Document Title:
Flange Management Procedure
COPI Doc No.:
ID-N-SB-LL0-PRO-ST-00-0001
Originator:
COPI Group Owner:
Area:
Location:
System:
Document Type:
Discipline / Subdiscipline:
Old COPI Document No.:
PT. Wijaya Karya (Persero). Tbk
Engineering-O
Suban
Suban Station
General
Flange Management Procedure
Piping / Piping
0B
IFA
12 Okt 2012
Issued for Approval
GP
ZR
AGN
0A
IFC
18 June 2012
Issued for Comment
AR
FAD
AGN
Rev
Status
Issue Date
Reason for Issue
Prepar
ed
Check
ed
MER / HS
MER / HS
OEE / Project
Approval
Approvals
Printed initials in the approval boxes confirm that the document has been signed.
The originals are held within Document Management.
AIB
AIB
Unit Owner
Procedure/Work Instruction/Job Note:
Flange Management Proceure
ConocoPhillips Indonesia
ID-N-SB-LL0-PRO-ST-00-0001
Page 2 of 32
Revision Sheet
ConocoPhillips Indonesia Inc. Ltd
REVISION
DATE
0A
18 June 2012
0B
12 Okt 2012
DESCRIPTION OF CHANGE
Issued for Comment
Refer to COPI Specification or Procedure ID-G-BU-00000-0000001548 In-Service Flange Integrity Guidline.
Procedure/Work Instruction/Job Note:
Flange Management Proceure
ConocoPhillips Indonesia
ID-N-SB-LL0-PRO-ST-00-0001
Page 3 of 32
Table of Contents
Table of Contents ......................................................................................................................................................3
1
Introduction ..........................................................................................................................................4
1.1
Purpose ..................................................................................................................................................4
1.2
Scope......................................................................................................................................................4
1.3
References .............................................................................................................................................4
2
Definition ...............................................................................................................................................5
3
Flange Management Requirement and Procedure .....................................................................5
3.1
Flange Joints Disturbance Procedure ................................................................................................5
3.1.1 Reference Documentation ...................................................................................................................5
3.1.2 Breaking Flange Joints .........................................................................................................................5
3.1.3 Making Joints .........................................................................................................................................6
3.1.4 Tagging Procedure ................................................................................................................................ 6
3.2
Flange General Requirements ............................................................................................................9
3.2.1 Bolting .....................................................................................................................................................9
3.2.2 Thread Lubricants and Preservatives.................................................................................................9
3.2.3 Flange Faces ...................................................................................................................................... 10
3.2.4 Gaskets ............................................................................................................................................... 10
3.2.5 Insulation Gasket Sets and Specialty Gasket ................................................................................ 10
3.3
Tightening ........................................................................................................................................... 11
3.3.1 Tightening Methods ............................................................................................................................11
3.4
Hot Bolting and Preventative Bolting ............................................................................................... 13
3.4.1 Hot Bolting Requirement ................................................................................................................... 13
3.4.2 Hot bolting procedure ......................................................................................................................... 14
3.4.3 Preventative Maintenance Bolting ................................................................................................... 14
3.4.4 Preventative Maintenance Bolting Procedure ................................................................................ 15
4
Flange System Records ................................................................................................................. 15
5
Responsibilities ................................................................................................................................... 15
Procedure/Work Instruction/Job Note:
Flange Management Proceure
ConocoPhillips Indonesia
ID-N-SB-LL0-PRO-ST-00-0001
Page 4 of 32
1 Introduction
Widely used in piping installation flange connection type that must be properly installed according to
existing standard. It is necessary to be a procedure that can be used as a reference for instating the
flange connection
1.1
Purpose
This document is intended as a guide on how to install flanged joints in service for plant and facilities. It
provides a framework to achieve this based on working with correctly designed joints.
This document also provides guideline when works disturb a flanged joint (repair/replacement) to ensure
integrity and quality requirements are met upon reinstatement.
In order to avoid failure, it is very important that the relevant specifications for materials and components
are adhered to in full.
1.2
Scope
This guideline shall be applied within COPI facility when works disturb flange joints (interference from
original conditions) for the following type of asset:
 all piping flange bolting
 all flange bolting of connecting piping to flanged equipment (pressure vessel, heat exchanger,
valve, pipeline and tank)
This document doesn’t cover the following:
 Cast Iron flanges
 Glass-line vessels and piping flanges
 Plastic pipe flanges
 Other non standard flanges
1.3
References
1.
2.
3.
4.
5.
6.
2
API 570, Inspection, Repair, Alteration, and Rerating of In-service Piping Systems
API 510, Pressure Vessel Inspection Code: In-service Inspection, Rating, Repair and Alteration
API 574, Inspection Practices fro Piping System Components
API 572, Inspection of Pressure Vessels
ASME PCC-1 Guidelines for Pressure Boundary Bolted Flange Joint Assembly
COPI document ID-G-BU-00000-00000-01548 In-service Flange Integruty Guideline,
Definition
Hot Bolting – The sequential removal and replacement of individual fasteners on piping flanges with the
system still “live”. Existing fasteners are removed in a predetermined diametrically opposed sequence,
are examined for condition and then either cleaned, lubricated and re-fitted, or replaced by a correctly
specified fastener. Each refurbished or new fastener is then installed and tightened by controlled means
before the next fastener in the sequence is removed.
Preventative Bolting - The practice of checking for looseness and where necessary re-tightening
fasteners in flanged joints on a live (on-line) system. Tightening shall be done by controlled means even if
the bolt is equipped with a load-monitoring device (e.g. Rotabolt).
Tightening - The making tight of a flanged joint by torquing or tensioning the flange bolts.
Procedure/Work Instruction/Job Note:
Flange Management Proceure
ConocoPhillips Indonesia
ID-N-SB-LL0-PRO-ST-00-0001
Page 5 of 32
Torquing - The loading of flange bolts using manual or hydraulic torque equipment
Tensioning- The loading of flange bolts usually using hydraulic equipment.
3
Flange Management Requirement and Procedure
Flange management work flow process is attached in Appendix A. These requirements apply when flange
joints are disturbed for maintenance, repair and/or replacement works.
