief valves. For scope issuance and revisions, refer to RA-2200. RA-2100 RA-2110 a. There is no conflict with jurisdictional requirements. b. The line of authority for the Owner-User Inspection Organization shall be independent of the organization responsible for execution of “R” program work. “R” ADMINISTRATIVE RULES AND PROCEDURES c. The process and Inspector limitations are described in the written Owner-User Inspection Organization’s quality system manual. SCOPE This section provides requirements that must be met by organizations in order to obtain a National Board Certificate of Authorization to use the “R” Symbol Stamp for the repair or alteration of pressure-retaining items. Organizations may be authorized to perform repairs only, or repairs and alterations. RA-2120 PREREQUISITES FOR ISSUING A NATIONAL BOARD CERTIFICATE OF AUTHORIZATION Before an organization can obtain a National Board “R” Certificate of Authorization, the organization shall: For further information contact: Accreditation Department The National Board of Boiler and Pressure Vessel Inspectors 1055 Crupper Avenue Columbus, OH 43229-1183 a. Have and maintain an Inspection Agreement with an Authorized Inspection Agency, b. Have, in the English language, a written A04 Quality System which complies with the requirements of this section and includes the expected scope of activities, Phone — 614.888.8320 Fax — 614.847.1828 The issuance of the “R” Stamp is not restricted to organizations whose primary business is to repair and alter pressure retaining items, nor to manufacturers of pressure-retaining items. Owners and Users of pressure-retaining items and other organizations that qualify in accordance with these rules may also obtain the “R” Stamp. c. Have the current edition of the National Board Inspection Code, and d. Have available a copy of the code of construction appropriate to the intended scope of work. 4 PART RA — ADMINISTRATIVE REQUIREMENTS RA-2130 The Review Team shall conduct an evaluation of the organization’s Quality System. The organization shall demonstrate sufficient implementation of the Quality System to provide evidence of the organization’s knowledge of welding, nondestructive examination, postweld heat treatment, and other repair or alteration activities performed appropriate for the requested scope of work. The demonstration may be performed using current work, a demonstration mock-up, or a combination of both. PROCEDURE FOR OBTAINING OR RENEWING A NATIONAL BOARD CERTIFICATE OF AUTHORIZATION Prior to issuance or renewal of a National Board “R” Certificate of Authorization, the organization and its facilities are subject to a review of its Quality System. The implementation of the Quality System shall be satisfactorily demonstrated by the organization. The National Board reserves the absolute right to cancel, refuse to issue or renew such authorization. A recommendation to issue, renew or withhold the National Board Certificate of Authorization shall be included in a Review Report prepared by the Review Team. The completed Review Report shall be forwarded to the National Board. Organizations desiring to obtain a National Board Certificate of Authorization shall apply to the National Board using forms obtained from the National Board. Application for renewal shall be made prior to the expiration date of the Certificate of Authorization. Applications may be obtained from the National Board. If proper administrative fees are paid and all other requirements are met, a Certificate of Authorization will be issued evidencing permission to use the “R” Symbol Stamp. The Certificate shall expire on the triennial anniversary date. When an organization has plants or shops in more than one location, the organization shall submit separate applications for each plant or shop. The organization may perform repairs or alterations in its plants, shops, or in the field, provided such operations are described in the organization’s Quality System. When an organization holding a National Board Certificate of Authorization changes ownership, name, location or address, the National Board shall be notified. The Certificate of Authorization may be revised by submitting an application for National Board “R” Certificate of Authorization; however, a re-review may be required. Upon notification of the review dates from the National Board, it is the responsibility of the organization to make arrangements for the review. The holder of an ASME Code Symbol Stamp, whose facilities were reviewed by the jurisdiction, (with the exception of “V”, “UV”, “HV”, “NV”, “RP”, and “H” [cast iron]) may obtain National Board authorization without a review of its facilities, provided: The Review Team, as a minimum, shall consist of one representative each from the Authorized Inspection Agency and the Jurisdiction.2 a. The organization has a Quality System to cover the scope of the repairs or altera2 Jurisdiction: The National Board member jurisdiction where the organization is located. Alternatively, where the jurisdiction elects not to perform the review or where there is no jurisdiction or where the jurisdiction is the organization’s Authorized Inspection Agency, the National Board of Boiler and Pressure Vessel Inspectors will represent the jurisdiction. At the jurisdiction’s discretion, the jurisdiction may choose to be a member of the review team if the jurisdiction chooses not to be the team leader. 5 NATIONAL BOARD INSPECTION CODE tions to be made, subject to review by the jurisdiction; and has been issued, the “R” Symbol Stamp shall be returned to the National Board. A04 b. The application for the “R” Certificate of Authorization is submitted within twelve months from the issuance of the ASME Certificate of Authorization. The initial Certificate of Authorization shall be issued to expire concurrent with the ASME Certificate of Authorization. Subsequent certificates shall be renewed upon a successful review and implementation of its quality system by a National Board representative. The organization’s Quality System shall provide for adequate control of the “R” Symbol Stamp. Provisions may be made for the issuance of the “R” Symbol Stamp for use at various field locations. The holder of a Certificate of Authorization may obtain more than one “R” Symbol Stamp provided the organization’s Quality System describes how the use of such stamps is controlled from the location shown on the certificate. The jurisdiction may audit the Quality System and activities of an organization upon a valid request from an owner, user, inspection agency or the National Board. An organization shall not permit others to use the “R” Symbol Stamp loaned to it by the National Board. The NBIC Committee may at any time change the rules for the issuance of Certificates of Authorization and use of the “R” Symbol Stamp. These rules shall become binding on all certificate holders. RA-2140 RA-2150 QUALITY SYSTEM A holder of a National Board Certificate of Authorization shall have and maintain a written Quality System. The System shall satisfactorily meet the requirements of the NBIC and shall be available for review. The Quality System may be brief or voluminous, depending on the circumstances. It shall be treated confidentially by the National Board. NATIONAL BOARD “R” SYMBOL STAMP All “R” Symbol Stamps shall be obtained from the National Board of Boiler and Pressure Vessel Inspectors. Authorization to use the “R” Symbol Stamp may be granted by the National Board at its absolute discretion. RA-2151 The “R” Symbol Stamp is furnished on loan by the National Board for a nominal fee. Each organization shall agree, if authorization to use the “R” Symbol Stamp is granted, that the “R” Symbol Stamp is at all times the property of the National Board and will be promptly returned upon demand. If the organization discontinues the use of the “R” Symbol Stamp, inspection agreement with an Authorized Inspection Agency, or if the Certificate of Authorization has expired and no new certificate OUTLINE OF REQUIREMENTS FOR A QUALITY SYSTEM FOR QUALIFICATION FOR THE NATIONAL BOARD “R” SYMBOL STAMP The following is a guide to features of a Quality System that should be included in the organization’s Quality System Manual. Each organization should address the features as needed for the scope of work to be performed: a. Title Page The name and complete address of the company to which the National Board 6 PART RA — ADMINISTRATIVE REQUIREMENTS Certificate of Authorization is issued shall be included on the Title Page of the Quality System Manual. issuance of the manual and implementation. f. b. Contents Page The manual should contain a page listing the contents of the manual by subject, number (if applicable) and revision number of each document. c. Scope of Work The manual shall clearly indicate the scope and type of repairs or alterations the organization is capable of and intends to carry out. Organization 1. An organizational chart shall be included in the manual. It shall include the title of the heads of all departments or divisions that perform functions which can affect the quality of the repair or alteration and it shall show the relationship between each department or division. 2. The manual shall identify the title of those individuals responsible for preparation, implementation or verification of the Quality System. The responsibilities shall be clearly defined and the individuals shall have the organizational freedom and authority to fulfill those responsibilities. d. Statement of Authority and Responsibility A dated Statement of Authority, signed by an officer of the organization, shall be included in the manual. Further, the Statement of Authority shall include: 1. A statement that all repairs or alterations carried out by the organization shall meet the requirements of the NBIC and the jurisdiction as applicable. g. Drawings, Design and Specifications The manual shall contain controls to ensure that all design information, applicable drawings, design calculations, specifications and instructions are prepared or obtained, controlled and interpreted in accordance with the original code of construction. 2. A statement that if there is a disagreement in the implementation of the Quality System, the matter is to be referred for resolution to a higher authority in the company. h. Repair and Alteration Methods The manual shall include controls for repairs and alterations, including the selection of the welding procedure specification, materials, nondestructive examination methods, preheat and postweld heat treatment. Special requirements for Graphite and Fiber Reinforced pressure vessels shall be addressed. 3. The title of the individual who will be responsible to ensure that (1) above is followed and has the freedom and authority to carry out the responsi-bility. e. Manual Control The manual shall include the necessary provisions for revising and issuing documents to maintain the manual current. The title of the individual authorized to approve revisions shall be included in the manual. Revisions must be accepted by the Authorized Inspection Agency prior to i. 7 Materials The manual shall describe the method used to assure that only acceptable materials (including welding material) are used for repairs and alterations. The manual shall include a description of how existing material is identified and new mate- NATIONAL BOARD INSPECTION CODE j. rial is ordered, verified and identified. The manual shall identify the title of the individual(s) responsible for each function and a brief description of how the function is to be performed. m. Calibration The manual shall describe a system for the calibration of examination, measuring and test equipment used in the performance of repairs and alterations. Method of Performing Work The manual shall describe the methods for performing and documenting repairs and alterations in sufficient detail to permit the Inspector to determine at what stages specific inspections are to be performed. The method of repair or alteration must have prior acceptance of the Inspector. n. Acceptance and Inspection of Repair or Alteration The manual shall specifically indicate that before the work is started, acceptance of the repair/alteration shall be obtained from an Inspector who will make the required inspections and confirm NBIC compliance by signing and dating the applicable NBIC Code Report Form3 upon completion of the work. k. Welding, NDE and Heat Treatment The manual shall describe controls for welding, nondestructive examination and heat treatment. The manual is to indicate the title of the individual(s) responsible for the welding procedure specification and its qualification, and the qualification of welders and welding operators. It is essential that only welding procedure specifications and welders or welding operators qualified, as required by the NBIC, be used in the repair or alteration of pressure-retaining items. It is also essential that welders and welding operators maintain their proficiency as required by the NBIC, while engaged in the repair or alteration of pressure-retaining items. The manual shall also describe controls for assuring that the required WPS or SWPS is available to the welder or welding operator prior to welding. Similar responsibility for nondestructive examination and heat treatment shall be described in the manual. l. o. Inspections The manual shall make provisions for the Inspector to have access to all drawings, design calculations, specifications, procedures, process sheets, repair or alteration procedures, test results and other documents as necessary to assure compliance with the NBIC. A copy of the current manual shall be available to the inspector. p. Report of Repair or Alteration Form The manual shall indicate the title of the individuals responsible for preparing, signing and presenting the NBIC Report Forms to the Inspector. The distribution of the NBIC Report Forms shall be described in the manual. q. Exhibits Any forms referenced in the manual shall be included. The form may be a part of the referencing document or included as an appendix. For clarity, the forms may be completed and identified as examples. The name and accepted abbreviations of the “R” Certificate Holder shall be included in the manual. Examinations and Tests Reference shall be made in the manual for examinations and tests upon completion of the repair or alteration. 3 8 NBIC Report Form: National Board Form R-1 for Repairs, Form R-2 for Alterations, or Form R-3 for Parts Fabricated by Welding. PART RA — ADMINISTRATIVE REQUIREMENTS r. For further information contact: Construction Code The manual shall include provisions for addressing the requirements that pertain to the specific construction code for the equipment being repaired or altered. Pressure Relief Department The National Board of Boiler and Pressure Vessel Inspectors 7437 Pingue Drive Worthington, OH 43085-1715 s. Nonconforming Items There shall be a system acceptable to the Inspector for the correction of nonconformities. A nonconformity is any condition which does not comply with the applicable rules of the NBIC, construction code, jurisdictional requirements or the quality system. Nonconformities must be corrected or eliminated before the repaired or altered component can be considered in compliance with the NBIC. RA-2200 “VR” ADMINISTRATIVE RULES AND PROCEDURES RA-2210 SCOPE A04 Phone — 614.888.8320 Fax — 614.848.3474 RA-2212 JURISDICTIONAL PARTICIPATION The National Board member jurisdiction in which the “VR” organization is located is encouraged to participate in the review and demonstration of the applicant’s quality system. The jurisdiction may require participation in the review of the repair organization and the demonstration and acceptance of the repair organization’s quality system manual. These administrative rules and procedures are provided for those who wish to obtain a National Board Certificate of Authorization for use of the “VR” (Repair of Pressure Relief Valves) symbol stamp. It should be noted that the issuance of the “VR” stamp is not restricted to companies whose primary business is the repair of pressure relief valves nor to manufacturers or assemblers that hold an ASME “V”, “HV”, “UV” or “NV” Code symbol stamp. Owners and users of boilers and pressure vessels and other organizations that qualify in accordance with the National Board Rules and Regulations may also obtain the “VR” Certificate and stamp. RA-2213 GENERAL RULES The general rules of the National Board “VR” A04 certification program apply only to the repair of National Board capacity certified ASME Code Section I “V” stamped, Section IV “HV” marked and Section VIII “UV” stamped pressure relief valves that: a. Have been in service or have been A04 exposed to environmental or other conditions such that there is reason to question their ability to perform equivalent to the standards for new valves; or A04 In order to provide due process in the issuance, renewal and revocation of “VR” symbol stamps and certificates of authorization, the National Board Appeals Committee procedures provide an affected “VR” Certificate of Authorization applicant the right of appeal or to provide additional information which may affect the Committee’s decision. b. Any or all of the valve’s external adjustment seals have been broken, opened or otherwise disturbed regardless of the valve’s age or service status. 9 NATIONAL BOARD INSPECTION CODE RA-2214 The National Board may at any time, through the NBIC Committee, modify the regulations concerning the issuance and use of such Valve Repair symbol. All such modified regulations shall become binding upon holders of valid Valve Repair Certificates of Authorization. REPAIR OF NUCLEAR VALVES Provided that the requirements of Appendix 7 and applicable requirements of these rules are met, the “VR” certificate may be extended to apply to the repair of any ASME Code Section III, Class 1, 2 or 3 pressure relief devices which have been capacity certified by the National Board and have been in service, regardless of their intended function, in a nuclear system. RA-2215 Authorization to use the “VR” stamp may be granted or withheld by the National Board in its absolute discretion. If authorization is granted and proper administrative fees paid, a certificate of authorization will be issued evidencing permission to use such a symbol, expiring on the triennial anniversary date. The certificate will be signed by the Chairman of the National Board Board of Trustees, the executive director or any other duly authorized officer. TECHNICAL INQUIRIES Refer to Appendix 1 for information on preparing technical inquiries on the subject of valve repair. RA-2220 ISSUANCE AND RENEWAL OF THE “VR” CERTIFICATE AND STAMP RA-2221 GENERAL The certificate shall list the physical, permanent address of record for the certificate holder’s shop/plant. For field-only scopes, this address of record shown on the Certifi- A04 cate of Authorization is where administrative, technical and quality aspects of the business are controlled. Authorization to use the stamp bearing the official National Board “VR” symbol as shown in Appendix 2 will be granted by the National Board pursuant to the provisions of the following administrative rules and procedures. Appendix 7 provides rules for the repair of ASME Section III “NV” stamped pressure relief devices. RA-2222 RA-2223 RENEWAL OF CERTIFICATE The certificate of authorization is renewable every three (3) years subject to a review of the quality system by a representative of the National Board, review and acceptance of the representative’s report by the National Board and successful completion of capacity verification tests. See RA-2256 for exceptions. The applicant should apply to the National Board for renewal of authorization and reissuance of the certificate prior to the date of expiration. The National Board reserves the absolute right to cancel, refuse to issue or renew such authorization. ISSUANCE OF CERTIFICATE Repair organizations, manufacturers, assemblers or users that make repairs to the American Society of Mechanical Engineers A04 (ASME) Code symbol stamped or marked (as applicable) and The National Board of Boiler and Pressure Vessel Inspectors (National Board) capacity certified pressure relief valves may apply to the National Board for a Certificate of Authorization to use the “VR” symbol. 10 PART RA — ADMINISTRATIVE REQUIREMENTS RA-2224 demonstration site. The demonstration site shall be representative of that typically encountered by the applicant (See RA-2226). A04 REVIEW OF APPLICANT’S FACILITY Before issuance or renewal of pressure relief “VR” Certificates of Authorization, the repair organization, its written quality system and its facilities are subject to a review and verification of implementation of its quality system by a representative of the National Board. The implementation demonstration shall include, as a minimum, disassembly, inspection, repair, application of special processes, reassembly, setting and testing of valves within the scope of the applicant’s quality system. RA-2225 VERIFICATION TESTING Before the “VR” Certificate of Authorization and stamps may be issued or renewed, the demonstration valves must successfully complete capacity and operational verification tests at a National Board accepted testing laboratory. See RA-2226 and RA-2256 for A04 exceptions. The valves shall be typical of those repaired by the organization and within the capabilities of the testing laboratory. The applicant shall repair and submit for verification testing one (1) valve for each Code section (except Section III) and test fluid (steam, air/gas, liquid) which will appear on the certificate of authorization. A minimum of two (2) valves are required regardless of Code sections or test fluid. The valves shall be within the capabilities of the National Board accepted laboratory. When an applicant is A04 using the provisions of RE-2020, the applicant shall submit one additional Section VIII steam valve set on air for verification testing on steam. Tests conducted at the accepted testing laboratory shall be witnessed by a representative of the National Board. The purpose of the tests is to ensure that the repairs have been satisfactorily carried out and the function and operation of the valves meet the requirements of the section of the ASME Code to which they were manufactured. Valves not meeting the function or operational requirements of the section of the ASME Code to which they were manufactured shall be considered to have failed. Replacement valves shall be repaired and selected for testing as stated above, at a rate of two (2) valves for each one (1) that failed. The applicant shall have the latest edition and addenda of the National Board Pressure Relief Device Certifications publication NB-18, The NBIC and the ASME Code section(s) that the organization is including in its scope. a. If either or both of these replacement valves fail to meet the above criteria, the applicant shall document the cause of the noted deficiencies and actions taken to guard against future occurrence. Upon acceptance of this information by the National Board, one (1) additional valve for each replacement valve that failed shall be repaired and tested. The valve(s) shall be of the same ASME Code section, fluid and set pressure scope as the valve previously failing to meet the test requirement. It is the responsibility of the valve repair organization to make arrangements for this review. Certificates cannot be issued or renewed until the National Board is in receipt of approval of this review. Wherever possible, National Board reviews of valve repair organizations shall be coordinated with ASME reviews, when applicable. For field only repair scopes, the review shall encompass both the applicant’s a d d re s s o f re c o rd a n d f i e l d re p a i r 11 NATIONAL BOARD INSPECTION CODE b. Failure of this valve(s) to meet the ASME Code to which the valve was m a n u f a c t u re d s h a l l b e c a u s e f o r consideration by the National Board of revocation of the “VR” Certificate of Authorization or acceptance of alternative corrective action. RA-2226 acceptance of this information by the National Board, one (1) additional valve for each replacement valve that failed shall be repaired and tested. The valve(s) shall be of the same ASME Code section, fluid and set pressure scope as the valve previously failing to meet the test requirement. b. Failure of this valve(s) to meet the ASME Code to which the valve was manufactured shall be cause for consideration by the National Board of revocation of the “VR” Certificate of Authorization or acceptance of alternative corrective action. VERIFICATION TESTING ALTERNATIVES In such cases where all valves repaired by the applicant for a specified ASME Code section or test fluid exceed the capabilities of the accepted testing laboratory, valves for that ASME Code section or test fluid shall be selected as specified in RA-2224 and a demonstration test shall be successfully performed in lieu of verification testing specified in A04 RA-2225 above. The demonstration tests shall be conducted at a facility mutually agreeable to the National Board representative, the facility owner and the applicant. The purpose of these tests is to demonstrate, in the presence of a National Board representative, that the repaired valves shall have adequate seat tightness at the maximum expected operating pressure prior to lifting, shall open within the required set pressure tolerance, operate consistently without chatter and reclose within the required blowdown. RA-2230 USE OF THE “VR” STAMP RA-2231 TECHNICAL REQUIREMENTS A04 The administrative requirements of Part A04 RA-2200 for use of the “VR” stamp shall be used in conjunctin with the technical requirements for valve repair as described in Part RE of the NBIC. Those requirements shall be mandatory when a “VR” repair is performed. RA-2232 STAMP USE A04 If a valve lift-assist device is used by the applicant to establish set pressure after repairs, this device must also be used to set the demonstration valves. Each “VR” symbol stamp shall be used only by the repair firm within the scope, limitations A04 and restrictions under which it was issued. If either of these valves fail to meet the above criteria, then replacement valves shall be repaired and tested at a rate of two (2) valves for each one (1) that failed. RA-2233 RETURN OF STAMP Each applicant shall agree, if authorization to use the stamp is granted, that the stamp is at all times the property of the National Board and will be promptly returned upon demand. If the applicant discontinues the repair of such valves or if the “VR”Certificate of Authoriza- a. If either or both of these replacement valves fail to meet the above criteria, the applicant shall document the cause of the noted deficiencies and actions taken to guard against future occurrence. Upon 12 PART RA — ADMINISTRATIVE REQUIREMENTS tion issued to such applicant has expired and no new certificate has been issued, the stamp will be returned to the National Board. RA-2234 accordance with RA-2224, may be required depending upon the nature and extent of the change to the quality system manual, repair procedures or facilities. Issuance of a new Certificate of Authorization is subject to the procedures herein. MULTIPLE LOCATIONS A holder of a National Board “VR” stamp shall not permit any others to use the “VR” symbol stamp loaned to it by the National Board. When a repair organization, manufacturer or user has a repair department and/or equipment in fixed plants or shops located in more than one geographical area, it must submit separate applications for each plant or shop with the addresses of all such repair locations. A04 RA-2240 RA-2242 The holder of a Certificate of Authorization may obtain more than one “VR” symbol stamp provided its quality system manual controls the use of such stamps from the address of record shown on the Certificate of Authorization. CERTIFICATE OF AUTHORIZATION CONTENTS A04 Qualification for repair location (shop, shop and field, or field only), code section (Section I, III, IV, and/or VIII valves), special processes and test media shall be specified on the repair organization’s “VR” Certificate of Authorization. RA-2241 ISSUANCE OF MORE THAN ONE “VR” SYMBOL STAMP TO A CERTIFICATE OF AUTHORIZATION HOLDER RA-2250 QUALITY SYSTEM RA-2251 GENERAL Each applicant for a new or renewed “VR” Certificate of Authorization shall have and maintain a quality system which shall establish that all of these rules and administrative procedures and applicable ASME Code requirements, including material control, fabrication, machining, welding, examination, setting, testing, inspection, sealing and A04 stamping will be met. CHANGES TO CERTIFICATES OF AUTHORIZATION When a “VR” Certificate Holder intends to change the address of record (location), the certificate holder shall notify the National Board in writing prior to relocating. The new facilities and related quality system for the new location shall be reviewed in accordance with RA-2224. Issuance of a new Certificate of Authorization is subject to the procedures herein. RA-2252 WRITTEN DESCRIPTION A written description, in the English language, A04 of the system the applicant will use shall be available for review and shall contain, as a minimum, the features set forth in RA-2255. This description may be brief or voluminous, depending upon the circumstances, and shall be treated confidentially. In general, the quality system shall describe and explain what documents and procedures the repair firm will use to validate a valve repair. When a “VR” Certificate Holder intends to change ownership or scope, the certificate holder shall notify the National Board in writing prior to the change. A review, in 13 NATIONAL BOARD INSPECTION CODE RA-2253 date, description and section of revision, company approval and National Board acceptance. REVIEW A review of the applicant’s quality system will be performed by a representative of the National Board. The review will include a demonstration of the implementation of the provisions of the applicant’s quality system. RA-2254 c. Contents Page The contents page should list and reference, by paragraph and page number, the subjects and exhibits contained therein. d. Statement of Authority and Responsibility A statement of authority and responsibility shall be dated and signed by an officer of the company. It shall include: MAINTENANCE OF CONTROLLED COPY Each applicant to whom a “VR” Certificate of Authorization is issued shall maintain thereafter a controlled copy of the accepted quality system manual with the National Board. Except for changes which do not affect the quality system, revisions to the quality system manual shall not be implemented until such revisions are accepted by the National Board. RA-2255 1. A statement that the “VR” stamp shall be applied only to pressure relief valves which meet both of the following conditions: a. Are stamped with an ASME “V”, “UV”, or “NV” Code symbol or marked with an ASME “HV” symbol and have been capacity certified by the National Board; and OUTLINE OF REQUIREMENTS FOR A QUALITY SYSTEM b. H a v e b e e n d i s a s s e m b l e d , inspected and repaired by the certificate holder such that the valves’ condition and performance are equivalent to the standards for new valves. The following establishes the minimum requirements of the written description of the quality system. It is required that each valve repair organization develop its own quality system which meets the requirements of its organization. For this reason it is not possible to develop one quality system which could apply to more than one organization. The written description shall include, as a minimum, the following features: 2. The title of the individual responsible to ensure that the quality system is followed and who has authority and freedom to effect the responsibility; a. Title Page The title page shall include the name and address of the company to which the A04 National Board Certificate of Authorization is to be issued. 3. A statement that if there is a disagreement in the implementation of the written quality system, the matter is to be referred to a higher authority in the company for resolution; and b. Revision Log A revision log is required to assure revision control of the quality system manual. The log should contain sufficient space for 4. The title of the individual authorized to approve revisions to the written quality system and the method by which such revisions are to be sub- 14 PART RA — ADMINISTRATIVE REQUIREMENTS mitted to the National Board for acceptance before implementation. 2. State the title of the individual responsible for certification and other records as required. e. Organization Chart A chart showing the relationship between management, purchasing, repairing, inspection and quality control personnel is required and shall reflect the actual organization in place. f. A04 3. All incoming material and parts shall be checked for conformance with the purchase order and, where applicable, the material specifications or drawings. Indicate how material or part is identified and how identity is maintained by the quality system. Scope of Work 1. The scope of work section shall indicate the scope and type of valve repairs, including conversions, the organization is capable of and intends to perform. The location of repairs (shop, shop and field, or field only), ASME Code Section(s) to which the repairs apply, the test medium (air, gas, liquid or steam, or combinations thereof) and special processes (machining, welding, postweld heat treatment or nondestructive examination, or combinations thereof) shall be specifically addressed. i. . 2. The types and sizes of valves to be repaired, pressure ranges and other limitations, such as engineering and test facilities, should also be addressed. g. Drawings and Specification Control The drawings and specification control system shall provide procedures assuring that the latest applicable drawings, specifications and instructions required are used for valve repair, including conversions, inspection and testing. Repair and Inspection Program The repair and inspection program section shall include reference to a document (such as a report, traveler or checklist) which outlines the specific repair and inspection procedures used in the repair of pressure relief valves. Repair procedures shall require verification that the critical parts meet the valve manufacturers specification. Appendix E outlines recommended procedures covering some specific items. Provisions shall be made to retain this document for a period of at least five (5) years. 1. Each valve or group of valves shall be accompanied by the document referred to above for processing through the plant. Each valve shall have a unique identifier (e.g., repair serial number, shop order number, etc.) appearing on the repair documentation A04 and repair nameplate such that traceability is established. 2. The document referred to above shall describe the original nameplate information, including the ASME Code symbol stamping and the repair nameplate information, if applicable. In addition, it shall include material checks, replacement parts, conversion parts (or both), reference to items such as the welding procedure specifications (WPS), fitup, NDE technique, heat treatment and pressure test methods to be used. Application of the h. Material and Part Control The material and part control section shall A04 describe purchasing, receiving, storage and issuing of parts. 1. State the title of the individual responsible for the purchasing of all material. 15 NATIONAL BOARD INSPECTION CODE “VR” stamp to the repair nameplate shall be recorded in this document. Specific conversions performed with the new Type/Model number shall be recorded on the document. There shall be a space for “signoffs” at each operation to verify that each step has been properly performed. The completed Form R-1 shall be noted on and attached to the “VR” Certificate Holder’s document required in RA-2255(i). A04 Similarly, NDE and heat treatment techniques must be covered in the quality system manual. When outside services are used for NDE and heat treatment, the quality system manual shall describe the system whereby the use of such services meet the requirements of the applicable section of the ASME Code. 3. The system shall include a method of controlling the repair or replacement of critical valve parts. The method of identifying each spring shall be indicated. 4. The system shall also describe the controls used to ensure that any personnel engaged in the repair of pressure relief valves are trained and qualified in accordance with RE-3000. A04 j. A04 k. Valve Testing, Setting and Sealing The system shall include provisions that each valve shall be tested, set and all external adjustments sealed according to the requirements of the applicable ASME Code section and the National Board. The seal shall identify the “VR” Certificate Holder making the repair. Abbreviations or initials shall be permitted, provided such identification is acceptable to the National Board. Welding, NDE and Heat Treatment (when applicable) The quality system manual shall indicate the title of the person(s) responsible for and describe the system used in the selection, development, approval and qualification of welding procedure specifications, and the qualification of welders and welding operators in accordance with the provisions of RE-1100 through RE-1160. l. m. Calibration of Measurement and Test Equipment The quality system manual may include controls for the “VR” Certificate Holder to have the pressure relief valve part repaired by a National Board “R” Certificate Holder, per RC-2032 provided the following documentation is provided to the “R” Certificate Holder: 1. The calibration of measurement and test gage system shall include the periodic calibration of measuring instruments, pressure gages and the A04 measuring elements of lift assist devices (e.g., load cells, pressure transducers). 1. Code of Construction, year built 2. Part identification 2. Pressure gages used for setting valves are to be checked periodically (indicate time schedule) by the person authorized (indicate title) in the department. The calibration standard used (master gage or dead weight tester) is to be indicated and results recorded. 3. Part material specified, and A04 Valve Repair Nameplates An effective valve stamping system shall be established to ensure proper stamping of each valve as required by RE-1061. The A04 manual shall include a description of the nameplate or a drawing. 4. “VR” Certificate Holder’s unique identifier as required by RA-2255(i)(1). 16 PART RA — ADMINISTRATIVE REQUIREMENTS 3. All calibration standards shall be calibrated against certified equipment having known valid relationships to nationally recognized standards. marked SAMPLE and completed in a manner typical of actual valve repair procedures. q. Testing Equipment The system shall include a means to control the development, addition or modification of testing equipment to ensure the A04 requirements of RE-2010(b) are met. n. Manual Control The quality system shall include: 1. Measures to control the issuance of and revisions to the quality system manual; r. 2. Provisions for a review of the system in order to maintain the manual current with these rules and the applicable sections of the ASME Code; 1. Provisions for annual audits of field activities shall be included. 3. The title(s) of the individual(s) responsible for control, revisions and review of the manual; 2. Provisions for receipt and inspection of replacement parts, including parts received from the owner-user, shall be addressed. 4. Provision of a controlled copy of the written quality system manual to be submitted to the National Board. A04 A04 Field Repairs (see RE-1070) If field repairs are included in the scope of work, the system shall address any differences or additions to the quality system required to properly control this activity, including the following: 3. If owner-user personnel will assist with repairs, provisions for the use of owner-user personnel shall be included. Revisions shall be submitted for acceptance by the National Board prior to being impletmented. o. Nonconformities The system shall establish measures for the identification, documentation, evaluation, segregation and disposition of nonconformities. A nonconformity is a condition of any material, item, product or process in which one or more characteristics do not conform to the established requirements. These may include, but are not limited to, data discrepancies, procedural and/or documentation deficiencies or material defects. Also, the title(s) of the individual(s) involved in this process shall be included. 4. Provisions for use of owner-user measurement and test equipment, if applicable, shall be addressed. RA-2256 ASME “V”, “HV” OR “UV” CERTIFICATE HOLDERS A manufacturer holding a valid ASME Certificate of Authorization for use of an ASME “V”, “HV” or “UV” Code symbol stamp may obtain the “VR” Certificate of Authorization for the repair of pressure relief valves covered by the ASME Certificate of Authorization and which meet the requirements of RA-2213. This A04 can be accomplished without a review of the facilities provided there is a written quality system to cover the scope of the repairs to be made and the repairs are carried out at the p. Exhibits Forms used in the quality system shall be included in the manual with a written description. Forms exhibited should be 17 NATIONAL BOARD INSPECTION CODE same location where the ASME valves are manufactured. Unless the repaired valves are tested on the same facilities and to the same procedures as new valves, two (2) repaired valves shall be selected by a National Board representative for verification tests. b. Organization Unless the functions which affect the quality of valve repairs are carried out by individuals other than those responsible for manufacturing or assembly, it should not be necessary to revise the organization chart. The initial Certificate of Authorization shall be issued to expire concurrent with the ASME Certificate of Authorization. Subsequent certificates shall be renewed upon a successful review and verification of implementation of its quality system by a National Board representative. This review shall be performed concurrently with the ASME Certificate renewal review. c. General Quality Functions Usually quality system requirements regarding valve repairs may be controlled in the same manner as for ASME manufacturing or assembly provided applicable shop and/or field activities are covered. If this is the case, the applicant for the “VR” stamp should include in its quality system manual a separate section covering valve repairs which references the applicable section of the manual. For a more explicit explanation see RA-2255, Written Descrip- A04 tion of the Quality System. A manufacturer may also perform field repairs of pressure relief valves covered by the ASME Certificate of Authorization provided A04 the provisions of RE-1070 are met. Assemblers holding ASME Certificates of Authorization shall qualify for the “VR” Certificate of Authorization as required elsewhere in these rules. The quality system manual shall be submitted for review and acceptance by the National Board. RA-2300 “NR” ACCREDITATION REQUIREMENTS RA-2310 SCOPE This section provides requirements that must be met for an organization to obtain a National Board Certificate of Authorization to use the “NR” Symbol Stamp for the Repair/Replacement activities performed in A04 accordance with this Part and ASME Section XI requirements. In order for an ASME Code symbol stamp holder to qualify for the National Board “VR” stamp, the following areas to the written quality system usually require attention. a. Statement of Authority and Responsibility This should clearly indicate that valve repairs are carried out in accordance with the requirements and the rules of the National Board and the quality system manual. In addition, the scope and type of valve repairs covered by the manual should be indicated. For further information contact: Accreditation Department The National Board of Boiler and Pressure Vessel Inspectors 1055 Crupper Avenue Columbus, OH 43229-1183 Phone — 614.888.8320 Fax — 614.847.1828 18 PART RA — ADMINISTRATIVE REQUIREMENTS The issuance of the “NR” stamp is not restricted to organizations whose primary A04 business is to perform repair/replacement activities nor to manufacturers or assemblers that hold an ASME “N” type Code symbol stamp. Owners and users of nuclear components and other organizations that qualify in accordance with these rules may also obtain the “NR” stamp. RA-2320 RA-2330 Prior to issuance or renewal of a National Board “NR” Certificate of Authorization, the organization and its facilities are subject to a review of its Quality System Program. The implementation of the Quality System Program shall be satisfactorily demonstrated by the organization. The National Board reserves the absolute right to cancel, refuse to issue or renew such authorization. The National Board will return fees paid for the unexpired term of the certificate. PREREQUISITES FOR ISSUING A NATIONAL BOARD “NR” CERTIFICATE OF AUTHORIZATION Before an organization can obtain a National Board “NR” Certificate of Authorization, the organization shall: A04 PROCEDURES FOR OBTAINING OR RENEWING A NATIONAL BOARD “NR” CERTIFICATE OF AUTHORIZATION O rg a n i z a t i o n s d e s i r i n g t o o b t a i n a National Board Certificate of Authorization shall apply to the National Board using forms obtained from the National Board. Application for renewal shall be made prior to the expiration date of the Certificate of Autho- A04 rization. a. Have and maintain an inspection agreement with an accredited Nuclear Inspection Agency in accordance with NB-360,4 NB-369,5 and ASME Section XI. A04 b. Have in the English language a written Quality System Program that complies with the requirements of this section and addresses controls for the intended scope of activities, These procedures also apply to qualified organizations that make repairs to ASME Section III “NV” pressure relief devices. An organization that holds a valid “NR” Certificate of Authorization shall, for the purpose of these procedures, be known as an authorized nuclear repair organization. A04 c. Have a current edition and addenda of the NBIC, and d. Have available copies of the original code of construction appropriate to the intended scope of work and the appliA04 cable edition and addenda of ASME Section XI, as required by the regulatory authority.6 Authorized Nuclear Inspection Agencies and Inspectors referred to in these procedures shall meet the requirements of and have been qualified and commissioned in accordance with the National Board Rules for Commissioned A04 Inspectors. NB-360, Criteria for Acceptance of Authorized Inspection Agencies for New Construction. 4 NB-369, Qualification and Duties for Authorized Inspection Agencies (AIAs) Performing In-Service Inspection Activities and Qualification of Inspectors of Boilers and Pressure Vessels. 5 Regulatory Authority. A federal government agency, such as the United States Nuclear Regulatory Commission, empowered to issue and enforce regualtions concerning the design, construction, and operation of nuclear power plants. 3 19 NATIONAL BOARD INSPECTION CODE A04 Repair/replacement activities performed under the “NR” Certificate of Authorization must be in accordance with the provisions of the NBIC, Section XI of the ASME Code and the rules of the jurisdiction. ASME Section III pressure relief valves and also meet the applicable requirements for “NR” certification and Appendix 7. When these requirements have been met, the applicant may be issued an “NR” Certificate of Authorization which clearly outlines the scope of work for Section III pressure relief devices. Each authorized nuclear repair organization shall maintain a documented Quality System Program which meets the requirements of RA-2360. The Quality System Program shall be commensurate with the scope of the organization’s activities and shall be acceptable to the jurisdiction, the Authorized Nuclear Inspection Agency and the National Board. The jurisdiction will be the National Board member jurisdiction in which the applicant is located. If the implementation of the Quality System Program takes place outside of the jurisdiction where the applicant’s program was reviewed, the National Board member in the jurisdiction where the implementation takes place may participate in this portion of the survey. At the request of the jurisdiction, the National Board representative may also act for said jurisdiction. Before an “NR” Certificate of Authorization will be issued or renewed, the applicant must have the Quality System Program and the implementation of the program reviewed and found acceptable by representatives of the National Board, the jurisdiction and the A04 accreditated Authorized Nuclear Inspection Agency. If the applicant is an ASME “N” type certificate of authorization holder, has demonstrated within the last 12 months the implementation of the quality program and can verify by documentation that the organization is capable of implementing its quality program as being in compliance with this part, a further verification implementation by the survey team may not be necessary. Where there is no National Board member jurisdiction, the applicant’s Quality System Program shall be acceptable to representatives of the National Board and the Authorized Nuclear Inspection Agency. The applicant shall request the National Board to evaluate the Quality System Program and implementation prior to the issuance of an “NR” Certificate of Authorization. The National Board, when requested through the appropriate form, will arrange for an evaluation of the applicant’s Quality System Program. The program will be evaluated on the basis of its compliance with the National Board rules for certification. The program shall be adequate to control the intended scope of A04 work. The “NR” Certificate of Authorization which is issued shall specify the scope and limits of work for which the applicant is certified. Applicants that do not hold valid ASME “N” type certificates of authorization shall demonstrate, by documentation and actual implementation, that they are capable of A04 performing repair/replacement activities in accordance with the requirements of Section XI and the scope of their application for an “NR”Certificate of Authorization. For National Board authorization to repair ASME “NV”/”NB” stamped pressure relief devices, the applicant shall hold a valid “VR” Certificate of Authorization for the repair of 20 PART RA — ADMINISTRATIVE REQUIREMENTS Revisions to the Quality System Program shall be acceptable to the Authorized Nuclear Inspector Supervisor of the Authorized Nuclear Inspection Agency before implementation. The National Board may at any time change the rules for the issuance of the Certificate of Authorization and use of the “NR” Symbol Stamp. These rules shall become binding on all certificate holders. The “NR” Certificate of Authorization holder shall be subject to an audit annually by the Authorized Nuclear Inspection Agency to assure compliance with the Quality System Program. RA-2340 NATIONAL BOARD “NR” SYMBOL STAMP All “NR” Symbol Stamps shall be obtained from the National Board of Boiler and Pressure Vessel Inspectors. Authorization to use the “NR” Symbol Stamp may be granted by the National Board at its absolute discretion. A04 Upon notification of the survey dates from the National Board, it is the responsibility of the organization to make arrangements for the survey. The National Board, for a nominal fee, fur- A04 nishes the “NR” Symbol Stamp. Each organization shall agree, if authorized to use the “NR” Symbol Stamp, that the “NR” Symbol Stamp is at all times the property of the National Board and will be promptly returned upon demand. If the organization discontinues the use of the “NR” Symbol Stamp or if the Certificate of Authorization has expired and no new Certificate of Authorization has been issued, the “NR” Symbol Stamp shall be returned to the National Board. The Survey Team, as a minimum, shall consist of one representative each from the National Board, Authorized Nuclear Inspection Agency and jurisdiction. A recommendation to issue, renew or withhold the National Board Certificate of AuA04 thorization for the “NR” Symbol Stamp shall be included in a summary report prepared by the survey team leader. The completed summary report shall be forwarded to the National Board. The organization’s Quality System Program shall provide for adequate control of the “NR” Symbol Stamp. If proper administrative fees are paid and all other requirements are met, an A04 “NR” Certificate of Authorization will be issued evidencing authorization to use the “NR” Symbol Stamp. The Certificate shall expire on the triennial anniversary date. The organization authorized to use the “NR” A04 Symbol Stamp may obtain more than one “NR” Symbol Stamp provided the organization’s Quality System Program describes how the use of such stamps are controlled from the location shown on the “NR” Certificate of Authorization. When an organization holding a National Board Certificate of Authorization changes ownership, name or address, the National Board shall be notified. The Certificate of Authorization may be revised by submitting an application for National Board “NR” Certificate of Authorization. The organization shall not permit other or- A04 ganizations to use the “NR” Symbol Stamp loaned to it by the National Board. 21 NATIONAL BOARD INSPECTION CODE RA-2350 functions shall have sufficient and well-defined responsibility, authority and organizational freedom to: QUALITY SYSTEM PROGRAM A holder of a National Board Certificate of Authorization shall have and maintain a written Quality System Program. The system shall satisfactorily meet the requirements of the NBIC, jurisdictional requirements and shall be available for review. The Quality System Program may be brief or voluminous, depending on the circumstances. It shall be treated confidentially by the National Board. RA-2360 a. Identify quality problems; b. Initiate action which results in solutions; c. Verify implementation of solutions to those problems; d. Control further processing, delivery or installation of a nonconforming item, deficiency or unsatisfactory condition until proper disposition has been made. OUTLINE OF REQUIREMENTS FOR A QUALITY SYSTEM PROGRAM FOR QUALIFICATION FOR THE NATIONAL BOARD “NR” SYMBOL STAMP 2. The person and organization responsible for defining and for measuring the overall effectiveness of the Quality System Program shall be designated sufficiently independent from the pressure of production, have direct access to responsible management at a level where appropriate action can be required and report regularly on the effectiveness of the program. Assurance of quality requires management measures which provide that the individual or group assigned the responsibility of inspection, testing, checking or otherwise verifying that an activity has been correctly performed, is independent of the individual or group directly responsible for performing the specific activity. The specific responsibilities of the Quality Assurance organization of the “NR” Certificate Holder shall include the review of written procedures and monitoring of all activities concerned with the Quality System Program as covered in these rules. These rules set forth the requirements for A04 planning, managing and implementing the organization’s Quality System Programs for controlling the quality of activities performed during repair/replacement activities of components and systems in nuclear power plants within the scope of the applicable edition and addenda of Section XI of the ASME Code. These rules are to be the basis for evaluating such programs prior to the issuance of the National Board “NR” Certificate of Authorization. a. Organization 1. The authority and responsibility of those in charge of the Quality System Program and activities affecting quality shall be clearly established and documented. The person and organization performing Quality System 22 PART RA — ADMINISTRATIVE REQUIREMENTS b. Quality System Program and for timely and positive corrective actions. 1. Before becoming a holder of an “NR” Certificate of Authorization, the applicant shall establish a Quality System Program for the control of the quality of work to be performed. The program shall define the organizational structure within which the Quality System Program is to be implemented and shall clearly delineate the responsibilities, levels of authority and lines of communication for the various individuals involved. The program shall be documented in detail in a Quality System Manual which shall be a major basis for demonstration of compliance with the NBIC. The applicant’s Quality System Program shall be documented by written policies, procedures and instructions and shall be based on the organization’s scope of work to be performed. 3. The program shall provide for indoctrination and training of personnel performing activities affecting quality as necessary to assure that suitable proficiency is achieved and maintained. It shall be the responsibility of the “NR” Certificate Holder to assure that all personnel performing quality functions within the scope of these rules, including personnel of subcontracted services, are qualified as specified in these rules. The assignment of qualified personnel shall be at the discretion of the “NR” certificate holder. 4. The “NR” Certificate Holder shall be responsible for advising his Authorized Nuclear Inspection Agency of any proposed changes to the Quality System Manual and shall have acceptance of the Authorized Nuclear Inspection Agency’s Authorized Nuclear Inspector Supervisor before putting such changes into effect. The “NR” Certificate Holder shall A04 make a current copy of the Quality System Manual available to the Authorized Nuclear Inspector. The “NR” Certificate Holder shall be responsible for promptly notifying the Authorized Nuclear Inspector of such accepted changes, including evidence of acceptance by the Authorized Nuclear Inspection Agency. 2. The applicant’s program need not be in the same format or sequential arrangement as the requirements in these rules as long as all applicable program requirements have been covered. The program shall provide for the accomplishment of activities affecting quality under suitably controlled conditions. Controlled conditions include the use of appropriate equipment, suitable environmental conditions for accomplishing the activity and assurance that prerequisites for the activity have been satisfied. The program shall take into account the need for special controls, processes, test equipment, tools and skills to attain the required quality and need for the verification of quality by inspection and test. The program shall provide for ready detection of nonconforming material and items 5. The quality of all repair/replace- A04 ment activities shall be controlled at all points necessary to assure conformance with the requirements of these rules and the “NR” Certificate Holder’s Quality System Manual. 23 NATIONAL BOARD INSPECTION CODE 6. The certificate holder shall make available to the Authorized Nuclear Inspector such drawings and process sheets as are necessary to make the Quality System Program intelligible. esary to assure their compliance with the owner’s design specifications and IWA- A04 4000 of Section XI of the ASME Code. To the extent necessary, procurement documents shall require suppliers to maintain a Quality System Program consistent with the applicable requirements of the edition and addenda of the code of construction to which the items are constructed. Measures shall be established to assure that all purchased material, items and services conform to these requirements. c. Design Control ASME Section XI establishes that the A04 owner is responsible for design in connection with repair/replacement activities. The “NR” Certificate Holder must ensure that the design specification, drawings or other specifications or instructions furnished by the owner satisfy the code edition and addenda of the owner’s design specification. To satisfy this requirement, the “NR” Certificate Holder shall establish requirements that correctly incorporate the owner’s design specification requirements into their specification, drawings, procedures and instructions which may be necessary to carry out the work. The “NR” Certificate Holder’s system shall include provisions to assure that the appropriate quality standards are specified and included in all quality records. These records shall be reviewed for compliance with the owner ’s design specification and the requirements of Section XI of the ASME Boiler and Pressure Vessel Code. A04 e. Instructions, Procedures and Drawings Activities affecting quality shall be prescribed by documented instructions, procedures or drawings of a type appropriate to the circumstances and shall be accomplished in accordance with these instructions, procedures or drawings. Instructions, procedures or drawings shall include appropriate quantitative and qualitative criteria for determining that activities affecting quality have been satisfactorily accomplished. The “NR” Certificate Holder shall maintain a written description of procedures, instructions A04 or drawings used by his organization for control of quality and examination requirements detailing the implementation of the Quality System requirements. Copies of these procedures shall be readily available to the Authorized Nuclear Inspector. If the “NR” Certificate Holder’s specifications, drawings, procedures and instructions conflict with the owner’s design specification, a system must be implemented that will resolve or eliminate the deficiency. This system must be reconciled with the owner and the “NR” Certificate Holder in accordance with IWA-4000 of Section XI of the ASME Code. f. d. Procurement Document Control Documents for procurement of materials, items and subcontracted services shall include requirements to the extent nec- 24 Document Control The program shall include measures to control the issuance, use and disposition of documents, such as specifications, instructions, procedures and drawings, including changes thereto. These measures shall assure that the latest applicable documents, including changes, are reviewed for adequacy and approved for release by authorized personnel and distributed for use at the location where the prescribed activity is performed. PART RA — ADMINISTRATIVE REQUIREMENTS g. Control of Purchased Material, Items and Services Measures shall be established to assure that all purchased material, items and services conform to the requirements of the owner’s design specifications and A04 applicable edition and addenda of the code of construction and Section XI of the ASME Code. These measures shall include identification for material traceability. Provisions shall be identified for source evaluation and objective evidence shall be provided evidencing quality standards for material examination upon receipt. any additional requirements specified in the original code of construction. The Certified Material Test Report or Certificate of Compliance need not be duplicated in the checklist or documents. Checklist documents shall provide a record that the Certified Material Test Report and Certificates of Compliance have been received, reviewed and found acceptable. When the “NR” Certificate Holder Scope authorizes the organization to perform examinations and tests in accordance with the original code of construction, the “NR” Certificate Holder shall certify compliance either on a Certified Material Test Report or Certificate of Conformance that the material satisfies the original code of construction requirements. h. Identification and Control of Material and Items A04 1. Measures shall be established for identification and control of material and items, including partially fabricated assemblies. These measures shall assure that identification is maintained and traceable, either on the material or component, or on records throughout the repair/replacement activity. These measures shall be designed to prevent the use of incorrect or defective items and those which have not received the required examinations, tests or inspections. i. 1. The “NR” Certificate Holder shall operate under a controlled system such as process sheets, checklists, travelers or equivalent procedures. Measures shall be established to assure that processes such as welding, nondestructive examination and heat treating are controlled in accordance with the rules of the applicable section of the ASME Code and are accomplished by qualified personnel using qualified procedures. 2. Permanent or temporary unit identification marks shall be applied using methods and materials which are legible and not detrimental to the component or system involved. Such identification shall be located in areas that will not interfere with the function or quality aspects of the item. A04 Control of Processes 2. Process sheets, checklists, travelers or equivalent documentation shall be prepared, including the document numbers and revisions to which the process conforms, with space provided for reporting results of completion of specific operations at checkpoints of repair/replacement A04 activities. 3. Certified Material Test Reports shall be identified as required by the applicable material specification in Section II of the ASME Code and shall satisfy 25 NATIONAL BOARD INSPECTION CODE j. 2. Test procedures shall include provisions for assuring that prerequisites for the given test have been met, that adequate instrumentation is available and used and that necessary monitoring is performed. Prerequisites may include calibrated instrumentation, appropriate equipment, trained personnel, condition of test equipment and the item to be tested, suitable environmental conditions and provisions for data acquisition. Examinations, Tests and Inspections 1. In-process and final examinations and tests shall be established to assure conformance with specifications, drawings, instructions and procedures which incorporate or reference the requirements and acceptance limits contained in applicable design documents. Examination activities to verify the quality of work shall be performed by persons other than those who performed the activity being examined. Such persons shall not report directly to the immediate supervisors responsible for the work being examined. 3. Test results shall be documented and evaluated to assure that test requirements have been satisfied. l. 2. Process sheets, travelers or checklists shall be prepared, including the document numbers and revision to which the examination or test is to be performed, with space provided for recording results. A04 3. Mandatory hold/inspection points at which witnessing is required by the “NR” Certificate Holder ’s representative or the Authorized Nuclear Inspector shall be indicated in the controlling documents. Work shall not proceed beyond mandatory hold/inspection points without the consent of the “NR” Certificate Holder’s representative or the Authorized Nuclear Inspector, as appropriate. C o n t r o l o f M e a s u r i n g a n d Te s t Equipment Measures shall be established and documented to assure that tools, gages, instruments and other measuring and testing equipment and devices used in activities affecting quality are of the proper range, type and accuracy to verify conformance to established requirements. A procedure shall be in effect to assure that they are calibrated and properly adjusted at specified periods or use intervals to maintain accuracy within specified limits. Calibration shall be traceable to known national standards, where A04 these standards exist, or with the device manufacturer’s recommendation. m. Quality Records 1. The owner is responsible for designating records to be maintained. Measures shall be established for the “NR” Certificate Holder to maintain these records [See m(2)] required for Quality Assurance of repair/replacement activities. A04 These shall include documents such as records of materials, manufac- k. Test Control 1. Testing shall be performed in accordance with the owner’s written test procedures which incorporate or reference the requirements and acceptance limits contained in applicable design documents. 26 PART RA — ADMINISTRATIVE REQUIREMENTS A04 A04 A04 A04 turing, examination and test data taken before and during repair/ replacement activity, procedures, specifications and drawings used shall be fully identified by pertinent material or item identification numbers, revision numbers and issue dates. The records shall also include related data such as qualification of personnel, procedures, equipment and related repairs. The “NR” Certificate Holder shall take such steps as may be required to provide suitable protection from deterioration and damage for all records while in his care. Also it is required that the “NR” Certificate Holder have a system for connection or amending records that satisfies the owner’s requirements. These records may be either the original or a reproduced, legible copy and shall be transferred to the owner at his request. e. As-built sketch(es) including A04 tabulations of materials repair/replacement procedures and instructions to achieve compliance with Section XI of the ASME Code; f. g. Records of all heat treatments. These records may be either the heat treatment charts or a summary description of heat treatment time and temperature data certified by the “NR” Certificate Holder. Heat treatments performed by the material manufacturer to satisfy requirements of the material specifications may be reported on the Certified Material Test Report; 2. Records to be maintained as required in RA-2360(m)(1) above may include the following: a. An index that details the location and who is responsible for maintaining the records; h. Any and all non-conformance reports shall satisfy IWA-4000 of Section XI of the ASME Code and shall be reconciled by the owner prior to certification of the Form NR-1 or NVR-1 as applicable. b. Data reports, properly executed, for each replacement component, part, appurtenance, piping system and piping assembly when required by the design specification or the owner; A04 3. After a repair/replacement activity, all records including audit reports A04 required to verify compliance with the applicable engineering documents and the “NR” Certificate Holder’s Quality System Program, except those required by the owner or listed in (2)(a) through (g) above, shall be maintained at a place mutually agreed upon by the owner and the “NR” Certificate Holder. These records shall be c. The required as-constructed drawings certified as to correctness; A04 Nondestructive examination reports including results of examinations. These reports shall A04 identify the ASNT, SNT-TC-1A, CP-189 or ACCP level of personnel for interpreting the examination results. Final radiographs shall be included where radiography has been performed; d. Copies of applicable Certified Material Test Reports and Certificates of Compliance; 27 NATIONAL BOARD INSPECTION CODE A04 A04 maintained for a period of five years after completion of the repair/replacement activity. amined in accordance with the applicable procedures. Measures which control further processing of a nonconforming or defective item, pending a decision on its disposition, shall be established and maintained. Ultimate disposition of nonconforming items shall be documented. 4. The original of the completed Form NR-1 or Form NVR-1, as applicable, shall be registered with the National Board and, if required, a copy forwarded to the jurisdiction where the nuclear power plant is located. p. Corrective Action 1. Measures shall be established to assure that conditions adverse to quality such as failures, malfunctions, deficiencies, deviations, defective material and equipment and other nonconformances are promptly identified and corrected. n. Examination or Test Status Measures shall be established to indicate A04 examination and test status of parts, items or components during the repair/ replacement activity. The system used shall provide positive identification of the part, item or component by means of stamps, labels, routing cards or other acceptable methods. The system shall include any procedures or instructions to achieve compliance. Also, measures shall be provided for the identification of acceptable and non-acceptable items. They shall also include procedures for control of status indicators, including the authority for application and removal of status indicators. 2. In the case of significant conditions adverse to quality, the measures shall also assure that the cause of these conditions be determined and corrected to preclude repetition. The identification of significant conditions adverse to quality, the cause and condition and the corrective action taken shall be documented and reported to the appropriate levels of management. o. Nonconforming Materials or Items Measures shall be established to control materials or items which do not conform to requirements in order to prevent their inadvertent use, including measures to identify and control the proper installation of items and to preclude nonconformance with the requirements of these rules. These measures shall include procedures for identification, documentation, segregation and disposition. Nonconforming items shall be reviewed for acceptance, rejection or repair in accordance with documented procedures. The responsibility and authority for the disposition of nonconforming items shall be defined. Repaired or modified items shall be reex- 3. The requirements shall also extend to the performance of subcontractors’ corrective action measures. q. Audits A comprehensive system of planned and periodic audits shall be carried out by the “NR” certificate holder’s organization to assure compliance with the Quality System Program and to determine its effectiveness. Audits shall be performed in accordance with written procedures or checklists by personnel not having direct responsibilities in the areas being audited. Audit results shall be documented by the auditing personnel for review by management having responsibility in that area. Follow-up action, including re-audit of deficient areas, shall be taken 28 PART RA — ADMINISTRATIVE REQUIREMENTS where indicated. Audit results shall be made available to the Authorized Nuclear Inspector. r. A04 A04 1, as applicable. The completed forms shall be signed by a representative of the authorized nuclear repair organization and the Authorized Nuclear Inspector if the repair/replacement activity meets A04 the requirements of ASME Section XI. For repair/replacement activities that involve design changes as specified in RA-2360(c), Form NR-1 or Form NVR-1, as applicable, shall indicate the responsible organization satisfying the owner’s design specification requirements. Authorized Nuclear Inspector Measures shall be taken to reference the commissioned National Board Authorized Nuclear Inspector, qualified in accordance with the National Board Rules for Commissioned Inspectors, to ensure that the latest documents including the Quality System Program will be made available to the inspector. The Authorized Nuclear Inspector shall be consulted prior to the issuance of a repair/replacement program in order that he may select any inspection or hold points in the program. The Authorized Nuclear Inspector shall not sign Form NR-1 or Form NVR-1, as applicable, unless he is satisfied that all work carried out is in accordance with the NBIC, ASME Section XI and any jurisdictional requirements. RA-2370 d. The authorized nuclear repair organization shall provide a copy of the signed Form NR-1 or Form NVR-1, as applicable, to the owner, if required, the jurisdiction A04 and the Authorized Nuclear Inspection Agency. The original Form NR-1 or Form NVR-1, as applicable, shall be registered with the National Board by the authorized nuclear repair organization. e. The authorized nuclear repair organization shall provide a nameplate/stamping for repair/replacement activities for A04 each nuclear component unless otherwise required by the Owner’s Quality System Program. The required information and format shall be as shown in Appendix 2. INTERFACE WITH THE OWNER’S REPAIR/ REPLACEMENT PROGRAM A04 Interface with the owner’s repair/replacement program shall meet the following: A04 a. The repair/replacement program shall be subject to the acceptance of the jurisdiction and the owner’s ANII. A04 b. Repair/replacement activities of nuclear components shall meet the requirements of Section XI of the ASME Boiler and Pressure Vessel Code and the jurisdiction where the nuclear power plant is located. A04 c. Documentation of the repair/replacement activities of nuclear components shall be recorded on the National Board Report of Nuclear Repair/Modification or Replacement activities, Form NR-1 or Form NVR- 29 NATIONAL BOARD INSPECTION CODE 30 Inservice Inspection of Pressure-Retaining Items Part RB 31 NATIONAL BOARD INSPECTION CODE PART RB — INSERVICE INSPECTION OF PRESSURE-RETAINING ITEMS RB-1000 RB-1010 RB-1020 RB-1030 RB-1040 RB-1050 General Requirements for Inservice Inspection of Pressure-Retaining Items ...............................................................................36 Scope ......................................................................................................................36 Administration .....................................................................................................36 Stamping ...............................................................................................................36 Reference to Other Codes and Standards ........................................................37 Conclusions ..........................................................................................................37 RB-2000 RB-2010 Personnel Safety and Inspection Activities ......................................................37 Scope ......................................................................................................................37 RB-2100 RB-2110 RB-2120 Personnel Safety ...................................................................................................38 Equipment Operation .........................................................................................38 Vessel Entry Requirements .................................................................................38 RB-2200 RB-2210 RB-2220 RB-2230 Inspection Activities ............................................................................................38 Preparation for Internal Inspection ...................................................................38 Pre-inspection Activities .....................................................................................39 Post-inspection Activities ...................................................................................40 RB-3000 RB-3010 Inspection and Test Methods .............................................................................40 Scope ......................................................................................................................40 RB-3100 RB-3110 RB-3120 RB-3130 RB-3140 RB-3150 RB-3160 RB-3170 RB-3180 Nondestructive Examination Methods (NDE) ................................................40 Visual .....................................................................................................................41 Magnetic Particle .................................................................................................41 Liquid Penetrant ..................................................................................................41 Ultrasonic ..............................................................................................................41 Radiography .........................................................................................................42 Eddy Current........................................................................................................42 Metallographic .....................................................................................................42 Acoustic Emission ...............................................................................................43 RB-3200 RB-3210 RB-3220 Testing ...................................................................................................................43 Pressure Testing ...................................................................................................43 Leak Testing ..........................................................................................................44 RB-3300 Material Preparation – General Guidelines .....................................................44 RB-4000 RB-4010 RB-4020 Causes of Deterioration and Failure Mechanisms ..........................................44 Scope ......................................................................................................................44 General ..................................................................................................................44 RB-4100 RB-4110 RB-4120 Corrosion ..............................................................................................................44 Macroscopic Corrosion Environments .............................................................44 Microscopic Corrosion Environments ..............................................................46 32 PART RB — INSERVICE INSPECTION OF PRESSURE-RETAINING ITEMS RB-4200 RB-4210 RB-4220 RB-4230 RB-4240 RB-4250 Control of Corrosion ...........................................................................................46 Process Variables..................................................................................................46 Engineering Design .............................................................................................46 Protection ..............................................................................................................47 Material Selection ................................................................................................47 Coatings ................................................................................................................47 RB-4300 Conclusion ............................................................................................................47 RB-4400 RB-4410 RB-4420 RB-4430 RB-4440 RB-4450 RB-4460 RB-4470 RB-4480 Failure Mechanisms ............................................................................................47 Fatigue ...................................................................................................................47 Creep .....................................................................................................................48 Temperature .........................................................................................................48 Hydrogen Attack .................................................................................................48 Hydrogen Embrittlement ...................................................................................49 Bulges And Blisters .............................................................................................50 Overheating ..........................................................................................................50 Cracks ....................................................................................................................50 RB-4500 Specific Inspection Requirements .....................................................................50 RB-5000 RB-5010 Inspection of Boilers ............................................................................................50 Scope ......................................................................................................................50 RB-5100 General Conditions .............................................................................................51 RB-5200 Pre-Inspection Activities .....................................................................................51 RB-5300 RB-5310 Condition of Installation.....................................................................................51 General ..................................................................................................................51 RB-5400 RB-5410 RB-5420 RB-5430 Inspections ............................................................................................................51 External Inspection ..............................................................................................51 Internal Inspection ...............................................................................................51 Evidence of Leakage............................................................................................52 RB-5500 RB-5510 RB-5520 Inspection Requirements – General ..................................................................53 Corrosion ..............................................................................................................53 Inspection of Piping, Parts and Appurtenances..............................................54 RB-5600 Specific Inspection Requirements for Boiler Types.........................................57 RB-5700 Inservice Inspection Activities ...........................................................................63 RB-6000 RB-6010 Inspection of Pressure Vessels ...........................................................................63 Scope ......................................................................................................................63 RB-6100 General Conditions .............................................................................................63 33 NATIONAL BOARD INSPECTION CODE RB-6200 RB-6210 RB-6220 RB-6230 RB-6240 RB-6250 Inspections – General Requirements ................................................................63 Condition of Installation.....................................................................................63 External Inspection ..............................................................................................63 Internal Inspection ...............................................................................................65 Inspection of Parts and Appurtenances ...........................................................65 Gages, Safety Devices and Controls .................................................................65 RB-6300 Records Review....................................................................................................66 RB-6400 RB-6410 RB-6420 RB-6430 RB-6440 RB-6450 RB-6460 RB-6470 RB-6480 RB-6490 Inspections For Specific Types of Pressure Vessels .........................................67 General ..................................................................................................................67 Deaerators .............................................................................................................67 Compressed Air Vessels ......................................................................................67 Expansion Tanks ..................................................................................................68 Liquid Ammonia Vessels ....................................................................................69 Inspection of Pressure Vessels with Quick Actuating Closures ....................70 Graphite Pressure Equipment ...........................................................................72 Fiber Reinforced Vessels .....................................................................................72 Propane LP Gas Vessels ......................................................................................72 RB-6500 Nondestructive Examination (NDE) ................................................................72 RB-6600 Remaining Life and Inspection Intervals .........................................................72 RB-6700 Inservice Inspection Activities ...........................................................................72 RB-7000 RB-7010 Inspection of Piping Systems .............................................................................72 Scope ......................................................................................................................72 RB-7100 General Conditions .............................................................................................73 RB-7200 Assessment of Piping Design.............................................................................73 RB-7300 RB-7310 RB-7320 RB-7330 RB-7340 RB-7350 Inspection..............................................................................................................73 External Inspection of Piping.............................................................................73 Internal Inspection of Piping .............................................................................74 Evidence of Leakage............................................................................................74 Provisions for Expansion and Support............................................................74 Gages, Safety Devices, Controls ........................................................................74 RB-7400 Inservice Inspection Activities ...........................................................................75 RB-8000 RB-8010 Inspection of Pressure Relief Devices ...............................................................75 Scope ......................................................................................................................75 RB-8100 Safety Considerations .........................................................................................75 RB-8200 RB-8210 Device Data...........................................................................................................75 Device Condition .................................................................................................76 34 PART RB — INSERVICE INSPECTION OF PRESSURE-RETAINING ITEMS RB-8300 Installation Condition .........................................................................................76 RB-8400 RB-8410 Testing and Operational Inspection ..................................................................77 Recommended Inspection and Test Frequencies ............................................78 RB-8500 RB-8510 RB-8520 RB-8530 Additional Inspection Information ...................................................................80 Boilers ....................................................................................................................80 Pressure Vessels and Piping ...............................................................................81 Rupture Disks.......................................................................................................81 RB-8600 Requirements for Shipping and Transporting.................................................83 RB-8700 Inservice Inspection Activities ...........................................................................83 RB-9000 Methods for Estimating Remaining Service Life and Inspection Intervals ...........................................................................................83 Scope ......................................................................................................................83 RB-9010 RB-9100 RB-9110 RB-9120 RB-9130 RB-9140 Conditions That Affect Remaining Service Life ..............................................84 Method for Estimating Remaining Service Life for Exposure to Elevated Temperature...................................................................................84 Method for Estimating Inspection Interval for Exposure to Elevated Temperature..................................................................................85 Method for Estimating Remaining Service Life for Exposure to Corrosion ........................................................................................................85 Method for Estimating Inspection Interval for Exposure to Corrosion.......88 35 NATIONAL BOARD INSPECTION CODE RB-1000 GENERAL REQUIREMENTS FOR INSERVICE INSPECTION OF PRESSURERETAINING ITEMS RB-1010 SCOPE to the original pressure-retaining item is still possible, the Inspector shall instruct the owner or user to have the stamped data replaced. All re-stamping shall be done in accordance with the original code of construction, except A04 as modified herein. Requests for permission to re-stamp or replace nameplates shall be made to the jurisdiction in which the pressure-retaining item is installed. Application must be made on the Replacement of Stamped Data Form NB-136 (Appendix 5). Proof of the original stamping and other such data, as is available, shall be furnished with the request. Permission from the jurisdiction is not required for the reattachment of nameplates that are partially attached. When traceability cannot be established, the jurisdiction shall be contacted. Part RB provides guidelines and requirements for conducting inservice inspection and testing of pressure-retaining items and pressure relief devices. Appropriately, this Part includes precautions for the safety of inspection personnel. The safety of the Inspector is the most important aspect of any inspection activity. Understanding the potential damage/deterioration mechanisms that can affect the mechanical integrity of a pressure-retaining item and knowledge of the inspection methods that can be used to find these damage mechanisms are essential to an effective inspection. This Part includes a general discussion of various damage mechanisms and effective inspection methods. In addition, some specific guidance is given on how to estimate the remaining life of a pressure-retaining item and determine the appropriate inspection interval. RB-1020 When there is no jurisdiction, the replacement A04 of stamped data shall be authorized and witnessed by a National Board Commissioned Inspector and the completed Form NB-136 shall be submitted to the National Board. A04 Replacement of Stamped Data The restamping or replacement of data shall be witnessed by a National Board Commissioned Inspector and shall be identical to the original stamping. The restamping or replacement of a code sym- A04 bol stamp shall be done only by the original manufacturer and witnessed by a National Board Commissioned Inspector. ADMINISTRATION Jurisdictional requirements describe the frequency, scope, type of inspection, whether internal, external or both and type of documentation required for the inspection. The Inspector shall have a thorough knowledge of jurisdictional regulations where the item is installed, as inspection requirements may vary. RB-1030 Replacement nameplates shall be clearly A04 marked “replacement.” Reporting A04 Form NB-136 shall be filed with the jurisdiction (if required) or the National Board by the owner or user together with a facsimile of the stamping or nameplate, as applied, and shall also bear the signature of the National Board Commissioned Inspector who witnessed the replacement. STAMPING A04 Authorization When the stamping on a pressure-retaining item becomes indistinct or the nameplate is lost, illegible or detatched, but traceability 36 PART RB — INSERVICE INSPECTION OF PRESSURE-RETAINING ITEMS RB-1040 REFERENCE TO OTHER CODES AND STANDARDS RB-1050 During any inspections or tests of pressureretaining items, the actual operating and maintenance practices should be noted by the Inspector and a determination made as to their acceptability. Other existing inspection codes, standards and practices pertaining to the inservice inspection of pressure-retaining items can provide useful information and references relative to the inspection techniques listed in Part RB. Additionally, supplementary guidelines for assisting in the evaluation of inspection results and findings are also available. Some acceptable guidelines are as follows: Defects or deficiencies in the condition, operating and maintenance practices of the boiler, pressure vessel or piping system equipment should be discussed with the owner or user at the time of inspection and recommendations made for correction of any such defects or deficiencies. a. National Board BULLETIN – National Board Classic Articles Series b. American Society of Mechanical Engineers – ASME Boiler & Pressure Vessel Code Section V (Nondestructive Examination) RB-2000 c. American Society of Mechanical Engineers – ASME Boiler & Pressure Vessel Code Section VI (Recommended Rules for the Care and Operation of Heating Boilers) PERSONNEL SAFETY AND INSPECTION ACTIVITIES Visual examination is the basic method used A04 when conducting an inservice inspection of pressure-retaining items. Additional examination and test methods may be required at the discretion of the inspector to provide additional information to assess the condition of the pressure-retaining item. See RB-3000. d. American Society of Mechanical Engineers – ASME Boiler & Pressure Vessel Code Section VII (Recommended Guidelines for the Care of Power Boilers Subsection C6 - Inspection) RB-2010 e. American Society of Mechanical Engineers – ASME B31G (Manual for Determining the Remaining Strength of Corroded Pipelines) f. CONCLUSIONS SCOPE A proper inspection of a pressure-retaining item requires many pre-inspection planning activities including: safety considerations, an inspection plan that considers the potential damage mechanisms, selection of appropriate inspection methods and awareness of the jurisdictional requirements. This section describes pre-inspection and post-inspection activities applicable to all pressure-retaining items. Specific inspection requirements for pressure-retaining items are identified in RB-5000 for boilers, RB-6000 for pressure vessels and RB-7000 for piping. American Petroleum Institute – API 572 Inspection of Pressure Vessels g. American Petroleum Institute – API 574 Inspection Practices for Piping System Components h. American Petroleum Institute – API 579 Fitness-For-Service 37 NATIONAL BOARD INSPECTION CODE RB-2100 d. An effective energy isolation program (lock out and/or tag out) is in place and in effect that will prevent the unexpected energizing, start up or release of stored energy. PERSONNEL SAFETY Personnel safety is the joint responsibility of the owner or user and the Inspector. All applicable safety regulations shall be followed. This includes governmental, state, regional and/or local rules and regulations. Owner or user programs, safety programs of the Inspector’s employer or similar regulations also apply. In the absence of such rules, prudent and generally accepted engineering safety procedures satisfactory to the Inspector shall be employed by the owner or user. RB-2110 The Inspector shall be satisfied that a safe atmosphere exists before entering the pressure-retaining item. The oxygen content of the breathable atmosphere shall be between 19.5% and 23.5%. The Inspector shall not be permitted to enter an area if toxic, flammable or inert gases, vapors or dusts are present and above acceptable limits without appropriate personal protective equipment. This may include, among other items, protective outer clothing, gloves, eye protection and foot protection. The Inspector shall have the proper training governing the selection and use of any personal protective clothing and equipment necessary to safely perform each inspection. Particular attention shall be afforded respiratory protection if the testing of the atmosphere of the object reveals any hazards. EQUIPMENT OPERATION The Inspector should not operate equipment. Operation shall be conducted only by competent individuals familiar with the equipment and qualified to perform such tasks. RB-2120 VESSEL ENTRY REQUIREMENTS No pressure-retaining item shall be entered until it has been properly prepared for inspection. The owner or user and inspector shall determine that pressure-retaining items may be entered safely. This shall include: a. Potential hazards associated with entry into the object have been identified by the owner or user and are brought to the attention of the Inspector, along with acceptable means or methods for dealing with each of these hazards; RB-2200 INSPECTION ACTIVITIES RB-2210 PREPARATION FOR INTERNAL INSPECTION The owner or user has the responsibility to prepare a pressure-retaining item for internal inspection. Requirements of occupational safety and health regulations (federal, state, local or other), as well as the owner-user’s own program and the safety program of the Inspector’s employer are applicable. The pressure-retaining item should be prepared in the following manner or as deemed necessary by the Inspector: b. Coordination of entry into the object by the Inspector and owner or user representative(s) working in or near the object; c. If personal protective equipment is required to enter an object, the necessary equipment is available and the Inspector is properly trained in its use; a. When a vessel is connected to a common header with other vessels or in a system where liquids or gases are present, the 38 PART RB — INSERVICE INSPECTION OF PRESSURE-RETAINING ITEMS vessel shall be isolated by closing, locking and/or tagging stop valves in accordance with the owner’s or user’s procedures. When toxic or flammable materials are involved, additional safety precautions may require removing pipe sections or blanking pipelines before entering the vessel. The means of isolating the vessel shall be acceptable to the Inspector and in compliance with applicable occupational safety and health regulations and procedures. For boilers or fired pressure vessels, the fuel supply and ignition system shall be locked out and/or tagged out, in accordance with the owner or user procedures. e. The Inspector shall not enter a vessel until all safety precautions have been taken. The temperature of the vessel shall be such that the inspecting personnel will not be exposed to excessive heat. Vessel surfaces should be cleaned as necessary. f. b. The vessel shall be allowed to cool or warm at a rate to avoid damage to the vessel. When a boiler is being prepared for internal inspection, the water should not be withdrawn until it has been sufficiently cooled at a rate to avoid damage to the boiler. If requested by the Inspector or required by regulation or procedure, a responsible person (attendant) shall remain outside the vessel at the point of entry while the Inspector is inside and shall monitor activity inside and outside and communicate with the Inspector as necessary. The attendant shall have a means of summoning rescue assistance, if needed, and to facilitate rescue procedures for those inside the vessel without personally entering the vessel. NOTE: If a vessel has not been properly prepared for an internal inspection, the inspector shall decline to make the inspection. c. The vessel shall be drained of all liquid and shall be purged of any toxic or flammable gases or other contaminants that were contained in the vessel. Mechanical ventilation using a fresh air blower or fan shall be started after the purging operation and maintained until all pockets of “dead air,” which may contain toxic, flammable or inert gases are reduced to acceptable limits. During air purging and ventilation of vessels involved with flammable gases, the concentration of vapor in air may pass through the flammable range before a safe atmosphere is obtained. All necessary precautions shall be taken to eliminate the possibility of explosion or fire. RB-2220 PRE-INSPECTION ACTIVITIES Prior to conducting the inspection, a review of the known history of the pressure-retaining item and a general assessment of current conditions shall be performed. This shall include a review of information such as: a. Date of last inspection; b. Current jurisdictional inspection certificate; c. ASME Code Symbol Stamping or mark of code of construction; d. National Board and/or jurisdiction registration number; d. Manhole and hand hole plates, washout plugs, inspection plugs and any other items requested by the Inspector shall be removed; e. Operating conditions and normal contents of the vessel (discuss any unique hazards with the owner or user). 39 NATIONAL BOARD INSPECTION CODE f. Previous inspection report, operating logs and test records; classification, identification numbers, inspection intervals, date inspected, type of inspection, and test performed and any other information required by the inspection agency, jurisdiction and/or owner-user. The Inspector shall sign, date and note any deficiencies, comments or recommendations on the inspection report. The Inspector should retain and distribute copies of the inspection report, as required. g. Records of wall thickness checks, especially where corrosion or erosion is a consideration; h. Review of repairs or alterations for compliance with applicable requirements; i. j. Observation of the condition of the complete installation, including maintenance and operation, to form an opinion of the care the equipment receives; Before starting the inspection, the area should be reviewed for potential hazards such as exposure to falling objects and safety of any scaffolding. When a pressure test is to be performed, the precautions in RB-3000 should be followed. INSPECTION AND TEST METHODS RB-3010 SCOPE This part describes acceptable inspection and test methods that are available to the Inspector during inspection of pressure-retaining items. The following activities should be performed as required to support the inspection: RB-3100 a. Pressure gage should be removed for testing, unless there is other information to assess its accuracy. NONDESTRUCTIVE EXAMINATION METHODS (NDE) Listed below is a variety of nondestructive examination methods that may be employed to assess the condition of pressure-retaining items. The skill, experience and integrity of the personnel performing these examinations are essential to obtain meaningful results. The Inspector should review the methods and procedures to be employed to assure compliance with jurisdictional requirements. b. Pressure relief devices should be inspected in accordance with RB-8000. RB-2230 RB-3000 POST-INSPECTION ACTIVITIES Any defects or deficiencies in the condition, operating and maintenance practices of the pressure-retaining item and auxiliary equipment should be discussed with the owner or user and recommendations made for correction. Generally, some form of surface preparation will be required prior to use of these examination methods. When there is doubt as to the extent of a defect or detrimental condition found in a pressure-retaining item, the Inspector is cautioned to seek competent technical advice and supplemental NDE. Documentation of inspection shall contain pertinent data such as description of item, 40 PART RB — INSERVICE INSPECTION OF PRESSURE-RETAINING ITEMS RB-3110 netic lines leave the north pole of a magnet). The magnetic lines of force will reenter the test object on the other side of the discontinuity, thereby creating a south pole (magnetic lines enter the south pole of a magnet). Since a north and a south pole have been created they will attract magnetizable objects. Iron powder is placed on the discontinuity is held in place by the lines of force and will be visible on the surface of the test object. VISUAL Visual examination is an inspection method to ascertain the surface condition of the pressure-retaining item. The Inspector should be aware of recognizing various surface features and comparing these features with damage mechanisms listed in RB-4000 that could indicate exposure of the pressure-retaining item to harmful corrosion or elevated temperature service. In some cases the Inspector may have limited or no access while performing an inspection of the pressure-retaining item. Subject to approval of the jurisdiction, remote camera or fiber optic devices may be considered acceptable methods to view and record the surface condition of the pressure-retaining item. RB-3120 RB-3130 LIQUID PENETRANT The liquid penetrant examination method is used to detect discontinuities that are open to the surface of the material being examined. This method may be used on both ferrous and nonferrous materials. Liquid penetrant examination may be used for the detection of surface discontinuities such as cracks, seams, laps, cold shuts, laminations and porosity. MAGNETIC PARTICLE The magnetic particle examination method can be used only on ferromagnetic materials to reveal surface discontinuities and to a limited degree, those located below the surface. It uses the principle that magnetic lines of force will attract magnetizable material. The sensitivity of this method decreases rapidly with depth below the surface being examined and, therefore, it is used primarily to examine for surface discontinuities. Liquid penetrant examination works by applying a colored liquid (penetrant) to the object to be examined. Time is allowed for the liquid to fill any voids that are open to the surface. Excess penetrant is then removed and a “developer” is applied in a uniform, thin coating. The developer acts as a blotter and draws the penetrant out of the discontinuity. The developer is usually of a contrasting color to the penetrant. The penetrant indications will appear as colored figures on a background of the developer. In order to use this method, a magnetic field has to be established within the material to be examined. This can be done directly by bringing a strong magnetic field into close proximity of the item being examined or by inducing a magnetic field in the object by passing electric current through the object. Liquid penetrant examination is portable, fast and requires minimal operator training. RB-3140 If there is a discontinuity at or near the surface, it will deflect the magnetic lines of force out of the object, thus creating a north pole (mag- ULTRASONIC Ultrasonic testing is used for volumetric examination of welds and base materials (metallic and non-metallic) for detection of 41 NATIONAL BOARD INSPECTION CODE flaws. This method depends on sound waves of very high frequency being transmitted through metal and reflected at any boundary, such as a metal to air boundary at the surface of the metal, or metal crack boundary at a discontinuity. High frequency sound waves can detect small irregularities but are easily absorbed, particularly by coarse-grained materials. Sound waves can be introduced into a part either normal to the surface or at predetermined angles. Factors such as material composition, surface condition, choice of equipment and ability of the operator affect the results of ultrasonic inspection. Ultrasonic testing can also be used to measure material thickness. RB-3150 Most discontinuities (cracks, porosity and inclusions) reduce the amount of base material available to absorb (attenuate) x-rays or gamma rays, thus allowing more energy to pass through the material. Most discontinuities will appear as dark shapes on the radiographic film. The technique used for radiography depends largely on the equipment used and what experience has shown will produce the best results. It is not the function of the technician to indicate the procedure to be followed, provided the procedure and films satisfy all requirements of the applicable section of the ASME Code. The radiographic film provides a permanent record of the results of the examination. RADIOGRAPHY Radiography is a volumetric method that can detect discontinuities throughout a material. This method is commonly used to examine for surface and subsurface discontinuities. The use of this method may be restricted due to the configuration of the welded joint or the limitations of the radiographic equipment. Radiography will not give an indication of the depth of discontinuity unless special procedures are used. RB-3160 EDDY CURRENT Examination method that measures changes in a magnetic field caused by discontinuities. Eddy current can also detect a loss of material on inaccessible surfaces and be used to detect changes in hardness of a material. There are three general types of eddy current coils: the concentric coil which surrounds the part to be tested (e.g., tubing); the probe coil which is brought adjacent to the part to be tested; and the bobbin coil which is inserted into the part to be tested (e.g., tubing). The method uses a high energy gamma ray or x-ray source to penetrate the material to be examined. The rays are absorbed, reflected and refracted by the material but some of the energy passes completely through. The energy of rays that pass completely through is determined by the thickness and other physical properties of the material. RB-3170 METALLOGRAPHIC Method of locally polishing, etching and viewing the surface of a pressure-retaining item with either acetate tape (e.g., replication) or a field microscope to determine the condition of the metal microstructure. Radiography uses film to detect the rays which penetrate the material. The higher the energy of the rays, the darker the film will become, similar to exposing photographic film to sunlight. 42 PART RB — INSERVICE INSPECTION OF PRESSURE-RETAINING ITEMS RB-3180 remaining service life of the component due to causing permanent deformation of the item. ACOUSTIC EMISSION Acoustic emission is a method of detecting and monitoring discontinuities in a pressureretaining item or load-bearing structure. This method utilizes wave guides, transducers, cables and a sophisticated data acquisition system to collect transient acoustic emissions generated by the rapid release of energy from localized sources within the material being tested. Signal amplitude, frequency and location are collected for many hours of operation at various loads or pressures. Analysis of the data can determine if any part of the system requires additional nondestructive examination with a more sensitive test method. RB-3200 If an inservice pressure test is required, the following precautions shall be met: a. The test pressure should not exceed 90% of the set pressure of the lowest setting pressure relief device on the component to avoid damage to pressure relief devices. b. Test pressure should be selected or adjusted in agreement between the Inspector and the owner-user. When the original test pressure includes consideration of corrosion allowance, the test pressure may be further adjusted based upon the remaining corrosion allowance. TESTING c. The metal temperature during a pressure test should not be less than 60°F (16°C) unless the owner-user provides information on the toughness characteristics of the vessel material to indicate the acceptability of a lower test temperature. All testing should be performed by experienced personnel using written procedures acceptable to the Inspector. RB-3210 PRESSURE TESTING d. The metal temperature shall not be more than 120°F (50°C) unless the owner-user specifies the requirement for a higher test temperature. If the owner-user specifies a test temperature higher than 120°F (50°C), then precautions shall be taken to afford the Inspector close examination without risk of injury. During an inspection of a pressure-retaining item, there may be certain instances where inservice conditions have adversely affected the tightness of the component or the inspection discloses unusual, hard to evaluate forms of deterioration that may affect the safety of the vessel. In these specific instances, a pressure test using air, water or other suitable test A04 medium may be required at the discretion of the Inspector to assess leak tightness of the pressure-retaining item. e. When contamination of the vessel contents by any medium is prohibited or when a pressure test is not practical, other testing methods described below may be used provided the precautionary requirements of the applicable section of the original construction code or other standards are followed. In such cases, there shall be agreement as to the testing procedure between the owner-user and the Inspector. The Inspector is cautioned that a pressure test will not provide any indication of the amount of remaining service life or the future reliability of a pressure-retaining item. The pressure test in this instance only serves to determine if the pressure-retaining item contains defects which will not allow the item to retain pressure. In certain instances, pressure tests of inservice components may reduce the 43 NATIONAL BOARD INSPECTION CODE RB-3220 LEAK TESTING RB-4020 Leak testing for the purpose of detecting any leakage may be performed when a pressure test cannot be performed. Some methods or techniques for leak testing may include bubble test (direct pressure or vacuum), helium mass spectrometer, pressure change or flow measurement. Use of leak test procedures shall be in agreement between the owner-user and the Inspector. Use of written procedures and experienced personnel is required when performing leak tests. The Inspector shall review the written procedure to become familiar with limitations, adequacy, methods and acceptance standards identified. RB-3300 All metals and alloys are susceptible to corrosion. Corrosion is deterioration that occurs when a metal reacts with its environment. Corrosion can be classified based on three factors: a. Nature wet – liquid or moisture present dry – high temperature gasses b. Mechanism – electrochemical or direct chemical reactions c. Appearance – either uniform or localized MATERIAL PREPARATION – GENERAL GUIDELINES Materials to be inspected shall be suitably prepared so surface irregularities will not be confused with or mask any defects. Material conditioning such as cleaning, buffing, wire brushing or grinding may be required by procedure or, if requested, by the Inspector. Insulation or component parts may be required by the Inspector to be removed. RB-4000 CAUSES OF DETERIORATION AND FAILURE MECHANISMS RB-4010 SCOPE GENERAL RB-4100 CORROSION RB-4110 MACROSCOPIC CORROSION ENVIRONMENTS Macroscopic corrosion types are among the most prevalent conditions found in pressureretaining items causing deterioration. The following corrosion types are found. a. Uniform Corrosion (General) The most common form of corrosion is the uniform attack over a large area of the metal surface. Safe working pressure is directly related to the remaining material thickness and failures can be avoided by regular inspection. This section describes causes of deterioration such as corrosion and erosion and failure mechanisms such as cracking, fatigue, creep and temperature gradients that are applicable to pressure-retaining items. Further information concerning metallurgical properties of steels and nonferrous alloys are described in ASME Section II, Part D, of the Boiler and Pressure Vessel Code, Appendix 6, titled Metallurgical Phenomena. b. Galvanic Corrosion Two dissimilar metals in contact with each other and with an electrolyte (i.e., a film of water containing dissolved oxygen, nitrogen and carbon dioxide) constitute 44 PART RB — INSERVICE INSPECTION OF PRESSURE-RETAINING ITEMS an electrolyte cell, and the electric current flowing through the circuit may cause rapid corrosion of the less noble metal (the one having the greater electrode potential). This corrosion mechanism is most active when there are large differences between the electrode potentials of the two metals, but galvanic corrosion may also exist with relatively minor changes of alloy composition (i.e., between a weld metal and the base metal). Natural (i.e., an oxide coating on aluminum) or protective coatings may inhibit galvanic corrosion, but in most instances the metals or alloys must be selected on the basis of intrinsic resistance to corrosion. In pressure vessels the effects of galvanic corrosion are most noticeable at rivets welds, or at flanged and bolted connections. 3. Buildup of detrimental ions in the crevice; 4. Depletion of a corrosion inhibitor in the crevice. e. Pitting Corrosion Pitting corrosion is the formation of holes in an otherwise relatively unattacked surface. Pitting is usually a slow process causing isolated, scattered pitting over a small area that does not substantially weaken the vessel. It could, however, eventually cause leakage. f. c. Erosion Corrosion Movement of a corrodent over a metal surface increases the rate of attack due to mechanical wear and corrosion. This corrosion is generally characterized as having an appearance of smooth bottomed shallow pits and may also exhibit a directional pattern related to the path taken by the corrodent. Line Corrosion This is a condition where pits are connected, or nearly connected, to each other in a narrow band or line. Line corrosion frequently occurs in the area of intersection of the support skirt and the bottom of the vessel or liquid-vapor interface. g. Exfoliation and Selective Leaching Exfoliation is a subsurface corrosion that begins on a clean surface but spreads below it. It differs from pitting in that the attack has a laminated appearance. These attacks are usually recognized by a flaky and sometimes blistered surface. d. Crevice Corrosion Environmental conditions in a crevice can, with time, become different to those on a nearby clean surface. A more aggressive environment may develop within the crevice and cause local corrosion. Crevices commonly exist at gasket surfaces, lap joints, bolts, rivets, etc. They are also created by dirt deposits, corrosion products, scratches in paint, etc. Crevice corrosion is usually attributed to one or more of the following: Selective leaching is the removal of one element in an alloy. This corrosion mechanism is detrimental because it yields a porous metal with poor mechanical properties. h. Grooving This type of corrosion is a form of metal deterioration caused by localized corrosion and may be accelerated by stress concentration. Grooving may be found adjacent to riveted lap joints or welds and on flanged surfaces, particularly the flanges of unstayed heads. 1. Changes in aciditiy in the crevice; 2. Lack of oxygen in the crevice; 45 NATIONAL BOARD INSPECTION CODE RB-4120 itic stainless steels used in water wetted service are susceptible to stress corrosion cracking. MICROSCOPIC CORROSION ENVIRONMENTS Microscopic corrosion environments are not visible to the naked eye. The following corrosion types are among the most prevalent conditions found in pressure-retaining items causing deterioration. c. Corrosion Fatigue This is a special form of stress corrosion cracking caused by repeated cyclic stressing. When fatigue is in the presence of a corrodent, the resulting failure is corrosion fatigue. Such failures are common to pressure-retaining items subjected to continued vibration. a. Intergranular Corrosion Corrosion attack by a corrodent is usually relating to the segregation of specific elements or the formation of a compound in the grain boundary. It usually attacks the grain boundary that has lost an element necessary for adequate corrosion resistance. In severe cases entire grains are dislodged causing the surface to appear rough to the naked eye and will feel sugary because of the loose grains. Susceptibility to intergranular corrosion is usually a by-product of heat treatment. RB-4200 CONTROL OF CORROSION There are many ways to control and avoid corrosion such as control of process variables, engineering design, protection, material selection, and coatings. RB-4210 PROCESS VARIABLES b. Stress Corrosion Cracking The action of tensile stress and a corrodent results in the cracking of metals. This is most serious because periods of time (often years) may pass before cracks become visible. The cracks then propagate quite rapidly and result in unexpected failures. Stresses that cause cracking arise from cold working, welding, thermal treatment or may be externally applied during service. The cracks can follow intergranular or transgranular paths and often have a tendency for branching. Some of the more common process variables that influence corrosion are listed below: The principal variables affecting stress corrosion cracking are tensile stress, service temperature, solution chemistry, duration of exposure and metal properties. Modifying any one of these parameters sufficiently can reduce or eliminate the possibility of stress corrosion cracking occurring in service. As an example, austen- Crevice, galvanic, erosion and stress corrosion cracking are the types of corrosion most controllable by proper design of equipment. Procedures and situations such as welding, end-grain attack and drainage are also controlled by proper design techniques. • • • • • • • Concentration of major constituents Impurities Temperature pH Velocity Inhibitors Startup and downtime operations RB-4220 46 ENGINEERING DESIGN PART RB — INSERVICE INSPECTION OF PRESSURE-RETAINING ITEMS RB-4230 Inorganic coatings would include: PROTECTION Protective methods such as cathodic and anodic corrosion control can minimize attack and thereby reduce replacement costs or permit the use of less expensive or thinner materials. RB-4240 • • • • • • MATERIAL SELECTION RB-4300 Chemical and physical properties of a material will enable selection of the best one for a specific application. The final choice will often be a compromise between the desired physical properties and economic factors. A checklist for material selection would include: • • • • • • • • • • • Poor choice of materials Operating conditions different from those anticipated Defective fabrication Improper design Inadequate maintenance Defective material Corrective actions will depend on which factors caused the problems making it important to diagnose the reason for failure. Early detection of corrosion problems is important to prevent failures and can be achieved by performing regular inspections and encouraging employees to be observant and communicate their observations. COATINGS Metallic and inorganic materials are typical coatings for controlling corrosion. Selection of materials depends on the corrodent, method of application, type of base material and the nature of bonding between the base material and coating. The success or failure of a coating will often depend on the surface preparation. Techniques for applying metallic coatings could include: • • • • • • • • CONCLUSION By carefully selecting materials and protection methods, we can predict and control corrosive attack. However, there may be unexpected failures as a result of one or more of the following: Evaluating requirements to be met (properties, design, appearance, mechanical, physical) Material selection considerations Corrodent variables Application of equipment Experience of materials RB-4250 Porcelain, ceramic Glass Cement Rubber Paint Phosphates Hot dipping Metal spraying Cladding Cementation Vapor deposition Electroplating Plating Welding RB-4400 FAILURE MECHANISMS RB-4410 FATIGUE Stress reversals (such as cyclic loading) in parts of equipment are common, particularly at points of high secondary stress. If stresses are high and reversals frequent, failure of parts may occur because of fatigue. Fatigue failures in pressure vessels may also result from cyclic 47 NATIONAL BOARD INSPECTION CODE temperature and pressure changes. Locations where metals having different thermal coefficients of expansion are joined by welding may be susceptible to thermal fatigue. RB-4420 RB-4440 Hydrogen attack occurs in a high-temperature, high-pressure hydrogen environment that can degrade the mechanical strength of carbon steels and low alloy steels. This type of damage is called hydrogen attack. It is caused by hydrogen permeating the steel and reacting with carbon to form methane. Since carbon is a strengthening agent in steel, its removal by the reaction with hydrogen causes the steel to lose strength. In addition, methane can become trapped within the steel at high pressures, eventually forming bubbles, fissures (cracks) and/or blisters. CREEP Creep may occur if equipment is subjected to temperatures above those for which the equipment is designed. Since metals become weaker at higher temperatures, such distortion may result in failure, particularly at points of stress concentration. If excessive temperatures are encountered, structural property and chemical changes in metals may also take place, which may permanently weaken equipment. Since creep is dependent on time, temperature and stress, the actual or estimated levels of these quantities should be used in any evaluations. RB-4430 HYDROGEN ATTACK Damage caused by hydrogen attack is preceded by an incubation period with no noticeable change in properties. After the incubation period, decarburization and/or blistering and fissuring will occur. The length of the incubation period varies with temperature, pressure and alloy content of the steel. Damage is reversible during the incubation period, during which no loss of mechanical properties will have occurred. Once permanent degradation begins, the damage is irreversible. TEMPERATURE At subfreezing temperatures, water and some chemicals handled in pressure vessels may freeze and cause failure. Carbon and low alloy steels may be susceptible to brittle failure at ambient temperatures. A number of failures have been attributed to brittle fracture of steels that were exposed to temperatures below their transition temperature and that were exposed to pressures greater than 20% of the required hydrostatic test pressure. However, most brittle fractures have occurred on the first application of a particular stress level (that is, the first hydrostatic test or overload). Special attention should be given to low alloy steels because they are prone to temper embrittlement. Temper embrittlement is defined as a loss of ductility and notch toughness due to postweld heat treatment or high temperature service, above 700°F (370°C). Hydrogen attack is a concern primarily in refinery and petrochemical plant equipment handling hydrogen and hydrogen-hydrocarbon streams at temperatures above about 450°F (230°C) and pressures above 100 psi (700 kPa). A guideline for selection of steels to avoid hydrogen attack is given in API Publication 941, “Steels for Hydrogen Service at Elevated Temperatures and Pressures in Petroleum Refineries and Petrochemical Plants.” Also widely known as the “Nelson Curves,” API 941 shows that the severity of hydrogen attack depends on temperature, hydrogen partial pressure, exposure time and steel composition. Additions of chromium and molybdenum to the steel composition increase resistance to hydrogen attack. 48 PART RB — INSERVICE INSPECTION OF PRESSURE-RETAINING ITEMS It is important to understand that hydrogen attack is different from hydrogen embrittlement, which is discussed next. Hydrogen attack occurs in the absence of liquid water at elevated temperatures (above 450°F [230°C]). Hydrogen embrittlement primarily occurs as a result of corrosion reactions occurring in aqueous solutions at temperatures generally below about 200°F (95°C). RB-4450 strength steels are more susceptible. The strength level at which susceptibility arises depends on the severity of the environment that the steel is exposed to. Hydrogen sulfide, hydrogen cyanide and arsenic, in aqueous solutions, all greatly increase the severity of the environment towards hydrogen embrittlement by increasing the amount of hydrogen that is absorbed by the steel during the corrosion reaction. In hydrogen sulfide environments, cracking can generally be avoided by using steels with a strength level below that equivalent to a hardness of Rockwell C-22. HYDROGEN EMBRITTLEMENT Hydrogen embrittlement is a loss of strength and/or ductility in steels caused by atomic hydrogen dissolved in the steel. It is a low temperature phenomenon, seldom encountered above 200°F (95°C), and most often occurs as a result of hydrogen evolved from aqueous corrosion reactions. It can vary in its appearance and can occur in differing environments, thus giving rise to the various terms by which it is known, including sulfide stress cracking, wet hydrogen sulfide cracking, hydrogen stress cracking, blistering, blister cracking, hydrogen-induced cracking (HIC), stress-oriented hydrogen-induced cracking (SOHIC) and others. Weld underbead cracking (also known as delayed cracking and cold cracking) is also a form of hydrogen embrittlement, however in this case, the hydrogen comes from the welding operation rather than from a corrosion reaction. Similarly, weld underbead cracking is caused by hydrogen dissolved in a hard, high strength, weld-heat-affected zone. Use of low hydrogen welding practice to minimize dissolved hydrogen, and/or use of high preheat and/or postweld heat treatment to reduce heat-affected-zone hardness, will reduce the likelihood of weld underbead cracking in a susceptible steel. Hydrogen embrittlement is reversible as long as no physical damage, e.g., cracking, has occurred in the steel. If the atomic hydrogen is removed from the steel before any damage occurs, for example, by heating for a short time in the absence of hydrogen to between 300°F (150°C) and 400°F (205°C), normal mechanical properties will be restored. Cracking that can occur in vessels operating in aqueous hydrogen sulfide service (i.e., wet hydrogen sulfide cracking) will not always be readily apparent upon visual inspection. Other methods, such as magnetic particle (including wet fluorescent) or liquid penetrant, may be required to reveal the cracks. Some forms of hydrogen embrittlement require an applied stress or residual stress for cracking to occur (sulfide stress cracking, SOHIC, weld underbead cracking), while others occur in the absence of applied or residual stress, the internal pressure from the recombined hydrogen gas being sufficient to cause the damage (blistering, HIC). Welding procedures, repair methods and inspection procedures must include careful consideration of potential failure in corrosive environments, including the various forms of hydrogen embrittlement. Susceptibility to sulfide stress cracking and similar forms of hydrogen embrittlement depends on the strength of the steel. Higher 49 NATIONAL BOARD INSPECTION CODE RB-4460 Cracks noted in shell plates and fire cracks that run from the edge of the plate into the rivet holes of girth seams should be repaired. Thermal fatigue cracks determined by engineering evaluation to be self arresting may be left in place. BULGES AND BLISTERS A bulge may be caused by overheating of the entire thickness of the metal, thereby lowering the strength of the metal which is then deformed by the pressure. Bulges may also be caused by creep or temperature gradients. Areas where cracks are most likely to appear should be examined. This includes the ligaments between tube holes, from and between rivet holes, any flange where there may be repeated flexing of the plate during operation and around welded connections. A blister may be caused by a defect in the metal, such as a lamination, where the side exposed to the fire overheats but the inner side retains its strength due to cooling effect of water or other medium. Blisters may also be caused by a hydrogen environment. See RB-4450. RB-4470 Lap joints are subject to cracking where the plates lap in the longitudinal seam. If there is any evidence of leakage or other distress at this point, the Inspector shall thoroughly examine the area and, if necessary, have the plate notched or slotted in order to determine whether cracks exist in the seam. Repairs of lap joint cracks on longitudinal seams are prohibited. OVERHEATING Overheating is one of the most serious causes of deterioration. Deformation and possible rupture of pressure parts may result. Particular attention should be given to surfaces exposed to fire. It should be observed whether any part has become deformed due to bulging or blistering. If a bulge or blister reduces the integrity of the component or when evidence of leakage is noted coming from those defects, proper repairs must be made. RB-4480 Where cracks are suspected, it may be necessary to subject the pressure-retaining item to nondestructive examination to determine their location. RB-4500 SPECIFIC INSPECTION REQUIREMENTS Specific inspection requirements for pressureretaining items to determine corrosion deterioration and possible prevention of failures are identified in RB-5000 for boilers, RB-6000 for pressure vessels, and RB-7000 for piping. CRACKS Cracks may result from flaws existing in material. The design and operating conditions may also cause cracking. Cracking can be caused by fatigue of the metal due to continual flexing and may be accelerated by corrosion. Fire cracks are caused by the thermal differential when the cooling effect of the water is not adequate to transfer the heat from the metal surfaces exposed to the fire. Some cracks result from a combination of all these causes mentioned. RB-5000 INSPECTION OF BOILERS RB-5010 SCOPE This section provides guidelines for external and internal inspection of boilers used to con- 50 PART RB — INSERVICE INSPECTION OF PRESSURE-RETAINING ITEMS tain pressure. This pressure may be obtained from an external source or by the application of heat from a direct or indirect source or a combination thereof. RB-5100 ventilation for habitability, combustion air, housekeeping, personal safety and general safety considerations. GENERAL CONDITIONS Boilers are designed for a variety of service conditions. The temperature and pressure at which they operate should be considered in establishing inspection criteria. This part is provided for guidance of a general nature. There may be occasions where more detailed procedures will be required. RB-5400 INSPECTIONS RB-5410 EXTERNAL INSPECTION The external inspection of a boiler is made to determine if it is in a condition to operate safely. Some items to consider are: a. The boiler fittings, valves and piping should be checked for compliance with ASME Code or other standards or equivalent requirements; The condition of the complete installation, including maintenance and operation, can often be used by the Inspector as a guide in forming an opinion of the care given to the boiler. b. Adequacy of structure, boiler supports and any associated support steel; Usually the conditions to be observed by the Inspector are common to both power and heating boilers, however, where appropriate, the differences are noted. c. Boiler casing should be free from cracks, combustion gas or fluid leaks, excessive corrosion or other degradation that could interfere with proper operation; PRE-INSPECTION ACTIVITIES d. Soot blowers, valving and actuating mechanisms; A review of the known history of the boiler shall be performed. This shall include a review of information contained in RB-2000 and other items listed below. e. Gaskets on observation doors, access doors, drums, handhole and manhole covers and caps; RB-5200 f. Valves and actuators, either chains, motors and/or handwheels; RB-5300 CONDITION OF INSTALLATION g. Leakage of fluids or combustion gases. RB-5310 GENERAL RB-5420 The general condition of the boiler room or boiler location should be assessed using appropriate jurisdictional requirements and overall engineering practice. Items that are usually considered are lighting, adequacy of INTERNAL INSPECTION When a boiler is to be prepared for internal inspection, the water shall not be withdrawn until the setting has been sufficiently cooled at a rate to avoid damage to the boiler as well as additional preparations identified in RB-2120 and RB-2210. 51 NATIONAL BOARD INSPECTION CODE For additional information regarding a leak in a boiler or the extent of a possible defect, a pressure test may be required. The owner or user shall prepare a boiler for internal inspection in the following manner: Before opening the manhole(s) and entering any part of the boiler that is connected to a common header with other boilers, the required steam or water system stop valves (including bypass) must be closed, locked out and/or tagged in accordance with the owneruser’s procedures and drain valves or cocks between the two closed stop valves opened. After draining the boiler, the blowoff valves shall be closed, locked out and/or tagged out in accordance with the owner-user’s procedures. Alternatively, lines may be blanked or sections of pipe removed. Blowoff lines, where practicable, shall be disconnected between pressure parts and valves. All drains and vent lines shall be open. a. To determine tightness, the test pressure need be no greater than the maximum allowable working pressure stamped on the pressure-retaining item. b. During a pressure test where the test pressure will exceed the set pressure of a pressure relief device, the device shall be prepared as recommended by the valve manufacturer. c. The temperature of the water used to apply a pressure test should not be less than 70°F (20°C) and the maximum temperature during inspection should not exceed 120°F (50°C). A lower water temperature could be used if the owner can provide information on the toughness characteristics of the material to indicate acceptability of the lower test temperature. The Inspector shall review all personnel safety requirements as outlined in RB-2000 prior to entry. NOTE: If a boiler has not been properly prepared for an internal inspection, the inspector shall decline to make the inspection. d. Hold-time for the pressure test shall be 10 minutes prior to the examination by the Inspector. e. Hold-time for the examination by the Inspector shall be the time necessary for the Inspector to conduct the inspections. RB-5430 EVIDENCE OF LEAKAGE It is not normally necessary to remove insulating material, masonry, or fixed parts of a boiler for inspection, unless defects or deterioration are suspected or are commonly found in the particular type of boiler being inspected. Where there is evidence of leakage showing on the covering, the Inspector shall have the covering removed in order that a thorough inspection of the area may be made. Such inspection may require removal of insulating material, masonry or fixed parts of the boiler. f. 52 When the introduction of water for a hydrostatic test will cause damage to a boiler or boiler component, other testing media or vacuum testing may be used provided the precautionary requirements of the applicable section of the original code of construction or other standards are followed. In such cases, there shall be agreement as to the testing procedure between the owner and the Inspector. PART RB — INSERVICE INSPECTION OF PRESSURE-RETAINING ITEMS RB-5500 INSPECTION REQUIREMENTS — GENERAL (See RB-4000) amine as much area as possible. Other means of examination such as the ultrasonic method may be employed. RB-5510 CORROSION Grooving is usually progressive and when it is detected, its effect should be carefully evaluated and corrective action taken. Corrosion causes deterioration of the metal surfaces. It can affect large areas or it can be localized in the form of pitting. Isolated, shallow pitting is not considered serious if not active. The fireside surfaces of tubes in horizontal firetube boilers usually deteriorate more rapidly at the ends nearest the fire. The Inspector should examine the tube ends to determine if there has been serious reduction in thickness. The tube surfaces in some vertical tube boilers are more susceptible to deterioration at the upper ends when exposed to the heat of combustion. These tube ends should be closely examined to determine if there has been a serious reduction in thickness. The upper tube sheet in a vertical “dry top” boiler should be inspected for evidence of overheating. The most common causes of corrosion in boilers are the presence of free oxygen and dissolved salts in the feedwater. Where active corrosion is found, the Inspector should advise the owner or user to obtain competent advice regarding proper feedwater treatment. For the purpose of estimating the effect of severe corrosion over large areas on the safe working pressure, the thickness of the remaining sound metal should be determined by ultrasonic examination or by drilling. Pitting and corrosion on the waterside surfaces of the tubes should be examined. In vertical firetube boilers, excessive corrosion and pitting is often noted at and above the water level. Grooving is a form of metal deterioration caused by localized corrosion and may be accelerated by stress concentration. This is especially significant adjacent to riveted joints. The surfaces of tubes should be carefully examined to detect corrosion, erosion, bulges, cracks or evidence of defective welds. Tubes may become thinned by high velocity impingement of fuel and ash particles or by the improper installation or use of soot blowers. A leak from a tube frequently causes serious corrosion or erosion on adjacent tubes. All flanged surfaces should be inspected, particularly the flanges of unstayed heads. Grooving in the knuckles of such heads is common since there is slight movement in heads of this design which causes a stress concentration. In restricted fireside spaces, such as where short tubes or nipples are used to join drums or headers, there is a tendency for fuel and ash to lodge at junction points. Such deposits are likely to cause corrosion if moisture is present and the area should be thoroughly cleaned and examined. Some types of boilers have ogee or reversedflanged construction which is prone to grooving and may not be readily accessible for examination. The Inspector should insert a mirror through an inspection opening to ex- 53 NATIONAL BOARD INSPECTION CODE RB-5520 INSPECTION OF PIPING, PARTS, AND APPURTENANCES RB-5521 BOILER PIPING to make the test more effective. An unbroken bolt should give a ringing sound while a broken bolt will give a hollow or non-responsive sound. Staybolts with telltale holes should be examined for evidence of leakage, which will indicate a broken or cracked bolt. Broken staybolts shall be replaced. Piping should be inspected in accordance with RB-7000. RB-5522 RB-5524 WATERSIDE DEPOSITS The manhole and reinforcing plates, as well as nozzles or other connections flanged or bolted to the boiler, should be examined for evidence of defects both internally and externally. Whenever possible, observation should be made from both sides, internally and externally, to determine whether connections are properly made to the boiler. All accessible surfaces of the exposed metal on the waterside of the boiler should be inspected for deposits caused by water treatment, scale, oil or other substances. Oil or scale in the tubes of watertube boilers is particularly detrimental since this can cause an insulating effect resulting in overheating, weakening and possible metal fatigue by bulging or rupture. All openings leading to external attachments, such as water column connections, low water fuel cut-off devices, openings in dry pipes and openings to safety valves, should be examined to ensure they are free from obstruction. Excessive scale or other deposits should be removed by chemical or mechanical means. RB-5523 FLANGED OR OTHER CONNECTIONS STAYS AND STAYBOLTS RB-5525 MISCELLANEOUS All stays, whether diagonal or through, A04 should be inspected to determine whether or not they are in even tension. Staybolt ends and the stayed plates should be examined to determine whether cracks exist. In addition, stayed plates should be inspected for bulging in the general area of the stay. Each staybolt end should be checked for excessive cold working (heading) and seal welds as evidence of a possible leakage problem. Stays or staybolts which are not in tension or adjustment should be repaired. Broken stays or staybolts shall be replaced. The piping to the water column should be carefully inspected to ensure that water cannot accumulate in the steam connection. The position of the water column should be checked to determine that the column is placed in accordance with ASME Code or other standard or equivalent requirements. The gas side baffling should be inspected. The absence of the proper baffling or defective baffling can cause high temperatures and overheat portions of the boiler. The location and condition of combustion arches should be checked for evidence of flame impingement, which could result in overheating. The Inspector should test firebox staybolts by tapping one end of each bolt with a hammer and, where practicable, a hammer or other heavy tool should be held on the opposite end 54 PART RB — INSERVICE INSPECTION OF PRESSURE-RETAINING ITEMS Any localization of heat caused by improper or defective installation or improper operation of firing equipment should be corrected before the boiler is returned to service. RB-5526 GAGES The refractory supports and settings should be carefully examined, especially at points where the boiler structure comes near the setting walls or floor, to ensure that deposits of ash or soot will not bind the boiler and produce excessive strains on the structure due to the restriction of movement of the parts under operating conditions. a. Close the lower gage glass valve then open the drain cock and blow the glass clear. Ensure that the water level indicated is correct by having the gage tested as follows: b. Close the drain cock and open the lower gage glass valve. Water should return to the gage glass immediately. c. Close the upper gage glass valve then open the drain cock and allow the water to flow until it runs clean. When tubes have been rerolled or replaced, they should be inspected for proper workmanship. Where tubes are readily accessible, they may have been over rolled. Conversely, when it is difficult to reach the tube ends they may have been under rolled. d. Close the drain cock and open the upper gage glass valve. Water should return to the gage glass immediately. If the water return is sluggish, the test should be discontinued. A sluggish response could indicate an obstruction in the pipe connections to the boiler. Any leakage at these fittings should be promptly corrected to avoid damage to the fittings or a false waterline indication. Drums and headers should be inspected internally and externally for signs of leakage, corrosion, overheating and erosion. Inspect blowdown piping and connections for expansion and flexibility. Check header seals for gasket leakage. Soot blower mechanical gears, chains, pulleys, etc. should be checked for broken or worn parts. Inspect supply piping to the soot blowers for faulty supports, leakage and expansion and contraction provisions. Check design for proper installation to allow for complete drainage of condensate which may cause erosion. Each hot water boiler should be fitted with a temperature gage at or near the boiler outlet that will at all times indicate the water temperature. Where required, all the pressure gages shall be removed, tested, and their readings compared to the readings of a standard test gage or a dead weight tester. Valves should be inspected on boiler feedwater, blowdown, drain and steam systems for gland leakage, operability, tightness, handle or stem damage, body defects and general corrosion. The location of a steam pressure gage should be noted to determine whether it is exposed to high temperature from an external source or to internal heat due to lack of protection by a proper siphon or trap. The Inspector should check that provisions are made for blowing out the pipe leading to the steam gage. 55 NATIONAL BOARD INSPECTION CODE The pressure indicated on the pressure gage should be compared with other gages on the same system or with a standard test gage, if necessary. The Inspector should observe the reading during tests; for example, the reduction in pressure when testing the low water fuel cutoff control or safety valve on steam boilers. Defective gages should be promptly replaced. should be taken out of service until the unsafe condition has been corrected. See RB-8000 for the inspection of safety devices (pressure relief valves) used to prevent overpressure of boilers. All automatic low water fuel cut-off and water feeding devices should be examined by the Inspector to ensure that they are properly installed. The Inspector should have the float chamber types of control devices disassembled and the float linkage and connections examined for wear. The float chamber should be examined to ensure that it is free of sludge or other accumulation. Any necessary corrective action should be taken before the device is placed back into service. The Inspector should check that the operating instructions for the devices are readily available. RB-5528 CONTROLS Check that the following controls/devices are provided: RB-5527 PRESSURE RELIEF DEVICES Verify operation of low water protection devices by observing the blowdown of these controls or the actual lowering of boiler water level under carefully controlled conditions with the burner operating. This test should shut off the heat source to the boiler. The return to normal condition such as the restart of the burner, the silencing of an alarm or stopping of a feed pump should be noted. A sluggish response could indicate an obstruction in the connections to the boiler. a. Each automatically fired steam boiler is protected from over pressure by not less than two pressure operated controls, one of which may be an operating control. b. Each automatically fired hot water boiler is protected from over-temperature by not less than two temperature operated controls, one of which may be an operating control. c. Each hot water boiler is fitted with a thermometer that will, at all times, indicate the water temperature at or near the boiler outlet. The operation of a submerged low water fuel cutoff mounted directly in a steam boiler shell should be tested by lowering the boiler water level carefully. This should be done only after being assured that the water level gage glass is indicating correctly. RB-5529 RECORDS REVIEW On a high-temperature water boiler, it is often not possible to test the control by cutoff indication, but where the control is of the float type externally mounted, the float chamber should be drained to check for the accumulation of sediment. A review of the boiler log, records of maintenance and feedwater treatment should be made by the Inspector to ensure that regular and adequate tests have been made on the boiler and controls. The owner or user should be consulted regarding repairs or alterations, if any, which have been made since the last inspection. Such In the event controls are inoperative or the correct water level is not indicated, the boiler 56 PART RB — INSERVICE INSPECTION OF PRESSURE-RETAINING ITEMS repairs or alterations should be reviewed for compliance with the jurisdictional requirements, if applicable. RB-5600 RB-5602 A04 Boilers of this type are used in the pulp and A04 paper industry. Black liquor is a by-product of pulping processing. It contains organic and inorganic constituents and is concentrated from about 10% solids to at least 58% solids for firing in the recovery boilers. The organic material that is dissolved in the pulping process combusts and the spent pulping chemicals form a molten pool in the furnace. The molten material, or “smelt,” drains from the furnace wall through smelt spouts into a smelt dissolving tank for recovery of the chemicals. Ultimately, the by-product of the recovery process is steam used for processing and power. Gas or oil auxilliary burners are used to start the self-sustaining black liquor combustion process and may be used to produce supplemental steam if sufficient liquor is not available. SPECIFIC INSPECTION REQUIREMENTS FOR BOILER TYPES The following details are unique to specific type boilers and should be considered when performing inspections along with the general requirements as previously outlined. RB-5601 BLACK LIQUOR (KRAFT OR SULFATE) RECOVERY BOILERS WATERTUBE BOILERS Typically constructed of drums, headers and tubes, boilers of this type are used to produce steam or hot water commonly in large quantities. They range in size and pressure from small package units to extremely large field erected boilers with pressures in excess of 3000 psig (20 MPa gage). These boilers may be fired by many types of fuels such as wood, coal, gas, oil, trash and black liquor. The recovery combustion process requires a A04 reducing atmosphere near the furnace floor and an oxidizing atmosphere in the upper furnace for completion of combustion. Pressure parts within the furnace require protection from the reducing atmosphere and from sulfidation. The rate of corrosion within the furnace is temperature dependent. Boilers operating up to 900 psi (6 MPa) typically have plain carbon steel steam generating tubes with pin studs applied to the lower furnace to retain a protective layer of refractory or “frozen” smelt. Above 900 psi (6 MPa) the lower furnace tubes will typically have a special corrosion protection outer layer. The most common is a stainless steel clad “composite tube.” Other protection methods are corrosion resistant overlay welding, thermal or plasma spray coating and diffusion coating. There are many locations both internal and external where moisture and oxygen combine causing primary concern for corrosion. The fuels burned in this type of boiler may contain ash, which can form an abrasive grit in the flue gas stream. The abrasive action of the ash in high velocity flue gas can quickly erode boiler tubes. Their size and type of construction poses mechanical and thermal cyclic stresses. Unique parts associated with this type of construction such as casing, expansion supports, superheater, economizer, soot blowers, drums, headers and tubes should be inspected carefully and thoroughly in accordance with RB-5500, as applicable. The unique hazard of these boilers is the potential for an explosion if water should be combined with the molten smelt. The primary source of water is from pressure part failure, 57 NATIONAL BOARD INSPECTION CODE permitting water to enter the furnace. The owner’s inspection program is carefully developed and executed at appropriate intervals to ensure pressure part failure that could admit water to the furnace be avoided. A second source of water is the liquor fuel. Permitting black liquor of 58% or lower solids content to enter the furnace can also result in an explosion. The black liquor firing controls include devices which monitor and automatically divert the liquor from the furnace if solids content is 58% or lower. A04 In addition to the general inspection requirements for all watertube type boilers, particular awareness in the following areas is necessary: A04 • Furnace — the type and scope of wall, roof and water screen tube inspection is dependent on materials of construction, type of construction and mode of boiler operation. In all cases, furnace wall opening tubes need inspection for thinning and cracking. The typical water-cooled smelt spout can admit water to the furnace if the spout fails. Common practice is to replace these spouts in an interval shorter than that in which failure is known to occur. • Water — percentage of solids contained in the black liquor before entering the furnace should be closely monitored. Verify the black liquor firing system will automatically divert the liquor if solids drop to or below 58%. A04 • Corrosion/erosion — the potential consequences of corrosion or erosion (smeltwater explosion due to pressure-retaining part failure) requires a well planned and executed inspection program by the owner. Maintenance of boiler water quality is crucial to minimizing tube failure originating from the water side. A04 58 • Tubes — depending on type of construc- A04 tion, inspect for damage such as loss of corrosion protection, thinning, erosion, overheating, warping, elongation, bulging, blistering and misalignment. If floor tubes may have been mechanically damaged or overheated, clean the floor and perform appropriate type of inspection for suspected damage. Excursions in water treatment may result in scale and sludge on internal surfaces, creating conditions of poor heat transfer and ultimately causing crack or rupture of tube. • Welds — leaks frequently originate at A04 welds. The owner and repair agency should carefully plan and inspect all repair welds that could admit water to the furnace. Tube butt welds that could admit water to the furnace should be examined by a volumetric NDE method acceptable to the inspector. Tube leaks at attachment welds may originate from the internal stress-assisted corrosion (SAC). Minor upsets in boiler water quality and improper chemical cleaning may initiate SAC. • Emergency Response to Water Entering Fur- A04 nace — operators of Kraft recovery boilers should have a plan to immediately terminate all fuel firing and drain water from the boiler if a tube is known or suspected to be leaking into the furnace. This system may be called “Emergency Shutdown Procedure” or “ESP.” The inspector should confirm the ESP is tested and maintained such that it will function as intended and that operators will activate the system when a leak into the furnace occurs or is suspected. • Overheating — tube rupture due to over- A04 heating from low water level may admit water to the furnace. The inspector should verify a redundant low-water protection scheme is provided and maintained. PART RB — INSERVICE INSPECTION OF PRESSURE-RETAINING ITEMS – Specific procedures for inspection of black liquor recovery boilers are detailed in: A04 • A04 • A04 • – American Forest and Paper Association “Recovery Boiler Reference Manual for Owners and Operators of Kraft Recovery Boilers,” sponsored by the Operations/Maintenance Subcommittee of the Recovery Boiler Committee, Volumes I (revised June 1991), II (revised June 1991), and III (first edition October 1984.) – – The Black Liquor Recovery Boiler Advisory Committee, Recommended Practices: – Emergency Shutdown Procedure (ESP) and Procedure for Testing ESP – Safe Firing of Black Liquer Recovery Boilers – System for Black Liquor Boilers – Safe Firing of Black Liquor in Black Liquor Recovery Boilers – Safe Firing of Auxilliary Fuel in Black Liquer Recovery Boilers – Thermal Oxidation of Waste Streams in Black Liquor Recovery Boilers – Instrumentatin Checklist and Classification Guide for Instruments and Control Systems used in the Operation of Black Liquer Recovery Boilers – Recommended Guidelines for Personnel Safety 0402-21, Ultrasonic Technician Performance Test for Boiler Tube Inspection 0402-30, Inspection for Cracking of Composite Tubes in Black Liquor Recovery Boilers 0402-31, Guidelines for Evaluating the Quality of Boiler Tube Butt Welds with Ultrasonic Testing 0402-33, Guideline for Obtaining High Quality Readiographic Testing (RT) of Butt Welds in Boiler Tubes RB-5603 ORGANIC AND INORGANIC FLUID BOILERS AND VAPORIZERS These boilers are similar to standard firetube or watertube boilers with one major difference, these boilers use an inorganic or organic fluid as the heat transfer medium instead of water. The prime advantage of this boiler is that the transfer medium can carry a much larger number of BTU’s permitting greater operational efficiency. As a result, these boilers may operate at substantially higher temperatures. Because of higher operating temperatures, the possibility of steam explosion exists if the fluid medium becomes contaminated with water. There must be no water connection to this type boiler. Due to the unique design and material considerations of organic and inorganic fluid boilers and vaporizers, the following list are common areas of inspection. Technical Association of the Pulp & Paper Industry (TAPPI), Technical Information Papers: – 0402-12, Guidelines to Assure Quality Radiography of Boiler Tubes and Pipe Weldments in the Paper Industry – 0402-13, Guidelines for Specification and Inspection of Electric Resistance Welded (ERW) and Seamless Boiler Tube for Critical and Non-Critical Service – 0402-15, Installation and Repair of Pin Studs in Black Liquor Recovery Boilers; Part I: Guidelines for Accurate Tube Thickness Testing Part II: Default Layouts for Tube Thickness Surveys in Various Boiler Zones 59 • Design – specific requirements outlined in construction codes must be met, such as gage glasses shall be flat glass type with reinforced steel frames. Gage cocks shall not be used. Codes should be reviewed for specific design criteria. • Corrosion – the heat transfer medium is typically non-corrosive and, therefore, NATIONAL BOARD INSPECTION CODE corrosion occurs from moisture outside the boiler or system. Moisture may enter from an unprotected stack, washing down of equipment or leakage of sprinklers or other water lines. • Leakage – any minute signs of leakage could signify serious problems since the fluid or its vapors can be hazardous. • Thermal temperature – higher than average operational temperatures may cause metal creep which can lead to leakage. RB-5604 Extreme thermal cycling can cause cracks and leakage at joints. WASTE HEAT BOILERS Waste heat boilers are usually of firetube or watertube type and obtain their heat from an external source or process in which a portion of the BTU’s have been utilized. Generation of electrical energy is usually the primary application of waste heat boilers. The biggest disadvantage of this type of boiler is that it is not fired on the basis of load demand. Since the boiler does not have effective control over the amount of heat entering the boiler, there may be wide variations or fluctuations of metal temperatures. Waste process gasses are usually in a temperature range of 400°F (205°C) to 800°F (425°C), where combustion gasses of conventional fired boilers are at about 2000°F (1095°C). Special design considerations are made to compensate for lower combustion gas temperatures such as the use of finned high-efficiency heat absorbing tubes, and by slowing the velocity of gasses through the boiler. Erosion – typically waste heat flow is very low and erosion is not a problem, however, when waste heat is supplied from an internal combustion engine, exhaust gasses can be high enough to cause erosion. • Vibration – in some process applications and all engine waste heat applications, the boiler may be subjected to high vibration stresses. • Acid attack – in sulfuric acid processes refractory supports and steel casings are subject to acid attack. Piping, filters, heat exchangers, valves, fittings and appurtenances are subject to corrosive attacks because these parts are not normally made of corrosion resistant materials. • Dry operation – in certain applications waste heat boilers are operated without water. Care must be taken not to expose carbon steel material to temperatures in excess of 800°F (425°C) for prolonged periods. Carbides in the steel may precipitate to graphite at elevated temperatures. RB-5605 CAST-IRON BOILERS Cast-iron boilers are widely used in a variety of applications to produce low pressure steam and hot water heat. Cast-iron boilers should only be used in applications that allow for nearly 100% return of condensate or water, and are not typically used in process-type service. These boilers are designed to operate with minimum scale, mud, or sludge, which could occur if makeup water is added to this system. Due to the unique design and material considerations of waste heat boilers, the following are common areas of inspection. • • Corrosion – chemicals in waste heat gasses may create corrosive conditions and react adversely when combined with normal gasses of combustion. Water or steam leakage can create localized corrosion. Due to the unique design and material considerations of cast-iron boilers, the following are common areas of inspection. 60 PART RB — INSERVICE INSPECTION OF PRESSURE-RETAINING ITEMS • Scale and sludge – since combustion occurs at or near the bottom, accumulation of scale or sludge close to the intense heat can cause overheating and lead to cracking. • Feedwater – makeup feedwater should not come in contact with hot surfaces. Supply should be connected to a return pipe for tempering. • Section alignment – misalignment of sections can cause leakage. Leakage or corrosion between sections will not allow normal expansion and contraction which may cause cracking. • Tie rods or draw rods – used to assemble the boiler and pull the sections together. These rods must not carry any stress and need to be loose allowing for section growth during heat up. Expansion washers may be used and nuts should be just snugged allowing for expansion. • coils or induction coils. These boilers are used to service small or medium size loads and may be used in either high or low pressure steam or hot water applications. Due to the unique design and material considerations of electric boilers, the following are common areas of inspection. Push nipple or seal area – corrosion or leakage is likely at the push nipple opening usually caused by the push nipple being pushed into the seat crooked, warping due to overheating, tie rods too tight and push nipple corrosion/erosion. • Corrosion – fire sides of sections can corrode due to ambient moisture coupled with acidic flue gas deposits. • Soot – inadequate oxygen supply or improperly adjusted burner can allow for soot buildup in fireside passages. A reduction in efficiency and hot spots may occur. Soot, when mixed with water, can form acidic solutions harmful to the metal. RB-5606 • Weight stress of the elements – some electrodes and elements can be quite heavy, especially if covered with scale deposits. These elements will scale sooner and at a faster rate than internal surfaces. Excessive weight puts severe stress on the attachment fittings and welds at support points. • Thermal shock – heaters are constantly cycling on and off creating temperature gradients. • Leakage – any leakage noted at the opening where electrodes or elements are inserted is extremely dangerous due to the possible exposure of electrical wires, contacts and breakers. RB-5607 FIRED COIL WATER HEATERS These heaters are used for rapid heating of potable water or hot water service. This design utilizes a coil through which the water being heated is passed. This type of heater has very little volume and may be used in conjunction with a hot water storage vessel. Due to the unique design and material considerations of fired coil water heaters, the following are common areas of inspection. • ELECTRIC BOILERS This type boiler is heated by an electrical energy source, either by use of electric resistant 61 Erosion – size and velocity of water flow through the coil combines to create wear and thinning of the coils. If a temperature differential is created within the coil, bubbles or steam may cause grooving or cavitation. NATIONAL BOARD INSPECTION CODE • Corrosion – this type of system uses 100% makeup which contains free oxygen creating opportunities for extensive corrosion. • Vibration – operation of the burner creates a certain amount of vibration. Creation of steam, hot spots or lack of flow may create a water hammer causing extensive vibration and mechanical stresses. transfer process and causing localized overheating. Scale and sludge can also shield temperature control probes giving false readings and allowing overheating of the water. • Thermal cycling – heated water is continually replaced with cold water causing thermal stress within the vessel. • Lining – loss of lining or coating will allow for rapid deterioration of the pressure boundary. • Pressure – if water supply pressure exceeds 75% of set pressure of safety relief valve, a pressure reducing valve may be required. Fired storage water heaters are vertical pressure vessels containing water to which heat is applied. Typically gas burners are located directly beneath the storage vessel. These heaters should be insulated and fitted with an outer jacket and may be lined with porcelain, glass, galvanized metal, cement or epoxy. • Expansion – if the water heater can be isolated by such use as a check valve, it is recommended that an expansion tank be provided. Due to the unique design and material considerations of fired storage water heaters, the following are common areas of inspection. Some of the more common firetube boilers A04 are Scotch Marine, Horizontal Return (HRT), Vertical Firetube, Locomotive, and Firebox. • Corrosion – moisture may be trapped between the insulation and outer jacket which may cause corrosion of the pressure boundary. • Mud and sludge – there is 100% makeup of water allowing for accumulation of mud and sludge to build up in the bottom portions of the vessel. Any buildup can cause overheating and failure of the metal in this area. These boilers are used as heating boilers or power boilers. Due to the unique design and material considerations, firetube boilers are subject to thermal stresses due to cycling which may cause tube leakage and corrosion of joints. The following list are common areas of inspection. • Scale – due to the large volume of makeup, significant amounts of scale forming particles will adhere to the hot surfaces. RB-5608 • FIRED STORAGE WATER HEATERS RB-5609 • Scale – loose scale may accumulate in areas adjacent to the burner and lower portions of the vessel, interfering with heat 62 FIRETUBE BOILERS Waterside – scale buildup on and around the furnace tube. Scale on or around the firetubes in the first pass after the furnace (gas temperatures >1800°F [980°C]). Scale and corrosion buildup on stay rods hiding the actual diameter. Corrosion pitting on all pressure boundaries. A04 PART RB — INSERVICE INSPECTION OF PRESSURE-RETAINING ITEMS • Fireside – As previously mentioned tube to tube sheet joint leakage. Look for rust trails left by weeping joints. When in doubt where the leakage is coming from, perform a liquid penetrant exam. Take note of refractory locations protecting steel that is not water-cooled. Condensation of combustion gas dripping out of the fireside gaskets during a cold boiler start up is expected. However, if it continues after the water temperature in the boiler is at least 150°F (65°C), then further investigation to determine the source of water shall be conducted. RB-5700 sure vessel contains and the temperature and pressure at which it operates should be considered in establishing inspection criteria. Usage, materials and installation conditions should be considered in determining damage mechanisms that will affect the mechanical integrity of a pressure vessel as described in RB-4000. The general requirements for safety, pre-inspection and post-inspection activities are specified in RB-2000 and should be followed in conjunction with the specific requirements outlined in this section when performing inspections of pressure vessels. There may be occasions where more detailed procedures will be required. INSERVICE INSPECTION ACTIVITIES Any defect or deficiency in the condition, operating and maintenance practices of a boiler should be discussed with the owner or user at the time of inspection and, if necessary, recommendations made for the correction of such defect or deficiency. Follow-up inspections should be performed as needed to determine if deficiencies have been corrected satisfactorily. RB-6000 INSPECTION OF PRESSURE VESSELS RB-6010 SCOPE INSPECTIONS – GENERAL REQUIREMENTS RB-6210 CONDITION OF INSTALLATION The type of inspection given to pressure vessels should take into consideration the condition of the vessel and the environment in which it operates. This inspection may be either external or internal and use a variety of nondestructive examination methods as described in RB-3000. The inspection method may be performed when the vessel is operating on-stream or depressurized, but shall provide the necessary information that the essential sections of the vessel are of a condition to continue to operate for the expected time interval. On-stream inspection, including while under pressure, may be used to satisfy inspection requirements provided the accuracy of the method can be demonstrated. This part provides guidelines for inservice inspection of pressure vessels used to contain pressure either internal or external. This pressure may be obtained from an external source or by the application of heat from a direct or indirect source or a combination thereof. RB-6100 RB-6200 RB-6220 EXTERNAL INSPECTION The purpose of an external inspection is to provide information regarding the overall condition of the pressure vessel. The following should be reviewed: GENERAL CONDITIONS Pressure vessels are designed for a variety of service conditions. The media that a pres- 63 NATIONAL BOARD INSPECTION CODE a. Insulation or Other Coverings If it is found that external coverings such as insulation and corrosion-resistant linings are in good condition and there is no reason to suspect any unsafe condition behind them, it is not necessary to remove them for inspection of the vessel. However, it may be advisable to remove small portions of the coverings in order to investigate attachments, nozzles and material conditions. e. Miscellaneous Conditions 1. Abrasives – The surfaces of the vessel should be checked for erosion. 2. Dents – Dents in a vessel are deformations caused by their coming in contact with a blunt object in such a way that the thickness of metal is not materially impaired. Dents can create stress risers that may lead to cracking. NOTE: Precautions should be taken when removing insulation while vessel is under pressure. 3. Distortion – If any distortion is suspected or observed, the overall dimensions of the vessel shall be checked to determine the extent and seriousness of the distortion. b. Evidence of Leakage Any leakage of gas, vapor or liquid should be investigated. Leakage coming from behind insulation coverings, supports or settings or evidence of past leakage should be thoroughly investigated by removing any covering necessary until the source of leakage is established. 4. Cuts or Gouges – Cuts or gouges can cause high stress concentrations and decrease the wall thickness. Depending upon the extent of the defect, it may be necessary to repair. c. Structural Attachments The pressure vessel mountings should be checked for adequate allowance for expansion and contraction, such as provided by slotted bolt holes or unobstructed saddle mountings. Attachments of legs, saddles, skirts or other supports should be examined for distortion or cracks at welds. 5. Surface Inspection – The surfaces of shells and heads should be examined for possible cracks, blisters, bulges and other evidence of deterioration, giving particular attention to the skirt and to support attachment and knuckle regions of the heads. 6. Weld Joints – Welded joints and the adjacent heat affected zones should be examined for cracks or other defects. Magnetic particle or liquid penetrant examination is a useful means for doing this. d. Vessel Connections Manholes, reinforcing plates, nozzles or other connections should be examined for cracks, deformation or other defects. Bolts and nuts should be checked for corrosion or defects. Weep holes in reinforcing plates should remain open to provide visual evidence of leakage as well as to prevent pressure buildup between the vessel and the reinforcing plate. Accessible flange faces should be examined for distortion and to determine the condition of gasketseating surfaces. 7. Riveted Vessels – On riveted vessels, examine rivet head, butt strap, plate and caulked edge conditions. If rivet shank corrosion is suspected, hammer testing for soundness or spot radiography at an angle to the shank axis may be useful. 64 PART RB — INSERVICE INSPECTION OF PRESSURE-RETAINING ITEMS RB-6230 If a preliminary inspection reveals unsafe conditions such as loose or corroded internals or badly corroded internal ladders or platforms, steps should be taken to remove or repair such parts so that a detailed inspection may be made. INTERNAL INSPECTION A general visual inspection in vessels is the first step in making an internal inspection of pressure vessels that are susceptible to corrosion. Vessels should be inspected for the conditions identified in RB-4000. d. Corrosion The type of corrosion (local pitting or uniform), its location and any obvious data should be established. Data collected for vessels in similar service will aid in locating and analyzing corrosion in the vessel being inspected. The liquid level lines, the bottom and the shell area adjacent to and opposite inlet nozzles are often locations of most severe corrosion. Welded seams and nozzles and areas adjacent to welds are often subjected to accelerated corrosion. The following should be reviewed: a. Vessel Connections Threaded connections should be inspected to ensure that an adequate number of threads are engaged. All openings leading to any external fittings or controls should be examined as thoroughly as possible to ensure they are free from obstructions. b. Vessel Closures Any special closures including those on autoclaves, normally termed quick actuating (quick opening) closures (RB-6460) which are used frequently in the operation of a pressure vessel, should be checked by the Inspector for adequacy and wear. A check should also be made for cracks at areas of high stress concentration. Door safety interlock mechanisms, “man inside” alarm and associated audible and visual alarms should be verified. The man inside alarm is a safety cable running the length of the internal workspace that can be pulled by the operator, thereby shutting down all autoclave functions and initiating audible and visual alarms. RB-6240 INSPECTION OF PARTS AND APPURTENANCES Parts and appurtenances to be inspected depend upon the type of vessel and its operating conditions. The Inspector should be familiar with the operating conditions of the vessel and with the causes and characteristics of potential defects and deterioration. c. Vessel Internals Where pressure vessels are equipped with removable internals, these internals need not be completely removed provided assurance exists that deterioration in regions rendered inaccessible by the internals is not occurring to an extent that might constitute a hazard or to an extent beyond that found in more readily accessible parts of the vessel. RB-6250 GAGES, SAFETY DEVICES, AND CONTROLS RB-6251 GAGES The pressure indicated by the required gage should be compared with other gages on the same system. If the pressure gage is not mounted on the vessel itself, it shall be installed in such a manner that it correctly indicates the actual pressure in the vessel. When required, the accuracy of pressure gages should be verified by comparing the 65 NATIONAL BOARD INSPECTION CODE readings with a standard test gage or a dead weight tester. a. An ASME Manufacturer’s Data Report or, if the vessel is not ASME Code stamped, other equivalent specifications. The location of a pressure gage should be observed to determine whether it is exposed to high temperature from an external source or to internal heat due to lack of protection by a proper siphon or trap. Provisions should be made for blowing out the pipe leading to the steam gage RB-6252 b. Form NB-5 Boiler or Pressure Vessel Data Report - First Internal Inspection, may be used for this purpose. It shall show the following identification numbers as applicable. National Board No. Jurisdiction No. Manufacturer Serial No. Owner-User No. SAFETY DEVICES See RB-8000 for the inspection of safety devices (pressure relief valves and non-closing devices such as rupture disks) used to prevent the overpressure of pressure vessels. RB-6253 c. Complete pressure-relieving device information including safety or safety relief valve spring data or rupture disk data and date of latest inspection. d. Progressive record including, but not limited to, the following: CONTROLS/DEVICES Any control device attached to a vessel should be demonstrated by operation or the Inspector should review the procedures and records for verification of proper operation. 1. Location and thickness of monitor samples and other critical inspection locations. Temperature measuring devices shall be checked for accuracy and general condition. RB-6300 2. Limiting metal temperature and location on the vessel when this is a factor in establishing the minimum allowable thickness. RECORDS REVIEW (Reference RB-2000) 3. Computed required metal thicknesses and maximum allowable working pressure for the design temperature and pressure relieving device opening pressure, static head and other loadings. The Inspector shall review any pressure vessel log, record of maintenance, corrosion rate record or any other examination results. The Inspector should consult with the owner or user regarding repairs or alterations made, if any, since the last internal inspection. The Inspector shall review the records of such repairs or alterations for compliance with applicable requirements. 4. Test pressure if tested at the time of inspection. 5. Scheduled (approximate) date of next inspection. A permanent record shall be maintained for each pressure vessel. This record should include the following: 6. Date of installation and date of any 66 PART RB — INSERVICE INSPECTION OF PRESSURE-RETAINING ITEMS significant change in service conditions (pressure, temperature, character of contents or rate of corrosion). or cracking. Inspect with special attention all exposed internal welds at or below the normal water line. 7. Drawings showing sufficient details to permit calculation of the service rating of all components on pressure vessels used in process operations subject to corrosive conditions. Detailed data with sketches where necessary may serve this purpose when drawings are not available. b. Shell – Inspect exterior surfaces for corrosion or leaks. Inspect interior for pitting, corrosion, erosion, thinning, wastage of metal, cracks, etc. RB-6400 RB-6410 c. Spray Nozzles and Trays – Inspect all nozzles and spray areas for erosion, wear, wastage and broken parts or supports. Check to see that nozzles are not plugged and that all lines to nozzles are open. Inspect all trays for holes, erosion, wastage, broken or defective brackets, and broken support attachments. INSPECTIONS FOR SPECIFIC TYPES OF PRESSURE VESSELS d. Condenser and Vents – Examine all vent lines to see that they are open to assure proper exiting of the gases. Inspect the condenser unit to verify it is operable and not plugged with scale or sludge. Check for corrosion, pitting, erosion and broken parts. GENERAL Inspection and examination requirements identified below should also include the additional requirements mentioned above. RB-6420 e. Supports – Inspect all support structures for mechanical damage, cracks, loose bolting and bent or warped components. Check all welds, especially attaching supports to the pressure boundary. DEAERATORS The deaerator is used to remove undesirable gases in the system and is exposed to the following: harmful gases, fluctuation in temperature and pressure, erosion and vibration. The air and water atmosphere in the deaerator has a corrosive effect and may contain high concentrations of hydrogen ions, which can cause hydrogen cracking, hydrogen embrittlement or corrosion fatigue. The water entering the deaerator sometimes carries acids or oil which can cause acidic attacks on the metal. RB-6430 COMPRESSED AIR VESSELS Compressed air vessels include receivers, separators, filters and coolers. Considerations to be concerned include temperature variances, pressure limitations, vibration and condensation. Drain connections should be verified to be free of any foreign material that may cause plugging. Inspection shall consist of the following: a. Welds – Inspect all longitudinal and circumferential welds, including the Heat Affected Zone (HAZ), visually along their entire length. Examine nozzle and attachment welds for erosion, corrosion Inspection shall consist of the following: a. Welds – Inspect all welds for cracking or gouging, corrosion and erosion. Particular 67 NATIONAL BOARD INSPECTION CODE attention should be given to the welds that attach brackets supporting the compressor. These welds may fail due to vibration. inspect the bolts for wear and stretch. Any safety interlocks associated with the closure shall be checked for function and proper working order. b. Shells/Heads – Externally, inspect the base material for environmental deterioration and impacts from objects. Hot spots and bulges are signs of overheating and should be noted and evaluated for acceptability. Particular attention should be paid to the lower half of the vessel for corrosion and leakage. For vessels with manways or inspection openings, an internal inspection shall be performed for corrosion, erosion, pitting, excessive dirt buildup and leakage around inspection openings. UT thickness testing may be used where internal inspection access is limited or to determine actual thickness when corrosion is suspected. RB-6440 EXPANSION TANKS The purpose of an expansion tank is to provide an air cushion to a system that will allow for expansion and contraction due to temperature, thus minimizing fluctuations in pressure due to temperature variances. These vessels are susceptible to corrosion due to the air and water interface. Inspection shall consist of the following; a. Design/Operation – Verify from the nameplate the Code of construction, temperature and pressure ratings to assure jurisdictional and system compatibility. It is common to find expansion tanks water logged due to leakage of air out of the tank, therefore it is important to verify the water level either by sight glass or sounding the tank. c. Fittings and Attachments – Inspect all fittings and attachments for alignment, support, deterioration, damage and leakage around threaded joints. Any internal attachments such as supports, brackets, or rings shall be visually examined for wear, corrosion, erosion and cracks. b. Surface Conditions – Check all surfaces external and internal, if possible, for any leaks, corrosion, erosion, cracks and dents that may lead to failure. Thickness checks may be applicable to determine wastage of base material. d. Operation – Check the nameplate to determine the allowed working pressure and temperature of the vessel. Assure the set pressure of the safety valve does not exceed that allowed on the nameplate and determine that the capacity of the safety valve is greater than the capacity of the compressor. Ensure there is a functioning manual or automatic condensate drain. c. Supports and Attachments – These vessels are usually suspended from the ceiling by hangers or straps causing concentration of stresses in these areas. Specifically inspect for corrosion, wear and cracks in these areas. If the vessel is fitted with a water sight glass, inspect for visual cleanliness, water leakage and gasket tightness. e. Quick-Closure Attachments – Filter-type vessels usually have one quick type closure head for making filter changes. Carefully examine the seating surfaces for wear, erosion and corrosion. Visually 68 PART RB — INSERVICE INSPECTION OF PRESSURE-RETAINING ITEMS RB-6450 c. All interior welds and highly stressed areas should be examined by the wet fluorescent magnetic particle-testing method (WFMT) using an A/C yoke for magnetization. Note that weld cracks are often transverse in orientation. It is extremely important to ensure that the NDE method used will disclose cracks in any orientation. LIQUID AMMONIA VESSELS Special attention should be placed on these vessels because the media is corrosive. It is known that vessels in liquid ammonia service are susceptible to stress corrosion cracking (SCC) in areas of high stress. High strength and coarse-grained materials seem to be more at risk of SCC than are fine-grained or more moderate strength materials, although no commonly used steels appear to be immune to the problem. Postweld heat treatment of new or weld-repaired vessels or cold formed heads is beneficial in reducing the incidence of SCC. The presence of 0.2% minimum water in the liquid ammonia also inhibits SCC. Any leak should be thoroughly investigated and the necessary corrective action initiated. d. If cracks are discovered, a calculation must be made to determine what depth of grinding may be carried out for crack removal (without encroaching on the minimum thickness required by the construction standard or equivalent). e. Where possible, crack removal by grinding is the preferred method of repair. Since the stresses at the crack tips are quite high, even very fine cracking should be eliminated. Inspection of Parts and Appurtenances Where existing openings permit, perform a visual internal inspection of the vessel. Look for any obvious cracks (very advanced SCC) and note areas which are subject to high stress such as welds, welded repairs, head-to-shell transitions, sharp interior corners and interior surfaces opposite external attachments or supports. It is not intended that the vessel provide for access. It is understood that internal inspections will be made if there is access to the internal surfaces. f. Where crack depth is such that removal requires weld repair, a weld procedure should be employed that will minimize HAZ hardening and residual stresses. Whenever possible, weld repairs — regardless of their size — should be postweld heat treated. g. Re-inspect by WFMT to ensure complete crack removal. a. If valves or fittings are in place, check to ensure that these are complete and functional. Parts made of copper, zinc, silver or alloys of these metals are unsuitable for ammonia service and should be replaced with parts of steel or other suitable materials. h. It is not intended to inhibit or limit the use of other evaluation methods. It is recognized that acoustic emission and fracture mechanics are acceptable techniques for assessing structural integrity of vessels. Analysis by fracture mechanics may be used to assess the structural integrity of vessels when complete removal of all ammonia stress cracks is not practical. If alternative methods are used, the above recommendation that all cracks be removed, even fine cracks may not apply. b. Fittings should be removed or otherwise protected from power buffing or light sandblasting when preparing the interior surface of the vessels for inspection. 69 NATIONAL BOARD INSPECTION CODE c. Gages and Pressure Relieving Devices The Inspector should note the pressure indicated by the gage and compare it with other gages on the same system. If the pressure gage is not mounted on the vessel itself, it should be ascertained that the gage is on the system and installed in such a manner that it correctly indicates actual pressure in the vessel. ing maintenance and operation, as a guide in forming an opinion of the care the equipment receives. The history of the vessel should be established, including: year built, materials of construction, extent of postweld heat treatment, previous inspection results and repairs or alterations performed. Any leak should be thoroughly investigated and the necessary corrective action initiated. See RB-8000 for the inspection of safety devices (pressure relief valves) used to prevent the overpressure of liquid ammonia vessels. Pressure-relief devices in ammonia service cannot be tested in place using system pressure. Bench testing is required. RB-6460 Inspection of Parts and Appurtenances a. Seating surfaces of the closure device, including but not limited to the gaskets, O-rings or any mechanical appurtenance to ensure proper alignment of the closure to the seating surface, should be inspected. This inspection can be made by using powdered chalk or any substance that will indicate that the closure is properly striking the seating surface of the vessel flange. If this method is used, a check should be made to ensure that: INSPECTION OF PRESSURE VESSELS WITH QUICKACTUATING CLOSURES This part describes guidelines for inspection of pressure vessels equipped with quick-actuating closures. Due to the many different designs of quick-actuating closures, potential failures of components that are not specifically covered should be considered. The scope of inspection should include areas affected by abuse or lack of maintenance and a check for inoperable or bypassed safety and warning devices. 1. Material used will not contaminate the gasket or material with which it comes into contact. 2. The substance used should be completely removed after the examination. b. The closure mechanism of the device should be inspected for freedom of movement and proper contact with the locking elements. This inspection should indicate that the movable portions of the locking mechanism are striking the locking element in such a manner that full stroke can be obtained. Inspection should be made to ensure that the seating surface of the locking mechanism is free of metal burrs and deep scars, which would indicate misalignment or improper operation. A check should be made for proper alignment of the door hinge mechanisms to ensure that adjustment screws and locking nuts are Temperatures above that for which the quickactuating closure was designed can have an adverse effect on the safe operation of the device. If parts are found damaged and excessive temperatures are suspected as the cause, the operating temperatures may have exceeded those temperatures recommended by the manufacturer. Rapid fluctuations in temperatures due to rapid start-up and shutdown may lead to cracks or yielding caused by excessive warping and high thermal stress. A careful observation should be made of the condition of the complete installation, includ- 70 PART RB — INSERVICE INSPECTION OF PRESSURE-RETAINING ITEMS properly secured. When deficiencies are noted, the following corrective actions should be initiated: the operator can accurately determine the pressure in the vessel while it is in operation. The gage dial size should be of such a diameter that it can be easily read by the operator. This gage should have a pressure range of at least 1-1/2 times, but not more than four times, the operating pressure of the vessel. There should be no intervening valve between the vessel and gage. 1. If any deterioration of the gasket, O-ring, etc., is found, the gasket, O-ring, etc., should be replaced immediately. Replacements should be in accordance with the vessel manufacturer’s specifications. b. The pressure gage should be of a type that will give accurate readings, especially when there is a rapid change in pressure. It should be of rugged construction and capable of withstanding severe service conditions. Where necessary, the gage should be protected by a siphon or trap. 2. If any cracking or excessive wear is discovered on the closing mechanism, the owner or user should contact the original manufacturer of the device for spare parts or repair information. If this cannot be accomplished, the owner or user should contact an organization competent in quick-actuating closure design and construction prior to implementing any repairs. c. Pressure gages intended to measure the operating pressure in the vessel are not usually sensitive or easily read at low pressures approaching atmospheric. It may be advisable to install an auxiliary gage which reads inches of water (mm of mercury) and is intended to measure pressure from atmospheric through low pressures. This gives assurance that there is zero pressure in the vessel before opening. It would be necessary to protect the auxiliary low pressure gage from the higher operating pressures. 3. Defective safety or warning devices should be repaired or replaced prior to further operation of the vessel. 4. Deflections, wear or warping of the sealing surfaces may cause out-ofroundness and misalignment. The manufacturer of the closure should be contacted for acceptable tolerances for out-of-roundness and deflection. d. Provisions should be made to calibrate pressure gages or to have them checked against a master gage as frequently as necessary. The operation of the closure device through its normal operating cycle should be observed while under control of the operator. This should indicate if the operator is following posted procedures and if the operating procedures for the vessel are adequate. e. A check should be made to ensure that the closure and its holding elements must be fully engaged in their intended operating position before pressure can be applied to the vessel. A device should be provided that prevents the opening mechanism from operating unless the vessel is completely depressurized. Gages, Safety Devices, and Controls a. The required pressure gage should be installed so that it is visible from the operating area located in such a way that 71 NATIONAL BOARD INSPECTION CODE f. Quick-actuating closures held in position by manually operated locking devices or mechanisms and which are subject to leakage of the vessel contents prior to disengagement of the locking elements and release of the closure, shall be provided with an audible and/or visible warning device to warn the operator if pressure is applied to the vessel before the closure and its holding elements are fully engaged and to warn the operator if an attempt is made to operate the locking device before the pressure within the vessel is released. Pressure tending to force the closure clear of the vessel must be released before the closure can be opened for access. particle, liquid penetrant, ultrasonic, radiography, eddy current, visual, metallographic examination and acoustic emission. When there is doubt as to the extent of a defect or detrimental condition found in a pressure vessel, the Inspector may require additional NDE. RB-6600 REMAINING LIFE AND INSPECTION INTERVALS See Appendix 8 for inspection requirements. New pressure vessels are placed in service to operate under their design conditions for a period of time determined by the service conditions and the corrosion rate. If the pressure vessel is to remain in operation, the allowable conditions of service and the length of time before the next inspection shall be based on the conditions of the vessel as determined by the inspection. See RB-9000 for determining remaining life and inspection intervals. RB-6480 RB-6700 RB-6470 GRAPHITE PRESSURE EQUIPMENT FIBER REINFORCED VESSELS See Appendix 9 for inspection requirements. RB-6490 Any defect or deficiency in the condition, operating and maintenance practices of the pressure vessel should be discussed with the owner or user at the time of inspection and, if necessary, recommendations made for the correction of such defect or deficiency. Follow-up inspections should be performed as needed to determine if deficiencies have been corrected satisfactorily. PROPANE LP GAS VESSELS See Appendix H for inspection requirements. RB-6500 INSERVICE INSPECTION ACTIVITIES NONDESTRUCTIVE EXAMINATION (NDE) NDE may be employed to assess the condition of the pressure vessel as described in RB-3000. These examination methods should be performed by experienced and qualified individuals using procedures acceptable to the Jurisdiction. Generally, some form of surface preparation will be required prior to the use of these examination methods: magnetic RB-7000 INSPECTION OF PIPING SYSTEMS RB-7010 SCOPE This section provides guidlines for internal and external inspection of piping and piping systems. 72 PART RB — INSERVICE INSPECTION OF PRESSURE-RETAINING ITEMS RB-7100 GENERAL CONDITIONS Piping systems are designed for a variety of service conditions. The media that a piping system contains, the temperature at which it operates and the piping corrosion history should be considered in establishing piping inspection criteria. Particular attention should be given to piping systems that are subject to corrosion, high temperatures and hazardous fluid or gasses. Piping operating beyond design temperature limits can cause sufficient deterioration of piping material properties due to graphitization, embrittlement and creep to render the piping system unfit for continued service (RB-4000). INSPECTION RB-7310 EXTERNAL INSPECTION OF PIPING Piping should be externally inspected for the following: a. Evidence of leakage. (RB-7330) b. Provision for expansion and adequate support. (RB-7340) c. Proper alignment of piping joints and bolted connections. Check for missing bolts or studs, nuts and improper or inadequate bolted connection thread engagement. Also check visible gasket and gasket alignment condition. Threaded connections should also be inspected for inadequate or excessive thread engagement. Any externally or internally corroded piping should be evaluated for integrity and repaired or replaced as necessary. Requirements specified for inspection activities and safety are identified in RB-2000 and should be reviewed and followed as applicable. RB-7200 RB-7300 d. Past or present evidence of excessive vibration or cyclic activity such as loose or missing piping supports or piping insulation. If such activity is present, piping and piping joints should be inspected for potential fatigue cracking. ASSESSMENT OF PIPING DESIGN All pipe material and fittings should be properly rated for the maximum service conditions to which they are subjected under normal operating conditions. The design corrosion allowance of the piping system should be considered when reviewing the current piping thickness data. e. Evidence of general corrosion, excessive external pitting, corrosion scale buildup, exfoliation, erosion, cuts, dents, distortion or other detrimental conditions such as pipe sweating, water hammer damage or hot spots. Ultrasonic thickness measurements should be taken in suspect areas to ensure adequate remaining piping wall thickness. If a piping system has a previous history of ultrasonic wall thickness measurements, the Inspector should review this data and request additional wall thickness measurements if warranted. f. Evidence of corrosion under piping insulation (CUI) or other weather related damage to piping coatings. g. Evidence of freeze damage such as bulging, striations or surface fissures. 73 NATIONAL BOARD INSPECTION CODE h. Dead leg or stagnant piping internal corrosion issues. Ultrasonic thickness measurements should be taken in suspect locations. Radiography is also useful to assess internal deposits and subsequent corrosion in no flow piping locations. RB-7320 not less than 70°F (20°C) and the maximum temperature during inspection should not exceed 120°F (50°C). The potential corrosive effect of the test fluid on the piping material should be considered. RB-7340 INTERNAL INSPECTION OF PIPING Visual inspection should include a check for evidence of improper piping support or support design. Piping supports should not be bottomed out or fully extended. Piping supports should keep piping in alignment and prevent piping from colliding with other piping or stationary objects. The alignment of connections between anchored equipment should be observed to determine if any change in position of the equipment due to settling, excessive cyclic activity, steady state stresses beyond design allowances or other causes has placed an undue strain on the piping or its connections. Inadequate support or the lack of provision for expansion may cause broken attachment welds, cracks or leakage at fittings. Missing, damaged or loose insulation materials may be an indication of vibration or pipe movements resulting from improper support. Where the internal surfaces of piping, valves and gasket surfaces are accessible to visual examination, internal inspection should include an examination of all available surfaces. Nondestructive examination for internal corrosion may be used to supplement the inspection. Boroscope or camera inspections are also useful to augment piping internal inspections. a. Internal pipe surfaces should be cleaned before inspection, if necessary. b. The internal surfaces of piping, piping welds and connections, fittings, valves and gasket surfaces should be inspected for localized corrosion, pitting, erosion, blistering, cracking and impingement damage. RB-7330 PROVISIONS FOR EXPANSION AND SUPPORT Piping support locations should be closely inspected at the support points for external and crevice corrosion concerns. EVIDENCE OF LEAKAGE A leak should be thoroughly investigated and corrective action initiated. Leaks beneath piping insulation should be approached with caution, especially when removing insulation from a pressurized piping system for inspection. A pressure test may be required to obtain additional information regarding the extent of a defect or detrimental condition. RB-7350 GAGES, SAFETY DEVICES, CONTROLS RB-7351 GAGES Piping system pressure gages should be removed for testing unless there is other information to assess their accuracy. Faulty pressure gages should be recalibrated or replaced as necessary. To determine tightness, the test pressure need be no greater than the normal operating pressure. The metal temperature should be 74 PART RB — INSERVICE INSPECTION OF PRESSURE-RETAINING ITEMS RB-7352 These devices are not designed or intended to control the pressure in the system during normal operation. Instead, they are intended to function when normal operating controls fail or abnormal system conditions are encountered. SAFETY DEVICES See RB-8000 for information on the inspection of pressure-relieving devices used to prevent the over pressure of piping systems. RB-7353 Periodic inspection and maintenance of these important safety devices is critical to ensure their continued functioning and to provide assurance that they will be available when called upon to operate. CONTROLS Piping connections utilizing a quick-disconnect coupling should be checked to ensure that the coupling and its holding elements are fully engaged in their intended operating position. Means should be provided that warn the operator against disengaging the coupling or prevent the opening mechanism from operating unless the piping is completely depressurized. RB-7400 Inspection areas of concern include: a. safety considerations b. device data c. condition of the device d. condition of the installation e. testing and operational inspection. INSERVICE INSPECTION ACTIVITIES RB-8100 Any defect or deficiency in the condition, operating and maintenance practices of a piping system should be discussed with the owner or user at the time of inspection and, if necessary, recommendations made for the correction of such defect or deficiency. Follow-up inspections should be performed as needed to determine if deficiencies have been corrected satisfactorily. RB-8000 INSPECTION OF PRESSURE RELIEF DEVICES RB-8010 SCOPE SAFETY CONSIDERATIONS Inspectors are cautioned that the operation of these safety devices involve the discharge of high pressure and/or high temperature fluids. Extreme caution should be used when working around these devices due to hazards to personnel. Suitable hearing protection should be provided during testing because extremely high noise levels, which may be encountered, can damage hearing. RB-8200 DEVICE DATA Nameplate marking or stamping of the device should be compared to stamping on the protected pressure-retaining item. For a single device, the set pressure shall be no higher than the maximum allowable working pressure (MAWP) marked on the protected pressureretaining item or system. The most important appurtenances on any pressurized system are the pressure relief devices provided for overpressure protection of that system. These are devices such as safety valves, safety relief valves pilot valves, and rupture disks or other non-reclosing devices which are called upon to operate and reduce an overpressure condition. If multiple devices are provided, the difference between set pressures shall not exceed that permitted by the original code of 75 NATIONAL BOARD INSPECTION CODE construction. The set pressure of additional devices may exceed the MAWP, as permitted by the original code of construction. RB-8300 Inspect inlet piping and ensure it meets the requirements of the original code of construction. For pressure relief valves, check that the inlet pipe size is not smaller than the device inlet size. Verify nameplate capacity and, if possible, compare to system capacity requirements. Check identification on seals and ensure they match nameplates or other identification (repair or reset nameplate) on the valve or device. RB-8210 INSTALLATION CONDITION Inspect discharge piping and ensure it meets the original code of construction. Check that the discharge pipe size is not smaller than the device outlet size. Check that the valve drain piping is open. DEVICE CONDITION Check for evidence that the valve or device is leaking or not sealing properly. Check drainage of discharge piping. Check that inlet and discharge piping are not binding or placing excessive stress on the valve body which can lead to distortion of the valve body and leakage or malfunction. Seals for adjustments should be intact and show no evidence of tampering. Connecting bolting should be tight and all bolts intact. Check the condition and adequacy of piping supports. Discharge piping should be supported independent of the device itself. The valve should be examined for deposits or material buildup. Check for possible hazards to personnel from the valve discharge or discharge pipe. Evidence of rust or corrosion should be checked. Check that there are no intervening isolation valves between the pressure source and the valve inlet or between the valve outlet and its point of discharge. (Isolation valves may be permitted in some pressure vessel service. See RB-8520 and jurisdictional requirements. Isolation valves are not permitted for power boilers, heating boilers or water heaters). Check for damaged or misapplied parts. If a drain hole is visible, ensure it is not clogged with debris or deposits. Check for test gags left in place after pressure testing of the unit. Bellows valves shall be checked to ensure the bonnet vent is open or piped to a safe location. The vent shall not be plugged since this will cause the valve set pressure to be high if the bellows develops a leak. Leakage noted from the vent indicates the bellows is damaged and will no longer protect the valve from the effects of back pressure. A change-over valve which is used to install two pressure relief devices on a single vessel location, for the purpose of switching from one device to a spare device, is not considered a block valve if it is arranged such that there is no intermediate position which will isolate both pressure relief devices from the protected system. Change-over valves should be carefully evaluated to ensure they do not have excessive pressure drop which could affect the pressure relief device operation or capacity. 76 PART RB — INSERVICE INSPECTION OF PRESSURE-RETAINING ITEMS These devices are commonly used in pressure vessel service. They may also be used in some boiler applications. It is recommended that the jurisdiction be contacted to determine their acceptability on boiler applications. RB-8400 fluids which are not easily removed or neutralized. If a test cannot be safely performed, the valve shall be disassembled, cleaned and decontaminated, repaired, and reset. If a valve has been removed for testing, the inlet and outlet connections should be checked for blockage by product buildup or corrosion. TESTING AND OPERATIONAL INSPECTION Pressure relief valves must be periodically tested to ensure that they are free to operate and will operate in accordance with the requirements of the original code of construction. Testing should include device set or opening pressure, reclosing pressure where applicable, and seat leakage evaluation. Tolerances specified for these operating requirements in the original code of construction shall be used to determine the acceptability of test results. Valves may be tested using lift assist devices when testing at full pressure may cause damage to the valve being tested or it is impractical to test at full pressure due to system design considerations. Lift assist devices apply an auxiliary load to the valve spindle or stem, and using the measured inlet pressure, applied load and other valve data allow the set pressure to be calculated. If a lift assist device is used to determine valve set pressure, the conditions of RA-2283 shall be met. It should be noted that false set pressure readings may be obtained for valves which are leaking excessively or otherwise damaged. Testing may be accomplished by the owner on the unit where the valve is installed or at a qualified test facility. In many cases, testing on the unit may be impractical, especially if the service fluid is hazardous or toxic. Testing on the unit may involve the bypassing of operating controls and should only be performed by qualified individuals under carefully controlled conditions. It is recommended that a written procedure be available to conduct this testing. If valves are not tested on the system using the system fluid, the following test mediums shall be used: a. High pressure boiler safety valves, high temperature hot water boiler safety relief valves, low pressure steam heating boilers: steam; a. The Inspector should assure that calibrated equipment has been used to perform this test and the results should be documented by the owner. b. Hot water heating boiler safety relief valves: steam, air, or water; c. Hot water heater temperature and pressure relief valves: air or water; b. If the testing was performed at a test facility, the record of this test should be reviewed to ensure the valve meets the requirements of the original code of construction. Valves which have been in toxic, flammable or other hazardous services shall be carefully decontaminated before being tested. In particular, the closed bonnet of valves in these services may contain d. Air and gas service process safety relief valves: air, nitrogen or other suitable gas; e. Liquid service process pressure relief valves: water or other suitable fluid; 77 NATIONAL BOARD INSPECTION CODE f. Process steam service safety relief valves: steam or air with manufacturer’s steam to air correction factor. sible organization and a tag identifying the organization and the date of the adjustment shall be installed. NOTE: Valves being tested after a repair must be tested on steam except as permitted by RA-2282. If a major adjustment is needed, this may indicate the valve is in need of repair or has damaged or misapplied parts. Its condition should be investigated accordingly. As an alternative to a pressure test, the valve may be checked by the owner for freedom of operation by activating the test or “try” lever (manual check). For high pressure boiler and process valves this test should be performed only at a pressure greater than 75% of the stamped set pressure of the valve or the lifting device may be damaged. This test will only indicate that the valve is free to operate and does not provide any information on the actual set pressure. All manual checks should be performed with some pressure under the valve in order to flush out debris from the seat which could cause leakage. Systems with multiple valves will require the lower set valves to be held closed to permit the higher set valves to be tested. A test clamp or “gag” should be used for this purpose. The spring compression screw shall not be tightened. It is recommended that the test clamps be applied in accordance with the valve manufacturer’s instructions when the valve is at or near the test temperature and be applied hand tight only to avoid damage to the valve stem or spindle. Upon completion of set pressure testing, all pressure relief valves gags shall be removed. NOTE: The manual check at 75% or higher is based on lift lever design requirements for ASME Section I and VIII valves. Code design requirements for lifting levers for Section IV valves require that the valve be capable of being lifted without pressure. RB-8410 RECOMMENDED INSPECTION AND TEST FREQUENCIES If a valve is found to be stuck closed, the system should immediately be taken out of service until the condition can be corrected, unless special provisions have been made to operate on a temporary basis (such as additional relief capacity provided by another valve). Power Boilers If a pressure test indicates the valve does not open within the requirements of the original code of construction, but otherwise is in acceptable condition, minor adjustments (defined as no more than twice the permitted set pressure tolerance) shall be made by an organization that meets the requirements of RA-2200 to reset the valve to the correct opening pressure. All adjustments shall be resealed with a seal identifying the respon- b. Pressure greater than 400 psig (3 MPa): Pressure test to verify nameplate set pressure every three years or as determined by operating experience as verified by testing history. a. Pressure less than 400 psig (3 MPa): Manual check every 6 months; pressure test annually to verify nameplate set pressure or as determined by operating experience as verified by testing history. Pressure tests should be performed prior to bringing the boiler down for planned internal inspection so needed repairs or adjustments can be made while the boiler is down. 78 PART RB — INSERVICE INSPECTION OF PRESSURE-RETAINING ITEMS found to be defective or damaged by system contents during inspection, intervals should be shortened until acceptable inspection results are obtained. Where test records and/or inspection history are not available, the following inspection and test frequencies are suggested. High Temperature Hot Water Boilers Pressure test annually to verify nameplate set pressure or as determined by operating experience as verified by testing history. For safety reasons, removal and testing on a steam test bench is recommended. Such testing will avoid damaging the safety valve by discharge of a steam water mixture, which could occur if the valve is tested in place. Service Low Pressure Steam Heating Boilers Manual check quarterly; pressure test annually prior to steam heating season to verify nameplate set pressure. Inspection Frequency Steam .......................................Annual Air & Clean .............................Every three years Dry Gasses Pressure relief valves.............Every five years in combination with rupture disks Hot Water Heating Boilers Manual check quarterly; pressure test annually prior to steam heating season to verify nameplate set pressure. Propane, Refrigerant .............Every five years All others ................................Per inspection history NOTE: The frequencies specified for the testing of pressure relief valves on boilers is primarily based on differences between high pressure boilers which are continuously manned and lower pressure automatically controlled boilers that are not monitored by a boiler operator at all times. When any boiler experiences an over-pressure condition such that the safety or safety relief valves actuate, the valves should be inspected for seat leakage and other damage as soon as possible and any deficiencies corrected. Establishment of Inspection and Test Intervals Where a recommended test frequency is not listed, the valve user and Inspector must determine and agree on a suitable interval for inspection and test. Some items to be considered in making this determination are: a. Jurisdictional requirements; b. Records of test data and inspections from similar processes and similar devices in operation at that facility; Water Heaters Manual check every two months. Due to the relatively low cost of safety valves for this service, it is recommended that a defective valve be replaced with a new valve if a repair or resetting is indicated. c. Recommendations from the device manufacturer. In particular, when the valve includes a non-metallic part such as a diaphragm, periodic replacement of those parts may be specified; Pressure Vessels and Piping Frequency of test and inspection of pressure relief devices for pressure vessel and piping service is greatly dependent on the nature of the contents and operation of the system and only general recommendations can be given. Inspection frequency should be based on previous inspection history. If valves are d. Operating history of the system. Systems with frequent upsets where a valve has actuated require more frequent inspection; 79 NATIONAL BOARD INSPECTION CODE e. Results of visual inspection of the device and installation conditions. Signs of valve leakage, corrosion or damaged parts all indicate more frequent operational inspections; f. immediately by repair or replacement of the device. Many users will maintain spare pressure relief devices so the process or system is not affected by excessive downtime. Pressure relief valves are mechanical devices which require periodic preventive maintenance even though external inspection and test results indicate acceptable performance. There may be wear on internal parts, galling between sliding surfaces or internal corrosion and fouling which will not be evident from an external inspection or test. Periodic re-establishment of seating surfaces and the replacement of soft goods such as o-rings and diaphragms are also well advised preventative maintenance activities which can prevent future problems. If the valve is serviced, a complete disassembly, internal inspection and repair as necessary, such that the valves condition and performance are restored to a like new condition, should be done by an organization meeting the requirements of RA-2200. Installation of a valve in a system with a common discharge header. Valves discharging into a common collection pipe may be affected by the discharge of other valves by the corrosion of parts in the outlet portion of the valve or the buildup of products discharged from those valves; g. Ability to coordinate with planned system shutdowns. The shutdown of a system for other maintenance or inspection activities is an ideal time for the operational inspection and test of a pressure relief valve; h. Critical nature of the system. Systems which are critical to plant operation or where the effects of the discharge of fluids from the system are particularly detrimental due to fire hazard, environmental damage or toxicity concerns all call for more frequent inspection intervals to ensure devices are operating properly; i. Service records with test results and findings should be maintained for all over pressure protection devices. A service interval of no more than three inspection intervals or ten years, whichever is less, is recommended to maintain device condition. Results of the internal inspection and maintenance findings can then be used to establish future service intervals. Where the effects of corrosion, blockage by system fluid or ability of the valve to operate under given service conditions are unknown (such as in a new process or installation), a relatively short inspection interval, not to exceed one year or the first planned shutdown, whichever is shorter, shall be established. At that time the device shall be visually inspected and tested. If unacceptable test results are obtained the inspection interval shall be reduced by 50% until suitable results are obtained. RB-8500 ADDITIONAL INSPECTION INFORMATION The following additional items should be considered for the specified services. Establishment of Service Intervals The above intervals are guidelines for periodic inspection and testing. Typically if there are no adverse findings a pressure relief valve would be placed back in service until the next inspection. Any unacceptable conditions that are found by the inspection shall be corrected RB-8510 BOILERS If boilers are piped together with maximum allowable working pressures differing by more than six percent, additional protective devices may be required on the lower pressure 80 PART RB — INSERVICE INSPECTION OF PRESSURE-RETAINING ITEMS units to protect them from overpressure from the higher pressure unit. RB-8530 Rupture disks or other non-reclosing devices may be used as sole relieving devices or in combination with safety relief valves to protect pressure vessels. Hot-Water Heating Boilers and Water Heaters a. These units generally do not use any water treatment and therefore may be more prone to problems with deposits forming which may impair a safety device’s operation. Particular attention should be paid to signs of leakage through valves or buildups of deposits. The selection of the correct rupture disk device for the intended service is critical to obtaining acceptable disk performance. Different disk designs are intended for constant pressure, varying pressure or pulsating pressure. Some designs include features that make them suitable for back pressure and/or internal vacuum in the pressure vessel. b. Hot-water boilers tend to have buildups of corrosion products since the system is closed with little makeup. These products can foul or block the valve inlet. The margin between the operating pressure and the burst pressure is an important factor in obtaining acceptable performance and service life of the disk. Flat and pre-bulged solid metal disks are typically used with an operating pressure which is no more than 60% to 70% of the burst pressure. Other designs are available that increase the operating pressure to as much as 90% of the burst pressure. Disks which have been exposed to pressures above the normal operating pressure for which they are designed are subject to fatigue or creep and may fail at unexpectedly low pressures. Disks used in cyclic service are also subject to fatigue and may require a greater operating margin or selection of a device suitable for such service. c. Water heaters will have cleaner water due to continuous makeup. However, these valves usually have a thermal element which will cause the valve to open slightly when the water is heated and not removed from the system. When this hot water evaporates in the discharge piping, calcium deposits may tend to form in the valve inlet and outlet. RB-8520 RUPTURE DISKS PRESSURE VESSELS AND PIPING Standard practice for overpressure protection devices is to not permit any type of isolation valve either before or after the device. However, some pressure vessel standards permit isolation valves under certain controlled conditions when shutting down of the vessel to repair a damaged or leaking valve would be difficult. If isolation block valves are employed, their use should be carefully controlled by written procedures and the block valves should have provisions to be either car-sealed or locked in an open position when not being used. For ASME Section VIII, Div. 1 pressure vessels, see UG-135, Appendix M, and jurisdictional rules for more information. The disk material is also critical to obtaining acceptable service life from the disk. Disks are available in a variety of materials and coatings and materials which are unaffected by the process fluid should be used. Disks that experience corrosion may fail and open at an unexpectedly low pressure. Disk designs must also be properly selected for the fluid state. Some disk types are not suitable for use in liquid service. Some disks may have a different flow resistance when used in liquid service which may affect the sizing of the disk. 81 NATIONAL BOARD INSPECTION CODE Information from the rupture disk manufacturer, including catalog data and installation instructions, should be consulted when selecting a disk for a particular service. disks shall be replaced if leakage through the disk is observed. e. If a rupture disk is used on a valve outlet, the valve design must be of a type not influenced by back pressure due to leakage through the valve. Otherwise, for nontoxic and non-hazardous fluids, the space between the valve and the ruptured disk shall be vented or drained to prevent the accumulation of pressure. For rupture disks and other non-reclosing devices, the following additional items should be considered during inspections. a. The rupture disk nameplate information, including stamped burst pressure and coincident temperature, should be checked to ensure it is compatible with the intended service. The coincident temperature on the rupture disk shall be the expected temperature of the disk when the disk is expected to burst and will usually be related to the process temperature, not the temperature on the pressure vessel nameplate. f. For rupture disks installed on the valve inlet, the installation should be reviewed to ensure that the combination rules of the original code of construction have been applied. A reduction in the valve capacity up to 10% is expected when used in combination with a non-reclosing device. g. The frequency of inspection for rupture disks and other non-reclosing devices is greatly dependent on the nature of the contents and operation of the system and only general recommendations can be given. Inspection frequency should be based on previous inspection history. If devices have been found to be leaking, defective or damaged by system contents during inspection, intervals should be shortened until acceptable inspection results are obtained. With this in mind, the inspection frequency guidelines specified in RB-8410(f) are suggested for similar services. b. Markings indicating direction of flow should be carefully checked to ensure they are correct. Some rupture disks when installed in the incorrect position may burst well above the stamped pressure. c. The marked burst pressure for a rupture disk installed at the inlet of a safety relief valve shall be equal to or less than the safety relief valve set pressure. A marked burst pressure of 90% to 100% of the safety relief valve set pressure is recommended. A disk with a non-fragmenting design which cannot affect the safety relief valve shall be used. Rupture disks are often used to isolate pressure relief valves from services where fouling or plugging of the valve inlet occurs. This tendency should be considered in establishing the inspection frequency. NOTE: If the safety relief valve set pressure is less than the vessel MAWP, the marked burst pressure may be higher than the valve set pressure, but no higher than the MAWP. Since these devices are for one time use, a visual inspection is the only inspection that can be performed. Rupture disks which are installed using a specified bolting torque procedure cannot be re-used after inspection and must be replaced. d. Check that the space between a rupture disk and a safety relief valve is supplied with a pressure gage, try cock or telltale indicator to indicate signs of leakage through the rupture disk. The safety relief valve shall be inspected and the leaking 82 PART RB — INSERVICE INSPECTION OF PRESSURE-RETAINING ITEMS It is recommended that all disks be periodically replaced to prevent unintended failure while in service due to deterioration of the device. RB-8600 RB-8700 INSERVICE INSPECTION ACTIVITIES Any defect or deficiency in the condition, operating and maintenance practices for pressure relief devices should be discussed with the owner or user at the time of inspection and, if necessary, recommendations made for the correction of such defect or deficiency. Follow-up inspections should be performed as needed to determine if deficiencies have been corrected satisfactorily. REQUIREMENTS FOR SHIPPING AND TRANSPORTING The improper shipment and transport of pressure relief devices can have detrimental affects on device operation. Pressure relief devices should be treated with the same precautions as instrumentation, with care taken to avoid rough handling or contamination prior to installation. RB-9000 METHODS FOR ESTIMATING REMAINING SERVICE LIFE AND INSPECTION INTERVALS RB-9010 SCOPE The following practices are recommended: a. Flanged valves should be securely bolted to pallets in the vertical position to avoid side loads on guiding surfaces. New pressure-retaining items are placed in service to operate under their intended design for a period of time determined by the service conditions, which can include exposure to corrosion, creep or other forms of degradation. If the pressure-retaining item is to remain safe in operation, the allowable conditions of service and the length of time before the next inspection must be identified. There are various methods that can be used to assess the condition of a pressure-retaining item to establish remaining service life and to ultimately determine the next inspection interval. In some cases, a visual inspection of the pressure-retaining item will suffice. However, more comprehensive condition assessment methods may be required, up to and including a comprehensive engineering evaluation performed by a competent technical source. b. Threaded valves should be securely packaged and cushioned during transport. c. Valve inlet and outlet connection, drain connections and bonnet vents should be protected during shipment and storage to avoid internal contamination of the valve. Ensure all covers and/or plugs are removed prior to installation. d. Lifting levers should be wired or secured so they cannot be moved while the valve is being shipped or stored. These wires shall be removed before the valve is placed in service. e. Rupture disks should be carefully checked for damage prior to installation and handled by the disk edges, if possible. Any damage to the surface of the disk can affect the burst pressure. 83 NATIONAL BOARD INSPECTION CODE RB-9100 NOTE: The lower temperature limit for the creep range for carbon steel is at least 700°F (370°C). The limit for alloy steel is often higher. The limit for other metals depends upon the specific material composition. Specialized metallurgical advice should be obtained for alloy steels and non-ferrous metals. CONDITIONS THAT AFFECT REMAINING SERVICE LIFE There are a variety of conditions that may affect the remaining service life of a pressureretaining item. These should be evaluated and the inspection interval reviewed for possible adjustment. The common conditions are listed below: 4. The pressure-retaining item is protected against inadvertent contamination. a. Deterioration This includes bulging, sagging, stress corrosion cracking, corrosion pitting (local or general), creep rupture, thermal or mechanical fatigue, hydrogen blistering, high temperature hydrogen attack, carburization, graphitization or erosion. Deterioration may also be caused by mechanical forces such as thermal shock, cyclic temperature changes, vibration, pressure surges, excessive temperature, external loading and faulty material and fabrication. RB-9110 METHOD FOR ESTIMATING REMAINING SERVICE LIFE FOR EXPOSURE TO ELEVATED TEMPERATURE When creep damage is suspected in a pressure-retaining item, an assessment of remaining service life should be discussed with the owner-user. This assessment may include but is not limited to the following methods: b. Corrosion Rate Not a Consideration When the corrosion rate of a pressure-retaining item is known to be zero, the item need not be inspected internally provided all of the following conditions are met and complete external inspections, including thickness measurements, are made periodically on the vessel: a. Dimensional measurements of the item to check for creep swell. b. Measurement of oxide scale and wall thickness for use in engineering analysis to determine remaining service life. Creep life can be predicted through an empirical approach which uses available data for the pressure-retaining component. Total number of operating hours to the present is needed. Oxide scale thickness (steam side) can be measured directly from material samples or be measured in situ using ultrasonic techniques. 1. The noncorrosive character of the content, including the effect of trace components, has been established by at least five years comparable service experience with the fluid being handled. 2. No questionable condition is disclosed by the periodic external inspection. c. Metallographic examination to determine the extent of exposure to creep damage in service. 3. The operating temperature of the pressure-retaining item does not exceed the lower limits for the creep range of the vessel metal. d. Removal of a material sample for creep rupture testing. A test matrix is selected to yield the most meaningful results from the 84 PART RB — INSERVICE INSPECTION OF PRESSURE-RETAINING ITEMS material sample. Test specimens are machined from the sample and tested under representative loads and temperatures (as selected in the test matrix). Creep strain vs. time and temperature vs. time to rupture data are recorded. RB-9120 METHOD FOR ESTIMATING INSPECTION INTERVAL FOR EXPOSURE TO ELEVATED TEMPERATURE b. When it is impossible to determine thickness by nondestructive means, a hole may be drilled through the metal wall and thickness gage measurements taken. For new pressure-retaining items for which service conditions are being changed, one of the following methods shall be employed to determine the probable rate of corrosion from which the remaining wall thickness, at the time of the next inspection, can be estimated: a. The corrosion rate as established by data collected by the owner or user on pressure-retaining items in the same or similar service; �� t(required)= minimum allowable thickness in inches (mm) for the limiting section of the pressure vessel or zone. It shall be the greater of the following: The minimum thickness permitted by the provision of the applicable section of the original code of construction. a. If suitably located existing openings are available, measurements may be taken through the openings. When the pressure-retaining item is exposed to service temperatures below the creep range and the corrosion rate controls the remaining service life of the pressure-retaining item, the remaining life shall be calculated by the formula below or by other industry acceptable methods as approved by the jurisdictional authority. thickness in inches (mm) measured at the time of inspection for the limiting section used in the determination of t(required). 2. Any suitable nondestructive examination method may be used to obtain thickness measurements provided the instruments employed are calibrated in accordance with the manufacturer’s specification or an acceptable national standard. METHOD FOR ESTIMATING REMAINING SERVICE LIFE FOR EXPOSURE TO CORROSION t(actual) = The calculated thickness, exclusive of the corrosion allowance, required for the pressure relieving device set pressure, static head or other loading and design temperature, or Corrosion Rate = inches (mm) per year of metal removal as a result of corrosion. The Inspector is cautioned to seek competent technical advice to determine which of the above condition assessment methods can be used to assure safe operation of the pressureretaining item and determination of the next inspection interval. RB-9130 1. b. If data for the same or similar service are not available, the corrosion rate as estimated from the Inspector’s knowledge and experience with pressure-retaining items in similar service; c. If the probable corrosion rate cannot be determined by either of the above methods, on-stream thickness determinations shall 85 NATIONAL BOARD INSPECTION CODE be made after approximately 1,000 hours of service. Subsequent sets of thickness measurements shall be taken after additional similar intervals until the corrosion rate is established. ports. It is not necessary to remove any insulation if the temperature of the entire pressure vessel shell is maintained sufficiently low or sufficiently high to preclude the presence of water. Pressure vessels which are known to have a remaining life of over ten years, or which are prevented from being exposed to external corrosion (such as being installed in a cold box in which the atmosphere is purged with an inert gas or by the temperature being maintained sufficiently low or sufficiently high to preclude the presence of water), need not have the insulation removed for the external inspection. However, the condition of the insulating system and/or the outer jacketing, such as the cold box shell, shall be observed periodically and repaired if necessary. Corrosion Resistant Lining When part or all of the pressure-retaining item has a corrosion resistant lining, the interval between inspections of those sections so protected may be based on recorded experience with the same type of lining in similar service, but shall not exceed ten years. If there is no experience on which to base the interval between inspections, performance of the liner shall be monitored by a suitable means such as the use of removable corrosion probes of the same material as the lining, ultrasonic examination or radiography. To check the effectiveness of an internal insulation liner, metal temperatures may be obtained by surveying the pressure vessel with temperature measuring or indicating devices. Interrupted Service The periods for inspection referred above, assume that the pressure-retaining item is in continuous operation, interrupted only by normal shutdown intervals. If a pressure-retaining item is out of service for an extended interval, the effect of the environmental conditions during such an interval shall be considered. Two or More Zones When a pressure-retaining item has two or more zones and the required thickness, corrosion allowance or corrosion rate differ so much that the foregoing provisions give significant differences in maximum periods between inspections for the respective zones (e.g., the upper and lower portions of some fractionating towers), the period between inspections may be established individually for each zone on the basis of the condition applicable thereto, instead of being established for the entire vessel on the basis of the zone requiring the more frequent inspection. If the pressure-retaining item was improperly stored, exposed to a detrimental environment or the condition is suspect, it shall be given an inspection before being placed into service. The date of next inspection, which was established at the previous inspection, may need to be revised if deterioration occurred during the period of interrupted service. Circumferential Stresses For a corroded area of considerable size in which the circumferential stresses govern the MAWP, the least thicknesses along the most critical plane of such area may be averaged over a length not exceeding: Above-Ground Vessels All pressure vessels above ground shall be given an external examination after operating the lesser of five years or quarter life, preferably while in operation. Inspection shall include determining the condition of the exterior insulation, the supports and the general alignment of the vessel on its sup- a. The lesser of one-half the pressure vessel diameter, or 20 in. (500 mm) for vessels 86 PART RB — INSERVICE INSPECTION OF PRESSURE-RETAINING ITEMS with inside diameters of 60 in. (1500 mm) or less, or weld, an independent calculation using the appropriate weld, joint efficiency factor must be made to determine if the thickness at the weld or remote from the weld, governs the maximum allowable working pressure. For the purpose of this calculation, the surface at a weld includes 1 in. (25 mm) on either side of the weld, or two times the minimum thickness on either side of the weld, whichever is greater. b. The lesser of one-third the pressure vessel diameter, or 40 in. (1000 mm), for vessels with inside diameters greater than 60 in. (1500 mm), except that if the area contains an opening, the distance within which thicknesses are averaged on either side of such opening, shall not extend beyond the limits of reinforcement as defined in the section of the ASME Code for ASME Stamped vessels and for other vessels in their applicable Codes of Construction. Ellipsoidal and Torispherical Heads a. When measuring the corroded thickness of ellipsoidal and torispherical heads, the governing thickness may be: Longitudinal Stresses If because of wind loads or other factors the longitudinal stresses would be of importance, the least thicknesses in a length of arc in the most critical plane perpendicular to the axis of the pressure vessel shall be averaged for computation of the longitudinal stresses. The thicknesses used for determining corrosion rates at the respective locations shall be the most critical value of average thickness. 