3.1
Flange Joints Disturbance Procedure
3.1.1
Reference Documentation
Determine the type, size and class of the flange to be bolted. Determine the relevant specification number
of the flange joint. Check the material, coating and size of the stud bolts. Check the type, pressure rating
and size of the gasket. The stud bolts and gasket specifications for the flanged joint must always match
the descriptions in the following documents:

Piping specification: isometric, line index, etc

Pressure vessel specification: data sheet, drawing, MDR, etc.

P&ID (as built drawings)

Heat exchanger specification: data sheet, drawing, MDR, etc.

Tank specification: data sheet, drawing, MDR, etc.

Pipeline specification: data sheet, drawing, MDR, etc.

Valve specification: data sheet, drawing, MDR, etc.
Note: if in doubt contact the COPI Asset Engineering for guidance.
3.1.2
Breaking Flange Joints
1. Before commencing work ensure that the permit to work and risk assessments are valid for the
job in hand, and that the correct protective clothing/equipment is worn. Ensure that all safety
precautions and work permit instruction set out in ID-G-BU-00000-00000-00462 Permit to Work
are in place and are strictly adhered to.
2. Confirm that the line has been isolated, drained/vented or purged as appropriate before
attempting to break a joint. Ensure beyond all doubt that the line or piece of equipment being
worked upon has been correctly isolated and vented to atmospheric pressure and flushed and
purged if appropriate. the isolation requirement set out in ID-G-BU-00000-00000-00404 Lock Out
– Tag Out must be accomplished through an isolation certificate
3. Ensure that the correct tools for the job are available and are used. HSE document# ID-G-BU00000-00000-00391 – Hand Tools shall be complied.
4. The tagging system is used starting from breaking flange joint.
5. When attempting to break a joint, avoid standing directly alongside or underneath the joint.
Always break the bolt that is furthest away from you first, preferably the bottom furthest bolt.
6. Continually check for leakage, seepage or signs of pressure in the line – a hissing sound, a smell
of gas, etc. Use a pair of wedges away from you to determine this.
7. If at any stage there is a sign of pressure in the line, stop work immediately. Re-tighten the joint to
contain the leak, if safe to do so, and then report the situation to the maintenance supervisor or
raise alarm. The line isolation will then have to be checked.
Procedure/Work Instruction/Job Note:
Flange Management Proceure
ConocoPhillips Indonesia
ID-N-SB-LL0-PRO-ST-00-0001
Page 6 of 32
8. Never remove nuts from studs until you have ascertained that the considered pipe/equipment is
depressurized and empty.
9. Before finally parting a joint, always assess the forces on the pipe. Will the joint spring apart? Is
one half of the joint unsupported? Temporary supports or restraints may be required.
3.1.3
Making Joints
All personnel carrying out work on bolted joints should be competent to a level appropriate to the required
technical skills. Similarly, supervisory personnel and assessors should also be competent to ensure they
are aware of the issues involved in achieving a leak free joint. This includes a process to assure third
party vendors and contractors can demonstrate that their personnel are managed using equivalent
competence standards.
1. Before starting, check that the permit to work/risk assessment is valid for the job in hand and that
the correct protective clothing/equipment is worn. Ensure that all safety precautions and work
permit instruction set out in ID-G-BU-00000-00000-00462 Permit to Work are in place and are
strictly adhered to.
2. Check if these are procedure in place for carrying out the intended work – and if so follow the
procedure. This includes using the Flange Disturbance Register and the use of flange
disturbance tags as detailed in section 3.1.4 below.
3. Determine the type, size and class of the flange to be bolted. Determine the referenced
document/specification as described in section 3.1.1 of the concerned joint. Check the material,
coating and size of the stud bolts. Check the type, pressure rating and size of the gasket. The
stud bolts and gasket specifications for the flanged joint must always match the descriptions in
the specification document (as mentioned in section 3.1.1).
4. Only use the correct materials for the job. Never use damaged materials and always uses a new
gasket when making up a joint. It is recommended that nuts/bolts are also renewed, however,
where this is not possible a visual inspection of these parts should be completed prior to
installation.
5. It does not allow to use cut from sheet gasket.
6. Ensure that the correct tools for the job are available and are used. HSE document# ID-G-BU00000-00000-00391 – Hand Tools shall be complied.
7. Ensure the joint faces are clean and properly aligned before inserting the gasket.
8. Visually check the flanges for equal gap. If a larger gap appears on one side of the flange, tighten
the bolt which corresponds with the larger gap first.
9. Ensure the flanges are parallel after tightening.
3.1.4
Tagging Procedure
Each disturbed flange shall be ’tagged’ prior to assembly, only one flange tag per flange/joint will
be fitted. The tags are double-sided and comprise four distinct sections, the outer three sections
being perforated to allow tear off (all four sections of the tag are pre-printed with a unique
number). Tag should be made from water proof material e.g. plastic.
Flange disturbance tagging is given in Appendix B.
Procedure/Work Instruction/Job Note:
Flange Management Proceure
ConocoPhillips Indonesia
Section 4




ID-N-SB-LL0-PRO-ST-00-0001
Page 7 of 32
Section 3
Section 2
Section 1
Section 1 (Flange Not Disturbed)
Section 2 (Flange Not Tightened)
Section 3 (Flange Not Tested)
Section 4 (Main body of tag which will initially remain on the flange)
When Section 4 has been completed (on both sides), the tag indicates that the flange has been
assembled and tightened competently.
The tag should be fitted using a suitable tie and, in a position, adjacent to or on the joint.
Section 1 is removed and returned to the Maintenance Supervisor/Work leader to indicate that
flange has been disturbed. Person who disturbs the flange shall fill date and his/her name
complete with Permit work Number.
Section 2 is removed and returned to the Maintenance Supervisor/Work Leader to provide a
visual indication that the flange has been tightened and ready to be leak tested. The Work Lead
responsible for the tightening operation shall advise the Maintenance Supervisor/Work Leader of
the name of the technician tightening each flange and be responsible for the return of Section 2 to
the Construction/Maintenance Supervisor.
Section 3 is removed and returned to the Maintenance Supervisor/Work Leader to provide a
visual indication that the flange has been leak tested. The supervisor responsible for the leak test
operation shall advise the Maintenance Supervisor/Work Leader of the name of the technician
performing the test and be responsible for the return of Section 3 to the
Construction/Maintenance Supervisor. If the result of the leak test is failure due to a leaking
flange, a new tag should be assigned to the joint prior to rework.
Section 4 of the tag will remain on the flange until such time that further maintenance is carried
out, only then will the existing tag be removed and replaced with a new tag. This shows visually
that both operations have been completed upon that flange.
PSSR shall be performed before joints back to online and operation should perform site
verification to check tagging system.
Procedure/Work Instruction/Job Note:
Flange Management Proceure
ConocoPhillips Indonesia
ID-N-SB-LL0-PRO-ST-00-0001
Page 8 of 32
Side A: This side of tag is completed by the Worker/Technician assembling the flange. The
worker/technician shall print his name and confirm the acceptable condition of the;
a) Flange face cleanliness
b) Flange alignment - Acceptance criteria given in relevant specification.
c) Material and length of the bolts - Acceptance criteria given in relevant document described in
section 3.1.1.
d) Size and material of the gasket.- Acceptance criteria given in document relevant document
described in section 3.1.1.
e) Correctly Lubricated. – See section 3.2.2
Side B: When the flange is ready for bolt tensioning/torquing, the Worker/Technician shall check
Side A of the tag to confirm the flange had been assembled correctly. The Worker/Technician can
then proceed to tighten the flange.
When bolt tightening is completed, the Worker/Technician shall print his name and confirm;
a) System Number
b) Line Number
c) The torque or tension applied. – Measured using hydraulic pressure gauges mounted on the
torque/tensioning machinery or set point on manual torque wrenches.
On completion of the above, Section 2 of the tag is removed and returned to the
Operation/Maintenance Supervisor/Work Leader who will retain it in the work pack for close out
audit.
A similar process is utilized after the flange has been leak tested (for information on leak testing
refers to Pressure and Leak Testing Guidelines.
The leak tests (service tests) are carried out with the pressure system in service, normally during
start-up. The test is normally carried out (but not necessarily always) at maximum normal
operating pressure using the process fluid as the test medium, supplemented by water or inert
gas from an external source if necessary.
When the flange has successfully passed a test, the Leak Test Technician shall confirm and write
on Side B Pressure and date of test then remove Section 2 of the tag and return it to the
Maintenance Supervisor/Work Leader who will insert the perforated ticket in the work pack for
close out audit.
On completion of testing the permit to work should be signed off as complete before handover
back to the operations department.
When all flanges have been tightened and tested the remaining portion of the tag should be kept
at disturbed flanges for at least 3 months after the start-up is complete. After that it is at the
discretion of the Facility Management as to how long the tags are kept.
3.2
Flange General Requirements
3.2.1
Bolting
To ensure consistent performance, it is essential that nuts and bolts are supplied with the precise
specification for tolerance and fit. Studs/Nuts shall be the correct material and size/length for the
application and free of corrosion, damage, dirt and grit.
Confirmation of the above is required to complete Section 4 of Side A of the flange tag.
Bolt Length – Bolts should extend completely through their nuts.
Re-use of Bolts/Studs
Studs and or nuts can only be reused, subject to the following conditions:
 There is no noticeable degradation.
Procedure/Work Instruction/Job Note:
Flange Management Proceure
ConocoPhillips Indonesia
ID-N-SB-LL0-PRO-ST-00-0001
Page 9 of 32
 They are free from obvious defects (corrosion, cracks, etc.).
 There is no sign of yielding (i.e. deformed threads, stud shaft, etc).
 Nuts must run freely by hand on the bolt.
If a stud or nut is found to be unsuitable for re-use, it shall be scrapped
immediately.
For joint assemblies on the critical path of a maintenance or shutdown program (or where tight
time schedules are to be adhered to), it is recommended that replacement bolting be made
available in case the existing bolting is found to be unfit to return to service.
It is essential that when choosing fasteners for a flanged joint the grade of stud and nut used are
compatible and compliant with the piping specification. Matching stud and nut grades are given in
Table below:
Table-3 Stud and Nut Compatible
Stud
3.2.2
Compatible Nut
ASTM Material
Marking
ASTM Material
Marking
A193 Grade B7
B7
A194 Grade 2H
2H
A193 Grade B7M
B7M
A194 Grade 2HM
2HM
A193/A320 Grade B8 Class 2
B8
A194 Grade 8
8
A193/A320 Grade B8M Class 2
B8M
A194 Grade 8M
8M
A193 Grade B16
B16
A194 Grade 4
4
A320 Grade L7
L7
A194 Grade 4 or 7
4 or 7
Thread Lubricants and Preservatives
1. The torque/tensioning values given in Appendices F as a general guidance. If required the
calculation should be made by using ASME PCC-1 for a specific flange
2. The use of lubricants with a lower coefficient of friction can lead to excessive bolt stress being
applied and failure of flanges or bolts may result.
3. Friction coefficient (COF) of some preservative lubricant can be referred at Appendix D.
4. When bolt tensioning is complete, to prevent corrosion a liberal coating of lubricant should be
applied to the nuts up to the back of the flange, and to the stud ends protruding from the nuts.
Copperslip, Densotape or nut/thread protectors are considered to be suitable for this purpose.
5. The above information is required to complete Section 4 of Side B of the flange tag.
Note: this is particularly important where low alloy bolts are used on unpainted stainless steel
flanges. Marinel material bolting should not be lubricated.
3.2.3
Flange Faces
Prior to assembly the flanges should be inspected to ensure the faces are in good condition
(particularly with respect to radial scoring), clean, parallel and axially aligned.
Pipe flange alignment tolerances shall comply with the relevant pipe fabrication/erection
specification.
Any deviation of tolerances shall be put in IAAN process.
Procedure/Work Instruction/Job Note:
Flange Management Proceure
ConocoPhillips Indonesia
ID-N-SB-LL0-PRO-ST-00-0001
Page 10 of 32
Flange alignment is critical to the performance of the bolted joint. No excess pressure should be
exerted to align the bolt holes for the insertions of bolts without engineering approval. Excess
pressure used to assist with the insertion of bolts on flanges on rotating equipment could have
damaging effects on seals, shafts and bearings. For specific information on pipe alignment on
rotating equipment see API 686. General piping alignment specifications can be found in ASMEPCC-1.