1. that of the knuckle region with the head rating calculated by the appropriate head formula; or 2. that of the central portion of the dished region, in which case the dished region may be considered a spherical segment, whose allowable pressure is calculated by the formula for spherical shells in the ASME Code for ASME stamped vessels and for other vessels in their applicable Codes of Construction. Pitting Widely scattered pits may be disregarded provided that: a. Their depth is not more than one-half the required thickness of the pressure-retaining item wall (exclusive of corrosion allowance); b. The spherical segment of both ellipsoidal and torispherical heads shall be considered to be that area located entirely within a circle whose diameter is equal to 80% of the shell diameter. The radius of the dish of a torispherical head is to be used b. The total area of the pits does not exceed 7 sq. in. (4,500 mm2) within any 8 in. (200 mm) diameter circle; and c. The sum of their dimensions along any straight line within this circle does not exceed 2 in. (50 mm). TABLE RB-9130-1 Values of Spherical Radius Factor, K1 Weld Joint Efficiency Factor When the surface at a weld having a joint efficiency factor of other than one (1) is corroded, as well as surfaces remote from the K1D = Equivalent spherical radius D/2h = axis ratio (Interpolation permitted for intermediate values.) D/2h – 3.00 2.80 2.60 2.40 2.20 2.00 1.80 1.60 1.40 1.20 1.00 K1 – 1.36 1.27 1.18 1.08 0.99 0.90 0.81 0.73 0.65 0.57 0.50 87 NATIONAL BOARD INSPECTION CODE as the radius of the segment (equal to the diameter of the shell for standard heads, though other radii have been permitted). The radius of the spherical segment of ellipsoidal heads shall be considered to be the equivalent spherical radius K1D where D is the inside diameter of the shell (equal to the major axis) and K1 is given in Table RB-9130-1. In the table, h is onehalf the length of the minor axis (equal to the inside depth of the ellipsoidal head) measured from the tangent line (headbend line). For many ellipsoidal heads, D/2h = 2.0. less. Where the remaining service life is less than four years, the inspection interval may be the full remaining safe operating life up to a maximum of two years. Adjustments in Corrosion Rate If, upon measuring the wall thickness at any inspection, it is found that an inaccurate rate of corrosion has been assumed, the corrosion rate to be used for determining the inspection frequency shall be adjusted to conform with the actual rate found. Riveted Pressure Vessels For a pressure vessel with riveted joints, in which the strength of one or more of the joints is a governing factor in establishing the maximum allowable working pressure, consideration shall be given as to whether and to what extent corrosion will change the possible modes of failure through such joints. Also, even though no additional thickness may have originally been provided for corrosion allowance at such joints, credit may be taken for the corrosion allowance inherent in the joint design. RB-9140 METHOD FOR ESTIMATING INSPECTION INTERVAL FOR EXPOSURE TO CORROSION The maximum period between internal inspections or a complete inservice evaluation of pressure-retaining items shall not exceed one-half of the estimated remaining service life of the vessel or ten years, whichever is 88 Repairs and Alterations of Pressure-Retaining Items Part RC 89 NATIONAL BOARD INSPECTION CODE PART RC — REPAIRS AND ALTERATIONS OF PRESSURE-RETAINING ITEMS TABLE OF CONTENTS RC-1000 RC-1010 RC-1020 RC-1030 RC-1040 RC-1050 RC-1060 RC-1070 RC-1090 General Requirements ....................................................................................... 91 Scope ..................................................................................................................... 91 Construction Standards ..................................................................................... 91 Accreditation ....................................................................................................... 91 Materials .............................................................................................................. 91 Replacement Parts .............................................................................................. 91 Authorization ...................................................................................................... 92 Inspector............................................................................................................... 92 Welding ................................................................................................................ 93 RC-1100 RC-1110 RC-1120 RC-1130 RC-1140 RC-1150 Heat Treatment.................................................................................................... 94 Nondestructive Examination ............................................................................ 94 Pressure Gages, Measurement, Examination and Test Equipment ............. 95 Acceptance Inspection ....................................................................................... 95 Stamping .............................................................................................................. 95 Registration of Documentation ........................................................................ 95 RC-2000 RC-2010 RC-2020 RC-2030 RC-2050 RC-2060 RC-2070 RC-2080 Additional Requirements for Repairs.............................................................. 96 Scope ..................................................................................................................... 96 Drawings.............................................................................................................. 96 Authorization ...................................................................................................... 96 Examination and Test ......................................................................................... 97 Stamping .............................................................................................................. 98 Documentation.................................................................................................... 98 Repair of ASME Code Section VIII, Division 2, Pressure Vessels ................ 99 RC-3000 RC-3010 RC-3020 RC-3030 RC-3040 RC-3050 Additional Requirements for Alterations ..................................................... 100 Scope ................................................................................................................... 100 Design................................................................................................................. 100 Examination and Test ....................................................................................... 101 Stamping ............................................................................................................ 103 Documentation.................................................................................................. 103 90 PART RC — REPAIRS AND ALTERATIONS OF PRESSURE-RETAINING ITEMS RC-1000 GENERAL REQUIREMENTS RC-1040 RC-1010 SCOPE The materials used in making repairs or alterations shall conform to the original code of construction including the material A04 specification requirements. Carbon or alloy steel having a carbon content of more than 0.35% shall not be welded unless permitted by the original code of construction. The “R” Certificate Holder is responsible for verifying identification of existing materials from original data, drawings or units records and identification of the materials to be installed. Consideration shall be given to the condition of the existing material, especially in the weld preparation area. This part provides general requirements that apply to repairs and alterations to pressure-retaining items and shall be used in conjunction with RC-2000 and RC-3000. RC-1020 CONSTRUCTION STANDARDS When the standard governing the original construction is the ASME Code, repairs and alterations shall conform, insofar as possible, to the section and edition of the ASME Code most applicable to the work planned. For corrugating rolls manufactured per the A04 requirements of paragraph UF-7 of Section VIII, Div. 1, restoration of worn corrugating roll surfaces by weld overlay is permitted for all classes of SA-649 forging material and an exception to the 0.35% carbon limit is permitted. The requirements to qualify welding procedures and welder performance shall be those in ASME Section IX for hard facing (water resistance) and corrosion resistance overlays. When the standard governing the original construction is not the ASME Code, repairs or alterations shall conform, insofar as possible, to the edition of the construction standard or specification most applicable to the work. Where this is not possible or practicable, it is permissible to use other codes, standards or specifications, including the ASME Code provided the “R” Certificate Holder has the concurrence of the Inspector and the jurisdiction where the pressure-retaining item is installed. RC-1030 MATERIALS RC-1050 REPLACEMENT PARTS Replacement parts which will be subject to internal or external pressure that consist of new materials which may be formed to the required shape by casting, spinning, forging, die forming and on which no fabrication welding is performed shall be supplied as material. Such parts shall be marked with the material and part identification and the name or trademark of the parts manufacturer. In lieu of full identification marking on the material or part, the part ACCREDITATION Organizations performing repairs or alterations shall be accredited as described in Part RA, as appropriate for the scope of work to be performed. 91 NATIONAL BOARD INSPECTION CODE manufacturer may use a coded marking system traceable to the original marking. Such markings shall be considered as the parts manufacturer ’s certification that the part complies with the original code of construction. Examples include seamless or welded tubes or pipe, forged nozzles, heads or tube sheets or subassemblies attached together mechanically. construction. Certification to the original code of construction as required by the original code of construction or equivalent shall be supplied with the item. When this is not possible or practicable, the organization fabricating the part may have a National Board Certificate of Authorization; replacement parts shall be documented on Form R-3 and the “R” symbol stamp applied as described in Appendix 2. Replacement parts which will be subject to internal or external pressure that are preassembled by attachment welds shall have the welding performed in accordance with the original code of construction. The supplier or manufacturer shall certify that the material and fabrication are in accordance with the original code of construction. This certification shall be supplied in the form of bills of material and drawings with statement of certification. Examples include boiler furnace wall or floor panel assemblies, prefabricated openings in boiler furnace walls, such as burner openings, air ports, inspection openings or sootblower openings. RC-1060 AUTHORIZATION The Inspector’s authorization to perform a repair or alteration shall be obtained prior to initiation of a repair or alteration to a pressure-retaining item. RC-1070 INSPECTOR Inspection and certification shall be made by an Inspector employed by one of the following: a. A Jurisdictional Authorized Inspection Agency, When ASME is the original code of construction, replacement parts subject to internal or external pressure fabricated by welding, which require shop inspection by an Authorized Inspector shall be fabricated by an organization having an appropriate ASME Certificate of Authorization. The item shall be inspected and stamped as required by the applicable section of the ASME Code. A completed ASME Manufacturer’s Partial Data Report shall be supplied by the manufacturer. b. The Authorized Inspection Agency of the “R” Certificate Holder making the repair or alteration, c. The Authorized Inspection Agency which insures the pressure-retaining item, or d. The Owner-User Inspection Organization. An Inspector employed by an Owner-User Inspection Organization may authorize and accept work only on pressure-retaining items owned-used by the company. The company’s organization and inspection procedures shall have the specific approval of the Jurisdiction or in the absence of a Jurisdiction, by the National Board. When the original code of construction is other than ASME, replacement parts subject to internal or external pressure, fabricated by welding shall be manufactured by an organization certified as required by the original code of construction. The item shall be inspected and stamped as required by the original code of 92 PART RC — REPAIRS AND ALTERATIONS OF PRESSURE-RETAINING ITEMS RC-1090 WELDING RC-1094 Welding shall be performed in accordance with the requirements of the original code of construction used for the pressure-retaining item. RC-1091 The “R” Certificate Holder shall maintain a record of the results obtained in welding procedure qualifications, except for those qualifications for which the provisions of RC-1092 are used and of the results obtained in welding performance qualifications. These records shall be certified by the “R” Certificate Holder and shall be available to the inspector. WELDING PROCEDURE SPECIFICATIONS Welding shall be performed in accordance with Welding Procedure Specifications (WPS) qualified in accordance with the original code of construction. When this is not possible or practicable, the WPS may be qualified in accordance with Section IX of the ASME Code. RC-1092 RC-1095 WELDERS’ IDENTIFICATION The “R” Certificate Holder shall establish a system for the assignment of a unique identification mark to each welder/welding operator qualified in accordance with the requirements of the NBIC. The “R” Certificate Holder shall also establish a written procedure whereby all welded joints can be identified as to the welder or welding operator who made them. This procedure shall use one or more of the following methods and be acceptable to the Inspector. The welder’s or welding operator’s identification mark may be stamped (low stress stamp) adjacent to all welded joints made by the individual or, in lieu of stamping, the “R” Certificate Holder may keep a record of welded joints and the welders or welding operators used in making the joints. STANDARD WELDING PROCEDURE SPECIFICATIONS An “R” Certificate Holder may use one or more applicable Standard Welding Procedure A04 Specifications shown in Appendix A without supporting procedure qualification records (PQRs) since SWPs are prequalified and the PQR will not be supplied. RC-1093 WELDING RECORDS PERFORMANCE QUALIFICATION Welders or welding operators shall be qualified for the welding processes that are used. Such qualification shall be in accordance with the requirements of the original code of construction or Section IX of the ASME Code. Use of Standard Welding Procedure Specification shown in Appendix A is permitted for performance qualification testing. RC-1096 WELDERS’ CONTINUITY The performance qualification of a welder or welding operator shall be affected when one of the following conditions occur: a. When the welder or welding operator has not welded using a specific process during a period of six (6) months or more, their qualifications for that process shall expire. 93 NATIONAL BOARD INSPECTION CODE b. When there is specific reason to question their ability to make welds that meet the specification, the qualification which supports the welding that is being performed shall be revoked. All other qualifications not questioned remain in effect. impractical. In such instances, alternative methods of postweld heat treatment or special welding methods acceptable to the Inspector may be used. Methods which may be used as alternatives to postweld heat treatment are described in Part RD. RC-1100 HEAT TREATMENT RC-1110 RC-1101 PREHEATING The nondestructive examination (NDE) requirements, including technique, extent of coverage, procedures, personnel qualification and acceptance criteria, shall be in accordance with the original code of construction used for construction of the pressure-retaining item. Weld repairs and alterations shall be subjected to the same nondestructive examination requirements as the original welds. Where this is not possible or practicable, alternative NDE methods acceptable to the Inspector and the jurisdiction where the pressure-retaining item is installed, where required, may be used. Preheating may be employed during welding to assist in completion of the welded joint (Appendix B). The need for and the temperature of preheat are dependent on a number of factors such as chemical analysis, degree of restraint of the items being joined, material thickness and mechanical properties. The welding procedure specification for the material being welded shall specify the preheat temperature requirements. RC-1102 NDE personnel shall be qualified and certi- A04 fied in accordance with the requirements of the original code of construction. When this is not possible or practicable, NDE personnel may be qualified and certified in accordance with their employer’s written practice. ASNT SNT-TC-1A, Recommended Practice for Nondestructive Testing Personnel Qualification and Certification (2001 edition), or ASNTCP-189, Standard for Qualification and Certification of Nondestructive Testing Personnel (2001 edition), shall be used as a guideline for employers to establish their written practice. The ASNT Central Certification Program (ACCP, Rev. 3, Nov. 1997) may be used to fulfill the examination and demonstration requirements of SNTTC-1A and the employer’s written practice. Provisions for qualification and certification of NDE personnel shall be described in the “R” Certificate Holder’s written quality system. POSTWELD HEAT TREATMENT Postweld heat treatment shall be performed as required by the original code of construction in accordance with a written procedure. The procedure shall contain the parameters for postweld heat treatment. Local PWHT that is not specified by the original code of construction may be performed in accordance with an Alternative Post Weld Heat Treatment Method described in RD-1070 with acceptance by the Inspector and, when required, by the Jurisdiction. RC-1103 NONDESTRUCTIVE EXAMINATION ALTERNATIVE POSTWELD HEAT TREATMENT METHODS Under certain conditions, postweld heat treatment in accordance with the original code of construction may be inadvisable or 94 PART RC — REPAIRS AND ALTERATIONS OF PRESSURE-RETAINING ITEMS RC-1120 or the construction portion of the alteration shall apply the stamping. For a re-rating where no physical changes are made to the pressure-retaining item, the “R” Certificate Holder responsible for design shall apply the stamping. Required stamping and nameplate information is shown in Appendix 2. PRESSURE GAGES, MEASUREMENT, EXAMINATION AND TEST EQUIPMENT The calibration of pressure gages, measurement, examination and test equipment and documentation of calibration shall be performed as required by the applicable standard used for construction. RC-1130 RC-1141 If it becomes necessary to remove the original stamping, the Inspector shall, subject to the approval of the Jurisdiction, witness the making of a facsimile of the stamping, the obliteration of the old stamping and the transfer of the stamping to the new item. When the stamping is on a nameplate, the Inspector shall witness the transfer of the nameplate to the new location. Any relocation shall be described on the applicable NBIC “R” Form. ASME Code items shall not be restamped with the ASME Code Symbol. ACCEPTANCE INSPECTION The Inspector making the acceptance inspection shall be the same inspector who authorized the repair or alteration. Where this is not possible or practicable, another Inspector may perform the acceptance inspection; however, in all cases, the Inspector who performs the acceptance inspection shall be an employee of the same organization as the Inspector who authorized the repair or alteration. Before signing the appropriate NBIC Report Form, the Inspector shall review the drawings, assure the repair or alteration was performed in accordance with the acceptable code of construction or standard, witness any pressure test or any acceptable alternative test method applied, assure that the required nondestructive examinations have been performed satisfactorily and that the other functions necessary to assure compliance with the requirements of this Code have been performed. RC-1140 REMOVAL OF ORIGINAL STAMPING OR NAMEPLATE RC-1150 REGISTRATION OF “R” FORMS Organizations performing repairs or alterations under an “R” stamp program may register such repairs or alterations with the National Board. It should be noted that some jurisdictions may require registration of repairs and alterations with the National Board. For those “R” Forms not registered with the National Board, the organization performing repairs or alterations shall retain a copy of the “R” Form on file for a minimum period of five years. STAMPING The stamping of or attaching of a nameplate to, a pressure-retaining item shall indicate that the work was performed in accordance with the requirements of this Code. Such stamping or attaching of a nameplate shall be done only with the knowledge and authorization of the Inspector. The “R” Certificate Holder responsible for the repair 95 NATIONAL BOARD INSPECTION CODE RC-1151 repairs provided the Inspector assures that the “R” Certificate Holder has acceptable procedures covering the repairs. FORM R LOG The “R” Certificate Holder shall maintain a single, sequential log of “R” Form numbers assigned for NBIC Report Forms (i.e., R-1, R-2 and R-3) that are registered with the National Board. RC-2031 ROUTINE REPAIRS RC-2000 ADDITIONAL REQUIREMENTS FOR REPAIRS Prior to performing routine repairs, the “R” Certificate Holder should determine that routine repairs are acceptable to the jurisdiction where the pressure-retaining item is installed. RC-2010 SCOPE a. The four categories of routine repairs are: This section provides additional requirements for repairs to pressure-retaining items and shall be used in conjunction with RC-1000. A04 RC-2020 1. Welded repairs or replacements of tubes or pipes NPS 5 (DN 125) and A04 smaller, or sections thereof, where neither postweld heat treatment nor NDE other than visual examination is required by the original code of construction. DEFECT REPAIRS Before a repair is made to a defect in a welded joint or base metal, care should be taken to investigate its cause and to determine its extent and likelihood of recurrance. RC-2021 2. The addition or repair of non-load bearing attachments to pressure retaining items where postweld heat treatment is not required. 3. Weld buildup of wasted areas in shells and heads not exceeding 100 sq. in. (65,000 sq. mm) or 25% of nominal wall thickness or 1/2 in. (13 mm), whichever is less. DRAWINGS As appropriate, drawings shall be prepared to describe the repair. Drawings shall include sufficient information to satisfactorily perform the repair. 4. Corrosion resistance weld overlay not exceeding 100 sq. in. (65,000 sq.mm). Repairs to pressure-retaining items shall not be initiated without the authorization of the Inspector, who shall determine that the repair methods are acceptable. b. Routine repairs shall be performed under the “R” Certificate Holder’s quality system program; however, the requirement for in-process involvement of the Inspector and stamping may be waived. See RC-2060. Subject to acceptance of the Jurisdiction, the Inspector may give prior approval for routine c. The process of identifying, controlling and implementing routine repairs shall RC-2030 AUTHORIZATION 96 PART RC — REPAIRS AND ALTERATIONS OF PRESSURE-RETAINING ITEMS be documented in the “R” Certificate Holder’s quality system program. RC-2050 The following requirements shall apply to all repairs to pressure-retaining items: d. Routine repairs shall be documented on a Form R-1 with a statement on line 10, Remarks: “Routine Repair”. RC-2032 PARTS EXAMINATION AND TEST a. The integrity of repairs and replacement parts used in repairs shall be verified by examination or test. WELD REPAIRS TO PRESSURE RELIEF VALVE b. The “R” Certificate Holder is responsible for all activities relating to examination and test of repairs. Prior to performing weld repairs to pressure relief valve (PRV) parts, the “R” Certificate Holder shall receive repair information required by RA-2255(j) from the “VR” Certificate Holder responsible for the pressure relief valve repair. c. Examinations and tests to be used shall be subject to acceptance of the Inspector and where required, acceptance of the jurisdiction. a. PRV part weld repairs shall be performed under the “R” Certificate Holder’s quality system; however, the requirements for in-process involvement of the Inspector (RC-1130) may be waived. The requirement for stamping is waived. RC-2051 METHODS Based on the nature and scope of the repair activity, one or a combination of the following examination and test methods shall be applied to repairs and replacement parts used in repairs. b. The process of identifying and controlling repairs shall be documented in the “R” Certificate Holder’s quality system. a. Liquid Pressure Test Pressure testing of repairs shall meet the following requirements: c. PRV part repairs shall be documented on a Form R-1 with a statement under Remarks “PRV Part Repair.” The owner’s name and location of installation shall be that of the “VR” Certificate Holder. The information received from the “VR” Certificate Holder (RA-2255(j)) shall be noted under Description of Work. 1. Pressure tests shall be conducted using water or other liquid medium. The test pressure shall be the minimum required to verify the leak tightness integrity of the repair, but not more than 150% of the maximum allowable working pressure (MAWP) stamped on the pressure-retaining items, as adjusted for temperature. When original test pressure included consideration of corrosion allowance, the test pressure may be further adjusted based on the remaining corrosion allowance. d. Upon completion of the repair, the repaired part and completed Form R-1 shall be returned to the “VR” Certificate Holder responsible for completing the PRV repair. 97 NATIONAL BOARD INSPECTION CODE 2. During a pressure test where the test pressure will exceed 90% of the set pressure of the pressure relief device, the device shall be removed whenever posssible. If not possible, a test gag may be used following the valve manufacturer’s instructions and recommendations. Extreme caution should be employed to ensure only enough force is applied to contain pressure. Excessive mechanical force applied to the test gag may result in damage to the seat and/or spindle and may interfere with the proper operation of the valve. The test gag shall be removed following the test. shall be the minimum required to verify leak tightness integrity of the repair, but shall not exceed the maximum pneumatic test pressure of the original code of construction. Precautionary requirements of the original code of construction shall be followed. c. Initial Service Leak Test When an initial service leak test is permitted by the original code of construction, such testing may also be used to verify the leak tightness integrity of repairs. d. Vacuum Test A vacuum test may be conducted. Vacuum test methods used shall be suit-able to verify the leak tightness integrity of the repair. 3. The metal temperature for the pressure test shall be in accordance with the original code of construction, but not less than 60°F (16°C) unless the owner provides information on the toughness characteristics of the material to indicate the acceptability of a lower test temperature. During close examination the metal temperature shall not exceed 120°F (50°C) unless the owner specified requirements for a higher test temperature and it is acceptable to the Inspector. e. Nondestructive Examination Nondestructive examination (NDE) may be conducted. NDE methods used shall be suitable for providing meaningful results to verify the integrity of the repair. RC-2060 STAMPING Pressure-retaining items repaired in accordance with the NBIC shall be stamped as required by Appendix 2. 4. Hold-time for the pressure test shall be a minimum of 10 minutes prior to examination by the Inspector. Where the test pressure exceeds the MAWP of the item, the test pressure shall be reduced to the MAWP for close examination by the Inspector. Holdtime for close examination shall be as necessary for the Inspector to conduct the examination. Subject to the acceptance of the jurisdiction and the concurrence of the Inspector, nameplates and stamping may not be required for routine repairs (RC-2031). In all cases, the type and extent of repairs necessary shall be considered prior to waiving the requirement. b. Pneumatic Test A pneumatic test may be conducted. Concurrence of the owner shall be obtained in addition to that of the Inspector and jurisdiction where required. The test pressure RC-2070 DOCUMENTATION Repairs that have been performed in accordance with the NBIC shall be documented 98 PART RC — REPAIRS AND ALTERATIONS OF PRESSURE-RETAINING ITEMS on Form R-1 Report of Repair, as shown in Appendix 5. Form R-4 Report Supplementary Sheet shall be used to record additional data when space is insufficient on Form R-1. RC-2071 RC-2080 REPAIR OF ASME CODE SECTION VIII, DIVISION 2 OR 3, PRESSURE VESSELS RC-2081 PREPARATION OF FORM R-1 The following requirements shall apply for the A04 repair of pressure vessels constructed to the requirements of Section VIII, Division 2 or 3, of the ASME Code. Preparation of Form R-1 shall be the responsibility of the “R” Certificate Holder performing the repair. An Inspector shall indicate acceptance by signing the Form R-1. RC-2082 a. Professional Engineer Review The repair plan shall be reviewed and certified by a Professional Engineer who is registered in one or more of the states of the United States of America or the provinces of Canada is experienced in pressure vessel design and is knowledgeable in ASME A04 Section VIII, Div. 2 or 3 as applicable. The review and certification shall be such as to ensure the work involved in the repair is compatible with the user ’s design specification and the manufacturer ’s design report. DISTRIBUTION Legible copies of the completed Form R-1, together with attachments, shall be distributed to the owner or user, the Inspector, the jurisdiction, if required, and the Authorized Inspection Agency responsible for inservice inspection. Distribution of Form R-1 and attachments shall be the responsibility of the organization performing the repair. RC-2073 REPAIR PLAN The user shall prepare or cause to have prepared a detailed plan covering the scope of the repair. The Form R-3 and the manufacturer’s data reports described in RC-1050 shall be a part of the completed Form R-1 and shall be attached thereto. RC-2072 SCOPE b. Authorized Inspection Agency Acceptance Following review and certification, the repair plan shall be submitted for acceptance to the Authorized Inspection Agency/Owner-User Inspection Organization whose Inspector will make the acceptance inspection and sign the Form R-1. REGISTRATION Form R-1 may be registered with the National Board as noted in RC-1150. 99 NATIONAL BOARD INSPECTION CODE RC-3000 RC-3010 ADDITIONAL REQUIREMENTS FOR ALTERATIONS RC-3022 SCOPE This section provides additional requirements for alterations to pressure-retaining items and shall be used in conjunction with RC-1000. RC-3020 DESIGN The “R” Certificate Holder performing alterations shall establish controls to ensure that all required design information, applicable drawings, design calculations, specifications and instructions are prepared, obtained, controlled and interpreted to provide the basis for an alteration in accordance with the original code of construction. When a Manufacturer’s Data Report is required by the original construction standard, a copy of the original Data Report shall be obtained for use in the design of the alteration. When the original Manufacturer’s Data Report cannot be obtained, agreements on the method of establishing design basis for the alteration shall be obtained from the Inspector and the jurisdiction. RC-3021 Re-rating of a pressure-retaining item by increasing the maximum allowable working pressure (internal or external) or temperature or decreasing the minimum temperature shall be done only after the following re q u i re m e n t s h a v e b e e n m e t t o t h e satisfaction of the jurisdiction at the location of the installation: a. Revised calculations verifying the new service conditions shall be prepared in accordance with the “R” Certificate Holder’s Quality Control System. Establishing a higher joint efficiency to re-rate a pressure-retaining item is not permitted. b. All re-ratings shall be established in accordance with the requirements of the construction standard to which the pressure-retaining item was built. c. Current inspection records verify that the pressure-retaining item is satisfactory for the proposed service conditions. d. The pressure-retaining item has been pressure tested, as required, for the new service conditions. RC-3023 CALCULATIONS A set of calculations shall be completed prior to the start of any physical work. All design work shall be completed by an organization experienced in the design portion of the standard used for construction of the item. All calculations shall be made available for review by the Inspector accepting the design. RE-RATING 7 DRAWINGS As appropriate, drawings shall be prepared to describe the alteration. Drawings shall include sufficient information to satisfactorily perform the alteration. 7 100 Re-rating: Except as provided for Yankee Dryers in Appendix K, this code does not provide rules for derating boilers or pressure vessels; however, when the MAWP and/or allowable temperature of a boiler or pressure vessel is reduced, the jurisdiction wherein the object is installed should be contacted to determine if specific procedures should be followed. PART RC — REPAIRS AND ALTERATIONS OF PRESSURE-RETAINING ITEMS RC-3024 ALLOWABLE STRESSES For re-rating or re-calculating a new minimum wall thickness for a pressure-retaining item using a later edition/addenda of the original code of construction that permits use of higher allowable material stress values than were used in the original construction, the additional requirements of RD-3000 shall apply. A04 RC-3025 A04 RC-3026 ALTERATION OF ASME CODE SECTION VIII, DIVISION 2 OR 3 PRESSURE VESSELS SCOPE The following shall apply for the alteration of pressure vessels constructed to the requirements of Section VIII, Division 2 or 3 of the ASME Code. A04 RC-3027 ALTERATION PLAN Professional Engineer Review The alteration plan shall be reviewed and certified by a Professional Engineer who is registered in one or more of the states of the United States of America or the provinces of Canada, is experienced in pressure vessel design and is knowledgeable in ASME Section VIII, Div. 2 or 3 as applicable. The review and certification shall be such as to ensure the work involved in alteration is compatible with the user’s design specification and the manufacturer’s design report. User’s Design Specification If the alteration is such that the work is not compatible with or changes one or more requirement(s) of the original user’s design specification, the user’s design specification shall be revised by the user with the new parameters or changes. The revisions shall 101 be certified by a Professional Engineer who is registered in one or more of the states of the United States of America or the provinces of Canada, is experienced in pressure vessel design and is knowledgeable in ASME Section VIII, Div. 2 or 3 as applicable. Manufacturer’s Design Report The “R” Certificate Holder shall prepare or cause to have prepared a supplement to the manufacturer’s design report to reconcile the new parameters or changes with the user’s design specification. The supplement to the manufacturers design report shall be certified by a Professional Engineer who is registered in one or more of the states of the United States of America or the provinces of Canada, is experienced in pressure vessel design and is knowledgeable in ASME Section VIII, Div. 2 or 3 as applicable. Authorized Inspection Agency Acceptance Following review and certification, the alteration plan shall be submitted for acceptance to the Authorized Inspection Agency/OwnerUser Inspection Organization whose inspector will make the acceptance inspection and sign the Form R-2. RC-3030 EXAMINATION AND TEST The following requirements shall apply to all alterations to pressure-retaining items: a. The integrity of alterations and replacement parts used in alterations shall be verified by examination or test. b. The “R” Certificate Holder is responsible for all activities relating to examination and test of alterations. c. Examinations and tests to be used shall be subject to acceptance of the Inspector, and where required, acceptance of the Jurisdiction. NATIONAL BOARD INSPECTION CODE RC-3031 damage to the seat and/or spindle and may interfere with the proper operation of the valve. The test gag shall be removed following the test. METHODS Based on the nature and scope of the alterations activity, one or a combination of the following examination and test methods shall be applied to alterations and replacement parts used in alterations. 4. The metal temperature for the pressure test shall be in accordance with the original code of construction, but not less than 60°F (16°C) unless the owner provides information on the toughness characteristics of the material to indicate the acceptability of a lower test temperature. During close examination the metal temperature shall not exceed 120°F (50°C) unless the owner specifies requirements for a higher test temperature and it is acceptable to the Inspector. a. Liquid Pressure Test Pressure testing of alterations shall meet the following requirements: 1. A pressure test as required by the original code of construction shall be conducted. The test pressure shall not exceed 150% of the maximum allowable working pressure (MAWP) stamped on the pressure-retaining item, as adjusted for temperature. When the original test pressure included consideration of corrosion allowance, the test pressure may be further adjusted based on the remaining corrosion allowance. The pressure test for replacement parts may be performed at the point of manufacture or point of installation. 2. As an alternative to pressure testing connecting welds in accordance with the original code of construction, connecting welds may be tested or examined in accordance with the rules for repairs (see RC-2051). Connecting welds are defined as welds attaching the replacement part to the pressureretaining item. 3. During a pressure test where the test pressure will exceed 90% of the set pressure of the pressure relief device, the device shall be removed whenever possible. If not possible, a test gag may be used following the valve manufacturer’s instructions and recommendations. Extreme caution should be employed to ensure only enough force is applied to contain pressure. Excessive mechanical force applied to the test gag may result in 5. Hold-time for the pressure test shall be a minimum of 10 minutes prior to examination by the Inspector. The test pressure shall be reduced to the MAWP for close examination by the Inspector. Hold-time for close examination shall be as necessary for the Inspector to conduct the examination. b. Pneumatic Test A pneumatic test may be conducted when contamination of the pressure-retaining item by liquids is possible or when liquid pressure testing is not practicable. Concurrence of the owner shall be obtained in addition to the Inspector and jurisdiction where required. Pneumatic test requirements and precautions shall be in accordance with the original code of construction. c. Nondestructive Examination Nondestructive examination (NDE) may be conducted when contamination of the pressure-retaining item by liquids is possible or when pressure testing is not practicable. Concurrence of the owner shall be obtained in addition to the Inspector and jurisdiction where required. NDE methods used shall be suitable for providing meaningful results to verify the integrity of the alteration. 102 PART RC — REPAIRS AND ALTERATIONS OF PRESSURE-RETAINING ITEMS RC-3040 STAMPING Pressure-retaining items altered in accordance with this code shall have a nameplate or stamping applied adjacent to the original manufacturer’s stamping or nameplate in accordance with Appendix 2. For an alteration where physical changes are made to the pressure-retaining item, the “R” Certificate Holder responsible for the construction portion of the alteration shall apply the stamping or nameplate. For an alteration where no physical changes are made to the pressure-retaining item (e.g., a re-rating) the “R” Certificate Holder, assuming responsiblity for the design, shall apply the stamping or nameplate. RC-3050 DOCUMENTATION Alterations performed in accordance with the NBIC shall be documented on Form R-2, Report of Alteration, as shown in Appendix 5. Form R-4 Report Supplementary Sheet shall be used to record additional data when space is insufficient on Form R-2. RC-3051 inspector shall indicate that the work complies with the applicable requirements of this code by completing and signing the Certificate of Inspection section of the form. When no construction work is performed (e.g., a re-rating with no physical changes), the “R” Certificate Holder responsible for the design shall prepare the Form R-2, including the gathering and attaching of supporting reports. The following shall be attached to and become a part of the completed Form R-2: a. For ASME boilers and pressure vessels, a copy of the original Manufacturer’s Data Report, when available; b. Form R-3, Report of Parts Fabricated by Welding or Manufacturer’s Partial Data Reports, and; c. For other than ASME, the manufacturer’s reports (i.e., reports required by the original code of construction), when available. RC-3052 PREPARATION Initial preparation of Form R-2 shall be the responsibility of the “R” Certificate Holder responsible for the design portion of the alteration. The design organization shall complete and sign the “Design Certificate” section of the Form R-2. An inspector shall indicate acceptance of the design by signing the “Certificate of Design Change Review” section of the Form R-2. Final preparation of Form R-2, including the gathering and attaching of supporting reports, shall be the responsibility of the “R” Certificate Holder that performed the construction portion of the alteration. The construction organization shall complete the Form R-2 provided by the design organization, including the Construction Certificate section. An 103 DISTRIBUTION Distribution of the completed Form R-2 shall be the responsibility of the “R” Certificate Holder that performed the construction portion of the alteration. When no construction work is performed, (e.g., a re-rating with no physical changes), the “R” Certificate Holder responsible for the design shall distribute the form. Legible copies of the completed Form R-2, together with attachments, shall be distributed to the inspector, the authorized inspection agency responsible for the inservice inspection of the pressure-retaining item, the owneruser, the “R” Certificate Holder responsible for design and the jurisdiction if required. NATIONAL BOARD INSPECTION CODE RC-3053 REGISTRATION If the pressure-retaining item is registered with the National Board, an original Form R-2 together with attachments shall be registered with the National Board. A04 If the item is not registered with the National Board, one original Form R-2 together with attachments may be registered with the National Board or retained as required by RC-1150(b). 104 Repair/Alteration Methods Part RD 105 NATIONAL BOARD INSPECTION CODE PART RD — REPAIR/ALTERATION METHODS TABLE OF CONTENTS RD-1000 RD-1010 RD-1020 RD-1030 RD-1040 RD-1050 RD-1060 A04 RD-1070 Alternatives to Postweld Heat Treatment ..................................................... 107 Scope ................................................................................................................... 107 Nondestructive Examination of Welds.......................................................... 107 Welding Method 1 ............................................................................................ 107 Welding Method 2 ............................................................................................ 108 Welding Method 3 ........................................................................................... 110 Welding Method 4 ........................................................................................... 111 Wedling Method 5 .............................................................................................113 RD-1100 Alternative Local Post Weld Heat Treatment Method .................................115 RD-2000 RD-2010 RD-2020 RD-2030 RD-2040 RD-2050 RD-2060 RD-2070 Repair Methods ................................................................................................. 115 Scope ................................................................................................................... 115 Defect Repairs ................................................................................................... 116 Wasted Areas ..................................................................................................... 117 Seal Welding ...................................................................................................... 117 Re-Ending or Piecing Pipes or Tubes ............................................................. 117 Patches................................................................................................................ 117 Stays .................................................................................................................... 123 RD-3000 RD-3010 RD-3020 Alterations Based on Allowable Stress Values ..............................................123 Re-rating..............................................................................................................123 Minimum Wall Thickness.................................................................................124 106 PART RD — REPAIR/ALTERATION METHODS RD-1000 RD-1010 ALTERNATIVES TO POSTWELD HEAT TREATMENT RD-1020 SCOPE Under certain conditions, postweld heat treatment in accordance with the original code of construction may be inadvisable or impractical. In such instances, the following alternative methods may be used. Competent technical advice shall be obtained from the manufacturer of the pressure-retaining item or from another qualified source, such advice being especially necessary if the alternative is to be used in highly stressed areas, if service conditions are conducive to stress corrosion cracking, if materials are subject to hydrogen embrittlement or are operating at temperatures in the creep range or if the alternative is being considered for “on-stream” repairs or “hot tapping” on piping systems. Selection of the welding method used shall be based on the rules of the original code of construction together with the above mentioned advice concerning the adequacy of the weld in the as-welded condition at operating and pressure test conditions. When reference is made in this part to materials by the ASME designation, P-Number and Group Number, the requirements of this part apply to the applicable materials of the original code of construction, either ASME or other, which conform by chemical composition and mechanical properties to the ASME P-Number and Group Number designations. NONDESTRUCTIVE EXAMINATION OF WELDS Prior to welding, the area prepared for welding shall be examined using either the magnetic particle (MT) or the liquid penetrant (PT) examination method to determine that no defects exist. After the finished weld has reached ambient temperature, the weld shall be examined again by either of the above methods to determine that no defects exist using acceptance standards acceptable to the Inspector or original code of construction. In addition, welds greater than 3/8 in. (10 mm) deep or welds in a boiler, pressure vessel or piping systems that were originally required to be radiographed by the rules of the original code of construction, shall be radiographically examined. In situations where it is not practical to perform radiography, the accessible surfaces of each nonradiographed repair weld shall be fully examined using the MT or PT method to determine that no defects exist and the maximum allowable working pressure and/or allowable temperature shall be reevaluated to the satisfaction of the jurisdiction at the location of installation. RD-1030 WELDING METHOD 1 When using this method the following is required: a. This method may be used when the applicable rules of the original code of construction did not require notch toughness testing. b. The materials shall be limited to P-No. 1, Group 1, 2, and 3 and to P-No. 3, Group 1 and 2 (excluding Mn-Mo steels in Group 2), as permitted for welded construction by the applicable rules of the original code of construction. 107 NATIONAL BOARD INSPECTION CODE c. The welding shall be limited to the shielded metal-arc welding (SMAW), gas metal-arc welding (GMAW), fluxcored arc welding (FCAW) and gas tungsten-arc welding (GTAW) processes. d. The welders and welding procedures (WPS) shall be qualified in accordance with the applicable rules of the original code of construction, except that the postweld heat treatment of the test coupon used to qualify the weld procedure shall be omitted. e. The weld area shall be preheated and maintained at a minimum temperature of 300˚F (150˚C) during welding. The 300˚F (150˚C) temperature should be checked to assure that 4 in. (100 mm) of the material or four times the material thickness (whichever is greater) on each side of the groove (or full thickness of joint for a groove weld) is maintained at the minimum temperature during welding. The maximum interpass temperature shall not exceed 450˚F (230˚C). When the weld does not penetrate through the full thickness of the material, the minimum preheat and maximum interpass temperatures need only be maintained at a distance of 4 in. (100 mm) or four times the depth of the repair weld, whichever is greater on each side of the joint. RD-1040 WELDING METHOD 2 When using this method the following is required: a. This method shall be used when the applicable rules of the original code of construction required notch toughness testing or shall be used when the applicable rules of the original code of construction did not require notch toughness testing provided the adequacy of the notch toughness of the weld, including the heat-affected zone, in the as-welded condition at operating and pressure test conditions is verified. b. The materials shall be limited to carbon and low alloy steels permitted for welded construction by the applicable rules of the original code of construction, including those materials conforming to any of the following ASME P-No. designations: P-No. 1, Group 1, 2 and 3, P-No. 3, Group 1, 2 and 3, P-No. 4, P-No. 5A, P-No. 9A, P-No. 10A, P-No. 10B, P-No. 10C, P-No. 11A or P-No. 11B. c. The welding shall be limited to the shielded metal-arc welding (SMAW), gas metal-arc welding (GMAW), fluxcored arc welding (FCAW) and gas tungsten-arc welding (GTAW) processes. d. The welders and welding procedures (WPS) shall be qualified in accordance with the applicable rules of the original code of construction, except that the postweld heat treatment of the test coupon used to qualify the weld procedure shall be omitted. The WPS shall be qualified for A04 this repair method using the requirements in RD-1040(i). The qualification thickness for the test plates and repair grooves shall be in accordance with Table RD-1040-1. e. As shown in Table RD-1040-1, the depth of the repair groove (or full thickness of a joint for a groove weld) in base metal or in weld metal is not limited provided the test material thickness for the welding procedure qualification is at least five times the depth of the repair but need not exceed the thickness of the material to be repaired, provided the required test specimens can be removed. When the thickness of the base metal to be repaired is greater than 2 in. (50 mm), the procedure qualification test material need not exceed 2 in. (50 mm); however, the depth of the groove 108 PART RD — REPAIR/ALTERATION METHODS f. in the test material shall be the greater of 1 in. (25 mm) or the depth of the groove to be repaired. 2. The maximum weld heat input for each layer shall not exceed that used in the procedure qualification test; The test material for the welding procedure qualification shall be of the same material specification (including specification type, grade, class and condition of heat treatment) as the original material specification for the repair. In the event that the notch toughness of the material to be repaired is unknown, evidence from tests of that material or from another acceptable source (see RD-1010) may be used for the base metal notch toughness when qualifying the WPS as required in (g). In the event that the original material specification is obsolete, the test material used should conform as close as possible to the original material used for construction, but in no case shall the material be lower in strength. 3. The minimum preheat temperature for welding shall not be less than that used in the procedure qualification test; g. The organization making the repair shall include, when qualifying its WPS, sufficient tests to determine that the toughness of the weld metal and the heat-affected zone of the base metal in the as-welded condition is adequate at the minimum operating and pressure test temperatures (including start-up and shutdown). When these conditions are met, any original code of construction credit for PWHT may be continued. If for reasons of corrosion resistance, special hardness limits are necessary, such limits shall be included when qualifying the WPS. h. Notch toughness shall be determined and evaluated by Charpy impact tests in accordance with the provisions of the original code of construction. i. The WPS shall include the following additional requirements: 1. The supplemental essential variable of ASME Code, Section IX, paragraph QW-250, shall apply; 109 4. The maximum interpass temperature for welding shall not be greater than that used in the procedure qualification test; 5. The preheat temperature shall be checked to assure that 4 in. (100 mm) of the material or four times the material thickness (whichever is greater) on each side of the weld joint will be maintained at the minimum temperature during welding. When the weld does not penetrate through the full thickness of the material, the minimum preheat temperature need only be maintained at a distance of 4 in. (100 mm) or four times the depth of the repair weld, whichever is greater on each side of the joint; 6. For the welding process in (c) above, use only filler metals which are classified by the filler metal specification with an optional supplemental diffusible-hydrogen designator of H8 or lower. When shielding gases are used with a process, the gas shall exhibit a dew point that is below A04 -60°F (-50°C). Surfaces on which welding will be done shall be maintained in a dry condition during welding and be free of rust, mill scale and hydrogen producing contaminents such as oil, grease and other organic materials. 7. The welding technique shall be a controlled-deposition temper bead or half bead technique. The specific technique or specific combinations of NATIONAL BOARD INSPECTION CODE techniques shall be that used in the procedure qualification test; 8. After completion of welding and without allowing the weldment to cool below the minimum preheat temperature, the temperature of the weldment shall be raised to a temperature of 450°F (230°C) minimum for a minimum period of two hours. This hydrogen bake-out treatment may be omitted provided the electrode used is classified by the filler metal specification with an optional supplemental diffusible-hydrogen designator of H4 (e.g., E7018-H4); and 9. After the finished repair weld has cooled to ambient temperature, the final temper bead reinforcement layer shall be removed substantially flush with the surface of the base material. RD-1050 WELDING METHOD 3 When using this method the following is required: a. This method may be used when the applicable rules of the original code of construction did not require notch toughness testing. d. The welders and welding procedures (WPS) shall be qualified in accordance with the applicable rules of the original code of construction, except that the postweld heat treatment of the test coupon used to qualify the weld procedure shall be omitted. The WPS shall be qualified A04 for this repair method using the requirements in RD-1050(h). The qualification thicknesses for the test plates and repair grooves shall be in accordance with Table RD-1040-1. e. As shown in Table RD-1040-1, the depth of the repair groove (or full thickness of a joint for a groove weld) in base metal or in weld metal is not limited provided the test material thickness for the welding procedure qualification is at least five times the depth of the repair but need not exceed the thickness of the material to be repaired, provided the required test specimens can be removed. When the thickness of the base metal to be repaired is greater than 2 in. (50 mm), the procedure qualification test material need not exceed 2 in. (50 mm); however, the depth of the groove in the test material shall be the greater of 1 in. (25 mm) or the depth of the groove to be repaired. f. b. The materials shall be limited to any P-No. 1 or P-No. 3 material as permitted for welded construction by the applicable rules of the original code of construction. c. The welding shall be limited to the shielded metal-arc welding (SMAW) and gas tungsten-arc welding (GTAW) processes. The test material for the welding procedure qualification shall be of the same P-No. and Group No. as the original material specification for the repair. In the event that the original material specification is obsolete, the test material used should conform to the nominal composition and carbon equivalent (IIW formula) as the original material used for construction, but in no case shall the material be lower in strength. g. If for reasons of corrosion resistance, special hardness limits are necessary, such limits shall be included when qualifying the WPS. 110 PART RD — REPAIR/ALTERATION METHODS h. The WPS shall include the following additional requirements: period of two hours. This hydrogen bake-out treatment may be omitted provided the electrodes used are classified by the filler metal specification with an optional supplemental diffusible-hydrogen designator of H4 (e.g., E7018-H4); and 1. The maximum weld heat input for each layer shall not exceed that used in the procedure qualification test; 2. The minimum preheat temperature for welding shall be 350°F (175°C) and the maximum interpass temperature shall be 450°F (230°C); A04 3. For the welding process in (c) above, use only filler metals which are classified by the filler metal specification with an optional supplemental diffusible-hydrogen designator of H8 or lower. When shielding gases are used with a process, the gas shall exhibit a dew point that is below -60°F (-50°C). Surfaces on which welding will be done shall be maintained in a dry condition during welding and be free of rust, mill scale and hydrogen producing contaminents such as oil, grease and other organic materials. 4. The welding technique shall be a controlled-deposition temper bead or half bead technique. The specific technique or specific combinations of techniques shall be that used in the procedure qualification test; 5. For SMAW the electrode size shall not exceed 1/8 in. (3 mm) and for GTAW the electrode size and the filler metal size shall not exceed 3/32 in. (2.5 mm); 6. For welds made by SMAW, after completion of welding and without allowing the weldment to cool below the minimum preheat temperature, the temperature of the weldment shall be raised to a temperature of 450°F (230°C) minimum for a minimum 7. After the finished repair weld has cooled to ambient temperature, the final temper bead reinforcement layer shall be removed substantially flush with the surface of the base material. RD-1060 WELDING METHOD 4 When using this method the following is required: a. This method is limited to boilers for which the applicable rules of the original code of construction did not require notch toughness testing. b. The materials shall be limited to P-No. 4, Groups 1 and 2 and P-No. 5A steels as permitted for welded construction by the applicable rules of the original code of construction. c. The welding shall be limited to the shielded metal-arc welding (SMAW) fluxcored-arc welding (FCAW) and gas tungsten-arc welding (GTAW) processes using low-hydrogren filler metals clas- A04 sified by the filler metal specification with an optional supplemental diffusable-hydrogen designator of H8 or lower and suitably controlled by maintenance procedures to avoid contamination by hydrogen producing sources. The surface of the metal prepared for welding shall be free of contaminants. d. The welders and welding procedures (WPS) shall be qualified in accordance 111 NATIONAL BOARD INSPECTION CODE with the applicable rules of the original code of construction, except that the postweld heat treatment of the test coupon used to qualify the weld procedure shall be omitted. The WPS shall be qualified for this repair method using the requirements in RD-1060 (h). The qualification thickness for the test plates and repair grooves shall be in accordance with Table RD-1040-1. A04 h. The WPS shall include the following additional requirements: e. As shown in Table RD-1040-1, the depth of the repair groove (or full thickness of a joint for a groove weld) in the base metal or in weld metal is not limited provided the test material thickness for the welding procedure qualification is at least five times the depth of the repair, but need not exceed the thickness of the material to be repaired, provided the required test specimens can be removed. When the thickness of the base metal to be repaired is greater than 2 in. (50 mm), the procedure qualification test material need not exceed 2 in. (50 mm); however, the depth of the groove in the test material shall be the greater of 1 in. (25 mm) or the depth of the groove to be repaired. f. The test material for the welding procedure qualification shall be of the same P-No. and Group No. as the original material specification for the repair. In the event that the original material specification is obsolete, the test material used shall conform to the nominal composition and carbon equivalent (IIW formula) as the original material used for construction, and in no case shall the material be lower in strength. g. If for reasons of corrosion resistance, special hardness limits are necessary, such limits shall be included when qualifying the WPS. 112 1. The minimum preheat temperature for welding shall be 300°F (150°C) for P-No. 4 material and 400°F (205°C) for P-No. 5A material. The preheat temperature shall be checked to assure that 4 in. (100 mm) of the material or four times the material thickness (whichever is greater) on each side of the groove (or full thickness of joint for a groove weld) is maintained at the minimum temperature during welding. The maximum interpass temperature shall not exceed 800°F (425°C). When the weld does not penetrate through the full thickness of the material, the minimum preheat and maximum interpass temperature need only be maintained for 4 in. (100 mm) or four times the depth of the repair weld (whichever is greater) on each side of the joint. 2. The welding technique shall be a controlled-deposition temper bead technique and shall include a buttering layer deposited over the entire groove faces (or fillet leg faces) using a 3/32 in. (2.5 mm) diameter electrode. The buttering layer shall be deposited using stringer beads with an overlap of approximately 50%. The second and remaining layers shall be deposited over the buttering layer using a 3/32 in. (2.5 mm) or 1/8 in. (3 mm) diameter electrode for SMAW, 0.045 in. (1.1 mm) for FCAW, or 1/16 in. (1.5 mm) or 3/32 in. (2.5 mm) for GTAW filler metal. The second and remaining layers shall not contact the base material and shall be deposited using stringer beads. After the groove is filled (or fillet size is achieved), a 3/32 in. (2.5 mm) or 1/8 in. (3 mm) thick reinforcement layer PART RD — REPAIR/ALTERATION METHODS TABLE RD-1040-1 — Welding Methods as Alternatives to Postweld Heat Treatment Qualification Thicknesses for Test Plates and Repair Grooves BASE METAL THICKNESS REPAIR GROOVE DEPTH PQR GROOVE DEPTH Note (2) THICKNESS QUALIFIED Note (1) < 2” (50 mm) < 1” (25 mm) 5 times the repair cavity depth, but need not exceed the thickness of the base metal to be repaired. < 1” (25 mm) See PQR test material thickness column and ≤ PQR groove depth. ≤ 2” (50 mm) > 1” (25 mm) Thickness of the base metal to be repaired. > 1” (25 mm) ≤ PQR test material thickness and ≤ PQR groove depth. > 2” (50 mm) 1” (25 mm) 2” (50 mm) 1” (25 mm) All base metal thickness and ≤ 1” (25 mm) repair groove depth. > 2” (50 mm) > 1” (25 mm) 2” (50 mm) > 1” (25 mm) All base metal thickness and ≤ PQR groove depth. PQR TEST MATERIAL THICKNESS Note 1. Repair groove depth is limited to the maximum depth qualified. Note 2. The depth of the groove used for procedure qualification must be deep enough to remove test specimens. shall be deposited to temper the prior weld layer. This temper layer shall be deposited to within 1/8 in. (3 mm) of the toe of the weld, but shall not contact the base metal. A04 3. After completion of welding and without allowing the weldment to cool below the minimum preheat temperature, the temperature of the weldment shall be raised to a temperature of 450°F (230°C) minimum for a minimum period of two hours. This hydrogen bake-out treatment may be omitted provided the filler metal used is classified by the filler metal specification with an optional supplemental diffusable-hydrogen designator of H4 (e.g., E7018-H4). 4. After the finished repair weld has cooled to ambient temperature, the final temper bead reinforcement layer shall be removed substantially flush with the surface of the base metal (and for a fillet weld to the required size and suitable contour of the toes). RD-1070 WELDING METHOD 5 When using this method the following is required: a. This method may be used when the applicable rules of the original code of construction for which postweld heat treatment for one material joined to another material for which postweld heat treatment may be 113 A04 NATIONAL BOARD INSPECTION CODE inadvisable, such as carbon or low-alloy steel joined to austenitic stainless steel or to nickel or nickel-based alloys. b. The materials shall be limited to those materials conforming to any of the following ASME designations: P-No. 1, Groups 1, 2, and 3, P-No. 3, Groups 1, 2, and 3, P-No. 4, P-No. 5A, P-No. 9A, P-No. 10A, P-No. 10B, P-No. 10C, P-No. 11A, or P-No. 11B joined to either P-No. 8, P-No. 41, P-No. 42, P-No. 43, P-No. 44, P-No. 45, P-No. 46, or P-No. 47 as permitted for welded construction by the applicable rules of the original code of construction. c. The welding shall be limited to the shielded metal-arc welding (SMAW), fluxcored-arc welding (FCAW), gas metal-arc welding (GMAW), and gas tungsten-arc welding (GTAW) processes. The surface of the metal prepared for welding shall be free of contaminants. It is cautioned to determine if the dissimilar metal joint will be exposed to elevated temperature service since significant differences in coefficient of thermal expansion of dissimilar metal-welded joints may result in excessive differences in relative deformation and thermal fatigue at the joint. The electrodes/filler metals for dissimilar metal welded joint shall be either of those conforming to the ASME designations A-No. 8 or F-No. 43 as applicable. It is cautioned that using austenitic stainless steel electrodes/filler metals for joining P-No. 8 materials to carbon or low-alloy steels for weld joints exposed to service temperatures greater than 800°F (425°C) will exhibit reduced creep life along the fusion zone of the ferritic material due to carbon diffusion. d. The welders and welding procedures (WPS) shall be qualified in accordance with the applicable rules of the original code of construction, except that the postweld heat treatment of the test coupon used to qualifty the weld procedure shall be omitted in accordance with the following paragraphs (e) through (h), as applicable. e. Qualification of welding procedures (WPS) for joining P-No. 1 Groups 1, 2, and 3, P-No. 3, Groups 1, 2 (excluding MnMo steels in Group 2) ferritic materials to either P-No. 8, P-No. 41, P-No. 42, P-No. 43, P-No. 44, P-No. 45, P-No. 46 or P-No. 47 materials shall be in accordance with RD-1030 Welding Method 1 if the original code of construction did not require notch toughness testing. f. Qualification of welding procedures (WPS) for joining ASME P-No. 1, Groups 1, 2, and 3, P-No. 3 Groups 1, 2, and 3, PNo. 4, P-No. 5A, P-No. 9A, P-No. 10A, PNo. 10B, P-No. 10C, P-No. 11A, P-No. 11B ferritic materials to either P-No. 8, P-No. 41, P-No. 42, P-No. 43, P-No. 44, P-No. 45, P-No. 46 or P-No. 47 materials shall be in accordance with RD-1040 Welding Method 2 if the original code of construction required notch toughness testing or when the original code of construction did not require notch toughness testing provided the adequacy of the heat affected zone of the ferritic material in the as-welded condition at operating and pressure test conditions has been verified. g. Qualification of welding procedures (WPS) for joining any P-No. 1 or P-No. 3 materials to P-No. 8, P-No. 41, P-No. 42, P-No. 43, P-No. 44, P-No. 45, P-No. 46 or P-No. 47 materials shall be in accordance with RD-1050 Welding Method 3 if the original code of construction did not require notch toughness testing and the 114 PART RD — REPAIR/ALTERATION METHODS welding is limited to the shielded metalarc welding (SMAW) and the gas-tungsten-arc welding (GTAW) processes. h. Qualification of welding procedures (WPS) for joining P-No. 4 and P-No. 5A materials to either P-No. 8, P-No. 41, P-No. 42, P-No. 43, P-No. 44, P-No. 45, P-No. 46 or P-No. 47 materials shall be in accordance with RD-1060 Welding Method 4 if the original code of construction did not require notch toughness testing. i. The requirements of RD-1040(i)(6) and (i)(8), RD-1050 (h)(3) and RD-1060(c) and (h)(3) for low hydrogen electrodes/filler metals and for a hydrogen bake-out treatment may be omitted. RD-1100 ALTERNATIVE LOCAL POST WELD HEAT TREATMENT METHOD When it is impractical or detrimental to post weld heat treat the entire item or an entire band around the item, the following local (e.g., bulls eye) post weld heat treatment method may be performed on spherical or cylindrical pressure retaining items using the time and temperature parameters in the original code of construction and in accordance with a written procedure. a. Heat a local area around the nozzle, welded attachment or repair area in such a manner that the area is brought up uniformly to the required temperature. The application of local post weld heat treatment should be performed with controlled heating methods such as induction or electric resistance heaters with thermocouples. The soak band, which is the band required to be heated to the minimum PWHT temperature, shall be a circle (e.g., bulls eye method) that extends beyond the entire nozzle, attachment weld and repair area in all directions by a minimum of the thickness of the shell, t or 2” (50 mm), whichever is less. b. The temperature gradient extending outside the bulls eye post weld heat treatment band applied to repair welds or attachment welds shall be kept as low as possible in all directions to avoid harmful temperature gradients adjacent to nozzles or geometric discontinuities. c. For bulls eye post weld heat treatment of nozzle welds, repair welds and external attachment welds on smooth spherical shells, heads and cylindrical shells the thermal gradients outside the circumferential heat band should not exceed 250°F (120°C) per foot (0.3 m). d. The term t, or definition of thickness for calculating the holding time, for local post weld heat treatment shall be the nominal thickness of either a full penetration weld, the groove weld depth of a partial penetration repair weld or if a fillet weld is used in combination with a groove weld the nominal thickness is the depth of the groove or the throat dimensions, whichever is greater. RD-2000 REPAIR METHODS RD-2010 SCOPE A repair of a defect, such as a crack in a welded joint or base material, shall not be made until the defect has been removed. A suitable nondestructive examination method such as magnetic particle (MT) or liquid penetrant (PT) may be necessary to assure complete 115 NATIONAL BOARD INSPECTION CODE removal of the defect. If the defect penetrates the full thickness of the material, the repair shall be made with a complete penetration weld such as a double butt weld or a single butt weld with or without backing. Where cirA04 cumstances indicate that the defect is likely to recur, consideration should be given to removing the defective area and installing a flush patch or taking other acceptable, corrective measures. A repair of a bulge or blister shall be made if a bulge or blister will affect the pressure-retaining capability of the plate or tube or when evidence of leakage is noted. RD-2020 DEFECT REPAIRS Unstayed Boiler Furnace Cracks Cracks at the knuckle or at the turn of the flange of the furnace opening require immediate replacement of the affected area or specific approval of repairs by the jurisdiction. See Figure RD-2020-a. Rivet or Staybolt Hole Cracks Cracks radiating from rivet or staybolt holes may be repaired if the plate is not seriously damaged. If the plate is seriously damaged, it shall be replaced. For suggested methods of repair. See Figure RD-2020-b. Minor Defects Minor cracks, isolated pits and small plate imperfections should be examined to determine the extent of the defect and whether repair by welding is required. Prior to repair by welding, the defects shall be removed to sound metal. Liquid penetrant or magnetic particle examination may be used before or after welding. Defective Bolting Defective bolting material shall not be repaired but shall be replaced with suitable material which meets the specifications of the original code of construction. A bulge on a water tube shall be investigated A04 to determine the cause and extent of damage to the tube prior to repair. If the bulge has resulted in metallurgical changes to the original tube material as determined by field metallography, installation of a new length of tubing or tube patch (RD-2060) is required. If the bulge has cracks as determined by NDE, installation of a new length of tubing or a tube patch is required. If the bulge does not exhibit cracks and has not resulted in metallurgical changes to the original tube material, a mechanical repair may be considered subject to the concurrence of the inspector or jurisdiction. A bulge on a plate shall be investigated to de- A04 termine the cause and extent of damage to the plate prior to repair. If the bulge has resulted in metallurgical changes to the original plate material as determined by field metallography, installation of a flush patch (RD-2060) is required. If the plate has cracks as determined by NDE, installation of a flush patch is required. If the bulge does not exhibit cracks and has not resulted in metallurgical changes to the original plate material, a mechanical repair may be considered, subject to the concurrence of the inspector or jurisdiction. A blister may be caused by a defect in the metal such as lamination where one side ex- A04 posed to the fire overheats but the other side retains its strength due to the cooling effect of the water. After the blistered material has been removed, the remaining wall thickness shall be determined by ultrasonic thickness testing. A surface examination using liquid penetrant testing or magnetic particle testing shall be made to assure the remaining material contains no defects. If the remaining wall thickness is adequate, in the judgement of the inspector, the area may be repaired by welding as covered in RD-2030, Wasted Areas. If the remaining wall thickness is not adequate, 116 PART RD — REPAIR/ALTERATION METHODS a plate will require a flush patch (RD-2060) and a tube will require a new length of tube or tube patch (RD-2060). RD-2030 WASTED AREAS Shells, Drums, Headers Wasted areas in stayed and unstayed shells, drums and headers may be built up by welding provided that in the judgement of the Inspector the strength of the structure has not been impaired. Where extensive weld buildup is employed, the Inspector may require an appropriate method of NDE for the completed surface of the repair. For suggested methods of building up wasted areas by welding. See Figure RD-2030-a. Access Opening Wasted areas around access openings may be built up by welding or they may be repaired as described in Figure RD-2030-b. Flanges Wasted flange faces may be cleaned thoroughly and built up with weld metal. They should be machined in place if possible to a thickness not less than that of the original flange or that required by calculations in accordance with the provisions of the original code of construction. Wasted flanges may also be remachined in place without building up with weld metal provided that metal removed in the process does not reduce the thickness of the flange to a measurement below that calculated above. Flanges which leak because of warpage or distortion and which cannot be remachined shall be replaced with new flanges which have at least the dimensions conforming to the original code of construction. Tubes Wasted areas on tubes may be repaired by welding provided that in the judgement of the Inspector the strength of the tube has not been impaired. Where deemed necessary, competent technical advice should be obtained from the manufacturer or from another qualified source. This may be necessary when considering such items as size limitations of repaired areas, minimum tube thickness to be repaired, tube environment, location of the tube in the boiler and other similar conditions. RD-2040 SEAL WELDING Seal Welding of Tubes Tubes may be seal welded provided the ends of the tubes have sufficient wall thickness to prevent burn through and the requirements of the original code of construction are satisfied. See Figure RD-2040-a. Seal Welding of Riveted Joints Edges of buttstraps, plate laps and nozzles, or of connections attached by riveting may be restored to original dimensions by welding. Seal welding of riveted joints, buttstraps or rivets shall require the approval of the jurisdiction. If seal welding is approved, suggested methods and precautions are shown in Figure RD-2040-b. RD-2050 RE-ENDING OR PIECING PIPES OR TUBES Re-ending or piecing pipes or tubes is permitted provided the thickness of the remaining pipe or tube is not less than 90% of that required by the original code of construction. RD-2060 PATCHES Flush Patches The weld around a flush patch shall be a full penetration weld and the accessible surfaces shall be ground flush where required 117 NATIONAL BOARD INSPECTION CODE FIGURE RD-2020-a — UNSTAYED BOILER FURNACES Cracks at the knuckle or at the turn of the flange of the furnace opening require immediate replacement of the affected area. If repairs are attempted, specific approval of the jurisdiction is required. FIGURE RD-2020-b — RIVET AND STAYBOLT HOLE CRACKS Cracks radiating from rivet or staybolt holes may be repaired if the plate is not seriously damaged. If the plate is seriously damaged, it shall be replaced. A suggested repair method is described below: a. Prior to welding, the rivets or staybolts from which the cracks extend and the adjacent rivets (or staybolts if appropriate) should be removed. FIRE CRACKS AT GIRTH SEAMS CIRCUMFERENTIAL CRACKS AT GIRTH SEAMS b. In riveted joints, tack bolts should be placed in alternate holes to hold the plate laps firmly. c. The cracks should then be prepared for welding by chipping, grinding or gouging. d. In riveted joints, cracks which extend past the inner edge of the plate lap should be welded from both sides. e. Rivet holes should be reamed before new rivets are driven. CRACKS IN STAYED PLATES 118 PART RD — REPAIR/ALTERATION METHODS f. Threaded staybolt holes should be retapped and new staybolts properly driven and headed. FIGURE RD-2030-a — WELD BUILDUP OF WASTED AREA Rivet and Staybolts a. Prior to welding, the rivets or staybolts in the wasted area should be removed. FIRE CRACKS AT DOOR OPENINGS b. Threaded staybolt holes should be retapped after welding. c. Rivet holes should be reamed after welding. d. Welding should not cover rivet or staybolt heads. Tubesheet a. Prior to welding, the tubes in the wasted area should be removed. rivet and staybolt b. After welding, the tube holes may be reamed before new tubes are installed. Wasted areas in stayed and unstayed surfaces may be repaired by weld build-up, provided that in the judgment of the Inspector the strength of the structure will not be impaired. Where extensive weld buildup is employed, the Inspector may require an appropriate method of NDE for the complete surface of the repair. TUBESHEET 119 NATIONAL BOARD INSPECTION CODE FIGURE RD-2030-b — REPAIRS FOR ACCESS OPENINGS A badly wasted manhole flange may be removed and replaced with a ringtype frame as shown at right. The requirements for flush patches shall be met. A full penetration weld is required. May be either double or welded from one side with or without a backing ring. �� A badly wasted area around a handhole opening may be repaired by adding a ring, as shown at right, on the inside of the object. FIGURE RD-2040-a — TYPICAL EXAMPLES OF SEAL WELDING TUBES Tubes may be seal welded provided the ends of the tubes have sufficient wall thickness to prevent burnthrough. Seal welding shall be applied with a maximum of three light layers in lieu of one or two heavy layers. Seal welding shall not be considered a strength weld. In watertube boilers, tubes may be seal welded on the inside or outside of the tubesheet. 120 PART RD — REPAIR/ALTERATION METHODS FIGURE RD-2040-b — SEAL WELDING OF RIVETED JOINTS Seal welding of riveted joints requires the approval of the jurisdiction. Seal welding shall not be considered a strength weld. Prior to welding, the area should be examined by an appropriate method of NDE to assure that there are no cracks radiating from the rivet holes. If necessary, the rivets should be removed to assure complete examination of the area. Seal welding should not be performed if cracks are present in riveted areas. FIGURE RD-2060-a — FLUSH PATCHES Before installing a flush patch, the defective material should be removed until sound material is reached. The patch should be rolled or pressed to the proper shape or curvature. The edges should align without overlap. �� TYPICAL RIVET JOINT SHOWING SEAL WELD FLUSH PATCHES IN UNSTAYED AREAS In stayed areas, the weld seams should come between staybolt rows or riveted seams. Patches should be made from a material that is at least equal in quality and thickness to the original material. Patches may be of any shape or size. If the patch is rectangular, an adequate radius should be provided at the corners. Square corners should be FLUSH PATCHES IN STAYED AREAS avoided. 121 NATIONAL BOARD INSPECTION CODE FIGURE RD-2060-b — TUBE WINDOW PATCHING METHOD It may be necessary to weld a flush patch on a tube since, in some situations, accessibility around the complete circumference of the tube is restricted. Listed below are the suggested methods for making window patches: a. The patch should be made from tube material of the same type, diameter and thickness as the one being repaired. b. Fit-up of the patch is important to weld integrity. The root opening should be uniform around the patch. FRONT AND SIDE VIEW OF TUBE c. The gas tungsten-arc welding process should be used for the initial pass on the inside of the tube and for the initial pass joining the patch to the tube. �� d. The balance of the weld may be completed by any appropriate welding process. �� SIDE VIEW SHOWING PATCH FIT AND WELDING 122 PART RD — REPAIR/ALTERATION METHODS by the applicable original code of construction. Examples of flush welded patches are shown in Figure RD-2060-a. The welds shall be subjected to the non-destructive examination method used in the original code of construction or an alternative acceptable to the Inspector. Tube Patches In some situations it is necessary to weld a flush patch on a tube, such as when replacing tube sections and accessibility around the complete circumference of the tube is restricted or when it is necessary to repair a small bulge. This is referred to as a window patch. Suggested methods for window patches are shown in Figure RD-2060-b. RD-2070 STAYS Threaded stays may be replaced by welded-in stays provided that, in the judgement of the Inspector, the material adjacent to the staybolt has not been materially weakened by deterioration or wasting away. All requirements of the original code of construction governing welded-in stays shall be met. RD-3000 ALTERATIONS BASED ON ALLOWABLE STRESS VALUES RD-3010 RE-RATING The following requirements shall apply for re-rating a pressure retaining item by using a later edition/addendum of the original code of construction which permits higher allowable stress values for the material than was used in the original construction. a. The “R” Certificate Holder shall verify, by calculations and other means, that the rerated item can be satisfactorily operated at the new service condition (e.g., stiffness, buckling, external mechanical loadings, etc.). b. The pressure-retaining item shall not be used in lethal service. c. The pressure-retaining item shall not be used in high-cycle operation or fatigue service (i.e., loadings other than primary membrane stress are controlling design considerations). d. The pressure-retaining item shall have been constructed to the 1968 Edition or later edition/addenda of the original code of construction. e. The pressure-retaining item shall be shown to comply with all relevant requirements of the edition/addenda of the code of construction which permits the higher allowable stress values (e.g., reinforcement, toughness, examination, pressure testing, etc.). f. The pressure-retaining item shall have a satisfactory operating history and current inspection of the pressure retaining item shall verify the item exhibits no unrepaired damage (e.g., cracks, corrosion, erosion, etc.). g. The re-rating shall be acceptable to the Inspector and, where required, the jurisdiction. h. All other requirements of Part RC shall be met. i. 123 Use of this paragraph shall be documented in the Remarks Section of Form R-2. NATIONAL BOARD INSPECTION CODE RD-3020 f. MINIMUM WALL THICKNESS The following requirements shall apply for recalculating a new minimum wall thickness for a pressure-retaining item by using a later edition/addendum of the original code of construction which permits higher allowable stress values for the material than was used in the original construction. a. The “R” Certificate Holder shall verify, by calculations and other means, that the affected portions of the pressure-retaining item can be satisfactorily operated (e.g., stiffness, buckling, external mechanical loadings, etc.). b. The pressure-retaining item shall not be used in lethal service. The pressure-retaining item shall have a satisfactory operating history and current inspection of the pressure-retaining item shall verify the item exhibits no unrepaired damage (e.g., cracks, etc.). Areas of corrosion or erosion may be left in place provided the remaining wall thickness is greater than the new minimum thickness. g. The design shall be acceptable to the Inspector and, where required the jurisdiction. h. All other requirements of Part RC shall be met. i. c. The pressure-retaining item shall not be used in high-cycle operation or fatigue service (i.e., loadings other than primary membrane stress are controlling design considerations). d. The pressure-retaining item shall have been constructed to the 1968 Edition or later edition/addenda of the original code of construction. e. The pressure-retaining item shall be shown to comply with all relevant requirements of the edition/addenda of the code of construction which permits the higher allowable stress values (e.g., reinforcement, toughness, examination, pressure testing, etc.). 124 Use of this paragraph shall be documented in the Remarks Section of Form R-2. Repairs of Pressure Relief Valves Part RE 125 NATIONAL BOARD INSPECTION CODE PART RE — REPAIRS OF PRESSURE RELIEF VALVES TABLE OF CONTENTS RE-1000 RE-1010 RE-1020 RE-1030 RE-1040 RE-1050 RE-1060 RE-1070 General ............................................................................................................... 127 Scope ................................................................................................................... 127 Definition of Repair .......................................................................................... 127 Accreditation ......................................................................................................128 Materials .............................................................................................................128 Replacement Parts .............................................................................................128 Nameplates .........................................................................................................128 Field Repair ........................................................................................................130 RE-1000 RE-1110 RE-1120 RE-1130 RE-1140 RE-1150 RE-1160 Welding for Pressure Relief Valves ................................................................ 131 Welding Procedure Specifications .................................................................. 131 Standard Welding Procedure Specifications ..................................................131 Performance Qualification ...............................................................................131 Welding Records ................................................................................................131 Welders’ Identification ......................................................................................131 Welders’ Continuity ..........................................................................................132 RE-1200 RE-1210 RE-1220 Heat Treatment...................................................................................................132 Preheating .......................................................................................................... 132 Postweld Heat Treatment .................................................................................132 RE-2000 RE-2010 RE-2020 RE-2030 Performance Testing and Testing Equipment................................................132 Test Medium and Testing Equipment.............................................................132 Owner-User Section VIII Steam Testing .........................................................133 Lift Assist Testing...............................................................................................133 RE-3000 RE-3010 RE-3020 RE-3030 RE-3040 Training and Qualification of Personnel ........................................................134 General ................................................................................................................134 Contents of Training Program .........................................................................134 Qualification of Personnel ................................................................................134 Annual Review of Qualification ......................................................................134 126 PART RE — REPAIRS OF PRESSURE RELIEF VALVES RE-1000 GENERAL REQUIREMENTS RE-1010 SCOPE This part provides general requirements that apply to repairs to pressure relief valves. Repairs may be required because of defects found during periodic inspections because testing has identified that valve performance does not meet the original Code of Construction requirements, failure during operation, or for routine preventative maintenance. RE-1020 DEFINITION OF REPAIR Repair of a pressure relief valve is considered to be the disassembly, replacement, remachining, or cleaning of any critical part, lapping of a seat and disc, reassembly, adjustment, testing, or any other operation that may affect the flow passage, capacity, function or pressure-retaining integrity. Conversions, changes or adjustments affecting critical parts are also considered repairs. The scope of conversions may include changes in service fluid and changes such as bellows, soft seats and other changes that may affect type/model number provided such changes are recorded on the document required by RA-2255(i) and the repair nameplate. See RE-1060. The scope of repair activities shall not include changes in ASME Code status. When a repair is being performed under the administrative requirements of Part RA-2200, a repair shall consist of the following operations as a minimum: a. Complete disassembly, cleaning and inspection of all parts, repair or replacement of parts found to be defective, reassembly, testing as required by RE-2000, sealing and application of a repair nameplate. When completed, the valve’s condition and performance shall be equivalent to the standards for new valves. b. The administrative requirements of RA-2200 apply only to valves which are stamped with an ASME “V”, “UV”, or “NV” Code symbol or marked with an ASME “HV” symbol and have been capacity certified on the applicable fluid by the National Board. RE-1021 CONSTRUCTION STANDARDS The applicable standard for new valves to be used for reference during repairs is the ASME Code. ASME Code Cases shall be used for repairs when they were used in the original construction of the valve. ASME Code Cases may be used when they have been accepted for use by revision or interpretation by the NBIC Committee. The Code Case number shall be noted on the repair document specified in RA-2255(i)(1), and when required by the Code Case, stamped on the repair nameplate. The applicable jurisdiction shall be consulted for any unique requirements it may have established. RE-1022 INITIAL ADJUSTMENTS TO PRESSURE RELIEF VALVES The initial installation testing and adjustments of a new pressure relief valve on a boiler or pressure vessel are not considered a repair if made by the manufacturer or assembler of the valve. 127 NATIONAL BOARD INSPECTION CODE RE-1023 JURISDICTIONAL AUTHORIZATION TO ADJUST PRESSURE RELIEF VALVES RE-1050 The jurisdiction may authorize properly trained and qualified employees of boiler or pressure vessel owners-users or their designees to restore required set pressure and/or performance of pressure relief valves. All external adjustments shall be resealed with a seal identifying the responsible organization and a metal tag that identifies the organization and the date of the adjustment shall be installed (See RE-1063 for marking requirements and Appendix J). RE-1024 DEFINITIONS Unless otherwise specified in these rules and procedures, the definitions relating to pressure relief devices in Section 2 of ANSI/ ASME PTC-25-2001 shall apply. RE-1030 Organizations performing repairs shall be accredited as described in Part RA-2200, as appropriate for the scope of work to be performed. RE-1040 All critical parts shall be fabricated by the valve manufacturer or to his specifications. Critical parts are those that may affect the valve flow passage, capacity, function or pressure-retaining integrity. All critical parts not fabricated by the valve manufacturer shall be received with material test certification for the material used to fabricate the part. Parts fabricated by the valve manufacturer do not require material test certification if they have the manufacturer’s identification on the part or are accompanied by the manufacturer’s identification label or tag. Material for bolting shall meet the manufacturer’s specification, but does not require material test certification if marked as required by the material specification. RE-1060 ACCREDITATION MATERIALS The materials used in making repairs shall conform to the requirements of the original code of construction. The “VR” Certificate Holder is responsible for verifying identification of existing materials from original data, drawings, or unit records and identification of the materials to be installed. REPLACEMENT PARTS NAMEPLATES Proper marking and identification of tested or repaired valves is critical to ensuring a valves acceptance during subsequent inspections, and also provide for traceability and identification of any changes made to the valve. All operations which require the valve’s seals to be replaced shall be identified by a nameplate as described in RE-1061 or RE-1063. RE-1061 REPAIR NAMEPLATE When a pressure relief valve is repaired, a metal repair nameplate stamped with the information required by RE-106 shall be securely attached to the valve. If not mounted A04 directly on the valve, the nameplate shall be securely attached so as not to interfere with valve operation and sealed in accordance with RA-2255(k). 128 PART RE — REPAIRS OF PRESSURE RELIEF VALVES As a minimum, the information on the valve repair nameplate (see Appendix 2, Figure 21000-e) shall include: marked out but left legible. The new capacity shall be based on that for which the valve was originally certified. a. The name of the repair organization preceded by the words “repaired by”; If the service fluid is changed, the capacity, including units, on the original nameplate or stamping shall be marked out but left legible. The new capacity shall be based on that for which the valve was originally certified, or if a conversion has been made, as described in RE-1020 on the capacity certification for the valve as converted. b. The “VR” repair symbol stamp and the “VR” Certificate Number; c. Unique identifier (e.g., repair serial number, shop order number, etc.); d. Date of repair; If the type/model number is changed, the type/model number on the original nameplate shall be marked out but left legible. e. Set pressure; f. Capacity and capacity units (if changed from original nameplate due to set pressure or service fluid change); and g. Type/model number (if changed from original nameplate by a conversion, see RE-1020). h. When an adjustment is made to correct for service conditions of superimposed back pressure and/or temperature or the differential between popping pressure between steam and air (See RE-2200), the information on the valve repair nameplate shall include the: 1. Cold Differential Test Pressure (CDTP), and 2. Superimposed Back Pressure (BP) (only when applicable) RE-1062 CHANGES TO ORIGINAL PRESSURE RELIEF VALVE NAMEPLATE INFORMATION If the set pressure is changed, the set pressure, capacity and blowdown, if applicable, on the original nameplate or stamping shall be If the blowdown is changed, the blowdown on the original nameplate or stamping shall be marked out but left legible. The new blowdown may be based on the current ASME Code requirements. RE-1063 TEST ONLY NAMEPLATE Where a valve has been tested and adjusted as permitted by RE-1023 but not otherwise repaired, a “Test Only” nameplate shall be applied which contains the following information: a. Name of responsible organization, b. Date of test, c. Set Pressure, d. An identification such as “Test Only.” A “test only” nameplate is also recommended when periodic testing has been performed, even when no adjustments have been made, for the purpose of identifying the date the valve was tested. 129 NATIONAL BOARD INSPECTION CODE RE-1064 ILLEGIBLE OR REPLACEMENT OF MISSING NAMEPLATES RE-1070 Illegible Nameplates When the information on the original manufacturer’s or assembler’s nameplate or stamping is illegible, the nameplate or stamping will be augmented or replaced by a nameplate furnished by the “VR” stamp holder stamped “duplicate”. It shall contain all information that originally appeared on the nameplate or valve, as required by the applicable section of the ASME Code, except the “V”, “HV” or “UV” symbol and the National Board mark. The repair organization’s nameplate, with the “VR” stamp and other required data specified in RE-1061, will make the repairer responsible to the owner and the jurisdiction that the information on the duplicate nameplate is correct. Missing Nameplates When the original valve nameplate is missing, the repair organization is not authorized to perform repairs to the valve under the “VR” program, unless positive identification can be made to that specific valve and verification that the valve was originally stamped with an ASME “V” or “UV” symbol or marked with an ASME “HV” symbol. Valves that can be positively identified will be equipped with a duplicate nameplate, as described in RE-1064, in addition to the repairer’s “VR” stamped nameplate. The repairer’s responsibilities for accurate data, as defined in RE-1064 (Illegible Nameplates), shall apply. Marking of Original Code Stamp When a duplicate nameplate is affixed to a valve, as required by RE-1064, it shall be marked “Sec. I”, “Sec. IV” or “Sec. VIII”, as applicable, to indicate the original ASME Code stamping. FIELD REPAIR Repair organizations may obtain a “VR” Certificate of Authorization for field repair, either as an extension to their in-shop/plant scope or as a field-only scope, provided that: a. Qualified technicians in the employ of the certificate holder perform such repairs; b. An acceptable quality system covering field repairs, including field audits, is maintained; c. All functions affecting the quality of the repaired valves are supervised from the address of record where the “VR” certification is issued. RE-1071 AUDIT REQUIREMENTS Upon issuance of a certificate of authorization, provided field repairs are performed, annual audits of the work carried out in the field shall be performed to ensure that the requirements of the certificate holder’s quality system are met. The audit shall include, but not be limited to, performance testing, in accordance with RE-2000, of valve(s) that were repaired in the field. The audits shall be documented. RE-1072 USE OF OWNER-USER PERSONNEL For the repair of pressure relief valves at an owner-user’s facility for the owner-user’s own use, the “VR” Certificate Holder may utilize owner-user personnel to assist certificate holder technician(s) in the performance of repairs provided: a. The use of such personnel is addressed in the “VR” Certificate Holder’s quality system; 130 PART RE — REPAIRS OF PRESSURE RELIEF VALVES b. The owner-user personnel are trained and qualified in accordance with RE-3000; c. Owner-user personnel work under direct supervision and control of the “VR” Certificate Holder’s technician(s) during any stage of the repair when they are utilized; d. The “VR” Certificate Holder shall have the authority to assign and remove owneruser personnel at its own discretion; e. The names of the owner-user personnel utilized are recorded on the document required by RA-2255(i). RE-1100 WELDING FOR PRESSURE RELIEF VALVES Welding shall be performed in accordance with the requirements of the original code of construction used for the pressure relief valve. Cast iron and carbon or alloy steel having a carbon content of more than 0.35%, shall not be welded. Defects in pressure relief valve parts such as cracks, pits or corrosion that will be repaired by welding shall be completely removed before the weld repair of the part is performed. Removal of the defect shall be verified by suitable NDE as required. Consideration shall be given to the condition of the existing material, especially in the weld preparation area. RE-1110 WELDING PROCEDURE SPECIFICATIONS Welding shall be performed in accordance with Welding Procedure Specifications (WPS) qualified in accordance with the original code of construction. When this is not possible or practicable, the WPS may be qualified in accordance with Section IX of the ASME Code. RE-1120 STANDARD WELDING PROCEDURE SPECIFICATIONS A “VR” Certificate Holder may use one or more applicable Standard Welding Procedure Specifications shown in Appendix A. RE-1130 PERFORMANCE QUALIFICATION Welders or welding operators shall be qualified for the welding processes that are used. Such qualification shall be in accordance with the requirements of the original code of construction or Section IX of the ASME Code. RE-1140 WELDING RECORDS The “VR” Certificate Holder shall maintain a record of the results obtained in welding procedure qualifications, except for those qualifications for which the provisions of RE-1120 are used, and of the results obtained in welding performance qualifications. These records shall be certified by the “VR” Certificate Holder and shall be available to the National Board. RE-1150 WELDERS’ IDENTIFICATION The “VR” Certificate Holder shall establish a system for the assignment of a unique identification mark to each welder/welding operator qualified in accordance with the requirements of the NBIC. The “VR” Certificate Holder shall also establish a written procedure whereby all welded joints can be identified as to the 131 NATIONAL BOARD INSPECTION CODE welder or welding operator who made them. This procedure shall use one or more of the following methods and shall be described in the quality control system written description. The welder’s or welding operator’s identification mark may be stamped (low stress stamp) adjacent to all welded joints made by the individual or, in lieu of stamping, the “VR” Certificate Holder may keep a record of welded joints and the welders or welding operators used in making the joints. RE-1220 RE-1160 Each pressure relief valve to which the “VR” repair symbol stamp is to be applied shall be subjected to the following tests by the repair certificate holder. WELDERS’ CONTINUITY The performance qualification of a welder or welding operator shall be affected when one of the following conditions occur: a. When the welder or welding operator has not welded using a specific process during a period of six (6) months or more, their qualifications for that process shall expire. b. When there is specific reason to question their ability to make welds that meet the specification, the qualification which supports the welding that is being performed shall be revoked. All other qualifications not questioned remain in effect. RE-1200 HEAT TREATMENT RE-1210 PREHEATING POSTWELD HEAT TREATMENT Postweld heat treatment shall be performed as required by the original code of construction in accordance with a written procedure. The procedure shall contain the parameters for postweld heat treatment. RE-2000 RE-2010 PERFORMANCE TESTING AND TESTING EQUIPMENT TEST MEDIUM AND TESTING EQUIPMENT Valves marked for steam service, or having special internal parts for steam service, shall be tested on steam. Valves marked for air, gas or vapor service shall be tested with air or gas. Valves marked for liquid service shall be tested with water or other suitable liquid. Section IV hot water valves shall be tested on water, steam or air. a. Each valve shall be tested to demonstrate the following: Preheating may be employed during welding to assist in completion of the welded joint (Appendix B). The need for and the temperature of preheat are dependent on a number of factors, such as chemical analysis, degree of restraint of the items being joined, material thickness, and mechanical properties. The welding procedure specification for the material being welded shall specify the preheat temperature requirements. 132 1. Set pressure (as defined by the valve manufacturer and as listed in NB-18); 2. Response to blowdown, when required by the original Code of Construction; 3. Seat tightness; 4. For valve designed to discharge to a closed system, the tightness of the secondary pressure zone shall be tested as required by the original Code of Construction. PART RE — REPAIRS OF PRESSURE RELIEF VALVES b. The equipment used for the performance testing prescribed by RE-2010 shall meet the following requirements: contents of the document required in RE-2010(b)(2), the certificate holder shall requalify the performance test equipment in accordance with RE2010(b)(2). If the equipment changed was used to satisfy the requirements of verification testing, the certificate holder shall notify the National Board and additional verification testing, in accordance with RA-2225, may be required. 1. The performance testing equipment shall include a pressure vessel of adequate volume and pressure source capacity to ensure compliance with RE-2010(a)(1). 2. Prior to use, all performance testing equipment shall be qualified by the certificate holder to ensure that the equipment and testing procedures will provide accurate results when used within the ranges established for that equipment. This qualification may be accomplished by bench mark testing, comparisons to equipment used for verification testing (RA-2225) or comparisons to field performance. This qualification shall be documented and provisions made to retain such documentation for a period of at least five years after the testing equipment is retired. Documentation of this qualification shall include but not be limited to: a. Schematic of the performance test equipment; b. Size and pressure ranges of valves to be tested; c. Dimensions of test vessels; d. Accuracy of pressure measuring equipment; e. Size and design type of valves used to control flow; and f. Method of qualifying. 3. Prior to the implementation of any addition or modification to the testing equipment which would alter the RE-2020 OWNER-USER SECTION VIII STEAM TESTING When ASME Section VIII valves are repaired by the owner for the owner’s own use, valves for steam service may be tested on air for set pressure and, if possible, blowdown adjustment provided manufacturer’s corrections for differential in set pressure between steam and air are applied to the set pressure. RE-2030 LIFT ASSIST TESTING A device may be used to apply an auxiliary lifting load on the spring of a repaired valve to establish the set pressure in lieu of the tests required in RE-2010(a)(1) when such testing at full pressure: a. may cause damage to the valve being tested; or b. is impractical when system design considerations preclude testing at full pressure. While actual valve blowdown and valve performance characteristics cannot be verified, valve set pressure may be determined to an acceptable degree of accuracy using this testing technique provided, as a minimum, that: a. Equipment utilized is calibrated as required in RA-2255(m); 133 NATIONAL BOARD INSPECTION CODE b. The device and test procedures which have proved to give accurate results are used and followed; and provide a method of evaluating training effectiveness. As a minimum, training objectives for knowledge level shall include: c. A static inlet pressure is applied with the test medium specified in RE-2010; a. Applicable ASME Code and NBIC requirements; d. Adjustments are made in accordance with the valve manufacturer’s recommendations as to ensure proper lift and blowdown. b. Responsibilities within the organization’s quality system; and RE-3000 RE-3010 TRAINING AND QUALIFICATION OF PERSONNEL RE-3030 GENERAL It is essential that valve repair organizations ensure that their personnel engaged in repairs to pressure relief valves are knowledgeable and qualified within the scope of the repairs to be conducted. The National Board offers coordinated training courses for valve repair organization personnel to further their skills and knowledge in the repair of pressure relief valves. Many relief valve manufacturers also sponsor training courses on the repair and maintenance of their respective valve types and series. Pressure relief valve repair organizations are encouraged to have their personnel participate in these courses. It is also recommended that valve repair organizations cooperate and establish working relationships with valve manufacturers to help ensure the proper repair of the manufacturer’s specific valves. RE-3020 c. Knowledge of the technical aspects and mechanical skills for the applicable position held. QUALIFICATION OF PERSONNEL Each repair organization shall establish minimum qualification requirements for those positions within the organization as they directly relate to pressure relief valve repair. Each repair organization shall document the evaluation and acceptance of an individual’s qualification for the applicable position. RE-3040 ANNUAL REVIEW OF QUALIFICATION The repair organization shall annually review the qualifications of repair personnel to verify proficiency as well as compliance with the certificate holder’s quality system. This review shall include training records, documented evidence of work performed and, when necessary, monitoring job performance. The review shall be documented. CONTENTS OF TRAINING PROGRAM The repair organization shall establish a documented in-house training program. This program shall establish training objectives 134 Preparation of Technical Inquiries to the National Board Inspection Code Committee Appendix 1 135 NATIONAL BOARD INSPECTION CODE APPENDIX 1 — PREPARATION OF TECHNICAL INQUIRIES TO THE NATIONAL BOARD INSPECTION CODE COMMITTEE 1-1000 INTRODUCTION The NBIC Committee meets regularly to consider written requests for interpretations and revisions to the Code rules and to develop new rules, as dictated by technological development. The Committee’s activities in this regard are limited strictly to interpretations of the rules or to the consideration of revisions to the present rules on the basis of new data or technology. As a matter of published policy, the National Board does not approve, certify or endorse any item, construction, proprietary device or activity and, accordingly, inquiries requiring such consideration will be returned. Moreover, the National Board does not act as a consultant on specific engineering problems or on the general application or understanding of the Code rules. If, based on the inquiry information submitted, it is the opinion of the Committee that the inquirer should seek assistance, the inquiry will be returned with the recommendation that such assistance be obtained. b. Background State the purpose of the inquiry, which would be either to obtain an interpre-tation of Code rules or to propose consideration of a revision to the present rules. Provide concisely the information needed for the Committee’s understanding of the inquiry, being sure to include reference to the applicable Code Edition, Addenda, paragraphs and figures. If sketches are provided, they shall be limited to the scope of the inquiry. c. Inquiry Structure Prepare statements in a condensed and precise question format, omitting superfluous background information, and, where appropriate, composed in such a way that “yes” or “no” (perhaps with provisos) would be an acceptable reply. This inquiry statement should be technically and editorially correct. All inquiries that do not provide the information needed for the Committee’s full understanding will be returned. d. Proposed Reply State what it is believed the Code requires. If, in the inquirer’s opinion, a re v i s i o n t o t h e C o d e i s n e e d e d , recommended wording shall be provided. 1-2000 1-3000 INQUIRY FORMAT Inquiries shall be limited strictly to interpretations of the rules or to the consideration of revision to the present rules on the basis of new data or technology. Inquiries shall be submitted in the following format: a. Scope Involve a single rule or closely related rules. An inquiry letter concerning unrelated subjects will be returned. SUBMITTAL Inquiries shall preferably be submitted in typewritten form; however, legible handwritten inquiries will also be considered. They shall include the name, email address and mailing address of the inquirer and be mailed to the following address: 136 Secretary, NBIC Committee 1055 Crupper Avenue Columbus, OH 43229 614.847.1828 — Fax 614.888.8320 ext. 240 — Phone rferrell@nationalboard.org — Email Stamping and Nameplate Information Appendix 2 137 NATIONAL BOARD INSPECTION CODE APPENDIX 2 — STAMPING AND NAMEPLATE INFORMATION 2-1000 SCOPE When a pressure-retaining item is repaired or altered, the Certificate Holder shall attach a nameplate or stamp the item, except when otherwise permitted by these rules. Similarly, when pressure relief devices are repaired, the attachment of a nameplate is required. The specific requirements for nameplates/stamping are described in this Appendix. See Figures 2-1000-a thru 2-1000-g. 2-2000 GENERAL REQUIREMENTS FOR STAMPING AND NAMEPLATES Required data shall be in characters at least 5/32 in. (4 mm) high, except that characters for pressure relief valve repair nameplates may be smaller. Markings may be produced by casting, etching, embossing, debossing, stamping or engraving. The selected method shall not result in any harmful contamination of or sharp discontinuities to the pressure retaining item. The National Board code symbols (“R”, “VR”, and “NR”) are to be stamped; do not emboss. Stamping directly on items, when used, shall be done with blunt-nose continuous or blunt-nose interrupted dot die stamps. If direct stamping would be detrimental to the item, required markings may appear on a nameplate affixed to the item. The Certificate Holder shall use its full name as shown on the Certificate of Authorization or an abbreviation acceptable to the National Board. ing or nameplate. A single repair nameplate or stamping may be used for more than one repair to a pressure retaining item provided it is carried out by the same Certificate Holder. The date of each repair, corresponding with the date on the associated Form R-1, shall be stamped on the nameplate. The letters “RP” shall be stamped below the “R” symbol stamp to indicate organizations accredited for performing repairs or alterations to Fiber Reinforced Plastic items. The letter “G” shall be stamped below the “R” symbol stamp to indicate organizations accredited for performing repairs or alterations to Graphite Pressure vessels. 2-2100 ADDITIONAL STAMPING REQUIREMENTS FOR REPAIRS Stamping or nameplate shall be applied adjacent to the original manufacturer’s stamping or nameplate. A single repair nameplate or stamping may be used for more than one repair to a pressure retaining item provided it is carried out by the same Certificate Holder. The date of each repair, corresponding with the date on the associated Form R-1, shall be stamped on the namepate. 2-2200 ADDITIONAL STAMPING REQUIREMENTS FOR ALTERATIONS AND RE-RATINGS Stamping or nameplate shall be applied adjacent to the original manufacturer’s stamping or nameplate. Stamping or nameplate shall be applied adjacent to the original manufacturer’s stamp- 138 APPENDIX 2 — STAMPING AND NAMEPLATE INFORMATION 2-2300 ADDITIONAL STAMPING REQUIREMENTS FOR PARTS �� Stamping or nameplate shall be applied in a conspicuous location on the part. 2-2400 �� ADDITIONAL STAMPING REQUIREMENTS FOR PRESSURE RELIEF VALVES �� Pressure relief valve repair stamping or nameplate shall be applied adjacent to the original manufacturer’s stamping or nameplate. Note(2): To be indicated only when changed. �� Figure 2-1000-c — Required Markings for Re-ratings, with use of National Board Form R-2 �� Figure 2-1000-d — Required Markings for Parts Fabricated by Welding, with use of National Board Form R-3 Figure 2-1000-a — Required Markings for Repairs, with use of National Board Form R-1 �� Figure 2-1000-e — Required Markings for Repair of ASME/National Board “V”, “UV”, and “HV” Stamped Pressure Relief Valves Figure 2-1000-b — Required Markings for Alterations, with use of National Board Form R-2 139 NATIONAL BOARD INSPECTION CODE �� (TYPE/MODEL NUMBER) �� Figure 2-1000-f — Required Markings for Nuclear Repairs or Replacements Figure 2-1000-g — Required Markings for Repair or Replacement of Nuclear Pressure Relief Valves 140 Steam Locomotive Firetube Boiler Inspection, Repair and Storage Appendix 3 141 A04 NATIONAL BOARD INSPECTION CODE APPENDIX 3 — STEAM LOCOMOTIVE FIRETUBE BOILER INSPECTION, REPAIR, AND STORAGE A04 3-1000 A04 3-1010 of steam locomotive firetube boilers. These rules for the repair and alteration of steam locomotive boilers shall be used in conjunction with the applicable rules of this code. See general figures 3-1010-a and 3-1010-b. GENERAL REQUIREMENTS SCOPE This appendix is provided as a guide for inspection, repairs and alterations and storage FIGURE 3-1010-a 3-1010-a — Locomotive Boiler General Arrangement �� FIGURE 3-1010-b — Arrangement of Firebox Sheets (Staybolts Deleted for Clarity) Dome Course Crown Sheet Roof Sheet Combustion Chamber Side Sheet Throat Sheet Inside Throat Sheet 142 APPENDIX 3 — STEAM LOCOMOTIVE FIRETUBE BOILER INSPECTION AND REPAIR 3-1100 SPECIAL JURISDICTIONAL REQUIREMENTS 3-1400 Many jurisdictions have special requirements for locomotive boilers. Such requirements shall be considered in addition to those in this appendix. 