Every effort shall be made to align the joint. Applying large forces, through mechanical devices or
bolting, to align flange joint is bad practice and not permitted. Joints found in this condition should
be reported and seek consultation with COPI Asset Engineering prior to re-commissioning.
The above information is required to complete Section 4 of Side A of the flange tag.
If in doubt contact the COPI Asset Engineering for guidance.
3.2.4
Gaskets
A new gasket/RTJ/Seal Ring shall be used whenever joints are made or remade.
Gaskets shall be suitable for the operating conditions and remain flexible under a varying load
due to fluctuations in pressure and temperature. The type of gasket used shall comply with the
Pipe Specification. Where spiral wound gaskets are utilized, extra care shall be taken to protect
the face of the gasket.
When installing the gaskets, ensure the flange and gasket faces are clean and dry. Gaskets
should be of the correct type and correctly positioned. Note that it is not possible to mix and
match gaskets between proprietary clamped connectors (e.g. Graylok/Techloc & Galperti).
3.2.5
Insulation Gasket Sets and Specialty Gasket
Where identified, it is imperative that insulation kits are fitted correctly. The purpose of the
insulation kit is to prevent undesired conductivity between dissimilar materials and corrosion
issues occurring. Insulation kits generally require a lesser bolt load to create an effective seal as
a result of the specially designed gasket, with spacers and washers playing an integral role. It is
essential that all components of the insulation kit are fitted to ensure the integrity of the joint and
that the manufacturer’s recommendations are followed when tightening the joint.
Note: A lower torque must be used for insulation kits to avoid cracking. If cracks or
damage occur whilst tightening the insulation kits must be replaced as they are no longer
usable.
3.3
Tightening
3.3.1
Tightening Methods
The following table is general rule for selection of tightening method:
Table-4 Torque/Tension Guidance based on bolt size and flange class
Bolt Size
Flange Class
Tension
1 ½ and larger
900# and above
Yes
1 ½ and larger
Below 900#
Yes
Below 1 ½
900# and above
Yes
Torque
Comments
Tension whenever possible,
torquing may be utilized only if
tensioning is not possible
Yes
Tension whenever possible,
torquing may be utilized only if
tensioning is not possible
Tension whenever possible,
torquing may be utilized only if
Procedure/Work Instruction/Job Note:
Flange Management Proceure
ConocoPhillips Indonesia
Bolt Size
Flange Class
ID-N-SB-LL0-PRO-ST-00-0001
Page 11 of 32
Tension
Torque
Comments
tensioning is not possible
Below 1 ½
Below 900#
Not
Required
Yes
The equipment must have a valid calibration certificate.
3.3.1.1
Conventional Spanners/Wrenches
Flange bolts may be tightened by hand torque wrenches Conventional spanners/wrenches may
be used on Class 150 Non-Severe System piping systems only.
Note: the flogging of bolts in hydrocarbon systems is not permitted.
3.3.1.2
Torque Wrenches
Flange bolts shall be tightened by torque wrenches on all hydrocarbon systems (all pressure
ratings), and utility systems rated at Class 300 and above.
Controlled torque wrenching shall be carried out using either manual or hydraulic torque
wrenches that are calibrated and “in certification”. The method chosen is dependent upon bolt
loading, access, clearance and tooling availability, which will be determined by the site personnel.
When the bolt loading requires a torque figure greater than 500 lbf.ft (678 Nm) to be applied, the
use of a hydraulic torque wrenches is recommended.
Note: if torque equipment cannot be applied due to access restrictions, then the
Operation/Maintenance Supervisor/Lead shall be advised and a Risk Assessment
completed detailing the additional controls required to ensure joint integrity, this may
include using conventional spanners and joint make up verification by a second
Worker/Technician.
3.3.1.3
Torquing Procedure
Figure 1 Tightening Sequence
Procedure/Work Instruction/Job Note:
Flange Management Proceure
ConocoPhillips Indonesia
ID-N-SB-LL0-PRO-ST-00-0001
Page 12 of 32
To achieve joint tightness, it is important that the following procedure is adhered to:
(1) Check and ensure that the general requirements of Section 3.2 have been satisfied.
(2) To achieve uniform joint load/stress distribution the bolts shall be tightened in three stages,
representing 30%, 60% and 100% of the torque values stated in Appendices F. At each
stage of tightening, bolts shall be tightened in a controlled sequence as follows:
(3) Finally, the bolts shall be chased round using the 100% torque value stated in Appendices F,
until uniform tightening has been achieved. Note: If tightening an RTJ, a second 100% chase
round shall be completed.
3.3.1.4
Hydraulic Jack Bolt Tensioning Equipment
Where more stringent control of joint stresses is required, flange bolting should, whenever
practical, be tightened using hydraulic jack tensioning equipment. This technique is strongly
recommended for the following services and pressure ratings, (also see Appendices H)
(1) Bolt diameters of 2 inches and above in all services with pressure ratings up to and including
Class 900.
(2) Bolt diameters of 1½ inches and above in all services with pressure ratings Class 1500 and
above.
(3) Bolt diameters of 1 inch and above in critical applications. Critical applications are
considered to be joints exposed to cyclic stress i.e. frequent changes of pressure and/or
temperature.
The bolt tensioning operation must be carried out
manufacturer’s specified procedure and the load
tensioning should be applied simultaneously to all
possible, tensioning should be applied in phases
guidelines.
in accordance with the tension equipment
loss factors should be recorded. Ideally
studs in one operation. Where this is not
using differing pressures as per suppliers
Note: if tensioning equipment cannot be applied due to access restrictions then the
Operation/Maintenance Supervisor/Lead shall be advised and a Risk Assessment
completed detailing the additional controls required to ensure joint integrity, this may
include using conventional spanners and joint make up verification by a second
Worker/Technician.