3-1200 FEDERAL RAILROAD ADMINISTRATION (FRA) The FRA rules for steam locomotive boilers are published in the Code of Federal Regulations (CFR) 49CFR Part 230 Dated November 17,1999.8 All locomotives under FRA jurisdiction are documented on FRA Form 4 as defined in 49CFR Part 230. This document is the formal documentation of the steam locomotive boiler and is required to be completed prior to the boiler being placed in service. This document shall be used as the Data Report for the boiler, applicable to all repairs and alterations performed. National Board “R” Certificate Holders shall document their repairs and/or alterations on National Board Forms R-1 or R-2. These reports shall be distributed to the owner/user of the boiler who is required to incorporate them into a FRA Form 19 which becomes an attachment to the FRA Form 4. The design margin for all such repairs or alterations shall not be less than 4 based on ultimate tensile strength of the material. 3-1300 REQUIREMENTS FOR WELDING ACTIVITIES Before performing any welding activities, consideration shall be given to ensure the weldability of locomotive boiler materials. Special jurisdictional approval may be required prior to starting welding activity on locomotive boilers. Most steam locomotive boilers were manufactured in the first half of the 20th century or before. The calculations, formula and shop practices used are now distant history and quite difficult to obtain. The rules for riveted construction were last published by ASME in Section I Code, 1971 Edition. Appendix C, herein, provides a copy of the 1971 riveting rules from Parts PR and PFT. Appendix 3, herein, is based in part on the ASME Code, Section III, 1952 Edition9 which was the last published edition of the Steam Locomotive Code. The railroad industry has attempted to collect the old formula and some shop practices. These have been published by The Engineering Standards Committee for Steam Locomotives, Inc. (ESC) as Compendium, Volume 1, Compilation of Calculations.10 3-2000 LOCOMOTIVE FIRETUBE BOILER INSPECTION 3-2010 INSPECTION METHODS Plate thickness and depth of corrosion may be determined by use of the ultrasonic thickness testing process. Where access is possible, the depth of pitting may be determined by use of a depth micrometer or a pit gage. On stayed sections, the plate thickness readings should be taken on a grid not exceeding the maximum staybolt pitch at the center of each section of four staybolts. Additional 9 This Code is available from the National Board Copies of The Engineering Standards Committee for Steam Locomotives, Inc., Compendium, Volume 1, Compilation of Calculations may be obtained from the Strasburg Rail Road, P.O. Box 96, Strasburg, PA 17579, phone 717.687.8421. 10 8 FORMULA AND CALCULATIONS FOR STEAM LOCOMOTIVE BOILERS Steam locomotive inspection and maintenance standards, which is now codified at 49CFR Part 230 may be obtained at the FRA Web site. The final rule at www.fra.dot.gov/downloads/counsel/fr/slfr.pdf 143 NATIONAL BOARD INSPECTION CODE readings may be taken close to each staybolt to determine if localized thinning has occurred. Particular attention should be given to the joint between the staybolt and the plate. On unstayed sections, the plate thickness readings should be taken on a grid not exceeding 12 inch (300 mm) centers. Additional readings should be taken if conditions warrant. Cracks in plates may be located by the use of appropriate Nondestructive Examination (NDE) methods. Separation of plates at riveted seams may be detected by use of a feeler gage and magnifying glass or other applicable method. Varying the intensity of inspection lights may facilitate discovery of defects. Placement of the light to shine parallel to the surface is one method of detecting pits and surface irregularities. When inspecting internal stayed surfaces, placement of a light source within the stayed zone will aid the inspection. Broken staybolts may be detected by leakage through telltale holes and by hammer testing. Both methods are most effective when the boiler is under hydrostatic pressure of at least 95% MAWP. If a hydrostatic test can not be applied, the hammer test may be performed alone with the boiler drained. Visual inspection shall be performed as a supplement to all of the above. 3-2020 • • • • • • • Notes: 1. Broken rivet heads or cracked plates may result from sodium hydroxide cracking (caustic embitterment). 2. Riveted longitudinal lap seams should be given careful examination, using NDE if necessary, because this type of construction is prone to cracking. 3. When determining the extent of corrosion to rivet heads, it is important to know the rivet size and the type of rivet head used for the original construction. Corrosion can alter the appearance of these items and disguise the full extent of the damage. 4. Fire cracks extending to the rivet holes in riveted lap seams of firebox sheets may be acceptable under NBIC RB-4480. Welded & Riveted Repairs Welded and riveted repairs shall be inspected for: • • • • • • INSPECTION ZONES Leakage Separation of the plates Excessive or deep caulking of the plate edges and rivet head Seal welding of the plate edges and rivet heads Rivet heads that have been built up by or covered over completely by welding Rivets replaced by patch bolts Defective components of the seam Correct application of welded patches or weld application Correct application of riveting Cracks Separation of the plates Dents or other mechanical damage Leakage Riveted Seams and Rivet Heads Riveted seams and rivet heads shall be inspected for: Boiler Shell Course The boiler shell course shall be inspected for: • • • • • • • • Grooving Corrosion Cracks Pitting 144 Grooving or cuts Corrosion Cracks Pitting APPENDIX 3 — STEAM LOCOMOTIVE FIRETUBE BOILER INSPECTION AND REPAIR • • • Separation of the plates Dents or other mechanical damage Leakage Flue Sheets Flue sheets shall be inspected for: Note: 1. An accurate inspection often cannot be performed until the interior has been cleaned since mud and scale make it difficult to detect defects. Dome & Dome Lid The dome and dome lid shall be inspected for: • • • • • • • • • Grooving Corrosion, especially at the interior section attached to the boiler course Cracks Pitting Separation of plates Dents or other mechanical damage Leakage Stretched, bent or corroded dome studs Damage to the steam dome cover sealing surfaces Notes: 1. Close inspection should be made to the interior section at the joint attached to the boiler course. 2. If the dome studs are bent, a careful evaluation should be made of the lid for leakage and mechanical damage. Mud Ring The mud ring and mud ring rivets shall be inspected for: • • • • • • • • Mud and scale on the waterside Debris on the waterside Corrosion Grooving Cracks Separation of the firebox plates from the mudring Dents or other mechanical damage Leakage • • • • • • • • Grooving around flue holes, rivet seams and braces Pitting Fireside and waterside corrosion Fire cracks at riveted lap seams Cracks Bulges Leakage Excessive or deep caulking of the plate edges Note: 1. Corrosion is common at the bottom section of the front flue sheet. Close inspection of the joint between the front flue sheet and shell shall be made. Flanged Sheets The flanged section of all flanged sheets shall be inspected for: • • • • • • Pitting Corrosion Cracks Grooving Scale and mud deposits Correct fit up and alignment of the flanged sheet to the adjacent sheets Notes: 1. Corrosion is common at the bottom section of the front flue sheet. 2. The flanges should have a smooth uniform curvature and should make a smooth transition to the flat sheets. Stayed Sheets Stayed sheet shall be examined for: • • • • • • 145 Scale and mud deposits Grooving around staybolt holes Deterioration of the joint between the staybolt and the sheet Grooving on the waterside section Pitting Fireside and waterside corrosion NATIONAL BOARD INSPECTION CODE • • • • Overheating Fire cracks at riveted lap seams Cracks Bulges Notes: 1. Close inspection for fireside corrosion should be given to sections located behind refractory or grate bars. 2. Close inspection should be made for grooving on waterside surfaces of the stayed sheets just above the mudring. 3. Fire cracks extending to the rivet holes in riveted lap seam firebox sheets may be acceptable under RB-4480. Staybolts Staybolts shall be inspected for: • • • • • • • Cracks in or breakage of the body Erosion of the driven head from corrosion or combustion gases Staybolt head flush with or below the surface of the sheet Plugging of telltale holes except as permitted by 49 CFR Part 230.41 Waterside corrosion Staybolt heads that have been covered over by welding Correct application of seal welding to staybolt heads Notes: 1. An indicator of waterside corrosion on threaded staybolts is the lack of threads on the section of the staybolt body just above the sheet. 2. Broken staybolts may be detected by leakage through telltale holes and by hammer testing. Both methods are most effective when the boiler is under hydrostatic pressure of at least 95% MAWP. If a hydrostatic test can not be applied, the hammer test may be performed alone with the boiler drained. 3. When a broken stay is found, the stays adjacent to it should be examined closely because these may have become overstressed by addition of the load from the broken stay. 4. A telltale hole plugged by installation of a nail or pin may indicate the staybolt is broken and requires replacement. 5. The plugging of telltale holes by refractory to prevent build up of foreign matter in the telltale hole is permitted for locomotives operating under FRA jurisdiction per 49 CFR Section 230.41. 6. One indication that a threaded staybolt leaks during service is when the head of it is found to have been re-driven repeatedly. Flexible Staybolts & Sleeves Flexible staybolt sleeves and caps shall be inspected for: • • • • • • • • Corrosion Cracks Dents or other mechanical damage Leakage Damaged threads or welds Scale and mud accumulations inside the sleeve that could restrict bolt movement Correct application of welding to welded sleeves and welded caps Seal welding of threaded sleeves or threaded caps Notes: 1. An indicator of waterside corrosion on threaded staybolts is the lack of threads on the section of the staybolt body just above the sheet. 2. Broken staybolts may be detected by leakage through telltale holes and by hammer testing. Both methods are most effective when the boiler is under hydrostatic pressure of at least 95% MAWP. If a hydrostatic test can not be applied, the hammer test may be performed alone with the boiler drained. 3. On ball head flexible staybolts, one method of testing the stay for cracks or 146 APPENDIX 3 — STEAM LOCOMOTIVE FIRETUBE BOILER INSPECTION AND REPAIR 4. 5. 6. 7. breakage is to strike the ball head using a pneumatic hammer or hand hammer. Another method is to twist the ball head using a long handle wrench. Access to the ball head is gained by removing the cap from the sleeve. When a broken stay is found, the stays adjacent to it should be examined closely because these may have become overstressed by addition of the load from the broken stay. A telltale hole plugged by installation of a nail or pin may indicate the staybolt is broken and requires replacement. The plugging of telltale holes by refractory to prevent build up of foreign matter in the telltale hole is permitted for locomotives operating under FRA jurisdiction per 49 CFR Section 230.41. One indication that a threaded staybolt leaks during service is when the head of it is found to have been re-driven repeatedly. Girder Stay & Crown Bars Girder stays, crown bars and their associated fasteners including stays, rivets, pins, washers, nuts, thimbles, spacers and the adjacent sections of the firebox plates shall be inspected for: • • • • • • • • • Corrosion Cracks Mud and scale Correct fit and alignment of the girder stay or crown bar to the firebox plate surface, including flanged sections Correct fit and alignment of the thimbles, spacers and pins to the girder stay or crown bar and the firebox plates Dents or other mechanical damage Stays or rivets built up by or covered over completely by welding Leakage from the stay heads Seal welding of rivet heads • • Correct application of retainers to all nuts and fasteners Missing fasteners, nuts or retainers Notes: 1. An accurate inspection often cannot be performed until the girder stay or crown bar has been cleaned since mud and scale will make it difficult to detect defects. 2. When a broken stay is found, the stays adjacent to it should be examined closely because these may have become overstressed by addition of the load from the broken stay. Sling Stays Sling stays and their associated fasteners including the pins, retainers, washers, nuts and their associated attachment at eyes, girder stays or crown stays shall be inspected for: • • • • • • • • Corrosion Cracks Dents, wear or other mechanical damage Mud and scale Wear to the pin hole or expansion slot of the sling stay and mating component Correct application of retainers to the pins Missing fasteners, nuts or retainers Any of the above that would restrict movement of the sling stays Notes: 1. An accurate inspection often cannot be performed until the sling stay has been cleaned since mud and scale will make it difficult to detect defects. 2. When a broken or loose stay is found, the stays adjacent to it should be examined closely because these may have become overstressed by addition of the load from defective stay. 3. Special attention should be given to the row of sling stays adjacent to the flue sheet to ensure that these stays are not loose. 147 NATIONAL BOARD INSPECTION CODE Crown Stays & Expansion Stays Crown stays and expansion stays shall be inspected for: • • • • • • • • • • • • Cracks in or breakage of the body Dents, wear or other mechanical damage Erosion of the driven head from corrosion or combustion gases Stay head flush with or below the surface of the sheet Plugging of telltale holes, except as permitted by 49 CFR Part 230.41 Waterside corrosion Stay heads that have been covered over by welding Correct application of seal welding to stay heads Correct application of retainers to the pins Missing fasteners, nuts or retainers Correct fit and alignment of the stay assembly Any of the above that would restrict movement of the stay Notes: 1. An indicator of waterside corrosion on threaded stays is the lack of threads on the section of the stay body just above the sheet. 2. Broken stays may be detected by leakage through telltale holes and by hammer testing. Both methods are most effective when the boiler is under hydrostatic pressure of at least 95% MAWP. If a hydrostatic test can not be applied, the hammer test may be performed alone with the boiler drained. 3. When a broken stay is found, the stays adjacent to it should be examined closely because these may have become overstressed by addition of the load from broken stay. 4. A telltale hole plugged by installation of a nail or pin may indicate the stay is broken and requires replacement. 5. The plugging of telltale holes by refractory to prevent build up of foreign matter in the telltale hole is permitted for locomotives operating under FRA jurisdiction per 49 CFR Part 230.41. 6. One indication that a threaded stay leaks during service is when the head of it is found to have been re-driven repeatedly. 7. Special attention should be given to the row of stays adjacent to the flue sheet to ensure that these stays are not loose. Diagonal & Gusset Braces Diagonal and gusset braces, and their attachments, shall be inspected for: • • • • • • • Looseness Corrosion Cracks Welded repairs Missing pins or pin retainers Defective rivets Scale and mud deposits Notes: 1. Diagonal and gusset braces should be under tension. 2. The brace pins should fit the brace clevis and eye securely and be retained from coming out by some type of fixed or keyed retainer. 3. Diagonal braces having loop-type ends should be given close inspection for cracks and corrosion. The loop-type end is formed by the brace body being split, looped around and forged to the body. Some versions of it have a low margin of material to provide the required strength. Flues All boiler and superheater flues shall be inspected for: • • • • 148 Fire cracks Pitting Corrosion Erosion APPENDIX 3 — STEAM LOCOMOTIVE FIRETUBE BOILER INSPECTION AND REPAIR • • • • • • Obstructions in the flue interior Mud or scale buildup on the waterside Erosion or cracking of the flue ends, flue beads and/or seal welds Leakage Number of circumferential welded joints on flues repaired by re-ending Correct application including expanding/rolling and belling, beading or seal welding of the flue end Notes: 1. Erosion (cinder cutting) generally occurs to the firebox end of the flue. 2. Galvanic corrosion of the flue in the flue sheet may occur if flues are installed with copper ferrules. Superheater Units & Header Superheater units and the superheater header shall be inspected for: • • • • • • • • • • Pitting Cracks Erosion Corrosion Bulges Leakage Missing shields Missing or broken bands or supports on the superheater units Missing, damaged or welded attachment bolts, nuts, clamps, studs and washers Adequate structural bracing and support of the superheater header Arch Tubes, Water Bar Tubes & Circulators Arch tubes, water bar tubes and circulators shall be inspected for: • • • • • • • Erosion Corrosion Fire cracks Pitting Cracking of tube ends Overheating and blistering Bulges • • • Mud and scale buildup in the waterside Welded repairs Correct application including expanding/rolling and belling, beading or seal welding of the tube end Note: 1. Weld build up or welded patches are not permitted on arch tubes and water bar tubes of locomotives operating under FRA jurisdiction per 49 CFR Section 230.61. The defective tubes must be replaced. Thermic Syphons Thermic syphons shall be inspected for: • • • • • • • • • Erosion Corrosion Fire cracks Pitting Cracking of the syphon neck Overheating and blistering Bulges Mud and scale blockage in the wateside Broken or damaged staybolts Note: 1. Refer to sections Staybolts, Stayed Sheets and Flanged Sheets for additional inspection procedures. Fire Box Refractory Firebox refractory shall be inspected to ensure it is properly applied and maintained to prevent undesired flame impingement on the firebox sheets. Dry Pipe The dry pipe of boilers having dome mounted (internal) throttle valves shall be inspected for: • • • • • 149 Erosion Corrosion Cracks Adequate structural bracing, support and attachment to the boiler and dome Loose, bent or damaged rivets, nuts, bolts and studs NATIONAL BOARD INSPECTION CODE Note: 1. A steam leak into the dry pipe of a dome mounted (internal) throttle valve will send an unregulated flow of steam to the cylinders. Handhole Washout Doors Handhole washout doors and their mating surfaces shall be inspected for: Throttle & Throttle Valve The throttle handle and its mechanism shall be inspected for: • • • • • Proper operation Lost motion or looseness Adequate structural bracing, support and attachment to the boiler, dome and firebox Loose, bent or damaged nuts, bolts and studs Note: 1. The throttle handle shall be equipped with some type of locking mechanism to prevent the throttle from being opened by the steam pressure. Screw Type Washout Plugs, Holes & Sleeves Screw type washout plugs, holes and sleeves, especially those having square or Acme thread, shall be inspected for: • • • • • • • • Damaged or cracked threads on the plug, hole or sleeve. Corrosion Cracks Distortion Looseness Leakage Steam cuts to threads and sealing surfaces Twisting of the plug head or body Note: 1. When washout plugs are threaded with USF or NPT thread, the minimum number of threads in good condition in the threaded hole shall be adequate for the service. • • • • • • • • • • Damaged or cracked threads on the door studs Corrosion of door sealing surfaces and stud Cracks Stretching or bending of the door stud or handhole door Looseness Leakage and steam cuts Damage to the clamp Damage to the clamp seating surface on the sheet Confirmation that the handhole door makes unbroken line contact along the entire circumference of the sheet at the opening Material of the handhole door gaskets Correct repairs Notes: 1. Confirmation that the handhole door has unbroken line contact against sheet can be determined by performing a “blue check”. This requires applying a light coating of “contact blue” or “Prussian Blue” to the handhole door sealing surfaces. The door then is held against the sheet and removed. The transfer of the bluing will show the areas that contact the sheet surfaces. 2. The material of the handhole door gaskets should be reviewed with the operator to confirm that it meets the pressure and temperature requirements of the boiler. Threaded & Welded Attachment Studs Threaded and welded attachment studs shall be inspected for: • • • • • • 150 Corrosion, especially at the sheet Cracks Damaged threads Stretching or bending Looseness Leakage APPENDIX 3 — STEAM LOCOMOTIVE FIRETUBE BOILER INSPECTION AND REPAIR • Fusible Plugs Fusible plugs shall be inspected for: • • • • • • • • Corrosion Scale build up on the waterside Damage Tampering Leakage from the threads Height of the plug above waterside of crown sheet Evidence of melting or overheating Proper marking Water Glass, Water Column & Gage Cocks The water glass, water column and gage cock boiler connections and piping shall be inspected for: • • • • • • • • • • • • Mud and scale blockage Kinks or sharp, restricted or flattened bends in the piping Sags in the piping horizontal runs Condition of tubular or reflex water glass Correct type and material of piping and fittings Correct location, size and installation of the connections to the sheets Correct installation of the safety shield (if used) Correct installation of the viewing light (if used) Correct installation of the test and drain valves Proper installation Proper bracing to prevent vibration Loose, bent or damaged nuts, bolts and studs Steam Pressure Gage The steam pressure gauge, gauge cock boiler connections and piping shall be inspected for: • • Kinks or sharp, restricted or flattened bends in the piping Correct installation of the shutoff valve and syphon • • • • Proper size, type and material of piping and fittings Proper installation Proper lighting for viewing Proper bracing to prevent vibration Calibration Boiler Fittings & Piping The boiler fittings and associated piping shall be inspected for: • • • • • • • • Cracks Corrosion Pitting Leakage Looseness Loose, bent or damaged nuts, bolts and studs Adequate structural bracing, support, attachment and provision for expansion Proper size, type and material Boiler Attachment Brackets The boiler attachment brackets and associated components and fasteners used to secure the boiler to the frame shall be inspected for: • • • • • • • Correct installation Damaged or missing components Looseness Leakage Loose, bent or damaged rivets, nuts, bolts and studs Defective rivets Provision for expansion Fire Door The fire door, the locking mechanism and the operating mechanism shall be inspected for: • • • Safe and suitable operation Cracked, damaged or burned parts Loose, damaged or bent rivets, nuts, bolts and studs Note: 1. The locking mechanism should be inspected for correct operation to confirm 151 NATIONAL BOARD INSPECTION CODE it will not allow the door to open in the event the firebox becomes pressurized. Grates & Grate Operating Mechanism The grates shall be inspected for: • Cracked, damaged, burned or missing segments. The grate operating mechanism of rocking grates shall be checked for: • • • • • • Uniform operation of all segments Corrosion Worn or cracked linkage Correct fit of the shaker bar on the linkage Missing pins or pin retainers Loose, bent or damaged nuts, bolts and studs Smokebox The smokebox shall be inspected for: • • • • • • Erosion Corrosion Leakage Holes Looseness Loose, bent or damaged nuts, bolts and studs Smokebox Steam Pipes The smokebox steam pipes shall be inspected for: • • • • • • Erosion Corrosion Pitting Leakage Looseness Loose, bent or damaged nuts, bolts and studs Note: 1. Pitting from the casting process may be evident on cast thick wall steam pipes but may not constitute a defect. Ash Pan & Fire Pan The ash pan or fire pan shall be inspected for: • • • • • • • Corrosion Holes Looseness Loose or damaged rivets, nuts, bolt and studs Secure attachment to the frame or firebox Proper operation of the slides, clean out doors, dumping mechanism and dampers Proper sealing of the slides, clean out doors and dampers 3-2030 STEAM TESTING The following items shall be inspected during a steam test or when the boiler is in operation: • • • • • • • • • • 152 Test injectors and all other boiler feeding devices to confirm these operate correctly Confirm all water glasses or other water level indicating devices are operating properly Test operation of all test valves and drain valves of water glasses or other water level indicating devices Confirm all boiler controls operate correctly Test set and reseating pressure of safety valves as required Inspect boiler shell and rivet seams for leakage, cracks and bulges Inspect firebox plates for leakage, cracks and bulges Verify firebox refractory is satisfactory If boiler tube ends can be seen, inspect these for leakage and application of tube plugs If fusible plug can be seen, inspect it for leakage APPENDIX 3 — STEAM LOCOMOTIVE FIRETUBE BOILER INSPECTION AND REPAIR • • • • Inspect staybolts for leakage at the head and telltale hole Inspect boiler fittings, controls and associated piping for leakage Inspect water tanks, fuel tanks and associated piping for leakage Inspect firebox door for proper operation and locking 3-3000 LOCOMOTIVE FIRETUBE BOILER REPAIRS 3-3010 REPAIR OF STAYBOLT HOLES Staybolt holes may be repaired by welding, reaming or retapping to a larger size or by installing a flush patch. If the staybolt hole was threaded and is to be repaired by welding, the threads shall be removed prior to welding. 3-3020 THREADED STAYBOLTS (See Figure 3-3020) All threaded staybolts shall have either 11- or 12-thread pitch. Staybolt threads shall have a good close fit in sheets. Changing the staybolt thread pitch from 11 to 12 or the reverse shall be considered a repair. All staybolts shorter than 8 in.(200 mm) in length shall have telltale holes. Staybolt telltale holes in existing bolts shall be 3/16 in. (5 mm) to 7/32 in. (5.5 mm) in diameter and at least 1-1/4 in. (32 mm) deep in the outer FIGURE 3-3020 — Threaded Staybolts Taper Head Type Button Head Type Reduced Section Taper Head Crown Bolt-Type Staybolts Ball Socket-Type Flexible Staybolt Rigid Staybolt Equipped With Telltale Holes Bucking Bar For Ball Socket Flexible Staybolts 153 A04 NATIONAL BOARD INSPECTION CODE end. When staybolts 8 in. (200 mm) or less in length are replaced, they shall be replaced with staybolts that have a telltale hole 3/16 in. (5 mm) to 7/32 in. (5.5 mm) in diameter their entire length or with ones that have a 3/16 in. (5 mm) to 7/32 in. (5.5 mm) diameter hole in each end, drilled a minimum of 1-1/4 in. (31 mm) deep. On reduced body staybolts the telltale hole shall extend beyond the fillet and into the reduced section of the staybolt. Ball socket-type flexible staybolts may have telltale holes that extend from the threaded end of the bolt into the bolt head for a distance of 1/3 the spherical bolt head diameter. Telltale holes shall be reopened after driving. Staybolt length shall be sized so the length of bolt projecting through the sheet is not less than 1/8 in. (3 mm) and is sufficient to produce a full head after driving. The thread lead of both bolt ends and both firebox sheets shall be synchronized to permit the bolt to be installed without stripping the threads. When driving staybolt heads, the bolt’s opposite end shall be bucked or braced to prevent damaging the bolt’s threads. Bracing can be done several ways, such as using a pneumatic holder-on or a heavy steel bucking bar. Driving the heads on both ends of the staybolt simultaneously using two pneumatic rivet hammers (double gunning) is acceptable. Bolts are to be driven in such a manner as to expand radially the bolt body and threads into the sheet prior to forming the head. Merely driving over the head is not acceptable. Ball socket-type flexible staybolts shall not be braced by inserting a spacer under the cap. Installation of different diameter staybolts shall be considered a repair. 3-3030 BALL SOCKET-TYPE FLEXIBLE STAYBOLTS, SLEEVES, AND CAPS Welded flexible staybolt sleeves shall be applied as shown in Figures 3-3030-a through 3-3030-e. Sleeve axis shall be in alignment with centerline through holes in wrapper and firebox sheets. Welded sleeves and welded caps that leak at the welds or the sleeve shall be repaired. Wasted caps and sleeves shall not be repaired by weld buildup. Welded sleeves that have damaged cap threads shall be repaired or replaced. If the sleeve has wasted to less than 60% of the original thickness at the threaded cap section, it may be repaired by cutting off the threaded section and welding on a replacement section using full penetration welds. Threaded or welded sleeves that are cracked or have wasted to less than 60% of the original thickness at any section other than the threaded cap section shall be replaced. Threaded sleeves that leak where screwed into the boiler shell or wrapper sheet shall be repaired. Seal welding of one pass not exceeding 3/16 in. (5 mm) leg size is permissible for caulking purposes only. If seal welding is applied, the sleeve threads in the weld zone shall be removed prior to welding. New threaded sleeves seal welded after installation shall have the threads removed from the weld zone of the sleeve prior to welding. Threaded staybolt caps that leak shall not be seal welded. Substitution of one type of flexible staybolt sleeve by another type shall be considered a repair. 154 APPENDIX 3 — STEAM LOCOMOTIVE FIRETUBE BOILER INSPECTION AND REPAIR FIGURE 3-3030-a — Flexible Staybolts — Welded Sleeves, Caps, and Gaskets �� FIGURE 3-3030-b — Ball Socket-Type Flexible Staybolts Welded Cover Cap Type welded cover cap Welded Sleeve With Threaded Cover Cap Type welded sleeve FIGURE 3-3030-c — Half Sleeve Repair Procedure for Damaged Ball Socket Flexible Staybolt Welded Sleeve welded sleeve damaged at threaded section ball socket staybolt threaded cover cap �� ball socket staybolt Threaded Sleeve With Threaded Cover Cap Type remove threaded section down to gasket surface threaded cover cap threaded sleeve ball socket staybolt consisting of a spherical nut on a threaded rigid staybolt do not remove existing flexible staybolt ball socket staybolt 155 NATIONAL BOARD INSPECTION CODE FIGURE 3-3030-d — Half Sleeve Repair Procedure for Damaged Ball Socket Flexible Staybolt Welded Sleeve FIGURE 3-3030-e — Half Sleeve Repair Procedure for Damaged Ball Socket Flexible Staybolt Welded Sleeve half sleeve installed with full penetration weld half sleeve thread for standard flexible staybolt cap and gasket this surface machined for full penetration weld joint Where necessary for boiler expansion, ball socket-type flexible staybolts shall be positioned in such a manner as to not interfere with boiler expansion. Where individual bolts are replaced, care should be taken to assure that the stress load of the new bolt is compatible to the loading on adjacent bolts. 3-3050 The installation of unthreaded staybolts using full penetration welds is permissible. Note: Some locomotive boiler designs positioned the bolts by backing the bolt head away from the sleeve socket bottom a certain amount. A04 3-3040 WELDED INSTALLATION OF STAYBOLTS FIGURE 3-3040 — Seal Welded Staybolts staybolt head seal welded before driving SEAL WELDED STAYBOLTS (See Figure 3-3040) Replacement threaded staybolts may be seal welded before or after driving. Existing threaded staybolts that leak shall be repaired and may be seal welded. When used, seal welding shall not be the sole means of repair. 156 staybolt head seal welded after driving APPENDIX 3 — STEAM LOCOMOTIVE FIRETUBE BOILER INSPECTION AND REPAIR All staybolts shorter than 8 in. (200 mm) in length shall have telltale holes. Telltale hole diameter shall be 3/16 in. (5 mm) to 7/32 in. (5.5 mm) in diameter and at least 1-1/4 in. (31 mm) deep in the outer end. On reduced body staybolts, the telltale hole shall extend beyond the fillet and into the reduced section of the staybolt. Staybolts may have through telltale holes which are preferred. Ball socket-type flexible staybolts may have telltale holes that extend from the welded end of the bolt into the bolt head for a distance of 1/3 the spherical bolt head diameter. Where necessary for boiler expansion, ball socket-type flexible staybolts shall be positioned in such a manner as to not interfere with boiler expansion. Where individual bolts are replaced, care should be taken to assure that the stress load of the new bolt is compatible to the loading of adjacent bolts. Note: Some locomotive boiler designs positioned the bolts by backing the bolt head away from the sleeve socket bottom a certain amount. 3-3060 DIAGONAL BRACES, GUSSET BRACES AND THROAT SHEET/TUBESHEET BRACES Loose or damaged braces shall be repaired or replaced. Only steel braces may be repaired by welding. All such welds shall be full penetration. Wrought iron braces shall not be repaired by welding. When repairs or alterations are completed, the tightness and condition of the braces and their staybolts, rivets, clevises, eyes and pins shall be verified. 3-3070 THREADED STUDS Studs threaded into the boiler or firebox sheets shall not be seal welded. Installation of different diameter staybolts shall be considered a repair. FIGURE 3-3060 — Diagonal Braces, Gusset Braces and Throat Sheet / Tubesheet Braces Diagonal Brace Pin-Type Diagonal Brace Throat Sheet / Tubesheet Brace Solid-Type Brace Gusset Brace 157 NATIONAL BOARD INSPECTION CODE A04 3-3080 PATCH BOLTS (See Figure 3-3080) FIGURE 3-3080 — Patch Bolts Patch bolts may be replaced in kind. Seal welding of bolts is permitted. Typical Patch Bolts 3-3100 3-3110 FLUES, ARCH TUBES, CIRCULATORS, THERMIC SYPHONS Typical Patch Bolt Application FLUE AND TUBE RE-ENDING Each boiler tube or flue that is repaired by welding is limited to not more than three (3) circumferential welded joints. Re-ending is permitted provided the thickness of the tube or flue to be re-ended is not less than 90% of that required by Table 3-3110. Re-end pieces shall be new material and meet the thickness requirements of Table 3-3110. 3-3120 ARCH TUBES Arch tubes that are damaged or reduced to less than minimum required wall thickness shall be replaced in entirety by new one-piece arch tubes. Welded repairs or partial replacement is not permitted. Damage includes defects such as bulging, burns and cracks. When arch tubes are installed by rolling, the tube end shall project through the firebox sheet not less than 1/4 in. (6 mm) nor more than 3/4 in. (19 mm) before flaring. At a minimum the tube shall be expanded and flared at least 1/8 in. (3 mm) greater than the diameter of the tube hole. Additionally, the tube may be beaded and/or seal welded provided the throat of the seal weld is not more than 3/8 in. (10 mm) and the tube is finished rolled after welding. An arch tube installed by welding shall be considered a welded nozzle. Some acceptable weld joints are shown on Figure 3-3120. Ref. ASME Section I, Part PW 16.1 A change in tube attachment from rolled to welded or welded to rolled shall be considered an alteration. 3-3121 TUBE WALL THICKNESS FOR ARCH TUBES The minimum wall thickness of replacement arch tubes shall be as shown in Table 3-3121. Table 3-3121 Size Wall Thickness Up to 3 in. (75 mm) OD 8 BWG More than 3 in. (75 mm) OD to 4 in. (100 mm) OD 7 BWG 3-3130 THERMIC SYPHONS For repairs to syphon knuckles see Repair of Firebox and Tubesheet Knuckles, and Figures 3-3130-a and 3-3130-b. 158 APPENDIX 3 — STEAM LOCOMOTIVE FIRETUBE BOILER INSPECTION AND REPAIR TABLE 3-3110 MAXIMUM ALLOWABLE WORKING PRESSURES FOR STEEL TUBES OR FLUES FOR FIRETUBE BOILERS FOR DIFFERENT DIAMETERS AND GAGES OF TUBES CONFORMING TO THE REQUIREMENTS OF SPEC. SA-176, SA-192, SA-209, OR SA 210* Outside diameter of tube, inches D Minimum gage, BWG 13 t = 0.095 12 t = 0.109 11 t = 0.120 10 t = 0.134 9 t = 0.148 8 t = 0.165 7 t = 0.180 6 t = 0.203 5 t = 0.220 4 t = 0.238 1 470 690 — — — — — — — — 1-1/2 320 460 570 720 860 — — — — — 1-3/4 270 400 490 620 740 890 — — — — 2 240 350 430 540 650 780 900 — — — 2-1/4 210 310 380 480 580 690 800 960 — — 2-1/2 190 280 350 430 520 630 720 860 970 1080 3 160 230 290 360 430 520 600 720 810 900 3-1/4 — 210 270 330 400 480 550 660 750 830 3-1/2 — 200 250 310 370 450 520 620 690 770 4 — 180 220 270 330 390 450 540 610 680 4-1/2 — 160 190 240 290 350 400 480 540 600 5 — — 180 220 260 320 360 430 490 540 5-3/8 — — 160 200 240 290 340 400 450 500 5-1/2 — — — 200 240 290 330 390 440 490 6 — — — 180 220 260 300 360 410 450 P = {(t–0.065)/D} x 15.550 where P = maximum allowable working pressure, pounds per square inch, t = minimum wall thickness, inches, D = outside diameter of tubes, inches. For pre given by the formulas. For pressures below those given in the table, the gage thickness shall be not less than the minimum given in the table. * These values have been rounded out to the next higher unit of 10. Ref: 1952 ASME, Sec. III – Boilers of Locomotives TABLE 3-3110M MAXIMUM ALLOWABLE WORKING PRESSURES FOR STEEL TUBES OR FLUES FOR FIRETUBE BOILERS FOR DIFFERENT DIAMETERS AND GAGES OF TUBES CONFORMING TO THE REQUIREMENTS OF SPEC. SA-176, SA-192, SA-209, OR SA 210* Outside diameter of tube, mm D Minimum gage, BWG, to mm 13 t = 2.4 12 t = 2.8 11 t = 3.1 10 t = 3.4 9 t = 3.8 8 t = 4.2 7 t = 4.6 6 t = 5.2 5 t = 5.6 4 t = 6.1 25 3220 4930 — — — — — — — — 40 2010 3080 3890 4690 5760 — — — — — 45 1790 2740 3460 4170 5120 6080 — — — — 50 1610 2470 3110 3750 4610 5470 6330 7610 — — 60 1340 2060 2590 3130 3840 4560 5270 6350 7060 7950 65 1240 1900 2390 2890 3550 4210 4870 5860 6520 7340 75 — 1650 2080 2500 3080 3650 4220 5080 5650 6360 85 — — 1830 2210 2710 3220 3720 4480 4990 5620 90 — — 1730 2090 2560 3040 3520 4230 4710 5300 100 — — 1560 1880 2310 2740 3170 3810 4240 4770 115 — — 1350 1630 2010 2380 2750 3310 3690 4150 125 — — — 1500 1850 2190 2530 3050 3390 3820 135 — — — 1390 1710 2030 2350 2820 3140 3540 140 — — — — 1650 1960 2260 2720 3030 3410 150 — — — — 1540 1830 2110 2540 2830 3180 P = {(t–1.651)/D} x 107510 where P = maximum allowable working pressure, kilopascals (kPa), t = minimum wall thickness, mm, D = outside diameter of tubes, mm. For pre given by the formulas. For pressures below those given in the table, the gage thickness shall be not less than the minimum given in the table. * These values have been rounded out to the next higher unit of 10. Ref: 1952 ASME, Sec. III – Boilers of Locomotives 159 NATIONAL BOARD INSPECTION CODE FIGURE 3-3120 — Welded Installation of Arch Tube tc tn (y) 1 tw tn tc tn but not less than 1/4 in. (6 mm) tc tn but not less than 1/4 in. (6 mm) tw 1 Section 1-1 t = thickness of vessel shell or head, in. tn = thickness of nozzle wall, in. tw = dimension of partial penetration attachment welds (fillet, single bevel, or single J), measured as shown in Figure PW-16.1, in. tc = not less than the smaller of 1/4 in. (6 mm) or 0.7 tmin. (inside corner welds may be further limited by a lesser length of projection of the nozzle wall beyond the inside face of the vessel wall) tmin = the smaller of 3/4 in. (19 mm) or the thickness of either of the weld parts joined by a fillet, single bevel, or single J-weld, in. FIGURE 3-3130-a — Locomotive Firebox Thermic Syphon Installation �� FIGURE 3-3130-b — Thermic Syphon Repair full penetration welds length to suit section on w-w syphon neck repair flush patch on staybolt syphon body 160 full penetration weld radiographically examined after welding APPENDIX 3 — STEAM LOCOMOTIVE FIRETUBE BOILER INSPECTION AND REPAIR All weld repairs to the unstayed sections of the syphon neck and body shall be radiographically examined. 3-3140 CIRCULATORS All butt welds on circulators shall be radiographically examined. Welds applied to the circulator/firebox sheet joint shall be in accordance with the weld requirements for arch tubes. See Figure 3-3120. 3-3200 REPAIRS AND ALTERATIONS TO BOILER BARREL UNSTAYED AREAS Defects such as cracks and wastage may be repaired by weld buildup, a welded flush patch or a riveted patch. Installation of a riveted patch shall be considered an alteration. Prior to repairing cracks, the plate shall be examined for defects. Affected sections shall be repaired. Weld buildup shall not be used if the affected section of plate has wasted below 60% of the minimum required thickness. If the cracked section of plate is retained and is to be repaired by installation of a riveted patch, the crack may be stopped by drilling stop holes at each end or removed by a method such as grinding, cutting or machining. Results of stop drilling or crack removal shall be verified by NDE. Welded repairs at or near riveted seams requiring preheating or postweld heat treatment shall be carefully made in order to prevent loosening in the riveted seams, especially when localized heating is used. Where necessary to control expansion or to gain access for welding, rivets at the defective section and to each side of it may be removed. Reuse of rivets and staybolts is prohibited. All welded repairs to boiler barrel unstayed areas shall be radiographically examined in accordance with the ASME Code, Section I when the size of the repaired area is greater than the maximum size of an unreinforced opening as calculated in accordance with the latest edition of the ASME Code, Section I. Riveted patches may be any shape or size provided the lowest patch efficiency is equal to or greater than the lowest equivalent seam efficiency of the boiler course to which it is applied. Ref: ASME Code, Section I. The factor of safety of all riveted patches shall not be less than four (4) for locomotives operating under Federal Railroad Administration regulations. 3-3300 REPAIRS AND ALTERATIONS TO BOILER BARREL STAYED AREA 3-3310 FIREBOX SHEET REPAIR Cracks in all stayed firebox sheets may be repaired by welding or the installation of a flush patch. If the crack extends into a staybolt or rivet hole, the staybolt or rivet shall be removed prior to making the repair. 3-3320 FIREBOX PATCHES Patches may be any shape provided they are adequately supported by staybolts, rivets, tubes or other forms of construction. Patches on stayed surfaces should be designed so 161 A04 NATIONAL BOARD INSPECTION CODE FIGURE 3-3320 — FIGURE 3-3330 — Stayed Firebox Sheet Grooved or Wasted at Mudring Figure 3-3320-a illustrates what would be considered a saw-tooth patch. Its advantage is that a maximum amount of welding is obtained for securing a given patch and by zig-zagging the weld, the weld is supported by three (3) rows of staybolts instead of two (2). Its disadvantage is its irregular shape which causes greater difficulty in fitting and applying. Firebox Sheets First Staybolt Row Sheet Wasted Below Mudring Waterside D EL W Figure 3-3320-a - Saw-Tooth Patch D EL W Mudring Rivet Mudring Figure 3-3320-b - Rectangular Shaped Patch All rectangular or angled patches shall have adequate radius at all corners. Minimum radius to be not less than three (3) times plate thickness. D EL W Patches shall fit flush on the waterside of the sheet. Misalignment shall not exceed one quarter (1/4) plate thickness on edge alignment with the sheet water side. Figure 3-3320-c - Diamond Shaped Patch weld seams pass between staybolt rows. See Figure 3-3320. Patches are to be flush type, using full penetration welds. If the load on the patch is carried by other forms of construction, such as staybolts, rivets or tubes, radiographic examination of the welds is not required. If the patch includes an existing riveted seam, the patch shall be riveted at that seam. Changing a riveted seam to a welded seam is considered an alteration. Staybolts and rivets should be installed after welding of patch is completed. Reuse of staybolts and rivets is prohibited. Weld seams parallel to a knuckle shall be located no closer to the knuckle than the point of tangency of the knuckle unless the weld is radiographically examined. Weld seams not located in the knuckle are preferred. See Figure 3-3350-b. Patches shall be made from material that is at least equal in quality and thickness to the original material. 162 APPENDIX 3 — STEAM LOCOMOTIVE FIRETUBE BOILER INSPECTION AND REPAIR 3-3330 A04 REPAIR OF STAYED FIREBOX SHEETS GROOVED OR WASTED AT THE MUDRING (See Figure 3-3330) FIGURE 3-3340 — Mudring Repair Grooved or wasted firebox sheets having greater than 60% of the minimum required thickness remaining may be repaired by weld buildup provided the wastage does not extend below the waterside surface of the mudring and the strength of the structure will not be impaired. If extensive welding is required, the affected area shall be removed and replaced with a flush patch. mudring remove firebox sheets for access If the sheet thickness has been reduced to less than 60% of the minimum required thickness, the affected section shall be removed and replaced with a flush patch. If wastage and grooving extends below the mudring waterside surface and if the plate thickness remaining has been reduced to less than the minimum required thickness, the affected section shall be removed and replaced with a flush patch. Flush patches shall be arranged to include the mudring rivets and at least the first row of staybolts above the mudring. A04 3-3340 MUDRING REPAIRS (See Figure 3-3340) Pitted and wasted sections of mudrings may be built up by welding provided the strength of the mudring will not be impaired. Where extensive weld build-up is employed, the Inspector may require an appropriate method of NDE for the repair. full penetration weld quality and thickness to the original material. Patches shall fit flush on waterside surfaces. Where necessary, firebox sheets on both sides of the defect may be removed to provide access for inspection and welding. 3-3350 REPAIR OF FIREBOX AND TUBESHEET KNUCKLES Welds within the points of tangency of a knuckle are permitted. Welds with angles of less than 45 degrees to the longitudinal axis of the knuckle shall be radiographically examined. See Figures 3-3350-a through 3-3350-f. Any patch not supported by means other than the weld, such as rivets, staybolts, tubes or other forms of construction, shall have all weld seams radiographically examined. Cracked or broken mudrings may be repaired by welding or installation of flush patches using full penetration welds. Patches shall be made from material that is at least equal in 163 NATIONAL BOARD INSPECTION CODE FIGURE 3-3350-a — Firebox Tubesheet Knuckle Repair �� transverse crack in tubesheet knuckle � �� see layout method in Figure 15A parallel crack in tubesheet knuckle �� knuckle � staybolts FIGURE 3-3350-b — Repair of Firebox and Tubesheet Knuckles tubesheet �� point of tangency of knuckle knuckle patch welded through tube holes line of weld is to be as nearly horizontal as conditioning will permit �� top flue knuckle radius flue sheet welds located no closer to knuckle than point of tangency do not require radiographic examination knuckle patch welded around tube holes FIGURE 3-3350-b1 — Layout Method of Determining Knuckle Weld Angle longitudinal axis point � PT R b To find the points of tangency (PT) of the knuckle: b b = R - (R * cos ) Where: R = inside knuckle radius Reference Longitudinal Axis of Knuckle weld ß = Angle of weld relative to the Reference Longitudinal Axis of Knuckle. Illustrations are of inside surface of knuckle. 164 � � PT ß � �� Longitudinal Axis Point True Longitudinal Axis APPENDIX 3 — STEAM LOCOMOTIVE FIRETUBE BOILER INSPECTION AND REPAIR FIGURE 3-3350-c — Repair of Firebox and Tubesheet Knuckles STAYED PATCH APPLIED TO BUTT WELDED SEAM staybolt rows point of tangency of knuckle FIGURE 3-3350-d — Firebox Throat Sheet Knuckle typical flush patches installed with full penetration welds knuckle patch length patch length tube or staybolt rows weld seams located beweld seams located between tween tube rows below staybolt rows and above first staybolt rows or tube rows tube row or staybolt row STAYED PATCH APPLIED TO RIVETED SEAM riveted seam patch length weld seam located above first tube row or staybolt row patch length weld seam located between tube rows or staybolt rows REPAIRS REQUIRING RADIOGRAPHIC EXAMINATION OF WELD SEAMS if access for welding or riveting is required, remove section of exterior or interior sheets patch not supported by tubes, staybolts or rivets weld seam located in knuckle FIGURE 3-3350-e — Backhead Knuckle Repair FIGURE 3-3350-f — Fire Door Opening Repair transverse weld if access for welding and riveting is re-quired, remove section of exterior or interior sheets SEC A-A typical flush patch original wrapper sheet new rivets SEC A-A patch length patch bolts or rivets staybolts patch installed with full penetration welds and either patch bolts or rivets weld located between staybolt rows 165 flush patch installed with full penetration welds NATIONAL BOARD INSPECTION CODE Patches shall be formed to proper shape and curvature. Damaged tubesheet holes may be repaired by welding. Wasted sections of knuckles that have not wasted below 60% of the minimum required thickness may be repaired by weld buildup provided the strength of the structure will not be impaired. Where weld buildup is employed, the Inspector may require an appropriate method of NDE for the repair. Sections of tubesheets damaged or wasted to less than 60% minimum required thickness shall be repaired by installing a flush patch using full penetration welds. Wasted sections of knuckles that have wasted below 60% of the minimum required thickness shall be replaced. A04 3-3360 Sections of tubesheets that have not wasted below 60% minimum required thickness may be repaired by weld buildup provided the strength of the structure will not be impaired. Where weld buildup is employed, the Inspector may require an appropriate method of NDE for the repair. TUBESHEET REPAIRS (See Figure 3-3360) Cracked tubesheet ligaments may be repaired by welding using full penetration welds. FIGURE 3-3360 — Tubesheet Repairs 3-3400 SEAMS AND JOINTS 3-3410 CAULKING RIVETED SEAMS AND RIVET HEADS A04 (See Figure 3-3410) Caulking refers to the sealing of plate seams and rivet heads by driving the edge of one surface onto the other by use of an impact tool. Riveted seams and rivet heads may be caulked in accordance with ASME Section I, 1971. typical tubesheet flush patches FIGURE 3-3410 Caulking Tool tubesheet welded around tube holes Caulked Edge of Plate tubesheet welded through ligaments and tube holes 166 APPENDIX 3 — STEAM LOCOMOTIVE FIRETUBE BOILER INSPECTION AND REPAIR 3-3500 approximately horizontal. Connections must be applied without pockets, traps, sags or syphons. Tubular water gage glasses must be equipped with a protection shield. THREADED OPENINGS IN VESSEL WALLS, BUSHINGS AND WELDED NOZZLES (WASHOUT PLUG HOLES AND OTHER CONNECTIONS) Threaded openings in vessel walls and welded nozzles with damaged threads that cannot be repaired by retapping or rethreading may be repaired by welding a nozzle in the sheet. The nozzle shall be of such a size as to not interfere with proper washout and inspection. Threaded bushings and nozzles found to be defective shall be replaced. Seal welding is not permitted. New threaded bushings equipped with shoulders may be seal welded at the shoulder. New threaded bushings without shoulders that are seal welded after installation shall have the threads removed from the weld zone of the bushing prior to welding. Locomotive water gage glasses shall be provided with one top and one bottom shutoff cock and a means to illuminate each glass. Each top and bottom shutoff cock or valve shall be of such through flow construction as to prevent stoppage by deposits of sediments. Straight run globe valve of the ordinary type shall not be used on such connections. See Figure 3-3610. The water gage glass connection and pipe connection shall be fitted with a drain cock or valve having an unrestricted opening of not less than 3/8 in. (10 mm) in diameter to facilitate cleaning. The top and bottom water gage glass fitting are to be aligned, supported and secured so as to maintain the alignment of the water gage glass. Threaded holes with damaged threads may be repaired by weld buildup and retapping. The threads shall be removed prior to welding. A04 3-3600 3-3610 FITTINGS AND GAGES WATER GAGE CONNECTION Water gage glasses shall be applied so that the lowest water reading in the water gage glass of a horizontal firetube boiler on level track shall be at least 3 in. (75 mm) above the highest point of the tubes, flues or crown sheet. The bottom mounting for water gage glass (and for water column if used) must not extend less than 1-1/2 in. (38 mm) inside the boiler and beyond any obstacle immediately above it. The passage must be straight and 167 FIGURE 3-3610 — Straight Run Globe Valve Not Permitted NATIONAL BOARD INSPECTION CODE The lower edge of the steam connection to a water column or water gage glass in the boiler shall not be below the highest visible water level in the water gage glass. There shall be no pockets, traps, sags or syphons in the piping which will permit the accumulation of sediments. The upper edge of the water connection to a water gage glass and the boiler shall not be above the lowest visible water level in the water gage glass. There shall be no pockets, traps, sags or syphons in the connection. 3-3700 MATERIAL LIST FOR STEAM LOCOMOTIVE BOILERS The following list is intended as a basic guideline only and covers just the basic carbon steel and some alloy steel material specifications. Other alloy materials may be available for these applications if necessary. Hollow Cylindrical Pressure Retaining Parts SA-105 Forgings SA-675 Bar Stock Superheater Unit Bolts & Nuts Bolts - SA-193, Nuts -SA-194 Pipe Flanges SA-181, SA-105 Pipe SA-106, SA-53 seamless Bronze Castings & Washout Plugs SB-61, SB-62 a. SA-516 steel is recommended for firebox repairs. It is a fine grain that accepts flanging and bending with less chance of cracking than course grain steels such as SA-515 or SA-285 Grade C. Course grain steels have, on occasion, been found to crack or split after complicated flanging, bending and forming. b. SA-36 is not to be used to make any pressure retaining part such as shells, staybolt sleeves or caps. Application Specification Boiler Tubes & Flues, Arch Tubes Superheater Units SA-178 Grade A, SA-192, SA-210 Boiler & Firebox Plate SA-285 Grade C, SA-515, SA-516, SA-203, SA-204 Staybolts SA-675, SA-36, ASTM A-31 Staybolt Sleeves and Caps SA-105 Forging, SA-675 Boiler Braces SA-675, SA-36 d. When staybolt material tensile strength is stronger than that of the firebox sheets, the firebox sheets deflect instead of the staybolts, which can result in the sheets developing cracks and leaking staybolts. In addition, high tensile strength steels are difficult to drive. Rivets SA-675, ASTM A-31 3-4000 Forged Parts & Fittings SA-105, SA-181 Pressure Retaining Steel Casings SA-216, SA-217 c. When rivets are made from SA-675, the finished rivets must meet the physical and test requirements of the original ASME rivet specification ASTM A-31 Grade A or B. GUIDELINES FOR STEAM LOCOMOTIVE STORAGE The steam locomotive guidelines published A04 herein list the general recommendations for storage of locomotive boilers and locomotives. 168 APPENDIX 3 — STEAM LOCOMOTIVE FIRETUBE BOILER INSPECTION AND REPAIR The exact procedures used by the owner/ operator must be reviewed by the railroad mechanical officers/engineers and be based on the conditions and facilities at the railroad shop or storage facility. 3-4010 STORAGE METHODS The methods for preparing a steam locomotive for storage depend upon several factors, including: • • • • • • The anticipated length of time the locomotive will be stored. Whether storage will be indoors or outdoors. Anticipated weather conditions during the storage period. The availability of climate-controlled storage. Type of fuel used. Equipment available at the storage site. Indoor storage can be broken into two types: Indoor with climate control and indoor without climate control. Outdoor storage can also be broken into two types: outdoors during a warm time of year or in a geographic location where it can reasonably be expected to be above freezing during storage and outdoors during a time period or in a geographic location where it can be expected that freezing temperatures will occur during storage. Locomotive boilers may be stored using the “wet method” or the “dry method.” Before any method of storage, the boiler must be thoroughly washed out with all mud and scale removed from the mudring, crownsheet, bottom of the barrel and the top of the firing door. 3-4020 WET STORAGE METHOD When utilizing the “wet storage method” the A04 boiler is completely filled with treated water to exclude all air. NOTE: This method cannot be used if the locomotive is exposed to freezing weather during storage. Chemicals may be added to the storage water to further inhibit corrosion. However, depending on the chemical used the treated water may have to be disposed of as a hazardous waste to prevent chemical contamination of the surrounding property. The procedure applies only to the sections of the boiler that contain water. The firebox interior, cylinders, piping and auxiliary equipment of the locomotive still require draining, preservation and dry storage. 3-4030 DRY STORAGE METHOD When utilitizing the “dry storage method” A04 the boiler is completely emptied of water, dried out and allowed to stand empty. Several variations of the “dry method” may be used. These include but are not limited to: • • • Air tight storage with moisture absorbent placed in trays in the boiler; Air tight storage with the boiler filled with inert gas to exclude all oxygen; Open air storage with the mud ring washout plugs removed to enable air circulation for evaporation of formed moisture. Each variation has positive and negative A04 points that must be taken into account before use. If the boiler is filled with inert gas such as nitrogen, care must be taken because this method can result in asphyxiation of personnel if the gas escapes the boiler through a leaking valve or washout plug and enters a pit, sump or enclosed room. In addition, the 169 NATIONAL BOARD INSPECTION CODE boiler must be completely vented to remove all gas, then tested and declared gas free before personnel may enter. Although the use of dry storage with several washout plugs removed for air circulation is the most common method, there are some potential drawbacks. The boiler interior may be subject to moisture forming from condensation created from humidity changes in the ambient air. Small animals may take up residence inside if screens are not used to cover handholes and washouts. Before storage the boiler must be thoroughly washed out with all mud and scale removed from the mudring, crownsheet, bottom of the barrel and top of the firing door. Any mud or loose scale left in the boiler will retain moisture leading to corrosion. After washing, all water must be removed and the boiler dried before storage. A portable gas or electric heater placed in the firebox to aid evaporation and drying along with a vacuum used to siphon water out via the lower washout plugs is recommended. NOTE: Use of the common railroad drying out procedure of building a small wood fire in the firebox is not recommended because of the danger of overheating the firebox sheets. The typical railroad dry storage method required blow down of the boiler until empty while steam pressure registered on the gauge and removal of the washout plugs while the shell plates were hot and there was no steam pressure. This allowed the heat remaining in the boiler plates to evaporate all remaining water in the boiler. However, this method may result in staybolt damage from temperature change and requires extreme care, if used. Oil should not be applied to the interior surfaces of the boiler because it is difficult to remove. Further, all of the oil must be removed before steaming or it will form scale and contribute to foaming. 3-4040 RECOMMENDED GENERAL PRESERVATION PROCEDURES When the locomotive is under steam, inspect all piping, fittings and appliances for steam and water leaks that may introduce moisture into the lagging. Repair all leaks as necessary and remove wet lagging. Wet lagging can accelerate corrosion of the boiler external surfaces, especially staybolt sleeves and caps. Thoroughly wash the boiler and firebox and remove all mud and scale from the mudring, crownsheet, bottom of the barrel and top of the firing door. Any mud or loose scale left in the boiler will retain moisture leading to corrosion. Wash out thermic siphons, arch tubes and circulators. To protect the boiler interior during storage, dry the boiler by using compressed air to blow out as much water as possible. A portable heater placed in the firebox to warm the boiler to 200°F (95°C) along with a vacuum used to siphon water out via the lower washout plugs can aid evaporation and drying of any moisture that collects in low or impossible-to-drain locations without harming the sheets. CAUTION: To prevent a build up of steam pressure during the drying process, the steam dome cover or top washout plugs should be removed to enable the moisture to escape. In addition, the driving wheels should be blocked and the throttle and cylinder cocks should be opened to permit any steam that forms in the superheater units to escape. Superheater units, by nature of design, can be difficult to drain and dry out. Typical methods include: a. Pressurize the boiler with compressed air with the locomotive stationary and blocked in place. Using the throttle to regulate the airflow, allow the air to blow through the entire bank of superheater units and dry pipe and discharge into the cylinders. The cylinder cocks must be open. 170 APPENDIX 3 — STEAM LOCOMOTIVE FIRETUBE BOILER INSPECTION AND REPAIR b. Pressurize the boiler with compressed air then operate the locomotive under air pressure over a short distance of track. The cylinder cocks should be opened during the initial operation to prevent damaging the cylinders by hydraulic lock. If the air pressure draining procedure is not practical or can not be accomplished correctly, the superheater units can be protected against trapped moisture by filling the entire superheater bundle with a standard antifreeze/water mixture or with diesel fuel. A04 NOTE: The air pressure dryout methods “1” or “2” may have to be performed several times to discharge all of the moisture. Refer to Section 3-4050, “Use of Compressed Air To Drain Locomotive Components,” for additional information on compressed air drying. NOTE: If the locomotive is operated under air pressure, the air brake system should be made operational to provide safe stopping or other steps taken to control and stop the locomotive. After drying, it will be necessary to either vent the boiler or to place containers of desiccant inside the boiler through the dome cap to absorb any condensation that may occur during storage. Venting the boiler to allow air circulation is accomplished by leaving two or more of the lower washout plugs out and opening the vent valve on the top of the boiler. A vent line consisting of two 90° elbows and pipe nipples should be installed in the vent valve to locate the opening to the downward direction in order to keep rain or snow from entering the open valve. valves, etc. Repair all gaps or damaged jacket sections as necessary. Consideration should be given to covering the entire locomotive and tender with a tarp. Otherwise, all jacket openings should be covered to prevent the entrance of rain or snow. Where necessary, apply a waterproof covering over the exposed or open sections. b. The smokestack should be sealed by applying a wood and sheet rubber cover held in place by clamps or a through bolt. c. The safety valves should either be covered or removed, with plugs or caps installed in the holes if the valves are removed. d. The dynamo, air pump and feedwater heater exhausts should also be covered. e. Empty and clean the smokebox, front tube sheet, superheater units, steam pipes and front end plates of all coal, ash or burnt oil. This work is especially critical at the bottom section of the smokebox and front tubesheet rivet flange. The smokebox door should be sealed by applying a gasket or sealant and any other air openings in the smokebox sealed. The exhaust nozzle should be sealed by applying a wood and sheet rubber cover held in place by clamps. f. If the locomotive will be stored outdoors, the A04 following should be completed: a. Inspect the boiler jacket and confirm it is tight with no gaps leading into the lagging or shell. Pay close attention to areas at shell openings such as for studs, safety The potential for corrosion of the smokebox interior can be further minimized by applying coating of outdoor paint or primer. All inspection of the smokebox and front tubesheet must be accomplished before painting since it will cover up many types of defects. The coating will burn off quickly when the locomotive is returned to service. g. Thoroughly clean the firebox sheets, flues and superheater return bends of all ash and clinker. 171 NATIONAL BOARD INSPECTION CODE h. On coal burners, empty and clean the grates and ash pan of all coal and ash completely. This work is especially critical at the sections between the grate bearers, the mud ring rivets and firebox sheets; and from the grate segment air openings. On oil burners, care should be taken to remove ash from between the flash wall refractory and the firebox sheets. i. j. blocked in place. Using the throttle to regulate the airflow, allow the air to blow through the dry pipe and discharge into the cylinders. The cylinder cocks must be open. 2. Pressurize the boiler with compressed air then operate the locomotive under air pressure over a short distance of track. The cylinder cocks should be opened during the initial operation to prevent damaging the cylinders by hydraulic lock. If the locomotive will be out of service for longer than 12 months, removal of the brick arch or flash wall refractory that extends above the mudring should be considered to prevent condensation and corrosion from occurring between the brick and the steel. Temporary removal of the brick arch or flash wall to permit application of a preservative to firebox sides, arch tubes or siphons should be considered for shorter storage periods. All appliances and piping that might contain water or condensation should be drained and blown dry using dry compressed air. This includes the air and equalizing reservoirs, dirt collectors, injectors, cylinders, stoker engine cylinders, dynamos, the steam and water sides of feedwater heaters and pumps, the steam side of air pumps, the steam side of lubricators, atomizers, oil tank heaters, gauge siphons, tank hoses and cab heater piping. A small quantity of valve oil should be sprayed into the valve chambers, cylinders and the steam side of all appliances to protect against corrosion. Refer to the Section “Use of Compressed Air To Drain Locomotive Components” for details. k. The cylinder castings, exhaust cavities and steam lines must be drained of all moisture and blown dry. Typical methods include: 1. Pressurize the boiler with compressed air with the locomotive stationary and NOTE: Methods “1” or “2” may have to be performed several times to discharge all of the moisture from the cylinders and steam pipes. If the locomotive is operated under air pressure, the air brake system should be made operational to provide safe stopping or other steps taken to control and stop the locomotive. Refer to the Section “Use of Compressed Air To Drain Locomotive Components” for additional information. l. Drain and wash tender water spaces. The tank should be inspected afterward and any remaining water removed by syphon or vacuum. When dry, spray the water space with outdoor paint or a commercial rust preventative. Drain and dry tender tank hoses and clean screens. m. On coal or wood burners, spray any exposed surfaces of the tender fuel space with outdoor paint or a commercial rust preventative. If the locomotive is to be stored outdoors for long term, remove all coal and spray the surfaces as above or cover the coal space with a tarp or a roof. n. On oil burners, drain and blow out all fuel lines, tank heater and blowback lines and the burner itself. Drain sludge and water 172 APPENDIX 3 — STEAM LOCOMOTIVE FIRETUBE BOILER INSPECTION AND REPAIR from the bottom of the fuel tank. Insure that tank hatches are secure and the tank is vented to prevent condensation. Draining the oil tank is recommended if the fuel oil is known to lose its volatile content during storage. headlight and marker and/or classification lights. Remove tools, radios and spare parts. Secure wood or metal covers over all windows and doors and board up the back of the cab. Secure all manholes on the top of the tender. o. After cleaning thoroughly, coat all side and main rods, cross heads, valve gear, guides, piston rods, brake pistons, feedwater pump pistons and air pump pistons with water-resistant grease or a rust preventative. Grease should be applied to the junction of each axle and driving box and journal box to prevent water entering. Grease should be applied to junction of rod and pin in valve gear and rods to prevent water entering. s. Inspect stored locomotives regularly for signs of rust, corrosion, damage, deterioration or vandalism and immediately take any corrective measures necessary. p. If the locomotive is moved after this is applied, it will be necessary to reapply the coating to piston rods and guides. NOTE: Heavy oil or unrefined oil such as any of the Bunker types (Bunker 6, etc.) should not be used for preservation of any components because the sulfur contained in it can accelerate corrosion. Standard motor oil or journal oil will not stick to and preserve wetted surfaces. All surfaces, to be so coated, must be dry. If moisture is a problem, steam cylinder oil should be applied. q. Plain journal bearings should be inspected for water and repacked. Roller bearing boxes should have all moisture drained and the boxes filled with lubricant. Grease plugs should be screwed down so that the threads are not exposed. r. If the locomotive is to be stored outdoors with questionable or no security, remove and store all cab gages, water glasses, lubricators, brass handles, seatboxes and any other items that thieves or vandals might attack. Remove the whistle, bell, 3-4050 USE OF COMPRESSED AIR TO DRAIN LOCOMOTIVE COMPONENTS The process of using air pressure to drain and empty auxiliary components such as the cylinders, superheater units and piping completely of water offers several advantages over other methods. The air compressor must be equipped with a suitable filter to enable it to supply oil-free air because the introduction of air that contains oil into the water/steam parts of the boiler and superheater will promote the formation of scale and water foaming when the locomotive is returned to service. The air compressor must be large enough size to provide the volume and pressure of air required. If the boiler is pressurized with compressed air, the air pressure must be raised slowly to prevent distorting or overstressing the firebox sheets or staybolts because the normal expansion of the boiler that occurs under steam pressure is not present when air pressure is used. Auxiliary components such as the stokers, air compressors, turbogenerators, power reverse are drained by pressurizing the boiler to between 1/2 to 3/4 of the rated boiler pressure 173 NATIONAL BOARD INSPECTION CODE with compressed air from the stationary air compressor then operating each component individually until the exhaust from it contains no moisture. When necessary, specific pipe lines can be drained by breaking the line at each end, attaching the air line to it directly then blowing the line out. 3-4060 Steam should be discharged through the cylinder cocks for several minutes to aid removal of any solvent, debris or rust that may have formed in the superheater units, steam pipes and dry pipe. All appliances should be tested under steam pressure before the locomotive is moved. RETURN TO SERVICE When returning a locomotive to service, the boiler, firebox and tender tank shall be ventilated to remove potentially hazardous atmosphere from the boiler interior before personnel enter it. In addition, the atmosphere in the boiler shall be verified to be safe for human occupancy before personnel enter it. For the boiler this can be accomplished by removing the washout plugs and placing a fan or air blower on top of the steam dome opening to force air into the boiler. For the firebox this can be accomplished by opening the smokebox door and firebox door and placing a fan or air blower at either location to force air through. Failure to do this could result in asphyxiation of the first personnel to enter the boiler or firebox. If possible, the locomotive should be moved into a heated engine house and the boiler allowed to warm up in the air for several days until it is the same temperature as the air. The initial fire up should be done slowly to allow even heating of the boiler. Before movement the cylinders should be warmed up by allowing a small quantity of steam to blow through them and out the cylinder cocks and exhaust passages. This is necessary to reduce the stress in the casting from thermal expansion of the metal. 174 Glossary of Terms Appendix 4 175 NATIONAL BOARD INSPECTION CODE APPENDIX 4 — GLOSSARY OF TERMS For the purpose of applying the rules of the NBIC, the following definitions of the terms used herein shall apply: inspection or examination for the purpose of process control or acceptance of materials or items. Address of Record (applicable to RA-2200) – Complete address of the company to which the National Board Certificate of Authorization is issued (shop facility). For field only certificates of authorization, the address from where the work is controlled. Authorized Inspection Agency – An Authorized Inspection Agency shall be either: Alteration – Any change in the item described on the original Manufacturer’s Data Report which affects the pressure containing capability of the pressure-retaining item. Non-physical changes such as an increase in the maximum allowable working pressure (internal or external), increase in design temperature, or a reduction in minimum temperature of a pressure-retaining item shall be considered an alteration. b. An insurance company which has been licensed or registered by the appropriate authority of a state of the United States or province of Canada to write boiler and pressure vessel insurance in such a state or province. ANSI – The American National Standards Institute ASME Code – The American Society of Mechanical Engineers’ Boiler and Pressure Vessel Code published by that Society, including addenda and Code Cases, approved by its council. Assembler (applicable to RA-2200) – An organization who purchases or receives from a manufacturer the necessary component parts of valves and assembles, adjusts, tests, seals and ships safety or safety relief valves at a geographical location and using facilities other than those used by the manufacturer. Audit (applicable to RA-2300) – A documented activity performed to verify by examination and evaluation of objective evidence that applicable elements of the quality program have been developed, documented, and implemented in accordance with specified requirements. An audit is separate from a. A jurisdictional authority as defined in the National Board Constitution; or Authorized Nuclear Inspection Agency (applicable to RA-2300) – An Authorized Inspection Agency which employs Authorized Nuclear Inspectors and provides nuclear inspection services in accordance with the NBIC and Section XI of the ASME Code. Authorized Nuclear Inspector (ANI) (applicable to RA-2300) – An Authorized Inspector employed by an Authorized Nuclear Inspection Agency, qualified in accordance with the National Board Rules for Commissioned Inspectors. Authorized Nuclear Repair Organization (applicable to RA-2300) – See “NR” Certificate Holder. Capacity Certification – The verification by the National Board that a particular valve design or model has successfully completed all capacity testing as required by the ASME Code. Conversion – The change of a pressure relief valve from one capacity-certified configuration to another by use of manufacturer ’s instructions. 176 APPENDIX 4 — GLOSSARY OF TERMS Critical Parts (applicable to RA-2200) – Critical Parts are those that may affect the valve flow passage, capacity, function or pressureretaining integrity. Lift Assist Device – A device used to apply an auxiliary load to a pressure relief valve stem or spindle, used to determine the valve set pressure as an alternative to a full pressure test. Demonstration – A program of making evident by illustration, explanation and completion of tasks documenting evaluation of an applicant’s ability to perform code activities including the adequacy of the applicant’s quality program and by a review of the implementation of that program at the address of record and/or work location. Manufacturer (applicable to RA-2200) – An organization holding an ASME Certificate of Authorization to apply the Code Symbol stamp responsible for design, material selection, capacity certification, manufacture of all component parts, assembly, testing, sealing, stamping and shipping of pressure relief valves. Field – A temporary location, under the control of the Certificate Holder, that is used for repairs and/or alterations to pressure-retaining items at an address different from that shown on the Certificate Holder’s Certificate of Authorization. Manufacturer’s Documentation – The documentation that includes technical information and certification required by the original code of construction. Field Repairs (applicable to RA-2200) – Field repairs are any repair conducted outside of the Certificate Holder’s fixed repair shop location. Field repairs may be conducted with the aid of mobile facilities with repair capabilities and with or without testing capabilities. Field repairs may be conducted in user facilities without the use of mobile facilities as described above, or in any other “VR” Certificate Holder’s fixed repair shop location. Inspector – See National Board Commissioned Inspector and National Board OwnerUser Commissioned Inspector. Jurisdiction – A governmental entity with the power, right or authority to interpret and enforce law, rules or ordinances pertaining to boilers, pressure vessels or other pressureretaining items. It includes National Board member jurisdictions defined as “jurisdictional authorities”. Jurisdictional Authority – A member of the National Board, as defined in the National Board Constitution. Modification (applicable to RA-2300) – Any change to an item which affects the existing design requirements. Modifications include nonphysical changes (such as an increase in the MAWP or design temperature, or a reduction in minimum temperature such that additional mechanical tests are required), design reconciliation and revision of design specifications, and the process of making physical changes to an item as required to meet revised design requirements. “NR” Certificate Holder – An organization in possession of a valid “NR” Certificate of Authorization issued by the National Board. NBIC – The National Board Inspection Code published by The National Board of Boiler and Pressure Vessel Inspectors. National Board – National Board of Boiler and Pressure Vessel Inspectors. National Board Commissioned Inspector – An individual who holds a valid and current National Board Commission. Nuclear Items – Items constructed in accordance with recognized standards to be used in nuclear power plants. 177 NATIONAL BOARD INSPECTION CODE Original Code of Construction – Documents promulgated by recognized national standards writing bodies that contain technical requirements for construction of pressureretaining items or equivalent to which the pressure-retaining item was certified by the original manufacturer. Owner (applicable to RA-2300) – The organization legally responsible for the operation, maintenance, safety, and power generation of the nuclear power plant, including the repair, modification, or replacement of items in the plant. Owner or User – As referenced in lower case letters means any person, firm or corporation legally responsible for the safe operation of any pressure-retaining item. Owner-User Inspection Organization – An owner or user of pressure-retaining items that maintains an established inspection program, whose organization and inspection procedures meet the requirements of the National Board rules and are acceptable to the jurisdiction or jurisdictional authority wherein the owner or user is located. Owner-User Inspector – An individual who holds a valid and current National Board Owner-User Commission. Pressure-retaining Items (PRI) – Any boiler, pressure vessel, piping, or material used for the containment of pressure, either internal or external. The pressure may be obtained from an external source, or by the application of heat from a direct source, or any combination thereof. Quality System (applicable to RA-2200 and RA-2300) – Those planned and systematic actions necessary to provide adequate confidence that items repaired, modified, or replaced are in accordance with the requirements of the NBIC and Section XI of the ASME Code. Repair (applicable to RA-2200 and Part RE) – Repair of a pressure relief valve is considered to be the replacement, remachining or cleaning of any critical part, lapping of the seat or disk or any other operation which may affect the pressure relief valve function or pressure-retaining integrity. Disassembly, reassembly and/or adjustments which affect the pressure relief valve function are also considered a repair. The initial installation, testing and adjustments of a new pressure relief valve on a boiler or pressure vessel are not considered a repair if made by the manufacturer or assembler of the valve. Repair – The work necessary to restore pressure-retaining items to a safe and satisfactory operating condition. Repair (applicable to RA-2300) – The process of restoring a component or system to a safe and satisfactory condition such that the existing design requirements are met. Replacement (applicable to RA-2300) – A type of repair completed by the fabrication and installation of spare or renewal components, appurtenances, and sub-assemblies, or parts of a component or system. Re-rating – See alteration. “R” Certificate Holder – An organization in possession of a valid “R” Certificate of Authorization issued by the National Board. Safety Relief Valves – A safety relief valve is a pressure relief valve characterized by rapid opening or pop action, or by opening in proportion to the increase in pressure over the opening pressure, depending on application. Shop – A permanent location, the address which is shown on the Certificate of Authorization, from which a Certificate Holder controls the repair and/or alteration of pressure-retaining items. 178 APPENDIX 4 — GLOSSARY OF TERMS Testing Laboratory – National Board accepted laboratory which performs functional and capacity tests of pressure relief devices. Unique Identifier (applicable to RA-2200) – Repair serial number, shop order number, etc., that appears on a valve repair nameplate such that traceability to the repair documentation is established. “VR” Certificate Holder – An organization in possession of a valid “VR” Certificate of Authorization issued by the National Board. 179 NATIONAL BOARD INSPECTION CODE 180 National Board Forms Appendix 5 181 NATIONAL BOARD INSPECTION CODE 182 APPENDIX 5 — NATIONAL BOARD FORMS FORM R-1 REPORT OF REPAIR in accordance with provisions of the National Board Inspection Code 1. 2. Work performed by Owner 1 2 (name of repair organization) (Form R No.) 53 (PO No., Job No., etc.) 3 (name) 4 (address) 4 3. Location of installation 4. Unit identification 5 5. Identifying nos.: 6. NBIC Edition/Addenda: (edition) 7 (name) (address) (boiler, pressure vessel) (mfg serial no.) 10 Original Code of Construction for Item: 8 8 8 9 (National Board No.) (jurisdiction No.) (other) (year built) 10 (addenda) 11 (name/section/division) Construction Code Used for Repair Performed: 55 6 Name of original manufacturer 11 (edition/addenda) 11 11 (name/section/division) Graphite Pressure Equipment (edition/addenda) 7. 8. Repair Type: Welded Description of work: 12 FRP Pressure Equipment 9. Pressure Test, if applied 13 psi MAWP 54 psi Replacement Parts. Attached are Manufacturer’s Partial Data Reports or Form R-3s properly completed for the following items of this report: (use supplemental sheet, Form R-4, if necessary) 14 (name of part, item number, data report type, mfg’s name, and identifying stamp) 10. Remarks: 15 CERTIFICATE OF COMPLIANCE 16 I, , certify that to the best of my knowledge and belief the statements in this report are correct and that all material, construction, and workmanship on this Repair conforms to the National Board Inspection Code. National Board “R” Certificate of Authorization No. 17 expires on 18 , 19 20 21 Date , Signed (name of repair organization) (authorized representative) CERTIFICATE OF INSPECTION 22 I, , holding a valid Commission issued by The National Board of Boiler and Pressure Vessel Inspectors and certificate of competency issued by the jurisdiction of 23 and employed by 24 of 25 have 26 , inspected the work described in this report on and state that to the best of my knowledge and belief this work complies with the applicable requirements of the National Board Inspection Code. By signing this certificate, neither the undersigned nor my employer makes any warranty, expressed or implied, concerning the work described in this report. Furthermore, neither the undersigned nor my employer shall be liable in any manner for any personal injury, property damage or loss of any kind arising from or connected with this inspection. 19 Date , Signed 27 Commissions 28 (inspector) (National Board and Jurisdiction No.) This form may be obtained from The National Board of Boiler and Pressure Vessel Inspectors, 1055 Crupper Ave., Columbus, OH 43229 183 NB-66 Rev. 10 NATIONAL BOARD INSPECTION CODE 184 APPENDIX 5 — NATIONAL BOARD FORMS FORM R-2 REPORT OF ALTERATION in accordance with provisions of the National Board Inspection Code 1 2 1a. Construction performed by ____________________________________________ _________________ (name of “R” organization responsible for construction) (Form “R” No.) 53 __________________________________________________________________________________________ (address) (PO No., Job No., etc.) 1 2 1b. Design performed by ___________________________________________________________________ (name of “R” organization responsible for design) (Form “R” No.) 53 __________________________________________________________________________________________ (address) (PO No., Job No., etc.) 3 2. Owner _________________________________________________________________________________ (name) __________________________________________________________________________________________ (address) 4 3. Location of installation ___________________________________________________________________ (name) __________________________________________________________________________________________ (address) 5 4.Unit identification ________________ (boiler, pressure vessel) 6 Name of original manufacturer _________________________ 7 8 8 8 9 5. Identifying nos.: ___________ __________________ _______________ ____________ ___________ (mfg serial no.) (National Board No.) (jurisdiction no.) 10 6. NBIC Edition/Addenda: ____________________________ (edition) (other) (year built) 10 ________________________________ 11 Original Code of Construction for Item: _____________________ (addenda) (name/section/division) 11 ___________________________ (edition/addenda) 11 Construction Code Used for Alteration Performed: ___________________ (name/section/division) 11 ____________________ (edition/addenda) 12 7a. Description of construction work: ________________________________________________________ (use supplemental sheet, Form R-4, if necessary) __________________________________________________________________________________________ __________________________________________________________________________________________ __________________________________________________________________________________________ __________________________________________________________________________________________ 12 7b. Description of design scope: _____________________________________________________________ (use supplemental sheet, Form R-4, if necessary) __________________________________________________________________________________________ __________________________________________________________________________________________ __________________________________________________________________________________________ Pressure Test, if applied 13 psi MAWP 54 psi 8. Replacement Parts. Attached are Manufacturer’s Partial Data Reports or Form R-3s properly completed for the following items of this report: 14 __________________________________________________________________________________________ (name of part, item number, data report type, mfg’s name, and identifying mark) __________________________________________________________________________________________ __________________________________________________________________________________________ __________________________________________________________________________________________ __________________________________________________________________________________________ __________________________________________________________________________________________ __________________________________________________________________________________________ __________________________________________________________________________________________ 9. Remarks: _______________________________________________________________________________ 15 __________________________________________________________________________________________ __________________________________________________________________________________________ __________________________________________________________________________________________ __________________________________________________________________________________________ __________________________________________________________________________________________ This form may be obtained from The National Board of Boiler and Pressure Vessel Inspectors, 1055 Crupper Ave., Columbus, OH 43229 185 NB-229 Rev.4 NATIONAL BOARD INSPECTION CODE 2 Form R-2 (back) (Form “R” No.) DESIGN CERTIFICATION I, 16 , certify that to the best of my knowledge and belief the statements in this report are correct and that the Design Change described in this report conforms to the National Board Inspection Code. 18 National Board “R” Certificate of Authorization No. 17 expires on , 20 Date 19 , Signed 21 (name of design organization) (authorized representative) CERTIFICATE OF DESIGN CHANGE REVIEW 22 I, , holding a valid Commission issued by The National Board of Boiler and Pressure Vessel Inspectors and certificate of competency issued by the jurisdiction of 23 and employed 24 25 by of have reviewed the design change as described in this report and state that to the best of my knowledge and belief such change complies with the applicable requirements of the National Board Inspection Code. By signing this certificate, neither the undersigned nor my employer makes any warranty, expressed or implied, concerning the work described in this report. Furthermore, neither the undersigned nor my employer shall be liable in any manner for any personal injury, property damage or loss of any kind arising from or connected with this inspection. Date 26 , Signed 27 Commissions 28 (inspector) (National Board and jurisdiction no.) CONSTRUCTION CERTIFICATION I, 16 , certify that to the best of my knowledge and belief the statements in this report are correct and that all material, construction, and workmanship on this Alteration conforms to the National Board Inspection Code. 18 , National Board “R” Certificate of Authorization No. 17 expires on 19 20 21 Date , Signed (name of construction organization) (authorized signature) CERTIFICATE OF INSPECTION 22 I, ,holding a valid Commission issued by The National Board of Boiler and Pressure Vessel Inspectors and certificate of competency issued by the jurisdiction of 23 and employed by 24 of 25 26 have inspected the work described in this report on , and state that to the best of my knowledge and belief this work complies with the applicable requirements of the National Board Inspection Code. By signing this certificate, neither the undersigned nor my employer makes any warranty, expressed or implied, concerning the work described in this report. Furthermore, neither the undersigned nor my employer shall be liable in any manner for any personal injury, property damage or loss of any kind arising from or connected with this inspection. Date 26 , Signed 27 Commissions 28 (inspector) (National Board and jurisdication no.) 186 APPENDIX 5 — NATIONAL BOARD FORMS FORM R-3 REPORT OF PARTS FABRICATED BY WELDING in accordance with provisions of the National Board Inspection Code 1. Manufactured by (address) 1 2 (name of manufacturer) (Form “R” No.) 53 (PO No., Job No., etc.) 2. Manufactured for 3. Design Condition specified by 4. Design Code 5. Identification of Parts 29 (name of purchaser) 32 30 (code type and section) 31 Code design by (name of organization) (name of organizations) 33 34 35 (code year) (addenda year) (formula on which MAWP is based) Name of Part Line Qty. No. Manufacturer’s Identifying No. Manufacturer’s Drawing No. Shop MAWP Hydro PSI Year Built 36 37 39 40 41 9 6. 38 13 Description of Parts (a) Connections other than tubes Heads or Ends (b) Tubes Line Size and No. Shape Material Thickness Thickness Material Diameter Thickness Material Spec. No. (in.) Shape (in.) Spec. No. (in.) (in.) Spec. No. 38 43 42 7. Remarks 44 45 46 43 47 48 43 15 This form may be obtained from The National Board of Boiler and Pressure Vessel Inspectors, 1055 Crupper Ave., Columbus, OH 43229 187 NB-230 Rev. 2 NATIONAL BOARD INSPECTION CODE 2 Form R-3 (back) (Form “R” No.) CERTIFICATE OF COMPLIANCE I, 16 , certify that to the best of my knowledge and belief the statements in this report are correct and that all material, fabrication, construction, and workmanship of the described parts conforms to the National Board Inspection Code and standards of construction cited. 17 18 , National Board “R” Certificate of Authorization No. expires on 19 20 21 Date , Signed (name of “R” Certificate Holder) (authorized representative) CERTIFICATE OF INSPECTION I, 22 ,holding a valid Commission issued by The National Board of Boiler and Pressure Vessel Inspectors and certificate of competency issued by the jurisdiction of 23 and 24 employed by of 25 26 have inspected the parts described in this report on , and state that to the best of my knowledge and belief the parts comply with the applicable requirements of the National Board Inspection Code. By signing this certificate, neither the undersigned nor my employer makes any warranty, expressed or implied, concerning the work described in this report. Furthermore, neither the undersigned nor my employer shall be liable in any manner for any personal injury, property damage or loss of any kind arising from or connected with this inspection. 26 27 Date , Signed Commissions 28 (inspector) (National Board and jurisdiction no.) 188 APPENDIX 5 — NATIONAL BOARD FORMS FORM R-4 REPORT SUPPLEMENTARY SHEET in accordance with provisions of the National Board Inspection Code 1. Work performed by (address) 3 or 29 1 49 2 (name) 49 (Form “R” referenced) 53 49 (PO No., Job No., etc.) 49 2. Owner 3. Location of installation (name) (address) (name) (address) Reference Line No. 51 Date 19 Date 19 Continued from Form R– 50 52 , Signed , Signed 21 (authorized representative) 21 Name 20 49 (authorized representative) Commissions (inspector) This form may be obtained from The National Board of Boiler and Pressure Vessel Inspectors, 1055 Crupper Ave., Columbus, OH 43229 189 20 49 (National Board and jurisdiction no.) NB-231 Rev. 2 NATIONAL BOARD INSPECTION CODE 190 APPENDIX 5 — NATIONAL BOARD FORMS GUIDE FOR COMPLETING NATIONAL BOARD FORM R REPORTS 1. Name and address of the “R” Certificate organization that performed the construction work (Line 1a) or the design (Line 1b). 2. For NBIC Report Forms registered with the National Board, indicate the sequential Form R Number assigned by the “R” Certificate organization that is registering the form; otherwise indicate “N/A”. For rerating only, the Design Organization registers the Form R-2. Where physical work is also performed, the Construction Organization registers the Form R-2. 3. Name and address of the Owner of the pressure retaining item. 4. Name and address of plant or facility where the pressure retaining item is installed. 5. Description of the pressure retaining item, such as boiler or pressure vessel. 6. Name of original manufacturer of the pressure retaining item if a boiler or pressure vessel. If other than a boiler or pressure vessel, complete if known. 7. Serial number of the pressure retaining item as assigned by the original manufacturer. 8. Identification of the pressure retaining item by applicable registration number. If installed in Canada, indicate the Canadian design registration number (CRN), and list the drawing number under “other.” 9. Identify the year in which fabrication/construction of the item was completed. 10. Indicate edition and addenda of the NBIC under which this work is being performed. 11. Indicate the name, section, division, edition, and addenda of the original code of construction for the pressure retaining item. Also indicate the name, section, division, edition, and addenda of the construction code used for the work being performed. If code cases are used, they shall be identified in the “Remarks” section. 12. State exact scope of work, and attach additional data, sketch, Form R-4, etc. as necessary. If additional data is attached, so state. 13. Indicate test pressure applied. 14. To be completed for all welded pressure components added during the work. Indicate part, item number, manufacturer’s name, stamped identification, and data report type. 15. Indicate any additional information pertaining to the work involved (e.g. routine repairs, code cases). For Form R-3 the part manufacturer is to indicate the extent he has performed any or all of the design function. If only a portion of the design, state which portion. 191 NATIONAL BOARD INSPECTION CODE 16. Type or print name of authorized representative of the “R” Certificate Holder. 17. Indicate National Board “R” Certificate or Authorization number. 18. Indicate month, day, and year that the “R” certificate expires. 19. Enter date certified. 20. Name of “R” Certificate organization that performed the identified work. 21. Signature of authorized representative. 22. Type or print name of Inspector. 23. Indicate Inspector’s jurisdiction. 24. Indicate Inspector’s employer. 25. Indicate address of Inspector’s employer (city and state or province). 26. Indicate month, day, and year of inspection by Inspector. In case of Routine Repairs this shall be the month, day and year the Inspector reviews the completed Routine Repair package. 27. Signature of Inspector. 28. National Board commission number of Inspector, jurisdiction, and certificate of competency numbers. 29. Name and address of organization that purchased the parts for incorporation into the repair or alteration, if known. If built for stock, so state. 30. Name of organization responsible for specifying the code design conditions. 31. Name of organization responsible for performing the code design, if known. 32. Name, section, and division of the design code, if known. 33. Indicate code edition year used for fabrication. 34. Indicate code addenda date used for fabrication. 35. Indicate code paragraph reference for formula used to establish the MAWP, if known. 36. Identify name of part, such as “superheater header.” 37. Indicate quantity of named parts. 38. Match line number references for identification of parts and description of parts. 192 APPENDIX 5 — NATIONAL BOARD FORMS 39. Indicate manufacturer’s serial number for the named part. 40. Indicate drawing number for the named part. 41. Indicate Maximum Allowable Working Pressure for the part, if known. 42. Use inside diameter for size; indicate shape as square, round, etc. 43. Indicate the complete material specification number and grade. 44. Indicate nominal thickness of plate and minimum thickness after forming. 45. Indicate shape as flat, dished, ellipsoidal, or hemispherical. 46. Indicate minimum thickness after forming. 47. Indicate outside diameter. 48. Indicate minimum thickness of tubes. 49. Complete information identical to that shown on the Form R to which this sheet is supplementary. 50. Indicate the Form R type. Example: Form R-1, Form R-2, Form R-3 51. Indicate the reference line number from the Form R to which this sheet is supplementary. 52. Complete information for which there was insufficient space on the reference Form R. 53. If applicable, purchase order, job number, etc. assigned by the organization performing the work. 54. Indicate the maximum allowable working pressure of the pressure-retaining item. 55. Indicate the type of repair, i.e., welded (RC-2000), graphite pressure equipment (Appendix 8), or fiber reinforced plastic pressure equipment (Appendix 9). 193 NATIONAL BOARD INSPECTION CODE 194 APPENDIX 5 — NATIONAL BOARD FORMS FORM NR–1 REPORT OF REPAIR MODIFICATION OR REPLACEMENT TO NUCLEAR COMPONENTS AND SYSTEMS IN NUCLEAR POWER PLANTS 1 1. Work performed by 2. Owner (address) 2 3 (name of NR certificate holder) (PO No., Job No., etc.) 5 (name) (address) 6 3. Name, address and identification of nuclear power plant 4. System 5a. Items Which Required Repair, Modification, or Replacement Activities 7 Identification Construction Code No. Type of Item Mfg. Name Mfg. Serial No. Nat’l Bd No. Juris. No. 1 9 10 12 13 16 Activitity Other Year Built Name/ Section/ Division Edition/ Addenda Code Case(s) Code Class Repair/ Mod/ Replace 17 18 19 20 20 20 21 2 3 4 5 6 7 8 9 10 11 12 5b. Items Installed During Replacement Activities Identification Construction Code Type of Item Installed or Replaced 5a Item No. Mfg. Name Mfg. Serial No. Nat’l Bd No. Juris. No. 9 22 23 24 25 26 Other Year Built Name/ Section/ Division Edition/ Addenda Code Case(s) Code Class 27 28 29 30 30 30 6. ASME Code Section XI applicable for inservice inspection: 31 7. 8. ASME Code Section XI used for repairs, modifications, or replacements: Construction Code used for repairs, modifications, or replacements: 33 9. Design responsibilities 34 10. Tests conducted: hydrostatic pneumatic design pressure 31 31 32 32 33 pressure 35 33 psi Code Case(s) 35 This form may be obtained from The National Board of Boiler and Pressure Vessel Inspectors, 1055 Crupper Ave., Columbus, OH 43229 195 32 NB-81 NATIONAL BOARD INSPECTION CODE 11. Description of work 12. Remarks 40 (use of properly identified additional sheet(s) or sketch(es) is acceptable) 41 CERTIFICATE OF COMPLIANCE 42 I, , certify that to the best of my knowledge and belief the statements made in this report are correct and the repair, modification or replacement activities described above conform to Section XI of the ASME Code and the National Board Inspection Code “NR” rules. 44 National Board Certificate of Authorization No. 43 to use the “NR stamp expires , 45 NR Certificate Holder 46 Date 49 , (name) Signed 47 48 (authorized representative) (title) CERTIFICATE OF INSPECTION I, , holding a valid commission issued by The National Board of Boiler and Pressure Vessel Inspectors and certificate of competency issued by the jurisdiction of 50 and employed by 51 of 52 53 have inspected the repair, modification or replacement described in this report on , and state that to the best of my knowledge and belief, this repair, modification or replacement activity has been completed in accordance with Section XI of the ASME Code and the National Board Inspection Code “NR” rules. By signing this certificate, neither the undersigned nor my employer makes any warranty, expressed or implied, concerning the work described in this report. Furthermore, neither the undersigned nor my employer shall be liable in any manner for any personal injury, property damage or a loss of any kind arising from or connected with this inspection. 46 Date , Signed 54 Commissions 55 (inspector) (National Board and jurisdiction no.) 196 APPENDIX 5 — NATIONAL BOARD FORMS GUIDE FOR COMPLETING NATIONAL BOARD FORM NR-1 AND NVR-1 REPORTS 1. Indicate whether the report is to cover repair, modification, or replacement activity. 2. Name and address of the organization, as shown on the Certificate of Authorization, which performed the repair, modification, or replacement activity. 3. Indicate the purchase order number, job number, etc., as applicable, assigned by the organization which performed the work. 4. Name and address of the organization for which the work was performed. 5. Name and address of the Owner of the nuclear power plant. 6. Name and address of the nuclear power plant and, if applicable, identification of the unit. 7. Identify the system (e.g. residual heat removal, reactor coolant, etc.) with which the repair, modification, or replacement activity is associated. 8. Describe the type of pressure relief device (e.g. safety valve, safety relief valve, pressure relief valve, etc.) 9. Indicate the type of component (e.g. vessel, line valve, pump, piping system, etc.) 10. Manufacturer’s name of the repaired, modified, or replaced item. 11. Indicate the pressure relief device by the manufacturer’s valve series or catalog number. 12. Manufacturer’s serial number of the repaired, modified, or replaced item. 13. National Board number, if applicable, of the repaired, modified, or replaced item. 14. Indicate the service as steam, liquid, gas, air, etc. 15. Indicate the pressure relief device by inlet size, in inches. 16. Indicate Jurisdiction number, if applicable, of the repaired, modified, or replaced item. 17. Indicate plant tag or identification number, if applicable, of the repaired, modified, or replaced item. 18. Year the repaired, modified, or replaced item was manufactured. 19. Identify the name, section, and division of the original construction Code for the repaired, modified, or replaced item. 197 NATIONAL BOARD INSPECTION CODE 20. Identify the edition, addenda, and as applicable, Code Cases and class of the original construction Code for the repaired, modified, or replaced item. 21. Indicate the activity performed on this item, i.e. repair, modification, or replacement. 22. Indicate the Item No. from Section 5a with which this replacement item is associated. Attach the Manufacturer’s Data Report, as applicable. 23. Manufacturer’s name of this replacement item. 24. Manufacturer’s serial number of this replacement item. 25. National Board number, if applicable, of this replacement item. 26. Jurisdictional number, if applicable, of this replacement item. 27. Plant tag or identification number of this replacement item. 28. Year this replacement item was manufactured. 29. Name, section, and division of the construction Code for this replacement item. 30. Edition, addenda, and as applicable, Code Cases and class of the construction Code for this replacement item. 31. Identify the edition, addenda, and any applicable Code cases of the ASME Section XI Code used for inservice inspection. 32. Identify the edition, addenda, and any applicable Code Cases of the ASME Section XI Code for the repair, modification, or replacement activity. 33. Identify the edition, addenda, and any applicable Code Cases of the construction Code for the repair, modification, or replacement activity. 34. Identify the organization responsible for design or design reconciliation, if applicable. 35. Identify the type of pressure test (i.e. hydrostatic, pneumatic, or design) and applied test pressure. Also indicate any Code Cases used in connection with the pressure test. 36. Indicate the set pressure of the valve. 37. Indicate blowdown, if applicable, as a percentage of set pressure. 38. Indicate the repair organization’s name and address. 39. Indicate the medium (steam, air, etc.) used for the adjustment of set pressure and, if applicable, blowdown. 198 APPENDIX 5 — NATIONAL BOARD FORMS 40. State exact scope of work for the repair, modification, or replacement activity. If necessary attach additional data, sketch, Form R-4, etc. If additional data is attached, so state. 41. Indicate any additional information pertaining to the work. 42. Type or print name of authorized representative from the certificate holder. 43. Indicate National Board Certificate of Authorization number. 44. Indicate month, day, and year the certificate expires. 45. Name of the certificate holder which performed the identified work. 46. Enter date certified. 47. Signature of authorized representative from the certificate holder. 48. Title of authorized representative. 49. Type or print name of Authorized Nuclear Inspector. 50. Indicate the jurisdiction where the work is performed. 51. Indicate Authorized Nuclear Inspector’s employer. 52. Indicate address of Authorized Nuclear Inspector’s employer (city and state or province). 53. Indicate month, day, and year of inspection by the Authorized Nuclear Inspector. 54. Signature of Authorized Nuclear Inspector. 55. National Board Commission number of the Authorized Nuclear Inspector, including endorsements, jurisdiction, and certificate of competency numbers. 199 NATIONAL BOARD INSPECTION CODE 200 APPENDIX 5 — NATIONAL BOARD FORMS FORM NVR–1 REPORT OF REPAIR MODIFICATION OR REPLACEMENT OF NUCLEAR PRESSURE RELIEF DEVICES 1. Work performed by (address) 2. Work performed for 3. Owner 1 2 3 (name of certificate holder) (PO No., Job No., etc.) 4 (name) 5 (name) (address) 4. Name, address and identification of nuclear power plant 5. a: Repaired pressure relief device: b: Name of manufacturer c: Identifying nos. 6 8 10 11 12 13 14 15 (type) (mfg’s serial no.) (Nat’l Bd no.) (service) (size) d: Construction Code 19 20 (name/section/division) (edition) 20 (edition) Construction Code used for repairs, modifications, or replacements: 9. Design responsibility 10. Opening pressure: made at: 34 36 Blowdown (if applicable) (Code Case(s)) 37 32 (addenda) (edition) (code class) 31 (Code Case(s)) 32 32 (addenda) (Code Case(s)) 33 33 33 (edition) (addenda) (Code Case(s)) %. Set pressure and blowdown adjustment 38 using 11. Description of work: (include name and identifying number of replacement parts) 12. Remarks: 20 31 7. ASME Code Section XI used for repairs, modifications, or replacements: 8. (year built) 20 (addenda) 31 6. ASME Code Section XI applicable for inservice inspection: 18 39 40 41 CERTIFICATE OF COMPLIANCE 42 I, , certify that to the best of my knowledge and belief the statements made in this report are correct and the repair, modification or replacement of the pressure relief devices described above conforms to Section XI of the ASME Code and the National Board Inspection Code “VR” and “NR” rules. 43 44 National Board Certificate of Authorization No. to use the “VR” stamp expires , 43 44 National Board Certificate of Authorization No. to use the “NR” stamp expires , Date 46 , 45 Signed 47 48 CERTIFICATE OF INSPECTION 49 I, , holding a valid commission issued by The National Board of Boiler and Pressure 50 Vessel Inspectors and certificate of competency issued by the jurisdiction of and 51 52 employed by of 53 have inspected the repair, modification or replacement described in this report on , and state that to the best of my knowledge and belief, this repair, modification or replacement has been completed in accordance with Section XI of the ASME Code and the National Board Inspection Code “VR” and “NR” rules. By signing this certificate, neither the undersigned nor my employer makes any warranty, expressed or implied, concerning the repair, modification or replacement described in this report. Furthermore, neither the undersigned nor my employer shall be liable in any manner for any personal injury, property damage or loss of any kind arising from or connected with this inspection. 46 54 55 Date , Signed Commissions (inspector) (National Board and jurisdiction no.) This form may be obtained from The National Board of Boiler and Pressure Vessel Inspectors, 1055 Crupper Ave., Columbus, OH 43229 201 NB-160 NATIONAL BOARD INSPECTION CODE 202 APPENDIX 5 — NATIONAL BOARD FORMS REPLACEMENT OF STAMPED DATA FORM in accordance with provisions of the National Board Inspection Code Submitted to Submitted by (name of jurisdiction) (name of owner.) (address) (address) (telephone no.) (telephone no.) 1. Manufactured by 2. Manufactured for 3. Location of installation 4. Date installed 5. Previously installed at 6. Manufacturer’s Data Report attached No Yes 7. Item registered with National Board No Yes, NB Number 8. Item identification Year built Type Dimensions Mfg. serial no. Jurisdiction no. MAWP 9. (name and address) (name and address) (address) psi Safety relief valve set at psi Complete the reverse side of this report with a true facsimile of the legible portion of the nameplate. 10. If nameplate is lost or illegible, documentation shall be attached identifying the object to the Manufacturer’s Data report referenced on this form. 11. I request authorization to replace the stamped data and/or nameplate on the above describe pressure-retaining item in accordance with the rules of the National Board Inspection Code (NBIC), Part RB-1030. Owner’s name Signature Date Title 12. Authorization is granted to replace the stamped data or to replace the nameplate of the above described pressure-retaining item. Signature Date (chief inspector or authorized representative) Jurisdiction This form may be obtained from The National Board of Boiler and Pressure Vessel Inspectors, 1055 Crupper Ave., Columbus, OH 43229 203 NB-136 Rev.5 NATIONAL BOARD INSPECTION CODE The following is a true facsimile of the legible portion of the item’s nameplate. (Please print. Where possible, also attach a rubbing of the nameplate.) I certify that to the best of my knowledge and belief, the statements in this report are correct, and that the replacement information, data, and identification numbers are correct and in accordance with provisions of the National Board Inspection Code, Part RB-1030. Attached is a facsimile or rubbing of the stamping or nameplate. Name of Original Manufacturer Signature Date (authorized representative) Certificate of Authorization No. Expires Witnessed by Employer Signature (name of inspector) (inspector) Date 204 Commissions APPENDIX 5 — NATIONAL BOARD FORMS FORM NB-4 NEW BUSINESS OR DISCONTINUANCE USED BY AUTHORIZED INSPECTION AGENCIES To: JURISDICTION 2. Notice of: New insurance business Discontinuance or cancellation Refusal to insure 5. OBJECT 6. OWNER’S NO. 1. DATE OF SERVICE 3. Effectve date 4. Type of object: High pressure boiler Low pressure boiler Pressure vessel 7. JURISDICTION NO. 8. NATIONALBOARD NO, 9. NAME OF MANUFACTURER 15. CERTIFICATE ISSUED Yes No 16. REASON FOR DISCONTINUANCE OR CANCELLATION Phys. condition Out of use Other 10. NAME OF OWNER 11. NAME OF OWNER INCLUDING COUNTY 12. LOCATION OF OBJECT INCLUDING COUNTY 13. USER OF OBJECT (IF SAME AS OWNER SHOW “SAME”) 14. DATE OF LAST CERTIFICATE INSPECT., IF ANY 17. REMARKS (USE REVERSE SIDE) 18. By: CHIEF INSPECTOR This form may be obtained from The National Board of Boiler and Pressure Vessel Inspectors, 1055 Crupper Ave., Columbus, OH 43229 205 BRANCH OFFICE NB-4 Rev. 2 NATIONAL BOARD INSPECTION CODE 206 APPENDIX 5 — NATIONAL BOARD FORMS FORM NB-5 BOILER OR PRESSURE VESSEL DATA REPORT FIRST INTERNAL INSPECTION Standard Form for Jurisdications Operating Under the ASME Code 1 DATE INSPECTED CERT EXP DATE MO | DAY | YEAR MO | YEAR CERTIFICATE POSTED Yes No OWNER NO. OWNER 2 JURISDICTION NUMBER NAT’L BD NO. NATURE OF BUSINESS KIND OF INSPECTION Int OWNER STREET ADDRESS OTHER NO. CERTIFICATE INSPECTION Yes Ext OWNERS CITY STATE USER’S NAME - OBJECT LOCATION SPECIFIC LOCATION IN PLANT OBJECT LOCATION - COUNTY USER’S STREET ADDRESS USER’S CITY STATE No ZIP NUMBER 3 ZIP NUMBER FT TYPE 4 8 10 11 12 13 WATER TANK YEAR BUILT MANUFACTURER Power Process Storage Heat Exchange Steam Htg HWH HWS FUEL (BOILER) Prev. Inspection Set at HYDRO TEST No (If no, explain fully on back of form - listing code violation) SHELL DIAMETER No. in. ALLOWABLE STRESS ID OVERALL LENGTH OD ft. Thks in Sq Ft Double Thickness Welded HEAD THICKNESS Brazed HEAD TYPE in. Plus TUBE SHEET THICKNESS Minus Movable Flat Quick Opening in. Dia. in. FIRE TUBE DISTANCE UPPER TUBES TO SHELL RADIUS DISH BOILERS Front Length in. Rear Rear No. in. 17 18 19 20 21 22 23 Welded Above Tubes { Below Tubes Diagonal Welded Diagonal Drilled (Size Hole Size Welded Front Weldless Yes No FEED PIPE Yes in. OUTLETS Btu/Hr No. Yes Steam WATER GAGE GLASS TRY COOKS BLOWOFF PIPE No. No. Size Motor in. Location in. Riveted Seamless NET AREA in. X in. sq. in. Size Yes No (If no, explain on back of form) STEAM LINES PROPERLY DRAINED Yes No (If no, explain on back of form) CHECK FEED LINE VALVES Yes Yes SECTIONS Width Welded RETURN LINE No Yes No INSPECTION OPENINGS COMPLY WTH CODE CAST-IRON BOILERS in. in. PROPERLY DRAINED No TYPE DRIVE No. ft. Rear TYPE LONG. SEAM PITCH in. Cfm OTHER CONNECTIONS No FEED APPLIANCES Rear Front TOTAL LENGTH in. in.) Lb/Hr ON RETURN LINES { Below Tubes REAR HEAD Weldless Other TOTAL CAPACITY ON STEAM LINE % Above Tubes AREA OF STAYS Plain Hollow LIGAMENT EFF in. AREA OF STAYS Head to Head Corrugated % in. Material in. X DIAMETER Size Dia. in. THICKNESS VALVES Length No. FRONT HEAD Head to Head Rear No. SAFETY-RELIEF VALVES in. BOLTING TYPE .) Other in. X TYPE Adamson (No. Sect No. ELLIP RATIO ft. STAYBOLTS - TYPE STOP in. X in. FURNACE - TYPE 16 Wtr Wall SEAM EFF in. STAYED AREA STAYS ABOVE TUBES Threaded Sinuous PITCH (WT BLRS) No. Front No. ASME Spec Nos PITCH TUBES Front No. 15 Box Dia Hole Fixed No TYPE in. Rivited Date MATERIAL in. HEADERS - WT BOILERS RIVITED Butt psi TOTAL HTG SURFACE (BOILER) Single TYPE LONGITUDINAL SEAM Lap Yes THICKNESS in. BUTT STRAP psi No EXPLAIN IF PRESSURE CHANGED IS CONDITION OF OBJECT SUCH THAT A CERTIFICATE MAY BE ISSUED? Yes PRESSURE GAGE TESTED Yes SAFETY-RELIEF VALVES PRESSURE This Inspection METHOD OF FIRING (BOILER) Other STAYS BELOWTUBES 14 YEAR INST Height in. No. Yes SHOW ALL CODE STAMPING ON BACK OF FORM. Give details (use sketch) for No (If no, explain on back of form) DOES WELDING ON STEAM, FEED BLOWOFF AND OTHER PIPING COMPLY WITH CODE No (If no, explain on back of form) DOES ALL MATERIAL OTHER THAN AS INDICATED ABOVE COMPLY WITH CODE special objects NOT covered above - such as Double wall vessels etc. Yes No (If no, explain on back of form) NAME AND TITLE OF PERSON TO WHOM REQUIREMENTS WERE EXPLAINED: I HEREBY CERTIFY THIS IS A TRUE REPORT OF MY INSPECTION Signature of Inspector IDENT NO. EMPLOYED BY This form may be obtained from The National Board of Boiler and Pressure Vessel Inspectors, 1055 Crupper Ave., Columbus, OH 43229 207 IDENT NO. NB-5 Rev. 0 Complete When Not Registered National Board Complete When Not Registered National Board 9 AIR TANK New Second Hand USE 7 CI Other 5 6 WT NATIONAL BOARD INSPECTION CODE OTHER CONDITIONS AND REQUIREMENTS CODE STAMPING (BACK) 208 APPENDIX 5 — NATIONAL BOARD FORMS FORM NB-6 BOILER-FIRED PRESSURE VESSEL REPORT OF INSPECTION Standard Form for Jurisdications Operating Under the ASME Code 1 DATE INSPECTED CERT EXP DATE MO | DAY | YEAR MO | YEAR CERTIFICATE POSTED Yes No OWNER NO. OWNER JURISDICTION NUMBER NAT’L BD NO. NATURE OF BUSINESS KIND OF INSPECTION 2 Int OWNER STREET ADDRESS Ext OTHER NO. CERTIFICATE INSPECTION Yes OWNERS CITY STATE USER’S NAME - OBJECT LOCATION SPECIFIC LOCATION IN PLANT OBJECT LOCATION - COUNTY USER’S STREET ADDRESS USER’S CITY STATE No ZIP NUMBER 3 ZIP NUMBER 4 YEAR BUILT TYPE FT WT MANUFACTURER Other FUEL 5 USE 6 PRESSURE ALLOWED 7 CI Power Process Steam Htg HWH HWS This Inspection Prev. Inspection PRESSURE GAGE TESTED Yes SAFETY-RELIEF VALVES Set at No HEATING SURFACE OR BTU Total Capacity IS CONDITION OF OBJECT SUCH THAT A CERTIFICATE MAY BE ISSUED? Yes METHOD OF FIRING Other HYDRO TEST No (If no, explain fully under conditions) Yes psi Date No With respect to the internal surface, describe and state locat 8 CONDITIONS: location and extent of any erosion, grooving, bulging, warping, c ends, coils, nipples, etc. Describe any adverse conditions baffles, supports, etc. Describe any major changes or repairs made since last inspection. 9 10 REQUIREMENTS: (List Code Violations) NAME AND TITLE OF PERSON TO WHOM REQUIREMENTS WERE EXPLAINED: I HEREBY CERTIFY THIS IS A TRUE REPORT OF MY INSPECTION SIGNATURE OF INSPECTOR IDENT NO. EMPLOYED BY This form may be obtained from The National Board of Boiler and Pressure Vessel Inspectors, 1055 Crupper Ave., Columbus, OH 43229 209 IDENT NO. NB-6 Rev. 3 NATIONAL BOARD INSPECTION CODE 210 APPENDIX 5 — NATIONAL BOARD FORMS FORM NB-7 PRESSURE VESSELS REPORT OF INSPECTION Standard Form for Jurisdications Operating Under the ASME Code 1 DATE INSPECTED CERT EXP DATE MO | DAY | YEAR MO | YEAR CERTIFICATE POSTED Yes No OWNER NO. OWNER JURISDICTION NUMBER NAT’L BD NO. NATURE OF BUSINESS KIND OF INSPECTION 2 Int OWNER STREET ADDRESS Ext OTHER NO. CERTIFICATE INSPECTION Yes OWNERS CITY STATE USER’S NAME - OBJECT LOCATION SPECIFIC LOCATION IN PLANT OBJECT LOCATION - COUNTY USER’S STREET ADDRESS USER’S CITY STATE No ZIP NUMBER 3 ZIP NUMBER 4 YEAR BUILT TYPE AIR TANK WATER TANK SIZE 5 USE 6 PRESSURE ALLOWED 7 MANUFACTURER Other Storage Process Heat Exchange Yes SAFETY-RELIEF VALVES This Inspection Prev. Inspection No EXPLAIN IF PRESSURE CHANGED Set at Total Capacity IS CONDITION OF OBJECT SUCH THAT A CERTIFICATE MAY BE ISSUED? Yes PRESSURE GAGE TESTED Other HYDRO TEST No (If no, explain fully under conditions) Yes psi Date No With respect to the internal surface, describe and state locat 8 CONDITIONS: location and extent of any erosion, grooving, bulging, warping, c ends, coils, nipples, etc. Describe any adverse conditions baffles, supports, etc. Describe any major changes or repairs made since last inspection. 