Procedure/Work Instruction/Job Note:
Flange Management Proceure
ConocoPhillips Indonesia
3.4
3.4.1
ID-N-SB-LL0-PRO-ST-00-0001
Page 13 of 32
Hot Bolting and Preventative Bolting
Hot Bolting Requirement
The practice of hot bolting (see definitions) is a potentially hazardous operation and must not be
undertaken unless all other options have been considered and there remains an outstanding, and
fully justified, operational reason to carry out hot bolting in a safe manner. A risk assessment shall
be carried out, and a plan developed to achieve isolation of the joint in the event of a problem
during the hot bolting operation. Changing bolts by hot bolting simply to save time during a
forthcoming shutdown is not an adequate reason for hot bolting. However, partially backing off
and re-tightening one nut at a time is permitted to identify bolts that may be difficult to remove in a
later shutdown, but shall be subject to the same safety review, and risk assessment and controls
as for hot bolting.
Holt bolting work should be approved by site manager and site specific procedure should be
developed.
Hot bolting may only be considered on systems in the following duties:
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
Seawater and Service water
Fire water ring mains
Cooling medium
Crude Oil systems provided the system pressure does not exceed 5.0 barg.
Diesel fuel
Drains systems
Low-pressure mud conveying systems associated with drilling.
The operating pressure must be less than 75% of the MAWP (Maximum
Allowance with Pressure) of the piping or process system to be hot
bolted).
Hot Bolting is NOT permitted on the following systems:
(1)
(2)
(3)
(4)
(5)
(6)
3.4.2
Hydrocarbon gas
High pressure Water Injection >25 barg
Toxic fluids
Fluid temperature > 90 degrees C
Intermittent flow or surging flow
Flange with bolt less than eight (8).
Hot bolting procedure
Before any work commences ensure that hot bolting has been fully justified; that a risk
assessment has been performed and approved; that a permit to work states that hot bolting on
the joint is permitted; and that a contingency plan exists to isolate the joint in the event of a
problem during the hot bolting operation.
The hot bolting procedure given below shall be followed:
(1) Latest past history records of the joints in question shall be consulted to identify any
anomalies or previous problems with the joint.
(2) To anticipate any fastener or flange or gasket relaxation an attempt shall first be made to
evenly re-tension each fastener before attempting to loosen any single fastener. Both the
tightening and slackening activities shall be carried out by controlled means (if extra length
studs have been fitted, bolt tensioning is strongly recommended over torquing during hot
bolting as it maintains a more accurate gasket seating stress, and is less likely to result in an
overloaded bolt). Bolt tension and bolt torques shall be in accordance with Appendix F.
(3) The break out torque shall be recorded for every fastener. If the break out torque is
significantly less than the torque specified in Appendix F it may indicate a loose or
overstressed joint. In such cases the system shall be isolated, depressurized, purged and
Procedure/Work Instruction/Job Note:
Flange Management Proceure
ConocoPhillips Indonesia
ID-N-SB-LL0-PRO-ST-00-0001
Page 14 of 32
vented prior to any further fastener being removed. In this instance please notify the COP
onshore maintenance responsible engineer.
(4) Proceed to slacken the first fastener (on the side furthest away from personnel), monitoring
for leakage continuously. Under no circumstances shall two bolts be slackened
simultaneously. In the event of the gasket leaking the joint shall be immediately re-tightened.
(5) The removed stud and nut should be cleaned, examined for damage or strain, lubricated with
Copperslip only, reinstalled and re-tightened. If in doubt the stud and nut should be replaced.
(6) Only one fastener shall be removed and replaced at a time working in the diametrically
opposite sequence as shown in Table 1 of this procedure. Each fastener shall be replaced
immediately and shall be tightened to the torque or tension as specified in Appendix F.
(7) Continue with this procedure (6) until all the fasteners have been changed out.
(8) When all fasteners have been replaced their exposed nuts and threads shall be given a
liberal coating of grease in order to prevent corrosion.
(9) Any jacking bolts that have been removed to improve access should be greased and refitted.
(10) Verify that the joint is totally leak-free.
3.4.3
Preventative Maintenance Bolting
The practice of checking for looseness and where necessary re-tightening fasteners in flanged
joints on a live (on-line) system is a potentially hazardous operation. It must not be undertaken on
a joint in a hydrocarbon, hazardous or toxic fluid system, unless all other options have been
considered and there remains an outstanding, and fully justified, operational reason to perform
preventative maintenance bolting in a safe manner. A risk assessment shall be carried out, and a
plan developed to achieve isolation of the joint in the event of a problem during the operation. The
joint must have a minimum of 8 bolts. This preventive works shall get approval from site
management representative.
3.4.4
Preventative Maintenance Bolting Procedure
(1) Bolt tightening shall be carefully performed by controlled means. Bolt tensioning shall be
used if possible (if extra length studs have been fitted), otherwise bolt torquing shall be used.
Controlled tightening shall be used even if the bolt is equipped with a load-monitoring device
(e.g. Rotabolt).
(2) Re-tensioning and re-torquing of the flange bolting shall be performed in accordance with
Appendix F, and bolt torquing shall be in the bolt sequence shown in Table 1 of this
procedure. It should be noted that although the thread lubricant may have dried out which will
increase friction losses, the bolt torque applied must not exceed the values stated in
Appendix F.
(3) Monitor the joint during the operation for leakage, and at the end of the work verifies that the
joint is totally leak-free.
4
Flange System Records
The certainty of a successful joint being made up increases if data is controlled and historical data exists
on the activities carried out in the past. Recording traceable data encourages best practice at the time of
the activity, and will provide useful planning data for the next time the joint is disturbed.
Procedure/Work Instruction/Job Note:
Flange Management Proceure
ConocoPhillips Indonesia
ID-N-SB-LL0-PRO-ST-00-0001
Page 15 of 32
Learning from incident is important. A gathering relevant data, which should be collected by everyone
involved in flanged joints and periodically reviewed to establish trends, performance and improvement.
This can be achieved if records and data are kept as part of a management control process.
It is recommended that as a minimum keeps records for all joints those on other services which have a
history of leakage, or potential to leak, and that this is kept with any relevant procedures for monitoring
specific joint. To minimize the possibility of the problem resurfacing, methods for countering the leak
should be included within the individual joint records.
Any changes from original specification should be maintained through MOC process.