9 10 REQUIREMENTS: (List Code Violations) NAME AND TITLE OF PERSON TO WHOM REQUIREMENTS WERE EXPLAINED: I HEREBY CERTIFY THIS IS A TRUE REPORT OF MY INSPECTION SIGNATURE OF INSPECTOR IDENT NO. EMPLOYED BY This form may be obtained from The National Board of Boiler and Pressure Vessel Inspectors, 1055 Crupper Ave., Columbus, OH 43229 211 IDENT NO. NB-7 Rev. 0 NATIONAL BOARD INSPECTION CODE PRESSURE VESSEL — REPORT OF INSPECTION — (EXTENSION SHEET) DATE OF INSPECTED OWNER’S NO. JURISDICTION NUMBER OWNER-USER N.B. ASME OR STD. NO. INT LOCATION EXT *CERT – NO. OF YEARS TYPE OF OBJECT YEAR BUILT MADE BY * In this column show the number of years for which the inspector authorizes the issuance of the certificate. 212 ALLOW. PRESS. TEMP OF R.V.S.V. SETTING Examples of Repairs and Alterations Appendix 6 213 NATIONAL BOARD INSPECTION CODE APPENDIX 6 — EXAMPLES OF REPAIRS AND ALTERATIONS 6-1000 f. INTRODUCTION The purpose of this appendix is to provide owners, users, repair organizations and Inspectors with assistance in evaluating whether contemplated work on a pressure retaining item should be categorized as a repair or alteration. The significance of this categorization affects the qualifications of the organization performing the work as well as the resultant documentation. 6-2000 g. in a boiler, a change in the arrangement of tubes in furnace walls, economizer or super heater sections; h. replacement of pressure retaining parts identical to those existing on the pressure retaining item and described on the original Manufacturer’s Data Report. For example: 1. replacement of furnace floor tubes and/or sidewall tubes in a boiler EXAMPLES OF REPAIRS Repairs are defined in the Glossary. Examples of repairs are: 2. replacement of a shell or head in accordance with the original design a. weld repairs or replacement of pressure parts or attachments that have failed in a weld or in the base material; 3. rewelding a circumferential or longitudinal seam in a shell or head 4. replacement of nozzles of a size where reinforcement is not a consideration b. the addition of welded attachments to pressure parts, such as: 1. studs for insulation or refractory lining i. installation of new nozzles or openings of such a size and connection type that A04 reinforcement and strength calculations are not a consideration required by the original code of construction; j. the addition of a nozzle where reinforcement is a consideration may be considered to be a repair provided the nozzle is identical to one in the original design, located in a similar part of the vessel, and not closer than three times its diameter from another nozzle. The addition of such a nozzle shall be restricted by any service requirements; 2. hex steel or expanded metal for refractory lining 3. ladder clips 4. brackets, having loadings which do not affect the design of the pressure retaining item to which they are attached 5. tray support rings c. corrosion resistant strip lining or weld overlay; d. weld buildup of wasted areas; e. replacement of heat exchanger tube sheets in accordance with the original design; replacement of boiler and heat exchanger tubes where welding is involved; k. the installation of a flush patch to a pressure-retaining item; l. 214 the replacement of a shell course in a cylindrical pressure vessel; APPENDIX 6 — EXAMPLES OF REPAIRS AND ALTERATIONS m. welding of gage holes; temperature of a pressure retaining item regardless of whether or not a physical change was made to the pressure retaining item; n. welding of wasted or distorted flange faces; o. replacement of slip-on flanges with weld neck flanges or vice-versa; p. seal welding of buttstraps and rivets; q. subject to the administrative procedures of the jurisdiction and approval of the Inspector, the replacement of a riveted section or part by welding; r. the repair or replacement of a pressure part with a Code accepted material that has a nominal composition and strength that is equivalent to the original material, and is suitable for the intended service; s. replacement of a pressure retaining part with a material of different nominal composition, equal to or greater in allowable stress from that used in the original design, provided the replacement material satisfies the material and design requirements of the original code of construction under which the vessel was built. 6-3000 EXAMPLES OF ALTERATIONS b. a decrease in the minimum temperature; c. the addition of new nozzles or openings in a boiler or pressure vessel except those classified as repairs; d. a change in the dimensions or contour of a pressure-retaining item; e. in a boiler, an increase in the heating surface or steaming capacity such that an increase in the relieving capacity is required; f. the addition of a pressurized jacket to a pressure vessel; g. except as permitted in 6-2000(s), replacement of a pressure-retaining part in a pressure-retaining item with a material of different allowable stress or nominal composition from that used in the original design. h. The addition of a bracket or an increase in loading on an existing bracket which affects the design of the pressure-retaining item to which it is attached. Alterations are defined in the Glossary. Examples are: a. an increase in the maximum allowable working pressure (internal or external) or 215 NATIONAL BOARD INSPECTION CODE 216 Procedures to Extend the “VR” Certificate of Authorization Stamp to ASME “NV” Stamped Pressure Relief Devices Appendix 7 217 NATIONAL BOARD INSPECTION CODE APPENDIX 7 — PROCEDURES TO EXTEND THE “VR” CERTIFICATE OF AUTHORIZATION AND STAMP TO ASME “NV” STAMPED PRESSURE RELIEF DEVICES 7-1000 jurisdiction wherein the applicant’s repair facilities are located, and the applicant’s Authorized Inspection Agency. Further verification of such implementation by the survey team may not be necessary if the applicant holds a valid ASME “NV” certificate and can verify by documentation the capability of implementing the quality assurance program for repair of “NV” stamped pressure relief devices, covered by the applicant’s ASME “NV” certificate. INTRODUCTION Approval to extend the scope of the National Board “VR” Certificate of Authorization to the Certificate Holder to use the “VR” stamp on ASME Code “NV” Class 1, 2 or 3 stamped pressure relief devices, which have been capacity certified by the National Board, may be given subject to the following provisions: 7-2000 ADMINISTRATIVE PROCEDURES The repair organization shall hold a valid “VR” Certificate of Authorization. The repair organization shall obtain a National Board “NR” Certificate of Authorization and stamp to repair, modify or replace nuclear components. The requirements for said certificate and stamp include, but are not limited to, the following. The repair organization shall: a. Maintain a documented quality assurance program which meets the applicable requirements of RA-2300 of the NBIC. This program shall also include all the applicable requirements for the use of the “VR” stamp; b. Have a contract or agreement with an Inspection Agency to provide inspection of repaired “NV” stamped pressure relief devices by Inspectors who have been qualified in accordance with the requirements of ASME QAI-1, Qualifications for Authorized Inspection; c. Successfully complete a survey of the quality assurance program and its implementation. This survey shall be conducted by representatives of the National Board, the The application of the “NR” Certificate of Authorization and stamp shall clearly define the scope of intended activities with respect to the repair of Section III “NV” stamped pressure relief devices. Revisions to the quality assurance pro-gram shall be acceptable to the Authorized Nuclear Inspector Supervisor and the National Board before being implemented. Endorsement of the “VR” Certificate of Authorization for the repair of “NV” stamped pressure relief devices shall be granted upon acceptance by the National Board Accreditation Committee on Nuclear Repair, Modification and Replacement. Verification testing of valves repaired by the applicant shall not be required provided such testing has been successfully completed under the applicant’s “VR” certification program. Asurvey of the applicant for the “VR” Certificate of Authorization and endorsement of the repair of “NV” stamped pressure relief devices may be made concurrently. 218 APPENDIX 7 — PROCEDURES TO EXTEND THE “VR” CERTIFICATE OF AUTHORIZATION STAMP TO ASME “NV” STAMPED PRESSURE RELIEF DEVICES 7-3000 GENERAL RULES ASME Code Section III “NV” stamped pressure relief devices, which have been repaired in accordance with these rules, shall be stamped with both the “VR” and “NR” stamps. The “VR” and “NR” stamps shall be applied only to “NV” stamped (Class 1, 2 or 3) National Board capacity certified pressure relief devices which have been disassembled, inspected and repaired as necessary, such that the valves’ condition and performance are equivalent to the standards for new valves. All measuring and test equipment used in the repair of pressure relief devices shall be calibrated against certified equipment having known valid relationships to nationally recognized standards. Documentation of the repair of “NV” stamped pressure relief devices shall be recorded on the National Board Form NVR-1, Report of Repair, Modification or Replacement of Nuclear Pressure Relief Devices in accordance with the requirements of RA-2300 of the NBIC. When an ASME “NV” Stamped Pressure Relief Device requires a duplicate nameplate because the original nameplate is illegible or missing, it may be applied using the procedures of RE-1064 provided concurrence is obtained from the Authorized Nuclear Inspector and jurisdiction. In this case the nameplate shall be marked “SEC. III” to indicate the original ASME Code stamping. 219 NATIONAL BOARD INSPECTION CODE 220 Inspection, Repair and Alteration of Graphite Pressure Equipment Appendix 8 221 NATIONAL BOARD INSPECTION CODE APPENDIX 8 — INSPECTION, REPAIR AND ALTERATION OF GRAPHITE PRESSURE EQUIPMENT 8-1000 SCOPE a. The purpose of this Appendix is to provide requirements for inservice inspection, repair, and alteration of pressure equipment manufactured from impervious graphite materials. b. Repair or alteration of metallic components shall comply with Part RC. c. The impervious graphite (carbon, graphite, or graphite compound) used for the construction of graphite pressure vessels is a composite material, consisting of “raw” carbon or graphite which is impregnated with a resin using a tightly controlled pressure/heat cycle(s). The interaction between the raw material and the resin is the determining factor when considering the design characteristics of the material. The design characteristics include the strengths (flexural, compressive, and tensile), permeability, coefficient of thermal expansion, thermal conductivity, and ultimately, the safe operating life of the vessel. d. The process used in the manufacturing of the raw material is well documented. The expertise developed in this field allows for many different grades to be manufactured to meet the specific needs of various industries, including corrosive chemical processing pressure vessels. In the chemical processing industry the properties of the raw material are dictated by the Manufacturer of the impregnated material, based on the pressure/temperature cycle and the type of resin used for impregnation. The raw material requirements are defined and communicated to the manufacturer of the raw material. The cycle and resin type may vary from Manufacturer to Manufacturer, and also for each “grade” of impregnated material a Manufacturer produces. e. Repairs to graphite pressure equipment require the use of certified impregnated graphite and cement. The determining factor in establishing the desired material properties is the resin impregnation cycle. If the resin impregnation cycle is not controlled, it is not possible to meet the minimum design values. f. With over a century of experience with graphite pressure equipment, the essential variables of the process have been defined and apply universally to all Manufacturers of impervious graphite equipment. Therefore, by requiring the essential variables of the resin impregnation cycle to be identified and verified, it is possible to assign a “lot” number to all certified materials at completion of the resin impregnation process. This can be done with the assurance of meaningful and consistent test results. 8-1010 APPLICATION Due to inherent resistance to chemical attack, graphite pressure equipment is often used in corrosive applications, which may include lethal service. 8-1020 OPERATIONS The owner should maintain controlled conditions for use of graphite pressure equipment, including the use of temperature and pressure recorders and/or operating logs. The owner should maintain operating procedures, and ensure that pressure and temperature are controlled. A thermal or pressure spike may damage the graphite or metal components. 222 APPENDIX 8 — INSPECTION, REPAIR, AND ALTERATION OF GRAPHITE PRESSURE EQUIPMENT 8-2000 INSERVICE INSPECTION The guidelines provided in Part RB shall apply to graphite pressure equipment, except as modified herein. a. Graphite pressure vessels, pressure parts, and vessel components should receive an external visual examination biennially. All accessible surfaces should be chemically cleaned. Cleaning fluids containing strong oxidants should not be used. b. Typical indicators which may necessitate graphite pressure equipment inspection, evaluation, and repair include: 1. Cross contamination of either process or service fluids 2. External leakage is observed 3. Flow rate is reduced or excessive pressure drop is observed 4. Heat transfer performance is reduced c. Cracks, bulges, blisters, delaminations, spalling conditions, and excessive erosion are cause for repair or replacement. Any surface discoloration should be re-cleaned and examined more closely to determine if a delamination or spalling condition exists. d. Other typical discontinuities include chipping, erosion, baffle cutting due to vibration, and cement deterioration. All passage ways are susceptible to fouling. 8-3000 REPAIRS The requirements provided in Part RC-1020(i), RC-1060, RC-1070, RC-1110, RC-1120, RC1140, RC-1141, RC-2020, RC-2030 and RC2031 except (a) shall apply, insofar as they are applicable to graphite pressure equipment. Graphite specific requirements include: a. Organizations performing repairs shall be accredited as described in Part RA, as appropriate for the scope of work to be performed. b. When the standard governing the original construction is not the ASME Code, repairs or alterations shall conform to the edition of the original construction standard or specification most applicable to the work. Where the original code of construction is unknown, the edition and addenda of the ASME Code most appropriate for the work shall be used, provided the “R” Certificate Holder has the concurrence of the Inspector and the jurisdiction where the pressure-retaining item is installed. c. The materials used in making repairs or alterations shall conform to the requirements of the original code of construction except as provided in subparagraph (j). The “R” Certificate Holder is responsible for verifying identification of existing materials from original data, drawings, or unit records and identification of the materials to be installed. d. When ASME is the original code of construction, replacement parts subject to internal or external pressure, which require shop inspection by an Authorized Inspector, shall be fabricated by an organization having an appropriate ASME Certificate of Authorization. The item shall be inspected and stamped as required by the applicable section of the ASME Code. A completed ASME Manufacturer’s Partial Data Report shall be supplied by the manufacturer. e. When the original code of construction is other than ASME, replacement parts subject to internal or external pressure shall be manufactured by an organization certified as required by the original code of 223 NATIONAL BOARD INSPECTION CODE construction. The item shall be inspected and stamped as required by the original code of construction. Certification to the original code of construction as required by the original code of construction or equivalent shall be supplied with the item. When this is not possible or practicable, the organization fabricating the part may have a National Board Certificate of Authorization; replacement parts shall be documented on Form R-3 and the “R” symbol stamp applied as described in Appendix 2. f. h. Pressure-retaining items repaired in accordance with the NBIC shall be marked as required by Appendix 2. The letter “G” shall be applied to the nameplate under the “R” stamp when graphite repairs are made. The procedure defined in 8-6000 may be used in lieu of the stamping and nameplate attachment requirements of Appendix 2. Graphite parts which have previously been in service in one pressure vessel should not be used in a second vessel without prior approval of the owner. Consideration should be given to the service condition of the previous process and possible contamination of the subsequent process. k. Blind cracks and delaminations may not be repaired by cement injection only. l. Organizations performing repairs under an “R” stamp program shall register such repairs with the National Board. g. Before signing the appropriate NBIC Form, the Inspector shall review the drawings, witness any required pressure test, assure that the required nondestructive examinations have been performed satisfactorily, and that the other functions necessary to assure compliance with the requirement of this Code have been performed. i. j. Cracks and porosity in tubes may not be repaired. Cracked and porous sections may be removed so that the remainder of the tube may be used. Individual tube sections shall not be less than 24 in. (600 mm) in length, and the number of segments in a tube shall not exceed the quantity listed in Table 8-3000. m. Cementing procedure specifications shall be qualified by the repair organization. The specifications shall be qualified as required by the code of construction. Cementing procedure qualification shall be verified by the Inspector. Legible copies of the completed Form R-1, together with attachments, shall be distributed to the owner or user, the Inspector, the jurisdiction if required, and the Authorized Inspection Agency responsible for inservice inspection. Form R-1 shall be registered with the National Board. Distribution of Form R-1 and attachments shall be the responsibility of the organization performing the repair. 224 TABLE 8-3000 — Permitted Quantity of Tube Segments Total Tube Length, ft. (m) 6 (1.8) 9 (2.7) 12 (3.7) 14 (4.3) 16 (4.9) 18 (5.5) 20 (6.1) 22 (6.7) 24 (7.3) 27 (8.3) Number of Number Tube Segments of Joints 1 0 2 1 3 2 3 2 4 3 4 3 4 3 4 3 5 4 5 4 APPENDIX 8 — INSPECTION, REPAIR, AND ALTERATION OF GRAPHITE PRESSURE EQUIPMENT n. Cementing technicians shall be qualified by the repair organization. The technicians shall be qualified as required by the code of construction. A cementing technician is any individual who is responsible for proper joint preparation, cleaning parts to be joined, mixing cement, applying cement, securing the joint during the curing process, and controlling the curing process. c. Replacing Individual Tubes — drilling out and replacing tubes with new tubes or repaired tubes. Only certified materials shall be used for this repair. o. All records shall be made available to the Inspector. e. Plugging Tubes — plugging individual tubes using accepted procedures. p. Completed repairs shall be subjected to a pressure test. The test pressure shall not be less than the maximum allowable working pressure or twice the operating pressure, whichever is lower. The hydrostatic test pressure shall be maintained for 30 minutes. f. q. Reimpregnation may be used to enhance the performance and extend the life of graphite components. Reimpregnation of graphite shall not be considered a means to restore original strength, nor shall it be considered a means to restore the original depth of impregnation. 8-3010 REPAIRS OF A ROUTINE NATURE The following repairs shall be considered routine, and shall comply with RC-2031. a. Machining — routine repair shall not include the machining of pressure retaining parts with the exception of minor machining for cleaning and joint preparation not to exceed 1/32 in. (0.8 mm) of material thickness. b. Repair of Gasket Sufaces — remachining of gasket surfaces, reserrating, or flattening is permitted if the design thickness is maintained. d. Nozzle Replacement — replacement of nozzles by removing the old nozzle and cementing a new nozzle in place. This is applicable for nozzles with inside diameters not exceeding 18 in. (450 mm). Surface Repair — surface repair by installation of plugs or inlay material shall not exceed 1 cu. in. (16 cu. cm) of total volume. Connected repairs are not to be considered routine. g. Replacement or Addition of Non-Load Bearing Attachments to Pressure-Retaining Item — For attachment of non-load bearing attachments to pressure-retaining items, the cementing procedure specification need only be qualified for the pressure part and cement to be used. Complete records of these routine repairs shall be kept for review by the Inspector. The records shall include the number of tubes replaced or plugged and their location within the tube bundle. 8-4000 ALTERATIONS The requirements provided in Part RC-3010, RC-3020, RC-3050, RC-3051, and RC-3052 shall apply, insofar as they are applicable to the materials discussed herein. Completed alterations shall be subjected to a pressure test not less than that required by the code of construction. The hydrostatic test pressure shall be maintained for a minimum of 30 minutes. The pressure shall be reduced to MAWP and maintained for inspection. 225 NATIONAL BOARD INSPECTION CODE The nameplate shall be applied in accordance with Appendix 2. The letter “G” shall be applied to the nameplate under the “R” stamp when graphite alterations are made. The procedure defined in 8-6000 may be used in lieu of the stamping and nameplate attachment requirements of Appendix 2. Organizations performing alterations under an “R” stamp program shall register such alterations with the National Board. 8-5000 REPAIR GUIDE FOR IMPERVIOUS GRAPHITE 8-5010 INTRODUCTION (See Figures 8-5010-a thru f) which leaks. All surfaces should be neutralized to a pH of 7. Graphite parts should be cleaned and washed with acetone to remove all moisture. All damage should be examined and evaluated to determine the cause. Identification and elimination of the cause is essential in helping to prevent a recurrence. An acetone wash on the surface of the damaged part is useful in identifying the full extent of the cracks. The acetone will quickly evaporate from the surface, leaving the cracks damp and clearly visible. This section is intended to provide suggested process and technique details for repairs. This section is nonmandatory, but should be used as a guide by the repair organization in developing specific repair procedures. Damage to domes (heads), tubesheets, or nozzles is invariably a sign of improper installation, operation, or maintenance. Because such damage is random in nature, each case must be analyzed separately to determine the appropriate repair procedure, and the economics of repair versus replacement. Impervious graphite is a machinable material. Parts can be modified or repaired in the field, or in a repair shop. Machining operations may be handled with high-speed steel tools. Extensive machining requires tungsten carbide or diamond tooling. No cooling or flushing fluid is required, nor should either be used. Cleanliness is important. Dusty, dirty, and chemically contaminated surfaces prevent proper cement adhesion. Poor cement adhesion will result in a low strength joint or a joint 226 FIGURE 8-5010-a — Typical tubetubesheet joints APPENDIX 8 — INSPECTION, REPAIR, AND ALTERATION OF GRAPHITE PRESSURE EQUIPMENT FIGURE 8-5010-e — Typical edge repair material inlay FIGURE 8-5010-b — Typical tube replacement using sleeve and insert at tubesheet joint. FIGURE 8-5010-c — Typical Tube Replacement Using Sleeve at Tubesheet Joint FIGURE 8-5010-f — Typical nozzle connection �� FIGURE 8-5010-d — Typical tube-tube joints 8-5020 TYPICAL GRAPHITE FRACTURES 8-5021 MAJOR FRACTURE An extensive fracture, such as shown in Figure 8-5021, is best repaired by completing the break and re-cementing the two pieces. Temporary steel banding around the circumference is a method of clamping the repair until the cement is cured. 8-5022 INTERMEDIATE FRACTURE The break is too minor to warrant completing the fracture. A pie-shaped cut may be made and the segment re-cemented in place. 227 NATIONAL BOARD INSPECTION CODE FIGURE 8-5021 — Example of extensive fracture repair �� 8-5023 For minor fractures, such as those shown in Figure 8-5021, plug stitching can be used. The crack is removed by drilling and plugging a continuous chain of overlapping holes along the length and depth of fracture. 8-5030 �� FIGURE 8-5022 — Example of intermediate fracture repair �� FIGURE 8-5023 — Examples of minor fracture repair MINOR FRACTURE GRAPHITE REPAIR BY PLUG STITCHING (See Figure 8-5030) Plug stitching is a form of repair by material inlaying. In this case, the inlays are small cylindrical impervious graphite plugs. The crack or fracture is removed by drilling and plugging a continuous series of overlapping holes along its length and depth. Most plug stitching is done with 7/8 in. (22 mm) diameter plugs. The plugs are laid out along the fracture line on a pitch of 5/8 in. (16 mm) centers. The overlap of plug material is 1/4 in. (6 mm) along the fracture line. A number of plug sizes are available and are used in repair, and the amount of overlapping is proportional to their diameters. 8-5031 PLUG STITCHING PROCEDURE (See Figure 8-5030) The following procedure is defined for 7/8 in. (22 mm) diameter plugs11. Dimensions for other size plugs shall be adjusted proportionally to the diameter. �� Trace the line of fracture with acetone and mark its length and direction. Beyond the end points of the fracture (crack), one additional plug shall be installed. �� 11 228 plug: An undersized plug will allow the use of common size tooling. APPENDIX 8 — INSPECTION, REPAIR, AND ALTERATION OF GRAPHITE PRESSURE EQUIPMENT Starting 5/8 in. (16 mm) beyond the end point of the crack, mark drilling centers every 5/8 in. (16 mm) along its length. Make sure there is a plug to be installed outside both end points of the line of fracture. Drill a 1/4 in. (6 mm) pilot hole at each location. Redrill a 7/8 in. (22 mm) hole at every other pilot hole. Holes must be drilled the full depth of the crack. The depth and direction of the crack can be checked with acetone. A 7/8 in. (22 mm) diameter reamer may be used to true the drilled holes. Apply graphite cement to both plugs and holes. All surfaces of plugs and holes to be joined are to be wetted with cement. Insert the cemented plugs into the holes allowing 1/16 in. (1.5 mm) of the plug to extend beyond the surface of the graphite part. Cure the graphite cement according to the cement Manufacturer’s instruction. At this point, half of the plug stitch repair is completed. A row of plugs has been installed with 1/4 in. (6 mm) pilot holes between them. Dry fit a plug into the holes. There should be 0.005 in. to 0.010 in. (0.1 mm to 0.3 mm) clearance for the cement joint. At no time should there be a force fit of plugs into any drilled hole. Provisions shall be provided for venting trapped air. �� Sand the O.D. surface of the plugs. Thoroughly clean all the surfaces of the repair with acetone; plugs and drilled holes. �� FIGURE 8-5030 �� 229 NATIONAL BOARD INSPECTION CODE Redrill the remaining pilot holes to 7/8 in. (22 mm) diameter. The drill will remove part of the plugs which were installed. It is important to have the plugs replace all of the fracture. If the new holes do not cut into the installed plugs, it will be necessary to repeat the procedure between these holes and plug locations, to ensure that all of the crack has been repaired. The line of fracture is completely removed by the overlapping effect of the graphite plugs. After the second set of holes have been drilled, repeat the plug cementing procedures. Contour the plugs to provide a smooth transition into the adjoining surface area. The finished repair may be coated with a wash coat for appearance. 8-5040 Reimpregnation of the graphite may be used to enhance the performance and extend the life of graphite components. A written reimpregnation procedure acceptable to the Inspector is required. The reimpregnation procedure shall include as a minimum: • • • • • Decontamination and drying of the graphite component Subjecting the component to a vacuum Introducing resin under pressure Curing the resin at a specified temperature and time Leak test 8-5060 FIGURES – TYPICAL PLUG STITCHING PROCEDURE (See Figure 8-5030) CONTROL OF IMPREGNATION MATERIAL Impregnation material shall be the same as that specified in the Reimpregnation Procedure. Each impregnation material shall be traceable by the name of its manufacturer and the trade name or number of that manufacturer. Step one: Layout hole centers. Step two: Drilling pilot holes. Step three: Drilling the first set of holes. Step four: Cementing and curing the first set of plugs. Step five: Drilling the second set of holes. Step six: Plug stitching repair completed. 8-5050 in the pores. However, a hydrostatic test will determine if the graphite has continuous porosity. The impregnation material manufacturer shall supply the Certificate Holder a Certificate of Analysis for each material. It shall include the following: REIMPREGNATION OF GRAPHITE PARTS (TUBESHEETS, HEADS, AND BLOCKS) As a function of time, temperature, and chemical exposure, the resin used to impregnate graphite may shrink and/or degrade. As such, it is possible for voids to develop in impregnated graphite that has been in chemical service for a period of time. The resin loss can vary from slight to almost complete loss of impregnation. There is no practical way to determine the amount of resin remaining • • • • • • Impregnation material identification Batch number(s) Date of manufacture Shelf life Viscosity per ASTM D 2393 Specific gravity Prior to reimpregnation, and at subsequent intervals not to exceed 14 days, the Certificate Holder shall test each batch of impregnation material to assure that the characteristics of the material have not changed from values specified in the Reimpregnation Procedure. 230 APPENDIX 8 — INSPECTION, REPAIR, AND ALTERATION OF GRAPHITE PRESSURE EQUIPMENT The values obtained for viscosity and specific gravity for the impregnation material shall be within the limits specified by the manufacturer and as listed in the Reimpregnation Procedure. The test values shall be made available to the Inspector. 8-5070 FINISHING THE REPAIR The parts should be held in place to prevent movement while curing the cemented joint to achieve a proper repair. The repair firm should take care to ensure that the cement joint thickness is within the range recommended by the cement Manufacturer. Care spent in precisely aligning the parts while clamping will avoid many finishing and machining operations later. Particular attention should be given to gasket and other bearing surfaces. b. Apply a thin coating of cement onto the Code part. The cement should have the consistency of toothpaste. c. Apply sufficient heat to the cement so that it begins to form a skin. d. Apply a coating of a thinned release agent, such as “ANTISIEZE” to the tip of the “R” stamp with a brush. e. Press the coated stamp all the way to the bottom of the cement and remove by pulling straight out before the cement hardens. f. Cure or heat the impression as required. g. When cured, the part may be washed to remove any excess release agent. Gasket and bearing surfaces may have to be machined, filed, or sanded before the job is completed. Gasket serrations must be clean and continuous. Serrations can be easily re-cut into graphite and any repair plugs that cross the gasket surface. Application of characters directly to graphite a. Use a very thin template of a flexible material (stainless steel; flexible and easily cleaned). 8-6000 c. Hold the template securely and trowel over with approved cement to fill all of the template area. ALTERNATIVE MARKING AND STAMPING General Requirements a. This procedure may be used in lieu of the stamping and nameplate requirements defined in Appendix 2. b. The required data as defined in Appendix 2 shall be 5/32 in. (4 mm) high, minimum. c. The National Board code symbol (“R”) shall be used to make the impression in the cement. Application of the “R” Code Symbol a. The graphite surface shall be clean and smooth. b. Place the template over a clean smooth surface. d. Carefully lift the template from the graphite part and examine the detail of the characters. e. If acceptable, cure the cement. f. If the characters are incorrect or damaged, wipe off the cement with a compatible solvent and reapply. Note: The preceding methods can be applied jointly to identify the graphite part and to transfer the “R” stamp. 231 NATIONAL BOARD INSPECTION CODE 232 Repair, Alteration and Inspection of Fiber-Reinforced Thermosetting Plastic Pressure Equipment Appendix 9 Table 1 Visual Inspection Acceptance Criteria Reprinted from ASME B5.541992 by permission of the American Society of Mechanical Engineers. All rights reserved. 233 NATIONAL BOARD INSPECTION CODE APPENDIX 9 — FIBER-REINFORCED THERMOSETTING PLASTIC PRESSURE EQUIPMENT 9-1000 GENERAL REQUIREMENTS 9-1010 SCOPE This appendix provides general requirements that apply to repairs and alterations to fiber -reinforced pressure retaining items. The letters “RP” shall be included on the “R” Certificate of Authorization for those organizations authorized to perform repairs/alterations of fiber reinforced plastic pressure equipment. 9-1020 ited to the corrosion barrier or liners only, providing there is adequate access to the vessel surface that requires the repair. No structural repairs, rerating or alterations are permitted with the following exceptions: a. Repair of vessels fabricated using elevated temperature cured material is permitted only if the following provisions are met. 1. Calculations must be submitted by a Registered Professional Engineer (P.E.) experienced in the field of FRP vessels (See 9-3022). 2. The original fabricator must provide its approval showing that the damage does not compromise the pressure rating of the vessel and that the safety factor required by the ASME Code or the original code of construction is maintained. LIMITATIONS All field work shall be limited to secondary bonding. 9-1030 REPAIR LIMITATIONS FOR FILAMENT WOUND VESSELS When the MAWP is greater than 200 psig, field repair of filament wound ASME Code Section X, Class I vessels shall be limited to corrosion barrier or liner repairs only, provided there is access to the vessel interior. No structural repairs, re-rating, or alterations are allowed for filament wound ASME Code Section X, Class 1 vessels, that have an MAWP greater than 200 psig. 9-1031 b. Repair that results in a revision to the pressure rating of a vessel covered as a part of this section is permitted providing the new rating is less than the original rating and as long as the safety factor required by the ASME Code or the safety factor used as a design basis from the original code of construction is met in its entirety and all the requirements under 9-3000, Additional Requirements for Alterations are met. 9-1040 VESSELS FABRICATED USING ELEVATED TEMPERATURE CURED RESIN SYSTEMS Repair of vessels fabricated using elevated temperature cured resin systems shall be lim- CODE OF CONSTRUCTION When the standard governing the original construction is the ASME Code Section X or ASME RTP-1, repairs and alterations shall conform, insofar as possible, to the section and edition of ASME Code Section X or ASME RTP-1 most applicable to the work planned. 234 APPENDIX 9 — REPAIR, ALTERATION AND INSPECTION OF FIBER-REINFORCED THERMOSETTING PLASTIC PRESSURE EQUIPMENT When the standard governing the original construction is not the ASME Code Section X or ASME RTP-1, repairs and alterations shall conform to the original code of construction or standard. Where this is not possible, it is permissible to use other codes, standards, or specifications, including the ASME Code (Section X or RTP-1), provided the “RP” designated “R” Certificate Holder (hereafter called the Certificate Holder) has the concurrence of the Inspector and the jurisdiction where the pressure retaining item is installed. When ASME is the original code of construction, replacement parts subject to internal or external pressure which require shop inspection by an Authorized Inspector or by a Certified Individual as defined by ASME RTP shall be fabricated by an organization having an appropriate ASME Certificate of Authorization. The item shall be inspected and stamped or marked as required by the original code of construction. A completed ASME Fabricator’s Partial Data Report shall be supplied by the fabricator. The materials used in making repairs or alterations shall conform to the requirements of the original code of construction. All resins and reinforcements must be properly stored and prevented from being contaminated by water, soil or other impurities. The Certificate Holder is responsible for verifying identification of existing materials from original data, drawings, or units records and identification of the materials to be installed. Consideration shall be given to the condition of the existing laminate, especially in the secondary bond preparation area. When the original code of construction is other than ASME, replacement parts subject to internal or external pressure shall be manufactured by an organization certified as required by the original code of construction. The item shall be inspected and stamped as required by the original code of construction. Certification to the original code of construction as required by the original code of construction or equivalent shall be supplied with the item. When this is not possible or practicable, the organization fabricating the part may have a National Board Certificate of Authorization. Replacement parts shall be documented on Form R-3 and the “R” symbol stamp applied as described in Appendix 2. 9-1060 9-1070 9-1050 MATERIALS REPLACEMENT PARTS Replacement parts which will be subject to internal or external pressure including liquid head that are pre-assembled with or without secondary bonds shall have the fabrication performed in accordance with the original code of construction. The fabricator shall certify that the material and fabrication are in accordance with the original code of construction. This certification shall be supplied in the form of bills of material and drawings with statements of certification. Examples include shell and head sections, or flanged nozzles. SECONDARY BONDING Secondary bonding shall be performed in accordance with the requirements of the original code of construction used for the pressure-retaining item. 235 NATIONAL BOARD INSPECTION CODE 9-1071 SECONDARY BONDING PROCEDURE SPECIFICATIONS 9-1075 Secondary bonding shall be performed in accordance with the lamination procedure qualified in accordance with the original code of construction. 9-1072 PERFORMANCE QUALIFICATIONS Secondary bonders shall be qualified for the lamination process that is used. Such qualifications shall be in accordance with the requirements of the original code of construction. 9-1073 RECORDS The Certificate Holder shall maintain a record of the results obtained in secondary bonder procedure qualifications. These records shall be certified by the Certificate Holder and shall be available to the Inspector. 9-1074 SECONDARY BONDER’S IDENTIFICATION The Certificate Holder shall establish a system for the assignment of a unique identification mark for each secondary bonder qualified in accordance with the requirements of the NBIC. The Certificate Holder shall also establish a written procedure whereby all secondary bonds can be identified as to the secondary bonder who made them. The procedure shall be acceptable to the Inspector. The Certificate Holder shall keep a record of all secondary bonded joints and the secondary bonders who made the joints. SECONDARY BONDER’S CONTINUITY The performance qualification of a secondary bonder shall be affected when one of the following conditions occur: a. When the secondary bonder has not made joints using a specific qualified lamination procedure during a period of eighteen (18) months or more, the bonder’s qualifications for that procedure shall expire. b. When there is specific reason to question the bonder’s ability to make secondary bonds that meet the specification, the qualification which supports the secondary bonding that is being performed shall be revoked. All other qualifications not questioned remain in effect. 9-1080 CURING Curing techniques shall be performed as required by the original code of construction or by the resin manufacturer’s recommendations in accordance with a written procedure. The procedure shall contain the parameters for curing. 9-1090 NONDESTRUCTIVE EXAMINATION Except as required by this appendix, the nondestructive examination (NDE) requirements, including technique, extent of coverage, procedures, personnel qualifications, and acceptance criteria, shall be in accordance with the original code of construction used for the construction of the pressure-retaining item. Secondary bonded repairs and alterations shall be subjected to the same nondestructive 236 APPENDIX 9 — REPAIR, ALTERATION AND INSPECTION OF FIBER-REINFORCED THERMOSETTING PLASTIC PRESSURE EQUIPMENT examination requirements as the original secondary bonds. As a minimum, all secondary bonded joints made for repairs and alterations shall be subjected to a Barcol hardness test in accordance with ASTM D-2583 and an acetone wipe test for all polyester and vinyl ester resins. A visual inspection in accordance with Table 9-4100 is always required. The criteria for visual acceptance shall be the same as the original code of construction. • witness any pressure or acoustic emission test, • assure that the required nondestructive examinations have been performed satisfactorily, and • that the other functions necessary to assure compliance with the requirements of this Code have been performed. 9-1100 9-1130 PRESSURE AND ACOUSTIC EMISSION TESTS STAMPING All vessels subject to repairs other than those defined in 9-2040 shall be tested in accordance with the requirements of the original code of construction. In addition, all structural repairs and alterations shall be pressure tested. All vessels acoustic emission tested as required by the original code of construction shall be retested during the pressure test concentrating on the repaired or altered part of the vessel. The attaching of a nameplate to a repaired or altered vessel or tank shall indicate that the work was performed in accordance with the requirements of this Code. The attachment of a nameplate shall be done only with the knowledge and authorization of the Inspector. The Certificate Holder responsible for the repair or alteration shall apply the stamping nameplate. Required stamping and nameplate information are shown in Appendix 2. 9-1110 9-1140 PRESSURE GAGES, MEASUREMENT, AND EXAMINATION AND TEST EQUIPMENT The calibration of pressure gages, measurement, examination and test equipment and documentation of calibration shall be performed as required by the applicable standard used for construction. 9-1120 ACCEPTANCE INSPECTION Before signing the appropriate NBIC report form, the inspector: • shall review the drawings, • assure the secondary bonding was performed in accordance with the original code of construction, REMOVAL OF ORIGINAL STAMPING OR NAMEPLATE If it becomes necessary to remove the original stamping, the Inspector shall, subject to the approval of the Jurisdiction, witness the making of a facsimile of the stamping, the obliteration of the old stamping, and the transfer of the stamping to the new item. When the stamping is on a nameplate, the Inspector shall witness the transfer of the nameplate to the new location. Any relocation shall be described on the applicable NBIC form. ASME Code items shall not be restamped with the ASME Code Symbol. 237 NATIONAL BOARD INSPECTION CODE 9-1150 Organizations performing repairs or alterations under an “R” stamp program shall register such repairs or alterations with the National Board. 9-2000 ADDITIONAL REQUIREMENTS FOR REPAIRS 9-2010 SCOPE This section provides additional requirements for repairs to pressure-retaining items and shall be used in conjunction with 9-1000 and 9-4000. b. Authorized Acceptance Following review and certification, the repair plan shall be submitted to the Inspector for his review and acceptance. Repairs to pressure-retaining items shall not be initiated without the authorization of the Inspector. Subject to acceptance of the Jurisdiction, the Inspector may give prior approval for routine repairs, provided the Inspector assures that the Certificate Holder has acceptable procedures covering the repairs. 9-2040 9-2020 DRAWINGS Drawings shall be prepared or modified to describe the repair. Drawings shall include sufficient information to satisfactorily perform the repair. 9-2030 pair is compatible with the User’s Design Specification or User’s Basic Requirements Specification and the Manufacturer’s Design Report. The certification shall also include any drawings and calculations prepared as part of the repair plan. REGISTRATION OF DOCUMENTATION REPAIR PLAN Prior to performing routine repairs, the Certificate Holder should determine that routine repairs are acceptable to the jurisdiction where the work is to be performed. a. Acceptable routine repairs are listed below: 1. The addition or repair of non-load bearing attachments to pressure-retaining items where post curing is not required. When repairs other than those defined in 9-2040 are being made to ASME Section X or RTP-1 stamped equipment, the user shall prepare or cause to have prepared a detailed plan covering the scope of the repair. a. Professional Engineer Review The repair plan shall be reviewed and certified by a Professional Engineer who is registered in one or more of the states of the United States of America or the provinces of Canada and is experienced in reinforced plastic vessel design. The review and certification shall be such to ensure that the work involved in the re- ROUTINE REPAIRS 2. Replacement and repair of damaged corrosion liner areas in shells and heads shall not exceed 100 sq. in. (645 sq. cm.) and not exceed the original corrosion liner thickness. b. Routine repairs may be performed under the Certificate Holder’s quality system program; however, the requirement for in-process involvement of the Inspector and stamping are waived. See 9-2070. 238 APPENDIX 9 — REPAIR, ALTERATION AND INSPECTION OF FIBER-REINFORCED THERMOSETTING PLASTIC PRESSURE EQUIPMENT c. The process of controlling and implementing routine repairs shall be documented in the Certificate Holder’s quality system program. e. When pressure testing using liquids is not practical, other methods shall be used as follows: 1. The pressure test may be a pneumatic test provided the Certificate Holder has the concurrence of the Inspector, the jurisdictional authority where required, and the owner. Precautionary requirements of the applicable section of the original code of construction shall be followed. In addition, a pneumatic test shall always be monitored by acoustic emission examination. d. Routine repairs shall be documented on a Form R-1 Repair form with a statement on line 9, Remarks: “Routine Repair”. 9-2050 REPAIR METHODS The repair methods shall be acceptable to the inspector. Some methods of repair are contained in 9-4000. 9-2060 2. For vessels designed for vacuum, a vacuum test shall be carried out to the original test vacuum level of the vessel. During the vacuum test, the vacuum source may be left connected to the vessel to compensate for leakage at fittings. All vessels acoustic emission tested, as required by the original code of construction, shall be retested during the vacuum test concentrating on the repaired or altered part of the vessel. PRESSURE TESTING Except as permitted in (e) below, the following requirements apply to all repairs to pressureretaining items: a. Repairs shall be pressure tested to 110% of the maximum allowable working pressure stamped on the pressure-retaining item using water or other liquid medium. The Certificate Holder is responsible for all activities relating to pressure testing of repairs. b. Replacement parts used in repairs shall be pressure tested at the maximum allowable working pressure indicated on the pressure-retaining item being repaired. c. During a pressure test, where the test pressure will exceed the set pressure of the pressure relief device, the device shall be prepared as recommended by the device manufacturer. d. Hold time for the examination by the Inspector shall be the time necessary for the Inspector to conduct the examination. 9-2070 STAMPING Pressure-retaining items repaired in accordance with the NBIC shall have a nameplate as required by Appendix 2. Subject to the acceptance of the jurisdiction and the concurrence of the Inspector, nameplates may not be required for routine repairs (see 9-2040). In all cases, the type and extent of repairs necessary shall be considered prior to waiving the requirement. 9-2080 DOCUMENTATION Repairs that have been performed in accordance with the NBIC shall be documented on Form R-1 as shown in Appendix 5. Form R-4 shall be used to record additional data when space is insufficient on Form R-1. 239 NATIONAL BOARD INSPECTION CODE 9-2081 PREPARATION OF FORM R-1 a. Preparation of Form R-1 shall be the responsibility of the Certificate Holder performing the repair. b An Inspector shall indicate acceptance by signing the Form R-1. c. The Form R-3 and the Fabricator’s Data Report described in 9-1050 shall be a part of the completed Form R-1 and shall be attached thereto. 9-2082 9-3021 DISTRIBUTION Legible copies of the completed Form R-1, together with attachments, shall be distributed to the owner-user, the Inspector, the jurisdiction if required, and the Authorized Inspection Agency responsible for inservice inspection. Form R-1 shall be registered with the National Board as noted in 9-1150. Distribution of Form R-1 and attachments shall be the responsibility of the organization performing the repair. 9-3000 9-3010 ADDITIONAL REQUIREMENTS FOR ALTERATIONS SCOPE This section provides additional requirements for alterations to pressure-retaining items, and shall be used in accordance with 9-1000 and 9-4000. 9-3020 drawings, design calculations, specifications and instructions are prepared, obtained, controlled and interpreted to provide the basis for an alteration in accordance with the original code of construction. When a Fabricator’s Data Report is required by the original code of construction, a copy of the original Data Report shall be obtained for use in the design of the alteration. When the original Fabricator’s Data Report cannot be obtained, agreements on the method of establishing design basis for the alteration shall be obtained from the Inspector and the jurisdiction. The user shall prepare or cause to have prepared a detailed plan covering the scope of the alteration. a. Professional Engineer Review The alteration plan shall be reviewed and certified by a Professional Engineer (P.E.) who is registered in one or more of the states of the United States of America or the provinces of Canada and is experienced in reinforced plastic vessel design. The review and certification shall be such as to ensure that the work involved in the alteration is compatible with the user’s design specification and the Fabricator’s Data Report. b. Authorized Acceptance Following review and certification, the alteration plan shall be submitted to the Inspector for his review and acceptance. Alterations to pressure-retaining items shall not be initiated without the authorization of the Inspector. 9-3022 DESIGN The Certificate Holder performing alterations shall establish controls to ensure that all required design information, applicable ALTERATION PLAN CALCULATIONS A set of calculations shall be completed prior to the start of any physical work. All design work shall be completed by an organization experienced in the design portion of the stan- 240 APPENDIX 9 — REPAIR, ALTERATION AND INSPECTION OF FIBER-REINFORCED THERMOSETTING PLASTIC PRESSURE EQUIPMENT dard used for the construction of the item. All calculations for ASME Code Section X and RTP-1 alterations shall be certified by a P.E. experienced in reinforced plastic vessel design (See 9-3030). All calculations shall be made available for review by the Inspector. 9-3024 9-3023 9-3030 RERATING Rerating of a pressure-retaining item by increasing the maximum allowable working pressure (internal or external) or temperature , or decreasing the minimum temperature shall be done only after the following requirements have been met to the satisfaction of the jurisdiction at the location of the installation: a. Revised calculations verifying the new service conditions shall be prepared in accordance with the Certificate Holders Quality Control System. Rerating calculations for ASME Code Section X and RTP-1 vessels shall be performed by a P.E. experienced in the design of reinforced plastic pressure vessels. As appropriate, drawings shall be prepared to describe the alteration. Drawings shall include sufficient information to satisfactorily perform the alteration. d. The pressure-retaining item has been pressure tested, as required, for the new service conditions. This code does not provide rules for de-rating pressure retaining items; however, when the MAWP and or allowable temperature of a pressure retaining item is reduced, the jurisdiction wherein the object is installed should be contacted to determine if specific procedures should be followed. PRESSURE TESTING Except as permitted in (g) below, the following requirements apply for pressure testing of alterations to pressure-retaining items: a. When the alteration activity involves the installation of a replacement part and/or the alteration will impact the design pressure, the design temperature, or the design rated capacity, a pressure test, as required by the original code of construction, shall be conducted. An acoustic emission test is also required if the original vessel was so tested, unless a nozzle whose diameter is one tenth the vessel diameter or less is being added. The Certificate Holder is responsible for all activities related to pressure testing of replacement parts. The pressure test may be performed at the point of manufacture or point of installation. b. All rerating shall be established in accordance with the requirements of the construction standard to which the pressure-retaining item was built. c. Current inspection records verify that the pressure-retaining item is satisfactory for the proposed service conditions. DRAWINGS b. The pressure test of replacement parts and connecting secondary bonds shall be tested at 1.1 times the maximum allowable working pressure or the original test pressure, whichever is greatest. c. During the pressure test, where the test pressure will exceed the set pressure of the pressure relief device, the device shall be prepared as recommended by the device manufacturer. d. The liquid temperature used for pressure testing shall not be less than 40°F (4°C) nor more than 120°F (49°C) unless the 241 NATIONAL BOARD INSPECTION CODE original pressure test was conducted at a higher temperature. If an acoustic emission examination is being conducted, the temperature of the test liquid shall not vary by more than plus 5°F (3°C) or minus 10°F (6°C). requirements of the applicable section of the original code of construction shall be followed. 2. For vessels designed for vacuum, a vacuum test shall be carried out to as close as practical to the design vacuum level of the vessel. During the vacuum test the vacuum source may be left connected to the vessel to compensate for leakage at fittings. All vessels originally acoustic emission tested shall be retested during the vacuum test concentrating on the repaired or altered part of the vessel. e. Hold time for the pressure test shall be a minimum of 30 minutes with an acoustic emission examination or a minimum of 4 hours without an acoustic emission examination. The following procedure shall be used to retest a vessel that has been tested under the provisions of Article 6 of ASME Section X and has subsequently been repaired. 1. Load the vessel as specified in Article 6 of ASME Section X without monitoring for acoustic emission. 2. Hold the maximum load for at least 30 minutes. 3. Condition the vessel by holding at reduced load as required by Section V, Article 11, T-1121. 4. Retest the vessel as required by this appendix. 5. The vessel shall be judged against the evaluation criteria for subsequent loadings. f. Hold time for the examination by the Inspector shall be the time necessary for the Inspector to conduct the inspection. g. When pressure testing using liquids is not practical, other methods shall be used as follows: 1. The pressure test may be a pneumatic test provided the Certificate Holder has the concurrence of the Inspector, the jurisdictional authority where required, and the owner. Precautionary 9-3040 STAMPING The nameplate shall be applied in accordance with Appendix 2. The location of the nameplate shall be documented on the Form R-2. 9-3050 DOCUMENTATION Alterations performed in accordance with the NBIC shall be documented on Form R-2, Report of Alteration, as shown in Appendix 5. Form R-2, Report Supplementary Sheet, shall be used to record additional data when space is insufficient on Form R-4. 9-3051 PREPARATION The following items shall be attached to and become part of the R-2 report. a. Preparation of Form R-2 shall be the responsibility of the Certificate Holder performing the alteration. The Fabricator’s reports or Form R-3, as described in 91060, and for pressure vessels a copy of the original Fabricator’s Data Report, when available, shall be attached to and become a part of the completed Form R-2. 242 APPENDIX 9 — REPAIR, ALTERATION AND INSPECTION OF FIBER-REINFORCED THERMOSETTING PLASTIC PRESSURE EQUIPMENT b. The Certificate Holder that certifies the “Design Change” shall complete and sign the “Design Certification” section of the Form R-2. An Inspector shall indicate acceptance of the design by signing the “Certification of Design Change Review” section of Form R-2. c. The Certificate Holder performing the alteration shall complete and sign the “Construction Certification” section of the Form R-2. An Inspector shall indicate acceptance of the installation by signing the “Certificate of Inspection” section of Form R-2. 9-3052 The repair shall meet the requirements of the original construction standard. 9-4020 CLASSIFICATION OF REPAIRS Vessel repairs shall be classified into the following types: a. Type 1a – Corrosion barrier repairs Type 1b – Corrosion barriers with precision bores b. Type 2 – Corrosion barrier and interior structural layer repairs c. Type 3 – External structural layer repairs DISTRIBUTION Legible copies of the completed Form R-2, Report of Alteration, together with attachments, shall be distributed by the Certificate Holder performing the alteration, to the Inspector, the owner-user, and the jurisdiction, if required. One original shall be submitted to the National Board. d. Type 4 – Alterations e. Type 5 – Miscellaneous general external repairs or alterations f. Type 6 – Thermoplastic repairs g. Type 7 – Gel coat repairs 9-4000 REPAIR/ALTERATION METHODS Each type of repair shall have its own corresponding general repair procedure as given in the following paragraphs. 9-4010 GENERAL REQUIREMENTS 9-4021 In general, when a defective or damaged vessel wall is to be repaired, the total structural laminate sequence of laminate construction removed as part of the repair shall be replaced. The replacement laminate shall provide structural properties meeting or exceeding the requirement of the original construction standard. Moreover, when damage includes the corrosion barrier, a corrosion barrier of the same type, which shall meet or exceed the barrier properties of the original construction, shall replace the corrosion barrier removed as part of the repair. TYPE 1 – REPAIR OF THE CORROSION BARRIER A corrosion barrier that has been exposed to a process may be permeated to the point that in some cases the entire corrosion barrier laminate may need to be removed. After the Inspector has verified that the repair procedure is acceptable, the repair shall be performed by the Certificate Holder as follows: a. Surface Preparation The surface area that is damaged must be removed by abrasive blasting or grinding, 243 NATIONAL BOARD INSPECTION CODE to remove contaminated laminate and expose sound laminate. The edge of the repaired area must have a bevel of 2 in. minimum. 2. Coat the primed surface with the same resin to be used in the laminate repair. Apply 4 in. (100 mm) x 14 in. (350 mm) piece of polyester, such as Mylar®, strip to one edge of primed area. Allow the polyester film to protrude from beneath the patch. Note that any cracks, delaminations, or permeated surface must be removed. An adequate size abrasive, or proper sanding disc must be used to obtain a 2-3 mil anchor pattern. 3. Apply two layers of 1-1/2 oz. (40 g)/ sq. ft. chopped strand mat saturated with the same resin that will be used for the repair. Mat shall be 12 in. (300 mm) x 12 in. (300 mm) square. Preparation of any surface requires that basic rules, common to all substrates, be followed. These rules are as outlined below: • • • • • 4. Allow the mat layers to cure completely, this may be verified by checking the hardness of the laminate. Surface must be free of contaminants. Surface must be structurally sound. Surface must have adequate anchor pattern. Surface must be dry. Surface must be primed with recommended primer. Note: After the surface has been properly prepared, it must be kept clean and dry until laminating can be started. Dust, moisture, or traces of oil that come in contact with the surface may act as a mold release or act to inhibit the cure and prevent a good secondary bond. b. Applying Test Patches to Verify Adequate Surface Preparation Test patches should be applied to any substrate that will require a secondary bond to determine the integrity of the primer bond prior to the application of the laminate. The subsequent steps shall be followed: 1. Apply the primer (3 to 5 mils) to the prepared surface, and allow primer to cure. 5. Pry patch from surface using a screwdriver, chisel, or pry bar. 6. A clean separation indicates a poor bond. 7. Torn patch laminate or pulled substrate indicates that the bond is acceptable. If the bond is not adequate, go back to step (a) and repeat the procedure. Note: If the repair area is smaller than the test patch dimensions, decrease the test patch size accordingly. As a last resort, if the previous procedure does not provide an adequate bond, the permeated laminate must be handled differently using the following procedure: • Hot water wash the equipment. • Abrasive blast with #3 sand or equal and allow to completely dry. • Prime with the recommended primer, an area 12 in. (300 mm) x 12 in. (300 mm) and apply a test patch. 244 245 NONE *1/8 in. (3 mm) dia. max. by 50% of veil(s) thickness max. NONE NONE *1/8 in. (3 mm) dia. max. by 30% of veil(s) thickness max. NONE NONE NONE Showing evidence of thermal decomposition through discoloration or heavy distortion Small pieces broken off an edge or surface Actual ruptures or debond of portions of the structure Fine cracks at the surface of a laminate Separation of the layers in a laminate Burned Areas Chips (surface) Cracks Crazing (surface) Delamination (internal) NONE NONE Level 2 Level 1 Definition of Imperfection Inner Surface Veil(s), Surfacing Mat Imperfection Name Definition of Visual Inspection Levels (to be Specified User or User’s Agent): Level 1 = Critically Corrosion Resistant Level 2 = Standard Corrosion Resistant NONE NONE NONE Level 1 NONE NONE NONE Level 2 Interior Layers Thick Mat or Chopped Strand Spray Layers Max. 2 in. (50 mm) long by 1/64 in. (.4 mm) deep, max. density 5 in. (125 mm) any sq. ft. *None in three plies adjacent to interior layer, none larger than 1 sq. in. (650 mm2) in total area Max. 1 in. (25 mm) long by 1/64 in. (.4 mm) deep, max. density 3 in. (75 mm) any sq. ft. NONE Not to include areas to be covered by joints *1/4 in. (6mm) dia. or 1/2 in. (13mm) length max. by 1/16 (1.5mm) in. deep *1/4 in. (6mm) dia. or 1/2 in. (13mm) length max. by 1/16 (1.5mm) in. deep NONE Discoloration only, never delamination or decomposition Never in more than one ply and not to exceed 16 sq. in. (10,500 mm2) in any vessel NONE NONE Notes Level 2 Level 1 Structural Layers Balance of Laminate (Including Outer Surface) Maximum Size and Cumulative Sum of Imperfections Allowed After Repair. (See General Notes (a) and (b). Imperfections Subject to Cumulative Sum Limitations are indicated with an asterisk). TABLE 9-4021 — Visual Inspection Acceptance Criteria APPENDIX 9 — REPAIR, ALTERATION AND INSPECTION OF FIBER-REINFORCED THERMOSETTING PLASTIC PRESSURE EQUIPMENT 246 Max. dia. 1/8 in. (3 mm) * 1/2 in. (13 mm) long max. by dia. or thickness not more than 30% of veil(s) thickness Level 1 Max. dia. 1/8 in. (3 mm) * 1/2 in. (13 mm) long max. by dia. or thickness not more than 50% of veil(s) thickness. Level 2 Interior Layer (-0.125 in. (3 mm) Thick) Mat or Chopped Strand Spray Layers Max. dia. 3/16 in. (5 mm) *Dime size, never to penetrate lamination to lamination. NONE NONE Level 1 Max. dia. 1/4 in. (6 mm) *Nickel size, never to penetrate lamination to lamination. NONE NONE Level 2 Structural Layer Balance of Laminate (Including Outer Surface) Refer to User’s Specification for quantity limitations Max. dia. 1/16 in. (1.5 mm) by 50% of veil(s) thickness deep Max. dia. 1/16 in. (1.5 mm) by 30% of veil(s) thickness deep Particles included in a laminate which are foreign to its composition (not a minute speck of dust) Foreign Inclusion Gaseous Bubbles or Blisters Air entrapment within, on, or between plies of reinforcements, 0.015 in. diameter and larger NONE NONE Exposure of multiple layers of the reinforcing matrix to the vessel contents, usually as a result of shaping or cutting a section to be secondary bonded (interior of vessel only) Edge Exposure * 1/4 in. (6 mm) long max. by dia. or thickness not more than 50% of veil(s) thickness NONE NONE Areas of surface where the reinforcements have not been wetted with resin. Dry Spot (surface) *3/16 in. (5 mm) long max. by dia. or thickness not more than 30% of veil(s) thickness Level 2 Level 1 Definition of Imperfection Inner Surface Veil(s), Surfacing Mat Imperfection Name Definition of Visual Inspection Levels (to be Specified User or User’s Agent): Level 1 = Critically Corrosion Resistant Level 2 = Standard Corrosion Resistant Maximum Size and Cumulative Sum of Imperfections Allowed After Repair. (See General Notes (a) and (b). Imperfections Subject to Cumulative Sum Limitations are indicated with an asterisk.) TABLE 9-4021 — Visual Inspection Acceptance Criteria, continued Must not be breakable with a sharp point Must be fully resin wetted and encapsulated. Edges exposed to contents must be covered with same number of veils as inner surface. Notes NATIONAL BOARD INSPECTION CODE 247 Resin has failed to saturate reinforcing (particularly woven roving). Wet-Out Inadequate NONE *None over 3/16 in. (5 mm) dia. by 1/16 in. (1.5 mm) in height *None over 3/16 in. (5 mm) dia. by 1/16 in. (1.5 mm) in height Rounded elevations of the surface, somewhat resembling a blister on the human skin; not reinforced Wet Blisters (surface) NONE NONE NONE Shallow marks, grooves, furrows, or channels caused by improper handling Scratches (surface) None more than 50% of veil(s) thickness None more than 30% of veil(s) thickness *1/8 in. (3 mm) dia. max. by 30% of veil(s) thickness max. *1/8 in. (3 mm) dia. max. by 30% of veil(s) thickness max. Small crater in the surface of a laminate. Pit (surface) Presence of numerous visual tiny pits (pinholes), approximate dimension 0.005 in. (0.1 mm) (for example, 5 in. any sq. in. [650 sq. mm.]) *Max. height or diameter 1/64 in. (.4 mm) *Max. height or diameter 1/64 in. (.4 mm) Small, sharp, conical elevations on the surface of a laminate. Pimples (surface) Porosity (surface) Level 2 Level 1 Definition of Imperfection Inner Surface Veil(s), Surfacing Mat Imperfection Name Definition of Visual Inspection Levels (to be Specified User or User’s Agent): Level 1 = Critically Corrosion Resistant Level 2 = Standard Corrosion Resistant NONE Level 1 NONE Level 2 Interior Layer (-0.125 in. (3 mm) Thick) Mat or Chopped Strand Spray Layers *1/4 in. (6 mm) dia. max. by 3/32 in. (2.5 mm) deep max. No Limit Level 2 No Limit Dry mat or prominent and dry woven roving pattern not acceptable; discernible but fully saturated woven pattern acceptable. No Limit None to fully penetrate the exterior get coat or get coated exterior veil. No quantity limit. *None more *None more than 6 in. than 12 in. long long (150 mm) (300 mm) *1/4 in. (6 mm) dia. max. by 1/16 in. (1.5 mm) deep max. No Limit Level 1 Structural Layer Balance of Laminate (Including Outer Surface) Maximum Size and Cumulative Sum of Imperfections Allowed After Repair. (See General Notes (a) and (b). Imperfections Subject to Cumulative Sum Limitations are indicated with an asterisk.) TABLE 9-4021 — Visual Inspection Acceptance Criteria, continued Split tests on cutouts may be used to discern degree of saturation on reinforcing layers. Must be fully resin filled; not drips loosely glued to surface, which are to be removed No fibers may be exposed. No fibers may be exposed. No fibers may be exposed Must be fully resin filled and wetted; generally captured sanding dust Notes APPENDIX 9 — REPAIR, ALTERATION AND INSPECTION OF FIBER-REINFORCED THERMOSETTING PLASTIC PRESSURE EQUIPMENT 248 Max. deviation 20% of wall or 1/8 in. (3 mm), whichever is least 5 20 Max. deviation 20% of wall or 1/16 in. (1.5 mm), whichever is least 3 16 Generally linear, abrupt changes in surface plane caused by laps of reinforcing layers, irregular mold shape, or Mylar® overlap. Maximum allowable in any square feet (sq. 0.3 m) Maximum allowable in any square yard (sq. m) Wrinkles and Creases Allowable Cumulative Sum of Highlighted Imperfections 20 3 Level 1 30 5 Level 2 Interior Layer (-0.125 in. (3 mm) Thick) Mat or Chopped Strand Spray Layers GENERAL NOTES a. Above acceptance criteria apply to condition of laminate after repair and hydro test. b. Non-catalyzed resin is not permissible to any extent in any area of the laminate. Level 2 Level 1 Inner Surface Veil(s), Surfacing Mat Definition of Imperfection Imperfection Name Definition of Visual Inspection Levels (to be Specified User or User’s Agent): Level 1 = Critically Corrosion Resistant Level 2 = Standard Corrosion Resistant Level 2 30 5 40 5 Maximum deviation 20% of wall or 1/8 in. (3 mm), whichever is least Level 1 Structural Layer Balance of Laminate (Including Outer Surface) Maximum Size and Cumulative Sum of Imperfections Allowed After Repair. (See General Notes (a) and (b). Imperfections Subject to Cumulative Sum Limitations are indicated with an asterisk.) TABLE 9-4021 — Visual Inspection Acceptance Criteria, continued Not to cause a cumulative linear defect (outside defect adding to inside defect) Notes NATIONAL BOARD INSPECTION CODE APPENDIX 9 — REPAIR, ALTERATION AND INSPECTION OF FIBER-REINFORCED THERMOSETTING PLASTIC PRESSURE EQUIPMENT • Prime a second spot 12 in. (300 mm) x 12 in. (300 mm) and prime with a recommended epoxy resin primer. • Allow this primer to cure. • Water wash, dry, and lightly abrasive blast the epoxy primer. • Apply the test patches to both areas. area. The following chopped strand mat layer shall extend a minimum of 1 in. (25 mm) past the first layer, (in this manner, the entire area that was removed will now be filled with the mat layers. If additional layers are required to fill the removed surface, they must be applied), followed by the specified layer(s) of veil. The veil(s) shall extend a minimum of 1 in. (25 mm) past the last chopped strand mat layer. Pull both test patches after they are fully cured. 3. Apply a final coat of resin over entire surfacing veil. This final coat should contain a small amount of wax to prevent air contact, which might inhibit the cure. Allow laminate to achieve the manufacturer’s recommended Barcol hardness before finalizing the repair. Note: Apply heat to finalize the cure if hardness is not achieved. If both test patches are good, prime the vessel with the preferred primer. If only one test patch is good, prime the vessel with the successful primer. Note: if the repair area is smaller than the test patch dimensions, decrease the test patch size accordingly. If neither patch bonds, the vessel is probably not capable of bonding a patch and shall not be repaired. c. Laminate Repair Repairs can be accomplished by adding back the correct corrosion barrier surface material as specified on the Fabricator’s design drawings. 9-4022 TYPE 1B – REPAIR OF THE CORROSION BARRIER FOR VESSELS WITH PRECISION BORES 1. Apply the selected primer (3 to 5 mils) and allow to dry to the touch. Vessels with precision bores are commonly used when a device is installed inside the vessel and a seal between the device and the inside diameter is required. A corrosion barrier of a precision bore vessel is (susceptible) to scratching and damage that may affect performance and service life of the vessel or the device placed inside the vessel. Many times this damage may extend into areas of the vessel that cannot be reached. Before starting, ensure that the damaged area can be reached. After the Inspector has verified that the repair procedure is acceptable, the repair shall be performed by the certificate Holder as follows: 2. Continue with the specified laminate using the proper resin and cure. The first layer of chopped strand mat used in the repair shall extend a minimum of 1 in. (25 mm) past the damaged a. Surface Preparation The surface area that is damaged must be removed by abrasive blasting or grinding, to expose sound laminate. No more than 0.020 may be removed from the wall of the All repairs shall be made with the same type of resin and reinforcement materials used to fabricate the original vessel corrosion barrier. Laminate quality shall be in accordance with Table 9-4021. The acceptance criteria shall be as agreed by the certificate holder and owner or as required by the code of construction. 249 NATIONAL BOARD INSPECTION CODE vessel. The repaired area shall be beveled into the good areas surrounding the damage. Note that any cracks, delaminations, or permeated surfaces must be removed. If the damage is deeper than the corrosion barrier and the material removed reaches the structural laminate, the vessel is not repairable. An adequate size abrasive, or proper sanding disc must be used to obtain a 2-3 mil anchor pattern to the area that requires the repair. Preparation of any surface requires that basic rules, common to all substrates, be followed. These rules are as outlined below: • • • • • Surface must be free of contaminants Surface must be structurally sound Surface must have adequate anchor pattern Surface must be dry Surface must be primed with recommended primer Note: After the surface has been properly prepared, it must be kept clean and dry until laminating can be started. Dust, moisture, or traces of oil that come in contact with the surface may act as a mold release or act to inhibit the cure and prevent a good secondary bond. Laminating should be done within two hours of the surface preparation. b. Applying Test Patches to Verify Adequate Surface Preparation Test patches may be applied to any substrate that will require a secondary bond to determine the integrity of the bond prior to the application of the laminate. The subsequent steps shall be followed: 1. Apply the primer (3 to 5 mils) to the prepared surface, and allow primer to cure. 2. Coat the surface with the same resin to be used in the laminate repair. Apply a small strip of polyester film, such as Mylar®, strip to one edge of primed area. Allow the polyester film to protrude from beneath the patch. 3. Apply two layers of 1-1/2 oz. (40 g)/ sq. ft. chopped strand mat saturated with the same resin that will be used for the repair. 4. Allow the mat layers to cure completely, this may be verified by checking the hardness of the laminate. If required, heat may be used to cure the material providing it is compatible with the initial resin used in the fabrication of the vessel. 5. Pry patch from surface using a screwdriver, chisel, or pry bar. 6. A clean separation indicates a poor bond. 7. Torn patch laminate or pulled substrate indicates that the bond is acceptable. If the bond is not adequate, go back to step (a) and repeat the procedure again. Note: if the repair area is smaller than the test patch dimensions, decrease the test patch size accordingly. If neither patch bonds, the vessel is probably not capable of bonding a patch and shall not be repaired. 250 APPENDIX 9 — REPAIR, ALTERATION AND INSPECTION OF FIBER-REINFORCED THERMOSETTING PLASTIC PRESSURE EQUIPMENT c. Laminate repair Repairs can be accomplished by adding back the correct corrosion barrier surface material as specified on the Fabricator’s design drawings. When possible repairs shall be made with the same type of resin and reinforcement materials used to fabricate the original vessel corrosion barrier. Laminate quality shall be in accordance with Table 94021, or the original code of construction. However, when the original material of construction was gelled and post cured at elevated temperatures, using the same resin may not be possible. In this case an alternate resin system may be used. 1. Apply the selected primer (3 to 5 mils) (as required for polyester and vinyl ester resins) and allow to dry to the touch. 2. Continue with the specified laminate using the proper resin and cure. The first layer of non-woven polyester veil used in the repair shall extend to the exact edge of the damaged area. If additional layers are required to fill the removed surface, they must be applied, followed by the specified layer(s) of veil. 3. Apply a final coat of resin over entire surfacing veil. If this final coat is a vinyl ester or polyester material, it should contain a small amount of wax to prevent air contact, which might inhibit the cure. Allow laminate to achieve the manufacturer’s recommended Barcol hardness before finalizing the repair. Note: Apply heat to finalize the cure if hardness is not achieved. 4. After the repair has been properly cured, remove any excess material with the appropriate sanding tools to obtain a smooth surface that blends into the surrounding area. Care should be take to ensure that the final inside diameter of the repaired area matches that of the surrounding area and also conforms to the original suppliers specifications. 9-4023 TYPE 2 – CORROSION BARRIER AND INTERNAL STRUCTURAL LAYER REPAIRS The Procedure for the Type 1a repair must be followed with the exception of additional layers (structural layers) that must be removed if the structure is also damaged. The repair area must be tapered similar to the Type 1, and all of the structural layers must be replaced making sure that the mat layers increase in length and width by at least 1 in. The structural laminate sequence and thickness must be approved by the Inspector, and proper calculations and the repair plan must be reviewed and approved by a P.E. familiar with the work involved prior to the job. Surface preparation, priming, and laminate repair must be done per Type 1 procedure. 9-4024 TYPE 3 – EXTERNAL STRUCTURAL LAYER REPAIRS a. Surface Preparation The surface area that is damaged is to be repaired by removing the damaged area either by abrasive blasting or grinding to expose sound laminate. The repair area must have a bevel of 2 in. (50 mm) minimum. The ground or blasted surface must extend a minimum of 4 in. (100 mm) past 251 NATIONAL BOARD INSPECTION CODE the damaged area into the sound solid structural laminate, (making sure that no layers are removed in these four inches) or as calculated accordingly. 2. Coat the primed surface with resin to be used in the repair. Apply 4 in. (100 mm) x 14 in. (350 mm) Mylar® strip to one edge of primed area. Allow polyester film to protrude from beneath the patch. Note that any cracks, or delaminations must be removed. An adequate size abrasive, or proper sanding disc must be used to obtain a 2-3 mil anchor pattern. 3. Apply two layers of 1-1/2 oz. (40 g)/ sq. ft. chopped strand mat saturated with the specified resin that will be used for the repair. Mat shall be 12 in. (300 mm) x 12 in. (300 mm) square. Preparation of any surface requires that basic rules, common to all substrates, be followed. These rules are as outlined below: • Surface must be free of contaminants • Surface must be structurally sound • Surface must have adequate anchor pattern • Surface must be dry • Surface must be primed with recommended primer Note: After the surface has been properly prepared, it must be kept clean and dry until laminating can be started. Dust, moisture, or traces of oil that come in contact with the surface may act as a mold release or act to inhibit the cure and prevent a good secondary bond. Laminating should be done within two hours of the surface preparation. b. Applying Test Patches to Verify Adequate Surface Preparation Test patches may be applied to any substrate that will require a secondary bond to determine the integrity of the primer bond prior to the application of the laminate. 4. Allow to cure completely, this may be verified by checking the hardness of the laminate. 5. Pry patch from surface using a screwdriver, chisel, or pry bar. 6. A clean separation indicates a poor bond. 7. Torn patch laminate or pulled substrate indicates that the bond is acceptable. If the bond is not adequate, go back to step 1 and prepare the surface again. Note: If the repair area is smaller than the test patch dimensions, decrease the test patch size accordingly. c. Laminate Repair Repairs can be accomplished by adding back the correct equivalent contact molded laminate material as specified on the Fabricator’s design drawings, or in the Repair Plan. The subsequent steps shall be followed: 1. Apply the primer (3 to 5 mils) to the prepared surface, and allow primer to cure. 252 All repairs shall be made with the same type of resin and reinforcement materials used to fabricate the original vessel. Laminate quality shall be in accordance with the original construction code as specified in the vessel drawings and specifications. APPENDIX 9 — REPAIR, ALTERATION AND INSPECTION OF FIBER-REINFORCED THERMOSETTING PLASTIC PRESSURE EQUIPMENT 1. Apply the selected primer (3 to 5 mils) and allow to dry to the touch. 2. Continue with the specified laminate using the proper resin and cure. 3. Fill the removed layers with the same sequence as the original structural thickness, making sure that the layers are increasingly larger as the laminate is applied (in the case of filament wound structure, an equivalent contact molded thickness must be used for the repair calculations). The first bond of the repair shall cover 1 degree times the width in the axial direction and shall be centered. The repair shall extend completely around the circumference using contact molded procedures as set forth in the code of construction. 4. After the area is completely filled with the proper laminate, a reinforcing laminate shall be applied over the entire surface with a minimum overlap of four inches over the original shell, or as shown in the calculations, whichever is greater. This overlay thickness shall be calculated in the same way as the reinforcing pad of a nozzle with the diameter equal to the damaged area. The design shall be in accordance with the original construction code. Allow the laminate to achieve the manufacturer’s recommended Barcol hardness before finalizing the repair. Note: Apply heat to finalize the cure if hardness is not achieved. 5. A pressure test shall be performed per 9-3030. 9-4025 TYPE 4 – ALTERATIONS Alterations, such as the addition of a nozzle or supports, must be designed according to the original construction standard. In the case of nozzles, the internal overlay is required according to ASME RTP-1 Figure 4-8 or 4-9 (overlay “ti”). The procedure for preparing the inside surface is the same as the Type 1 repair. The external reinforcing pad shall be designed and installed according to the original construction standard. Surface preparation for the external overlay shall be according to the Type 3 repair procedure. After the alteration is completed, a pressure test shall be performed in accordance with 9-3030. As an option, an Acoustic Emission test can be performed to monitor the repaired area during the pressure test. 9-4026 TYPE 5 – MISCELLANEOUS GENERAL EXTERNAL REPAIRS OR ALTERATIONS External repairs or alterations that are performed on non-pressure containing parts, shall be calculated according to the original construction standard. The Inspector and the P.E. must review and approve such modifications. All repairs and alterations shall be done according to the Type 3 repair procedure, with the exception of removing damaged layers from the structure. Surface preparation shall be restricted to the external layer of the vessel. 9-4027 TYPE 6 – THERMOPLASTIC REPAIRS The surface area that is damaged must be reconditioned so that the thermoplastic liner geometry matches that of its contacting laminate. Surfaces that are cut or torn or missing sections shall be repaired by plastic welding. Welding practice, including choice of welding equipment, weld surface preparation, and weld temperature shall conform to Appendix M-14 of ASME RTP-1. For materials not specified in these documents, the best practice as recommended by the material supplier shall be used. Welding rod, pellets, powder, or 253 NATIONAL BOARD INSPECTION CODE plates shall be made with plastic of an identical type with properties such as melt index and specific gravity as close as possible to the original corrosion barrier plastic. Thickness of the repaired barrier between the wetted surface and the original surface shall be equal to or greater than the original corrosion barrier surface specification. The repaired surface shall be capable of supporting the full pressure rating of the vessel at the temperature rating of the vessel with no fluid leakage. 9-4028 TYPE 7 – GEL COAT REPAIRS Following restoration of the structural laminate layers, a gel coat shall be applied to replace the gel coat lost in the repair. The procedure for the Type 1 repair item (a) surface preparation shall be followed. Gel coat of the same type is then to be applied to the surface. Gel coat thickness is to be checked with a wet thickness gage at each 36 sq. in. area element. Thickness shall be equal to or greater than the original gel coat specification in the “as manufactured” state of the vessel. The entire repair surface including all seams shall be coated. There shall be at least a 3 in. overlap of gel coat at the union of repaired surface and non-repaired surface. 9-5000 9-5100 GENERAL Typical FRP equipment consists of the structural laminate (pressure retaining material) and a liner (corrosion barrier) to protect the structural laminate; Fig 9-5100-1. The structural laminate is defined as one or more layers of reinforced resin material bonded together. In addition to damage from mechanical sources, FRP material may be susceptible to damage from acids, alkalis, compounds containing fluorine, solvents, and hot clean water. For equipment fabricated with a liner, the primary purpose of a process side inspection is to assure the integrity of the liner to prevent chemical attack and degradation of the structural laminate. For equipment fabricated without a liner, the purpose of a process side inspection is to determine the condition of the structural laminate. In addition to chemical attack, the laminate is also susceptible to damage from: • • • excessive service temperatures, mechanical or service abuse, ultra-violet light (See 9-5520) Figure 9-5100-1 — Typical vessel Shell INSERVICE INSPECTION Part RB shall apply to inspection of Fiber Reinforced Plastic (FRP) equipment, except as modified herein. This section covers vessels and tanks only and was not written to cover piping and ductwork, although some of the information contained herein may be used for the inspection of piping and ductwork. Note: the liner (a) and the corrosion layer (b) are optional. a = liner b = corrosion layer c = structural laminate 254 APPENDIX 9 — REPAIR, ALTERATION AND INSPECTION OF FIBER-REINFORCED THERMOSETTING PLASTIC PRESSURE EQUIPMENT 9-5200 VISUAL EXAMINATION Exposed surfaces shall be visually examined for defects, and mechanical or environmental damage in the liner or the laminate. Classification and acceptance of any defects in the liner or laminate shall be according to Table 9-4021 in this Appendix. Defects to look for include: • • • • • • • • • • • Cracks Separation of secondary edges Leaks, especially around nozzles Discolored areas Areas of mechanical damage such as impacts or gouges. Surface deterioration; fiber exposure Cracked or broken attachments Damage due to dynamic loading Defective supports Delaminations Blisters 9-5300 9-5420 9-5430 9-5410 PREPARATION TOOLS The following tools may be required by the inspector. • The inspector shall be familiar with FRP equipment and qualified by experience for such inspections. The inspector shall be able to read a Jaeger Type No. 1 Standard Chart at a distance of not less than 12 in. (300 mm). The inspector shall be capable of distinguishing and differentiating contrast between colors. Visual acuity shall be checked annually to assure natural or corrected near distance acuity. ASSESSMENT OF INSTALLATION LEAKAGE Any leak shall be thoroughly investigated and corrective action initiated. Repairs shall be in accordance with 9-2000. INSPECTOR QUALIFICATIONS 9-5400 tenance and operation, as a guide in forming an opinion of the care the equipment receives. The history of the equipment shall be established, and shall include: date built, service history, maintenance, and a review of previous inspection records. Process conditions shall be reviewed to identify areas most likely to be attacked. Surface cleaning procedures and requirements shall also be reviewed. An observation shall be made of the condition of the complete installation, including main- • • • • • • Adequate lighting including overall lighting and a portable lamp for close inspections Hand held magnifying glass Barcol hardness tester Small pick or pen knife Small quantity of acetone and cotton swabs Camera with flash capability Liquid penetrant testing kit 9-5440 SAFETY Inspectors shall take all safety precautions when examining equipment. Proper personal protective equipment shall be worn, equipment shall be locked out, blanked off, decontaminated, and confined space entry permits obtained before internal inspections are conducted. In addition, inspectors shall comply with plant safety rules associated with the equipment and area in which they are inspecting. Inspectors are also cautioned that a thorough decontamination of the interior of 255 NATIONAL BOARD INSPECTION CODE vessels is sometimes very hard to obtain and proper safety precautions must be adhered to prevent contact or inhalation injury with any extraneous substance which may remain in the tank or vessel. 9-5500 EXTERNAL INSPECTION 9-5510 INSULATION OR OTHER COVERINGS EXPOSED SURFACES Exposed surfaces of pressure equipment are subject to mechanical, thermal, and environmental damage. Exposed surfaces may show damage from impact, gouging, abrasion, scratching, temperature excursions, etc. Sunlit areas may be degraded by ultraviolet light with a resulting change in surface color and increased fiber prominence, but with no loss in physical properties. Overheating may also cause a change in color. 9-5530 Areas that should be closely examined are: • • • • • • • Nozzle attachments Gusset attachments Flanges Secondary joints Hold down lugs Lifting lugs Attachments. STRUCTURAL ATTACHMENTS Attachments of legs, saddles, skirts, or other components shall be examined for cracks where the component attaches to or contacts the vessel and the component itself. See Figure 9-5900-r. 9-5550 It is not necessary to remove insulation and corrosion resistant covers for examination of the pressure equipment, if the coverings show no sign of mechanical impact, gouging, scratching, leaks, etc., and there is no reason to suspect any unsafe condition behind them. Where insulation coverings are impervious, such as a sealed fiberglass jacket, it is recommended that weep or drain holes be installed at the bottom of the insulation jacket as a means to detect leakage. 9-5520 9-5540 Piping loads on nozzles may be excessive. Therefore, all nozzles shall be closely examined for cracks as shown in Fig. 9-5900-p and 9-5900-cc. 9-5560 The location of external damage should be noted so that the opposing internal surface at that location can be examined. For example, an impact load applied to the outer surface may be transmitted through the laminate causing a star crack in the inner surface. See Figure 9-5900-t. 9-5600 INTERNAL INSPECTION 9-5610 FRP surfaces shall be dry and clean for the inspection. Every effort shall be made to minimize damage to the liner during inspection. Defects to look for include: • • • • • • • • • • • 256 Indentations Cracks Porosity Exposed fibers Lack of resin Delaminations Thinning at points of fluid impingement Blisters Scratches Gouges Discolorations. APPENDIX 9 — REPAIR, ALTERATION AND INSPECTION OF FIBER-REINFORCED THERMOSETTING PLASTIC PRESSURE EQUIPMENT 9-5620 GENERAL All surfaces shall be examined with both direct and oblique illumination. Color differences, opacity, stains, wetness, roughness, or any deviation from the original surface (original cutout sample) condition shall be noted and investigated. Liquid level lines shall be defined so the laminate condition in both the wet and dry zones can be determined. The following areas should be closely examined for cracks, porosity, or chemical attacks on the liner or laminate: • • • • • • • Fittings Changes in shape Baffles Secondary overlays Nozzles Cut edges Supports/internal structures & areas of attachment. 9-5630 EXAMINATION The inspector shall look for cracks, porosity, and any indication of deterioration of the liner and/or laminate. Liquid penetrant examination per RT-630 of ASME Section X may be used to locate and determine the extent of cracks. Deterioration of the surface may include softening or fiber prominence. A Barcol 934-1 hardness test (ASTM D-2583) shall be performed on areas of suspected laminate degeneration and areas that appear in good condition for comparison purposes. If the average Barcol test data indicates that the surface hardness of the laminate surfacing veil is below 70% of the minimum acceptable hardness specified by the resin manufacturer for a clear resin casting, then it is recommended that the inspector consult with the resin manufacturer as to the integrity of the liner laminate. Note that resin hardness values may be lower than the initial value for new equipment. This should not be cause for concern if the complete veil portion of the corrosion resistant barrier is still present; retention of resin hardness is dependent on the environment to which resin laminates are exposed. Even if the veil is gone, there is generally another 80-mils of corrosion resistant barrier remaining consisting of resin and chopped strand glass mat. The resin hardness of a corrosion barrier without the veil may be higher since the glass content of that portion of the laminate is higher. The resin hardness values should be used to monitor the condition of the laminate over time as compared to the initial hardness value. If the corrosion resistant barrier shows severe attack (for example, loose chopped strand glass mat fibers) that penetration of the corrosion barrier appears imminent before the next scheduled inspection, it should be repaired. 9-5700 RECORD KEEPING A detailed record of external and internal inspections shall be retained by the owner for the life of the FRP equipment. 9-5800 INSPECTION FREQUENCY 9-5810 NEWLY INSTALLED EQUIPMENT a. The following factors should be considered when determining the frequency of inspection of FRP equipment that is new and recently placed into service. 257 • The distance between the FRP equipment and personnel or critical equipment • Substance contained in the vessel is of such a nature that if abruptly released it could threaten the health or safety of personnel • Contains chemicals or is subject to conditions known to degrade or shorten the life of FRP laminates NATIONAL BOARD INSPECTION CODE • Past experience has shown that the service application warrants more frequent internal and external inspections • Insurance or jurisdictional requirements b. FRP equipment should be externally inspected • Once every 2 to 3 years after introduction of process fluid — all findings are to be documented in the equipment inspection file for comparison to future inspection. • If upsets outside the vessel design conditions in the process occur, external inspections shall be performed to ensure equipment integrity. • If prior experience (i.e. if equipment was recently replaced using same material/construction) dictates that inspection frequency other than that listed is acceptable (through previous inspections and records) then the inspection frequency may be altered. One year after the introduction of process fluid to establish any changes due to service and chemical environment. • After the initial first year inspection, subsequent inspections are to be established based on those results. Subsequent inspection intervals shall be documented. It is suggested to document inspections using photographs. • If prior experience (i.e. if equipment was recently replaced using same material/construction) dictates that inspection frequency other than that documented is acceptable, then the inspection frequency may be altered. • If upsets outside the vessel design conditions in the process occur, internal inspections shall be performed to ensure equipment integrity. 9-5820 Previously repaired or altered equipment: a. The following factors should be considered when determining the frequency of inspection for FRP equipment. c. FRP equipment should be internally inspected: • • • The distance between the FRP equipment and personnel or critical equipment • Substance contained in the vessel is of such a nature that if abruptly released it could threaten the health or safety of personnel • Contains chemicals or is subject to conditions known to degrade or shorten the life of FRP laminates • Past experience has shown that the service application warrants more frequent internal and external inspections • Insurance or jurisdictional requirements b. FRP equipment should be externally inspected: Some conditions may exist where entry is prohibited and alternate means of inspection considered. 258 • Annually – all findings and nonfindings are to be documented in the equipment inspection file for comparison to future inspection. APPENDIX 9 — REPAIR, ALTERATION AND INSPECTION OF FIBER-REINFORCED THERMOSETTING PLASTIC PRESSURE EQUIPMENT • • If upsets outside the vessel design conditions in the process occur, external inspections need be performed to ensure equipment integrity. If prior experience (i.e. if equipment was recently replaced using same material/construction) dictates that inspection frequency other than that listed is acceptable (through previous inspections and records) then the inspection frequency may be altered c. FRP equipment should be internally inspected: • One year after the introduction of process fluid to establish any changes due to service and chemical environment • If upsets outside the vessel design conditions in the process occur, internal inspections need be performed to ensure equipment integrity • tographs of the interior inspection Based on the initial first year inspection subsequent inspections are to be established based on those documented results and the results documented. It is suggested to document using pho- • If prior experience (i.e. if equipment was recently replaced using same material/construction) dictates that inspection frequency other than that listed is acceptable (through previous inspections and records) then the inspection frequency may be altered • Some conditions may exist where entry is prohibited and alternate means of inspection must be considered 9-5900 The following pages contain photographs of typical conditions that may exist in inservice FRP vessels and piping. Note: Figures 9-5900-j through 9-5900-u were reprinted with permission of the Copyright Owner. © MATERIALS TECHNOLOGY INSTITUTE, INC. (2002). The captions of the figures were revised by the NBIC Committee. 259 NATIONAL BOARD INSPECTION CODE 260 APPENDIX 9 — REPAIR, ALTERATION AND INSPECTION OF FIBER-REINFORCED THERMOSETTING PLASTIC PRESSURE EQUIPMENT Figure 9-5900-a — Excessive Heat Figure 9-5900-b — Laminate Voids at Overlays 261 NATIONAL BOARD INSPECTION CODE Figure 9-5900-c — HCL Attack Figure 9-5900-d — Blisters 262 APPENDIX 9 — REPAIR, ALTERATION AND INSPECTION OF FIBER-REINFORCED THERMOSETTING PLASTIC PRESSURE EQUIPMENT Figure 9-5900-e — Surface Erosion Figure 9-5900-f — Corrosion/Erosion 263 NATIONAL BOARD INSPECTION CODE Figure 9-5900-g — Cracks Figure 9-5900-h — Corrosion (Loss of Veil) 264 APPENDIX 9 — REPAIR, ALTERATION AND INSPECTION OF FIBER-REINFORCED THERMOSETTING PLASTIC PRESSURE EQUIPMENT Figure 9-5900-i — Shell Fracture Figure 9-5900-j — Concentrated Sulfuric Acid Attack 265 NATIONAL BOARD INSPECTION CODE Figure 9-5900-k — Small Blister and Cracked Veil Figure 9-5900-l — Fiber Prominence 266 APPENDIX 9 — REPAIR, ALTERATION AND INSPECTION OF FIBER-REINFORCED THERMOSETTING PLASTIC PRESSURE EQUIPMENT Figure 9-5900-m — Color Change Figure 9-5900-n — Cut Edge Evaluation 267 NATIONAL BOARD INSPECTION CODE Figure 9-5900-o — Erosion in the Liner Figure 9-5900-p — Cracked Flange 268 APPENDIX 9 — REPAIR, ALTERATION AND INSPECTION OF FIBER-REINFORCED THERMOSETTING PLASTIC PRESSURE EQUIPMENT Figure 9-5900-q — Gouge Figure 9-5900-r — Gusset Crack 269 NATIONAL BOARD INSPECTION CODE Figure 9-5900-s — Cracks at the Knuckle Figure 9-5900-t — Star Craze in Corroded Liner 270 APPENDIX 9 — REPAIR, ALTERATION AND INSPECTION OF FIBER-REINFORCED THERMOSETTING PLASTIC PRESSURE EQUIPMENT Figure 9-5900-u — Sulfuric Acid Attack and Theraml Shock Figure 9-5900-v — Exposed Liner with Air Bubbles 271 NATIONAL BOARD INSPECTION CODE Figure 9-5900-w — Deleminations and Blisters Figure 9-5900-x — Flange Cracking 272 APPENDIX 9 — REPAIR, ALTERATION AND INSPECTION OF FIBER-REINFORCED THERMOSETTING PLASTIC PRESSURE EQUIPMENT Figure 9-5900-y — EPDM Gasket (Over Tongue) Figure 9-5900-z — Incorrect Gusset Attachment 273 NATIONAL BOARD INSPECTION CODE Figure 9-5900-aa — Star Craze Figure 9-5900-bb — Improper Use of Putty 274 APPENDIX 9 — REPAIR, ALTERATION AND INSPECTION OF FIBER-REINFORCED THERMOSETTING PLASTIC PRESSURE EQUIPMENT Figure 9-5900-cc — Cracked Flange 275 NATIONAL BOARD INSPECTION CODE 276 Standard Welding Procedures Appendix A 277 NATIONAL BOARD INSPECTION CODE APPENDIX A — STANDARD WELDING PROCEDURES One or more Standard Welding Procedure Specifications (WPSs) from the following list may be used as an alternative to one or more WPS documents qualified by the organization making the A04 repair, or alteration provided the organization accepts by certification (contained therein) full responsibility for the application of the Standard WPS in conformance with the application as stated in the SWP. When using SWPs, all variables listed on the standard welding procedure are considered essential and, therefore, the repair organization cannot deviate, modify, amend or revise any SWP. Standard welding procedures shall not be used in the same product joint together with other standard welding procedures or other welding procedure specifications qualified by the organization. CARBON STEEL — (P1 MATERIALS) SMAW — Shielded Metal Arc Welding Standard Welding Procedure Specification (WPS) for Shielded Metal Arc Welding of Carbon Steel, (M-1/P-1, Group 1 or 2), 3/16 in. (5 mm) through 3/4 in. (19 mm), in the As-Welded Condition, With Backing. B2.1.001-90 Standard Welding Procedure Specification (WPS) for Shielded Metal Arc Welding of Carbon Steel (M-1/P-1/S-1, Group 1 or 2), 1/8 through 1-1/2 in. Thick, E7018, As-Welded or PWHT Condition. B2.1-1-016-94 Standard Welding Procedure Specification (WPS) for Shielded Metal Arc Welding of Carbon Steel (M-1/P-1/S-1, Group 1 or 2), 1/8 through 1-1/2 in. Thick, E6010, As-Welded or PWHT Condition. B2.1-1-017-94 Standard Welding Procedure Specification (WPS) for Shielded Metal Arc Welding of Carbon Steel (M-1/P-1/S-1, Group 1 or 2), 1/8 through 1-1/2 in. Thick, E6010 (Vertical Uphill) Followed by E7018, As-Welded or PWHT Condition. B2.1-1-022-94 Standard Welding Procedure Specification (WPS) for Shielded Metal Arc B2.1-1-026-94 Welding of Carbon Steel (M-1/P-1/S-1, Group 1 or 2), 1/8 through 1-1/2 in. Thick, E6010 (Vertical Downhill) Followed by E7018, As-Welded or PWHT Condition. Standard Welding Procedure Specification (WPS) for Shielded Metal Arc B2.1-1-201-96 Welding of Carbon Steel (M-1/P-1/S-1, Group 1 or 2) 1/8 through 3/4 in. thick, E6010 (vertical uphill) followed by E7018, As-Welded Condition, Primarily Pipe Application. Standard Welding Procedure Specification (WPS) for Shielded Metal Arc B2.1-1-203-96 Welding of Carbon Steel (M-1/P-1/S-1, Group 1 or 2) 1/8 through 3/4 in. thick, E6010 (vertical uphill), As-Welded Condition, Primarily Pipe Application. 278 APPENDIX A - STANDARD WELDING PROCEDURES Standard Welding Procedure Specification (WPS) for Shielded Metal Arc Welding of Carbon Steel (M-1/P-1/S-1, Group 1 or 2) 1/8 through 3/4 in. thick, E6010 (vertical downhill root with balance vertical uphill), AsWelded Condition, Primarily Pipe Application. B2.1-1-204-96 Standard Welding Procedure Specification (WPS) for Shielded Metal Arc B2.1-1-205-96 Welding of Carbon Steel (M-1/P-1/S-1, Group 1 or 2) 1/8 through 3/4 in. thick, E6010 (vertical uphill) followed by E7018, As-Welded or PWHT Condition, Primarily Pipe Application. Standard Welding Procedure Specification (WPS) for Shielded Metal Arc B2.1-1-206-96 Welding of Carbon Steel (M-1/P-1/S-1, Group 1 or 2) 1/8 through 3/4 in. thick, E6010 (vertical downhill) followed by E7018, As-Welded or PWHT Condition, Primarily Pipe Application. Standard Welding Procedure Specification (WPS) for Shielded Metal Arc B2.1-1-208-96 Welding of Carbon Steel (M-1/P-1/S-1, Group 1 or 2) 1/8 through 3/4 in. thick, E7018, As-Welded or PWHT Condition, Primarily Pipe Application. GTAW — Gas Tungsten Arc Welding Standard Welding Procedure Specification (WPS) for Gas Tungsten Arc Welding of Carbon Steel, (M-1/P-1, Group 1 or 2), 3/16 in. (5 mm) through 7/8 in. (22 mm), in the As-Welded Condition, With or Without Backing. B2.1.002-90 Standard Welding Procedure Specification (WPS) for Gas Tungsten Arc B2.1-1-207-96 Welding of Carbon Steel (M-1/P-1/S-1, Group 1 or 2) 1/8 through 3/4 in. thick, ER70S-2, As-Welded or PWHT Condition, Primarily Pipe Application. Standard Welding Procedure Specification (WPS) for Gas Tungsten Arc Welding (Consumable Insert) of Carbon Steel (M-1/P-1/S-1, Group 1 or 2) 1/8 through 3/4 in. thick, INMs1 and ER70S-2, As-Welded or PWHT Condition, Primarily Pipe Application. B2.1-1-210-96 Standard Welding Procedure Specification (WPS) for Gas Tungsten Arc Welding with Consumable Insert Root of Carbon Steel (M-1/P-1/S-1, Group 1 or 2) 1/8 through 1-1/2 in. Thick, INMs-1, ER70S-2, As-Welded or PWHT Condition, Primarily Pipe Applications. B2.1-1-210:2001 279 NATIONAL BOARD INSPECTION CODE FCAW — Flux Core Arc Welding Standard Welding Procedure Specification (WPS) for Self-Shielded Flux Cored Arc Welding of Carbon Steel (M-1/P-1/S-1, Group 1 or 2), 1/8 through 1-1/2 in. Thick, E71T-8, As-Welded Condition. B2.1-1-018-94 Standard Welding Procedure Specification (WPS) for CO2 Shielded Flux Cored Arc Welding of Carbon Steel (M-1/P-1/S-1, Group 1 or 2), 1/8 through 1-1/2 in. Thick, E70T-1 and E71T-1, As-Welded Condition. B2.1-1-019-94 Standard Welding Procedure Specification (WPS) for 75% Ar/25% CO2 Shielded Flux Cored Arc Welding of Carbon Steel (M-1/P-1/S-1, Group 1 or 2), 1/8 through 1-1/2 in. Thick, E70T-1 and E71T-1, As-Welded or PWHT Condition. B2.1-1-020-94 Standard Welding Procedure (SWP) for Self-Shielded Flux Cored Arc Welding of Carbon Steel (M-1/P-1/S-1, Group 1 or 2), 1/8 through 1/2 in. Thick, E71T-11, As-Welded Condition. B2.1-1-027-1998 Carbon Steel — Combination Processes GTAW/SMAW Standard Welding Procedure Specification (WPS) for Gas Tungsten Arc Welding Followed by Shielded Metal Arc Welding of Carbon Steel (M-1/P-1/S-1, Group 1 or 2), 1/8 through 1-1/2 in. Thick, ER70S-2 and E7018, As-Welded or PWHT Condition. B2.1-1-021-94 Standard Welding Procedure Specification (WPS) for Gas Tungsten Arc Welding followed by Shielded Metal Arc Welding of Carbon Steel (M1/P-1/S-1, Group 1 or 2) 1/8 through 3/4 in. thick, ER70S-2 and E7018, As-Welded or PWHT Condition, Primarily Pipe Application. B2.1-1-209-96 Standard Welding Procedure Specification (WPS) for Gas Tungsten Arc Welding (Consumable Insert) Followed by Shielded Metal Arc Welding of Carbon Steel (M-1/P-1/S-1, Group 1 or 2) 1/8 through 3/4 in. thick, INMs1 and E7018, As-Welded or PWHT Condition, Primarily Pipe Application. B2.1-1-211-96 Standard Welding Procedure Specification (WPS) for Gas Tungsten Arc Welding with Consumable Insert Root Followed by Shielded Metal Arc Welding of Carbon Steel (M-1/P-1/S-1, Group 1 or 2) 1/8 through 1-1/2 in. Thick, INMs-1, ER70S-2 and E7018 As-Welded or PWHT Condition, Primarily Pipe Applications. B2.1-1-211:2001 280 APPENDIX A - STANDARD WELDING PROCEDURES AUSTENITIC STAINLESS STEEL — (P8 MATERIALS) SMAW — Shielded Metal Arc Welding Standard Welding Procedure Specification (WPS) for Shielded Metal Arc Welding of Austenitic Stainless Steel (M-8/P-8/S-8, Group 1), 1/8 through 1-1/2 in. Thick, As-Welded Condition. B2.1-8-023-94 Standard Welding Procedure Specification (WPS) for Shielded Metal Arc Welding of Austenitic Stainless Steel (M-8/P-8/S-8, Group 1), 1/8 through 2-1/2 in. thick, E3XX-XX, As-Welded Condition, Primarily Pipe Application. B2.1-8-213-97 GTAW — Gas Tungsten Arc Welding Standard Welding Procedure Specification (WPS) for Gas Tungsten Arc Welding of Austenitic Stainless Steel (M-8/P-8/S-8, Group 1), 1/8 through 1-1/2 in. Thick, As-Welded Condition. B2.1-8-024-94 Standard Welding Procedure Specification (WPS) for Gas Tungsten Arc Welding of Austenitic Stainless Steel (M-8/P-8/S-8, Group 1), 1/16 through 1-1/2 in. Thick, ER3XX, As-Welded Condition, Primarily Plate and Structural Applications. B2.1-8-024:2001 Standard Welding Procedure Specification (WPS) for Gas Tungsten Arc Welding of Austenitic Stainless Steel (M-8/P-8/S-8, Group 1), 1/8 through 2-1/2 in. thick, ER3XX, As-Welded Condition, Primarily Pipe Application. B2.1-8-212-97 Standard Welding Procedure Specification (WPS) for Gas Tungsten Arc Welding of Austenitic Stainless Steel (M-8/P-8/S-8, Group 1), 1/16 through 1-1/2 in. Thick, ER3XX, As-Welded Condition, Primarily Pipe Applications. B2.1-8-212:2001 Standard Welding Procedure Specification (WPS) for Gas Tungsten Arc Welding With Consumable Insert Root of Austenitic Stainless Steel (M8/P-8/S-8, Group 1), 1/8 through 1-1/2 in. Thick, IN3XX and ER3XX As-Welded Condition, Primarily Pipe Application. B2.1-8-215-2001 281 NATIONAL BOARD INSPECTION CODE Carbon Steel — Combination Processes GTAW/SMAW Standard Welding Procedure Specification (WPS) for Gas Tungsten Arc Welding followed by Shielded Metal Arc Welding of Austenitic Stainless Steel (M-8/P-8/S-8, Group 1), 1/8 through 1-1/2 in. Thick, As-Welded Condition. B2.1-8-025-94 Standard Welding Procedure Specification (WPS) for Gas Tungsten Arc Welding followed by Shielded Metal Arc Welding of Austenitic Stainless Steel (M-8/P-8/S-8, Group 1) 1/8 through 1-1/2 in. Thick, ER3XX and E3XX-XX, As-Welded Condition, Primarily Plate and Structural Applications. B2.1-8-025:2001 Standard Welding Procedure Specification (WPS) for Gas Tungsten Arc Welding Followed by Shielded Metal Arc Welding of Austenitic Stainless Steel (M-8/P-8/S-8, Group 1), 1/8 through 2-1/2 in. thick, ER3XX and E3XX-XX, As-Welded Condition, Primarily Pipe Application. B2.1-8-214-97 Standard Welding Procedure Specification (WPS) for Gas Tungsten Arc Welding Followed by Shielded Metal Arc Welding of Austenitic Stainless Steel (M-8/P-8/S-8, Group 1), 1/8 through 1-1/2 in. Thick, ER3XX and E3XX-XX, As-Welded Condition, Primarily Pipe Applications. B2.1-8-214:2001 Standard Welding Procedure Specification (WPS) for Gas Tungsten Arc Welding With Consumable Insert Followed by Shielded Metal Arc Welding of Austenitic Stainless Steel (M-8/P-8/S-8, Group 1), 1/8 through 1-1/2 in. Thick, IN3XX, ER3XX, and E3XX-XX As-Welded Condition, Primarily Pipe Application. B2.1-8-216-1998 Standard Welding Procedure Specification (WPS) for Gas Tungsten Arc Welding with Consumable Insert Root followed by Shielded Metal Arc Welding of Austenitic Stainless Steel (M-8/P-8/S-8, Group 1), 1/8 through 1-1/2 in. Thick, IN3XX, ER3XX and E3XX-XX As-Welded Condition, Primarily Pipe Applications. B2.1-8-216-2001 COMBINATION CARBON STEEL TO AUSTENITIC STAINLESS STEEL SMAW — Shielded Metal Arc Welding Standard Welding Procedure Specifications (SWPS) for Shielded Metal Arc Welding of Carbon Steel (M-1/P-1/S-1, Groups 1 or 2) to Austenitic Stainless Steel (M-8/P-8/S-8, Group 1), 1/8 through 1-1/2 inch Thick, E309(L)-15, -16, or -17, As-Welded Condition, Primarily Pipe Applications. 282 B2.1-1/8-228:2002 APPENDIX A - STANDARD WELDING PROCEDURES GTAW — Gas Tungsten Arc Welding Standard Welding Procedure Specification (SWPS) for Gas Tungsten B2.1-1/8-227:2002 Arc Welding of Carbon Steel (M-1/P-1/S-1, Groups 1 or 2) to Austentic Stainless Steel (M-8/P-8/S-8, Group 1), 1/16 through 1-1/2 inch Thick, ER309(L), As-Welded Condition, Primarily Pipe Applications. Standard Welding Procedure Specifications (SWPS) for Gas Tungsten Arc Welding with Consumable Insert Root of Carbon Steel (M-1/P-1/S-1, Groups 1 or 2) to Austenitic Stainless Steel (M-8/P-8/ S-8, Group 1), 1/16 through 1-1/2 inch Thick, IN309 and ER309(L), As-Welded Condition, Primarily Pipe Applications. B2.1-1/8-230:2002 Carbon Steel — Combination Processes GTAW/SMAW Standard Welding Procedure Specifications (SWPS) for Gas Tungsten Arc Welding followed by Shielded Metal Arc Welding of Carbon Steel (M-1/P-1/S-1,Groups 1 or 2) to Austenitic Stainless Steel (M-8/P-8/ S-8, Group 1), 1/8 through 1-1/2 inch Thick, ER309(L) and E309(L)-15, -16, or -17, As-Welded Condition, Primarily Pipe Applications. B2.1-1/8-229:2002 Standard Welding Procedure Specifications (SWPS) for Gas Tungsten B2.1-1/8-231:2002 Arc Welding with Consumable Insert Root followed by Shielded Metal Arc Welding of Carbon Steel (M-1/P-1/S-1, Groups 1 or 2) to Austenitic Stainless Steel (M-8/P-8/S-8, Group 1), 1/8 through 1-1/2 inch Thick, IN3009, ER309, and E309-15, -16, or -17 or IN309, ER309(L) and ER309(L)-15, -16, or -17, As-Welded Condition, Primarily Pipe Applications. CHROMIUM MOLYBDENUM STEEL (P4 AND P5A MATERIALS) SMAW — Shielded Metal Arc Welding Standard Welding Procedure Specifications (SWPS) for Shielded Metal Arc Welding of Chromium-Molybdenum Steel (M-4/P-4, Group 1 or 2), E8018-B2, 1/8 through 1/2 in. Thick, As-Welded Condition, 1/8 through 1-1/2 in. Thick, PWHT Condition, Primarily Pipe Applications. B2.1-4-218:1999 Standard Welding Procedure Specifications (SWPS) for Shielded Metal Arc Welding of Chromium-Molybdenum Steel (M-5A/P-5A), E9018-B3, 1/8 through 1/2 in. Thick, As-Welded Condition, 1/8 in. through 1-1/2 in. Thick, PWHT Condition, Primarily Pipe Applications. B2.1-5A-223:1999 283 NATIONAL BOARD INSPECTION CODE GTAW — Gas Tungsten Arc Welding Standard Welding Procedure Specifications (SWPS) for Gas Tungsten Arc Welding of Chromium-Molybdenum Steel (M-4/P-4, Group 1 or 2), ER80S-B2, 1/8 through 1/2 in. Thick, As-Welded Condition, 1/8 through 3/4 in. Thick, PWHT Condition, Primarily Pipe Applications. B2.1-4-217:1999 Standard Welding Procedure Specifications (SWPS) for Gas Tungsten Arc Welding (Consumable Insert Root) of Chromium-Molybdenum Steel (M-4/P-4, Group 1 or 2), E8018-B2, 1/8 through 1/2 in. Thick, As-Welded Condition, 1/8 through 3/4 in. Thick, PWHT Condition, IN515 and ER80S-B2, Primarily Pipe Applications. B2.1-4-220:1999 Standard Welding Procedure Specifications (SWPS) for Gas Tungsten Arc Welding of Chromium-Molybdenum Steel (M-5A/P-5A), ER90SB3, 1/8 through 1/2 in. Thick, As-Welded Condition, 1/8 through 3/4 in. Thick, PWHT Condition, Primarily Pipe Applications. B2.1-5A-222:1999 Standard Welding Procedure Specifications (SWPS) for Gas Tungsten Arc Welding (Consumable Insert Root) of Chromium-Molybdenum Steel (M-5A/P-5A), 1/8 through 1/2 in. Thick, As-Welded Condition, 1/8 through 3/4 in. Thick, PWHT Condition, IN521 and ER90S-B3, Primarily Pipe Applications. B2.1-5A-225:1999 Chromium-Molybdenum Steel Processes GTAW/SMAW Standard Welding Procedure Specifications (SWPS) for Gas Tungsten B2.1-4-219:1999 Arc Welding followed by Shielded Metal Arc Welding of ChromiumMolybdenum Steel (M-4/P-4, Group 1 or 2), 1/8 through 1/2 in. Thick, As-Welded Condition, 1/8 through 1-1/2 in Thick, PWHT Condition, ER80S-B2 and E8018-B2, Primarily Pipe Applications. Standard Welding Procedure Specifications (SWPS) for Gas Tungsten B2.1-4-221:1999 Arc Welding (Consumable Insert Root) followed by Shielded Metal Arc Welding of Chromium-Molybdenum Steel (M-4/P-4, Group 1 or 2), 1/8 through 1/2 in. Thick, As-Welded Condition, 1/8 through 1-1/2 in. Thick, PWHT Condition, IN515, ER80S-B2, and E8018-B2, Primarily Pipe Applications. Standard Welding Procedure Specifications (SWPS) for Gas Tungsten Arc Welded followed by Shielded Metal Arc Welding of ChromiumMolybdenum Steel (M-5A/P-5A), 1/8 through 1/2 in. Thick, As-Welded Condition, 1/8 through 1-1/2 in. Thick, PWHT Condition, ER90S-B3 and E9018-B3, Primarily Pipe Applications. 284 B2.1-5A-224:1999 APPENDIX A - STANDARD WELDING PROCEDURES Standard Welding Procedure Specifications (SWPS) for Gas Tungsten Arc Welding (Consumable Insert Root) followed by Shielded Metal Arc Welding of Chromium-Molybdenum Steel (M-5A/P-5A), 1/8 through 1/2 in. Thick, As-Welded Condition, 1/8 through 1-1/2 in. Thick, PWHT Condition, IN521, ER90S-B3, and E9018-B3, Primarily Pipe Applications. 285 B2.1-5A-226:1999 NATIONAL BOARD INSPECTION CODE 286 Recommended Preheat Temperatures Appendix B 287 NATIONAL BOARD INSPECTION CODE APPENDIX B — RECOMMENDED PREHEAT TEMPERATURES B-1000 Some minimum temperatures for preheating are given below as a general guide. It is cautioned that the preheating temperatures listed do not necessarily ensure satisfactory completion of the welded joint. Requirements for individual materials within the P-Number listing may have preheating requirements more or less restrictive than this general guide. When reference is made in this Appendix to materials by the ASME designation, P-Number and Group Number, the suggestions of this Appendix apply to the applicable materials of the original code of construction, either ASME or other, which conform by chemical composition and mechanical properties to ASME materials having the ASME P-Number and Group Number designations. (See RC-1101) B-2000 b. 50˚F (10˚C) for all other materials in this P-Number. SCOPE 3. P-No. 4 Group Nos. 1 and 2 a. 250˚F (120˚C) for material which has either a specified minimum tensile strength in excess of 60,000 psi (410 MPa) or a thickness at the joint in excess of 1/2 in. (13 mm). b. 50˚F (10˚C) for all other materials in this P-Number. 4. P-No. 5A Group 1 and 5B, Group 1 a. 400˚F (205˚C) for material which has either a specified minimum tensile strength in excess of 60,000 psi (410 MPa) or has both a specified minimum chromium content above 6.0% and thickness at the joint in excess of 1/2 in. (13 mm). MINIMUM TEMPERATURES FOR PREHEATING Thicknesses referenced to are nominal at the weld for the parts to be joined. 1. P-No. 1 Group Nos. 1, 2 and 3 a. 175˚F (79˚C) for material which has both a specified maximum carbon content in excess of 0.30% and a thickness at the joint in excess of 1 in. b. 50˚F (10˚C) for all other materials in this P-Number. 2. P-No. 3 Group Nos. 1, 2 and 3 a. 175˚F (79˚C) for material which has either a specified minimum tensile strength in excess of 70,000 psi (480 MPa) or a thickness at the joint in excess of 5/8 in. (16 mm). b. 300˚F (150˚C) for all other materials in this P-Number. 5. P-No. 6 Group Nos. 1, 2 and 3 400˚F (205˚C) 6. P-No. 7 Group Nos. 1 and 2 None 7. P-No. 8 Group Nos. 1 and 2 None 8. P-No. 9 Group 288 a. 250˚F (120˚C) for P-9A Gr. 1 materials b. 300˚F (150˚C) for P-9B Gr. 1 materials APPENDIX B — RECOMMENDED PREHEAT TEMPERATURES 9. P-No. 10 Group 10. P-No. 11 Group a. 175˚F (79˚C) for P-10A Gr. 1 materials a. P-11A Group Group 1 - None (Note 1) Group 2 - Same as for P-No. 5 (Note 1) Group 3 - Same as for P-No. 5 (Note 1) Group 4 - 250˚F (120˚C) b. 250˚F (120˚C) for P-10B Gr. 2 materials c. 175˚F (79˚C) for P-10C Gr. 3 materials b. P-11B Group Group 1 - Same as for P-No. 3 (Note 1) Group 2 - Same as for P-No. 3 (Note 1) Group 3 - Same as for P-No. 3 (Note 1) Group 4 - Same as for P-No. 3 (Note 1) Group 5 - Same as for P-No. 3 (Note 1) Group 6 - Same as for P-No. 5 (Note 1) Group 7 - Same as for P-No. 5 (Note 1) d. 250˚F (120˚C) for P-10F Gr. 6 materials e. For P-10C Gr. 3 materials, preheat is neither required nor prohibited, and consideration shall be given to the limitation of interpass temperature for various thicknesses to avoid detrimental effects on the mechanical properties of heat treated material. f. For P-10D Gr. 4 and P-10E Gr. 5 materials, 300˚F (150˚C) with interpass temperature maintained between 350˚F and 450˚F (175˚C and 230˚C). Note 1: Consideration shall be given to the limitation of interpass temperature for various thicknesses to avoid detrimental effects on the mechanical properties of heat treated materials. 289 NATIONAL BOARD INSPECTION CODE 290 Historical Boilers Appendix C Note: Part PR and excerpts from Part PFT and Appendix A have been reprinted from ASME 1971 BPVC Section I, by permission of the American Society of Mechanical Engineers. All rights reserved. 