Maintenance/Operation
Supervisor/Lead
Offshore Installation
Manager
Asset Integrity/Pipeline
Engineer
1
Perform Visual Inspection
I
I
I
C
R
A
2
Perform Fugitive Emission
I
I
I
C
R
A
3
Perform Snoop Leak Detector
R
C
A
I
I
Specialist Flange Vendor
Work/Technician Leader
IN-SERVICE ROUTINE INSPECTION
RACI
R
A
C
I
Responsible
Accountable
Consult
Inform
Activity
Asset Integrity/Pipeline
Engineer
InspectorsAsset Integrity
Asset Integrity Mgr.
No
Responsible
Accountable
Consult
Inform
Asset Engineering Team
R
A
C
I
Field Manager
RACI
Offshore Installation
Manager/ Operation Spt./
Maintenance Spt./ Pipeline
Superintendent
FLANGE MANAGEMENT
REQUIREMENT & PROCEDURE
Operation Supervisor/Lead
Maintenance
Supervisor/Lead
No
Asset Integrity Mgr.
Mechanical Lead /
Technician
InspectorsAsset Integrity
Responsibilities
Worker / Technician
5
R
A
C
C
I
C
R
A
C
I
I
I
C
R
A
I
I
C
C
C
A
I
I
I
C
C
A
I
I
I
Activity
1
Overall accountability for compliance with this
guideline
2
Site Accountability for compliance with this
procedure
3
Determine Flanges to be disturbed during each task
4
Completion of Side A of Flange disturbance Tag
R
R
5
Confirm Method of tightening to be used
R
R
C
Procedure/Work Instruction/Job Note:
Flange Management Proceure
ConocoPhillips Indonesia
ID-N-SB-LL0-PRO-ST-00-0001
Work/Technician Leader
Operation Supervisor/Lead
Maintenance
Supervisor/Lead
Offshore Installation
Manager/ Operation Spt./
Maintenance Spt./ Pipeline
Superintendent
Asset Engineering Team
Asset Integrity/Pipeline
Engineer
InspectorsAsset Integrity
Torque/Tension to correct Value
R
R
C
C
A
I
I
I
7
Complete disturbed flange tightening report
R
R
C
C
A
I
I
I
8
Complete Side B of flange disturbance Tag
R
R
C
C
A
I
I
I
9
Leak Test As Required
R
R
C
C
A
I
I
I
10
Close out entry within flange management database
and complete flange disturbance register
R
R
C
C
A
I
I
I
11
Close Work Order within SAP
C
C
C
R
A
12
Original of P&ID’s/Isometric, Flange Tag, and
controlled tightening reports to be kept.
C
C
C
R
A
RACI
R
A
C
I
Responsible
Accountable
Consult
Inform
I
I
I
I
I
Asset Integrity Mgr.
Specialist Flange Vendor
6
FLANGE MANAGEMENT
REQUIREMENT & PROCEDURE
Field Manager
Worker / Technician
Page 16 of 32
Procedure/Work Instruction/Job Note
In- Service Flange Integrity Guideline
ConocoPhillips Indonesia
ID-G-BU-00000-00000-01548 Rev. 2
Page 17 of 32
APPENDIX A
FLANGE MANAGEMENT PROCEDURE FLOWCHART
L:\2.0 Project\16
Material & Corrosion\
Procedure/Work Instruction/Job Note
In- Service Flange Integrity Guideline
ConocoPhillips Indonesia
ID-G-BU-00000-00000-01548 Rev. 2
Page 18 of 32
APPENDIX-B
FLANGE DISTURBACE TAG
L:\2.0 Project\16
Material & Corrosion\
Procedure/Work Instruction/Job Note
In- Service Flange Integrity Guideline
ConocoPhillips Indonesia
ID-G-BU-00000-00000-01548 Rev. 2
Page 19 of 32
APPENDIX-C
CONTROLLED TIGHTENING REPORT
L:\2.0 Project\16
Material & Corrosion\
Procedure/Work Instruction/Job Note:
In- Service Flange Integrity Guideline
ConocoPhillips Indonesia
ID-G-BU-00000-00000-01548 Rev. 2
Page 20 of 32
APPENDIX-D
LUBRICANT
Procedure/Work Instruction/Job Note:
In- Service Flange Integrity Guideline
ConocoPhillips Indonesia
ID-G-BU-00000-00000-01548 Rev. 2
Page 21 of 32
No.
Lubricant's Product
Producer
Coefficient Of Friction
1
API Bull 5A2
-
0.13
2
Anti Seize
Acheson Colloids
0.09
3
Anti Seize (paste)
Chesteron
International
0.14
4
Beldamite ASC
Beldonite
0.13
5
Berutex FH-34
R.S. Clare
0.16
6
Berutex FH-35
R.S. Clare
0.16
7
Biral BASC
Sieben Technical
0.11
8
Castrol Nucleol S202
Castrol
0.08
9
Copaslip
National Chemical Co
0.12
10
Coppercrest
Illex Lubricant
0.14
11
Copper Ease
Comma Oil &
Chemical
0.14
12
Coppergrease
Chemodex
0.15
13
**Coppergrease
Chemofina
0.11
14
Copperslip
Belzona Molecular Ltd
0.09
15
**DAG156
Acheson Colloids
0.15
16
DAG580 (Dry Lubricant)
Acheson Colloids
0.16
17
Easyrun100
K.S Paul
0.08
18
Fel-ProC-102
Fel-Pro Inc
0.16
19
Fordec Copper Anti Seize
Fordec
0.15
20
Gleitmo165
Gleitmo
0.1
21
HP anti seize
Belzona Molecular Ltd
0.15
22
LFCP 5006
Maxol (Irish)
0.2
23
Molykote Cu-7439
Dow Corning
0.15
24
Molykote1000
Dow Corning
0.11
25
Molykote Q5-7405
Dow Corning
0.04
26
Molykote G-Rapid
Dow Corning
0.08
27
Molykote G-Rapid Plus
Dow Corning
0.09
28
Molykote HSC
Dow Corning
0.11
29
Molykote Ti 1200
Dow Corning
0.12
30
Molykote 7443
Dow Corning
0.13
31
Molykote P37 paste
Dow Corning
0.12
32
Molyslip AS60
Molyslip
0.07
33
Never seez Std grade
(NS160)
Bostik Ltd
0.18
34
Never seez Spl grade
(NS165)
Bostik Ltd
0.18
35
Nickel-Eez
Swan Chemical
0.12
Procedure/Work Instruction/Job Note:
In- Service Flange Integrity Guideline
ConocoPhillips Indonesia
ID-G-BU-00000-00000-01548 Rev. 2
Page 22 of 32
No.