291 NATIONAL BOARD INSPECTION CODE APPENDIX C — HISTORICAL BOILERS C-1000 PURPOSE This section provides recommended requirements for the inspection and repair of historical steam boilers. C-1010 e. The inspector may require other examinations to be performed, including but not limited to: 1. An ultrasonic transverse wave examination in two directions at 90° to each other of the longitudinal lap seam for cracks located between or adjacent to rivet holes. SCOPE Historical steam boilers of riveted construction, preserved, restored, or maintained for hobby or demonstration use. C-2000 2. A magnetic particle examination of 100% of the longitudinal seam riveted area, and an ultrasonic (longitudinal wave mode) examination of 10% of the rivets for shear failure. PRE-INSPECTION REQUIREMENT See RB-3120 Internal Inspection of Boilers. 3. An ultrasonic examination (longitudinal wave mode) of all firebox staybolts and rivets. C-2010 4. A liquid penetrant examination. INITIAL INSPECTION The results of examinations and tests shall be documented by an inspector, acceptable to the jurisdiction, who has demonstrated knowledge with historical boilers. The following examinations and tests shall be performed: a. An internal and external visual inspection (See Boiler Inspection Guideline). b. All threaded openings in the boiler shall be inspected. c. Ultrasonic thickness testing and evaluation of all pressure retaining boundaries. Ultrasonic results in areas of generalized thinning (3 in. (75 mm) in diameter or greater) or where grooved thinning is noted (2 in. (50 mm) in length or greater) are to be used in calculating MAWP in accordance with C-8000. d. A hydrostatic pressure test at 1.25 times MAWP, but in no case shall the test pressure be exceeded by more than 6%. 5. Drilling or treppaning of pressureretaining components. C-2020 RECURRING INSPECTION REQUIREMENTS The following examinations and tests shall be performed: a. Annual visual internal and external inspection (See Boiler Inspection Guideline). b. Annual visual inspection of the fusible plugs to determine the condition of the threads in the crown sheet and on the fusible plug. The fusible plugs shall be removed, inspected and confirmed as an ASME Std. plug. c. Annual hydrostatic test at a pressure at least equal to MAWP up to 1.25 times MAWP, but in no case shall the test pressure exceed 1.25 times MAWP by more than 6%. 292 APPENDIX C — HISTORICAL BOILERS d. Every five years ultrasonic thickness testing. valves and the boiler, nor on the discharge pipe between the valve and the atmosphere. e. Additional testing and examination as deemed necessary by the inspector. The piping connection between the boiler and the safety valve shall not be less than the inlet size of the safety valve, and the discharge pipe, if used, shall not be reduced between the safety valve and the point of discharge. C- 2030 SAFETY DEVICES AND CONTROLS Each boiler shall be equipped with the following safety devices and controls. Pressure relief valve(s), gage glasses, try-cocks, fusible plugs, and pressure gages shall be tested during each inspection. C-2031 PRESSURE RELIEF VALVES Pressure relief valve(s) shall be National Board capacity certified. Pressure relief valve(s) shall be sealed by an ASME “V” Stamp assembler or NB “VR” repair firm. C-2032 GAGE GLASS The gage glass shall be fit with a guard to protect the gage glass. The gage glass shall indicate the minimum safe operating water level. The gage glass shall be provided with a drain valve or petcock, piped to a safe location. The gage glass shall be fully operational. C-2030 TRY-COCKS The required pressure relief valve capacity in pounds per hour shall be calculated by boiler heating surface area and type of fuel used. Excessive pressure relief valve capacity should be avoided. (Only heating surface area above the grates to be used.) Try-cocks shall be correctly located in reference to the minimum required water level. Minimum pounds of steam per hour per square foot of heating surface (kg/hr/sq. 0.3 m). All boilers shall have a fusible plug unless equipped and operated with automatic controls. Boiler Heating Surface Firetube Boiler Watertube Boiler hand fired 5 6 stoker fired 7 8 oil, gas or pulverized fuel fired 8 10 Try-cocks shall be fully operational C-2034 FUSIBLE PLUG All fusible plugs shall be constructed to meet the requirements of the ASME Code, and indicated as such by the ASME marking on the filler material. Fireside fusible plugs must protrude a minimum of one inch into the water. Pressure relief valve(s) shall have a test lever. No valve of any description shall be placed between the required pressure relief valve or Waterside fusible plugs may not protrude into the fire area more than one inch. Fusible plugs shall not be refilled. 293 NATIONAL BOARD INSPECTION CODE C-2035 PRESSURE GAGE C-3000 Tested and proven accurate at the time of the annual pressure test. Siphon, or water seal, shall be installed between pressure gage and boiler. If a valve is installed between the gage and the boiler, the valve shall indicate the open position or be wired open. REPLACEMENTS The installation date should be stamped or stenciled on all replaced boiler piping. Alternatively, the installation date may be documented in permanent boiler records. C-4000 MAXIMUM ALLOWABLE WORKING PRESSURE All boiler piping and fittings shall meet the following requirements: The maximum allowable working pressure of a boiler shall be determined by computing the strength of each component to find the weakest point. The strength of the weakest component and the factor of safety allowed by these rules shall determine the maximum allowable working pressure. The following shall be used to compute the strength of each boiler component. a. Threaded openings shall follow accepted standard piping practices. C-4010 C-2040 APPURTENANCES C-2041 PIPING AND FITTINGS b. Schedule 80, black pipe (SA-53 B or SA-106 B) shall be used from the boiler to the first valve. c. All steam piping components shall be used in the manner for which they were designed and shall not exceed manufacturer’s pressure rating. d. The boiler shall be equipped with two means of supplying feedwater while the boiler is under pressure. Pumped water shall be heated. e. The blowdown line shall be plugged off during the time the boiler is operating on display, or piped to a safe point of discharge. f. STRENGTH In calculating the MAWP, when the tensile strength of the steel or wrought iron is known, that value shall be used. When the tensile strength of the steel or wrought iron is not known, the values to be used are 55,000 psi (380 MPa) for steel and 45,000 psi (310 MPa) for wrought iron. Original steel stamp marks, original material certifications, or current laboratory tests are acceptable sources for verification of tensile strength. Catalogs and advertising literature are not acceptable sources for tensile strength values. In computing the ultimate strength of rivets in shear, the following values in pounds per square inch of the cross-sectional area of the rivet shanks shall be used: All piping shall be properly supported. Iron rivets in single shear ...........38,000 (260 MPa) Iron rivets in double shear .........76,000 (520 MPa) Steel rivets in single shear ..........44,000 (300 MPa) Steel rivets in double shear ........88,000 (600 MPa) 294 APPENDIX C — HISTORICAL BOILERS The resistance to crushing of mild steel shall be taken as 95,000 psi (655 MPa) of cross-sectional area. C-4020 RIVETS When the diameter of the rivet holes in the longitudinal joints of a boiler is not known, the diameter of rivets, after driving, may be ascertained from the table below. Thickness of Plate, inches (mm) 1/4 (6) 9/32 (7) 5/16 (8) 11/32 (9) 3/8 (10) Diameter of Rivet after Driving, inches (mm) 11/16 11/16 (17) (17) 3/4 (19) 3/4 (19) 13/16 13/16 (21) (21) The maximum allowable working pressure for stayed flat plates and those parts which, by these rules, require staying as flat plates with stays or staybolts of uniform diameter symmetrically spaced, shall be calculated using the following formulas: t2 x TS x C FS x p2 = maximum allowable working pressure (MAWP), psi 13/32 (10) 15/32 1/2 (12) (13) 9/16 (14) Diameter of 15/16 15/16 15/16 1-1/16 Rivet after (24) (24) (24) (27) Driving, inches (mm) BRACED AND STAYED SURFACES (REQUIRED BRACE OR STAYBOLT DIAMETER) The MAWP based on the net minimum diameters of staybolts shall be computed using the following formula: π x d2 x TS Thickness of 7/16 Plate, inches (11) (mm) 5/8 (16) FS x 4 x p2 = maximum allowable working pressure (MAWP), psi The “d” in the formula refers to the diameter A04 of the staybolt at the base of the threads or the smallest diameter as specified in ASME Section I, Pg-49.2, and “TS” in the formula refers to the ultimate tensile strength of the staybolt material. For stayed curved plates, the ratio between TS/FS in the formula shall not exceed 7500 psi as referenced in ASME Section I, PFT 23.3. 1-1/16 (27) CYLINDRICAL COMPONENTS The maximum allowable working pressure of cylindrical components under internal pressure shall be determined by the strength of weakest course computed from the thickness of the plate, the tensile strength of the plate, the efficiency of the longitudinal joint, the inside diameter of weakest course, and the factor of safety allowed by these rules using the following formula: TS x t x E STAYED SURFACES C-4050 Sizes of Rivets Based on Plate Thickness C-4030 C-4040 C-4060 CONSTRUCTION CODE In order to address the many pressure-related components and features of construction encountered in firetube boilers, a reprint of the 1971 Edition of Section I of ASME Boiler Code, Part PFT is provided. = maximum allowable working pressure (MAWP), psi R x FS 295 NATIONAL BOARD INSPECTION CODE C-4070 NOMENCLATURE The nomenclature for the terms used in the above equations is: C = 2.1 for welded stays or stays screwed through plates not over 7/16 in. (11 mm) in thickness with ends riveted over C = 2.2 for welded stays or stays screwed through plates over 7/16 in. (11 mm) in thickness with ends riveted over C = 2.5 for stays screwed through plates and fitted with single nuts outside of plate, or with inside and outside nuts, omitting washers C = 2.8 for stays with heads not less than 1.3 times the diameter of the stays screwed through plates, or made a taper fit and having the heads formed on the stays before installing them and not riveted over, said heads being made to have true bearing on the plate C = 3.2 for stays fitted with inside and outside nuts and outside washers where the diameter of washers is not less than 0.4p and thickness not less than t. Note: the ends of stays fitted with nuts shall not be exposed to the direct radiant heat of the fire. d = diameter of staybolt over the threads, in. E = efficiency of the longitudinal joint The following is a table of efficiencies which are the average for the different types of joints. Type of Riveting Lap single double triple quadruple 58 74 Note: The efficiency of a particular joint depends upon the strength of the plate and rivet, thickness of the plates and the diameter of the rivets. The 1971 Edition of Section I of the ASME Code, Appendix A-1 through A-7, provides a method for calculating a specific joint efficiency which may be used with the concurrence of the jurisdiction. FS = 5 (A jurisdiction may mandate a higher factor of safety or permit a lower factor of safety, but in no case may the factor of safety be less than 4) p = maximum pitch measured between straight lines passing through the centers of the staybolts in the different rows, which lines may be horizontal, vertical or inclined, in. R = inside radius of the weakest course of shell or drum, in. TS = ultimate tensile strength of shell plates, psi (MPa) t = minimum thickness of shell plate in the weakest course, in. (mm) C-5000 LIMITATIONS The maximum allowable working pressure shall be the lesser of that calculated by C8000 or the MAWP established by the original manufacturer. The shell or drum of a boiler in which a typical “lap seam crack” extending parallel to the longitudinal joint and located either between or adjacent to rivet holes, is discovered along a longitudinal riveted joint for either butt or lap joint shall be permanently discontinued for use under steam pressure. Butt C-6000 82 88 94 REPAIRS Repairs to boilers of historical nature should be performed with consideration towards preserving the authenticity of original design, while at the same time ensuring that the boiler is safe to operate at the pressure allowed by C-8000. 296 APPENDIX C — HISTORICAL BOILERS C-6010 CONSTRUCTION STANDARDS Repairs shall conform to the requirements of the original construction standard insofar as possible. If the original construction standard is unknown or unavailable, the boiler shall be considered a boiler of locomotive design as described in Appendix 3, and subject to the construction standard most applicable to the boiler design. The construction standard selected for the repair must meet the approval of the jurisdiction. C-6020 ACCREDITATION Organizations performing welded repairs shall be accredited as described in Part RA. Organizations performing non-welded repairs shall be otherwise acceptable to the jurisdiction by having demonstrated competency in the repair of boilers of locomotive design. C-6030 C-6050 REPLACEMENT PARTS Replacement pressure parts formed by casting, forging, or die forming, and on which no welding has been performed, shall be supplied as material. Such parts shall be marked with the material identification required by the construction standard used for the repair. Replacement pressure parts fabricated by welding shall be manufactured by an organization certified as required by the construction WELDED REPAIR INSPECTION Prior to commencing any welded repairs to the pressure boundaries of historic boilers, the repair organization shall obtain an Inspector’s approval of the proposed repair. The Inspector shall be an employee of either a jurisdiction, as defined in Appendix 4, or of the Authorized Inspection Agency contracted by the repair organization. The Inspector shall assure the repairs are performed in accordance with the approved construction standard, and shall witness any nondestructive or pressure testing of the completed repair. C-6060 MATERIALS Materials used in making repairs shall conform to the original construction standard, if known, or to a construction standard acceptable to the jurisdiction. Carbon or alloy steels having a carbon content greater than 0.35% shall not be welded. The repair organization is responsible for verifying identification of existing and replacement materials. C-6040 standard used for the repair. Where there is no manufacturer prepared to supply parts fabricated by welding, an organization accredited as described in Part RA may fabricate the part with the approval of the jurisdiction. WELDING Welding shall be performed in accordance with the requirements of the approved construction standard in consultation with the inspector identified in C-4000. A repair organization accredited as described in Part RA may use the Standard Welding Procedure Specifications shown in Appendix A, as applicable. Welders shall be qualified for the welding processes used. Qualification shall be in accordance with the approved construction standard, or Section IX of the ASME Code. C-6070 HEAT TREATMENT Preheating may be used to assist in completion of the welded joint. Consideration should be given to the percentage of carbon content and to the thickness of the original boiler materials. Preheat temperatures shall be specified by the welding procedure specification being used. 297 NATIONAL BOARD INSPECTION CODE Postweld heat treatment shall be performed as required by the accepted construction standard, in accordance with written procedures. Welded repairs at or near riveted seams requiring preheat or postweld heat treatment shall be carefully made in order to prevent loosening in the riveted seams, especially when localized heat treatment is used. Alternative postweld heat treatment methods may be used with the inspector’s approval. Welding methods which may be used as alternatives to postweld heat treatment are described in Part RD. C-6080 Heating Surface Design Pressure Current Operating Pressure Inspector Smoke Box 1. Front Tube Sheet a. Check condition of sheet and thickness around handhole openings. b. Check condition of threaded openings and plugs. c. Check condition of rivets between sheet and shell. NONDESTRUCTIVE EXAMINATION The Inspector may require nondestructive examination (RT, PT, MT, UT, VT) as necessary to ensure satisfactory welded repairs have been accomplished. 2. Tubes C-6090 3. Check condition of smoke box shell (especially around lower surfaces). DOCUMENTATION Organizations performing repairs to historic boilers shall document the repair as required by the jurisdiction. a. Are tubes beaded? b. Are there signs of leakage? 4. Check inside condition of barrel and O.D. of tubes. Permanent documentation detailing repairs, inspections, etc. should be retained by the owner. 5. Check back side of tube sheet (especially area in contact with handhole gasket and area where tube sheet joins barrel). BOILER INSPECTION GUIDELINE 6. Check tube sheet supports (through stays, supports or strong backs). Owner Location Make Year Engine No. 7. Check inside rivet heads on lap or buttstrap joints. 8. Check front bolster (front axle) attachment points inside shell. Barrel (shell) 1. Check front bolster attachment points on outside of shell. 298 APPENDIX C — HISTORICAL BOILERS 2. Check condition of tube sheet rivets on outside of shell. 5. Check external shapes or contours that do not appear normal. 3. Check condition of threaded openings and plugs in openings. 6. Check for seepage around staybolt heads. 4. Check radius rod attachment point. 7. Check condition of staybolt heads. 5. Check attachment points of studs, castings, brackets, accessories, etc. 8. Check condition of threaded openings. 6. Check plumbing openings on shell (feedwater nozzles, steam take off, water column, etc.). 7. Check handhole openings in shell. 9. Check internal surfaces (cracks, pits, material thickness). 10. Check staybolt thickness and condition. 11. Check for scale and mud buildup in waterlegs. 8. Lap seam or buttstrap a. Check for leakage around seams or joint rivets. b. Confirm joint efficiency based on number of rows of rivets and type of joint. 12. Check for buildup of dirt and grease between or behind attaching brackets such as wing sheets. 13. a. Dry bottom boilers 1. Check seams at bottom of waterlegs in ash pan area. 9. Identify and check any external contour that does not appear normal. 2. Do you need to remove ash pans and grates to observe above seams? 10. Jacket 3. Check condition of grate support brackets. a. Does jacket cover any critical areas or make them difficult to observe? b. Wet bottom boilers b. Is barrel pitted or corroded under jacket? 1. Check ash pan area for pits and staybolt head condition. Wrapper Sheet 2. Check inside bottom of wrapper and staybolt condition. 1. Check handhole openings (material thickness, gasket area, etc.). 3. Check condition of lap seam in wrapper. 2. Check for seepage around attachment points (wing sheets, axle supports, etc.). 3. Check condition of seams joining wrapper to throat sheet and rear head. 4. Check condition of seams joining throat sheet to barrel. 4. Check condition of ash pan drain tube if present. 14. Check for presence and condition of blowdown valve. 299 NATIONAL BOARD INSPECTION CODE Dome e. Does it have a try lever? 1. Check for presence and condition of drainback holes in shell. f. 2. Check condition of main line shutoff valve. 3. Check condition of plumbing on mainstream line and on dome. 4. Check condition of dome seams and seams between dome and boiler shell. a. Is seepage present? Is it sealed with a factory seal? Water Column and Water Glass 1. Is water glass calibrated to level of crown sheet? 2. Check condition of try-cock valves and blowdown valves on column and glass. 3. Check condition of glass (cracks or scratches). 4. Are there leaks around the water glass gaskets? b. Can interior seams be observed? 5. Check for presence and condition of pressure gage. a. Is there a siphon and what is its condition? b. Is the gage readable from the operator’s position? c. Has the gage been calibrated or checked against another gage? d. If a shutoff valve is present, its handle shall indicate open position, or the handle shall be wired open. 6. Check for presence and condition of safety valve. Firebox 1. Check for bulges or abnormal shapes (What caused them?). 2. Check seams around fire door. 3. Check for sediment buildup over fire door opening rear head. 4. Check for sediment buildup over peephole opening in wrapper sheet (where applicable). 5. Check condition of fusible plug. (Must be removed for observation.) a. Is it an ASME plug? a. Does it have its own inlet/outlet piping with no possibility of closure? b. Check condition of top surface. (May need to brush it off.) b. Check that the inlet pipe size is not smaller than the valve inlet size. 6. When fusible plug is removed, check crown sheet thickness at that location and thread condition. c. Check that the outlet pipe size is not smaller than the valve outlet size. d. Is it a National Board capacity certified, ASME “V”/NB “VR” stamped valve of proper pressure and capacity rating for the boiler heating surface? 7. Fireside fusible plug must protrude a minimum of 1 in. (25 mm) into water. 8. Waterside fusible plug may not protrude into fire area of more than 1 in. (25 mm). 300 APPENDIX C — HISTORICAL BOILERS 9. Water glass calibration can only be done when crown sheet and fusible plug can be seen and measured. (A recommended minimum water level may be determined as follows: With engine sitting on level ground and water just observable at the bottom of the glass, the crown sheet should be covered by a minimum of at least 2-1/2 in. plus on a full-size boiler. 10. Check staybolt condition, especially near top surface of crown sheet. 11. Check through stays, strong backs, knee braces, etc. on rear head. 12. Check handhole openings, threaded openings and plugs in rear head. 13. Check condition of rear tube sheet, and check if rear end of tubes are beaded. 14. Check condition of staybolt heads inside fire box. 15. Check condition or design of crown sheet. Is it flat-topped or able to trap water? External Plumbing 8. Fittings dates are to be stamped, stenciled or recorded on boiler records. 9. 20-year life on piping except for main steam line which shall be evaluated as to life. Ultrasonic Testing (Every fifth year) Hydrostatic Pressure Test (Annually) 1. Hydrostatic pressure test should be between maximum allowable working pressure and 1.25 times maximum allowable working pressure with water temperature at 60° to 120° F (16° to 50° C). 2. An accurate gage with proven accuracy shall be used when hydrostatically pressure testing a boiler. The engine gage shall be calibrated at this time. 3. Safety valve may be checked against test gage and/or engine gage. (Test should only be performed at a pressure greater than 75% of the stamped set pressure of the valve or the safety valve or lifting lever may be damaged.) 1. Is black pipe (as opposed to galvanized) used throughout? 2. Check for use of Schedule 80 black pipe required between boiler and first valve. 3. Are fittings of proper pressure rating for operating pressure? 4. Are isolation valves present to shut off individual system lines? 5. Are two separate feedwater systems present and operable? 6. Check plumbing for frost damage. 7. Are plumbing support brackets present where needed? 301 NATIONAL BOARD INSPECTION CODE PART PR — REQUIREMENTS FOR BOILERS FABRICATED BY RIVETING GENERAL PR-11 PR-1 In computing the ultimate strength of rivets in shear, the values given in Table PG-23.4 in pounds per square inch of the cross-sectional area of the rivet shank shall be used. SCOPE The rules in Part PR are applicable to boilers and parts thereof that are fabricated by riveting and shall be used in conjunction with the general requirements in Part PG as well as with the specific requirements in the applicable Parts of this Section that pertain to the type of boiler under construction. MATERIALS PR-5 GENERAL Materials entering into the construction of riveted boilers shall comply with the requirements for materials given in PG-5 through PG-14. DESIGN PR-9 GENERAL The rules in the following paragraphs apply specifically to the design of boilers and parts thereof that are fabricated by riveting and shall be used in conjunction with the general requirements for Design in Part PG as well as with the specific requirements for Design in the applicable Parts of this Section that pertain to the type of boiler under consideration. PR-10 STRENGTH OF PLATES In determining the maximum allowable working pressure, the maximum allowable working stress in Table PG-23.1 shall be used in the computations. PR-12 STRENGTH OF RIVETS CRUSHING STRENGTH OF PLATES The resistance to crushing of steel plate in pounds per square inch of cross-sectional area shall be taken from Table PG-23.5. PR-14 THICKNESS OF BUTTSTRAPS The minimum thickness of buttstraps for double-strap joints shall be as given in Table PR-14 in which the required thickness of the shell is that obtained by the rules given in PG-27.2 employing a value of E corresponding to the efficiency of the buttstrap joint. Intermediate values shall be determined by interpolation. Where the required thickness of the plate exceeds 1-1/2 in., the thickness of the buttstraps shall be not less than two-thirds of the required thickness of the plate. In no case shall either of the buttstraps have a lesser thickness than one-half the actual thickness of the plate. PR-15 JOINT EFFICIENCY The efficiency of a joint is the ratio which the strength of the joint bears to the strength of the solid plate. In the case of a riveted joint this is determined by calculating the breaking strength of a unit section of the joint, considering each possible mode of failure separately, and dividing the lowest result by the breaking strength of the solid plate of a length equal to that of the section considered (see A-1 through A-7 for detailed methods and examples). 302 APPENDIX C — HISTORICAL BOILERS PR-16 LONGITUDINAL JOINTS 16.1 The riveted longitudinal joints of a shell or drum which exceeds 36 in. in diameter shall be of butt- and double-strap construction. This rule does not apply to the portion of a boiler shell which is staybolted to the firebox sheet. to resist the total longitudinal force acting on the joint with a factor of safety of 5. The total longitudinal force is determined by the following formula: F = 3.14R2P where, F = total longitudinal force, pounds R = radius of the circular area acted on by the pressure in producing the total longitudinal force on the joint, inches P = pressure, pounds per square inch 16.2 The longitudinal joints of a shell or drum which does not exceed 36 in. in diameter may be of lap-riveted construction, but the maximum allowable working pressure shall not exceed 100 psi. 17.2 When 50 percent or more of the total force as described in PR-17.1 is relieved by the effect of tubes or through stays, in consequence of the reduction of the area acted on by the pressure and the holding power of the tubes and stays, the strength of the circumferential joints shall be at least 70 percent of that required by PR-17.1. TABLE PR-14 — Minimum Thickness Of Buttstraps Required Thickness of Steel Plate, in. Minimum Thickness of Buttstraps, in. 1/4 9/32 5/16 11/32 3/8 13/32 1/4 1/4 1/4 1/4 5/16 5/16 7/16 15/32 1/2 17/32 9/16 5/8 3/8 3/8 7/16 7/16 7/16 1/2 3/4 7/8 1 1-1/8 1-1/4 1-1/2 1/2 5/8 11/16 3/4 7/8 1 PR-20 TRANSVERSE PITCH (BACK PITCH) OF ROWS OF RIVETS 20.1 For longitudinal joints the distance between the centerlines of any two adjacent rows of rivets, or the “back pitch” measured at right angles to the direction of the joint, shall have the following minimum values: 20.1.1 If P/d is 4 or less, the minimum value shall be 2d. 20.1.2 If P/d is over 4, the minimum value shall be: 2d + 0.1 (P - 4d) PR-17 CIRCUMFERENTIAL JOINTS 17.1 The strength of a riveted circumferential joint of a boiler, the heads of which are not stayed by tubes or through-stays, shall be sufficient, considering all methods of failure, 303 where, P = pitch of rivets in outer row where a rivet in the inner row comes midway between two rivets in the outer row, inches NATIONAL BOARD INSPECTION CODE P = pitch of rivets in the outer row less pitch of rivets in the inner row where two rivets in the inner row come between two rivets in the outer row, inches (it is here assumed that the joints are the usual construction where the rivets are symmetrically spaced) d = diameter of the rivet holes, inches 20.2 The back pitch of rivets in circumferential joints may be less than that called for by the above formulas provided the ligaments between rivets in a circumferential direction, as well as those in a diagonal direction as determined by the rules in PG-52, are sufficient to withstand the stress due to pressure, together with any stress due to weight components in support of boiler structure, with a factor of safety of 5. 20.3 The back pitch of rivets shall be measured either on the flat plate before rolling, or on the median line after rolling, and the back pitch as there measured shall govern the locations of rivet holes in the buttstraps. 20.4 The distance between any two rows of rivets in a circumferential joint or back pitch shall be not less than 1.75d. PR-21 PREPARATION OF PLATE EDGES The plate edge shall be beveled to an angle not sharper than 70 deg. to the plane of the plate and as near thereto as practicable. PR-22 EDGE DISTANCE 22.1 On longitudinal joints of all types of boilers and on circumferential joints of drums having heads which are not supported by tubes or through-stays, the distance from the centers of rivet holes to the edges of the plates, except rivet holes in the ends of buttstraps, shall be not less than 1-1/2 and not more than 1-3/4 times the diameter of the rivet holes; this distance to be measured from the center of the rivet holes to the caulking edge of the plate before caulking. 22.2 The distance from the centers of rivet holes of circumferential joints to the edges of the plate in boilers having heads which are supported by tubes or through-stays shall be not less than 1-1/4 times the diameter of the rivet holes. PR-23 RIVETED CONNECTIONS Attachment by riveting shall be in accordance with the following requirements: 23.1 Openings for nozzles and other connections shall be far enough away from any main riveted joint so that the joint and the opening reinforcement plates do not interfere with one another. 23.2 Welded connections which require postweld heat treatment and which are attached to vessels having seams of riveted construction shall be fabricated and stress relieved prior to the making up or attachment of the courses by riveting. If they do not require postweld heat treatment and are attached after riveting, the welds shall be located at a distance from the riveted seam at least equal to the outside diameter of the attachment weld plus 4 times the thickness of the shell plate. 23.3 Openings for pipe connections to vessels having riveted joints may be made by inserting pipe couplings or similar devices, not exceeding 3 in. pipe size, in the shell or heads and securing them by welding, provided the welding is performed by welders or welding operators who have been qualified under the provisions of Section IX of the Code for the welding position and type of joint used. 23.4 For nozzle fittings having a bolting flange and an integral flange for riveting, the thick- 304 APPENDIX C — HISTORICAL BOILERS ness of the flange attached to the pressure vessel shall not be less than the thickness of the neck of the fitting. 23.5 The strength of rivets in tension in a flanged frame or ring riveted to the outside of a vessel shall be at least equal to that required to resist the load due to the maximum allowable working pressure with a factor of safety of 5 computed as follows: 23.5.1 For outside caulking the load shall be equal to the area bounded by the outside caulking multiplied by the maximum allowable working pressure. 23.5.2 For inside caulking (and with no outside caulking) the load shall be equal to the area bounded by the inside caulking multiplied by the maximum allowable working pressure. 23.6 The rivets attaching nozzles shall be so spaced as to avoid the possibility of the shell plate or the nozzle flange failing by tearing around through the rivet holes. An example illustrating the method of calculations is given in A-70. PR-25 REINFORCEMENT OF OPENINGS 25.1 The area of reinforcement shall be calculated by the rules in PG-32 through PG-39. 25.2 In applying reinforcement plates to the drums of watertube boilers to strengthen the shell where the tubes enter, they shall be riveted to the shell, and where outside caulking is used, the tube shall be expanded into the inner and outer plates so that the rivets and tubes will hold the plates together in accordance with the rules for stayed surfaces. Where a reinforcing plate is inside the steam drum, it is the inner plate; where it is outside and there is no inner reinforcing plate, the unreinforced shell of the drum is the inner plate. 25.3 The spacing of the rivets with respect to the tubes shall conform to PG-46 for stayed surfaces, using a value of 2.5 for C, and shall be based on a unit pressure equal to the pressure that can be carried by the inner plate with a factor of safety of 5. 25.4 The tension in rivets and tubes shall conform to PFT-27 and PFT-38. 25.5 The combined drum shell and reinforcing plate or plates, and riveted connections, shall have a factor of safety of not less than 5 in the ligaments when calculated in accordance with PG-52. When reinforcing plates or buttstraps are exposed to flame or gas of the equivalent temperature, the joints shall be protected therefrom. FABRICATION PR-30 GENERAL The rules in the following paragraphs apply specifically to the fabrication of the boilers and parts thereof that are fabricated by riveting and shall be used in conjunction with the general requirements for Fabrication in Part PG as well as with the specific requirements for Fabrication in the applicable Parts of this Section that pertain to the type of boiler under construction. PR-31 BUTTSTRAPS 31.1 Buttstraps shall be rolled or formed by pressure, not blows to the curvature of the shell with which they are to be used. 31.2 The ends of inner buttstraps of riveted buttstrap longitudinal joints may be fusion welded to the edges of heads or of the adjoining shell plate, or to circumferential buttstraps for tightness, provided the carbon content in the steel does not exceed 0.35 percent. When the buttstrap of a longitudinal joint does not 305 NATIONAL BOARD INSPECTION CODE extend the full length of the shell plates, as shown in Figure PR-31, the abutting edges of the shell plate may be welded provided the distance from the end of the buttstrap to the edge of the flange of the head or adjacent shell plate is not greater than 2-1/2 in. shows red in the daylight. Barrel pins fitting the holes and tack bolts to hold the plates firmly together shall be used. A rivet shall be driven on each side of each tack bolt before removing the tack bolt. PR-32 40.1 The caulking edges of plates, buttstraps, and heads shall be beveled to an angle not sharper than 70 deg. to the plane of the plate, and as near thereof as practicable. Every portion of the unfinished surfaces of the caulking edges of plates, buttstrap and heads shall be planed, milled, or chipped to a depth of not less than one-fourth of the thickness of the material, but in no case less than 1/8 in. Caulking shall be done with a tool of such form that there is no danger of scoring or damaging the plate underneath the caulking edge, or splitting the caulked sheet. RIVET HOLES All holes for rivets in plates, buttstraps, heads, stays and lugs shall be drilled; or they may be punched at least 1/8 in. less than full diameter for material not over 5/16 in. in thickness and at least 1/4 in. less than full diameter for material over 5/16 in. Such holes shall not be punched in material more than 5/8 in. in thickness. For final drilling or reaming the hole to full diameter, the parts shall be firmly bolted in position by tack bolts. The finished holes must be true, clean and concentric. PR-37 ASSEMBLY OF JOINTS After drilling or reaming rivet holes the plates and buttstraps of longitudinal joints shall be separated, the burrs and chips removed, the plates and buttstraps reassembled metal-tometal with barrel pins fitting the holes, and with tack bolts. PR-39 PR-40 JOINT TIGHTNESS 40.2 Fusion welding may be used to seal the calking edges of circumferential-riveted lap joints of power boilers provided the plates do not exceed 0.35 percent carbon and their thickness is at least 1/8 in. more than that required for a seamless shell of the same diameter, same working pressure, and same grade of material. 40.3 Seal welding may be used on nozzles and their reinforcing plates under the same conditions. On unstaying dished heads, seal welding shall not be applied closer than 1/2 FIGURE PR-31 — Allowable Welding Of Plate Edges At Ends Of Buttstraps RIVETING 39.1 Rivets shall be of sufficient length to completely fill the rivet holes and form heads at least equal in strength to the bodies of the rivets. Forms of finished rivet heads that will be acceptable are shown in ANSI B18.4-1966. 39.2 Rivets shall be so driven as to fill the holes preferably by a machine which maintains the pressure until no part of the head 306 1”max 22 W Welded APPENDIX C — HISTORICAL BOILERS in. to the point of tangency of the knuckle of the flange. Seal welding may be applied only when the weld metal is deposited in single layer having a throat thickness of not less than 3/16 in., nor more than 5/16 in. The heat from welding shall not distort the plate or loosen the rivets in such a manner as to break the initial bond effected in the riveted joint. After seal welding, the vessel shall be resubjected to the prescribed hydrostatic test. 40.4 The inner buttstraps in locomotive-type boilers may be seal welded, provided the carbon content of the plates does not exceed 0.35 percent and the weld metal is deposited in a single layer having a weld size not greater than 3/8 in. INSPECTION AND TESTS PR-50 GENERAL At least two inspections shall be made of riveted construction (one before reaming rivet holes and one at the hydrostatic test) and, at the option of the inspector, at such other stages of the work as he may designate. 307 NATIONAL BOARD INSPECTION CODE PART PFT — REQUIREMENTS FOR FIRETUBE BOILERS GENERAL PFT-9 PFT -1 9.1 Plates The minimum thicknesses of shell plates, and dome plates after flanging, shall be as follows: GENERAL The rules in Part PFT are applicable to firetube boilers and parts thereof and shall be used in conjunction with the general requirements in Part PG as well as with the specific requirements in the applicable Parts of this Section which apply to the method of fabrication used. MATERIALS PFT-5 Diameter of Shell Minimum Thickness 36 in. or under Over 36 to 54 in. Over 54 to 72 in. Over 72 in. 1/4 in. 5/16 in 3/8 in. 1/2 in. 9.2.1 Except as otherwise provided in PFT-9.2.2, the minimum thickness of tube sheets for firetube boilers shall be as follows: GENERAL 5.1 Materials used in the construction of pressure parts for firetube boilers shall conform to one of the specifications given in Section II of the Code and shall be limited to those for which allowable stress values are given in Table PG-23 or as otherwise specifically permitted in Parts PG and PFT. 5.2 Waterleg and doorframe rings of vertical firetube boilers and of locomotive and other type boilers shall be of wrought iron or steel, or cast steel as designed in the Specification SA-216. The ogee or other flanged construction may be used as a substitute in any case. Diameter of Tube Sheet Minimum Thickness 42 in. or under Over 42 to 54 in. Over 54 to 72 in. Over 72 in. 3/8 in. 7/16 in. 1/2 in. 9/16 in. 9.2.2 Tube sheets with a straight flange longer than 1-1/2 times the tube sheet thickness, when butt-welded to the shell of a firetube boiler, shall have a minimum thickness as specified in PFT-9.2.1 but in no case shall be less than 0.75 times the required shell thickness, based on the maximum allowable working pressure. DESIGN PFT-8 MINIMUM THICKNESS GENERAL The rules in the following paragraphs apply specifically to the design of firetube boilers and parts thereof and shall be used in conjunction with the general requirements of Design in Part PG as well as with the specific requirements for Design in the applicable Parts of this Section which apply to the method of fabrication used. PFT-10 SHELL JOINTS 10.1 Welded Joints Welded longitudinal and circumferential joints of a shell or drum shall comply with the rules in Part PW. 308 APPENDIX C — HISTORICAL BOILERS 10.2 Riveted Longitudinal Joints material. Such seal welding shall not be applied until after the boiler is made tight as evidenced by the regular hydrostatic pressure test prescribed in PG-99. 10.2.1 The longitudinal joints of horizontal-return tubular boilers shall be located above the fire line of the setting. 10.2.2 In horizontal-return tubular boilers of riveted construction, no course shall be over 12 ft. long. 10.2.3 The inner buttstraps in locomotivetype boilers may be seal welded, provided the carbon content of the plates does not exceed 0.35% and the weld metal is deposited in a single layer having a weld size not greater than 3/8 in. 10.3 Riveted Circumferential Joints PFT-11 ATTACHMENT OF HEADS AND TUBE SHEETS Flat heads and tube sheets of firetube boilers shall be attached by one of the following methods: 11.1 By flanging and riveting in accordance with Part PR. 11.2 By flanging and butt welding in accordance with Part PG and Part PW. 10.3.1 In the portion of circumferential joints of horizontal-return tubular boilers exposed to the products of combustion, the shearing strength of the rivets shall be not less than 50% of the full strength of the plate corresponding to the thickness at the joint. 11.3 By attaching an outwardly or inwardly flanged tube sheet to the shell by fillet welding provided the following requirements are met: 10.3.2 When shell plates exceed 5/8 in. in thickness in horizontal-return tubular boilers, the portion of the plates forming the laps of the circumferential joints, where exposed to the fire or products of combustion, shall be planed or milled down as shown in Figure PFT-10 to a thickness of not over 9/16 in., provided the requirements in PR-17 are complied with. The entire circumference may be so planed or milled. The radius of the fillet at the edge of the planing shall be not less than 1 in. 11.3.2 The joint attaching an outwardly flanged tube sheet is wholly within the shell and forms no part thereof; 10.3.3 Where the circumferential joints of firetube boilers are to be seal welded, the thickness of the plates at the calking edges of such seams shall be at least 1/8 in. more than 60% of that required for a seamless shell of the same diameter, the same working pressure, and the same grade of 11.3.6 The construction conforms in all other respects to the requirements of this Section, including welding and postweld heat treating, except that radiographic examination is not required; 11.3.1 The tube sheet is supported by tubes, or stays, or both; 11.3.3 Inwardly flanged tube sheets are full fillet welded inside and outside; 11.3.4 The throat dimension of the full fillet weld is equal to, not less than 0.7 of the thickness of the head; 11.3.5 The shell at the welds is not in contact with primary furnace gases; 12 12 309 Primary Furnace gases are those in a zone where the design temperature of those gases exceeds 850°F. NATIONAL BOARD INSPECTION CODE 11.3.7 This construction shall not be used on the rear head of a horizontal-return tubular boiler and inwardly flanged tube sheets shall not be used on a boiler with an extended shell; 11.4.6 The construction conforms in all other aspects to the requirements of this Section including welding, and postweld heat treatment, except that radiographic examination is not required; 11.3.8 On inwardly flanged tube sheets, the length of flange shall conform to the requirements of PW-13 and the distance of the outside fillet weld to the point of tangency of the knuckle radius shall be not less than 1/4 in. 11.4.7 This construction shall not be used on the rear head of a horizontal-return tubular boiler. 11.4 By attaching an unflanged tube sheet to the shell by welding provided the following requirements are met: PFT-12 12.1 Allowable Working Pressure 12.1.1 The maximum allowable working pressure of tubes or flues of firetube boilers shall be as given in Table PFT-12.1. 11.4.1 The tube sheet is supported by tubes, or stays or both; 12.1.2 The maximum allowable working pressure for copper tubes or nipples subjected to internal or external pressure shall be as given in Table PFT-12.2. 11.4.2 The welded joint is wholly within the shell or wrapper sheet and forms no part thereof; 11.4.3 The weld is a full penetration weld equal at least to the full thickness of the tube sheet and applied from either or both sides; 11.4.4 The shell or wrapper sheet, where exposed to primary furnace gases6 and not water cooled does not extend more than 1/8 in. beyond the outside face of the tube sheet; TUBES The maximum allowable working pressure for copper-clad tubes subjected to external pressure shall be determined by the formula in Table PFT 12.1, in which t may be increased by one-half the thickness of the cladding. 12.2 Attachment of Tubes 11.4.5 The weld attaching a furnace or a lower tube sheet of a vertical firetube boiler to the furnace sheet is wholly within the furnace sheet and is ground flush with the upper or waterside of the tube sheet; FIGURE PFT-10 — Circumferential Joint For Thick Plates Of Horizontal-Return Tubular Boilers 9” 16 9” 16 Not less than 1” Not less than 1” 310 12.2.1 A firetube boiler shall have the ends of the tubes firmly rolled and beaded, or rolled and welded around the edge of the tube (see Figure PFT-12.1). Tube ends attached by rolling and welding are subject to the following provisions: 12.2.1.1 The tube sheet hole may be beveled or recessed to a depth at least equal to the thickness of the tubes. Where the hole is beveled or recessed, the projection of the tube beyond the tube sheet shall not exceed a distance equal to the tube thickness. The depth APPENDIX C — HISTORICAL BOILERS of any bevel or recess shall not be less than the tube thickness or 1/8 in. whichever is greater, nor more than one-third of the tube sheet thickness [see Figure PFT-12.1(f) and (g)]. the shell of the boiler, shall be determined by the following formula: P = 27,000 WD where, P = maximum allowable working pressure, pounds per square inch D = least horizontal distance between tube centers on a horizontal row, inches d = inside diameter of tubes, inches t = thickness of tube plate, inches W = distance from the tube sheet to opposite combustion chamber sheet, inches 12.2.1.2 Where no bevel or recess is employed, the tube shall extend beyond the tube sheet not less than a distance equal to the tube thickness, nor more than twice the tube thickness [see Figure PFT-12.1 (e)]. 12.2.1.3 On all types of welded attachments, the tubes shall be rolled before welding and again rolled lightly after the welding procedure. 12.2.2 Expanding of tubes by the Prosser method in lieu of rolling may be employed in combination with any beaded or welded attachment method. 12.2.3 Seal welding is permissible on any type of beaded attachment. Where seal welding is employed, a single hydrostatic test of the boiler after seal welding shall suffice. 12.2.4 The inner surface of the tube hole in any form of attachment may be grooved or chamfered. 12.2.5 The sharp edges of tube holes shall be taken off on both sides of the plate with a file or other tool. COMBUSTION CHAMBER AND FURNACES PFT-13 COMBUSTION CHAMBER TUBE SHEET 13.1 The maximum allowable working pressure on a tube sheet of a combustion chamber, where the crown sheet is not suspended from t(D - d) Where tubes are staggered the vertical distance between the centerlines of tube in adjacent rows must be not less than �� Example: Required the minimum allowable working pressure of a tube sheet supporting a crown sheet stayed by crown bars. Horizontal distance between centers, 4-1/8 in.; inside diameter of tubes, 2.782 in.; thickness of tube sheets 11/16 in; distance from tube sheet to opposite combustion-chamber sheet, 34-1/4 in.; measured from outside of tube plate to outside of back plate; material, steel. Substitution and solving: �� 13.2 Sling stays may be used in place of girders in all cases covered in PFT-13.1, provided, however, that when such sling stays are used, girders or screw stays of the same section area shall be used for securing the bottom of the combustion chamber to the boiler shell. 13.3 When girders are dispensed with and the top and bottom of combustion chambers are secured by sling stays, the sectional area of such stays shall conform to the requirements of rules for stayed surfaces. 311 NATIONAL BOARD INSPECTION CODE TABLE PFT-12.1 — Maximum Allowable Working Pressure For Steel Tubes Or Flues For Firetube Boilers For Different Diameters And Gages Of Tubes Conforming To The Requirements Of Specifications SA-178, SA-192, SA-209, SA-210, SA-226, OR SA-2501 Wall Thickness, in. Nearest Bwg No. 1 Size Outside Diameter, In. 1-1/2 1-3/4 2 2-1/4 2-1/2 3 3-1/4 3-1/2 4 4-1/2 5 5-3/8 5-1/2 6 0.095 0.105 0.120 13 12 11 420 560 770 280 380 520 240 320 440 210 280 390 190 250 350 170 230 310 ... 190 260 ... 180 240 ... 160 220 ... ... 200 ... ... 180 ... ... ... ... ... ... ... ... ... ... ... ... 0.135 0.150 0.165 10+ 9+ 8 980 ... ... 660 800 940 570 680 800 490 600 700 430 530 630 400 480 560 330 400 470 310 370 430 280 340 400 250 300 350 220 270 320 200 240 280 ... 230 270 ... 220 260 ... ... 240 0.180 0.200 0.220 0.240 7 65 4+ ... ... ... ... ... ... ... ... 920 1090 1240 1410 810 950 1090 1230 720 840 970 1090 650 760 870 990 540 630 730 820 500 590 670 760 460 540 620 700 410 480 550 620 360 420 490 550 330 380 440 490 300 360 410 460 300 350 400 450 270 320 370 410 These values have been increased to the next higher unit of 10 where the actual values exceed an even unit of 10. � �� where P = maximum allowable working pressure, pounds per square inch t = minimum wall thickness, inches D = outside diameter of tubes, inches 1 For pressures other than those given in the table, the allowable working pressures shall be the next higher unit of 10 above the values given by the formulas. For pressures below those given in the table, the gage thickness shall be not less than the minimum given in the table. TABLE PFT-12.2 — Maximum Allowable Working Pressure For Copper Tubes For Firetube Boilers Conforming To The Requirements Of Specification SB-752 (For use at Pressures Not to Exceed 250 psi or Temperatures Not to Exceed 406° F) Outside Diameter of Tube in. 12 11 10 9 8 7 6 5 4 2 3-1/4 4 5 170 ... ... ... 240 ... ... ... 250 110 ... ... 250 150 ... ... 250 220 130 ... 250 250 160 ... 250 250 250 150 250 250 250 190 250 250 250 230 2 Gage — Bwg These values have been rounded out to the next higher unit of 10. �� where � �� P = maximum allowable working pressure, pounds per square inch t = thickness of tube wall, inches D = outside diameter of tube, inches 312 APPENDIX C — HISTORICAL BOILERS PFT-14 not required. When the longitudinal and circumferential joints have been subjected completely to radiographic examination, the individual bend test for each furnace is not required. PLAIN CIRCULAR FURNACES 14.1 The shells of unstayed circular furnaces may be of any length or height and of any of the following constructions: 14.1.3 Riveted construction which meets the following requirements: 14.1.1 Seamless Construction 14.1.2 Double-welded butt-type construction subject only to the requirements that the welds are postweld heat treated in accordance with PW-39, and a bend test of a sample of the welding for each furnace meets the requirements of PW-53. Radiographic examination is 14.1.3.1 Circumferential and longitudinal joints shall have an efficiency not less than 50% nor less than PD/ 20,000t%, where, P = maximum allowable working pressure, pounds per square inch D = outside diameter, inches t = thickness of furnace walls, inches FIGURE PFT-12.1 — Acceptable Forms Of Tube Attachment On Firetube Boilers 14.1.3.2 Buttstrap seams shall be used only where they are protected from contact with the fire or flame. 14.2 The walls shall not be less than 5/16 in. in thickness. (a) 14.3 The furnace may be of any length or height. (b) 14.4 The following rules apply specifically to unstayed circular furnaces 12 in. in diameter and over: (d) (c) 14.4.1 Furnaces 12 to 18 in. in Outside Diameter, Inclusive. The maximum allowable working pressure for furnaces not more than 4-1/2 diameters in length or height shall be determined by formulas (1) and (2) as follows: Not less than t and in no case less than 1/8 in. Not over 2 t nor less than t but in no case more than 1/4 in. nor less than 1/8 in. Max t t (f) (e) Where the length does not exceed 120 times the thickness of the plate: t Not more than T/3 nor less than t or 1/8 in. whichever is the greater Max t and not more than T/3 or 1/8 in. whichever is the greater �� (1) T (g) t 313 NATIONAL BOARD INSPECTION CODE Where the length exceeds 120 times the thickness of the plate: a horizontal furnace shall be of butt- and single- or double-strap construction and shall be located below the grate. �� 14.4.8 The maximum allowable working pressure shall be determined by formulas (1) and (2); if over six diameters in length, L in the formula shall be taken as 6 times the diameter. (2) where, P = maximum allowable working pressure, pounds per square inch D = outside diameter of furnace, inches L = total length of furnace between centers of head rivet seams (not length of a section), inches T = thickness of furnace walls, sixteenths of an inch 14.4.9 Furnaces Over 38 in. in Diameter. Furnaces over 38 in. in diameter shall be fully stayed as flat surfaces in accordance with requirements of PFT-23.4. Where it is desired to apply staybolting to a furnace 38 in. or less in diameter, which is of proper thickness for the required working pressure under the above rules, the requirements of the Code for the stress allowed upon and the spacing of the staybolts may be disregarded. 14.4.2 The maximum allowable working pressure for furnaces over 4-1/2 diameters in length or height shall be determined in accordance with PFT-15. 14.4.3 Furnaces Over 18 in. in Outside Diameter to and Including 30 in. in Inside Diameter. The maximum allowable working pressure shall be determined by formulas (1) and (2); if over six diameters in length or height, L in the formula shall be taken as 6 times the diameter. 14.4.4 Furnaces Over 30 in. in Inside Diameter to and Including 36 in. in Inside Diameter. A riveted longitudinal joint may be of the lap type provided the furnace does not exceed 36 in. in length or height. 14.4.5 If the length of a horizontal furnace exceeds 36 in. and the joint is riveted, a butt- and single- or double-strap construction shall be used and shall be located below the grate. PFT-15 CIRCULAR FLUES The maximum allowable working pressure for seamless or welded flues over 5 in. in diameter, and including 18 in. in diameter shall be determined by one of the following formulas: 15.1 Where the thickness of the wall is not greater than 0.023 times the diameter: P= 10,000,000t3 D3 15.2 Where the thickness of the wall is greater than 0.023 times the diameter: 14.4.6 The maximum allowable working pressure shall be determined by formulas (1) and (2); if over six diameters in length, L in the formula shall be taken as 6 times the diameter. 14.4.7 Furnaces Over 36 in. in Inside Diameter to and Including 38 in. in Outside Diameter. When riveted the longitudinal joint of 314 P= 17,300t D - 275 where, P = maximum allowable working pressure, pounds per square inch D = outside diameter of flue, inches t = thickness of wall of flue, inches APPENDIX C — HISTORICAL BOILERS 15.3 The above formulas may be applied to riveted flues of the size specified provided the sections are not over 3 ft. in length and the efficiency of the joint is not less than: PD 20,000t Example: Given a flue 14 in. in diameter and 5/16 in. in thickness. The thickness of the wall is less than 0.023 times the diameter, hence the formula in (1) applies. Substituting the values in this formula: P= 10,000,000 x 5/16 x 5/16 x 5/16 PFT-16 14 x 14 x 14 16.4 An Adamson furnace may be assembled by welding, provided the outside edges of the flue flanges are attached to Adamson rings by full fillet welds; inside edges of the rings are welded to the flat portions of the flue flanges by full fillet welds; and the welds are postweld heat treated in accordance with PW-39. The maximum allowable working pressure shall be determined by the following formula: P= =110 psi When plain horizontal flues are made in sections not less than 18 in. in length and not less than 5/16 in. in thickness: Example: Given a furnace 44 in. in diameter, 48 in. in length, and 1/2 in. in thickness. Substituting values in formula: 16.1 They shall be flanged with a radius measured on the fireside of not less than 3 times the thickness of the plate, and the flat portion of the flange outside of the radius shall be at least 3 times the diameter of the rivet holes. 16.3 The depth of the Adamson ring between the flanges shall be not less than 3 times the diameter of the rivet holes, and the ring shall be substantially riveted to the flanges. The fire edge of the ring shall terminate at or about the point of tangency to the curve of the flange, and the thickness of the ring shall be not less than 1/2 in. D where, P = maximum allowable working pressure, pounds per square inch D = outside diameter of furnace, inches L = length of furnace section, inches t = thickness of plate, inches ADAMSON TYPE 16.2 The distance from the edge of the rivet holes to the edge of the flange shall be not less than the diameter of the rivet hole, and the diameter of the rivets before driving shall be at least 1/4 in. larger than the thickness of the plate. 57.6 (300t - 1.03L) P= 57.6 44 [(300 x 0.5) - (1.03 x 480] = 1.309 (150 - 49.44) = 131 psi The longitudinal and circumferential joints may be of the double-welded butt type, the only requirements being that the welds are postweld heat treated in accordance with PW-39 and a bend test of a sample of the welding for each furnace meets the requirements of PW-53, no radiographic examination being required. When the longitudinal and circumferential joints have been subjected completely to radiographic examination, the individual bend test for each furnace is not required. 315 NATIONAL BOARD INSPECTION CODE 17.2 The stiffening ring after fabrication has a thickness of not less than 5/16 in. and not more than 13/16 in. and in no case thicker than 1-1/4 times the furnace wall thickness. t = minimum required wall thickness of furnace or flue, inches L = design length of a furnace section, taken as the greatest center-to-center distance between any two adjacent stiffening rings, or the distance from the center of the first stiffening ring to the center of the furnace weld attachment, inches. In case a flared end assembly is used, the distance shall be measured to the point of tangency of the flare and the furnace and the adjacent stiffening ring. Do = outside diameter of furnace or flue, inches P = maximum allowable working pressure, pounds per square inch 17.3 The ratio of the height of the stiffening ring to its thickness (Hr /Tr ) is not greater than 8 nor less than 3. The required wall thickness of a ring reinforced furnace or flue shall not be less than that determined by the following procedure: 17.4 The stiffening ring is attached to the furnace by a full penetration weld on each side. Step 1: Assume value for t and L. Determine the ratios L/Do and Do/t; 17.5 The thickness of the furnace wall or flue is a minimum of 5/16 in. Step 2: Enter left-hand side of Figure PFT 17.1 at the value of L/Do determined in Step 1; PFT-17 RING REINFORCED TYPE Horizontal cylindrical flues or furnaces (Figure PFT-17.2) may be constructed with completely circular stiffening rings provided the following requirements are met: 17.1 The stiffening ring is rectangular in cross section and is fabricated from one piece of plate, or from plate sections or bars provided full penetration welds are used in assembling. 17.6 The spacing, L, of the rings on the furnace is not greater than 60t or 36 in., whichever is smaller. Step 3: Move horizontally to the line representing the value of Do/t determined in Step 1;7 17.7 The design temperature of the furnace is taken as 100° F higher than the water temperature. Step 4: From this intersection move vertically to the material line of the proper temperature; 13 17.8 The boiler design permits replacement of the furnace. A flared or welded OG ring is an acceptable type of assembly. Step 5: From this intersection move horizontally to the right and read the value of B; 17.9 The completed furnace assembly is postweld heat treated but radiographic examination is not required. 17.10 The thickness of the furnace wall and design of stiffening rings are determined by the use of Figure PFT-17.1. The symbols defined below, and shown in Figures PFT-17.1 and PFT-17.2 are used in the formulas of this paragraph: 316 Step 6: Compute the allowable working pressure, Pa , by the following formula: �� 13 � �� For immediate temperatures and Do/t ratios, interpolations may be made between the lines on the chart in Figure PFT-17.1. APPENDIX C — HISTORICAL BOILERS Do /t=10 Do /t=15 Do /t=20 Do /t=25 Do /t=30 Do /t=40 Do /t=50 Do /t=60 Do /t=80 Do /t=100 Do /t=125 Do /t=150 50,000 40,000 35,000 30,000 25 25,000 20 18 16 14 20,000 UP TO 300o F 18,000 o UP TO 500 F 16,000 UP TO 700o F 14,000 UP TO 800o F 12,000 UP TO 900o F 10,000 9,000 8,000 7,000 6,000 5,000 4,000 3,500 3,000 2,500 2.0 1.8 1.6 1.4 2,000 1,800 1,600 1,400 1.2 1,200 1.0 0.90 0.80 0.70 1,000 900 800 700 Do 2.5 10 /t= Do 15 /t= 0.60 0.50 600 500 Do /t= 40 20 =25 =30 50 t=60 /t= o /t= / /t /t Do Do D Do Do 0.40 0.35 0.30 0.25 0.20 0.18 0.16 0.14 0.12 Do 0.05 0.00001 2 3 4 5 6 78 0.0001 2 3 4 5 6 78 0.001 FACTOR A 317 2 3 4 5 678 0.01 80 /t= 0 Do 10 /t= Do 5 12 /t= 0 15 /t= Do 3 4 5 678 0.1 0 20 /t= Do 50 t=2 Do / 00 t=3 Do / 00 t=4 Do / 00 t=5 Do / 600 t= Do / 2 00 t=8 0 00 0.06 Do / t=1 Do / 0.10 0.09 0.08 0.07 400 350 300 250 200 180 160 140 120 100 90 80 70 60 50 FACTOR B = P(D0 /t) 4.0 3.5 3.0 00 00 500 600 10 00 t= t= t=8 Do /t= Do / Do / Do / 5.0 t=4 10 9.0 8.0 7.0 6.0 Do / 30 12 Length /Outside Diameter = L/D0 Do /t=200 40 35 Do /t=250 50 Do /t=300 FIGURE PFT-17.1 — Chart for Determining Wall Thickness of Ring Reinforced Furnaces When Constructed of Carbon Steel (Specified yield Strength 30,000 to 38,000 psi) NATIONAL BOARD INSPECTION CODE Step 7: Compare Pa with P. If Pa is less than P, select greater value of t or a smaller value of L or some combination of both to increase Pa , so that it is equal to or greater than P. (An example shown in Appendix A-200.) Step 1: Assuming that the furnace has been designed and Do , L and t are known, select a rectangular member to be used for a stiffening ring and determine its area, As , and its moment of inertia, I. Then calculate B by the formula: The required moment of inertia of a circumferential stiffening ring shall not be less than that determined by the formula: �� where B = factor on the right-hand side of Figure PFT-17.1 and P, Do , t, As , and L are as defined above; where, Is = required moment of inertia of the stiffening ring about its neutral axis parallel to the axis of the furnace, inches As = cross-sectional area of the stiffening ring, square inches A = factor determined from Figure PFT 17.1 Step 2: Enter the right-hand side of Figure PFT-17.1 at the value of B determined in Step 1; Step 3: Follow horizontally to the material line for the correct temperature; 14 Step 4: Move down vertically to the bottom of the chart and read the value of A; P, Do , L, and t are as defined above Step 5: Compute the value of the required moment of inertia, Is , from the formula given above; The moment of inertia for a stiffening ring shall be determined by the following procedure: FIGURE PFT 17.2 — Acceptable Type Of Ring Reinforced Furnace Tr Hr Alternate End Assemblies Full Penetration Continuous Weld Both Sides of Rings t L L �� Step 6: If the required Is is greater than the moment of inertia, I for this section selected in Step 1, select a new section with a larger moment of inertia and determine a new value of Is . If the required Is is smaller than I for the section selected in Step 1, that section should be satisfactory. (An example is shown in Appendix A-200.) Tr Hr L The longitudinal and circumferential joints may be of the double-welded butt type, the only requirements being Do For immediate temperatures and Do/t ratios, interpolations may be made between the lines on the chart in Figure PFT-17.1. 14 318 APPENDIX C — HISTORICAL BOILERS that the welds are postweld heat treated in accordance with PW-39 and a bend test of a sample of the welding for each furnace meets the requirements of PW-53, no radiographic examination being required. When the longitudinal and circumferential joints have been subjected completely to radiographic examination, the individual bend test for each furnace is not required. the actual length of the plain furnace section exceeds 120 times the plate thickness, Equation (2) shall be used. A plain furnace section whose length is such that twice the actual length exceeds 4-1/2 diameters shall have its maximum allowable working pressure determined in accordance with PFT-15. Combination-type furnaces for external pressure may be constructed by combining a plain circular section and a corrugated section provided: 18.2.2 Furnaces over 18 in. to and including 38 in. in outside diameter. The maximum allowable working pressure of a plain furnace section shall be determined by Equation (1) and (2) in PFT-14.4. When twice the actual length of the plain furnace section exceeds 6 times the furnace diameter, L in the formulas shall be taken as 6 times the diameter. 18.1 Each type of furnace is designed to be self-supporting, requiring no support from the other furnace at their point of connection. 18.3 The maximum allowable working pressure of the corrugated section shall be determined from PFT-19. 18.2 Paragraphs PFT-14 and PFT-15 are used for calculating the maximum allowable working pressure of the plain section. In applying the length in the text or L in the formulas, the value used shall always be twice the actual length of the plain section. The actual length of the plain section is the distance measured from the centerline of the head attachment weld to the centerline of the full penetration weld joining the two sections. 18.4 The full penetration weld joining a plain self-supporting section to a corrugated selfsupporting section, shall be located as shown in Figure PFT-18. PFT-18 COMBINED PLAIN CIRCULAR AND CORRUGATED TYPE 18.2.1 Furnaces 12 in. to 18 in. in outside diameter inclusive. A plain furnace section whose length is such that twice the actual length does not exceed 4-1/2 diameters shall have its maximum allowable working pressure calculated by Equation (1) or (2) in PFT-14.4. If twice the actual length of the plain furnace section does not exceed 120 times the thickness of the plate, Equation (1) shall be used. If twice 18.5 The longitudinal and circumferential joints may be fusion welded of the doublewelded butt type, the only requirements being that the welds are postweld heat treated in accordance with PW-39 and a bend test of a sample of the welding for each furnace meets the requirements of PW-53, no radiographic examination being required. When the longitudinal and circumferential joints have been subjected completely to radiographic examination, the individual bend test for each furnace is not required. 319 NATIONAL BOARD INSPECTION CODE C = 14,000, a constant for Purves furnaces, when rib projections are not more than 9 in. from center to center and not less than 1-5/8 in. deep. C = 14,000 a constant for Brown furnaces, when corrugations are not more than 9 in. from center to center and not less than 1-5/8 in. deep. C = 10,000, a constant for furnaces corrugated by sections not more than 18 in. from center to center and not less than 1-1/2 in. deep, measured from the least inside to the greatest outside diameter of the corrugations, and having the ends fitted one into the other and substantially riveted together, provided that the plain parts at the ends do not exceed 12 in. in length. FIGURE PFT-18 — Connection Between Plain And Corrugated Furnace 3 Max 3 t c or 1-1/2" (whichever is less) 1 tc Point of Tangency PFT-19 CORRUGATED FURNACES 19.1 The maximum allowable working pressure on corrugated furnaces, such as the Leeds suspension bulb, Morison, Fox, Purves, or Brown, having plain portions at the ends not exceeding 9 in. in length (except flues especially provided for), when new and practically circular, shall be computed as follows: P= Ct D where, P = maximum allowable working pressure, pounds per square inch t = thickness, inches, not less than 5/16 in. for Leeds, Morison, Fox, and Brown, and not less than 7/16 in. for Purves and other furnaces corrugated by section not over 18 in. long D = mean diameter, inches C = 17,300, a constant for Leeds furnaces, when corrugations are not more than 8 in. from center to center and not less than 2-1/4 in. deep. C = 15,600, a constant for Morison furnaces, when corrugations are not more than 8 in. from center to center and the radius of the outer corrugation is not more than one-half of the suspension curve. C = 14,000, a constant for Fox furnaces, when corrugations are not more than 8 in. from center to center and not less than 1-1/2 in. deep. In calculating the mean diameter of the Morison furnace, the least inside diameter plus 2 in. may be taken as the mean diameter. The longitudinal and circumferential joints may be fusion welded of the double-welded butt type, the only requirements being that the welds are postweld heat treated in accordance with PW-39 and a bend test of a sample of the welding for each furnace meets the requirements of PW-53, no radiographic examination being required. When the longitudinal and circumferential joints have been subjected completely to radiographic examination, the individual bend test for each furnace is not required. 19.2 The thickness of a corrugated or ribbed furnace shall be ascertained by actual measurement by the furnace manufacturer, by gaging the thickness of the corrugated portions. If a hole is used, the diameter of a hole drilled through the sheet to determine its thickness shall be 3/8 in. When the furnace is installed the hole shall be located beneath the bottom of the grate and closed by a plug. For the Brown and Purves furnaces, the holes shall be in the center of the second flat; for 320 APPENDIX C — HISTORICAL BOILERS the Morison, Fox and other similar types, in the center of the top corrugation, at least as far in as the fourth corrugation from the end of the furnace. PFT-20 ATTACHMENT OF FURNACES 20.1 Riveted Construction. Furnaces may be attached to an inwardly or outwardly flanged head or tube sheet by riveting in accordance with the rules of Part PR and applicable rules in Part PFT. 20.3 Full Penetration Weld Construction. A furnace may be attached by a full penetration weld, with the furnace extending at least through the full thickness of the tube sheet but not beyond the toe of the weld, and the toe shall not project beyond the face of the tube sheet by more than 3/8 in. unless protected from overheating by refractory material or other means. 20.4 Throat Sheets. Throat sheets and inside and outside front furnace sheets when fully stayed may be attached as required in PFT11.4. 20.2 Fillet Welded Construction. In a scotch-type boiler, a furnace may be attached to an outwardly flanged opening in a front tube sheet by a circumferential fillet weld, or a furnace may be attached to either tube sheet by flaring the end which extends beyond the outside face of the head to an angle of 20 to 30 deg. and using a circumferential fillet weld, provided the following requirements are met: 20.5 Furnace Sheets. Attached by Welding Vertical firetube boilers may be constructed by welding the ogee bottom of the furnace sheet to the outside shell as shown in Figure PFT-20 provided the following requirements are met: 20.2.1 The area of the head around the furnace is stayed by tubes, stays, or both in accordance with the requirements of this Section. 20.5.2 The joint is wholly within the shell and forms no part thereof. 20.5.1 The tube or crown sheet is fully supported by tubes, or stays or both. 20.5.3 The weld is not in contact with primary furnace gases.9 20.2.2 The joint is wholly outside the furnace. 20.5.4 The throat dimension of the full fillet weld is not less than 0.7 times the thickness of the furnace sheet. 20.2.3 The throat dimension of the full fillet weld is not less than 0.7 times the thickness of the head. 20.5.5 The maximum depth of the waterleg does not exceed 4 in., and the radius 20.2.4 Unless protected by refractory material, the furnace does not extend beyond the outside face of the tube sheet, a distance greater than the thickness of the tube sheet. Any excess shall be removed before welding. 20.2.5 The construction conforms in all other respects to the requirements of this Section including welding and postweld heat treating, except that radiographic examination is not required. FIGURE PFT-20 — Welding Ogee Ring 1 2 Pitch d (max) (max) 9 321 d (max = 4") Primary Furnace gases are those in a zone where the design temperature of those gases exceeds 850°F NATIONAL BOARD INSPECTION CODE of the ogee is not greater than the inside width of the waterleg. in Figure PG-31(g) in compliance with the requirements of Par. PG-31 provided: 20.5.6 The pitch of the lower row of staybolts meets the requirements of PFT-26.6. 21.3.1 The width of the waterleg does not exceed 4 in. 20.5.7 The construction conforms in all other respects to Code requirements including welding and postweld heat treating, except that radiographic examination is not required. 21.3.2 The thickness of the mud ring plate is at least 1/2 in. PFT-21 FIREBOXES AND WATERLEGS 21.1 Fireboxes and waterlegs may be of riveted construction provided the rules in Part PR and all applicable rules in Part PFT are followed. 21.2 Welded construction may be used in lieu of riveted joints in the fireboxes of internally fired boilers provided the welds are between two rows of staybolts, or in the case of flat surfaces the weld is not less than one-half of a staybolt pitch from the corner. In vertical tubular and firebox types of boilers the bottom edges of the plates may be attached by fusion welding, provided the load due to internal pressure is carried by staybolting and the inside width of the waterleg does not exceed 4 in. An acceptable construction is as shown in Figure PWT-12.2 with both plates flanged. As an alternative construction one plate only need be flanged, provided the weld joining the flanged plate to the straight plate is a groove weld having penetration for its full depth and the weld is outside of the header. The plates may be considered to be fully supported if stayed in accordance with the requirements of PFT 26.8. The welds shall be postweld heat treated but radiographic examination is not required. Any crevices between the mud ring and the sheets of the furnace section of a locomotive-type boiler may be made tight with seal welding when the mud ring is secured by rivets. The abutting ends of mud rings may be welded. STAYED SURFACES PFT-22 GENERAL The rules of Part PG pertaining to stayed surfaces which are applicable to firetube boilers shall be used in conjunction with the following requirements. PFT-23 WORKING PRESSURE FOR CURVED SURFACES 23.1 The maximum allowable working pressure for curved stayed surfaces subject to internal pressure shall be obtained by the following two methods, and the minimum value obtained shall be used: The welds shall be postweld heat treated but radiographic examination is not required. 21.3 Mud rings of plate material permissible under this Section of the Code may be used in the construction of waterlegs of vertical firetube boilers and may be attached as shown 322 23.1.1 The maximum allowable working pressure shall be computed without allowing for the holding power of the stays, due allowance being made for the weakening effect of the holes for the stays or riveted longitudinal joint or other construction. To this pressure there shall be added the pressure obtained by the formula for stayed surfaces given in PG-46 using 1.3 for the value of C. APPENDIX C — HISTORICAL BOILERS 23.1.2 The maximum allowable working pressure shall be computed without allowing for the holding power of the stays, due allowance being made for the weakening effect of the holes for the stays or riveted longitudinal joint or other construction. To this pressure there shall be added the pressure corresponding to the strength of the stays for the allowable stress values in Table PG-23.1, each stay being assumed to resist the pressure acting on the full area of the external surface supported by the stay. from the wrapper sheet to the top of the crown sheet at the center bears to the distance measured on a radial line through the other section, from the wrapper sheet to a line tangent to the crown sheet and at right angles to the radial lines (see Figure PFT-23.1). 23.2 The maximum allowable working pressure for a stayed wrapper sheet of a locomotive-type boiler shall be determined by the two methods given above and by the following formula and the smallest of the three values obtained shall be used: The longitudinal pitch between the staybolts, or between the nearest row of staybolts and the row of rivets at the joints between the furnace sheet and the tube sheet or the furnace sheet and mud ring, shall not exceed that given by the following formula: �� where, P = maximum allowable working pressure, pounds per square inch t = thickness of wrapper sheet, inches E = minimum efficiency of wrapper sheet through joints or stay holes R = radius of wrapper sheet, inches ∑(s x sin a) = summated value of transverse spacing s x sin a for all crown stays considered in one transverse plane and on one side of the vertical axis of the boiler s = transverse spacing of crown stays in the crown sheet, inches a = angle any crown stay makes with the vertical axis of boiler 11,000 = allowable stress, pounds per square inch 23.3 A furnace for a vertical firetube boiler 38 in. or less in outside diameter which requires staying shall have the furnace sheet supported by one or more rows of staybolts, the circumferential pitch not to exceed 1.05 times that given by the formula in PG-46. � where, L = longitudinal pitch of staybolts P = maximum allowable working pressure, pounds per square inch t = thickness of furnace sheet, inches R = outside radius of furnace, inches When values by this formula are less than the circumferential pitch, the longitudinal pitch may be as large as the allowable circumferential pitch. The above formula applies to the longitudinal center section of the wrapper sheet, and in cases where E is reduced at another section, the maximum allowable working pressure based on the strength at that section may be increased in the proportion that the distance 323 FIGURE PFT-23.1 — Stayed Wrapper Sheet of Locomotive-Type Boiler o 90 NATIONAL BOARD INSPECTION CODE The stress in the staybolts shall not exceed 7500 psi. and shall be determined as specified in PFT-23.4. FIGURE PFT-23.2 — Proper Location of Staybolts Adjacent to Longitudinal Joint in Furnance Sheet 23.4 In furnaces over 38 in. in outside diameter and combustion chambers not covered by special rules in this Section which have curved sheets subject to pressure on the convex side, neither the circumferential nor longitudinal pitches of the staybolts shall exceed 1.05 times that given by the rules in PG-46. The stress in staybolts shall not exceed 7500 psi based on the total load obtained by multiplying the product of the circumferential and longitudinal pitches less the minimum cross-sectional area, by the maximum allowable working pressure. 23.5 Furnaces of Vertical Boilers. In a vertical firetube boiler, the furnace length, for the purpose of calculating its strength and spacing staybolts over its surface, shall be measured from the center of rivets in the bottom of the waterleg to the center of rivets in the flange of the lower tubesheet. 23.6 When the longitudinal joint of the furnace sheet of a vertical firetube boiler is of lap-riveted construction and staybolted, a staybolt in each circular row shall be located near the longitudinal joint, as shown in Figure PFT-23.2. PFT-24 FLEXIBLE STAYBOLTS Flexible-type staybolts having a cover cap welded under the provisions of PW-15 to the outer sheet may be used in the construction of locomotive-type boilers provided the bolts are hollow-drilled from the threaded end into and partly through the ball head to allow for proper inspection, and so that any breakage is disclosed by leakage at the inner end. These welded joints need not be postweld heat treated nor radiographed. PFT-25 ATTACHMENT OF STAYS AND STAYBOLTS BY WELDING The attachment of stays and staybolts by welding shall meet the requirements of PW-19. PFT-26 MAXIMUM SPACING 26.1 The maximum distance between centers of rivets, or between the edges of tube holes and the centers of rivets attaching the crowfeet of stays to the stayed surface, shall be p as determined in PG-46 using 2.5 for the value of C. 26.2 The maximum distance between the edges of tube holes and the centers of other types of stays shall be p as determined by the formula in PG-46, using the value of C given for the thickness of plate and type of stay used. 26.3 For a flanged head, riveted or welded to the shell, the maximum distance between the inner surface of the supporting flange and lines parallel to the surface of the shell passing through the center of the stay, or the rivets attaching crowfeet of stays shall be p as determined by the formula in PG-46, plus the inside radius of the supporting flanges using the following C factors: For riveted crowfoot stays—Use 2.1 for C factor. 324 APPENDIX C — HISTORICAL BOILERS For other types of stays—Use the C factor which applies to the thickness of the head plate and type of stay used [see Figure A-8(i) and (j)]. 26.4 For unflanged heads, the maximum distance between the inner surface of the shell and the centers of stays, or rivets attaching crowfeet of stays, shall not be more than one-half the maximum allowable pitch as determined by PG-46, using 2.5 for the value of C, plus 2 in. [see Figure A-8(k)]. 26.5 The pitch of diagonal stays attached by welding between the shells and tube sheets of horizontal tubular and scotch boilers, and for other stays when supported plate is not exposed to radiant heat, as determined by PG-46, may be greater than 8-1/2 in., but shall not exceed 15 times the stay diameter. 26.6 The pitch of the lower row of staybolts of a vertical firetube boiler, which is required to be stayed by the rules in this Section, and which is fabricated by welding the ogee bottom of the furnace sheet to the outside shell, shall not exceed one-half the maximum allowable pitch as determined by PG-46, measured from the center of the staybolt to the tangent of the ogee (see Figure PFT-20). 26.7 The spacing of staybolts around door holes fabricated by fusion welding of the full penetration type of two-flanged sheets, which are required to be stayed by the rules of this Section (see Figure PWT-12.2), shall not exceed one-half the maximum allowable pitch determined by PG-46, measured from the center of the staybolt to the points of tangency of the flanges. 26.8 If the furnace sheets are required to be stayed by the rules of this Section, the spacing of staybolts around door holes and the spacing of the first row of staybolts from the bottom of the mud ring fabricated by fusion welding of the full penetration type when either or both sheets are not flanged [see Figure A-8(l), (m) and (n)] shall not exceed one-half the maximum pitch determined by PG-46, plus 2 in., measured from the center of the staybolt to the root of the weld. 26.9 The maximum distance from the first row of stays to a full penetration weld in compression applied from either or both sides of the tube sheet, attaching the crown sheet of a furnace or combustion chamber to a stayed head or tube sheet shall not exceed the pitch determined by PG-46, measured from the center of the stay to the furnace or combustion chamber side of the head or tube sheet [see Figures A-8(o) and (p)]. 26.10 When a flanged-in manhole opening with a flange depth of not less than 3 times the required thickness of the head, or when an unflanged manhole ring meeting the requirements of PG-32 through PG-39 is provided in a flat stayed head of a firetube boiler, as shown in Figures A-8(q) and (r), the area to be stayed as required by PFT-31 may be reduced by 100 sq. in. provided both the following requirements are met: 26.10.1 The distance between the manhole opening and the inside of the shell does not exceed one-half the maximum allowable pitch for an unflanged manhole and one-half the maximum allowable pitch plus the radius of the head flange for a flanged-in manhole in a flanged head. 26.10.2 The distance between the centers of the first rows of stays, or the edges of tube holes, and the manhole opening does not exceed one-half the maximum allowable pitch as determined by PG-46. 26.11 In applying these rules and those in PG-46 to a head or plate having a manhole or reinforced opening, the spacing applies only to the plate around the opening and not across the opening. 26.12 For stays at the upper corners of fireboxes, the pitch from the staybolt next to the corner to the point of tangency to the corner curve shall be (see Figure PFT-26): 325 NATIONAL BOARD INSPECTION CODE would make it come 7 in., the distance of 6 in. shall be used in computing the load to be carried. FIGURE PFT-26 — Pitch of Staybolts Adjacent to Upper Corners of Fireboxs p β t PFT-28 28.1 The required area at the point of least net cross section of staybolts and stays shall be as given in PG-49. The maximum allowable stress per square inch at point of least net cross-sectional area of staybolts and stays shall be given as in Table PG-23.11. In determining the net cross-sectional area of drilled or hollow staybolts, the cross-sectional area of the hole shall be deducted. p r MAX r = p AS CALULATED BY PAR. PFT-26.2 MIN r = 3 t �� where T = thickness of plate in sixteenths of an inch P = maximum allowable working pressure, pounds per square inch C = factor for the thickness of plate and type of stay used as required in Part PG-46. PFT-27 STAYBOLTS AND STAYS AREA SUPPORTED BY STAY 27.1 The full pitch dimensions of the stays shall be employed in determining the area to be supported by a stay, and the area occupied by the stay shall be deducted therefrom to obtain the net area. The product of the net area in square inches by the maximum allowable working pressure in pounds per square inch gives the load to be supported by the stay. 27.2 Where stays come near the outer edge of the surfaces to be stayed and special allowances are made for the spacing, the load to be carried by such stays shall be determined by neglecting the added area provided for these special allowances. Example: If the maximum pitch by PG-46 would make a staybolt come 6 in. from the edge of the plate and a special allowance 28.2 The length of the stay between supports shall be measured from the inner faces of the stayed plates. The stresses are based on tension only. For computing stresses in diagonal stays, see PFT-32. 28.3 When stay rods are screwed through sheets and riveted over, they shall be supported at intervals of not to exceed 6 ft. Stay rods over 6 ft. in length may be used without support if fitted with nuts and washers or attached by welding under PW-19, provided the least cross-sectional area of the stay rod is not less than that of a circle 1 in. in diameter. PFT-29 STRUCTURAL REINFORCEMENTS 29.1 When channels or other structural shapes are riveted to the boiler heads for attaching through stays, the transverse stress on such members shall not exceed 12,500 psi. In computing the stress, the section modulus of the member shall be used without addition for the strength of the plate. The spacing of the rivets over the supported surface shall be determined by the formula in PG-46, using 2.5 for the value of C. 29.2 Provided the outstanding legs of the two members are fastened together so that they 326 APPENDIX C — HISTORICAL BOILERS act as one member in resisting the bending action produced by the load on the rivets attaching the members to the head of the boiler, and provided that the spacing of these rivets attaching the members to the head is approximately uniform, the members may be computed as a single beam uniformly loaded and supported at the points where the through stays are attached. PFT-30 from the shell as shown in Figures PFT-31.1 and PFT-31.2. The value of d used may be the larger of the following values: d = the outer radius of the flange, not exceeding 8 times the thickness of the head d = 80t/√P where d = unstayed distance from shell, inches t = thickness of head in inches P = maximum allowable working pressure, pounds per square inch STAYING SEGMENTS OF HEADS 30.1 A segment of a head shall be stayed by head-to-head, through, diagonal, crowfoot, or gusset stays, except that a horizontal-return tubular boiler may be stayed as provided in PFT-35. 30.2 Stays shall be used in the tube sheets of a firetube boiler if the distance between the edges of the tube holes exceeds the maximum pitch of staybolts for the corresponding plate thickness and pressure given in PG-46. 31.2 The area of a segment of an unflanged head to be stayed shall be the area enclosed by the shell and a line drawn 2 in. from the tubes. 31.3 The rules on PFT-30.2 shall be used to determine if staying is required. Any part of the tube sheet which comes between the tube or cylindrical furnace and the shell need not be stayed if the greatest distance measured along a radial line from the inner surface of the shell to the center point of tangent to any two tube holes or tube hole and cylindrical furnace on the shell side of such holes does not exceed 1.5 times the value of p obtained by applying the formula of PG-46 with C equal to 2.1 or 2.2 depending upon the plate thickness. The tube holes, or tube hole and cylindrical furnace (see Figure PFT-30), to which a common tangent may be drawn in applying this rule, shall not be a greater distance from edge to edge than the maximum pitch referred to. PFT-31 AREAS OF HEADS TO BE STAYED 31.3.1 The net area to be stayed in a segment of a flanged head may be determined by the following formula: �� 327 � � � �� where, A = area to be stayed, square inches H = distance from tubes to shell, inches d = distance determined by formula in PFT-31.1 for flanged heads d = zero for unflanged heads R = radius of boiler head, inches 31.3.2 The net area to be stayed in a segment of an unflanged head may be determined by the following formula: �� 31.1 The area of a segment of a flanged head to be stayed shall be the area enclosed by lines drawn 2 in. from the tubes and a distance d � � � �� where, A = area to be stayed, square inches NATIONAL BOARD INSPECTION CODE FIGURE PFT-30 — Example of Staying of Heads Adjacent to Cylindrical Furnaces 1 12 p 1 12 p 1 12 p 1 12 p 1 12 p FIGURE PFT-31.1 — Method of Determining Net Area of Segment of a Head FIGURE PFT-31.2 — Method of Determining Net Area of Irregular Segment of a Head FIGURE PFT-32 — Measurements for Determining Stresses in Diagonal Stays 328 APPENDIX C — HISTORICAL BOILERS 31.4 When stays are required, the portion of the heads below the tubes in a horizontalreturn tubular boiler shall be supported by through stays attached by welding under PW19 or with nuts inside and outside at the front head and by attachments which distribute the stress at the rear head. 32.2 For staying segments of tube sheets such as in horizontal-return tubular boilers, where L is not more than 1.15 times l for any stay, the stays may be calculated as direct stays allowing 90 percent of the allowable stress value given in Table PG-23.1. The distance in the clear between the bodies of the stays or of the inside stays where more than two are used shall not be less than 10 in. at any point. PFT-33 When horizontal firetube boilers are set so that the products of combustion do not come in contact with the lower part of the shell, tubes may be used instead of through stays at the sides of the manhole opening, if used. PFT-32 STRESSES IN DIAGONAL AND GUSSET STAYS 32.1 To determine the required area of a diagonal stay, multiply the area of a direct stay required to support the surface by the slant or diagonal length of the stay; and divide this product by the length of a line drawn at right angles to surface supported to center of palm of diagonal stay as follows: �� where, A = sectional area of diagonal stay, square inches a = sectional area of direct stay, square inches L = length of diagonal stay as indicated in Figure PFT-32, inches l = length of line drawn at right angles to boiler head or surface supported to center of palm of diagonal stay, as indicated in Figure PFT-32 Example: Given diameter of direct stay=1 in. a=0.7854 sq. in., L=60 in., l=48 in.; substituting and solving: Diameter=1.11 in. = 1-1/8 in. DESIGN OF STAYS AND STAY CONNECTIONS All rivet holes and pinholes shall conform to the requirements of PR-32 and the pins shall be made a neat fit. To determine the sizes that shall be used, proceed as follows: 33.1 Determine the required cross-sectional area of the stay in accordance with PFT-29. 33.2 Design the body of the stay so that the cross-sectional area shall be at least equal to the required cross-sectional area of the stay for unwelded stays. Where the stays are forge welded, the cross-sectional area at the weld shall be at least as great as that computed for a stress of 6,000 psi (see Table PG-23.3). 33.3 Make the area of pins to resist double shear at least three-quarters of the required cross-sectional area of the stay. 33.4 Make the combined cross section of the eye at the side of the pin (in crowfoot stays) at least 25 percent greater than the required cross-sectional area of the stay. 33.5 Make the cross-sectional areas through the blades of diagonal stays where attached to the shell of the boiler at least equal to the required rivet section, that is, at least equal to 1-1/4 times the required cross-sectional area of the stay. 33.6 Design each branch of a crowfoot to carry two-thirds the total load on the stay. 33.7 Make the net sectional areas through the sides of the crowfoot, tee irons, or similar fastenings at the rivet holes at least equal to the required rivet section, that is, at least equal 329 NATIONAL BOARD INSPECTION CODE to 1-1/4 times the required cross-sectional area of the stay. FIGURE PFT-35 — Staying of Head with Steel Angles in Tubular Boiler 33.8 Make the combined cross-sectional area of the rivets at each end of the stay at least 1-1/4 times the required cross-sectional area of the stay. 3" β See Table Not over 8" Not less than 2" Not over 4" PFT-34 Α See Table Not over 3" GUSSET STAYS Gusset stays when constructed of triangular right-angled web plates secured to single- or double-angle bars along the two sides at right angles shall have a cross-sectional area (in a plane at right angles to the longest side and passing through the intersection of the two shorter sides) not less than 10 percent greater than would be required for a diagonal stay to support the same surface, calculated by the formula of PFT-32, assuming the diagonal stay is at the same angle as the longest side of the gusset plate. PFT-35 STAYING OF UPPER SEGMENTS OF TUBE HEADS BY STEEL STRUCTURAL SHAPES 35.1 When the shell of a boiler does not exceed 36 in. in diameter and is designed for a maximum allowable working pressure TABLE PFT-35 Sizes of Angles Required for Staying Segments of Head (With the short legs of the angles attached to the head of the boiler.) Height of Segment Dimension β in Fig. PFT-35 10 11 12 13 14 15 16 Thickness, In. 30-in. Boiler Angle 3 by 2-1/2 in. Angle 3-1/2 by 3 in. Angle 4 by 3 in. 3/8 5/16 5/16 7/16 3/8 5/16 9/16 7/16 3/8 ... 9/16 7/16 ... ... 1/2 ... ... ... ... ... ... 34-in. Boiler Angle 3-1/2 by 3 in. Angle 4 by 3 in. Angle 5 by 3 in. ... ... ... 7/16 5/16 5/16 1/2 7/16 5/16 11/16 1/2 5/16 ... 5/8 3/8 ... ... 1/2 ... ... ... 36-in. Boiler Angle 4 by 3 in. Angle 5 by 3 in. Angle 6 by 3 in. ... ... ... ... ... ... 7/16 5/16 ... 9/16 3/8 ... 5/8 7/16 3/8 3/4 1/2 3/8 ... 5/8 7/16 Dimension A in. Fig. PFT-35 6-1/2 7 7-1/2 8 8-1/2 9 9-1/2 330 APPENDIX C — HISTORICAL BOILERS not exceeding 100 psi, the segment of heads above the tubes may be stayed by steel structural shapes as specified in Table PFT-35 and Figure PFT-35, except that structural shapes of equal thickness and greater depth of outstanding leg, or of greater thickness and the same or greater depth of outstanding leg, may be substituted for those specified. The legs attached to heads may vary in depth 1/2 in. above or below the dimensions specified in Table PFT-35. PFT-36 36.1 Crown bars and girder stays for tops of combustion chambers and back connections or wherever used, shall be proportional to conform to the following formula: �� 35.4 The distance from the center of the structural shapes to the shell of the boiler, marked A in Figure PFT-35, shall not exceed the values in Table PFT-35, but in no case shall the leg attached to the head of the lower angle come closer than 2 in. from the top of the tubes. 35.5 When segments are beyond the range specification in Table PFT-35, the heads shall be stayed in accordance with the requirements in these rules. �� where, W = extreme distance between supports of, in a scotch marine boiler, the distance from the fireside of the tube sheet to the fireside of the back connection plate, inches P = maximum allowable working pressure, pounds per square inch p = pitch of supporting bolts, inches D1 = distance between girders from center to center, inches d = depth of girder, inches C = 7,000 when girder is fitted with one supporting bolt C = 10,000 when the girder is fitted with two or three supporting bolts C = 11,000 when the girder is fitted with four or five supporting bolts C = 11,500 when the girder is fitted with six or seven supporting bolts C = 12,000 when the girder is fitted with eight or more supporting bolts 35.2 When this form of staying is to be placed on a boiler, the diameter of which is intermediate to or below the diameters given in Table PFT-35, the tabular values for the next higher diameter shall govern. Rivets of the same diameter as used in the longitudinal joints of the boiler shall be used to attach the structural shapes to the head and to connect the outstanding legs. 35.3 The rivets attaching structural shapes to heads shall be spaced not over 4 in. apart. The centers of the end rivets shall be not over 3 in. from the ends of the structural shape. The rivets through the outstanding legs shall be spaced not over 8 in. apart; the centers of the end rivets shall be not more than 4 in. from the ends of the structural shapes. The ends of the structural shapes shall be considered those of the outstanding legs and the lengths shall be such that their ends overlap a circle 3 in. inside the inner surface of the shell as shown in Figure PFT-35. CROWN BARS AND GIRDER STAYS Example: Given W=34 in., p=7.5 in., D1=7.75 in., d=7.5 in., t=2 in., three stays per girder, C=10,000; then substitute the formula: �� Sling stays, if used between crown bars and boiler shell or wrapper sheet, shall be proportioned so as to carry the entire load without considering the strength of the crown bars. 36.2 In a form of reinforcement for crown sheets where the top sheet of the firebox is a 331 NATIONAL BOARD INSPECTION CODE semicircle and the top part of the circle not exceeding 120 deg. in arc is reinforced by arch bars extending over the top and down below the top row of staybolts at the sides of the furnace beneath the semicircular crown sheet, these arch bars being riveted to the waterside through thimbles, the maximum allowable working pressure shall be determined by adding to the maximum allowable working pressure for a plain circular furnace of the same thickness, diameter, and length determined by the formula in PFT-14, the pressure P1 determined from the following formula which is a modification of the first formula in PFT-15: �� where, b = net width of crown bar, inches d = depth of crown bar, inches D1 = longitudinal spacing of crown bar which shall not exceed twice the maximum allowable staybolt pitch, inches D = two times the radius of the crown sheet, inches provided that the maximum allowable working pressure must not exceed that determined by the formula for furnaces of the Adamson type, in PFT-16 when L is made equal to D1 , and also provided that the diameter of the holes for the staybolts in the crown bars does not exceed 1/3 b, and the cross-sectional areas of the crown bars is not less than 4 sq. in. PG-46 governs the spacing of the staybolts, rivets, or bolts attaching the sheet to the bars, and PFT-23.4, the size of the staybolts, rivets or bolts. For constructions in which the crown sheet is not semicircular, or in which other features differ from those specified above, a test shall be made in accordance with PG-101 and the working pressure shall be based thereon. PFT-37 TRUNCATED CONE SHAPED COMBUSTION CHAMBERS OF VERTICAL TUBULAR BOILERS 37.1 Upper combustion chambers of vertical submerged tubular boilers made in the shape of a frustrum of a cone when not over 38 in. diameter at the large end may be used without stays if computed by the rule of plain cylindrical furnaces in PFT-14, making D in the formula equal to the diameter at the large end, provided that the longitudinal joint conforms to the requirements of PFT-14. 37.2 When over 38 in. in diameter at the large end, that portion which is over 30 in. in diameter shall be fully supported by staybolts or gussets. If supported by staybolts, PFT23.4 shall apply. If supported by gussets the spacing of the rivets attaching the gussets to the cone sheet shall not exceed the staybolt spacing given in PFT-23.4. The top row of staybolts or rivets shall be at a point where the cone top is 30 in. or less in diameter. In calculating the pressure permissible on the unstayed portion of the cone, the vertical distance between the horizontal planes passing through the centers of the rivets at the cone top and through the center of the top row of staybolts shall be as L in PFT-14.4 and D in that paragraph shall be the inside diameter at the center of the top row of staybolts. PFT-38 STAY TUBES 38.1 When stay tubes are used in multitubular boilers to give support to the tube plates, the sectional area of such stay tubes may be determined as follows: � �� Total section of stay tubes, sq. in. = 36.3 Cast iron supporting lugs, legs, or ends shall not be used. 332 � where, A = area of that portion of tube plate containing the tubes, square inches a = aggregate area of holes in the tube plate, square inches APPENDIX C — HISTORICAL BOILERS TABLE PFT-38 — Values of C For Determining Pitch of Stay Tubes Pitch of Stay Tubes in the Bounding Rows When Tubes Have No Nuts Outside of Plates When Tubes Are Fitted With Nuts Outside of Plates Where there are two plain tubes between two stay tubes 2.2 2.4 Where there is one plain tube between two stay tubes 2.6 2.8 Where every tube in the bounding rows is a stay tube and each alternate tube has a nut ... 3.2 P = maximum allowable working pressure, pounds per square inch S = maximum allowable stress value in the tubes, pounds per square inch (not to exceed 7,000 psi). 38.2 The pitch of stay tubes shall conform to the formula in PG-46, using the values of C as given in Table PFT-38. When the ends of tubes are not shielded from the action of flame or radiant heat, the values of C shall be reduced 20%. The tubes shall project about 1/4 in. at each end and be slightly flared. Stay tubes when threaded shall be not less than 3/16 in. in thickness at bottom of thread; nuts on stay tubes are not advised. For nest of tubes, C shall be taken as 2.5 and p as the mean pitch of stay tubes. For spaces between nests of tubes, p shall be taken as the horizontal distance from center to center of the bounding rows of tubes and C as given in Table PFT-38. DOORS AND OPENINGS PFT-39 RIVETED DOOR OPENINGS Doors in waterlegs may be attached by riveting provided the rules for riveting in Part PR and the rules for stayed surfaces in this Part are complied with. PFT-40 WELDED DOOR OPENINGS Arc or gas welding may be used in the fabrication of door holes provided the sheets are stayed around the opening in accordance with the requirements of PFT-26.7 and 26.8. The fit-up of the several parts of an arc or gas welded door opening shall be such that the maximum gap between the two plates to be joined by welding does not exceed 1/8 in. PFT-41 OPENINGS IN WRAPPER SHEETS Openings located in the curved portion of the wrapper sheet of a locomotive-type boiler shall be designed in accordance with the rules in PG-32. PFT-42 ACCESS AND FIRING DOORS The minimum size of an access door to be placed in a boiler setting shall be 12 in. x 16 in., or equivalent area; 11 in. to be the least dimension in any case. The minimum size of a fire door opening in an internally fired boiler in which the minimum furnace dimension is 24 in. or over shall be not less than 11 in. x 15 in. or 10 in. x 16 in. in size. A circular opening shall be not less than 15 in. in diameter. 333 NATIONAL BOARD INSPECTION CODE The bonnet or smoke hood of a vertical flue or tubular boiler shall be provided with an access opening at least 6 x 8 in. for the purpose of inspection and cleaning the top head of the boiler. PFT-43 LOCATION OF MANHOLES AND HANDHOLES 43.1 The manhole shall be located in the front head below the tubes of a horizontal-return tubular boiler 48 in. or over in diameter. Smaller boilers shall have either a manhole or a handhole below the tubes. There shall be a manhole in the upper part of the shell or head of a firetube boiler over 40 in. in diameter, except on a vertical firetube boiler, or except on internally fired boilers not over 48 in. in diameter. The manhole may be placed in the head of the dome. Smaller boilers shall have either a manhole or a handhole above the tubes. less than three additional handhole openings at the lower part of the waterleg. A submerged-tube type of vertical firetube boiler 24 in. or more in diameter shall have two or more additional handhole openings in the shell, in line with the underside of the upper tube sheet. 43.4 A vertical boiler, except of the watertube type, less than 24 in. in diameter, shall have in the shell a handhole opening at the waterline and two washout openings near the bottom in addition to the blowoff for washing out the boiler, except: 43.4.1 If of the internally fired type, it shall have a handhole opening in the shell in line with the crown sheet or lower tube sheet, in which case the handhole opening at the waterline may be omitted. 43.4.2 If of the submerged-tube type, it shall also have a handhole opening in the shell in line with the upper tube sheet in which case the handhole opening at the waterline may be omitted. Where plugs are used the minimum size shall be 1-1/2 in. and the requirements of PG-32 through PG-44 shall apply. 43.2 A traction, portable, or stationary boiler of the locomotive type shall have not less than six handholes or washout plugs located as follows: One in the rear head below the tubes; one in the front head at or about the line of the crown sheet; four in the lower part of the waterleg; also, where possible, one near the throat sheet. If the front head is obstructed by a smokebox, the handhole may be inserted in either side sheet at or about the line of the crown sheet. 43.3 A vertical boiler, except watertube type and boilers of steam fire engines and boilers less than 24 in. in diameter, shall have not less than four handhole openings in the shell located as follows: One at or about the waterline or opposite the fusible plug when used; three at or about the line of the crown sheet or lower tube sheet, and if internally fired not 43.5 If a vertical-type boiler is equipped with manholes or other access openings, through which adequate inspection may be made, the required handhole and/or inspection openings at the waterline and for the tube sheets may be omitted. 43.6 A vertical firetube boiler of a steam fire engine shall have at least three washout openings located as follows: One at or about the line of the crown sheet, two at the lower part of the waterleg. 43.7 A boiler of the scotch type shall have a handhole or washout plug in the front head below or on each side of the furnace, or on each side of the shell near the front head, a handhole or a washout plug on the bottom of the shell, an opening to inspect the top of the furnace, and an inspection opening above 334 APPENDIX C — HISTORICAL BOILERS the top row of tubes. Scotch marine boilers (wet-back type) shall also have an opening for inspection of the water space at the rear of the combustion chamber. PFT-44 OPENING BETWEEN BOILER AND SAFETY VALVE The opening or connection between the boiler and the safety valve shall have at least the area of the valve inlet. In the case of firetube boilers, the openings in the boilers for safety valves or safety relief valves shall be not less than given in Table PFT-44, except firetube boilers used for waste heat purposes only, not equipped for direct firing, need not meet the requirements of Table PFT-44 provided the rated steaming capacity is stamped on the boiler and safety valves or safety relief valves of the required relieving capacity are supplied such that the provisions of PG-67.2 are satisfied. No valve of any description shall be placed between the required safety valve or safety relief valve or valves and the boiler, nor on the discharge pipe between the safety valve or safety relief valve and the atmosphere. When a discharge pipe is used, the cross-sectional area shall be not less than the full area of the valve outlet or of the total of the areas of the valve outlets discharging thereinto and shall be as short and straight as possible and so arranged as to avoid undue stresses on the valve or valves. DOMES which the product of the inside diameter in inches and the maximum allowable working pressure in pounds per square inch does not exceed 4,000, its flange may be single-riveted to the shell and the longitudinal joint may be of the lap type, provided it is computed with a factor of safety of not less than 8. The longitudinal joint of a dome may be buttwelded and the dome flange may be double full fillet lap-welded to the shell, in place of riveting if the welding complies fully with the requirements for welding in Part PW. Radiographic examination of the fillet welds may be omitted. The opening shall be reinforced in accordance with PG-32 through PG-44. 45.2 The joints of a dome may be welded and the dome welded to the shell if the welding complies fully with the requirements for welding in Part PW. The opening shall be reinforced in accordance with PG-32 through PG-44. 45.3 When a dome is located on the barrel of a locomotive-type boiler or on the shell of a horizontal-return tubular boiler, the diameter of the dome shall not exceed six-tenths the diameter of the shell or barrel of the boiler unless the portion of the barrel or shell under the dome (the neutral sheet) is stayed to the head or shell of the dome by stays which conform in spacing and size to the requirements given in PG-46 and Table PG-23.1. With such stayed construction the diameter of a dome located on the barrel or shell of a boiler is limited to eight-tenths of the barrel or shell diameter. REQUIREMENTS FOR DOMES 45.4 All domes shall be so arranged that any water can drain back into the boiler. 45.1 The longitudinal joint of a riveted dome 24 in. or over in inside diameter shall be of butt- and double-strap construction, or the dome may be made without a seam of one piece of steel pressed into shape; and its flange shall be double-riveted to the shell. In the case of a dome less than 24 in. in diameter, for 45.5 Flanges of domes shall be formed with a corner radius, measured on the inside, of at least twice the thickness of the plate for plates 1 in. in thickness or less, and at least 3 times the thickness of the plate for plates over 1 in. in thickness. PFT-45 335 6.348 5.000 3.168 3.174 2.500 1.584 1.166 0.924 0.767 0.655 0.572 0.508 0.457 0.415 16 25 50 75 100 125 150 175 200 225 250 336 �� 1.827 1.659 2.621 2.289 2.033 4.663 3.697 3.067 12.695 10.000 6.338 400 2.284 2.074 3.276 2.862 2.541 5.828 4.621 3.834 15.869 12.498 7.920 500 2.740 2.489 3.932 3.435 3.049 6.995 5.546 4.600 19.043 15.000 9.504 600 0.622 0.824 1.049 1.380 1.610 1/2 3/4 1 1-1/4 1-1/2 0.304 0.533 0.864 1.495 2.036 Internal Area, sq. in. 2 2-1/2 3 3-1/2 Nominal Pipe Size, in. 5.481 4.978 7.863 6.870 6.099 13.989 11.092 9.201 38.086 30.000 19.007 1200 6.394 5.807 9.174 8.015 7.115 16.320 12.940 10.734 44.435 35.000 22.175 1400 7.308 6.637 10.484 9.158 8.132 18.652 14.789 12.267 50.738 40.000 25.354 1600 8.221 7.466 11.795 10.305 9.148 20.983 16.637 13.800 57.130 44.992 28.510 1800 9.134 8.296 13.106 11.450 10.164 23.314 18.486 15.334 63.478 49.992 31.678 2000 11.417 10.370 16.382 14.312 12.706 29.143 23.106 19.116 79.347 62.489 39.599 2500 13.702 12.444 19.658 17.175 15.247 34.972 27.729 23.000 95.216 74.987 47.517 3000 1.9183 1.7422 2.752 2.404 2.1345 4.896 3.882 3.220 13.330 10.498 6.655 V 2.067 2.469 3.068 3.548 3.355 4.788 7.393 9.886 Internal Area, sq., in. 4 5 6 8 Nominal Pipe Size, in. 4.026 5.047 6.065 8.071 Internal Diameter 12.730 20.006 28.891 51.161 Internal Area, sq. in. NOTE: number and size of opening shall provide for not less than the area given. Intermediate values may be interpolated. With flanged openings, use internal area for determining diameter. 4.567 4.148 6.553 5.725 5.082 11.657 9.243 7.667 31.739 24.996 15.839 1000 Internal Diameter 3.654 3.318 5.242 4.579 4.066 9.326 7.394 6.134 25.392 20.000 12.677 800 Boiler Heating Surface, sq. ft. total area of openings, square inches boiler heating surface, square feet specific volume of steam in cubic feet per pound at maximum allowable working pressure Internal Diameter A = H = V = �� 1.370 1.244 1.966 1.718 1.525 3.497 2.773 2.300 9.522 7.499 4.752 300 Nominal Pipe Size, in. where based on formula 0.913 0.830 1.311 1.145 1.016 2.331 1.849 1.533 200 Gage Pressure, psi 100 TABLE PFT-44 — Minimum Total Areas of Openings (Square Inches) in Firetube Boilers for Safety Valve Connections NATIONAL BOARD INSPECTION CODE APPENDIX C — HISTORICAL BOILERS SETTING PFT-46 METHOD OF SUPPORT 46.1 The design and attachment of lugs, hangers, saddles, and other supports shall meet the requirements of PG-22.1 and PG-55. FIGURE PFT-46.1 — Spacing of Supporting Lugs in Pairs on HorizontalReturn Tubular Boiler 2" Maximum 46.2 In applying the requirements of 46.1, localized stresses due to concentrated support loads, temperature changes, and restraint against dilation of the boiler due to pressure shall be provided for. Lugs, brackets, saddles, and pads shall conform satisfactorily to the shape of the shell or surface to which they are attached or with which they are in contact. 46.3 A horizontal-return tubular boiler over 72 in. in diameter shall be supported from steel hangers by the outside-suspension type of setting, independent of the furnace side walls. The hangers shall be so designed that the load is properly distributed between the rivets attaching them to the shell and so that no more than two of these rivets come in the same longitudinal line on each hanger. The distance girthwise of the boiler from the centers of the bottom rivets to the centers of the top rivets attaching the hangers shall be not less than 12 in. The other rivets used shall be spaced evenly between these points. FIGURE PFT-46.2 — Welded Bracket Connection for Horizontal-Return Tubular Boilers B “R” B Dimension “T” not less than 1% of Boiler Diameter 2 12 “T” “T” min. 46.4 The horizontal-return tubular boiler, 14 ft. or more in length, or over 54 in. and up 3 4 T 3 4T Section B-B 337 Dimension “R” not less than 1-1/2 x Diameter of Hole 2 ma 0 x. 45.7 In a locomotive-type boiler with a dome on a tapered course, the maximum allowable diameter of the dome shall be based on that diameter of the tapered course which intersects the axis or centerline of the dome. to and including 72 in. in diameter, shall be supported by the outside-suspension type of setting as specified in PFT-46.3, or at four points by not less than eight steel or cast iron lugs set in pairs. A horizontal-return tubular boiler up to and including 54 in. in diameter shall be supported by the outside-suspension type of setting as specified in PFT-46.3, or by not less than two steel or cast iron lugs on each side. The distance girthwise of the boiler from the centers of the bottom rivets to the centers of the top rivets attaching the hangers shall be not less than the square of the shell diameter divided by 675. If more than four lugs are used they shall be set in four pairs, 20 max . 45.6 Domes and manhole frames attached to shells or heads of boilers shall be designed in accordance with PG-32 through PG-44, with the additional requirement that the maximum allowable stress value in tension of rivets in manhole frames having a thickness of 7/8 in. or less and of rivets in domes flanges shall not exceed 7,200 psi. 3T 4 NATIONAL BOARD INSPECTION CODE the lugs of each pair to be spaced not over 2 in. apart and the load to be equalized between them (see Figure PFT-46.1). If the boiler is supported on structural steel work, the steel supporting members shall be so located or insulated that heat from the furnace cannot impair their strength. 46.5 Figure PFT-46.2 illustrates an acceptable design of hanger bracket for welded attachment to welded horizontal-return tubular boilers with the additional requirement that the hanger pin be located at the vertical center line over the center of a welded contact surface. The bracket plates shall be spaced at least 2-1/2 in. apart, but this dimension shall be increased if necessary to permit access for the welding operation. 46.6 Wet-bottom stationary boilers shall be supported so as to have a minimum clearance of 12 in. between the underside of the wet-bottom and the floor to facilitate inspection. Other types of firetube boilers set horizontally shall be supported so that they have a minimum clearance of 12 in. between the metal surface of the shell and the floor. Boiler insulation, saddles, or other supports shall be arranged so that inspection openings are readily accessible. PIPING, FITTINGS, AND APPLIANCES PFT-47 WATER GLASSES Boilers of the horizontal firetube type shall be so set that when the water is at the lowest reading in the water gage glass there shall be at least 3 in. of water over the highest point of the tubes, flues or crown sheet. PFT-48 discharge at about three-fifths the length from the end of the boiler which is subjected to the hottest gases of the furnace (except a horizontal-return tubular boiler equipped with an auxiliary feedwater heating and circulating device), above the central row of tubes. The feed pipe shall be carried through the head or shell farthest from the point of discharge of the feedwater in the manner specified for a surface blowoff in PG-59.3.2, and be securely fastened inside the shell above the tubes. 48.2 In vertical tubular boilers having tubes 4 ft. or less in length, the feedwater shall be introduced at a point not less than 12 in. above the crown sheet. When the boiler is under pressure, feedwater shall not be introduced through the openings or connections used for the water column, the water gage glass, or the gage cocks. In closed systems the water may be introduced through any opening when the boiler is not under pressure. PFT-49 BLOWOFF PIPING 49.1 Blowoff piping of firetube boilers which are exposed to products of combustion shall be attached by screwing into a tapped opening with a screw fitting or valve at the other end. 49.2 Blowoff piping of firetube boilers which are not exposed to products of combustion may be attached by any method provided in this Section except by expanding into grooved holes. 49.3 The bottom blowoff pipes of traction and portable boilers shall have at least one slow or quick-opening blowoff valve or cock conforming to the requirements of PG-59.5.3.3. FEED PIPING 48.1 When a horizontal-return tubular boiler exceeds 40 in. in diameter, the feedwater shall 338 APPENDIX C — HISTORICAL BOILERS APPENDIX — EXPLANATORY OF THE CODE AND CONTAINING MATTER WHICH IS NOT MANDATORY UNLESS SPECIFICALLY REFERRED TO IN THE RULES OF THE CODE EFFICIENCY OF JOINTS A-1 EFFICIENCY OF RIVETED JOINTS The ratio which the strength of a unit length of a riveted joint has to the same unit length of the solid plate is known as the efficiency of the joint and shall be calculated by the general method illustrated in the following examples: TS = tensile strength stamped on plate, pounds per square inch t = thickness of plate, inches b = thickness of buttstrap, inches P = pitch of rivets, inches, on row having greatest pitch d = diameter of rivet after driving, inches = diameter of rivet hole a = cross-sectional area of rivet after driving, square inches s = shearing strength of rivet in single shear, pounds per square inch, as given in PG-23.2 S = shearing strength of rivet in double shear, pounds per square inch, as given in PG-23.2 c = crushing strength of mild steel, pounds per square inch, as given in PG-23.3 n = number of rivets in single shear in a unit length of joint N = number of rivets in double shear in a unit length of joint A-2 A = strength of solid plate = P x t x TS B = strength of plate between rivet holes (P - d) t x TS C = shearing strength of one rivet in single shear = n x s x a D = crushing strength of plate in front of a rivet = d x t x c Divide B, C, or D (whichever is the least) by A, and the quotient will be the efficiency of a single-riveted lap joint as shown in Figure A-1. TS = 55,000 psi t = 1/4 in. = 0.25 in. P = 1-5/8 in. = 1.625 in. d = 11/16 in. = 0.6875 in. a = 0.3712 sq. in. s = 44,000 psi c = 95,000 psi A = 1.625 x 0.25 x 55,000 = 22,343 B = (1.625–0.6875)0.25 x 55,000 = 12,890 C = 1 x 44,000 x 0.3712 = 16,332 D = 0.6875 x 0.25 x 95,000 = 16,328 �� FIGURE A-1 — Example of Lap Joint, Longitudinal, or Circumferential, Single Riveted P EXAMPLE Lap joint, longitudinal or circumferential, single riveted. 339 NATIONAL BOARD INSPECTION CODE A-3 EXAMPLE A-4 Lap joint, longitudinal or circumferential, double riveted. EXAMPLE Butt- and double-strap joint, double riveted. A = strength of solid plate = P x t x TS B = strength of plate between rivet holes (P–d) t x TS C = shearing strength of two rivets in single shear = n x s x a D = crushing strength of plate in front of two rivets = n x d x t x c Divide B, C, or D (whichever is the least) by A, and the quotient will be the efficiency of a double-riveted lap joint as shown in Figure A-2. TS = 55,000 psi t = 5/16 in. = 0.3125 in. P = 2 7/8 in. = 2.875 in. d = 3/4 in. = 0.75 in. a = 0.4418 sq. in. s = 44,000 psi c = 95,000 psi A = 2.875 x 0.3125 x 55,000 = 49,414 B = (2.875–0.75) 0.3125 x 55,000 = 36,523 C = 2 x 44,000 x 0.4418 = 38,878 D = 2 x 0.75 x 0.3125 x 95,000 = 44,531 �� FIGURE A-2 — Example of Lap Joint, Longitudinal, or Circumferential, Double Riveted A = strength of solid plate = P x t x TS B = strength of plate between rivet holes in the outer row = (P–d) t x TS C = shearing strength of two rivets in double shear, plus the shearing strength of one rivet in single shear =NxSxa+nxsxa D = strength of plate between rivet holes in the second row, plus the shearing strength of one rivet in single shear in the outer row = (P–2d) t x TS + n xsxa E = strength of plate between rivet holes in the second row, plus the crushing strength of buttstrap in front of one rivet in the outer row = (P - 2d) t x TS + d x b x c F = crushing strength of plate in front of two rivets, plus the crushing strength of buttstrap in front of one rivet = N x d x t x c + n x d x b x c G = crushing strength of plate in front of two rivets, plus the shearing strength of one rivet in single shear =Nxdxtxc +nxsxa H = strength of buttstraps between rivet holes in the inner row = (P–2d) 2b x TS. This method of failure is not possible for thicknesses of buttstraps required by these rules and the FIGURE A-3 — Example of Butt- and Double-Strap Joint, Double Riveted P P 340 APPENDIX C — HISTORICAL BOILERS computation need only be made for old boilers in which thin buttstraps have been used. For this reason this method of failure will not be considered in other joints. A-5 Butt- and double-strap joint, triple riveted. A = strength of solid plate = P x t x TS B = strength of plate between rivet holes in the outer row = (P–d)t x TS C = shearing strength of four rivets in double shear, plus the shearing strength of one rivet in single shear =NxSxa+nxsxa D = strength of plate between rivet holes in the second row, plus the shearing strength of one rivet in single shear in the outer row = (P–2d)t x TS + n xsxa E = strength of plate between rivet holes in the second row, plus the crushing strength of buttstrap in front of one rivet in the outer row = (P–2d)t x TS +dxbxc F = crushing strength of plate in front of four rivets, plus the crushing strength of buttstrap in front of one rivet = N x d x t x c + n x d x b x c G = crushing strength of plate in front of four rivets, plus the shearing strength of one rivet in single shear =Nxdxtxc+nxs xa Divide B, C, D, E, F, G, or H (whichever is the least) by A, and the quotient will be the efficiency of a butt- and double-strap joint, double riveted, as shown in Figure A-3. TS = 55,000 psi t = 3/8 in. = 0.375 in. b = 5/16 in. = 0.3125 in. P = 4-7/8 in. = 4.875 in. d = 7/8 in. = 0.875 in. a = 0.6013 sq. in. s = 44,000 psi S = 88,000 psi c = 95,000 psi Number of rivets in single shear in a unit length of joint = 1. Number of rivets in double shear in a unit length of joint = 2. A = 4.875 x 0.375 x 55,000 = 100,547 B = (4.875–0.875)0.375 x 55,000 = 82,500 C = 2 x 88,000 x 0.6103 + 1 x 44,000 x 0.6013 = 132,286 D = (4.875–2 x 0.857) 0.375 x 55,000 + 1 x 44,000 x 0.6013 = 90,910 E = (4.875–2 x 0.875) 0.375 x 55,000 + 0.875 x 0.3125 x 95,000 = 90,499 F = 2 x 0.875 x 0.375 x 95,000 + 1 x 0.875 x 0.3125 x 95,000 = 88,320 G = 2 x 0.875 x 0.375 x 95,000 + 1 x 44,000 x 0.6013 = 88,800 EXAMPLE Divide B, C, D, E, F, or G (whichever is the least) by A, and the quotient will be the efficiency of a butt- and double-strap joint, triple riveted as shown in Figure A-4. �� 341 TS = 55,000 psi t = 3/8 in. = 0.375 in. b = 5/16 in. = 0.3125 in. P = 6-1/2 in. = 6.5 in. d = 13/16 in. = 0.8125 in. a = 0.5185 sq. in. s = 44,000 psi S = 88,000 psi c = 95,000 psi NATIONAL BOARD INSPECTION CODE Number of rivets in single shear in a unit length of joint = 1. Number of rivets in double shear in a unit length of joint = 4. A-6 EXAMPLE Butt- and double-strap joint, quadruple riveted. A = 6.5 x 0.375 x 55,000 = 134,062 B = (6.5–0.8125) 0.375 x 55,000 = 117,304 C = 4 x 88,000 x 0.5185 + 1 x 44,000 x 0.5185 = 205,326 D = (6.5–2 x 0.8125) 0.375 x 55,000 + 1 x 44,000 x 0.5185 = 123,360 E = (6.5–2 x 0.8125)0.375 x 55,000 + 0.8125 x 0.3125 x 95,000 = 124,667 F = 4 x 0.8125 x 0.375 x 95,000 + 1 x 0.8125 x 0.3125 x 95,000 = 139,902 G = 4 x 0.8125 x 0.375 x 95,000 + 1 x 44,000 x 0.5185 = 138,595 �� FIGURE A-5 — Example of Butt- and Double-Strap Joint, Quadruple Riveted P P FIGURE A-4 — Example of Butt- and Double-Strap Joint, Triple Riveted A = strength of solid plate = P x t x TS B = strength of plate between rivet holes in the outer row = (P–d)t x TS C = shearing strength of eight rivets in double shear, plus the shearing strength of three rivets in single shear = N x S x a + n x s x a D = strength of plate between rivet holes in the second row, plus the shearing strength of one rivet in single shear in the outer row = (P–2d)t x TS + 1 xsxa E = strength of plate between rivet holes in the third row, plus the shearing strength of two rivets in the second row in single shear and one rivet in single shear in the outer row = (P–4d)t x TS + n x s x a 342 APPENDIX C — HISTORICAL BOILERS F = strength of plate between rivet holes in the second row, plus the crushing strength of buttstrap in front of one rivet in the outer row = (P–2d)t x TS +dxbxc G = strength of plate between rivet holes in the third row, plus the crushing strength of buttstrap in front of two rivets in the second row and one rivet in the outer row = (P–4d)t x TS + n x d x b x c H = crushing strength of plate in front of eight rivets, plus the crushing strength of buttstrap in front of three rivets = N x d x t x c + n x d x b x c I = crushing strength of plate in front of eight rivets, plus the shearing strength of two rivets in the second row and one rivet in the outer row, in single shear = N x d x t x c + n x s xa Divide B, C, D, E, F, G, H, or I (whichever is the least) by A, and the quotient will be the efficiency of a butt- and double-strap joint, quadruple riveted, as shown in Figure A-5. TS = 55,000 psi t = 1/2 in. = 0.5 in. b = 7/16 in. = 0.4375 in. P = 15 in. d = 15/16 in. = 0.9375 in. a = 0.6903 sq. in. s = 44,000 psi S = 88,000 psi c = 95,000 psi D = (15–2 x 0.9375)0.5 x 55,000 + 1 x 44,000 x 0.6903 = 391,310 E = (15–4 x 0.9375)0.5 x 55,000 + 3 x 44,000 x 0.6903 = 400,494 F = (15–2 x 0.9375)0.5 x 55,000 + 0.9375 x 0.4375 x 95,000 = 399,902 G = (15–4 x 0.9375) 0.5 x 55,000 + 3 x 0.9375 x 0.4375 x 95,000 = 426,269 H = 8 x 0.9375 x 0.5 x 95,000 + 3 x 0.9375 x 0.4375 x 95,000 = 473,145 I = 8 x 0.9375 x 0.5 x 95,000 + 3 x 44,000 x 0.6903 = 447,369 �� A-7 Figure A-6 and A-7 illustrate other joints that may be used in which eccentric stresses are avoided. The butt- and double-strap joint with straps of equal width shown in Figure A-6 may be so designed that it will have an efficiency of from 82 to 84 percent and the sawtooth joint shown in Figure A-7 so that it will have an efficiency of from 92 to 94 percent. BRACED AND STAYED SURFACES A-8 Number of rivets in single shear in a unit length of joint = 3. The allowable loads based on the net crosssectional area of staybolts with V-threads are computed from the following formulas. The use of Whitworth threads with other pitches is permissible. Number of rivets in double shear in a unit length of joint = 8. The formula for the diameter of a staybolt at the bottom of a V-thread is: A = 15 x 0.5 x 55,000 = 412,500 B = (15–0.9375)0.5 x 55,000 = 386,718 C = 8 x 88,000 x 0.6903 + 3 x 44,000 x 0.6903 = 577,090 343 D–(P x 1.732) = d NATIONAL BOARD INSPECTION CODE where, D = diameter of staybolt over the threads, inches P = pitch of threads, inches = 1/number of threads per inch d = diameter of staybolt at bottom of threads, inches 1.732= a constant A-9 When ANSI Standard threads are used the formula becomes Table A-4 gives the net areas of segments of heads for use in computing stays. Table A-3 shows the allowable loads on net cross-sectional areas of round stays or braces. A-10 D–(P x 1.732) = d Tables A-1 and A-2 give the allowable loads on net cross-sectional areas for staybolts with V-threads having 12 and 10 threads per in. FIGURE A-6 — Illustration of Butt- and Double-Strap Jint with Straps of Equal Width FIGURE A-7 — Illustration of Butt- and Double-Strap Joint of the Sawtooth Type 344 APPENDIX C — HISTORICAL BOILERS TABLE A-1 — Allowable Loads on Staybolts with V Threads, 12 Threads Per Inch Outside diameter of Staybolts, in. Diameter at Bottom of Thread, in. Net Cross-Sectional Area (at Bottom of Thread). sq. in. Allowable Load at 7500 lb Stress per sq. in. 3/4 13/16 7/8 0.7500 0.8125 0.8750 0.6057 0.6682 0.7307 0.288 0.351 0.419 2160 2632 3142 15/16 1 1-1/16 0.9375 1.0000 1.0625 0.7932 0.8557 0.9182 0.494 0.575 0.662 3705 4312 4965 1-1/8 1-3/16 1-1/4 1.1250 1.1875 1.2500 0.9807 1.0432 1.1057 0.755 0.855 0.960 5662 6142 7200 1-5/16 1-3/8 1-7/16 1-1/2 1.3125 1.3750 1.4375 1.5000 1.1682 1.2307 1.2932 1.3557 1.072 1.190 1.313 1.444 8040 8925 9849 10830 TABLE A-2 — Allowable Loads on Staybolts with V Threads, 10 Threads Per Inch Outside diameter of Staybolts, in. Diameter at Bottom of Thread, in. Net Cross-Sectional Area (at Bottom of Thread). sq. in. Allowable Load at 7500 lb Stress per sq. in. 1-1/4 1-5/16 1-3/8 1-7/16 1-1/2 1-9/16 1-5/8 1.0768 1.1393 1.2018 1.2643 1.3268 1.3893 1.4518 0.911 1.019 1.134 1.255 1.382 1.515 1.655 6832 7642 8505 9412 10365 11362 12412 1.2500 1.3125 1.3750 1.4375 1.5000 1.5625 1.6250 345 NATIONAL BOARD INSPECTION CODE TABLE A-3 — Allowable Loads on Round Braces or Stay Rods Allowable stress, in psi, on Net Cross-Sectional Area Minimum Diameter of Circular Stay, in. Net Cross-Sectional Area of Stay, sq. in. 6000 8500 9500 Allowable load, in lb., on Net Cross-Sectional Area 1 1-1/16 1-1/8 1.0000 1.0625 1.1250 0.7854 0.8866 0.9940 4712 5320 5964 6676 7536 8449 7462 8423 9443 1-3/16 1-1/4 1-5/16 1.1875 1.2500 1.3125 1.1075 1.2272 1.3530 6645 7363 8118 9414 10431 11501 10521 11658 12854 1-3/8 1-7/16 1-1/2 1.3750 1.4375 1.5000 1.4849 1.6230 1.7671 8909 9738 10603 12622 13796 15020 14107 15419 16787 1-9/16 1-5/8 1-11/16 1.5625 1.6250 1.6875 1.9175 2.0739 2.2365 11505 12443 13419 16298 17628 19010 18216 19702 21247 1-3/4 1-13/16 1-7/8 1.7500 1.8125 1.8750 2.4053 2.5802 2.7612 14432 15481 16567 20445 21932 23470 22852 24512 26231 1-15/16 2 2-1/8 1.9375 2.0000 2.1250 2.9483 3.1416 3.5466 17690 18850 21280 25061 26704 30147 28009 29845 33693 2-1/4 2-3/8 2-1/2 2.2500 2.3750 2.500 3.9761 4.4301 4.9087 23857 26580 29452 33797 37656 41724 37773 42086 46632 2-5/8 2-3/4 2-7/8 3 2.6250 2.7500 2.8750 3.0000 5.4119 5.9396 6.4918 7.0686 32471 35638 38951 42412 46001 50487 55181 60083 51413 56426 61673 67152 346 APPENDIX C — HISTORICAL BOILERS TABLE A-4 — Net Areas of Segments of Heads Where d, as Given in PFT-31.1 and PFT-31.3 is Equal t0o 3 inches Height From Tubes to Shell, in. 24 30 36 42 Diameter of Boiler, in. 48 54 60 66 Area to Be Stayed, sq. in. 72 78 84 90 96 8 8-1/2 9 9-1/2 10 28 35 42 50 57 33 41 49 58 68 37 46 56 66 77 40 51 62 70 85 43 55 67 80 93 47 59 72 86 99 51 63 76 91 106 53 66 82 96 112 55 70 86 101 117 58 74 90 105 123 60 76 92 111 129 63 80 95 116 132 65 82 98 119 137 10-1/2 11 11-1/2 12 12-1/2 66 74 83 91 ... 78 88 99 109 120 89 100 112 125 138 98 111 124 139 153 107 121 137 151 167 114 130 146 163 180 123 138 156 174 193 131 147 165 184 204 135 155 173 194 216 142 161 181 203 224 147 169 189 213 234 153 174 196 219 243 160 183 204 230 252 13 13-1/2 14 14-1/2 15 ... ... ... ... ... 132 143 155 167 178 151 164 178 192 206 168 183 199 215 231 183 200 217 235 252 197 216 234 254 273 211 230 250 271 291 224 246 266 287 309 235 258 280 303 326 247 270 294 318 343 256 282 305 333 357 267 293 319 345 372 279 302 331 360 386 15-1/2 16 16-1/2 17 17-1/2 ... ... ... ... ... ... ... ... ... ... 220 235 249 264 ... 247 263 281 297 314 271 289 308 326 345 291 312 332 353 374 312 334 357 378 400 332 355 380 402 426 350 374 399 425 449 368 394 420 447 471 382 411 436 467 494 400 423 457 486 516 417 443 475 502 536 18 18-1/2 19 19-1/2 20 ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... 331 349 366 384 401 365 384 404 424 444 396 417 439 461 483 424 448 470 496 519 450 476 500 528 552 476 501 529 558 583 500 526 555 584 613 520 552 580 613 642 543 577 604 641 667 564 598 631 663 699 20-1/2 21 21-1/2 22 22-1/2 ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... 464 485 505 526 ... 505 528 551 574 597 543 568 594 618 643 578 604 632 658 687 613 640 669 697 726 643 673 703 734 765 675 705 739 769 800 706 733 766 800 835 729 766 797 835 867 23 23-1/2 24 24-1/2 25 ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... 620 642 667 689 714 668 695 719 745 771 713 740 768 797 825 754 784 814 843 875 796 827 859 892 922 830 866 897 934 966 869 904 939 975 1010 906 945 978 1018 1051 25-1/2 26 26-1/2 27 27-1/2 ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... 737 761 ... ... ... 798 824 850 877 904 855 882 909 939 968 907 936 968 998 1030 956 987 1024 1053 1089 1003 1035 1073 1106 1145 1047 1083 1120 1157 1195 1092 1126 1167 1202 1243 28 28-1/2 29 29-1/2 30 ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... 930 ... ... ... ... 997 1028 1056 1084 1115 1060 1092 1123 1155 1187 1120 1157 1187 1221 1255 1177 1211 1248 1284 1321 1232 1270 1305 1347 1382 1279 1321 1360 1400 1442 30-1/2 31 31-1/2 32 32-1/2 ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... 1218 1252 1286 1317 ... 1290 1324 1359 1394 1430 1358 1394 1433 1467 1508 1424 1459 1496 1538 1575 1480 1523 1561 1650 1650 33 33-1/2 34 34-1/2 35 ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... 1465 1500 1536 ... ... 1542 1578 1617 1654 1692 1617 1655 1695 1735 1775 1687 1733 1770 1816 1856 35-1/2 36 36-1/2 37 ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... 1810 1857 ... ... 1900 1941 1984 2026 347 NATIONAL BOARD INSPECTION CODE 348 Recommended Guide for the Design of a Test System for Pressure Relief Devices in Compressible Fluid Service Appendix D 349 NATIONAL BOARD INSPECTION CODE APPENDIX D — RECOMMENDED GUIDE FOR THE DESIGN OF A TEST SYSTEM FOR PRESSURE RELIEF DEVICES IN COMPRESSIBLE FLUID SERVICE D-1000 INTRODUCTION D-1020 This non-mandatory appendix provides guidance for the design of a test system using compressible fluids (i.e., steam or air/gas) and permits the determination of pressure relief valve set pressure and valve operating characteristics such as blowdown. The size of the test vessel needed depends on the size of the valve, its set pressure, the design of the test system, and whether blowdown must be demonstrated. A repair organization may use the information provided in this appendix to determine the minimum size test vessel needed so that the measured performance is characteristic of the valve and not the test system. D-1010 GENERAL The National Board administrative rules and procedures for the “VR” Certificate of Authorization and symbol stamp require that pressure relief valves, after repair, be tested in accordance with the manufacturer’s recommendations and the applicable ASME Code. The purpose of this testing is to provide reasonable assurance that valves will perform according to design when they are returned to service. It is recognized that a full evaluation of the performance of some pressure relief valve designs requires testing at maximum allowable overpressure. However, it is beyond the scope of this appendix to define test equipment or facilities for such testing. D-1020 provides a glossary, D-2000 describes typical test equipment, and D-3000 provides data for estimating the size of test vessels required. GLOSSARY Accumulator: A vessel in which the test medium is stored or accumulated prior to its use for testing. Transient: A very short time, occurring over a brief time interval, maintained only for a short time interval as opposed to a steady state. Velocity distortion: The pressure decrease that occurs when fluid flows past the opening of a pressure sensing line. This is a distortion of the pressure that would be measured under the same conditions for a non or slowly moving fluid. Intervening: Coming between or inserted between, as between the test vessel and the valve being tested. Water head: The pressure adjustment that must be taken into account due to the weight of test media (in this case, steam) that is 0.433 psi per ft. (10 KPa per m.) added (subtracted) from the gage pressure for each foot the gage is below (above) the point at which the pressure is to be measured. D-2000 TEST SYSTEM DESCRIPTION An optimum configuration, particularly when the test medium source is of small capacity, is shown in Figure D-2000. The test medium flows from the pressure source, usually a compressor or boiler, to an accumulator. It then flows through a pressure-controlling valve into the test vessel, from which it is discharged, through the pressure relief valve mounted on the test vessel. The pressure-con- 350 APPENDIX D — RECOMMENDED GUIDE FOR THE DESIGN OF A TEST SYSTEM FOR PRESSURE RELIEF DEVICES IN COMPRESSIBLE FLUID SERVICE trolling valve is usually a globe valve, although any throttling valve is acceptable. If the pressure-controlling valve is of adequate size and can open quickly, large transient flows can be generated, increasing the pressure above the pressure relief valve set pressure, causing it to lift, and be sustained in its lifted condition. Figure D-2000-a shows a simpler test system in which the test vessel is pressurized directly from the pressure source without the use of an accumulator. In this configuration, flow-rates through the pressure relief valve and any consequent over-pressure are dependent on the flow generating capacity of the pressure source. In a test facility, the pressure relief valve is usually mounted on an isolating valve which should be of sufficient size that it will not choke flow to the pressure relief valve. There should be no intervening piping between the two (2) valves to avoid any unnecessary pressure drop between the test vessel and the pressure relief valve. The isolating valve and any adapter flanges or valve test nozzles must be designed to sustain pressure relief valve discharge forces, and so secured that these forces cannot be transmitted to the test vessel. This is especially important for larger valves set at pressures greater than 100 psig (700 KPa). The vessel should have a length-to-diameter ratio as low as is practical, and should be suitably anchored. Pressure sensing lines should be connected to the test vessel well away from any inlet or outlet connections where transient flow velocity during testing could cause erroneous pressure readings. When testing with steam, any water head which develops in the gage line must be taken into consideration. Any intervening piping between the test vessel and the pressure relief valve should be as short and as straight as possible and be of adequate size to minimize inlet pressure drop. In the case of steam, the equipment should be insulated and steam traps should be installed, as appropriate, to ensure that the test steam is dry, saturated steam with a minimum quality of 98%. Safety valves should be used to protect the test vessel and the accumulator. D-3000 TEST VESSEL SIZING DATA Recommended test vessel sizes are given in Figures D-3000 and D-3000-a for a configuration using one vessel fed directly from the source of the test medium. Figure D-3000 gives the test vessel size in cu. ft. vs. the valve orifice area in sq. in. for dry, saturated steam. Curves are shown for set pressures up to 500 psig (3.5 MPa) for three different blowdowns: 4%, 7% and 10%. The source is assumed to be capable of feeding the test vessel at 2500 lbs/hr. (1140 kg/hr) Figure D-3-000-a gives similar curves for air with a source capable of feeding the test vessel at 200 SCFM. For smaller valves, with effective orifices less than 1.28 sq. in., the size of the test vessel needed becomes less dependent on the flow capacity of the source. For these valves, a 15 cu. ft. (0.4 cu. m.) minimum size test vessel is recommended. This should allow the accurate measurement and setting of blowdown for small valves. This minimum size should also be adequate for determining set pressures of larger valves; however, larger test vessels must be used if blowdown is to be set accurately. It is recognized that there are practical limits on the size and maximum pressure of a test vessel used to demonstrate pressure relief valve operational characteristics. In such cases, determination of valve set pressure 351 NATIONAL BOARD INSPECTION CODE remains the only viable production and repair test option. The recommended minimum size test vessel (15 cu. ft. [0.4 cu. m.]) should be adequate for this purpose. 352 APPENDIX D — RECOMMENDED GUIDE FOR THE DESIGN OF A TEST SYSTEM FOR PRESSURE RELIEF DEVICES IN COMPRESSIBLE FLUID SERVICE FIGURE D-2000 — Schematic of Test Equipment with Accumulator �� FIGURE D-2000-a — Schematic of Test Equipment without Accumulator �� 353 NATIONAL BOARD INSPECTION CODE FIGURE D-3000 — Recommended Test Vessel Size, Test Medium: Steam 300 Valve Flow Areas (sq. mm. x 104) 200 150 4% –7 n ow d w o Bl n ow 7% d low B low B 10% 100 –8 • wn do –6 –5 –4 –3 50 Vessel Size (m3) VESSEL SIZE (CU. FT.) ■ ▼ 250 –2 ▼ 0 ■ –1 • 0 5 10 15 20 25 30 35 VALVE FLOW AREA (SQ. IN.) FIGURE D-3000-a — Recommended Test Vessel Size, Test Medium: Air or Gas Valve Flow Areas (sq. mm. x 104) 250 –7 ■ 150 –5 own owd Bl 7% own owd l B 10% 100 –8 • –4 –3 –2 50 0 ■ 0 –1 • 5 10 15 20 VALVE FLOW AREA (SQ. IN.) 354 25 30 35 Vessel Size (m3) VESSEL SIZE (CU. FT.) 200 Recommended Procedures for Repairing Pressure Relief Valves Appendix E 355 NATIONAL BOARD INSPECTION CODE APPENDIX E — RECOMMENDED PROCEDURES FOR REPAIRING PRESSURE RELIEF VALVES E-1000 INTRODUCTION It is essential that the repair organization establish basic, specific procedures for the repair of pressure relief valves. The purpose of these recommended procedures is to provide the repair organization with guidelines for this important aspect of valve repair. It is realized that there are many various types of valves and conditions under which they are repaired and, for this reason, the specific items in these recommended procedures may not apply, or they may be inadequate for each of those types or to the detailed repairs which may be required for each valve. See RA-2255(i). Part I contains recommended procedures for the repair of spring loaded pressure relief valves and Part II contains recommended procedures for the repair of pilot operated types of safety relief valves. E-2000 d. Check bonnet for venting on bellow type valves. e. Check appearance for any unusual damage, missing or misapplied parts. Note 2: If sufficient damage or other unusual conditions are detected that may pose a safety risk during preliminary testing, then proceed directly to step three. Note 3: Valves which are to be repaired in place proceed to step 3, unless preliminary testing has been authorized by the owner. 2. Preliminary Test as Received Information from the recommended preliminary performance test and subsequent disassembly and inspections will provide a basis for any repair interval change which may be necessary to ensure that the valve will function as intended. SPRING LOADED PRESSURE RELIEF VALVES a. Determine set pressure or Cold Differential Test Pressure (CDTP) in accordance with manufacturer ’s recommendations and appropriate ASME Code Section. Do not allow test pressure to exceed 116% of set pressure unless otherwise specified by the owner. A minimum of three tests is usually required to obtain consistent results. Note 1: Prior to removal of a valve from a system for a repair or any disassembly, ensure that all sources of pressure have been removed from the valve. 1. Visual Inspection as Received This information is to be recorded: a. Record user (customer) identification number. b. Complete nameplate data, plus any important information received from customer. Note 4: If results do not correlate with field performance, then steps to duplicate field conditions (fluid and temperature) may be necessary. c. Check external adjustment seals for warranty repair. 356 b. Record preliminary test results and test bench identification data. APPENDIX E — RECOMMENDED PROCEDURES FOR REPAIRING PRESSURE RELIEF VALVES 3. Disassembly c. Check disk assembly for cracks (NDE as applicable) or unusual wear. a. Remove cap and lever assembly, if applicable. d. Check spindle for trueness, bearing areas and thread condition. b. Remove release nut assembly, if applicable. e. Check guide for wear and galling. c. Loosen jam nut on adjusting (compression) screw. f. d. Record measurement and remove adjusting (compression) screw. g. Check ring pins for bent or broken pin and thread condition. e. Remove bonnet or yoke. h. Check bellows, if provided, for pinholes and corrosion. f. Remove spring and washers, and tag (identify) including upper and lower washers, as appropriate. g. Remove spindle and disk assembly. h. Remove ring pins. i. Record measurement and remove adjusting rings, nozzle and guide, as applicable. 4. Cleaning a. Wire all small parts together and clean by means of an abrasive (caution: do not use a cleaning method that will damage the parts.) b. Do not clean in a chemical solution except under acceptable circumstances. c. Protect seating surfaces and nameplates prior to cleaning. 5. Inspection a. Check spring for damage such as erosion, corrosion, cracking, breakage or compression below free height. b. Check nozzle for cracks (NDE as applicable) or unusual wear. i. Check adjusting ring(s) for worn threads and wear. Check flange gasket facings for wear and cuts. 6. Machining Machine nozzle and disk as necessary to the manufacturer’s critical dimension charts. 7. Lapping a. Machine or hand lap disk and nozzle to be sure of flatness. b. Lap bevel seats to a grey finish; then remachine disk or plug to the manufacturer’s critical dimension. 8. Adjusting Rings Install lower ring and guide ring to the same position they were when removed, or to manufacturer’s specifications. 9. Bearing Points Grind all bearing areas with grinding compound to make sure they are round and true. 10. Testing All test data is to be recorded. Testing will be done in accordance with manufacturer’s recommendations and appro- 357 NATIONAL BOARD INSPECTION CODE priate ASME Code section. To preclude unsafe and unstable valve operations or erroneous performance test results, it is recommended that low volume testing equipment (e.g., gas cylinders without a test vessel, hand pumps, tubing, etc.) should be avoided. 11. Sealing After final adjusting and acceptance by quality control inspection, all external adjustments will be sealed with a safety seal providing a means of identification of the organization performing the repair. 12. Nameplate The repairer will place a repair nameplate on each repaired valve. The nameplate shall, as a minimum, meet the requirements of RE-1061. E-3000 b. Disassemble main valve. Where lift adjustments are provided, do not remove the locking device or change the lift unless it is required as part of conversion. c. Remove the nozzle if recommended by the manufacturer’s maintenance instructions and/or when required as part of conversion. 3. Cleaning a. Pilot – Components of pilot are small and must be handled carefully to prevent damage or loss. Clean parts and nameplates with solvents which will not affect the parent metal and/or polish with 500 grit paper. b. Main Valve – Clean by appropriate means such as abrasive blast. Finishes of machined surfaces must not be affected. (Caution: Do not use a cleaning method that will damage the parts or nameplates.) PILOT OPERATED SAFETY RELIEF VALVES 1. Visual Inspection as Received This information is to be recorded: a. Complete nameplate data, plus any other important information received from the customer. 4. Inspection a. Pilot b. User identification number, if applicable. c. Seals on external adjustment (yes/ no). d. Identification on seal. e. Obvious damage and external condition including missing or misapplied parts. 2. Disassembly a. Remove pilot and disassemble per manufacturer’s maintenance instruction. 358 1. Check spring for damage such as corrosion, cracks, out of square ends, etc. 2. Inspect all parts for damage. Small burrs or scratches may be removed by polishing. Severely damaged parts should be replaced. (Internal components or pilots should not be repaired by machining as the functions of the pilot could easily be impaired.) 3. Check strainers on inlet and outlet lines. 4. Replace all soft goods per manufacturer’s recommendation. APPENDIX E — RECOMMENDED PROCEDURES FOR REPAIRING PRESSURE RELIEF VALVES b. Main Valve 1. Check nozzle seating surface for nicks. These can be removed by machining or lapping as required. 2. Check the piston and liner (or other moving member) for galling or excessive wear. The piston should move freely in the liner. 3. Replace soft goods or relap disk as required. 4. Where lift adjustments are provided, measure the lift per the manufacturer’s specifications. 5. Testing All test data is to be recorded. Testing will be done in accordance with the manufacturer’s recommendation and in accordance with the applicable ASME Code section. To preclude unsafe and unstable valve operations or erroneous performance test results, it is recommended that low volume testing equipment (e.g., gas cylinders without a test vessel, hand pumps, tubing, etc.) should be avoided. 6. Sealing After final adjustment and acceptance by quality control, all external adjustments will be sealed by means assuring positive identification of the organization performing the repair. 7. Nameplate The repairer will place a repair nameplate on each repaired valve. The nameplate, as a minimum, shall meet the requirements of RE-1061. 359 NATIONAL BOARD INSPECTION CODE 360 Pressure Differential Between Safety or Safety Relief Valve Setting and Boiler or Pressure Vessel Operating Pressure Appendix F 361 NATIONAL BOARD INSPECTION CODE APPENDIX F — PRESSURE DIFFERENTIAL BETWEEN SAFETY OR SAFETY RELIEF VALVE SETTING AND BOILER OR PRESSURE VESSEL OPERATING PRESSURE F-1000 If a safety valve or safety relief valve is subjected to pressure at or near its set pressure, it will tend to weep or simmer, and deposits may accumulate in the seat and disk area. Eventually, this can cause the valve to freeze close and thereafter the valve could fail to open at the set pressure. Unless the source of pressure to the boiler or pressure vessel is interrupted, the pressure could exceed the rupture pressure of the vessel. It is important that the pressure differential between the valve set pressure and the boiler or pressure vessel operating pressure is sufficiently large to prevent the valve from weeping or simmering. F-2000 KPa), the boiler operating pressure should not exceed 75 psi (520 KPa). SCOPE HOT WATER HEATING BOILERS For hot water heating boilers, the recommended pressure differential between the pressure relief valve set pressure and the boiler operating pressure should be at least 10 psi (70 KPa), or 25% of the boiler operating pressure, whichever is greater. Two examples follow: a. If the safety relief valve of a hot-waterheating boiler is set to open at 30 psi (210 KPa), the boiler operating pressure should not exceed 20 psi (140 KPa). b. If the safety relief valve of a hot water heating boiler is set to open at 100 psi (690 Section IV of the ASME Code does not require that safety relief valves used on hot water heating boilers have a specified blowdown. Therefore, to help ensure that the safety relief valve will close tightly after opening and when the boiler pressure is reduced to the normal operating pressure, the pressure at which the valve closes should be well above the operating pressure of the boiler. F-3000 STEAM HEATING BOILERS For steam heating boilers, the recommended pressure differential between the safety valve set pressure and boiler operating pressure should be at least 5 psi (35 KPa), i.e., the boiler operating pressure should not exceed 10 psi (70 KPa). Since some absorption-type refrigeration systems use the steam heating boiler for their operation, the boiler operating pressure may exceed 10 psi (70 KPa). If, the boiler operating pressure is greater than 10 psi (70 KPa), it should not exceed 15 psi (100 KPa), minus the blowdown pressure of the safety valve. This recommendation can be verified by increasing the steam pressure in the boiler until the safety valve pops, then slowly reducing the pressure until it closes, to ensure that this closing pressure is above the operating pressure. 362 APPENDIX F — PRESSURE DIFFERENTIAL BETWEEN SAFETY OR SAFETY RELIEF VALVE SETTING AND BOILER OR PRESSURE VESSEL OPERATING PRESSURE F-4000 POWER BOILERS For power boilers (steam), the recommended pressure differentials between the safety valve set pressure and the boiler operating pressure are as follows: MINIMUM PRESSURE DIFFERENTIAL AS PERCENTAGE OF BOILER DESIGN PRESSURE DESIGN PRESSURE: over 15 psi to 300 psi 10% but not less than 7 psi (100 KPa to 2100 KPa) (50 KPa) over 300 psi to 1000 psi 7% but not less than 30 psi (2100 KPa to 6900 KPa) (210 KPa) over 1000 psi to 2000 psi 5% but not less than 70 psi (6900 KPa to 13.8 MPa) (500 KPa) over 2000 psi per designer’s judgement (13.8 MPa) Notes: 1. Above 2000 psi (13.8 MPa) the pressure differential between operating pressure and the maximum allowable working pressure is a matter for the designer’s judgement, taking into consideration such factors as satisfactory operating experience and the intended service conditions . 2. Safety relief valves in hot water service are more susceptible to damage and subsequent leakage, than safety valves relieving steam. It is recommended that the maximum allowable working pressure of the boiler and safety relief valve setting for high-temperature hot water boilers be selected substantially higher than the desired operating pressure, so as to minimize the times the safety relief valve must lift. F-5000 PRESSURE VESSELS Due to the variety of service conditions and the various designs of pressure relief valves, only general guidelines can be given regarding differentials between the set pressure of the valve and the operating pressure of the vessel. Operating difficulty will be minimized by providing an adequate differential for the application. The following is general advisory information on the characteristics of the intended service and of the pressure relief valves which may bear on the proper pressure differential selection for a given application. These considerations should be reviewed early in the system design since they may dictate the maximum allowable working pressure of the system. To minimize operational problems it is imperative that the user consider not only normal operating conditions of the fluids (liquids or gases), pressures, and temperatures but also start-up and shutdown conditions, process upsets, anticipated ambient conditions, instrument response time, pressure surges due to quick-closing valves, etc. When such conditions are not considered, the pressure relief devices may become, in effect, a 363 NATIONAL BOARD INSPECTION CODE pressure controller, a duty for which it was not designed. Additional consideration should be given to the hazard and pollution associated with the release of the fluid. Larger differentials may be appropriate for fluids which are toxic, corrosive, or exceptionally valuable. The blowdown characteristics and capability are the first consideration in selecting a compatible valve and operating margin. After a self-actuated release of pressure, the valve must be capable of reclosing above the normal operating pressure. For example: if the valve is set at 100 psi (690 KPa) with a 7% blowdown, it will close at 93 psi (640 KPa). The operating pressure must be maintained below 93 psi (640 KPa) in order to prevent leakage or flow from a partially open valve. Users should exercise caution regarding the blowdown adjustment of large, spring-loaded valves. Test facilities, whether owned by the manufacturer, repair house, or user, may not have sufficient capacity to accurately verify the blowdown setting. The setting cannot be considered accurate unless made in the field on an actual installation. Pilot operated valves represent a special case from the standpoint of both blowdown and tightness. The pilot portion of some pilot operated valves can be set at blowdowns as short as 2%. This characteristic is not, however, reflected in the operation of the main valve in all cases. The main valve can vary considerably from the pilot depending on the location of the two components in the system. If the pilot is installed remotely from the main valve, significant time and pressure lags can occur, but reseating of the pilot assures reseating of the main valve. The pressure drop in connecting piping between the pilot and the main valve must not be excessive, otherwise the operation of the main valve will be adversely affected. are specified and also on such factors as corrosion and temperature. The required tightness and test method should be specified to comply at a pressure not lower than the normal operating pressure of the process. It should be remembered that any degree of tightness obtained should not be considered permanent. Service operation of a valve almost invariably reduces the degree of tightness. The following minimum pressure differentials are recommended unless the safety or safety relief valve has been designed or tested in a specific or similar service and a smaller differential has been recommended by the manufacturer: a. for set pressures up to 70 psi (480 KPa), the recommended pressure differential is 5 psi (35 KPa); b. for set pressure between 70 and 1000 psi (480 KPa and 6900 KPa), the recommended pressure differential is 10% of set pressure; c. for set pressures above 1000 psi (6900 KPa), the recommended pressure differential is 7% of set pressure. Tightness capability is another factor affecting valve selection, whether spring-loaded or pilot operated. Tightness varies somewhat depending on whether metal or resilient seats 364 Safety Valves on the Low-Pressure Side of Steam Pressure-Reducing Valves Appendix G 365 NATIONAL BOARD INSPECTION CODE APPENDIX G — SAFETY VALVES ON THE LOW-PRESSURE SIDE OF STEAM PRESSURE-REDUCING VALVES G-1000 SCOPE The subject of protection of vessels in steam service connected to the low pressure side of a steam pressure-reducing valve is of considerable importance to proper operation of auxiliary equipment such as pressure cookers, hot water heating systems, etc., operating at pressures below that which the primary boiler generating unit is operating. To automatically reduce the primary boiler pressure for such processing equipment, pressure-reducing valves are used. The manufacturers of such equipment have data available listing the volume of flow through reducing valves manufactured by them, but such data are not compiled in a form that the results can be deduced readily. To protect the equipment operating on the low pressure side of a pressure-reducing valve, safety valves of a relieving capacity sufficient to prevent an unsafe pressure rise in case of failure of the pressure-reducing valve, should be installed. The pressure-reducing valve is a throttling device, the design of which is based on certain diaphragm pressures opposed by spring pressure which, in turn, controls the opening through the valve. If the spring, the diaphragm, or any part of the pressure-reducing valve fails, steam will flow directly through the valve and the low pressure equipment will be subjected to the boiler pressure. To protect the equipment operating on the low pressure side of the pressure-reducing valve, safety valve(s) should be installed on the low pressure side of the pressure-reducing valve which will provide a relieving capacity sufficient to prevent the pressure from rising above the system design pressure. In most cases pressure-reducing valves used for the reduction of steam pressures have the same pipe size on the inlet and outlet. In case of failure of a pressure-reducing valve, the safety valve on the low pressure side must have a capacity to take care of the volume of steam determined by the high pressure side and the area of the pipe. G-2000 INSTALLATION OF SAFETY VALVES In most cases it is necessary to install more than one safety valve on the low pressure side of the pressure-reducing valve. It is advisable, if the safety valves are connected to the pipe attached to the pressure-reducing valve, that each safety valve have a separate connection to the pipe. It is not important that all the safety valves be mounted on the pipeline connecting the pressure-reducing valve to the auxiliaries. Safety valves will be equally effective if they are attached to some of the auxiliaries provided the piping between the pressure-reducing valve and the safety valve is of a size adequate for the maximum pressure, and there are no intervening stop valves. G-3000 SAFETY VALVE CAPACITY The capacity of the safety valve(s) on the low pressure side of the pressure-reducing valve should be based on the capacity of the pressure-reducing valve when wide open or under maximum flow conditions or the flow capacity through the bypass valve. By using the formula in G-4000 below, Inspectors may calculate the required relieving capacities of the safety valve(s) installed on the low pressure side of the pressure-reducing valve. Usually a pressure-reducing valve has a bypass arrangement so that in case of failure of the pressure-reducing valve the boiler pres- 366 APPENDIX G — SAFETY VALVES ON THE LOW-PRESSURE SIDE OF STEAM PRESSURE REDUCING VALVES sure may be short circuited into the low pressure line without passing through the pressure-reducing valve. When determining the required relieving capacity of safety valves for the low pressure side of the pressure-reducing valve, the steam flow through the bypass must be taken into consideration. G-4000 CALCULATION OF SAFETY VALVE RELIEVING CAPACITY When a pressure-reducing valve is installed, there are two possibilities of introducing boiler pressure into the low pressure system: a. the failure of the pressure-reducing valve so that it remains wide open; K1 = flow coefficient for the bypass valves (see V) C1 = flow of saturated steam through a 1 sq. in. pipe at various pressure differentials from Table G-4000. G-5000 It is possible that the flow coefficients K and K1 may not be known and in such instances for approximating the flow, a factor of 1/3 may be substituted for K and 1/2 for K1. The formulas in G-4000 then become: W = 1/3 AC for the capacity through the pressure-reducing valve and W = 1/2 A1 C1 for the capacity through the bypass valve. b. the possibility of the bypass valve being open. It is necessary therefore, to determine the flow under both circumstances (a) and (b) and check that the size of the safety valve under either condition will be adequate. The following formula should be used: a. steam flow, W in lbs/hr through the pressure-reducing valve W = AKC where, A = internal area in sq. in. of the inlet pipe size of the pressure-reducing valve (ref. Table 2) K = flow coefficient for the pressure reducing valve (see G-5000) C = flow of saturated steam through a 1 sq. in. pipe at various pressure differentials from Table G-4000. b. steam flow, W in lbs/hr through the bypass valve W = A1 K1 C1 where, A1 = internal area in sq. in. of the pipe size of the bypass around the pressurereducing valve STEAM FLOW WHEN FLOW COEFFICIENTS ARE NOT KNOWN Caution should be exercised when substituting these factors for the actual coefficients since this method will provide approximate values only and the capacities so obtained may in fact be lower than actual. It is recommended that the actual flow coefficient be obtained from the pressure-reducing valve manufacturer and reference books be consulted for the flow coefficient of the bypass valve. G-6000 TWO-STAGE PRESSUREREDUCING VALVE STATIONS The safety relief valve for two-stage pressurereducing valve stations shall be sized on the basis of the high side pressure and the inlet size of the first pressure-reducing valve in the line. If an intermediate pressure line is taken off between the pressure-reducing valves then this line and the final low side shall be protected by safety relief valves sized on the basis of the high side pressure and the inlet size of the first pressure-reducing valve. See Table G-6000. 367 NATIONAL BOARD INSPECTION CODE TABLE G-4000 — Capacity of Saturated Steam, in lb./hr., per sq. in. of Pipe Area Outlet pres., psi 1000 950 900 850 800 750 700 650 600 550 500 450 400 350 300 250 200 175 150 125 110 100 85 75 60 50 40 30 25 15 10 5 Pressure reducing valve inlet pressure, psi 1500 1450 1400 1350 1300 1250 1200 1150 1100 1050 1000 950 900 76560 77430 77750 77830 ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... 72970 74180 74810 74950 75070 ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... 69170 70760 71720 72160 72330 ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... 64950 67000 68340 69130 69490 69610 ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... 60540 63100 64870 66020 66700 66880 66900 ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... 55570 58770 61040 62610 63680 64270 64270 ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... 49930 53920 56820 58900 60390 61260 61520 61550 ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... 43930 48610 52260 54930 56910 58200 58820 58860 58980 ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... 35230 42380 47050 50480 53060 54840 55870 56260 56270 ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... 25500 34890 41050 45470 48800 51170 52670 53480 53660 53810 ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... 24910 33490 39660 43980 47080 49170 50440 51020 51040 ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... 23960 29080 38340 42420 45230 47070 48470 48470 ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... 23190 31610 37110 40860 43400 45010 45800 45850 45870 ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... Where capacities are not shown for inlet and outlet conditions, use the highest capacity shown under the applicable inlet pressure column. Metric equivalents will appear in the 2005 Addendum. TABLE G-4000 — Capacity of Saturated Steam, in lb./hr., per sq. in. of Pipe Area Outlet pres., psi 1000 950 900 850 800 750 700 650 600 550 500 450 400 350 300 250 200 175 150 125 110 100 85 75 60 50 40 30 25 15 10 5 Pressure reducing valve inlet pressure, psi 850 800 750 700 650 600 550 500 450 400 350 300 250 ..... ..... ..... ..... 22550 30600 35730 39200 41500 42840 43330 43330 ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... 21800 29420 34250 37470 39850 40530 40730 40760 ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... 21020 28260 32800 35730 37610 38150 38220 ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... 20190 27090 31310 33880 35260 35680 ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... 19480 25940 29760 31980 33050 33120 33240 ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... 18620 24630 28080 29980 30690 ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... 17720 23290 26380 27910 28140 28150 ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... 16680 21870 24570 25610 25650 ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... 15760 20460 22620 23200 ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... 14790 18860 21000 21350 ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... 13630 17100 18250 18250 18250 18780 ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... 10800 15350 16000 16200 ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... 10900 12600 13400 13600 13600 13600 13600 13600 13630 ..... ..... ..... ..... ..... ..... ..... Where capacities are not shown for inlet and outlet conditions, use the highest capacity shown under the applicable inlet pressure column. Metric equivalents will appear in the 2005 Addendum. 368 APPENDIX G — SAFETY VALVES ON THE LOW-PRESSURE SIDE OF STEAM PRESSURE REDUCING VALVES TABLE G-4000 — Capacity of Saturated Steam, in lb./hr., per sq. in. of Pipe Area Outlet pres., psi 1000 950 900 850 800 750 700 650 600 550 500 450 400 350 300 250 200 175 150 125 110 100 85 75 60 50 40 30 25 15 10 5 Pressure reducing valve inlet pressure, psi 200 175 150 125 100 85 75 60 50 40 30 25 ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... 7250 9540 10800 11000 11000 11000 11000 11000 11000 11000 11050 ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... 6750 8780 9460 9760 ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... 6220 7420 7970 8480 ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... 4550 5630 6640 7050 7200 ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... 4070 4980 5750 5920 ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... 3150 4540 5000 5140 ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... 3520 4230 4630 ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... 2680 3480 3860 ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... 2470 3140 3340 ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... 2210 2580 2830 ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... 1485 2320 ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... 1800 2060 ..... Where capacities are not shown for inlet and outlet conditions, use the highest capacity shown under the applicable inlet pressure column. Metric equivalents will appear in the 2005 Addendum. TABLE G-6000 — Pipe Data Nominal pipe size, in. (DN) Actual external diameter, in. (mm) 3/8 (10) 1/2 (15) 3/4 (20) 1 (25) 1-1/4 (32) 1-1/2 (40) 2 (50) 2-1/2 (65) 3 (80) 3-1/3 (90) 4 (100) 5 (125) 6 (150) 8 (200) 10 (250) 12 (300) 0.675 (17) 0.840 (21) 1.050 (27) 1.315 (33) 1.660 (42) 1.900 (48) 2.375 (60) 2.875 (73) 3.500 (89) 4.000 (102) 4.500 (114) 5.563 (141) 6.625 (168) 8.625 (219) 10.750 (273) 12.750 (324) Approx. internal diameter, in. (mm) 0.49 (12) 0.62 (16) 0.82 (21) 1.05 (27) 1.38 (35) 1.61 (41) 2.07 (53) 2.47 (63) 3.07 (78) 3.55 (90) 4.03 (102) 5.05 (128) 6.07 (154) 8.07 (205) 10.19 (259) 12.09 (307) Approx. internal area sq. in. (sq. mm) 0.19 (123) 0.30 (194) 0.53 (342) 0.86 (555) 1.50 (968) 2.04 (1,316) 3.36 (2,168) 4.78 (3,084) 7.39 (4,768) 9.89 (6,381) 12.73 (8,213) 19.99 (12,897) 28.89 (18,639) 51.15 (33,000) 81.55 (52,613) 114.80 (74,064) Note: In applying these rules, the area of the pipe is always based upon standard weight pipe and the inlet size of the pressure reducing valve. 369 NATIONAL BOARD INSPECTION CODE 370 Recommended Guide for the Inspection of Pressure Vessels in LP Gas Service — Nonmandatory Appendix H 371 NATIONAL BOARD INSPECTION CODE APPENDIX H — RECOMMENDED GUIDE FOR THE INSPECTION OF PRESSURE VESSELS IN LP GAS SERVICE H-1000 GENERAL CONDITIONS H-3000 Pressure vessels designed for storing LP gas can be stationary or can be mounted on skids. LP gases are generally considered to be noncorrosive to the interior of the vessel. This part is provided for guidance of a general nature for the owner, user, or jurisdictional authority. There may be occasions where more detailed procedures will be required. ASSESSMENT OF INSTALLATION The application of this section to underground vessels will only be necessary when evidence of structural damage to the vessel has been observed, leakage has been determined, or the tank has been dug up and is to be reinstalled. The type of inspection given to pressure vessels should take into consideration the condition of the vessel and the environment in which it operates. The inspection may be external or internal, and use a variety of nondestructive examination methods. Where there is no reason to suspect an unsafe condition or where there are no inspection openings, internal inspections need not be performed. The external inspection may be performed when the vessel is pressurized or depressurized, but shall provide the necessary information that the essential sections of the vessel are of a condition to operate. H-2000 H-3100 PRE-INSPECTION ACTIVITIES A review of the known history of the pressure vessel should be performed. This should include a review of information, such as: a. Operating conditions DEFINITIONS Dents — Deformations caused by a blunt object coming in contact with the vessel in such a way that the thickness of the metal is not materially reduced. c. Results of any previous inspection Cuts or Gouges — Deformations caused by a sharp object coming in contact with the vessel in such a way as to cut into or upset the metal reducing the thickness of the metal at that point. d. Current jurisdictional inspection certificate, if required Corrosion or Pitting — The loss of wall thickness by corrosive media, for example: e. ASME Code symbol stamping or mark of code of construction, if required Isolated Pitting — Small diameter voids separated from other pits or corrosion that do not effectively weaken the vessel. b. Normal contents of the vessel f. National Board and/or jurisdictional registration number, if required The vessel should be sufficiently cleaned to allow for visual inspection. Line Corrosion — A loss of wall thickness (corrosion) in a continuous pattern or pitting connected in a narrow band or line. Crevice Corrosion — A loss of metal in the area of the intersection of skirts (footrings), collars (headrings), saddle bands and other attachments with the vessel. 372 APPENDIX H — RECOMMENDED GXUIDE FOR THE INSPECTION OF PRESSURE VESSELS IN LP GAS SERVICE General Corrosion — A loss of metal over a considerable surface area of the vessel. other supports should be examined for distortion or cracks at welds. Crack — Any surface or subsurface separation of base metal or weld material whose extent must be determined by nondestructive examination methods. See H-3510. d. Vessel Connections Components which are exterior to the vessel and are accessible without disassembly shall be inspected as described in this paragraph. Manholes, reinforcing plates, nozzles, or other connections shall be examined for cracks, deformation or other defects. Bolts or nuts should be examined for corrosion or defects. Weep holes in reinforcing plates shall remain open to provide visual evidence of leakage as well as to prevent pressure build up between the vessel and the reinforcing plate. Accessible flange faces should be examined for distortion. It is not intended that flanges or other connections be opened unless there is evidence of corrosion to justify opening the connection. Distortion — Any change in the original shape of the vessel, for example: Bulges — Permanent deformations caused by excessive internal pressure that results in the pressure vessel’s surface being outside its original symmetry. H-3200 EXTERNAL INSPECTION All parts of the vessel shall be inspected for corrosion, distortion, cracking or other conditions as described in this section. In addition, the following should be reviewed, where applicable: a. Insulation If the insulation is in good condition and there is no reason to suspect an unsafe condition behind it, then it is not necessary to remove the insulation in order to inspect the vessel. However, it may be advisable to remove a small portion of the insulation in order to determine its condition and the condition of the vessel surface. b. Evidence of Leakage Any leakage of vapor or liquid shall be investigated. Leakage coming from behind insulation, supports, or evidence of past leakage shall be thoroughly investigated by removing any insulation necessary until the source is established. c. Structural Attachments The pressure vessel mountings should be checked for adequate allowance for expansion and contraction, such as provided by slotted bolt holes or unobstructed saddle mountings. Attachments of legs, saddles, skirts or e. Fire Damage Pressure vessels shall be carefully inspected for evidence of fire damage. The extent of fire damage determines the repair that is necessary, if any. H-3300 INTERNAL INSPECTION When there is a reason to suspect an unsafe condition, the suspect parts of the vessel shall be inspected and evaluated. See RB-6230. H-3400 NONDESTRUCTIVE EXAMINATION (NDE) Listed below are a variety of methods that may be employed to assess the condition of the pressure vessel. These examination methods should be implemented by experienced and qualified individuals. Generally, some form of surface preparation will be required prior to the use of these examination methods: visual, magnetic particle, liquid penetrant, ultrasonic, radiography, radioscopy, eddy current, metallographic examination, and 373 NATIONAL BOARD INSPECTION CODE acoustic emission. When there is doubt as to the extent of a defect or detrimental condition found in a pressure vessel, additional NDE may be required. H-3500 ACCEPTANCE CRITERIA H-3510 CRACKS When dents are identified which exceed the limits set forth in these paragraphs, the vessel shall be removed from service until the dents are repaired by a qualified repair organization or permanently retired from service. Cracks in the pressure boundary (heads, shells, nozzles, welds joining parts, and attachment welds) are unacceptable. When a crack is identified, the vessel shall be removed from service until the crack is repaired by a qualified repair organization or permanently retired from service. See Part RC. H-3520 diameter. The maximum depth shall not exceed one twentieth of the mean dent diameter. The use of a template may be required to measure dents on heads. DENTS Dents may be evaluated as follows: a. Shells The maximum mean dent diameter in shells shall not exceed 10% of the shell diameter, and the maximum depth of the dent shall not exceed 10% of the mean dent diameter. The mean dent diameter is defined as the average of the maximum dent diameter and the minimum dent diameter. If any portion of the dent is closer to a weld than 5% of the shell diameter, the dent shall be treated as a dent in a weld area, see paragraph H3520(b). b. Welds The maximum mean dent diameter on welds (i.e., part of the deformation includes a weld) shall not exceed 10% of the shell diameter. The maximum depth shall not exceed one twentieth of the mean dent diameter. H-3530 BULGES Bulges may be evaluated as follows: a. Shells If a bulge is suspected, the circumference shall be measured at the suspect location and several places remote from the suspect location. The variation between measurements shall not exceed 1%. b. Heads If a bulge is suspected, the radius of curvature shall be measured by the use of templates. At any point the radius of curvature shall not exceed 1.25% of the diameter for the specified shape of the head. When bulges are identified which exceed the limits set forth in these paragraphs, the vessel shall be removed from service until the bulges are repaired by a qualified repair organization or permanently retired from service. H-3540 CUTS OR GOUGES When a cut or a gouge exceeds 1/4 of the thickness of the vessel, the vessel shall be removed from service until it is repaired by a qualified repair organization or permanently retired from service. c. Heads The maximum mean dent diameter on heads shall not exceed 10% of the shell 374 APPENDIX H — RECOMMENDED GXUIDE FOR THE INSPECTION OF PRESSURE VESSELS IN LP GAS SERVICE H-3550 service until repaired by a qualified repair organization or permanently retired from service. CORROSION Corrosion may be evaluated as follows: a. Line and Crevice Corrosion For line and crevice corrosion, the depth of the corrosion shall not exceed 1/4 of the original wall thickness. b. Isolated Pitting Isolated pits may be disregarded provided that: 1. Their depth is not more than one-half the required thickness of the pressure vessel wall (exclusive of corrosion allowance); H-3570 FIRE DAMAGE Fire damage may be evaluated as follows: a. Vessels in which bulging exceeds the limits of H-3530(a) or distortion which exceeds the limits of the original code of construction (e.g., Section VIII, Div. 1 of the ASME Code) shall be removed from service until repaired by a qualified organization or permanently retired from service. 2. The total area of the pits does not exceed 7 sq. in. (4500 sq. mm) within any 8 in. (200 mm) diameter circle; and b. Common evidence of exposure to fire is: 3. The sum of their dimensions along any straight line within this circle does not exceed 2 in. (50 mm). 2. burning or scarring of the metal, c. General Corrosion For a corroded area of considerable size the thickness along the most critical plane of such area may be averaged over a length not exceeding 20 in. (500 mm). The thickness at the thinnest point shall not be less than 50% of the required wall thickness and the average shall not be less than 75% of the required wall thickness. When general corrosion is identified which exceeds the limits set forth in this paragraph, the pressure vessel shall be removed from service until it is repaired by a qualified organization or permanently retired from service. 4. burning or melting of the valves. H-3560 LEAKS Leakage is unacceptable. When leaks are identified, the vessel shall be removed from 1. charring or burning of the paint or other protective coat, 3. distortion, or c. A pressure vessel which has been subjected to the action of fire shall be removed from service until it has been properly evaluated. The general intent of this requirement is to remove from service pressure vessels which have been subject to the action of fire which has changed the metallurgical structure or the strength properties of the steel. This is normally determined by visual examination as described above with particular emphasis given to the condition of the protective coating. If there is evidence that the protective coating has been burned off any portion of the pressure vessel surface, or if the pressure vessel is burned, warped, or distorted, it is assumed that the pressure vessel has been overheated. If, however, the protective coating is only smudged, discolored, or 375 NATIONAL BOARD INSPECTION CODE blistered and is found by examination to be intact underneath, the pressure vessel shall not be considered affected within the scope of this requirement. Vessels that have been involved in a fire and show no distortion shall be requalified for continued service by retesting using the hydrostatic test procedure applicable at the time of original fabrication. H-4000 RECORDS A permanent record shall be maintained for each vessel repaired by a qualified organization. The record shall include the following: a. An ASME Manufacturer’s Data Report or, if the vessel is not ASME Code stamped, other equivalent specifications. b. Form R-1 Report of Welded Repair or other equivalent document describing the extent of all repairs to the vessel. H-5000 CONCLUSIONS Any defect or deficiency in the condition, operating, and maintenance practices of the pressure vessel should be evaluated at the time of inspection and decision made for the correction of such defect or deficiency. 376 Installation Requirements Appendix I 377 NATIONAL BOARD INSPECTION CODE APPENDIX I — INSTALLATION REQUIREMENTS I-1000 INSTALLATION REQUIREMENTS I-1100 INTRODUCTION The proper installation of boilers, pressure vessels, piping and other pressure-retaining items is essential for safe and satisfactory operation. The owner-user is responsible for ensuring that installations meet all the requirements of the jurisdiction at the point of installation including licensing, registration or certification of those performing installations. The following are minimum requirements and users of this document are cautioned that it is not a substitute for sound engineering evaluations of a particular installation. Where mandated by a jurisdiction, these requirements are mandatory. Where a jurisdiction establishes different requirements or where a conflict exists, the rules of the jurisdiction prevail. I-1200 PURPOSE a. The purpose of these rules is to establish minimum requirements, which, if followed, will ensure that pressure-retaining items, when installed, may be safely operated, inspected and maintained. b. It should be recognized that many of the requirements included in these rules must be considered in the design of the pressure-retaining item by the manufacturer. However, the owneruser is responsible for ensuring that the installation complies with all the applicable requirements contained herein. Further, the installer is responsible for complying with the applicable sections when performing work on behalf of the owner-user. I-1300 APPLICATION OF THESE RULES a. As referenced in lower case letters, the terms “owner”, “user” or “owner/user” means any person, firm or corporation legally responsible for the safe operation of the boiler, pressure vessel, piping or other pressure-retaining item. Further, where the term owner is used, it shall mean the owner, or user, or the owner’s or user’s designee, except for I-1300(b). b. Where the owner is required to perform an activity, it is intended that the owner or the owner’s designee may perform the activity; however, the owner retains responsibility for compliance with these rules. c. These rules refer to documentation obtained from the jurisdiction (installation permit, operating permit). It is not intended to require the jurisdiction to issue such permits but rather a caution to owners and installers that such permits may be required. I-2000 POWER BOILERS I-2100 INTRODUCTION I-2110 SCOPE This section provides requirements for the installation of power boilers as defined in I-2120. For installation of items that do not fall within the scope of this section, refer to the following as applicable: I-3000 Heating Boilers and Potable Water Heaters I-4000 Pressure Vessels I-5000 Piping 378 APPENDIX I — INSTALLATION REQUIREMENTS I-2120 POWER BOILERS I-2220 A power boiler is a closed vessel in which water or other liquid is heated, steam or vapor generated, steam or vapor is superheated, or any combination thereof, under pressure for use external to itself, by the direct application of energy from the combustion of fuels or from electricity or solar energy. The term boiler includes fired units for heating or vaporizing liquids other than water but does not include fired process heaters and systems. The term boiler also shall include the apparatus used to generate heat and all controls and safety devices associated with such apparatus or the closed vessel. a. Power Boiler – a boiler in which steam or other vapor is generated at a pressure in excess of 15 psig (100 kPa) for use external to itself. b. High Temperature Boiler – a boiler in which water or other fluid is heated and operates at a pressure in excess of 160 psig (1.1 MPa) and/or temperature in excess of 250°F (120°C). c. Electric Boiler – a power boiler as described above in which the source of heat is electricity. I-2200 I-2210 EQUIPMENT CERTIFICATION All boilers shall have documented certification from the manufacturer indicating that the boiler complies with the requirements of the code of construction. The certification shall identify the revision level of the code of construction to which the boiler was fabricated. I-2230 JURISDICTIONAL REVIEW a. The owner shall determine jurisdictional requirements (i.e., certificates, permits, licenses, etc.) before installing the equipment. The organization responsible for installation shall obtain all permits required by the jurisdiction prior to commencing installation. b. The owner shall determine jurisdictional requirements (i.e., certificates, permits, licenses, etc.) before operating the equipment. The owner shall obtain operating certificates, permits, etc. required by the jurisdiction prior to commencing operation. I-2240 INSPECTION All boilers shall be inspected after installation and prior to commencing operation. CERTIFICATION, INSPECTION AND JURISDICTIONAL REQUIREMENTS RESPONSIBILITY The owner is responsible for satisfying jurisdictional requirements for certification and documentation. When required by jurisdictional rules applicable to the location of installation, the boiler shall not be operated until the required documentation has been provided to the owner and the jurisdiction. 379 I-2300 GENERAL REQUIREMENTS I-2310 SUPPORTS, FOUNDATIONS AND SETTINGS Each boiler and its associated piping must be safely supported. Design of supports, foundations and settings shall consider vibration, movement (including thermal movement) and loadings (including flooded conditions) in accordance with jurisdictional NATIONAL BOARD INSPECTION CODE requirements, manufacturer’s recom-mendations and/or other industry standards, as applicable. e. Boilers with a bottom opening shall have at least 12 in. (300 mm) of unobstructed clearance. I-2320 STRUCTURAL STEEL I-2340 a. If the boiler is supported by structural steel work, the steel supporting members shall be so located or insulated that the heat from the furnace will not affect their strength. BOILER ROOM REQUIREMENTS I-2341 EXIT AND EGRESS b. Structural steel shall be installed in accordance with jurisdictional requirements, manufacturer’s recommendations and/or other industry standards, as applicable. I-2330 CLEARANCES a. Boiler installations shall allow for normal operation, maintenance, and inspections. There shall be at least 36 in. (900 mm) of clearance on each side of the boiler to enable access for maintenance and/or inspection activities. Boilers operated in battery shall not be installed closer than 48 in. (1200 mm) from each other. The front or rear of any boiler shall not be located nearer than 36 in. (900 mm) from any wall or structure. Alternative clearance in accordance with the manufacturer’s recommendations are subject to acceptance by the jurisdiction. Two means of exit shall be provided for boiler rooms exceeding 500 sq. ft. (46.5 sq. m) floor area and containing one or more boilers having a fuel capacity of 1,000,000 Btu/hr. (293 W/hr.) or more (or equivalent electrical heat input). Each elevation shall be provided with at least two means of egress, each to be remotely located from the other. A platform at the top of a single boiler is not considered an elevation. I-2342 LADDERS AND RUNWAYS a. All walkways, runways, and platforms shall: 1. be of metal construction; 2. be provided between or over the top of boilers which are more than 8 ft. (2.8 m) above the operating floor to afford accessibility for normal operation, maintenance and inspection; 3. be constructed of safety treads, standard grating, or similar material and have a minimum width of 30 in. (750 mm); b. Boilers shall be installed to allow for removal and installation of tubes. c. Boilers with a top-opening manhole, shall have at least 84 in. (2100 mm) of clearance from the manhole to the ceiling of the boiler room. 4. be of bolted, welded, or riveted construction; 5. be equipped with handrails 42 in. (1050 mm) high with an intermediate rail and 4 in. (100 mm) toeboard. d. Boilers without top-opening manholes shall have at least 36 in. (90 mm) of clearance from the top of the boiler or as recommended by the manufacturer. 380 APPENDIX I — INSTALLATION REQUIREMENTS b. Stairways which serve as a means of access to walkways, runways, or platforms shall not exceed an angle of 45 degrees from the horizontal and be equipped with handrails 42 in. (1050 mm) high with an intermediate grid. c. Ladders which serve as a means of access to walkways, runways, or platforms shall: 1. be of metal construction and not less than 18 in. (450 mm) wide; 2. have rungs that extend through the side members and are permanently secured; 3. have a clearance of not less than 30 in. (750 mm) from the front of rungs to the nearest permanent object on the climbing side of the ladder; 4. have a clearance of not less than 6-1/2 in. (165 mm) from the back of rungs to the nearest permanent object; 5. have a clearance width of at least 15 in. (390 mm) from the center of the ladder on either side across the front of the ladder. d. There shall be at least two permanently installed means of egress from walkways, runways, or platforms that exceed 6 ft. (2 cm) in length. I-2343 DRAINS At least one floor drain shall be installed in the boiler room. I-2344 WATER A convenient water supply shall be provided for flushing out the boiler and its 381 appurtenances, adding water to the boiler while it is not under pressure and cleaning the boiler room floor. I-2400 SOURCE REQUIREMENTS I-2410 FEEDWATER I-2411 VOLUME The source of feedwater shall be capable of supplying a sufficient volume of water as determined by the boiler manufacturer in order to prevent damage to the boiler when all the safety relief valves are discharging at full capacity. I-2412 CONNECTION a. To prevent thermal shock, feedwater shall be introduced into a boiler in such a manner that the water will not be discharged directly against surfaces exposed to gases of high temperature or to direct radiation from the flame. b. For boiler operating pressures of 400 psi (2700 kPa) or higher, the feedwater inlet through the drum shall be fitted with shields, sleeves, or other suitable means to reduce the effects of temperature differentials in the shell or head. c. Feedwater other than condensate return shall not be introduced through the blowoff. d. Boilers having more than 500 sq. ft. (46.5 sq. m.) of water heating surface shall have at least two means of supplying feedwater. For boilers that are fired with solid fuel not in suspension, and boilers whose setting or heat source can continue to supply sufficient heat to cause damage to the boiler if the feedwater supply is interrupted, one such NATIONAL BOARD INSPECTION CODE means of supplying feedwater shall not be subject to the same interruption as the first method. Boilers fired by gaseous, liquid, or solid fuel in suspension may be equipped with a single means of supplying feedwater provided means are furnished for the immediate removal of heat input if the supply of feedwater is interrupted. e. For boilers having a water heating surface of not more than 100 sq. ft. (9 sq. m.), the feedwater piping and connection to the boiler shall not be smaller than NPS 1/2 (DN 15). For boilers having a water heating surface more than 100 sq. ft. (9 sq. m.), the feedwater piping and connection to the boiler shall not be less than NPS 3/4 (DN 20). Electric boiler feedwater connections shall not be smaller than NPS 1/2 (DN 15). f. High temperature water boilers shall be provided with means of adding water to the boiler or system while under pressure. I-2413 PUMPS Boiler feedwater pumps shall have discharge pressure in excess of the boiler rated pressure (MAWP) in order to compensate for frictional losses, entrance losses, regulating valve losses, and normal static head, etc. Each source of feedwater shall be capable of supplying feedwater to the boiler at a minimum pressure of three percent higher than the highest setting of any safety valve on the boiler plus the expected pressure drop across the boiler. The following table is a guideline for estimating feed pump differential: Boiler Pressure, psi (MPa) Boiler Feedwater Pump Discharge Pressure,* psi (MPa) 200 (1.5) 400 (3) 800 (5.5) 1,200 (8) 250 (1.7) 475 (3.3) 925 (6.4) 1,350 (9.3) *based on 34.5 lbs. (15.5 kg) of evaporation per hour @ 212°F (100°C) For forced-flow steam generators with no fixed steam or water line, each source of feedwater shall be capable of supplying feedwater to the boiler at a minimum pressure equal to the expected maximum sustained pressure at the boiler inlet corresponding to operation at maximum designed steaming capacity with maximum allowable pressure at the superheater outlet. Control devices may be installed on feedwater piping to protect the pump against overpressure. I-2414 VALVES a. The feedwater piping shall be provided with a check valve and a stop valve. The stop valve shall be located between the check valve and the boiler. b. When two or more boilers are fed from a common source, there shall also be a globe or regulating valve on the branch to each boiler located between the check valve and the feedwater source. c. When the feedwater piping is divided into branch connections and all such connections are equipped with stop and check valves, the stop and check valve in the common source may be omitted. d. On single boiler-turbine unit installations, the boiler feedwater stop valve may be located upstream from the boiler feedwater check valve. 382 APPENDIX I — INSTALLATION REQUIREMENTS e. If a boiler is equipped with duplicate feedwater supply arrangements, each such arrangement shall be equipped as required by these rules. f. A check valve shall not be a substitute for a stop valve. g. A combination feedwater stop-andcheck valve in which there is only one seat and disk and a valve stem is provided to close the valve when the stem is screwed down shall be considered only as a stop valve, a separate check valve shall be installed. h. Whenever globe valves are used on feedwater piping, the inlet shall be under the disk of the valve. i. Stop valves and check valves shall be placed on the inlet of economizers or feedwater-heating devices. j. The recirculating return line for a high temperature water boiler shall be provided with the stop valve, or valves, required for the main discharge outlet on the boiler. I-2420 or international standards and comply with the applicable local electrical codes. b. A manually operated remote shutdown switch or circuit breaker should be located just outside the boiler room door and marked for easy identification. Consideration should also be given to the type and location of the switch to safeguard against tampering. If the boiler room door is on the building exterior the switch should be located just inside the door. If there is more than one door to the boiler room, there should be a switch located at each door. 1. For atmospheric-gas burners, and oil burners where a fan is on a common shaft with the oil pump, the complete burner and controls should be shut off. 2. For power burners with detached auxiliaries, only the fuel input supply to the firebox need be shut off. c. Controls and Heat Generating Apparatus 1. Oil and gas-fired and electrically heated boilers and water heaters shall be equipped with suitable primary (flame safeguard) safety controls, safety limit switches, and burners or electric elements as required by a nationally or internationally recognized standard. FUEL Fuel systems, whether coal, oil, gas or other substance shall be installed in accordance with jurisdictional and environmental requirements, manufacturer’s recommendations and/or industry standards, as applicable. I-2430 2. The symbol of the certifying organization15 which has investigated such equipment as having complied with a nationally recognized standard shall be affixed to the equipment and shall be considered as evidence ELECTRICAL a. All wiring for controls, heat generating apparatus, and other appurtenances necessary for the operation of the boiler or boilers should be installed in accordance with the provisions of national 383 15 Organizations – A certifying organization is one that provides uniform testing, examination, and listing procedures under established, nationally recognized standards, and that is acceptable to the authorities having jurisdiction. NATIONAL BOARD INSPECTION CODE that the unit was manufactured in accordance with that standard. 3. These devices shall be installed in accordance with jurisdictional and environmental requirements, manufacturer’s recommendations and/or industry standards as applicable. I-2440 VENTILATION AND COMBUSTION AIR a. The boiler room shall have an adequate air supply to permit clean, safe combustion, minimize soot formation and maintain a minimum of 19.5% oxygen in the air of the boiler room. The combustion and ventilation air may be supplied by either an unobstructed air opening or by power ventilation or fans.16 b. Unobstructed air openings shall be sized on the basis of 1 sq. in. (650 sq. mm) free area per 2000 Btu/hr. (586 W/hr.) maximum fuel input of the combined burners located in the boiler room, or as specified in the National Fire Protection Association (NFPA) standards for oil and gas burning installations for the particular job conditions. The boiler room air supply openings shall be kept clear at all times. c. Power ventilators or fans shall be sized on the basis of 0.2 cfm (0.0057 cu meters per minute) for each 1000 Btu/hr. (293 W/hr.) of maximum fuel input for the combined burners of all boilers and water heaters located in the boiler room. 16 d. When power ventilators or fans are used to supply combustion air they shall be installed with interlock devices so that the burners will not operate without an adequate number of ventilators/fans in operation. e. The size of openings specified in I2440(b) may be reduced when special engineered air supply systems approved by the jurisdiction are used. I-2450 LIGHTING The boiler room should be well lighted and it should have an emergency light source for use in case of power failure. I-2460 EMERGENCY VALVES AND CONTROLS All emergency shut-off valves and controls shall be accessible from a floor, platform, walkway or runway. Accessibility shall mean within a 6 ft. (2 m) elevation of the standing space and not more than 12 in. (300 mm) horizontally from the standing space edge. I-2500 DISCHARGE REQUIREMENTS I-2510 CHIMNEY OR STACK Chimneys or stacks shall be installed in accordance with jurisdictional and environmental requirements, manufacturer’s recommendations and/or industry standards, as applicable. Fans – When combustion air is supplied to the boiler by an independent duct, with or without the employment of power ventilators or fans, the duct shall be sized and installed in accordance with the manufacturer ’s recommendations. However, ventilation for the boiler room must still be considered. 384 APPENDIX I — INSTALLATION REQUIREMENTS I-2520 ASH REMOVAL Ash removal systems shall be installed in accordance with jurisdictional and environmental requirements, manufacturer’s recommendations and/or industry standards, as applicable. I-2530 DRAINS I-2531 CONNECTION a. Each boiler shall have at least one drain pipe fitted with a stop valve at the lowest point of the boiler. If the connection is not intended for blowoff purposes, a single valve is acceptable if it can be locked in the closed position or a blank flange can be installed downstream of the valve. If the connection is intended for blowoff purposes, requirements of I-2650 shall be followed. b. For high temperature water boilers, the minimum size of the drain pipe shall be NPS 1 (DN 25). c. Drain pipes, valves and fittings within the same drain line shall be the same size. d. The discharge from the drain shall be piped to a safe location. I-2532 PRESSURE RATING a. When the maximum allowable working pressure of the boiler is equal to or less than 100 psi (700 kPa), the drain pipe, valve and fittings shall be rated for at least 100 psi (700 kPa) and 220°F (105°C). b. When the maximum allowable working pressure of the boiler exceeds 100 psi (700 kPa), the drain pipe, valve and 385 fittings shall be rated for at least the maximum allowable working pressure and temperature of the boiler. I-2533 PARTS a. When parts (economizers, etc.) are installed with a stop valve between the part and the boiler or the part cannot be completely drained through the drain on the boiler, a separate drain shall be installed on each such part. These drains shall meet the requirements of this paragraph. b. Each water column shall have a drain pipe fitted with a stop valve at the lowest point of the water column. The stop valve shall have the capability of being locked in the closed position while the boiler is under pressure. The minimum size of the drain shall be NPS 3/4 (DN 20) and all other requirements of this paragraph shall be met. I-2600 OPERATING SYSTEMS I-2610 BREECHING AND DAMPERS Breeching and dampers shall be installed in accordance with jurisdictional and environmental requirements, manufacturer’s recommendations and/or industry standards, as applicable. I-2620 BURNERS AND STOKERS Burners and stokers shall be installed in accordance with jurisdictional and environmental requirements, manufacturer’s recommendations and/or industry standards, as applicable. NATIONAL BOARD INSPECTION CODE I-2630 STEAM SUPPLY a. Provisions shall be made for the expansion and contraction of steam mains connected to boiler(s) so that there shall be no undue strain transmitted to the boiler(s). Steam reservoirs shall be installed on steam mains when heavy pulsations of the steam currents cause vibration of the boiler shell plates. b. Each discharge outlet of the boiler drum or superheater outlet, shall be fitted with a stop valve located at an accessible point in the steam-delivery line and as near the boiler nozzle as is convenient and practicable. The valve shall be equipped to indicate from a distance whether it is closed or open, and shall be equipped with a slow-opening mechanism. When such outlets are over NPS 2 (DN 50), the valve or valves used on the connection shall be of the outside-screw-and-yoke-rising-spindle type, so as to indicate from a distance by the position of its spindle whether it is closed or open, and the wheel may be carried either on the yoke or attached to the spindle. In the case of a single boiler and prime mover installation, the stop valve may be omitted provided the prime mover throttle valve is equipped with an indicator to show whether the valve is open or closed and is designed to withstand the required hydrostatic test pressure of the boiler. c. Stop valves and fittings shall comply with the appropriate national standard except that austenitic stainless steel is not permitted for water wetted service. d. Stop valves and fittings shall be rated for the maximum allowable working pressure of the boiler and shall be at least rated for 100 psi (700 kPa) at the expected steam temperature at the valve or fitting, in accordance with the appropriate national standard. e. The nearest stop valve or valves to the superheater outlet shall have a pressure rating at least equal to the minimum set pressure of any safety valve on the superheater and at the expected superheated steam temperature; or at least equal to 85% of the lowest set pressure of any safety valve on the boiler drum at the expected steam temperature of the superheater outlet, whichever is greater. f. Ample provision for gravity drain shall be provided when a stop valve is so located that water or condensation may accumulate. The gravity drain(s) shall be located such that the entire steam supply system can be drained. g. When boilers are connected to a common header, the connection from each boiler having a manhole opening shall be fitted with two stop valves having an ample freeblow drain between them. The discharge of this drain shall be visible to the operator while operating the valve. The stop valves shall consist of one stop check valve (set next to the boiler) and a second valve of the outside-screw-and-yoke type; or two valves of the outside-screw-and-yoke type. h. The second steam stop valve shall have a pressure rating at least equal to that required for the expected steam temperature and pressure at the valve, or the pressure rating shall be not less than 85% of the lowest set pressure of any safety valve on the boiler drum and for the expected temperature of the steam at the valve, whichever is greater. i. 386 Pressure-reducing valves may be installed in the steam supply piping downstream from the required stop valve or valves. APPENDIX I — INSTALLATION REQUIREMENTS I-2640 CONDENSATE AND RETURN Each condensate return pump where practicable, shall be provided with an automatic water level control set to maintain an adequate water level. Condensate tanks shall be vented to the atmosphere. I-2650 e. The blowoff valve or valves and the pipe and fittings between them and the boiler shall be of the same size. The minimum size of pipe and fittings shall be NPS 1 (DN 25), except boilers with 100 sq. ft. (9 sq. m.) of heating surface or less may be NPS 3/4 (DN 20). The maximum size of pipe and fittings shall not exceed NPS 2-1/2 (DN 65). For electric boilers, the minimum size of blowoff pipes and fittings shall be NPS 1 (DN 25), except for boilers of 100 kW input or less the minimum size may be NPS 3/4 (DN 20). BLOWOFF a. Except for forced-flow steam generators with no fixed steam or water line, each boiler shall have a blowoff pipe, fitted with a stop valve, in direct connection with the lowest water space practicable. When the maximum allowable working pressure of the boiler exceeds 100 psi (700 kPa) there shall be two valves installed. The blowoff piping for each electric boiler pressure vessel having a nominal water content not exceeding 100 gal. (380 l) is required to extend through only one valve. b. One of the blowoff valves shall be a slow-opening valve. When a second valve is required, the second valve may be a quick-opening or slow-opening valve. c. Two independent slow-opening valves or a slow-opening valve and quickopening valve may be combined in one body and may be used provided the combined fitting is the equivalent of two independent slow-opening valves or a slow-opening valve and a quick-opening valve, and provided further that the failure of one to operate cannot affect the operation of the other. d. Straight-run globe valves or valves where dams or pockets can exist for the collection of sediment shall not be used. 387 f. Fittings and valves shall comply with the appropriate national standard except that austenitic stainless steel and malleable iron are not permitted. g. When the maximum allowable working pressure exceeds 100 psi (700 kPa), blowoff piping shall be at least Schedule 80 and the required valves and fittings shall be rated for at least 1.25 times the maximum allowable working pressure of the boiler. When the maximum allowable working pressure exceeds 900 psi (6 MPa), blowoff piping shall be at least Schedule 80 and the required valves and fittings shall be rated for at least the maximum allowable working pressure of the boiler plus 225 psi (1.6 MPa). h. All blowoff piping, when exposed to furnace heat, shall be protected by fire brick or other heat resisting material so constructed that the piping may be readily inspected. i. On a boiler having multiple blowoff pipes, a single master stop valve may be placed on the common blowoff pipe from the boiler and one stop valve on each individual blowoff. Either the master valve or the valves on the individual blowoff lines shall be of the slow-opening type. NATIONAL BOARD INSPECTION CODE j. The discharge of blowoff pipes shall be located so as to prevent injury to personnel. k. All waterwalls or water screens that do not drain back into the boiler and integral economizers forming part of a boiler shall be equipped with blowoff piping and valves conforming to the requirements of this paragraph. l. I-2700 CONTROLS AND GAGES I-2710 WATER a. Each automatically steam-fired boiler shall be equipped with at least two lowwater fuel cutoffs. The water inlet shall not feed water into the boiler through a float chamber. Blowoff piping from a boiler may not discharge directly into a sewer. A blowoff tank, constructed to the provisions of a code of construction acceptable to the jurisdiction, shall be used where conditions do not provide an adequate and safe open discharge. Each electric steam boiler of the resistance element type shall be equipped with an automatic low-water cut-off on each boiler pressure vessel, so located as to automatically cut off the power supply to the heating elements before the surface of the water falls below the visible part of the glass. No low-water cut-off is required for electrode type boilers. m. Galvanized pipe shall not be used. n. Boiler blowoff systems shall be constructed in accordance with the Guide for Blowoff Vessels. o. Where necessary to install a blowoff tank underground, it shall be enclosed in a concrete or brick pit with a removable cover so that inspection of the entire shell and heads of the tank can be made. Piping connections used primarily for continuous operation, such as deconcentrators on continuous blowdown systems, are not classed as blowoffs but the pipe connections and all fittings up to and including the first shutoff valve shall be equal at least to the pressure requirements for the lowest set pressure of any safety valve on the boiler drum and with the corresponding saturated-steam temperature. Further, such connections shall not exceed NPS 2-1/2 (DN 65). b. Designs embodying a float and float bowl shall have a vertical straightaway drainpipe at the lowest point in the water equalizing pipe connections by which the bowl and the equalizing pipe can be flushed and the device tested. c. The water column shall be directly connected to the boiler. Outlet connections (except for damper regulator, feedwater regulator, low-water fuel cutoff, drains, steam gages, or such apparatus that does not permit the escape of an appreciable amount of steam or water) may not be placed on the piping that connects the water column to the boiler. d. Straight-run globe valves of the ordinary type shall not be used on piping that connects the water column to the boiler. Where water columns are seven feet or more above the floor level, adequate means for operating gage cocks or blowing out the water glass shall be provided. 388 APPENDIX I — INSTALLATION REQUIREMENTS e. When automatic shutoff valves are used on piping that connects the water column to the boiler, they shall conform to the requirements of the code of construction for the boiler. f. When shutoff valves are used on the connections to a water column, they shall be either outside-screw-and-yoke or lever-lifting-type gate valves or stop cocks with levers permanently fastened thereto and marked in line with their passage, or of such other through-flow constructions to prevent stoppage by deposits of sediment and to indicate by the position of the operating mechanism whether they are in open or closed position; and such valves or cocks shall be locked or sealed open. g. Each steam boiler having a fixed waterline shall have at least one water-gage glass except that boilers operated at pressures over 400 psi (3 MPa) shall be provided with two water gage glasses which may be connected to a single water column or connected directly to the drum. The gage glass connections and pipe connection shall be not less than NPS 1/2 (DN 15). Each water-gage glass shall be equipped with a valved drain. Electric steam boilers shall have at least one water gage glass. On electrode type electric boilers the gage glass shall be located as to indicate the water levels both at startup and maximum steam load conditions, as established by the boiler manufacturer. On resistance element type electric steam boilers the lowest visible part of the gage glass shall be located at least 1 in. (25 mm) above the lowest permissible water level established by the manufacturer. h. The lowest visible part of the water-gage glass shall be at least 2 in. (50 mm) above the lowest permissible water level which 389 shall be that level at which there will be no danger of overheating any part of the boiler when in operation. i. For all installations where the watergage glass or glasses are more than thirty feet (9 m.) from the boiler operating floor, it is recommended that water level indicating or recording gages be installed at eye height from the operating floor. j. Boilers of the horizontal firetube type shall be so set that when the water is at the lowest reading in the water-gage glass there shall be at least 3 in. (75 mm) of water over the highest point of the tubes, flues or crown sheet. k. Each water-gage glass shall be equipped with a top and a bottom shutoff valve of such through-flow construction as to prevent blockage by deposits of sediment and to indicate by the position of the operating mechanism whether they are in the open or closed position. The pressure-temperature rating shall be at least equal to that of the lowest set pressure of any safety valve on the boiler drum and the corresponding saturated steam temperature. I-2720 PRESSURE I-2721 GAGE REQUIREMENTS a. Each steam boiler shall have a pressure gage connected to the steam space or to the steam connection to the water column. When a pressure reducing valve is installed in the steam supply piping, a pressure gage shall be installed on the low pressure side of the pressure-reducing valve. NATIONAL BOARD INSPECTION CODE b. The dial range shall not be less than 1.5 times the pressure at which the lowest safety relief valve is set. c. The dial range should be no greater than two times the pressure at which the lowest safety relief valve is set. I-2722 CONNECTION a. For a steam boiler the gage or connection shall contain a syphon or equivalent device which will develop and maintain a water seal that will prevent steam from entering the gage tube. A valve or cock shall be placed in the gage connection adjacent to the gage. An additional valve or cock may be located near the boiler providing it is locked or sealed in the open position. No other shut-off valves shall be located between the gage and the boiler. b. Pressure gage connections shall be suitable for the maximum allowable working pressure and temperature, but if the temperature exceeds 406°F (208°C) brass or copper pipe or tubing shall not be used. The connections to the boiler, except for the syphon, if used, shall not be less than NPS 1/4 (DN 8). Where steel or wrought iron pipe or tubing is used, it shall not be less than 1/2 in. (13 mm inside diameter. The minimum size of a syphon, if used, shall be 1/4 in. (6 mm) inside diameter. I-2730 TEMPERATURE Each high temperature water boiler shall have a temperature gage or other reporting device located to provide an accurate representation of the temperature at or near the boiler outlet. I-2800 PRESSURE RELIEF VALVES I-2810 VALVE REQUIREMENTS a. Safety valves are designed to relieve steam. b. Safety relief valves are valves designed to relieve either steam or water, depending on the application. c. Safety and safety relief valves are to be manufactured in accordance with a national or international standard. d. Deadweight or weighted-lever pressure relieving valves shall not be used. e. For high temperature water boilers, safety relief valves shall have a closed bonnet, and safety relief valve bodies shall not be constructed of cast iron. f. Safety and safety relief valves with an inlet connection greater than NPS 3 (DN 80) used for pressure greater than 15 psig (100 kPa), shall have a flange inlet connection or a welding-end inlet connection. The dimensions of flanges subjected to boiler pressure shall conform to the applicable standards. g. When a safety or safety relief valve is exposed to outdoor elements which may affect operation of the valve, it is permissible to shield the valve with a cover. The cover shall be properly vented and arranged to permit servicing and normal operation of the valve. I-2820 NUMBER At least one National Board capacity certified safety or safety relief valve shall be installed on the boiler. If the boiler has more 390 APPENDIX I — INSTALLATION REQUIREMENTS than 500 sq. ft. (46 sq. m.) of heating surface, or if an electric boiler has a power input of more than 1,100 kw, two or more National Board capacity certified safety or safety relief valves shall be installed. I-2830 LOCATION a. Safety or safety relief valves shall be placed on, or as close as physically possible, to the boiler proper. b. Safety or safety relief valves shall not be placed on the feedline. c. Safety or safety relief valves shall be connected to the boiler independent of any other connection without any unnecessary intervening pipe or fittings. Such intervening pipe or fittings shall not be longer than the face-to-face dimension of the corresponding tee fitting of the same diameter and pressure rating as listed in the applicable standards. TABLE I-2840-1 — Minimum Pounds of Steam per Hour per Square Foot of Heating Surface (kg/hr/sq cm) Boiler heating surface Hand-fired Stoker-fired Oil-, gas- or pulverized-fuel-fired Firetube Boiler Watertube Boilers 5 (2112) 7 (2956) 8 (3378) 6 (2543) 8 (3378) 10 (4223) Waterwall heating surface Hand-fired Stoker-Fired Oil-, gas- or pulverized-fuel-fired 8 (3378) 10 (4223) 14 (5912) 8 (3378) 12 (5068) 16 (6756) Copper finned water tubes Hand-fired Stoker-Fired Oil-, gas- or pulverized-fuel-fired 4 (1689) 5 (2112) 5 (2112) 4 (1689) 5 (2112) 6 (2534) NOTES: When a boiler is fired only by a gas having a heat value not in excess of 200 Btu/cu. ft. (7.5 J/cu. cm.), the minimum relieving capacity may be based on the values given for hand-fired boilers above. For firetube boiler units exceeding 8000 Btu/sq. ft. (9120 J/sq. cm.) (total Fuel Btu (J) Input divided by total heating surface), the factor from the table will be increased by 1 (422.3) for every 1000 Btu/sq. ft. (1140 J/ sq. cm.) above 8000 (9120 J/sq. cm.). For units less than 7000 Btu/sq. ft. (7980 J/sq. cm.), the factor from the table will be decreased by 1 (422.3) for every 1000 Btu/sq. ft. (1140 J/sq. cm.) below 7000 (7980 J/sq. cm.). For watertube boiler units exceeding 16000 Btu/sq. ft. (18240 J/sq. cm.) (total fuel Btu input divided by the total heating surface), the factor fromthe table will be incresed by 1 (422.3) for every 1000 Btu/sq. ft. (1140 J/sq. cm.) above 16000 (18240 J/sq. cm.). For units with less than 15000 Btu/sq. ft. (17100 J/sq. cm.), the factor in the table will be decreased by 1 (422.3) for every 1000 Btu/sq. ft. (1140 J/sq. cm.) below 15000 (17100 J/sq. cm.). The heating surface shall be compued for that side of the boiler surface exposed to the products of combustion, exclusive of the superheating surface. In computing the heating surface for this purpose, only the tubes, fireboxes, shells, tube sheets, and the projected area of headers need to be considered, except that for vertical firetube steam boilers, only that portion of the tube surface up to the middle gage cock is to be computed. 391 NATIONAL BOARD INSPECTION CODE I-2840 This method should not be used on a boiler with a superheater or reheater or on a high temperature water boiler. CAPACITY a. The pressure-relieving valve capacity for each boiler shall be such that the valve or valves will discharge all the steam that can be generated by the boiler without allowing the pressure to rise more than 6% above the highest pressure at which any valve is set and in no case to more than 6% above the maximum allowable working pressure of the boiler. b. The minimum relieving capacity for other than electric boilers and forced-flow steam generators with no fixed steam line and waterline, shall be estimated for the boiler and waterwall heating surfaces as given in Table I-2840-1, but in no case may the minimum relieving capacity be less than the maximum designed steaming capacity as determined by the manufacturer. c. The required relieving capacity in pounds per hour of the safety or safety relief valves on a high temperature water boiler shall be determined by dividing the maximum output in Btu at the boiler nozzle obtained by the firing of any fuel for which the unit is designed by one thousand. d. The minimum safety or safety relief valve relieving capacity for electric boilers is 3.5 lbs./hr./kW. (1.6 kg./hr./kW.) input. e. If the safety or safety relief valve capacity cannot be computed, or if it is desirable to prove the computations, it may be checked by any one of the following methods; and if found insufficient, additional relieving capacity shall be provided: 1. By performing an accumulation test, that is, by shutting off all other steam discharge outlets from the boiler and forcing the fires to the maximum. 2. By measuring the maximum amount of fuel that can be burned and computing the corresponding evaporative capacity upon the basis of the heating value of the fuel. 3. By determining the maximum evaporative capacity by measuring the feedwater. The sum of the safety valve capacities marked on the valves shall be equal to or greater than the maximum evaporative capacity of the boiler. This method may not be used on high temperature water boilers. I-2850 SET PRESSURE One or more safety or safety relief valves on the boiler proper shall be set at or below the maximum allowable working pressure. If additional valves are used, the highest pressure setting shall not exceed the maximum allowable working pressure by more than 3%. The complete range of pressure settings of all the safety relief valves on a boiler shall not exceed 10% of the highest pressure to which any valve is set. Pressure setting of safety relief valves on high temperature water boilers may exceed this 10% range. I-2860 FORCED-FLOW STEAM GENERATOR For a forced-flow steam generator with no fixed steamline and waterline, equipped with automatic controls and protective interlocks responsive to steam pressure, safety valves may be installed in accordance with the following, as an alternative: a. One or more power-actuated pressurerelieving valves shall be provided in 392 APPENDIX I — INSTALLATION REQUIREMENTS direct communication with the boiler when the boiler is under pressure and shall receive a control impulse to open when the maximum allowable working pressure at the superheater outlet is exceeded. The total combined relieving capacity of the power-actuated pressure-relieving valves may be not less than 10% of the maximum design steaming capacity of the boiler under any operating condition as determined by the manufacturer. The valves shall be located in the pressure part system where they will relieve the overpressure. An isolating stop valve of the outsidescrew-and-yoke type may be installed between the power-actuating pressurerelieving valve and the boiler to permit repairs provided an alternate poweractuated pressure-relieving valve of the same capacity is so installed as to be in direct communication with the boiler. b. Spring-loaded safety valves shall be provided having a total combined relieving capacity, including that of the power-actuated pressure-relieving valve, of not less than one hundred percent of the maximum designed steaming capacity of the boiler, as determined by the manufacturer. In this total, credit in excess of 30% of the total relieving capacity may not be allowed for the power-actuated pressure-relieving valves actually installed. Any or all of the spring-loaded safety valves may be set above the maximum allowable working pressure of the parts to which they are connected, but the set pressures shall be such that when all these valves (together with the power-actuated pressure-relieving valves) are in operation the pressure will not rise more than 20% above the maximum allowable working pressure of any part of the boiler, except for the steam piping between the boiler and the prime mover. 393 c. When stop valves are installed in the water-steam flow path between any two sections of a forced-flow steam generator with no fixed steamline and waterline: 1. The power-actuated pressure-relieving valve shall also receive a control impulse to open when the maximum allowable working pressure of the component, having the lowest pressure level upstream to the stop valve, is exceeded. 2. The spring-loaded safety valve shall be located to provide overpressure protection for the component having the lowest working pressure. 3. A reliable pressure-recording device shall always be in service and records kept to provide evidence of conformity to the above requirements. I-2870 SUPERHEATERS a. Every attached superheater shall have one or more safety valves. The location shall be suitable for the service intended and shall provide the overpressure protection required. The pressure drop upstream of each safety valve shall be considered in determining the set pressure and relieving capacity of that valve. If the superheater outlet header has a full, free, steam passage from end to end and is so constructed that steam is supplied to it at practically equal intervals throughout its length so that there is a uniform flow of steam through the superheater tubes and the header, the safety valve or valves may be located anywhere in the length of header. b. The pressure relieving capacity of the safety valve or valves on an attached superheater may be included in determining the number and size of the safety valves for the boiler provided there are NATIONAL BOARD INSPECTION CODE no intervening valves between the superheater safety valve and the boiler and the discharge capacity of the safety relief valve or valves, on the boiler, as distinct from the superheater, is at least 75% of the aggregate capacity required. c. Every independently fired superheater that may be shut off from the boiler and permit the superheater to become a fired pressure vessel shall have one or more safety valves having a discharge capacity equal to six pounds of steam per/hr./sq. ft. (29 kg. per sq. m.) of superheater surface measured on the side exposed to the hot gases. d. Every safety valve used on a superheater discharging superheated steam at a temperature over 450°F (230°C) shall have a casing, including the base, body, bonnet, and spindle constructed of steel, steel alloy, or equivalent heat-resistant material. The valve shall have a flanged inlet connection or a welding-end inlet connection. The seat and disk shall be constructed of suitable heat-erosive and corrosive-resistant material, and the spring fully exposed outside of the valve casing so that it is protected from contact with the escaping steam. I-2871 ECONOMIZERS An economizer that may not be isolated from a boiler does not require a safety relief valve. Economizers which may be isolated from a boiler or other heat transfer device, allowing the economizer to become a fired pressure vessel, shall have a minimum of one safety relief valve. Discharge capacity, rated in lbs./hr (kg/hr), of the safety relief valve or valves shall be calculated from the maximum expected heat absorbtion rate in BTU/hr (Joules/hr) of the economizer, and will be determined from manufacturer date, divided by 1000. The safety relief valve shall be located as close as possible to the economizer outlet. I-2880 PRESSURE-REDUCING VALVES a. Where pressure-reducing valves are used, one or more safety or safety relief valves shall be installed on the low pressure side of the reducing valve in those installations where the piping or equipment on the low pressure side does not meet the requirements for the steam supply piping. b. The safety or safety relief valves shall be located as close as possible to the pressure reducing valve. c. Capacity of the safety or safety relief valves shall not be less than the total amount of steam that can pass from the high pressure side to the low pressure side and be such that the pressure rating of the lower pressure piping or equipment shall not be exceeded. d. The use of hand-controlled bypasses around reducing valves is permissible. The bypass around a reducing valve may not be greater in capacity than the reducing valve unless the piping or equipment is adequately protected by safety or safety relief valves or meets the requirements of the high pressure system. I-2890 MOUNTING AND DISCHARGE REQUIREMENTS a. Every boiler shall have outlet connections for the safety or safety relief valve, or valves, independent of any other outside steam connection, the area of 394 APPENDIX I — INSTALLATION REQUIREMENTS opening shall be at least equal to the aggregate areas of inlet connections of all of the attached safety or safety relief valves. An internal collecting pipe, splash plate, or pan may be used, provided the total area for inlet of steam thereto is not less than twice the aggregate areas of the inlet connections of the attached safety or safety relief valves. The holes in such collecting pipes shall be at least 1/4 in. (6 mm) in diameter and the least dimension in any other form of opening for inlet of steam shall be 1/4 in. (6 mm). If safety or safety relief valves are attached to a separate steam drum or dome, the opening between the boiler proper and the steam drum or dome shall be not less than ten times the total area of the safety valve inlet. b. Every safety or safety relief valve shall be connected so as to stand in an upright position with spindle vertical. c. The opening or connection between the boiler and the safety or safety relief valve shall have at least the area of the valve inlet. No valve of any description may be placed between the safety or safety relief valves and the boiler, nor on the discharge pipe between the safety or safety relief valves and the atmosphere. When a discharge pipe is used, the cross-sectional area shall not be less than the full area of the valve outlet or of the total of the areas of the valve outlets, discharging thereinto and shall be as short and straight as possible and arranged to avoid undue stresses on the valve or valves. d. When two or more safety valves are used on a boiler, they may be mounted either separately or as twin valves made by placing individual valves on Y-bases, or duplex valves having two valves in the same body casing. Twin valves made 395 by placing individual valves on Y-bases or duplex valves having two valves in the same body shall be of equal size. e. When two valves of different sizes are mounted singly, the relieving capacity of the smaller valve shall not be less than 50% of that of the larger valve. f. When a boiler is fitted with two or more safety relief valves on one connection, this connection to the boiler shall have a cross-sectional area not less than the combined areas of inlet connections of all the safety relief valves with which it connects. g. All safety or safety relief valves shall be piped to a safe point of discharge so located or piped as to be carried clear from running boards or platforms. Ample provision for gravity drain shall be made in the discharge pipe at or near each safety or safety relief valve, and where water or condensation may collect. Each valve shall have an open gravity drain through the casing below the level of the valve seat. For iron- and steel- bodied valves exceeding NPS 2 (DN 50), the drain hole shall be tapped not less than NPS 3/8 (DN 10). h. Discharge piping from safety relief valves on high temperature water boilers shall have adequate provisions for water drainage as well as steam venting. i. If a muffler is used on a safety or safety relief valve, it shall have sufficient outlet area to prevent back pressure from interfering with the proper operation and discharge capacity of the valve. The muffler plates or other devices shall be so constructed as to avoid a possibility of restriction of the steam passages due to deposits. Mufflers shall not be used on high temperature water boiler safety relief valves. NATIONAL BOARD INSPECTION CODE I-2900 I-2910 TESTING AND ACCEPTANCE GENERAL a. Care shall be exercised during installation to prevent loose weld material, welding rods, small tools and miscellaneous scrap metal from getting into the boiler. Where possible, an inspection of the interior of the boiler and its appurtenances shall be made for the presence of foreign debris prior to making the final closure. I-2920 Prior to initial operation, the completed boiler, including pressure piping, water columns, super heaters, economizers, stop valves, etc., shall be pressure tested in accordance with the original code of construction. Any pressure piping and fittings such as water column, blowoff valve, feedwater regulator, super heater, economizer, stop valves, etc., which are shipped connected to the boiler as a unit, shall be hydrostatically tested with the boiler and witnessed by an Inspector. b. The Inspector shall inspect for safe operation all boilers and connected appurtenances and all pressure piping connecting them to the appurtenances and all piping up to and including the first stop valve, or the second stop valve when two are required. I-2930 c. The wall thickness of all pipe connections shall comply with the requirements of the code of construction for the boiler. I-2940 d. All threaded pipe connections shall engage at least five full threads of the pipe or fitting. e. In bolted connections, the bolts, studs and nuts shall be marked as required by the original code of construction and be fully engaged (i.e., the end of the bolt or stud shall protrude through the nut). f. Washers shall only be used when specified by the manufacturer of the part being installed. PRESSURE TEST NONDESTRUCTIVE EXAMINATION Boiler components and subcomponents shall be nondestructively examined as required by the governing code of construction. SYSTEMS TESTING Prior to final acceptance, an operational test shall be performed on the complete installation. The test data shall be recorded and the data made available to the jurisdictional authorities as evidence that the installation complies with the provisions of the governing code(s) of construction. This operational test may be used as the final acceptance of the unit. I-2950 FINAL ACCEPTANCE A boiler may not be placed into service until its installation has been inspected and accepted by the appropriate jurisdictional authorities. 396 APPENDIX I — INSTALLATION REQUIREMENTS I-2960 BOILER INSTALLATION REPORT I-3122 a. Upon completion, inspection and acceptance of the installation, the installer shall complete and certify the Boiler Installation Report (Report I-1). b. The I-1 Boiler Installation report shall be submitted as follows: 1. One copy to the owner 2. One copy to the jurisdiction, if required. I-3000 HEATING BOILERS AND POTABLE WATER HEATERS I-3100 INTRODUCTION I-3110 SCOPE I-3121 STEAM HEATING BOILERS Hot water heating and hot water supply boilers are hot water boilers installed to operate at pressures not exceeding 160 psi (1100 kPa) and/or temperatures not exceeding 250°F (120°C), at or near the boiler outlet. POTABLE WATER HEATERS a. Potable water heaters are corrosion resistant water heaters supplying potable hot water at pressures not exceeding 160 psi (1100 kPa) and temperatures not in excess of 210°F (100°C). b. Water heaters are exempted from I-3000 when none of the following limitations is exceeded: I-2000 Power Boilers I-4000 Pressure Vessels I-5000 Piping (ASME B31 Series) DEFINITIONS AND HOT WATER SUPPLY BOILERS I-3123 The scope of this section shall apply to those steam boilers, hot water boilers, and potable water heaters as defined in I-3120. For installation of items that do not fall within the scope of this section, refer to the following as applicable: I-3120 HOT WATER HEATING Steam heating boilers are steam boilers installed to operate at pressures not exceeding 15 psi (100 kPa). 397 1. Heat input of 200,000 Btu/hr (60 kW/hr) 2. Wa t e r t e m p e r a t u re o f 2 1 0 ° F (100°C) 3. Nominal water containing capacity of 120 gallons (454 l), except that they shall be equipped with safety devices in accordance with the requirements of I-3837. I-3200 CERTIFICATION, INSPECTION AND JURISDICTIONAL REQUIREMENTS I-3210 RESPONSIBILITY The owner is responsible for satisfying jurisdictional requirements for certification and documentation. When required by NATIONAL BOARD INSPECTION CODE jurisdictional rules applicable to the location of installation, the boiler shall not be operated until the required documentation has been provided to the owner and the jurisdiction. I-3220 EQUIPMENT CERTIFICATION All boilers shall have documented certification from the manufacturer indicating that the boiler complies with the requirements of the code of construction. The certification shall identify the revision level of the code of construction to which the boiler was fabricated. I-3230 masonry and/or structural supports of sufficient strength and rigidity to safely support the heating boiler and its contents without vibration in the heating boiler or its connecting piping and to allow for expansion and contraction. I-3311 a. JURISDICTIONAL REVIEW b. The owner shall determine jurisdictional requirements (i.e., certificates, permits, licenses, etc.) before operating the equipment. The owner shall obtain operating certificates, permits, etc. required by the jurisdiction prior to commencing operation. 2. In applying the requirements of (1) above, provision shall be made for localized stresses due to concentrated support loads, temperature changes, and restraint against movement of the boiler due to pressure. Lugs, hangers, brackets, saddles, and pads shall conform satisfactorily to the shape of the shell or surface to which they are attached or are in contact. INSPECTION All boilers shall be inspected after installation and prior to commencing operation. I-3300 I-3310 GENERAL REQUIREMENTS Loadings 1. The design and attachment of lugs, hangers, saddles, and other supports shall take into account the stresses due to hydrostatic head of fully flooded equipment in determining the minimum thicknesses required. Additional stresses imposed by effects other than working pressure or static head which increase the average stress by more than 10% of the allowable working stress shall also be taken into account. These effects include the weight of the component and its contents, and the method of support. a. The owner shall determine jurisdictional requirements (i.e., certificates, permits, licenses, etc.) before installing the equipment. The organization responsible for installation shall obtain all permits required by the jurisdiction prior to commencing installation. I-3240 METHODS OF SUPPORT FOR STEAM HEATING, HOT WATER HEATING AND HOT WATER SUPPLY BOILERS b. Horizontal Return Firetube Boilers 1. Boilers over 72 in. (1800 mm) in diameter A horizontal-return tubular boiler over 72 in. (1800 mm) in diameter SUPPORTS Each heating boiler shall be supported by 398 APPENDIX I — INSTALLATION REQUIREMENTS FIGURE I-3311A — Spacing and weld details for supporting lugs in pairs on horizontal-return tubular boiler �� FIGURE I-3311B — Welded bracket connection for horizontal-return tubular boiler � �� shall be supported from steel hangers by the outside-suspension type of setting, independent of the furnace wall. The hangers shall be so designed that the load is properly distributed. 