Lubricant's Product
Producer
Coefficient Of Friction
36
OKS 235
OKS
0.11
37
OKS 240
OKS
0.12
38
OKS 250
OKS
0.08
39
OKS 503
OKS
0.06
40
OKS 504
OKS
0.09
41
OKS 505
OKS
0.1
42
OKS 506
OKS
0.11
43
OKS 507
OKS
0.1
44
Omega 99
Sovereign Lubricants
0.13
45
Omega 99N
Sovereign Lubricants
0.09
46
Omega 95
Sovereign Lubricants
0.12
Procedure/Work Instruction/Job Note:
In- Service Flange Integrity Guideline
ConocoPhillips Indonesia
ID-G-BU-00000-00000-01548 Rev. 2
Page 23 of 32
APPENDIX-E
FLANGE BOLTING CHARTS
Procedure/Work Instruction/Job Note:
In- Service Flange Integrity Guideline
ConocoPhillips Indonesia
ID-G-BU-00000-00000-01548 Rev. 2
Page 24 of 32
Series 150 Flange *For standard flanges only, Add
length when washers or Double Nuts are used
Pipe
Size
Wrench
Size
Flange Bolts
Number
Diameter
Raised Face
Ring Joint
Length
Length
Ring#
1
⅞
4
½
2½
3
R15
1½
⅞
4
½
2¾
3¼
R19
2
1 1/16
4
⅝
3¼
3¾
R22
3
1 1/16
4
⅝
3½
4¼
R29
4
1 1/16
8
⅝
3½
4¼
R36
6
1¼
8
¾
4
4½
R43
8
1¼
8
¾
4¼
4¾
R46
12
1 7/16
12
⅞
4¾
5½
R56
14
1⅝
12
1
5¼
6
R59
16
1⅝
16
1
5¼
6
R64
18
1 13/16
16
1⅛
6
6½
R68
20
1 13/16
20
1⅛
6¼
7
R72
24
2
20
1¼
7
7¾
R76
Series 300 Flange *For standard flanges only, Add
length when washers or Double Nuts are used
Pipe
Size
Wrench
Size
Flange Bolts
Number
Diameter
Raised Face
Ring Joint
Length
Length
Ring#
1
1 1/16
4
⅝
3
3¼
R16
1½
1¼
4
¾
3½
4
R20
2
1 1/16
8
⅝
3½
4¼
R23
3
1¼
8
¾
4¼
5
R31
4
1¼
8
¾
4½
5¼
R37
6
1¼
12
¾
4¾
5¾
R45
8
1 7/16
12
⅞
5½
6¼
R49
10
1⅝
16
1
6¼
7¼
R53
12
1 13/16
16
1⅛
6¾
7½
R57
14
1 13/16
20
1⅛
7
7¾
R61
16
2
20
1¼
7½
8¼
R65
18
2
24
1¼
7¾
8½
R69
20
2
24
1¼
8
9¼
R73
Procedure/Work Instruction/Job Note:
In- Service Flange Integrity Guideline
ConocoPhillips Indonesia
ID-G-BU-00000-00000-01548 Rev. 2
Page 25 of 32
Series 600 Flange *For standard flanges only, Add
length when washers or Double Nuts are used
Pipe
Size
Wrench
Size
Flange Bolts
Number
Diameter
Raised Face
Ring Joint
Length
Length
Ring#
1
1 1/16
4
⅝
3½
3½
R16
1½
1 ¼
4
¾
4¼
4¼
R20
2
1 1/16
8
⅝
4¼
4½
R23
3
1 ¼
8
¾
5
5¼
R31
4
1 7/16
8
⅞
5¾
6
R37
6
1⅝
12
1
6¾
7
R45
8
1 13/16
12
1⅛
7¾
8
R49
10
2
16
1¼
8½
8¾
R53
12
2
20
1¼
8¾
9
R57
14
2 3/16
20
1⅜
9¼
9½
R61
16
2⅜
20
1½
10
10 ¼
R65
18
2 7/16
20
1⅝
10 ¾
11
R69
20
2 7/16
24
1⅝
11 ½
11 ¾
R73
Series 900 Flange *For standard flanges only, Add
length when washers or Double Nuts are used
Pipe
Size
Wrench
Size
Flange Bolts
Number
Diameter
Raised Face
Ring Joint
Length
Length
Ring#
1
1 7/16
4
⅞
5
5
R16
1 ½
1⅝
4
1
5½
5½
R20
2
1 7/16
8
⅞
5¾
6
R24
3
1 7/16
8
⅞
5¾
6
R31
4
1 13/16
8
1⅛
6¾
7
R37
6
1 13/16
12
1⅛
7¾
8
R45
8
2 3/16
12
1⅜
7¾
9
R49
10
2 3/16
16
1⅜
9¼
9½
R53
12
2 3/16
20
1⅜
10
10 ¼
R57
14
2⅜
20
1½
10 ¾
11 ¼
R62
16
2 9/16
20
1⅝
11 ¼
11 ¾
R66
18
2 15/16
20
1⅞
13
13 ½
R70
20
3⅛
20
2
13 ¾
14 ½
R74
Procedure/Work Instruction/Job Note:
In- Service Flange Integrity Guideline
ConocoPhillips Indonesia
ID-G-BU-00000-00000-01548 Rev. 2
Page 26 of 32
Series 1500 Flange *For standard flanges only, Add
length when washers or Double Nuts are used
Pipe
Size
Wrench
Size
Flange Bolts
Number
Diameter
Raised Face
Ring Joint
Length
Length
Ring#
1
1 7/16
4
⅞
4¾
4¾
R16
1 ½
1⅝
4
1
5¼
5¼
R20
2
1 7/16
8
⅞
5½
5¾
R24
3
1 13/16
8
1⅛
6¾
7
R35
4
2
8
1¼
7½
7¾
R39
6
2 3/16
12
1⅜
10
10 ¼
R46
8
2 9/16
12
1⅝
11 ¼
11 ¾
R50
10
2 15/16
12
1⅞
13 ¼
13 ½
R54
12
3⅛
16
2
14 ¾
15 ¼
R58
14
3½
16
2¼
16
16 ¾
R63
16
3⅞
16
2½
17 ½
18 ½
R67
18
4¼
16
2¾
18 ¼
20 ¼
R71
20
4⅝
16
3
21
22 ¼
R75
Series 2500 Flange *For standard flanges only, Add
length when washers or Double Nuts are used
Pipe
Size
Wrench
Size
Flange Bolts
Number
Diameter Raised Face