2. Boilers over 54 in. (1350 mm) up to 72 in. (1800 mm) in diameter A horizontal-return tubular boiler over 54 in. (1330 mm) and up to and including 72 in. (1800 mm) in diameter shall be supported by the outside-suspension type of setting, or at four points by not less than 399 eight steel brackets set in pairs, the brackets of each pair to be spaced not over 2 in. (5 cm) apart and the load to be equalized between them. See Fig. I-3311A. 3. Boilers up to 54 in. (1350 mm) in diameter A horizontal-return boiler up to and including 54 in. (137 cm) in diameter shall be supported by the outsidesuspension type of setting, or by not less than two steel brackets on each side. NATIONAL BOARD INSPECTION CODE c. Supporting Members If the boiler is supported by structural steel work, the steel supporting members shall be so located or insulated that the heat from the furnace will not impair their strength. d. Lugs or Hangers Lugs, hangers, or brackets made of materials in accordance with the requirements of the code of construction may be attached by fusion welding provided they are attached by fillet welds along the entire periphery or contact edges. Figure I-3311B illustrates an acceptable design of hanger bracket with the additional requirement that the center pin be located at the vertical center line over the center of the welded contact surface. The bracket plates shall be spaced at least 2-1/2 in. (64 mm) apart, but this dimension shall be increased if necessary to permit access for the welding operation. The stresses computed by dividing the total load on each lug, hanger, or bracket, by the minimum cross-sectional area of the weld shall not exceed 2800 psi (19 MPa). Where it is impractical to attach lugs, hangers, or brackets by welding, studs with not less than 10 threads/in. (approx. 4 threads/cm) may be used. In computing the shearing stresses, the root area at the bottom of the thread shall be used. The shearing and crushing stresses on studs shall not exceed that permitted by the code of construction. I-3320 SETTINGS Steam heating, hot water heating and hot water supply boilers of wrought materials of the wet-bottom type having an external width of over 36 in. (900 mm) shall be supported so as to have a minimum clearance of 12 in. (300 mm) between the bottom of the boiler and the floor to facilitate inspection. When the width is 36 in. (900 mm) or less, the clearance between the bottom of the boiler and the floor line shall be not less than 6 in. (150 mm), except when any part of the wet bottom is not farther from the outer edge than 12 in. (300 mm), this clearance shall be not less than 4 in. (100 mm). Boiler insulation, saddles, or other supports shall be arranged so that inspection openings are readily accessible. I-3330 STRUCTURAL STEEL a. If the boiler is supported by structural steel work, the steel supporting members shall be so located or insulated that the heat from the furnace will not affect their strength. b. Structural steel shall be installed in accordance with jurisdictional requirements, manufacturer’s recommendations, and/or industry standards as appropriate. I-3340 CLEARANCES a. Heating boilers shall have a minimum distance of at least 36 in. (900 mm) between the top of the heating boiler and any overhead structure and at least 36 in. (900 mm) between all sides of the heating boiler and adjacent walls, structures, or other equipment. Heating boilers having manholes shall have at least 60 in. (150 mm) of clearance between the manhole opening and any wall, ceiling, piping, or other equipment that may prevent a person from entering the heating boiler. Alternative clearance in accordance with the manufacturer’s recommendations are subject to acceptance by the jurisdiction. b. Modular heating boilers that require individual units to be set side by side, front to back or by stacking shall provide clearances in accordance with the 400 APPENDIX I — INSTALLATION REQUIREMENTS manufacturer’s recommendations, subject to acceptance by the jurisdiction. c. Heating boilers shall be located so that adequate space is provided for proper operation, maintenance17, and inspection of equipment and appurtenances. I-3350 I-3351 BOILER ROOM REQUIREMENTS 5. Be equipped with handrails 42 in. (107 cm) high with an intermediate rail and 4 in. (10 cm) toeboard. b. Stairways which serve as a means of access to walkways, runways, or platforms shall not exceed an angle of 45 degrees from the horizontal and be equipped with handrails 42 in. (1000 mm) high with an intermediate grid. c. Ladders which serve as a means of access to walkways, runways, or platforms shall: EXIT AND EGRESS Two means of exit shall be provided for boiler rooms exceeding 500 sq. ft. (46 sq. m) of floor area and containing one or more boilers having a fuel capacity of 1,000,000 Btu/hr. (293 kW/hr.) or more (or equivalent electrical heat input). Each elevation shall be provided with at least two means of egress, each to be remotely located from the other. A platform at the top of a single boiler is not considered an elevation. 1. Be of metal construction and not less than 18 in. (450 mm) wide I-3352 4. Have a clearance of not less than 6-1/2 in. (170 mm) from the back of rungs to the nearest permanent object LADDERS AND RUNWAYS a. All walkways, runways, and platforms shall: 1. Be of metal construction 2. Be provided between or over the top of boilers which are more than 8 ft. (2.8 m.) high from the operating floor to afford accessibility for the operation and servicing of the boilers 3. Be constructed of safety treads, standard grating, or similar material and have a minimum width of 30 in. (775 mm) 4. Be of bolted, welded, or riveted construction 17 Maintenance – This includes the removal of tubes. 401 2. Have rungs that extend through the side members and are permanently secured 3. Have a clearance of not less than 30 in. (775 mm) from the front of rungs to the nearest permanent object on the climbing side of the ladder 5. Have a clearance width of at least 15 in. (400 mm) from the center of the ladder on either side across the front of the ladder. d. There shall be at least two permanently installed means of egress from walkways, runways, or platforms that exceed 6 ft (1800 mm) in length I-3353 VENTILATION AND COMBUSTION AIR The boiler room shall have an adequate air supply to permit clean, safe combustion, NATIONAL BOARD INSPECTION CODE minimize soot formation and maintain a minimum of 19.5% oxygen in the air of the boiler room. The combustion and ventilation air may be supplied by either an unobstructed air opening or by power ventilators or fans. a. Unobstructed air openings shall be sized on the basis of 1 sq. in. (6.5 sq. cm) free area per 2000 Btu/hr. (586 W/hr.) maximum fuel input of the combined burners located in the boiler room, or as specified in the National Fire Protection Association (NFPA) standards for oil and gas burning installations for the particular job conditions. The boiler room air supply openings shall be kept clear at all times. b. Power ventilators or fans shall be sized on the basis of 0.2 cfm (.0057 cm/m.) for each 1,000 Btu/hr. (293 W/hr.) of maximum fuel input for the combined burners of all boilers and/or water heaters located in the boiler room. c. When power ventilators or fans are used to supply combustion air, they shall be installed with interlock devices so that the burners will not operate without an adequate number of ventilators/fans in operation. d. When combustion air is supplied to the heating boiler by an independent duct, with or without the employment of power ventilators or fans, the duct shall be sized and installed in accordance with the manufacturer’s recommendations. However, ventilation for the boiler room must still be considered. I-3354 LIGHTING The boiler room should be well lighted and it should have an emergency light source for use in case of power failure. I-3355 EMERGENCY VALVES AND CONTROLS All emergency shut-off valves and controls shall be accessible from a floor, platform, walkway or runway. Accessibility shall mean within a six foot elevation of the standing space and not more than 12 in. (300 mm) horizontally from the standing space edge. I-3400 SOURCE REQUIREMENTS I-3410 WATER a. A means to add water to or fill the boiler, while not under pressure, shall be provided. A valve or threaded plug may be used to shut off the fill connection when the boiler is in service. b. Water fill connections shall be installed and provisions should be made to prevent boiler water from back-feeding into the service water supply. c. Provision should also be made in every boiler room for a convenient water supply which can be used to flush out the boiler and to clean the boiler room floor. I-3420 FUEL Fuel systems, whether coal, oil, gas or other substance shall be installed in accordance with jurisdictional and environmental requirements, manufacturer’s recommendations and/or industry standards, as applicable. I-3430 ELECTRICAL a. All wiring for controls, heat generating apparatus, and other appurtenances necessary for the operation of the boiler 402 APPENDIX I — INSTALLATION REQUIREMENTS or boilers shall be installed in accordance with the provisions of national or international standards and comply with the applicable local electrical codes. b. A manually operated remote shutdown switch or circuit breaker should be located just outside the boiler room door and marked for easy identification. Consideration should also be given to the type and location of the switch to safeguard against tampering. If the boiler room door is on the building exterior the switch should be located just inside the door. If there is more than one door to the boiler room, there should be a switch located at each door. 1. For atmospheric-gas burners, and oil burners where a fan is on a common shaft with the oil pump, the complete burner and controls should be shut off. 2. For power burners with detached auxiliaries, only the fuel input supply to the firebox need be shut off. c. Controls and Heat Generating Apparatus 1. Oil and gas-fired and electrically heated boilers and water heaters shall be equipped with suitable primary (flame safeguard) safety controls, safety limit switches, and burners or electric elements as required by a nationally or internationally recognized standard. 2. The symbol of the certifying organization18 which has investigated such equipment as having complied with a nationally recognized standard shall be affixed to the equipment 18 Organization – A certifying organization is one that provides uniform testing, examination, and listing procedures under established, nationally recognized standards, and that is acceptable to the authorities having jurisdiction. 403 and shall be considered as evidence that the unit was manufactured in accordance with that standard. 3. These devices shall be installed in accordance with jurisdictional and environmental requirements, manufacturer’s recommendations and/or industry standards as applicable. I-3500 DISCHARGE REQUIREMENTS I-3510 CHIMNEY OR STACK Chimneys or stacks shall be installed in accordance with jurisdictional and environmental requirements, manufacturer’s recommendations and/or industry standards, as applicable. I-3520 ASH REMOVAL Ash removal systems shall be installed in accordance with jurisdictional and environmental requirements, manufacturer’s recommendations and/or industry standards, as applicable. I-3530 DRAINS Unobstructed floor drains, properly located in the boiler room, will facilitate proper cleaning of the boiler room. Floor drains which are used infrequently should have water poured into them periodically to prevent the entrance of sewer gasses and odors. If there is a possibility of freezing, an environmentally safe antifreeze mixture should be used in the drain traps. Drains receiving blowdown water should be connected to NATIONAL BOARD INSPECTION CODE the sanitary sewer by way of an acceptable blowdown tank or separator or an air gap which will allow the blowdown water to cool to at least 140°F (60°C) and reduce the pressure to 5 psig (35 kPa) or less. I-3600 OPERATING SYSTEMS I-3610 OIL HEATERS return piping system. Alternatively, feedwater or water treatment may be introduced through an independent connection. The water flow from the independent connection shall not discharge directly against parts of the boiler exposed to direct radiant heat from the fire. Feedwater or water treatment shall not be introduced through openings or connections provided for inspection or cleaning, safety valve, water column, water gage glass, or pressure gage. The feedwater pipe shall be provided with a check valve near the boiler and a stop valve or cock between the check valve and the boiler or between the check valve and the return pipe system. a. A heater for oil or other liquid harmful to boiler operation shall not be installed directly in the steam or water space within a boiler. b. Where an external-type heater for such service is used, means shall be provided to prevent the introduction into the boiler of oil or other liquid harmful to boiler operation. I-3620 BREECHING AND DAMPERS Breeching and dampers shall be installed in accordance with jurisdictional and environmental requirements, manufacturer’s recommendations and/or industry standards, as applicable. I-3630 BURNERS AND STOKERS Burners and stokers shall be installed in accordance with jurisdictional and environmental requirements, manufacturer’s recommendations and/or industry standards, as applicable. I-3640 b. Hot Water Boilers Makeup water may be introduced into a boiler through the piping system or through an independent connection. The water flow from the independent connection shall not discharge directly against parts of the boiler exposed to direct radiant heat from the fire. Makeup water shall not be introduced through openings or connections provided exclusively for inspection or cleaning, safety relief valve, pressure gage, or temperature gage. The makeup water pipe shall be provided with a check valve near the boiler and a stop valve or cock between the check valve and the boiler or between the check valve and the piping system. c. Potable Water Heaters 1. Water supply shall be introduced into a water heater through an independent water supply connection. Feedwater shall not be introduced through openings or connections provided for cleaning, safety relief valves, drain, pressure gage, or temperature gage. FEEDWATER, MAKEUP WATER, AND WATER SUPPLY a. Steam Boilers Feedwater or water treatment shall be introduced into a boiler through the 404 APPENDIX I — INSTALLATION REQUIREMENTS 2. If the water supply pressure to a water heater exceeds 75% of the set pressure of the safety relief valve, a pressure reducing valve is required. I-3650 STOP VALVES I-3651 STEAM HEATING, HOT WATER HEATING AND HOT WATER SUPPLY BOILERS addition, all plug-type cocks shall be equipped with a guard or gland. The plug or other operating mechanism shall be distinctly marked in line with the passage to indicate whether it is opened or closed. 5. All valves or cocks shall have tight closure when under boiler hydrostatic test pressure. I-3652 a. For Single Installations Stop valves shall be located at an accessible point in the supply and return pipe connections, as near the boiler as is convenient and practicable. b. For Multiple Boiler Installations A stop valve shall be used in each supply and return pipe connection of two or more boilers connected to a common system. See Figures I-3651A, I-3651B, and I-3651C. c. Type of Stop Valve(s) 1. All valves or cocks shall conform with the applicable portions of an acceptable code of construction and may be ferrous or nonferrous. 2. The minimum pressure rating of all valves or cocks shall be at least equal to the pressure stamped upon the boiler, and the temperature rating of such valves or cocks, including all internal components, shall be not less than 250°F (120°C). 3. Valves or cocks shall be flanged, threaded or have ends suitable for welding or brazing. 4. All valves or cocks with stems or spindles shall have adjustable pressure-type packing glands and, in 405 POTABLE WATER HEATERS Stop valves shall be installed in the supply and discharge pipe connections of a water heater installation to permit draining the water heater without emptying the system. I-3660 RETURN PIPE CONNECTIONS a. The return pipe connections of each boiler supplying a gravity return steam heating system shall be so arranged as to form a loop substantially as shown in Figure I-3651B so that the water in each boiler cannot be forced out below the safe water level. b. For hand-fired boilers with a normal grate line, the recommended pipe sizes detailed as “A” in Fig. I-3651A and I-3651B are NPS 1-1/2 (DN 40) for 4 sq. ft. (0.37 sq. m.) or less firebox area at the normal grate line, NPS 2-1/2 (DN 65) for areas more than 4 sq. ft. (0.37 sq m) up to 14.9 sq. ft. (1.38 sq. m.), and NPS 4 (DN 100) for 15 sq. ft. (1.39 sq. m.) or more. c. For automatically fired boilers which do not have a normal grate line, the recommended pipe sizes detailed as “A” in Figures I-3651A and I-3651B are NPS 1-1/2 (DN 40) for boilers with minimum required safety valve relieving capacity 250 lb./hr. (113 kg./hr.) or less, NPS 2- NATIONAL BOARD INSPECTION CODE FIGURE I-3651-a — Steam boilers in battery – pumped return – acceptable piping installation Drip pan elbow Stop valve Alternative safety valve discharge piping [Note (1)] Steam main Steam gage Pressure controls “A” Low-water fuel cutoff pump control and gage glass Safety valve F & T trap high level “spill” To receiver tank Pressure controls Safety valve Stop valve Solenoid valve F & T trap high level “spill” Blowoff valve/drain From receiver tank Heating supply Steam gage Safety valve discharge piping (with union) Multiple Returns Shown Check valve Stop valve To receiver tank Pump control and gage glass Low-water fuel cutoff Safety valve discharge piping (with union) Stop valve Check valve Blowoff valve/drain Solenoid valve Single Return Shown From receiver tank General Note: Return connections shown for a multiple boiler installation may not always insure that the system will operate properly properly. In order to maintain proper water levels in multiple boiler installations, it may be necessary to install supplementary controls or suitable devices. Note: (1) Recommended for 1 in. and larger safety valve discharge. 1/2 (DN 65) for boilers with minimum required safety valve relieving capacity from 251 lb./hr. (114 kg./hr.) to 2000 lb./ hr. (987 kg./hr.), inclusive, and NPS 4 (DN 100) for boilers with more than 2000 lb./hr. (987 kg./hr.) minimum required safety valve relieving capacity. d. Provision shall be made for cleaning the interior of the return piping at or close to the boiler. Washout openings may be used for return pipe connections and the washout plug placed in a tee or a cross so that the plug is directly opposite and as close as possible to the opening in the boiler. I-3670 BOTTOM BLOWOFF AND DRAIN VALVES I-3671 STEAM HEATING, HOT WATER HEATING AND HOT WATER SUPPLY BOILERS a. Bottom Blowoffs Each steam boiler shall have a bottom blowoff connection fitted with a valve or cock connected to the lowest water space practicable with a minimum size as shown in Table I-3671A. The dis- 406 APPENDIX I — INSTALLATION REQUIREMENTS FIGURE I-3651-b — Steam boilers in battery – gravity return – acceptable piping installation Stop valve Drip pan elbow Steam gage Alternative satety valve discharge piping [Note (1)] “A” To return header F & T trap Safety valve Return loop connection Steam main Pressure controls Lowest Permissible waterline Heating supply Stop valve Low-water fuel cutoff and gage glass Steam gage Safety valve discharge piping (with union) Pressure controls Safety valve Multiple Returns Shown Stop valve Low-water fuel cutoff Water column and gage glass Safety valve discharge piping (with union) Check valve Blowoff valve/drain Single Return Shown Stop valve Check valve Blowoff valve/drain Heating return General Note: Return connections shown for a multiple boiler installation may not always insure that the system will operate properly. In order to maintain proper water levels in multiple boiler installations, it may be necessary to install supplementary controls or suitable devices. Note: (1) Recommended for 1 in. and larger safety valve discharge. charge piping shall be full size to the point of discharge. b. Boilers having a capacity of 25 gallons (95 l) or less are exempt from the above requirements, except that they shall have a NPS 3/4 (DN 20) minimum drain valve. to the lowest water containing spaces. All parts of the boiler must be capable of being drained (the boiler design will dictate the number and size of drains). The minimum size of the drain piping, valves, and cocks shall be NPS 3/4 (DN 20). The discharge piping shall be full size to the point of discharge. c. Drains Each steam or hot-water boiler shall have one or more drain connections, fitted with valves or cocks connecting When the blowoff connection is located at the lowest water containing space, a separate drain connection is not required. 407 NATIONAL BOARD INSPECTION CODE FIGURE I-3651-c — Hot-water boilers in battery – acceptable piping installation Heating supply External low-water fuel cut-off (1) High limit control Preferred location of circulating pump Stop valve Temperature pressure gage Expansion tank Maximum temperature limit control Safety relief valve Stop valve Safety relief valve dischagre piping (with union) Make-up water Temperature pressure gage Pressure reducing valve Drain valve Heating return Safety relief valve Check valve Stop valve (2) Check valve Air vent High limit control Safety relief valve discharge piping (with union) Internal low-water fuel cut-off (alternate arrangement) Maximum temperature limit control Stop valve (2) Drain valve Alternate make-up water arrangement Pressure reducing valve Alternate expansion tank with diaphragm (required on each boiler) General Notes: (1) Recommended control. See HG-614. Acceptable shutoff valves or cocks in the connecting piping may be installed for convenience of control testing and/or service. (2) The common return header stop valves may be located on either side of the check valves. d. Minimum Pressure Rating The minimum pressure rating of valves and cocks used for blowoff or drain purposes shall be at least equal to the pressure stamped on the boiler but in no case less than 30 psi (200 kPa). The temperature rating of such valves and cocks shall not be less than 250°F (120°C). I-3672 POTABLE WATER HEATERS a. Drain Valve 1. Each water heater shall have a bottom drain pipe connection fitted with a valve or cock connected with the lowest water space practicable. The minimum size bottom valve shall be NPS 3/4 (DN 20). 408 APPENDIX I — INSTALLATION REQUIREMENTS FIGURE I-3651-d — A typical acceptable piping installation for storage water heaters in battery Expansion Tank if Required Drain Valve with Suitable Drain Point of Use Water Heater with Side Safety Relief Opening & within 4 in. of the top of the shell Water Heater with Vertical Top Safety Relief Opening Pressure Reducing Valve if Required To Open Drain To Open Drain Cold Water Supply Drain Valve Water Heater with Top Relief Opening Drain Valve Optical Recirculation Line [Note (1)] Water Heater with Side Relief Opening Note: (1) Recirculation system may be gravity or pump actuated. FIGURE I-3651-e — A typical acceptable piping installation for flow through water heater with provisions for piping expansion Flow switch on flow through water heater Drain valve 409 Optical recirculation line NATIONAL BOARD INSPECTION CODE 2. Any discharge piping connected to the bottom drain connection shall be full size to the point of discharge. I-3680 I-3681 MODULAR STEAM HEATING AND HOT WATER HEATING BOILERS maximum input of 400,000 Btu/hr. (gas) (117 kW/hr.), 3 gal./hr. (oil) (11.4 l/hr.), or 117 kW (electricity). b. Each module of a modular steam heating boiler shall be equipped with: 1. Safety valve, see I-3810 2. Blowoff valve, see I-3671(a) INDIVIDUAL MODULES a. The individual modules shall comply with all the requirements of the code of construction and this paragraph. The individual modules shall be limited to a 3. Drain valve, see I-3671(c). c. Each module of a modular hot water heating boiler shall be equipped with: 1. Safety relief valve, see I-3820 2. Drain valve, see I-3671(c). TABLE I-3651.2 — Expansion Tank Capacities for a Water Heater (Note 1) Tank Capacities, gal System Volume, gal (l) 50 (190) 100 (380) 200 (760) 300 (1150) 400 (1520) 500 (1900) 1,000 (3800) 2,000 (7600) Prepressurized Diaphragm Type Nonpressurized Type 1 2 3 4 5 6 12 24 3 6 12 18 24 30 60 120 I-3682 ASSEMBLED MODULAR BOILERS a. The individual modules shall be manifolded together at the job-site without any intervening valves. b. The assembled modular steam heating boiler shall also be equipped with: 1. Feedwater connection, see I-3640 2. Return pipe connection, see I-3660. Note 1: Capacities in this table are given as a guide to reduce or eliminate relief valve weeping under conditions of partial water system demands or occasional water draw during recovery. TABLE I-3671A — Size of Bottom Blowoff Piping, Valves and Cocks Minimum Required Safety Valve Capacity, lb of steam/hr (Note 1) System volume includes water heater capacity plus all piping capacity for a recirculation system or water heater capacity only for a nonrecirculation system. up to 500 501 to 1,250 1,251 to 2,500 2,501 to 6,000 6,001 and larger The capacities are based upon a water temperature rise from 40°F to 180°F (4°C to 80°C), 60 psi fill pressure, maximum operating pressure of 125 psi, 20% water recovery, and an acceptance factor of 0.465 for prepressurized types and 0.09156 for nonprepres-surized types. A procedure for estimating tank sizes for other design conditions may be found in Chapter 12 of the 1996 HVAC Systems and Equipment volume of the ASHRAE Handbook. Blowoff Piping, Valves and Cocks Size, in. (mm) (min.) 3/4 (19) 1 (25) 1-1/4 (32) 1-1/2 (38) 2 (50) Note 1: To determine the discharge capacity of safety relief valves in terms of Btu, the relieving capacity in lb of steam/hr is multiplied by 1,000. 410 APPENDIX I — INSTALLATION REQUIREMENTS c. The assembled modular hot water boiler shall also be equipped with: 1. Makeup water connection, see I-3640 2. Provision for thermal expansion, see I-3690 3. Stop valves, see I-3651(a) (treating the assembled modular boiler as a single unit). I-3690 I-3691 PROVISIONS FOR THERMAL EXPANSION IN HEATING BOILERS pressure of 75 psi (525 kPa). Expansion tanks for systems designed to operate above 30 psi (200 kPa) shall be constructed in accordance with an acceptable code of construction. Provisions shall be made for draining the tank without emptying the system, except for prepressurized tanks. The minimum capacity of the closed type expansion tank may be determined from Tables I-3691A and I-3691B or from the following formula where the necessary information is available: Vt = where, Vt = EXPANSION TANKS AND PIPING FOR STEAM HEATING, HOT-WATER HEATING AND HOTWATER SUPPLY BOILERS Vs = T= a. Expansion Tanks for Hot-Water Heating and Hot-Water Supply Boilers All hot-water heating systems incorporating hot-water tanks or fluid relief columns shall be so installed as to prevent freezing under normal operating conditions. 1. Heating Systems With Open Expansion Tank An indoor overflow from the upper portion of the expansion tank shall be provided in addition to an open vent, the indoor overflow shall be carried within the building to a suitable plumbing fixture or drain. 2. Closed Heating Systems An expansion tank shall be installed that will be consistent with the volume and capacity of the system. If the system is designed for a working pressure of 30 psi (200 kPa) or less, the tank shall be suitably designed for a minimum hydrostatic test 411 Pa = Pf = Po = [(0.00041T-0.0466)Vs]/ [(Pa/Pf) - (Pa/Po)] minimum volume of tanks, gallons (l) volume of system, not including tanks, gallons (l) average operating temperature, °F (°C) atmospheric pressure, psia (kPa) fill pressure, psia (kPa) maximum operating pressure, psia (kPa) 3. Hot-Water Supply Systems If a system is equipped with a check valve or pressure reducing valve in the cold water inlet line, consideration should be given to the installation of an airtight expansion tank or other suitable air cushion. Otherwise due to the thermal expansion of the water, the safety relief valve may lift periodically. If an expansion tank is provided, it shall be constructed in accordance with an acceptable code of construction. Except for pre-pressurized tanks, which should be installed on the cold water side, provisions shall be made for draining the tank without emptying the system. See Fig. I-3651D for a typical acceptable installation. NATIONAL BOARD INSPECTION CODE b. Piping for Steam Heating, Hot-Water Heating and Hot-Water Supply Boilers Provisions shall be made for the expansion and contraction of steam and hot water mains connected to boiler(s) so there will be no undue strain transmitted to the boiler(s). See Figs. I-3651A, I3651B, and I-3651C for typical schematic arrangements of piping incorporating strain absorbing joints for steam and hot water heating boilers. I-3692 EXPANSION TANKS AND PIPING FOR POTABLE WATER HEATERS a. Expansion Tanks If a system is equipped with a check valve or pressure-reducing valve in the cold water inlet line, consideration should be given to the installation of an airtight expansion tank or other suitable air cushion. Otherwise, due to the thermal expansion of the water, the safety relief valve may lift periodically. If an expansion tank is provided, it shall be constructed in accordance with an acceptable code of construction. The minimum capacity of the expansion tank may be determined from Table I-3651.2. See Fig. I-3651D for a typical acceptable installation. Except for prepressurized diaphragm type tanks, which should be installed on the cold water side, provisions shall be made for draining the tank without emptying the system. I-3700 INSTRUMENTS, FITTINGS, AND CONTROLS I-3710 STEAM HEATING BOILERS I-3711 STEAM GAGES a. Each steam boiler shall have a steam gage or a compound steam gage connected to its steam space or to its water column or to its steam connection. The gage or connection shall contain a siphon or equivalent device which will develop and maintain a water seal that will prevent steam from entering the gage tube. The connection shall be so arranged that the gage cannot be shut off from the boiler except by a cock placed in the pipe at the gage and provided TABLE I-3691A — Expansion Tank Capacities for Gravity Hot Water Systems (Based on two-pipe system with average operating water temperature 170°F (77°C), using case iron column radiation with heat emission rate 150 Btu/hr sq. ft. (44 W/hr sq. 0.3 m) equivalent direction radiation.) b. Piping Provisions shall be made for the expansion and contraction of hot water mains connected to water heater(s) so that there will be no undue strain transmitted to the water heater(s). See Figures I-3651D and I-3651E for typical schematic arrangements of piping incorporating strain absorbing joints. Installed Equivalent Direct Radiation, sq. ft. (Note 1) Tank Capacity, gallon up to 350 up to 450 up to 650 up to 900 up to 1,100 up to 1,400 up to 1,600 up to 1,800 up to 2,000 up to 2,400 18 21 24 30 35 40 2- 30 2- 30 2- 35 2- 40 Note 1: For systems with more than 2,400 sq. ft. of installed equivalent direct water radiation, the required capacity of the cushion tank shall be increased on the basis of 1 gal tank capacity/33 sq. ft. of additional equivalent direct radiation. 412 APPENDIX I — INSTALLATION REQUIREMENTS with a tee- or lever- handle arranged to be parallel to the pipe in which it is located when the cock is open. The connections to the boiler shall be not less than NPS 1/4 (DN 8). Where steel or wrought iron pipe or tubing is used, the connection and external siphon shall be not less than NPS 1/2(DN 15). The minimum size of a siphon if used, shall be NPS 1/4 (DN 8). Ferrous and nonferrous tubing having inside diameters at least equal to that of standard pipe sizes listed above may be substituted for pipe. b. The scale on the dial of a steam boiler gage shall be graduated to not less than 30 psi (200 kPa) nor more than 60 psi (400 kPa). The travel of the pointer from 0 psi (0 kPa) to 30 psi (200 kPa) pressure shall be at least 3 in. (75 mm). TABLE I-3691B — Expansion Tank Capacities for Forced Hot Water Systems (Note 1) (Based on average operating water temperature 195°F [91°C], fill pressure 12 psig [80 kPa], and maximum operating pressure 30 psig [200 kPa]) 100 (380) 200 (760) 300 (1150) 400 (1500) 500 (1900) 1000 (3800) 2000 (7600) Prepressurized Diaphragm Type 9 (34) 17 (65) 25 (95) 33 (125) 42 (160) 83 (315) 165 (625) WATER GAGE GLASSES a. Each steam boiler shall have one or more water gage glasses attached to the water column or boiler by means of valved fittings not less than NPS 1/2 (DN 15), with the lower fitting provided with a drain valve of a type having an unrestricted drain opening not less than NPS 1/4 (DN 8) to facilitate cleaning. Gage glass replacement shall be possible under pressure. Water glass fittings may be attached directly to a boiler. Boilers having an internal vertical height of less than 10 in. (250 mm) may be equipped with a water level indicator of the glass bulls-eye type provided the indicator is of sufficient size to show the water at both normal operating and low-water cutoff levels. b. The lowest visible part of the water gage glass shall be at least 1 in. (25 mm) above the lowest permissible water level recommended by the boiler manufacturer. With the boiler operating at this lowest permissible water level, there shall be no danger of overheating any part of the boiler. c. In electric boilers of the submerged electrode type, the water gage glass shall be so located to indicate the water levels both at startup and under maximum steam load conditions as established by the manufacturer. Tank Capacities, gal (l) System Volume, gal (l) I-3712 Nonpressurized Type 15 (57) 30 (114) 45 (170) 60 (230) 75 (285) 150 (570) 300 (1150) d. In electric boilers of the resistance element type, the lowest visible part of the water gage shall be located at least 1 in. (25 mm) above the lowest permissible water level specified by the manufacturer. Each electric boiler of this type shall also be equipped with an automatic low-water cut-off on each boiler pressure vessel so located as to automatically cut off the power supply to the heating elements before the surface of the water falls below the visible part of the glass. Note 1: System volume includes volume of water in boiler, radiation, and piping, not including the expansion tank. Expansion tank capacities are based on an acceptance factor of 0.4027 for prepressurized types and 0.222 for nonpressurized types. A procedure for estimating systemvolume and determining expansion tank sized for other design conditions may be found in Chapter 12 of the 1996 HVAC Systems and Equipment Volume of the ASHRAE Handbook. 413 NATIONAL BOARD INSPECTION CODE e. Tubular water glasses on electric boilers having a normal water content not exceeding 100 gallons (380 l) shall be equipped with a protective shield. NOTE: Transparent material other than glass may be used for the water gage provided that the material will remain transparent and has proved suitable for the pressure, temperature, and corrosive conditions expected in service. I-3713 WATER COLUMN AND WATER LEVEL CONTROL PIPES a. The minimum size of ferrous or nonferrous pipes connecting a water column to a steam boiler shall be NPS 1 (DN 25). No outlet connections, except for damper regulator, feedwater regulator, steam gages, or apparatus which does not permit the escape of any steam or water except for manually operated blowdown, shall be attached to a water column or the piping connecting a water column to a boiler (see I-3640[a]) for introduction of feedwater into a boiler). If the water column, gage glass, low-water fuel cut-off, or other water level control device is connected to the boiler by pipe and fittings, no shutoff valves of any type shall be placed in such pipe and a cross or equivalent fitting to which a drain valve and piping may be attached shall be placed in the water piping connection at every right angle turn to facilitate cleaning. The water column drain pipe and valve shall be not less than NPS 3/4 (DN 20). b. The steam connections to the water column of a horizontal firetube wrought boiler shall be taken from the top of the shell or the upper part of the head, and the water connection shall be taken from a point not above the center line of the shell. For a cast-iron boiler, the steam connection to the water column shall be taken from the top of an end section or the top of the steam header, and the water connection shall be made on an end section not less than 6 in. (150 mm) below the bottom connection to the water gage glass. I-3714 PRESSURE CONTROL Each automatically fired steam boiler shall be protected from overpressure by two pressure-operated controls. a. Each individual automatically fired steam boiler shall have a safety limit control that will cut off the fuel supply to prevent steam pressure from exceeding the 15 psi (100 kPa) maximum allowable working pressure of the boiler. Each control shall be constructed to prevent a pressure setting above 15 psi (100 kPa). b. Each individual steam boiler or each system of commonly connected steam boilers shall have a control that will cut off the fuel supply when the pressure reaches an operating limit, which shall be less than the maximum allowable pressure. c. Shutoff valves of any type shall not be placed in the steam pressure connection between the boiler and the controls described in (a) and (b) above. These controls shall be protected with a siphon or equivalent means of maintaining a water seal that will prevent steam from entering the control. The connections to the boiler shall not be less than NPS 1/4 (DN 8), but where steel or wrought iron pipe or tubing is used, they shall not be less than NPS 1/2 (DN 15). The minimum size of an external siphon shall be NPS 1/4 (DN 8) or 3/8 in. (10 mm) 414 APPENDIX I — INSTALLATION REQUIREMENTS O.D. nonferrous tubing. For manifold connections, the minimum size shall be as specified in the original code of construction. I-3715 I-3716 MODULAR STEAM HEATING BOILERS a. Each module of a modular steam boiler shall be equipped with: 1. Steam gage, see I-3711 AUTOMATIC LOW-WATER FUEL CUT-OFF AND/OR WATER FEEDING DEVICE 2. Water gage glass, see I-3712 a. Each automatically fired steam- or vapor-system boiler shall have an automatic low-water fuel cutoff so located as to automatically cut off the fuel supply when the surface of the water falls to the lowest visible part of the water gage glass. If a water feeding device is installed, it shall be so constructed that the water inlet valve cannot feed water into the boiler through the float chamber and so located as to supply requisite feedwater. b. Such a fuel cutoff or water feeding device may be attached directly to a boiler. A fuel cut-off or water feeding device may also be installed in the tapped openings available for attaching a water glass direct to a boiler, provided the connections are made to the boiler with nonferrous tees or Y’s not less than NPS 1/2 (DN 15) between the boiler and water glass so that the water glass is attached directly and as close as possible to the boiler; the run of the tee or Y shall take the water glass fittings, and the side outlet or branch of the tee or Y shall take the fuel cut-off or water feeding device. The ends of all nipples shall be reamed to full-size diameter. c. Fuel cutoffs and water feeding devices embodying a separate chamber shall have a vertical drain pipe and a blowoff valve not less than NPS 3/4 (DN 20), located at the lowest point in the water equalizing pipe connections so that the chamber and the equalizing pipe can be flushed and the device tested. 415 3. Pressure control, see I-3714(a) 4. Low water cutoff, see I-3715. b. The assembled modular steam heating boiler shall also be equipped with a pressure control. See I-3714(b). I-3717 INSTRUMENTS, FITTINGS, AND CONTROLS MOUNTED INSIDE BOILER JACKETS Any or all instruments, fittings, and controls required by these rules may be installed inside of boiler jackets provided the water gage and pressure gage on a steam boiler are visible through an opening or openings at all times. I-3720 HOT WATER HEATING OR HOT WATER SUPPLY BOILERS I-3721 PRESSURE OR ALTITUDE GAGES a. Each hot water heating or hot water supply boiler shall have a pressure or altitude gage connected to it or to its flow connection in such a manner that it cannot be shut off from the boiler except by a cock with tee or lever handle, placed on the pipe near the gage. The handle of the cock shall be parallel to the pipe in which it is located when the cock is open. NATIONAL BOARD INSPECTION CODE b. The scale on the dial of the pressure or altitude gage shall be graduated approximately to not less than 1-1/2 nor more than 3-1/2 times the pressure at which the safety relief valve is set. c. Piping or tubing for pressure or altitude gage connections shall be of nonferrous metal when smaller than NPS 1 (DN 25). I-3722 THERMOMETERS Each hot water heating or hot water supply boiler shall have a thermometer so located and connected that it shall be easily readable. The thermometer shall be so located that it shall at all times indicate the temperature of the water in the boiler at or near the outlet. I-3723 TEMPERATURE CONTROL Each automatically fired hot water heating or hot water supply boiler shall be protected from over-temperature by two temperatureoperated controls. a. Each individual automatically fired hot water heating or hot water supply boiler shall have a safety limit control that will cut off the fuel supply to prevent water temperature from exceeding the maximum allowable temperature at the boiler outlet. This water temperature safety control shall be constructed to prevent a temperature setting above the maximum allowable temperature. b. Each individual hot water heating or hot water supply boiler or each system of commonly connected boilers without intervening valves shall have a control that will cut off the fuel supply when the water temperature reaches an operating limit, which shall be less than the maximum allowable temperature. I-3724 LOW WATER FUEL CUTOFF a. Each automatically fired hot water boiler with heat input greater than 400,000 Btu/hr (117 kW/hr.) shall have an automatic low-water fuel cutoff which has been designed for hot water service, and it shall be so located as to automatically cut off the fuel supply when the surface of the water falls to the level established in (b) below. b. As there is no normal waterline to be maintained in a hot-water boiler, any location of the low-water fuel cut-off above the lowest safe permissible water level established by the boiler manufacturer is satisfactory. c. A coil-type boiler or a watertube boiler with heat input greater than 400,000 Btu/hr. (117 kW/hr.) requiring forced circulation to prevent overheating of the coils or tubes shall have a flow-sensing device installed in lieu of the low-water fuel cut-off required in (a) above to automatically cut off the fuel supply when the circulating flow is interrupted. d. A means shall be provided for testing the operation of the external low-water fuel cutoff without resorting to draining the entire system. Such means shall not render the device inoperable except as follows. If the means temporarily isolates the device from the boiler during this testing, it shall automatically return to its normal position. The connection may be so arranged that the device cannot be shut off from the boiler except by a cock placed at the device and provided with a tee or lever-handle arranged to be parallel to the pipe in which it is located when the cock is open. 416 APPENDIX I — INSTALLATION REQUIREMENTS I-3725 MODULAR HOT WATER HEATING BOILERS a. Each module of a modular hot water heating boiler shall be equipped with: 1. Pressure/altitude gage, see I-3721 2. Thermometer, see I-3722 3. Temperature control, see I-3723(a). b. The assembled modular hot water heating boiler shall be equipped with: 1. Temperature control, see I-3723(b) INSTRUMENTS, FITTINGS, AND CONTROLS MOUNTED INSIDE BOILER JACKETS I-3731 c. On oil-fired water heaters, the high limit temperature control when actuated shall cut off all current flow to the burner mechanism. I-3732 Any or all instruments, fittings, and controls required by these rules may be installed inside of boiler jackets provided the thermometer and pressure gage are visible through an opening or openings at all times. I-3730 b. On electrically heated water heaters, the high limit temperature control when actuated shall cut off all power to the operating controls. d. On indirect water heating systems, the high limit temperature control when activated shall cut off the source of heat. 2. Low water fuel cutoff, see I-3724. I-3726 ated shall shut off the fuel supply with a shutoff means other than the operating control valve. Separate valves may have a common body. Each installed water heater shall have a thermometer so located and connected that it shall be easily readable. The thermometer shall be so located that it shall at all times indicate the temperature of the water in the water heater at or near the outlet. I-3800 PRESSURE RELIEVING VALVES I-3810 SAFETY VALVE REQUIREMENTS FOR STEAM BOILERS POTABLE WATER HEATERS TEMPERATURE CONTROLS Each individual automatically fired water heater, in addition to the operating control used for normal water heater operation shall have a separate high limit temperature actuated combustion control that will automatically cut off the fuel supply. The temperature range of the high limit temperature actuated control shall not allow a setting over 210°F (100°C). a. On gas-fired water heaters, the high limit temperature control when actu- 417 THERMOMETER a. Safety valves are to be manufactured in accordance with a national or international standard. b. Each steam boiler shall have one or more National Board capacity certified safety valves of the spring pop type adjusted and sealed to discharge at a pressure not to exceed 15 psi (100 kPa). NATIONAL BOARD INSPECTION CODE c. No safety valve for a steam boiler shall be smaller than NPS 1/2 (DN 15). No safety valve shall be larger than NPS 4-1/2 (DN 115). The inlet opening shall have an inside diameter equal to, or greater than, the seat diameter. d. The minimum valve capacity in pounds (kilograms) per hour shall be the greater of that determined by dividing the maximum Btu (Watts) output at the boiler nozzle obtained by the firing of any fuel for which the unit is installed by 1000, or shall be determined on the basis of the pounds (kilograms) of steam generated per hour per square foot (square meter) of boiler heating surface as given in Table I-3820. For cast-iron boilers, the minimum valve capacity shall be determined by the maximum output method. In many cases a greater relieving capacity of valves will have to be provided than the minimum specified by these rules. In every case, the requirement of I-3810(e) shall be met. e. The safety valve capacity for each steam boiler shall be such that with the fuel burning equipment installed, and operated at maximum capacity, the pressure cannot rise more than 5 psi (35 kPa) above the maximum allowable working pressure. f. When operating conditions are changed, or additional boiler heating surface is installed, the valve capacity shall be increased, if necessary, to meet the new conditions and be in accordance with I3810(e). The additional valves required, on account of changed conditions, may be installed on the outlet piping provided there is no intervening valve. I-3820 SAFETY RELIEF VALVE REQUIREMENTS FOR HEATING OR HOT-WATER SUPPLY BOILERS a. Safety relief valves are to be manufactured in accordance with a national or international standard b. Each hot-water heating or hot-water supply boiler shall have at least one National Board capacity certified safety relief valve, of the automatic reseating type set to relieve at or below the maximum allowable working pressure of the boiler. c. Hot-water heating or hot-water supply boilers limited to a water temperature not in excess of 210°F (100°C) may have, in lieu of the valve(s) specified in (b) above, one or more National Board capacity certified temperature and pressure safety relief valves of the automatic reseating type set to relieve at or below the maximum allowable working pressure of the boiler. d. When more than one safety relief valve is used on either hot-water heating or hot-water supply boilers, the additional valves shall be National Board capacity certified and may have a set pressure within a range not to exceed 6 psi (40 kPa) above the maximum allowable working pressure of the boiler up to and including 60 psi (400 kPa), and 5% for those having a maximum allowable working pressure exceeding 60 psi (400 kPa). e. No safety relief valve shall be smaller than NPS 3/4 (DN 20) nor larger than NPS 4-1/2 (DN 115) except that boilers having a heat input not greater than15,000 Btu/hr. (15.8 4.4 W/hr.) may be equipped with a rated safety relief valve of NPS 1/2 (DN 15). 418 APPENDIX I — INSTALLATION REQUIREMENTS f. The required steam relieving capacity, in pounds per hour, of the pressure relieving device or devices on a boiler shall be the greater of that determined by dividing the maximum output in Btu (Watts) at the boiler nozzle obtained by the firing of any fuel for which the unit is installed by 1,000, or shall be determined on the basis of pounds (kilograms) of steam generated per hour per square foot (square meter) of boiler heating surface as given in Table I-3820. For cast-iron boilers, the minimum valve capacity shall be determined by the maximum output method. In many cases a greater relieving capacity of valves will have to be provided than the minimum specified by these rules. In every case, the requirements of I-3820(h) shall be met. g. When operating conditions are changed, or additional boiler heating surface is installed, the valve capacity shall be increased, if necessary, to meet the new conditions and shall be in accordance with I-3820(h). The additional valves required, on account of changed conditions, may be installed on the outlet piping provided there is no intervening valve. h. Safety relief valve capacity for each boiler with a single safety relief valve TABLE I-3820 — Minimum Pounds of Steam per Hour per Square Foot of Heating Surface Boiler heating surface Hand-fired Stoker-fired Oil-, gas-, or pulverized-fuel-fired Firetube Boilers Watertube Boilers 5 (2112) 7 (2956) 8 (3378) 6 (2534) 8 (3378) 10 (4223) Waterwall heating surface Hand-fired Stoker-fired Oil-, gas-, or pulverized- fuel-fired 8 (3378) 10 (4223) 14 (5912) 8 (3378) 12 (5068) 16 (6756) Copper finned watertubes hand-fired Stoker-fired Oil-, gas-, or pulverized-fuel-fired 4 (1689) 5 (2112) 5 (2112) 4 (1689) 5 (2112) 6 (2534) NOTES: When a boiler is fired only by a gas having a heat value not in excess of 200 Btu per cubic foot, the minimum relieving capacity may be based on the values given for hand-fired boilers above. For firetube boiler units exceeding 8000 Btu/sq. ft. (total Fuel Btu Input divided by total heating surface), the factor from the table will be increased by 1 for every 1000 Btu./sq. ft. above 8000. For units with less than 7000 Btu/sq. ft., the factor from the table will be decreased by 1 for every 1000 Btu/sq. ft. below 7000. For watertube boiler units exceeding 16000 Btu/sq. ft. (total fuel Btu input divided by the total heating surface), the factor from the table will be increased by 1 for every 1000 Btu/sq. ft. above 16000. For units with less than 15000 Btu/sq. ft., the factor in the table will be decreased by 1 for every 1000 Btu/sq. ft. below 15000. The heating surface shall be computed for that side of the boiler surface exposed to the products of combustion, exclusive of the superheating surface. In computing the heating surface for this purpose, only the tubes, fireboxes, shells, tube sheets, and the projected area of headers need be considered, except that for vertical firetube steam boilers, only that portion of the tube surface up to the middle gage cock is to be computed. 419 NATIONAL BOARD INSPECTION CODE shall be such that, with the fuel burning equipment installed and operated at maximum capacity, the pressure cannot rise more than 10% above the maximum allowable working pressure. When more than one safety relief valve is used, the over pressure shall be limited to 10% above the set pressure of the highest set valve allowed by I-3820(b). I-3830 MOUNTING SAFETY AND SAFETY RELIEF VALVES FOR STEAM HEATING, HOT-WATER HEATING, AND HOT-WATER SUPPLY BOILERS I-3831 PERMISSIBLE MOUNTING Safety valves and safety relief valves shall be located at the top side19 of the boiler. They shall be connected directly to a tapped or flanged opening in the boiler, to a fitting connected to the boiler by a short nipple, to a Y-base, or to a valveless header connecting steam or water outlets on the same boiler. Coil- or header- type boilers shall have the safety valve or safety relief valve located on the steam or hot water outlet end. Safety valves and safety relief valves shall be installed with their spindles vertical. The opening or connection between the boiler and any safety valve or safety relief valve shall have at least the area of the valve inlet. I-3832 REQUIREMENTS FOR COMMON CONNECTIONS FOR TWO OR MORE VALVES a. When a boiler is fitted with two or more safety valves on one connection, this connection shall have a cross-sectional area not less than the combined areas of inlet connections of all the safety valves with which it connects. b. When a Y-base is used, the inlet area shall be not less than the combined outlet areas. When the size of the boiler requires a safety valve or safety relief valve larger than NPS 4-1/2 (DN 115), two or more valves having the required combined capacity shall be used. When two or more valves are used on a boiler, they may be single, directly attached or mounted on a Y-base. I-3833 THREADED CONNECTIONS A threaded connection may be used for attaching a valve. I-3834 PROHIBITED MOUNTINGS Safety and safety relief valves shall not be connected to an internal pipe in the boiler. I-3835 USE OF SHUTOFF VALVES PROHIBITED No shutoff of any description shall be placed between the safety or safety relief valve and the boiler, or on discharge pipes between such valves and the atmosphere. 19 Side – The top side of the boiler shall mean the highest practible part of the boiler proper but in no case shall the safety valve be located below the normal operating level and in no case shall the safety relief valve be located below the lowest permissible water level. 420 APPENDIX I — INSTALLATION REQUIREMENTS I-3836 SAFETY AND SAFETY RELIEF VALVE DISCHARGE PIPING a. A discharge pipe shall be used. Its internal cross-sectional area shall be not less than the full area of the valve outlet or of the total of the valve outlets discharging therein to and shall be as short and straight as possible and so arranged as to avoid undue stress on the valve or valves. A union may be installed in the discharge piping close to the valve outlet. When an elbow is placed on a safety or a safety relief valve discharge pipe, it shall be located close to the valve outlet downstream of the union. c. When the temperature and pressure safety relief valve is mounted directly on the boiler with no more than 4 in. (100 mm) maximum interconnecting piping, the valve may be installed in the horizontal position with the outlet pointed down. I-3840 SAFETY AND SAFETY RELIEF VALVES FOR TANKS AND HEAT EXCHANGERS I-3841 STEAM TO HOT WATER SUPPLY b. The discharge from safety or safety relief valves shall be so arranged that there will be no danger of scalding attendants. The safety or safety relief valve discharge shall be piped away from the boiler to the point of discharge, and there shall be provisions made for properly draining the piping. The size and arrangement of discharge piping shall be such that any pressure that may exist or develop will not reduce the relieving capacity of the relieving devices below that required to protect the boiler. When a hot water supply is heated indirectly by steam in a coil or pipe within the service limitations set forth in I-3100, the pressure of the steam used shall not exceed the safe working pressure of the hot water tank, and a safety relief valve at least NPS 1 (DN 25), set to relieve at or below the maximum allowable working pressure of the tank, shall be applied on the tank. I-3837 When high temperature water is circulated through the coils or tubes of a heat exchanger to warm water for space heating or hot water supply, within the service limitations set forth in I-3100, the heat exchanger shall be equipped with one or more National Board capacity certified safety relief valves set to relieve at or below the maximum allowable working pressure of the heat exchanger, and of sufficient rated capacity to prevent the heat exchanger pressure from rising more than 10% above the maximum allowable working pressure of the vessel. TEMPERATURE AND PRESSURE SAFETY RELIEF VALVES Hot water heating or supply boilers limited to a water temperature of 210°F (100°C) may have one or more National Board capacity certified temperature and pressure safety relief valves installed. The requirements of I-3831 through I-3836 shall be met, except as follows: a. A Y-type fitting shall not be used. b. If additional valves are used, they shall be temperature and pressure safety relief valves. 421 I-3842 20 HIGH TEMPERATURE WATER TO WATER HEAT EXCHANGER20 Exchanger – Suggested installation practices for the secondar side of heat exchangers. NATIONAL BOARD INSPECTION CODE I-3843 shall not be less than the maximum allowable input unless the water heater is marked with the rated burner input capacity of the water heater on the casing in a readily visible location, in which case the rated burner input capacity may be used as a basis for sizing the safety relief valves. The relieving capacity for electric water heaters shall be 3500 Btu/ hr. per kw. (Watts/hr./kW.) of input. In every case, the following requirements shall be met. Safety relief valve capacity for each water heater shall be such that with the fuel burning equipment installed and operated at maximum capacity the pressure cannot rise more than 10% above the maximum allowable working pressure. HIGH TEMPERATURE WATER TO STEAM HEAT EXCHANGER19 When high temperature water is circulated through the coils or tubes of a heat exchanger to generate low pressure steam, within the service limitations set forth in I-3100, the heat exchanger shall be equipped with one or more National Board capacity certified safety valves set to relieve at a pressure not to exceed 15 psi (100 kPa), and of sufficient rated capacity to prevent the heat exchanger pressure from rising more than 5 psi (35 kPa) above the maximum allowable working pressure of the vessel. For heat exchangers requiring steam pressures greater than 15 psi (100 kPa), refer to I-2000 or I-4000. I-3850 SAFETY RELIEF VALVE REQUIREMENTS FOR POTABLE WATER HEATERS a. Each water heater shall have at least one National Board capacity certified temperature and pressure safety relief valve. No safety relief valve shall be smaller than NPS 3/4 (DN 20). b. The pressure setting shall be less than or equal to the maximum allowable working pressure of the water heater. However, if any of the other components in the hot water supply system (such as valves, pumps, expansion or storage tanks, or piping) have a lesser working pressure rating than the water heater, the pressure setting for the relief valve(s) shall be based upon the component with the lowest maximum allowable working pressure rating. If more than one safety relief valve is used, the additional valve(s) may be set within a range not to exceed 10% over the set pressure of the first valve. c. The required relieving capacity in Btu/ hr. (Watts/hr.) of the safety relief valve d. If operating conditions are changed or additional heating surface is installed, the safety relief valve capacity shall be increased, if necessary, to meet the new conditions and shall be in accordance with the above provisions. In no case shall the increased input capacity exceed the maximum allowable input capacity. The additional valves required, on account of changed conditions, may be installed on the outlet piping providing there is no intervening valve. I-3851 INSTALLATION Safety relief valves shall be installed by either the installer or the manufacturer before a water heater is placed in operation. I-3852 PERMISSIBLE MOUNTINGS Safety relief valves shall be connected directly to a tapped or flanged opening in the top of the water heater, to a fitting connected to the water heater by a short nipple, to a Y-base, or to a valveless header connecting water outlets on the same heater. Safety 422 APPENDIX I — INSTALLATION REQUIREMENTS relief valves shall be installed with their spindles upright and vertical with no horizontal connecting pipe, except that, when the safety relief valve is mounted directly on the water heater vessel with no more than 4 in. (100 mm) maximum interconnecting piping, the valve may be installed in the horizontal position with the outlet pointed down. The center line of the safety relief valve connection shall be no lower than 4 in. (100 mm) from the top of the shell. No piping or fitting used to mount the safety valve shall be of nominal pipe size less than that of the valve inlet. I-3853 REQUIREMENTS FOR COMMON CONNECTION FOR TWO OR MORE VALVES b. When a Y-base is used, the inlet area shall be not less than the combined outlet areas. c. When the size of the water heater requires a safety relief valve larger than NPS 4-1/2 (DN 115), two or more valves having the required combined capacity shall be used. When two or more valves are used on a water heater, they may be single, directly attached, or mounted on a Y-base. THREADED CONNECTIONS A threaded connection may be used for attaching a valve. 423 PROHIBITED MOUNTINGS Safety relief valves shall not be connected to an internal pipe in the water heater or a cold water feed line connected to the water heater. I-3856 USE OF SHUTOFF VALVES PROHIBITED No shutoff of any description shall be placed between the safety relief valve and the water heater, or on discharge pipes between such valves and the atmosphere. I-3857 a. When a water heater is fitted with two or more safety relief valves on one connection, this connection shall have a cross-sectional area not less than the combined areas of inlet connections of all the safety release valves with which it connects. I-3854 I-3855 SAFETY RELIEF VALVE DISCHARGE PIPING a. When a discharge pipe is used, its internal cross-sectional area shall be not less that the full area of the valve outlet or of the total of the valve outlets discharging therein to, and shall be as short and straight as possible and so arranged as to avoid undue stress on the valve or valves. When an elbow is placed on a safety relief discharge pipe, it shall be located close to the valve outlet. b. The discharge from safety relief valves shall be so arranged that there will be no danger of scalding attendants. When the safety relief valve discharge is piped away from the water heater to the point of discharge, there shall be provisions for properly draining the piping and valve body. The size and arrangement of discharge piping shall be such that any pressure that may exist or develop will not reduce the relieving capacity of the relieving devices below that required to protect the water heater. NATIONAL BOARD INSPECTION CODE I-3900 I-3910 TESTING AND ACCEPTANCE PRESSURE TEST Prior to initial operation, the completed boiler, individual module, or assembled module, shall be subject to a pressure test in accordance with the requirements of the original code of construction. I-3920 FINAL ACCEPTANCE a. In addition to determining that all equipment called for is furnished and installed in accordance with the plans and specifications, all controls shall be tested by a person familiar with the control system. b. Before any new heating plant (or boiler) is accepted for operation, a final (or acceptance) inspection shall be completed and all items of exception corrected. I-3930 BOILER INSTALLATION REPORT a. Upon completion, inspection and acceptance of the installation, the installer shall complete and certify the (I-1) Boiler Installation Report. b. The I-1 Boiler Installation report shall be submitted as follows: 1. One copy to the Owner. 2. One copy to the jurisdiction, if required. I-3940 TABLES AND FIGURES a. Table I-3691A Expansion Tank Capacities for Gravity Hot-Water Systems b. Table I-3691B Expansion Tank Capacities for Forced Hot-Water Systems c. Table I-3651.2 Expansion Tank Capacities for a Hot-Water Heater d. Table I-3671A Size of Bottom Blowoff Piping, Valves and Cocks e. Table I-3820 Minimum Pounds of Steam Per Hour Per Square Foot of Heating Surface f. Figure I-3311A Spacing and Weld Details for Supporting Lugs in Pairs on Horizontal Return Tubular Boilers g. Figure I-3311B Welded Bracket Connection for Horizontal Return Tubular Boilers h. Figure I-3651A Steam Boilers in Battery Pumped Return Acceptable Piping Installation i. Figure I-3651B Steam Boilers in Battery Gravity Return Acceptable Piping Installation j. Figure I-3651C Hot-Water Boilers in Battery Acceptable Piping Installation k. Figure I-3651D Storage Water Heaters in Battery Acceptable Piping Installation l. 424 Figure I-3651E Flow Through Water Heater Without Provision for Piping Expansion Acceptable Piping Installation APPENDIX I — INSTALLATION REQUIREMENTS I-4000 PRESSURE VESSELS I-4220 I-4100 INTRODUCTION I-4110 SCOPE All pressure vessels shall have documented certification from the manufacturer indicating that the pressure vessel complies with all requirements of the code of construction. The certification shall identify the revision level of the code of construction to which the pressure vessel was fabricated. This section provides requirements for the installation of pressure vessels as defined in I-4120. For installation of items that do not fall within the scope of this section, refer to the following as applicable: I-2000 Power Boilers I-3000 Heating Boilers and Potable Water Heaters I-5000 Piping I-4120 I-4210 JURISDICTIONAL REVIEW a. The owner shall determine jurisdictional requirements, (i.e., certificates, permits, licenses, etc.) before installing the equipment. The organization responsible for installation shall obtain all permits required by the jurisdiction prior to commencing installation. PRESSURE VESSELS Pressure vessels are containers other than boilers or piping used for the containment of pressure. I-4200 I-4230 EQUIPMENT CERTIFICATION CERTIFICATION, INSPECTION AND JURISDICTIONAL REQUIREMENTS b. The owner shall determine jurisdictional requirements, (i.e., certificates, permits, licenses, etc.) before operating the equipment. The owner shall obtain operating certificates, permits, etc. required by the jurisdiction prior to commencing operation. I-4240 RESPONSIBILITY The owner is responsible for satisfying jurisdictional requirements for certification and documentation. When required by jurisdictional rules applicable to the location of installation, the pressure vessel shall not be operated until the required documentation has been provided to the owner and the jurisdiction. 425 INSPECTION All pressure vessels shall be inspected after installation and prior to commencing operation. I-4300 GENERAL REQUIREMENTS I-4310 SUPPORTS Each pressure vessel shall be safely supported. The potential for future hydrostatic pressure tests of the vessel after installation shall be considered when designing vessel supports. NATIONAL BOARD INSPECTION CODE I-4320 CLEARANCES a. All pressure vessel installations must allow sufficient clearance for normal operation, maintenance, and inspection (internal and external). b. Orientation of nozzles, manways and attachments shall be such that sufficient clearance between the nozzles, manways and attachments and the surrounding structure(s) is maintained during installation, the attachment of associated piping, and operation. I-4330 PIPING Piping loads on the vessel nozzles shall be considered. Piping loads include weight of the pipe, weight of the contents of the pipe, expansion of the pipe from temperature and pressure changes. The effects of piping vibration on the vessel nozzles shall also be considered. I-4700 I-4710 INSTRUMENTS AND CONTROLS LEVEL INDICATING DEVICES Steam drums of unfired steam boilers shall be provided with two level indicating devices. Direct level indicating devices may be connected to a single water column or connected directly to the drum and the connections and pipe shall be not less than NPS 1/2 (DN 15). Indirect level indicating devices acceptable to the jurisdiction may be used. I-4720 PRESSURE INDICATING DEVICES The need for pressure indicating devices should be considered in the design of the pressure vessel, and when required, shall be at least 25% above the highest set pressure of the pressure relief device. I-4800 PRESSURE RELIEF DEVICES All pressure vessels shall be protected by pressure relief devices in accordance with the following requirements. I-4810 DEVICE REQUIREMENTS a. Pressure relief devices are to be manufactured in accordance with a national or international standard and be certified for capacity (or resistance to flow for rupture disk devices) by the National Board. b. Dead weight or weighted lever pressure relief valves shall not be used. c. An unfired steam boiler shall be equipped with pressure relief valves as required in I-2800. d. Pressure relief devices shall be selected (i.e., material, pressure, etc.) and installed such that their proper functioning will not be hindered by the nature of the vessel’s components. I-4820 NUMBER OF DEVICES At least one device shall be provided for protection of a pressure vessel. Pressure vessels with multiple chambers with different maximum allowable working pressures shall have a pressure relief device to protect each chamber under the most severe coincident conditions. 426 APPENDIX I — INSTALLATION REQUIREMENTS I-4830 LOCATION a. The pressure relief device shall be installed directly on the pressure vessel, unless the source of pressure is external to the vessel and is under such positive control that the pressure cannot exceed the maximum allowable working pressure, then the device may be installed elsewhere in the system provided it is in communication with the vessel at all times. b. Pressure relief devices intended for use in compressible fluid service shall be connected to the vessel in the vapor space above any contained liquid, or in the piping system connected to the vapor space. c. Pressure relief devices intended for use in liquid service shall be connected below the normal liquid line. I-4840 CAPACITY a. The pressure relief device(s) shall have sufficient capacity to assure that the pressure vessel is not exposed to pressure greater than that specified in the original code of construction. b. If an additional hazard can be created by exposure of a pressure vessel to fire or other unexpected source of external heat, supplemental pressure relief devices shall be installed to provide any additional capacity which may be required. c. Vessels connected together by a system of piping not containing valves which can isolate any pressure vessel may be considered as one unit when determining capacity requirements. 427 d. Heat exchangers and similar vessels shall be protected with a pressure relief device of sufficient capacity to avoid overpressure in case of internal failure e. When a non-reclosing device is installed between a pressure relief valve and the pressure vessel, the reduction in capacity due to installation of the nonreclosing device shall be determined in accordance with the code of construction by use of a National Board certified Combination Capacity Factor (CCF). For rupture disks, if a certified combination capacity factor is not available the capacity of the pressure relief valve shall be multiplied by 0.9 and this value used as the capacity of the combination installation. f. The owner shall document the basis for selection of the pressure relief devices used, including capacity, and have such calculations available for review by the jurisdiction. I-4850 SET PRESSURE a. When a single pressure relief device is used, the set pressure marked on the device shall not exceed the maximum allowable working pressure. b. When more than one pressure relief device is provided to obtain the required capacity, only one pressure relief device set pressure needs to be at the maximum allowable working pressure. The set pressures of the additional pressure relief devices shall be such that the pressure cannot exceed the overpressure permitted by the code of construction. NATIONAL BOARD INSPECTION CODE I-4860 pacity below the required relieving capacity; or, INSTALLATION AND DISCHARGE PIPING REQUIREMENTS 2. Upon specific acceptance of the jurisdiction, when necessary for the continuous operation of processing equipment of such a complex nature that shutdown of any part is not feasible, a full area stop valve between a pressure vessel and its pressure relief device may be provided for inspection and repair purposes only. This stop valve shall be arranged so that it can be locked or sealed open, and it shall not be closed except by an authorized person who shall remain stationed there during that period of operation while the valve remains closed. The valve shall be locked or sealed in the open position before the authorized person leaves the station. a. The opening through all pipe and fittings between a pressure vessel and its pressure relief device shall have at least the area of the pressure relief device inlet. The characteristics of this upstream system shall be such that the pressure drop will not reduce the relieving capacity below that required or adversely affect the proper operation of the pressure relief device. b. A non-reclosing device installed between a pressure vessel and a pressure relief valve shall meet the requirements of I-4860(a). c. The opening in the pressure vessel wall shall be designed to provide unobstructed flow between the vessel and its pressure relief device. 3. A full area stop valve may also be placed on the discharge side of a pressure relief device when its discharge is connected to a common header for pressure relief devices to prevent discharges from these other devices from flowing back to the first device during inspection and repair. This stop valve shall be arranged so that it can be locked or sealed open, and it shall not be closed except by an authorized person who shall remain stationed there during that period of operation while the valve remains closed. The valve shall be locked and sealed in the open position before the authorized person leaves the station. This valve shall only be used when a stop valve on the inlet side of the pressure relief device is first closed. d. When two or more required pressure relief devices are placed on one connection, the inlet cross sectional area of this connection shall be sized either to avoid restricting flow to the pressure relief devices or made at least equal to the combined inlet areas of the pressure relief devices connected to it. The flow characteristics of the upstream system shall satisfy the requirements of I-4860(a). e. There shall be no intervening stop valves between the vessel and its pressure relief device(s), or between the pressure relief device(s) and the point of discharge except under the following conditions: 1. When these stop valves are so constructed or positively controlled that the closing of the maximum number of block valves at one time will not reduce the pressure relieving ca- 4. A pressure vessel in a system where the pressure originates from an outside source may have a stop valve 428 APPENDIX I — INSTALLATION REQUIREMENTS between the vessel and the pressure relief device, and this valve need not be sealed open, provided it also closes off that vessel from the source of the pressure. f. of the completed installation, including piping to the pressure gage, pressure relief device, and, if present, level control devices. Pressure relief device discharges shall be arranged such that they are not a hazard to personnel or other equipment and, when necessary, lead to a safe location for disposal of fluids being relieved. I-5000 PIPING I-5100 INTRODUCTION g. Discharge lines from pressure relief devices shall be designed to facilitate drainage or be fitted with drains to prevent liquid from collecting in the discharge side of a pressure relief device. The size of discharge lines shall be such that any pressure which may exist or develop will not reduce the relieving capacity of the pressure relief device, or adversely affect the operation of the pressure relief device. I-5110 SCOPE h. Pressure relief devices shall be installed so they are readily accessible for inspection, repair or replacement. I-4900 TESTING AND ACCEPTANCE a. The installer shall exercise care during installation to prevent loose weld material, welding rods, small tools and miscellaneous scrap metal from getting into the vessel. The installer shall inspect the interior of the vessel and its appurtenances where possible prior to making the final closures for the presence of foreign debris. b. The completed pressure vessel shall be pressure tested in the shop or in the field in accordance with the original code of construction. When required by the jurisdiction, owner or user, the Inspector shall witness the pressure test 429 This section provides requirements for the installation of pressure piping. For installation of items that do not fall within the scope of this section, refer to the following sections as applicable: I-2000 Power Boilers I-3000 Heating Boilers and Potable Water Heaters I-4000 Pressure Vessels I-5120 ADDITIONS TO EXISTING PIPING Additions to existing piping systems shall conform to this section. That portion of the existing piping system that is not part of the addition need not comply to this section provided the addition does not result in a change in piping system operation or function that would exceed the design conditions of the existing piping system or result in unsafe conditions. I-5200 CERTIFICATION, INSPECTION AND JURISDICTIONAL REQUIREMENTS I-5210 RESPONSIBILITY The owner is responsible for satisfying jurisdictional requirements for certification NATIONAL BOARD INSPECTION CODE and documentation. When required by jurisdictional rules applicable to the location of installation, the piping shall not be operated until the required documentation has been provided to the owner and the jurisdiction. I-5300 LAYOUT AND CONFIGURATION I-5310 PROXIMITY TO OTHER EQUIPMENT AND STRUCTURES I-5220 The arrangement of the piping and its appurtenances shall take into consideration the location of other structures and equipment adjacent to the piping which may result in interference and/or damage as a result of expansion, contraction, vibration or other movements. EQUIPMENT CERTIFICATION Piping shall have documented certification from the fabricator and/or installer when required by the code of construction. The certification, when required, shall identify the revision level of the code of construction to which the piping was designed, fabricated and installed. I-5230 JURISDICTIONAL REVIEW a. The owner shall determine jurisdictional requirements, (i.e., certificates, permits, licenses, etc.) before installing the equipment. The organization responsible for installation shall obtain all permits required by the jurisdiction prior to commencing installation. b. The owner shall determine jurisdictional requirements, (i.e., certificates, permits, licenses, etc.) before operating the equipment. The owner shall obtain operating certificates, permits, etc. required by the jurisdiction prior to commencing operation. I-5240 INSPECTION All piping shall be inspected after installation and prior to commencing operation. I-5250 OPERATING PERMIT The owner shall obtain any operating permit(s) required by the jurisdiction, prior to placing the piping into service. I-5320 FLANGES AND OTHER NON-WELDED JOINTS The layout of the piping shall take into consideration the need to maintain piping joints and required access for maintenance and inspection. I-5330 VALVES Consideration should be given to the appropriate location and orientation of valves necessary for safe operation and isolation of the piping. I-5400 MATERIALS All materials for piping and its appurtenances shall comply with the requirements of the code of construction. I-5500 HANGERS AND SUPPORTS Support of piping shall consider loads imposed on equipment or existing piping to which it is attached. Non-piping attachments such as ladders and walkways, equipment supports, temporary supports, structural supports, etc. shall not be connected to the piping unless such loads have 430 APPENDIX I — INSTALLATION REQUIREMENTS been considered in the design of the piping and its supports. Design of hangers and supports for piping shall consider loads imposed by pressure testing. The installer shall remove pins from non-rigid hangers, seal plugs from hydraulic snubbers and temporary supports used for installation prior to placing the piping in service. I-5600 PROTECTION AND CLEANING The installer shall exercise care during installation to prevent loose weld material, welding rods, small tools and miscellaneous scrap metal from getting into the piping. The installer shall inspect, and where necessary clean, the interior of the piping and its appurtenances where possible prior to making the final closures for the presence of foreign debris. I-5700 WELDING AND BRAZING The installer should consider the impact of performing any preheating, welding, brazing or postweld heat treatment on valves, instrumentation or other heat sensitive equipment and, where appropriate, review the equipment manufacturer ’s recommended installation procedures prior to performing the work. I-5800 PRESSURE RELIEF DEVICES When required by the original code of construction, piping shall be protected by pressure relief devices in accordance with the following requirements. I-5810 DEVICE REQUIREMENTS a. Pressure relief devices are to be manufactured in accordance with a national or international standard and be certified 431 for capacity (or resistance to flow for rupture disc devices) by the National Board. 1. In certain cases piping standards permit the use of regulators which may include integral pressure relief valves to limit the pressure in a piping system. In this case, capacity certification of the pressure relief valve is not required. b. Dead weight or weighted lever pressure relief devices shall not be used. c. Pressure relief devices shall be selected (i.e., material, pressure, etc.) and installed such that their proper functioning will not be hindered by the nature of the piping system’s contents. I-5820 NUMBER OF DEVICES At least one pressure relief device shall be provided for protection of a piping system. A pressure relief device installed on a pressure vessel or other component connected to the piping system may be used to meet this requirement. Portions of piping systems with different maximum allowable working pressures shall have a pressure relief device to protect each portion separately. I-5830 LOCATION The pressure relief device may be installed at any location in the system provided the pressure in any portion of the system cannot exceed the maximum allowable working pressure. Pressure drop to the pressure relief device under flowing conditions shall be considered when determining pressure relief device location. The device shall be in communication with the piping system it is protecting at all times. NATIONAL BOARD INSPECTION CODE I-5840 CAPACITY a. The pressure relief device(s) shall have sufficient capacity to assure that the piping is not exposed to pressures greater than that specified in the original code of construction. b. When a non-reclosing device is installed between a pressure relief valve and the pipe, the reduction in capacity due to installation of the non-reclosing device shall be determined in accordance with the code of construction by use of a National Board certified Combination Capacity Factor (CCF). For rupture disks, if a certified combination capacity factor is not available, the capacity of the pressure relief valve shall be multiplied by 0.9 and this valve used as the capacity of the combination installation. c. The owner shall document the basis for selection of the pressure relief devices used, including capacity, and have such calculations available for review by the jurisdiction. I-5850 SET PRESSURE a. When a single pressure relief device is used, the set pressure marked on the device shall not exceed the maximum allowable working pressure, except when allowed by the original code of construction. b. When more than one pressure relief device is provided to obtain the required capacity, only one pressure relief device set pressure needs to be at the maximum allowable working pressure. The set pressures of the additional pressure relief devices shall be such that the pressure cannot exceed the overpressure permitted by the code of construction. I-5860 INSTALLATION AND DISCHARGE PIPING REQUIREMENTS a. The opening through all pipe and fitting between a piping system and its pressure relief device shall have at least the area of the pressure relief device inlet. The characteristics of this upstream system shall be such that the pressure drop will not reduce the relieving capacity below that required or adversely affect the operation of the pressure relief device. b A non-reclosing device installed between a piping system and a pressure relief valve shall meet the requirements of I-5860(a). c. The opening in the pipe shall be designed to provide unobstructed flow between the pipe and its pressure relief device. d. When two or more required pressure relief devices are placed on the connection, the inlet cross sectional area of this connection shall be sized either to avoid restricting flow to the pressure relief devices or made at least equal to the combined inlet areas of the pressure relief devices connected to it. The flow characteristics of the upstream system shall satisfy the requirements of I-5860(a). e. There shall be no intervening stop valves between the piping system and its pressure relief device(s), or between the pressure relief device(s) and the point of discharge except under the following conditions: 1. When these stop valves are so constructed or positively controlled that the closing of the maximum number 432 APPENDIX I — INSTALLATION REQUIREMENTS of block valves at one time will not reduce the pressure relieving capacity below the required relieving capacity; or, 2. Upon specific acceptance of the jurisdiction, when necessary for the continuous operation of processing equipment of such a complex nature that shutdown of any part is not feasible, a full area stop valve between a piping system and its pressure relief device may be provided for inspection and repair purposes only. This stop valve shall be arranged so that it can be locked or sealed open, and it shall not be closed except by an authorized person who shall remain stationed there during that period of operation while the valve remains closed. The valve shall be locked or sealed in the open position before the authorized person leaves the station. 3. A full area stop valve may be placed on the discharge side of a pressure relief device when its discharge is connected to a common header for pressure relief devices to prevent discharges from these other devices from flowing back to the first device during inspection and repair. This stop valve shall be arranged so that it can be locked or sealed open, and it shall not be closed except by an authorized person who shall remain stationed there during that period of operation while the valve remains closed. The valve shall be locked or sealed in the open position before the authorized person leaves the station. This valve shall only be used when a stop valve on the inlet side of the pressure relief device is first closed. 433 4. A piping system where the pressure originates from an outside source may have a stop valve between the system and the pressure relief device, and this valve need not be sealed open, provided it also closes off that vessel from the source of pressure. f. Pressure relief device discharges shall be arranged such that they are not a hazard to personnel or other equipment and when necessary, lead to a safe location for disposal of fluids being relieved. g. Discharge lines from pressure relief devices shall be designed to facilitate drainage or be fitted with drains to prevent liquid from collecting in the discharge side of a pressure relief device. The size of discharge lines shall be such that any pressure which may exist or develop will not reduce the relieving capacity of the pressure relief device, or adversely affect the operation of the pressure relief device. h. Pressure relief devices shall be installed so they are accessible for inspection, repair or replacement. I-5900 EXAMINATION, INSPECTION AND TESTING THE OWNER SHALL ENSURE THAT ALL EXAMINATIONS, INSPECTIONS AND TESTS REQUIRED BY THE CODE OF CONSTRUCTION HAVE BEEN PERFORMED PRIOR TO OPERATION. NATIONAL BOARD INSPECTION CODE 434 Guide to Jurisdictions for Authorization of Owners-Users to Make Adjustments to Pressure Relief Valves Appendix J 435 NATIONAL BOARD INSPECTION CODE APPENDIX J — GUIDE TO JURISDICTIONS FOR AUTHORIZATION OF OWNERS-USERS TO MAKE ADJUSTMENTS TO PRESSURE RELIEF VALVES J-1000 GENERAL J-1020 It is recommended that before an owner-user or their designees be authorized to make adjustments as defined in paragraph RE-1023, the following requirements should be met: J-1010 Each user shall document the evaluation and acceptance of an employee’s or designee’s qualifications. J-1020 TRAINING The user shall establish a documented inhouse training program. This program shall establish training objectives and provide a method of evaluating the training effectiveness. As a minimum, training objectives for knowledge level shall include: a. Applicable ASME Code and NBIC requirements; b. Responsibilities within the organization’s quality system; c. Knowledge of the technical aspects and mechanical skills for making set pressure and/or blowdown adjustments to pressure relief valves; d. Knowledge of the technical aspects and mechanical skills for marking of pressure relief valve adjustments. If the user established a designee, the designee shall establish a training program and make their documentation available to the user and the jurisdictional authority. DOCUMENTATION QUALITY SYSTEM A written quality system shall be established by either the user or the designee with a written description available to the jurisdictional authority. The written description shall include at a minimum: a. Calibration of Test Equipment: This shall describe the method of periodic calibration of instruments and pressure gages. Documentation of these calibrations should include the standard used and the results. All calibration standards shall be calibrated against the equipment having valid relationships to nationally recognized standards. b. Valve Testing, Setting and Sealing: This system shall include provisions that each valve shall be tested, set and all external adjustments sealed according to the requirements of the applicable ASME Code Section and NBIC RE-1023. c. Valve Marking: An effective marking system shall be established to ensure proper marking of the metal tag required by RE-1023. The written quality system shall include a description of drawing of the metal tag. 436 APPENDIX J — GUIDE TO JURISDICTIONS FOR AUTHORIZATION OF OWNERS-USERS TO MAKE ADJUSTMENTS TO PRESSURE RELIEF VALVES J-1040 EXTERNAL ADJUSTMENTS Only external adjustments to restore the required set pressure and/or performance of a pressure relief valve shall be made under the provisions of RE-1023. J-1050 REPAIRS If disassembly, change of set pressure, or additional repairs are necessary, the valve shall be repaired by an organization which meets the requirements of the NBIC. 437 NATIONAL BOARD INSPECTION CODE 438 Inspection, Repairs, and Alterations for Yankee Dryers Appendix K 439 NATIONAL BOARD INSPECTION CODE APPENDIX K — INSPECTION, REPAIR, AND ALTERATION OF YANKEE DRYERS K-1000 K-1010 ternal and external shell surfaces. The dryer has an internal system to remove steam and condensate. These vessels can weigh up to 220 tons (200 tonnes). INSPECTION OF YANKEE DRYERS (ROTATING CASTIRON PRESSURE VESSELS) WITH FINISHED SHELL OUTER SURFACES SCOPE This part describes guidelines for the inservice inspection of a Yankee dryer. A Yankee dryer is a rotating steam-pressurized cylindrical vessel commonly used in the paper industry, and is made of cast iron, finished to a high surface quality and characterized by a center shaft connecting the heads. “Yankee dryers” are primarily used in the production of tissue-type paper products. When used to produce machine glazed (MG) paper, the dryer is termed an MG cylinder. A wet paper web is pressed onto the finished dryer surface using one or two pressure (pressing) rolls. Paper is dried through a combination of mechanical dewatering by the pressure roll(s); thermal drying by the pressurized Yankee dryer and a steam heated or fuel fired hood. After drying, the paper web is removed from the dryer. The dryer is typically manufactured in a range of outside diameters from eight (8) to twenty three (23) feet (2.4 m to 7 m), widths from eight (8) to twenty eight (28) feet (2.4 m to 8.5 m), pressurized and heated with steam up to 160 psi (1100 kPa), and rotated at speeds up to 7000 ft/min (2135 m/min). Typical pressure roll loads against the Yankee dryer are up to 600 pounds per lineal inch (105 kN/m). A thermal load results from the drying process due to difference in temperature between in- The typical Yankee dryer is an assembly of several large castings. The shell is normally a gray iron casting, in accordance with ASME designation SA-278. Shells internally may be smooth bore or ribbed. Heads, center shafts and journals may be gray cast iron, ductile cast iron, or steel. K-1020 ASSESSMENT OF INSTALLATION The Inspector verifies that the owner or user is properly controlling the operating conditions of the dryer. The Inspector does this by reviewing the owner’s comprehensive assessments of the complete installation, operating environment, maintenance, and operating history. The dryer is subjected to a variety of loads over its life. Some of the loads exist individually, while others are combined. Consideration of all the loads that can exist on a Yankee dryer is required to determine the maximum allowable operating parameters. There are four loads that combine during normal operation to create the maximum operating stresses, usually on the outside surface of the shell at the axial center line. These are: a. Pressure load due to internal steam pressure; b. Inertial load due to dryer rotation; 440 APPENDIX K — INSPECTION, REPAIRS, AND ALTERATIONS FOR YANKEE DRYERS c. Thermal gradient load due to the drying of the web; d. Pressure roll load (line or nip load)21 due to pressing the wet web onto the dryer. Steam pressure, inertial, and thermal gradient loads impose steady-state stresses. These stresses typically change when the dryer shell thickness (effective thickness for ribbed dryers) is reduced to restore a paper-making surface, the grade of tissue is changed or speed of the dryer is changed. The pressure roll(s) load imposes an alternating stress on the shell face. The resulting maximum stress is dependent on the magnitude of the alternating and steady-state stresses. Section VIII, Div. 1, of the ASME Code only provides specific requirements for the analysis of pressure loads. Although the Code requires analysis of other loads, no specific guidance for thermal, inertial, or pressure roll loads is provided. Hence, additional criteria must be applied by the manufacturer to account for all the steady-state and alternating stresses. To maintain product quality, the dryer surface is periodically refurbished by grinding. This results in shell thickness reduction. Therefore, the manufacturer does not provide a single set of maximum allowable operating parameters relating steam pressure, rotational speed, and pressure roll load for a single design shell thickness. The manufacturer, or another qualified source acceptable to the Inspector, instead provides a series of curves that graphically defines these maximum allowable operating parameters across a range of shell thicknesses. This document is known as the “De-rate Curve.” See Figure K-1020. 21 In addition to the loads on the dryer due to normal operation, other non-standard load events can occur. These non-standard load events should be recorded in an operation or maintenance log. Examples of non-standard load events include: a. Excessive thermal load due to local or global heating rate during warm-up; b. Excessive thermal load due to local or global cooling rate during shut-down; c. Excessive thermal load due to inappropriate use or malfunctioning auxiliary heating devices causing localized heating; d. Excessive thermal load due to the misapplication or uncontrolled application of water or other fluids for production, cleaning or fire fighting; e. Impact load. If non-standard load events have occurred, then the Inspector should ensure that an appropriate assessment of the structural integrity on the dryer has been performed. K-1030 CAUSES OF DETERIORATION AND DAMAGE Three types of deterioration or damage typically encountered in Yankee dryers are local thinning, cracking, and corrosion. Many times these mechanisms are interrelated, one being the precursor of another. Pressure roll load, line load, and nip load are terms that are used interchangeably to refer to the interaction between the pressure roll(s) and the Yankee dryer. It is called “nip” load because the pressure roll is rubber-covered and is pressed up against the Yankee with enough force to create a nip (or pinch) that forces the paper into line contact between the rolls and provides some mechanical dewatering. The paper then sticks onto the Yankee surface and follows the Yankee dryer for thermal dewatering by the steam-heated Yankee surface. This “nip load” is called a “line load” because the units are load (force) per length of line contact. The units are pounds per linear inch (PLI) and kiloNewtons per meter (kN/m). 441 NATIONAL BOARD INSPECTION CODE K-1031 LOCAL THINNING Internally, a Local Thin Area (LTA) can occur on the pressure-retaining surfaces due to steam and condensate erosion, mechanical wear, and impact, and removal of material flaws. These assume features ranging from broad shallow areas washed-out by erosion, to more groove-like flaws, including gouges and indentations from contacting metal parts. Externally, the process is typically one of wearcorrosion in circumferential bands. Except on the shell edges, local thinning never achieves significant depth because the papermaking process will tolerate only the smallest departure from surface contour. On the shell edges, beyond the papermaking surface, wear-corrosion may advance to comparatively greater depths. However, the stresses are far less in this area than under the papermaking surface, so the wear is inconsequential in considerations of load-carrying ability. Only in the instance of steam leakage between flanges, has the resultant local thinning ever been implicated in Yankee failure. Steam leakage is detrimental to the long-term structural integrity of the vessel, in that the escaping steam, under high velocity, erodes ever-widening paths in the cast-iron surfaces over which it passes, thinning the cross section. Steam cutting of connecting bolts is another possible outcome. Either result FIGURE K-1020 Approve reorganization and update of Part RB to be incorporated into Draft2003 Addendum which will result �� 442 APPENDIX K — INSPECTION, REPAIRS, AND ALTERATIONS FOR YANKEE DRYERS reduces load-carrying capacity of the part. A safety hazard can also be created for operating personnel, who may be burned by the high velocity steam jets. a. Interface leakage, including joints and bolted connections 1. Joint Interface Corrosion Jacking forces, which develop from the expansion of corrosion products between head-to-shell flanges, cause flange separation and create leakage paths between the flanges and/or through the bolt holes. K-1032 CRACKING Cracks in cast-iron parts are problematic because of the relatively low fracture toughness compared with standard, more ductile pressure vessel materials and because strengthening repair through welding is prohibited. Furthermore, Yankee dryers are subject to both low and high-cycle fatigue loading. Consequently, considerable emphasis is placed upon quality inspection for and timely remediation of cracks, the central causes of which (in Yankee dryers) are: a. Through joints and bolted connections 2. Insufficient Joint Clamping Force Through inadequate design, improper assembly, loss of washer/gasket, or stress corrosion cracking of connecting bolts, the clamping force between mating flanges is insufficient to retain internal pressure. 1. Joint Interface Corrosion Jacking forces, which develop from the expansion of corrosion products between head-to-shell flanges, cause flange separation and create leakage paths between the flanges and/or through the bolt holes. 3. Washer/Gasket Functional Loss Deterioration, caused by corrosion or expulsion, provides a path for escaping steam and condensate. 2. Insufficient Joint Clamping Force Through inadequate design, improper assembly, loss of washer/gasket, or stress corrosion cracking of connecting bolts, the clamping force between mating flanges is insufficient to retain internal pressure. 4. Flange Machining Variation Variations in surface contour of flange faces may create leakage paths. 5. Through-Wall Leakage Cast iron inherently exhibits shrinkage porosity. Where porosity linkages occur between internal and external surfaces, a path for steam leakage is made available. Such leakage is largely an operational issue, as holes are formed in the paper product, demanding expedient attention. 3. Washer/Gasket Functional Loss Deterioration, caused by corrosion or expulsion, provides a path for escaping steam and condensate. 4. Flange Machining Variation Variations in surface contour of flange faces may create leakage paths. b. Through-Wall Leakage Cast iron inherently exhibits shrinkage porosity. Where porosity linkages occur between internal and external surfaces, a path for steam leakage is made available. Such leakage in the shell is largely an operational issue, as holes are formed in the paper product, demanding expedient attention. 443 NATIONAL BOARD INSPECTION CODE c. Impact from Objects Passing Through the Yankee/Pressure Roll Nip Because of cast iron’s low fracture toughness, it is especially intolerant of local, high impact loads. d. Stress Magnification Around Drilled Holes Surface defects, caused by porosity and indentations, are frequently repaired with driven plugs, having some level of interference fit. Pumping ports, threaded for a tapered pipe fitting, are often installed as a standard Yankee design feature for sealant injection into flange interfaces. When installed, both produce an area of increased stress, local to the hole’s edge. In the case of driven plugs this stress can be exaggerated by excessive interference fits and by closely-grouped or over-lapping plugs. Over-torque of threaded, tapered plugs can cause cracks to develop at the periphery of the hole. e. Thermal Stress and/or Microstructural Change from Excessive Local Heating and Cooling Transient thermal stresses are usually the highest encountered by a Yankee dryer. Temperature differential through and between parts can be of such magnitude as to exceed the strength of the material. When abnormal thermal loads occur, non-destructive examination is crucial to ensure the vessel’s fitness-for-service. Microstructural change and transient thermal stresses, sufficiently high to cause cracking in Yankee dryers, have resulted, or could result, from: • • • • • • bearing failure rapid warm-up excessive steam temperature heat from fires application of water sprays to fight fires and remove paper jams continuous and excessive local cooling from water sprays • • • f. operating heating or cooling systems while the Yankee is stationary; e.g., high temperature air impingement hoods, infra-red heating devices, coating showers welding and electrical arcs on castiron parts excessive local temperature due to improper thermal spray application Joint Interface Corrosion The products of corrosion occupy a larger volume than the base metal. The forces created by this expansion are sufficient to cause cracking in cast-iron flanges. Without remediation, expansion will continue until failure occurs. Corrosion products form in the presence of moisture in the crevice created between flanges, wherever the clamping force is insufficient to maintain contact between the mating surfaces. g. Stress-Corrosion Cracking of Structural Bolts Stress-corrosion cracking (SCC) is the result of the combination of a corroding agent, material sensitivity, tensile stress, and temperature. At stress levels sufficiently high to induce SCC in the presence of a corrosive medium, attack proceeds along or through grain boundaries perpendicular to the direction of maximum tensile stress. Cracking can initiate with little or no evidence of general corrosion. K-1033 CORROSION Corrosion culminates with a failure in component functionality by diminishing loadcarrying capacity or by generating forces beyond the material’s strength. In addition to SCC, corrosion-jacking (head to shell joint), wear-corrosion, and deterioration of washers described above, oxygen pitting and general 444 APPENDIX K — INSPECTION, REPAIRS, AND ALTERATIONS FOR YANKEE DRYERS corrosion wastage need to be considered as potential failure causes. These latter two corrosion conditions are the result of inadequate boiler water treatment. Oxygen pitting has been encountered, but rarely. K-1040 INSPECTIONS Yankee dryers should be inspected on a routine-periodic basis. However, as a minimum, the Yankee dryer should be inspected internally and externally at least one time every two years. As appropriate, the following items should be included: • • • • • • • • head-to-shell joint shell out-of-roundness shell centerline thickness tilt of head flange integrity and security of internal parts spigot fit of flanged joints (head-to-shell, head-to-journal) integrity of structural bolts and studs previously identified areas of deterioration and damage Typical nondestructive examination methods may be employed to determine indication length, depth, and orientation (sizing) of discontinuities in Yankee dryers. Magnetic particle, specifically the wet fluorescent method, and dye penetrant methods are applicable in the evaluation of surface-breaking indications. Ultrasonic testing is the standard method for evaluation of surface-breaking and embedded indications. Radiographic methods are useful in the evaluation of embedded indications. Acoustic Emission Testing can be used to locate and determine if a linear indication is active; i.e., propagating crack. Metallographic analysis is useful in differentiating between original casting discontinuities and cracks. When nondestructive testing produces an indication, the indication is subject to interpretation as false, relevant, or non-relevant. If it has been interpreted as relevant, the necessary subsequent evaluation will result in a decision to accept, repair, replace, monitor, or adjust the maximum allowable operating parameters. K-1060 PRESSURE TESTING When a non-standard load event occurs, or a material non-conformity is noted, an inspection should be performed to assess fitness for continued service. This inspection may involve testing methods not typically used in routine inspections and may also involve removal of material samples for destructive testing. Hydrostatic testing is not recommended due to the weight of water required to fill the large internal volume of a Yankee dryer. The additional weight can lead to support structure (floor) overload, deformation of the high tolerance dryer surface and internal contamination. Hydrostatic testing requires special support of the Yankee dryer shell to minimize damage to the journals and bearings. K-1050 When pressure testing is desired to evaluate forms of deterioration, acoustic emission testing, with steam or air, is recommended. Typically, the test pressure used is the operating pressure. NONDESTRUCTIVE EXAMINATION Nondestructive examination (NDE) methods shall be implemented by individuals qualified and experienced with the material to be tested using written NDE procedures. For Yankee dryers, cast iron knowledge and experience are essential. 445 NATIONAL BOARD INSPECTION CODE K-2000 GENERAL REQUIREMENTS FOR REPAIRS AND ALTERATIONS TO YANKEE DRYERS K-2010 SCOPE K-2040 This section provides additional requirements for repairs and alterations to Yankee dryer pressure-retaining components and shall be used in conjunction with K-1000. K-2020 REPLACEMENT PARTS Yankee dryer replacement pressure-retaining parts shall be fabricated in accordance with the manufacturer’s design and the original code of construction. Yankee dryer pressureretaining parts may include: • • • • • • shell heads center shaft, stay, or trunnion stay bars structural bolting journals Replacement of non-pressure-retaining parts, when different from the manufacturer’s design, shall be evaluated for any possible effect on the pressure-retaining parts. K-2030 EXAMINATIONS AND TEST METHODS In addition to the requirements of RC-2051 and RC-3031, the following are recommended: a. Acoustic emission testing b. Metallographic examination when thermal damage is suspected due to operational or repair activities, microstructure analysis. DETERMINATION OF ALLOWABLE OPERATING PARAMETERS A Yankee dryer is designed and intended to have its shell thickness reduced over the life of the vessel through routine wear and grinding. The Yankee dryer shell is ground on the outside surface to restore the quality or shape of the papermaking surface, essential to the manufacturing of tissue or other paper products. Design documentation is required which dictates the maximum allowable operating parameters as shell thickness is reduced. Calculations, used to determine those parameters, are in accordance with ASME Code requirements for primary membrane stress and design criteria based upon other relevant stress categories; e.g., fatigue and maximum principal stress. Calculation of these parameters requires that the respective stresses, resulting from the imposed loads, be compared to the appropriate material strength properties. Hence, knowledge of the applied stresses in the shell and the tensile and fatigue properties of the material are essential. Yankee dryers are subjected to a variety of loads that create several categories of stress. Yankee dryers are designed such that the stress of greatest concern typically occurs on the outside surface at the axial centerline of the shell. a. Steam Pressure Load – The internal steam pressure is one of the principal design loads applied to the Yankee dryer. The steam pressure expands the shell radially, causing a predominately circumferential membrane tensile stress. Because the shell is constrained radially by the heads at either end of the shell, the steam pressure also causes a primary bending stress in the vicinity of the head-to-shell joint. The ends 446 APPENDIX K — INSPECTION, REPAIRS, AND ALTERATIONS FOR YANKEE DRYERS of the shell are in tension on the inside and compression on the outside due to the steam pressure. The steam pressure also causes a bending stress in the heads. This stress is greatest at the centerline of the shell. The load of the pressure roll deflects the shell radially inward causing a circumferential compressive stress on the outside surface and a tensile stress on the inside. Because the shell has been deflected inward at the pressure roll nip, it bulges outward about 30 degrees on each side of the nip. The outward bulge causes a tensile stress on the outside shell surface at that location and a corresponding compressive stress on the inside. Since the shell is passing under the pressure roll, its surface is subjected to an alternating load every revolution. b. Inertia Load – The rotation of the Yankee dryer causes a circumferential membrane stress in the shell similar to that caused by the steam pressure load. This stress is included in the design of the shell and increases with dryer diameter and speed. c. Thermal Gradient Load – The wet sheet, applied to the shell, causes the outside surface to cool and creates a thermal gradient through the shell wall. This thermal gradient results in the outside surface being in tension and the inside surface in compression. With this cooling, the average shell temperature is less than the head temperature, which creates bending stresses on the ends of the shell and in the heads. The ends of the shell are in tension on the outside and compression on the inside. Other thermal loading also occurs on a Yankee. The use of full width showers for a variety of papermaking purposes affects the shell similar to a wet sheet. The use of edge sprays produce high bending stress in the ends of the shell due to the mechanical restraint of the heads. Warm-up, cool-down, hot air impingement from the hood, moisture profiling devices, fire fighting, and wash-up can all produce non-uniform thermal stresses in the pressure containing parts of the Yankee dryer. Heating or cooling different portions of the Yankee dryer at different rates causes these non-uniform stresses. d. Line Load – The line load from the contacting pressure roll(s), results in an alternating, high cycle, bending stress in the shell. K-2041 ASME CODE PRIMARY MEMBRANE STRESS CRITERION Yankee dryers are typically designed and fabricated in accordance with Section VIII, Div. 1, of the ASME Code. The maximum allowable stress for cast iron is specified in UCI-23 of the ASME Code. Section VIII, Div. 1, requires design stresses to be calculated such that any combination of loading expected to occur simultaneously during normal operation of the Yankee dryer will not result in a general primary stress exceeding the maximum allowable stress value of the material. In the ASME Code, the combination of loading resulting in the primary membrane stress is interpreted to be composed only of the circumferential stress from steam pressure. Sometimes, the stress from the inertial loading is included in this consideration. In Section VIII, Div. 1, it is very important to note that no formulas are given for determining the stresses from thermal gradient loads, inertial loads, and pressure roll nip loads. Hence, additional criteria need to be incor- 447 NATIONAL BOARD INSPECTION CODE porated to establish the maximum allowable operating parameters of the Yankee dryer. As the thickness of the shell is reduced, one or more of these criteria will control the various operating parameters. Two such additional criteria are based upon the maximum principal and fatigue stress. papermaking surface. The papermaking surface degrades due to wear, corrosion, and local thinning. As the shell thickness is reduced, the maximum allowable operating parameters are adjusted. Adjustment of the maximum allowable operating parameters requires accurate shell thickness measurements. a. Maximum Principal Stress Criterion The maximum principal stress in a Yankee shell is the sum of the stresses that are simultaneously applied to the shell, and is always aligned in the circumferential direction. The purpose of this criterion is to recognize the paper making application of the Yankee dryer and to prevent catastrophic failure, by including all stresses. The ASME Code does not provide specific formulas for the full array of dryer stresses encountered in a paper making application. Over the life of the Yankee dryer, the adjustment of the maximum allowable operating parameters will require that the original design pressure and/or the pressure roll line load be reduced. After the maximum allowable operating parameters are adjusted per the De-rate Curve, the appropriate load limiting devices are reset (e.g., steam safety relief valve, line load limiting device). b. Fatigue Stress Criterion Under normal operation, the stresses due to the steam pressure, inertial and thermal gradient loads are considered to be steady-state stresses. When acting simultaneously, the sum of these stresses must be calculated and combined with the alternating stress due to the pressure roll line load. A fatigue stress criterion limits the alternating stress at a given mean stress using fatigue failure criteria described by the Goodman or Smith Diagram. The purpose of this limitation is to prevent crack initiation in the outside wall due to the combination of stresses. K-2042 ADJUSTING THE MAXIMUM ALLOWABLE OPERATING PARAMETERS OF THE YANKEE DRYER DUE TO A REDUCTION IN SHELL THICKNESS FROM GRINDING OR MACHINING The outside surface of the Yankee dryer shell is routinely ground to restore the quality of the K-2043 DOCUMENTATION OF SHELL THICKNESS AND ADJUSTED MAXIMUM ALLOWABLE OPERATING PARAMETERS Yankee dryers are designed and intended to have the shell thickness reduced over the life of the vessel as a result of routine wear and grinding. Yankee shell grinding is routinely performed to restore the quality or shape of the papermaking surface. Design documentation, a De-rate Curve, is required, which dictates the maximum allowable operating parameters, based on imposed loads over a range of shell thickness. The documentation shall be obtained from the original dryer manufacturer or from another qualified source acceptable to the Inspector. Yankee dryer shell grinding requires accurate shell thickness measurements in conjunction with the De-rate Curve in order to set loadlimiting devices. The resulting shell thickness and maximum allowable operating parameters after grinding shall be documented, and the Inspector notified that load-limiting device settings have changed. 448 APPENDIX K — INSPECTION, REPAIRS, AND ALTERATIONS FOR YANKEE DRYERS K-2050 STAMPING Stamping is not required for repairs which do not affect the pressure-retaining capability of the Yankee shell, as indicated on the De-rate Curve, or other pressure-retaining parts as indicated on the original Manufacturer’s Data Report. Stamping is required for repairs which do affect the pressure-retaining capability of the Yankee shell, as indicated on the De-rate Curve, or other pressure-retaining parts as indicated on the original Manufacturer’s Data Report. Structural deterioration or damage caused by corrosion, thinning, or cracking shall not be repaired until their extent has been determined by suitable nondestructive examination. The user shall have a plan covering the scope of the repair. The plan shall ensure that the work involved is compatible with the original design specification and good engineering practices. All repair work shall be documented. K-3030 Stamping is required for alterations as listed in K-4020. Stamping, when required, shall meet the requirements for stamping in RC-3040. The location of stamping shall be described in the remarks section of Form R-2. K-3000 YANKEE DRYER REPAIR METHODS K-3010 SCOPE All repair procedures, shall be acceptable to the Inspector, and when verified by the owner-user to not affect pressure-retaining capability of the Yankee dryer, do not require stamping or nameplate attachment. Examples of repairs are: Grinding and machining: • • This section provides additional requirements for repair methods to Yankee dryer pressureretaining components and shall be used in conjunction with K-1000 and K-2000. K-3020 PROCEDURES WHICH DO NOT REQUIRE STAMPING OR NAMEPLATE ATTACHMENT REPAIR GUIDE FOR YANKEE DRYERS Welding or brazing shall not be used on any Yankee dryer pressure-retaining component manufactured from cast iron. The Manufacturer’s Data Report shall be carefully reviewed to determine the material of construction of each Yankee Dryer component such as shell, heads, and journals. • • • • • • removal of shell overhung flange removing bolt-stop ring for test specimens head/Shell joint corrosion removal journal grinding shell surface grinding (crowning) crack removal head flange OD reduction back spot facing of flange surfaces (head, shell, journal) Metallizing (full face, spot, edge): • • applying a metallized coating grinding of a metallized coating Epoxy filling of surface imperfection Installation of spoiler bars 449 NATIONAL BOARD INSPECTION CODE Maintain/repair/ replace internal condensate removal system A04 Driven plug repair when completed as described in K-3053. K-3050 DAMAGE REPAIR K-3051 REPAIR OF LOCAL THINNING A Local Thin Area (LTA) may develop in a pressure-retaining part or may result from the original casting process. Inservice thin areas may result from mechanical wear, erosioncorrosion caused by steam and condensate flow, corrosion, impact damage, or grinding for the removal of material flaws. Evaluation of thinning for repair shall consider the unique design and loading characteristics of the Yankee dryer. Local thin areas are often analyzed as specific cases by the finite element method. a. When a LTA is evaluated by finite element method, analysis should consider the location of the thin area and account for strength provided by the vessel centershaft and heads in addition to the strength provided by the shell alone. Such structural analysis should consider all relevant loads to ensure safe operation of the shell according to the De-rate Curve, or other pressure-retaining parts as indicated on the original Manufacturer’s Data Report. b. Following evaluation and determination of maximum allowable operating parameters, a LTA can be coated or filled to prevent further wear or deterioration. Grooves and gouges should always be lightly ground to remove sharp notches and edges. Welding or brazing repairs are NOT permitted on cast-iron pressureretaining components. c. Where the LTA is of sufficient size to cause a reduction in maximum allowable operating parameters according to the De-rate Curve, an R-2 Form shall be submitted. d. Depending upon the cause of the LTA, further monitoring may be necessary to ensure deterioration has been arrested. e. Inspection data, including all thickness readings and corresponding locations used to determine the minimum and average thicknesses, and the accompanying stress analysis, should be included in the documentation and retained for the life of the vessel. K-3052 TREATMENT OF CRACK-LIKE FLAWS Crack-like flaws are planar flaws which are predominantly characterized by a length and depth with a sharp root radius. They may either be embedded or surface breaking. In some cases it may be advisable to treat volumetric flaws, such as aligned porosity, inclusions, and laps, as planar flaws, particularly when such volumetric flaws may contain microcracks at the root. a. Knowledge of local stress level and classification, and of flaw origin, type, size, location, and angle relative to the principal stress direction is essential in making determinations regarding remediation. It is also important to know whether the crack is active. Acoustic Emissions Testing can be used to determine if the crack is active. Various other methods of nondestructive examination may be employed to determine crack length and depth. Ultrasonics is the recommend

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