Ring Joint
Length
Length
Ring#
1
1 7/16
4
⅞
5¾
5¾
R18
1 ½
1 13/16
4
1⅛
7
7¼
R23
2
1⅝
8
1
7¼
7½
R26
3
2
8
1¼
9
9¼
R32
4
2⅜
8
1½
10 ¼
10 ¾
R38
6
3⅛
8
2
13 ¾
14 ½
R47
8
3⅛
12
2
15 ¼
16
R51
10
3⅞
12
2½
19 ½
20 ½
R55
12
4¼
16
2¾
21 ½
22 ½
R60
Procedure/Work Instruction/Job Note:
In- Service Flange Integrity Guideline
ConocoPhillips Indonesia
ID-G-BU-00000-00000-01548 Rev. 2
Page 27 of 32
‘
APPENDIX-F
BOLT TORQUE/TENSIONING VALUES
Procedure/Work Instruction/Job Note:
In- Service Flange Integrity Guideline
ConocoPhillips Indonesia
ID-G-BU-00000-00000-01548 Rev. 2
Page 28 of 32
The following table covers the Torquing / Tensioning Details for the following Bolting Materials:
Carbon Steel, Duplex Stainless Steel, Super Austenitic Stainless Steel, B7 & Equivalent (Bolt Stress is
approx 310 Mpa (45000 psi)) using a Coefficient of Friction (COF) 0.10
Stud Bolt Details
Bolt Size
Thread
¼
UNC
5/16
Required Bolt
Tension (lbf)
Required Torque
Recommended Tool
Details
Ft.lbs
N.m
1672
6
8
Manual Wrench
UNC
2700
12
16
Manual Wrench
⅜
UNC
3952
20
27
Manual Wrench
7/16
UNC
5406
31
41
Manual Wrench
½
UNC
7157
46
62
Manual Wrench
9/16
UNC
9135
64
87
Manual Wrench
⅝
UNC
11322
90
120
Manual Wrench
¾
UNC
16584
150
205
Hydraulic Wrench
⅞
UNC
22778
240
325
Hydraulic Wrench
1
UNC
27681
330
450
Hydraulic Wrench
1⅛
UN8
36537
480
650
Hydraulic Wrench
1¼
UN8
45529
660
890
Hydraulic Wrench
1⅜
UN8
56110
880
1200
Hydraulic Tensioner
1½
UN8
67796
1150
1550
Hydraulic Tensioner
1⅝
UN8
81307
1500
2000
Consult
1¾
UN8
94480
1850
2500
Consult
1⅞
UN8
109478
2300
3100
Hydraulic Tensioner
2
UN8
125581
2700
3700
Hydraulic Tensioner
2¼
UN8
161101
4000
5400
Hydraulic Tensioner
2½
UN8
201038
5400
7300
Hydraulic Tensioner
2¾
UN8
245394
7200
9800
Hydraulic Tensioner
3
UN8
294167
9400
12700
Hydraulic Tensioner
3¼
UN8
347358
12000
16200
Hydraulic Tensioner
3½
UN8
404967
15000
20200
Consult
3¾
UN8
466994
18400
25000
Hydraulic Tensioner
4
UN8
533439
22400
30300
Consult
Procedure/Work Instruction/Job Note:
In- Service Flange Integrity Guideline
ConocoPhillips Indonesia
ID-G-BU-00000-00000-01548 Rev. 2
Page 29 of 32
B8M Class 2 (Bolt Stress is approximately 65% of yield load) using a Coefficient of Friction (COF) 0.10
Stud Bolt Details
Bolt Size
Thread
¼
UNC
5/16
Required Bolt
Tension (lbf)
Required Torque
Recommended Tool
Details
Ft.lbs
N.m
2295
8
11
Manual Wrench
UNC
3705
16
21
Manual Wrench
⅜
UNC
5423
27
37
Manual Wrench
7/16
UNC
7418
42
56
Manual Wrench
½
UNC
9821
62
85
Manual Wrench
9/16
UNC
12535
87
118
Manual Wrench
⅝
UNC
15537
120
165
Manual Wrench
¾
UNC
22756
210
280
Hydraulic Wrench
⅞
UNC
26321
275
375
Hydraulic Wrench
1
UNC
31987
380
520
Hydraulic Tensioner
1⅛
UN8
34304
450
610
Hydraulic Tensioner
1¼
UN8
42747
620
830
Hydraulic Tensioner
1⅜
UN8
40524
640
860
Hydraulic Tensioner
1½
UN8
48963
830
1120
Hydraulic Tensioner
B8M Class 2 Yield Strength:
ASTM Material - Size
Yield Strength
(psi)
65% Yield Strength
(psi)
ASTM A193 – B8M Class 2 – For ¾” and under
95000
61750
ASTM A193 – B8M Class 2 – For ¾” to 1”
80000
52000
ASTM A193 – B8M Class 2 – For 1” and to 1 ¼”
65000
42250
ASTM A193 – B8M Class 2 – For 1 ¼” to 1 ½ “
50000
32500
Procedure/Work Instruction/Job Note:
In-Service Flange Integrity Guideline
ConocoPhillips Indonesia
ID-G-BU-00000-00000-01548 Rev. 2
Page 30 of 32
APPENDIX-G
GUIDELINE FOR EVALUATING FAILURE IN FLANGED JOINTS
Procedure/Work Instruction/Job Note:
In-Service Flange Integrity Guideline
ConocoPhillips Indonesia
ID-G-BU-00000-00000-01548 Rev. 2
Page 31 of 32
GUIDELINE FOR EVALUATING FAILURE IN FLANGED JOINTS
Failure Mode
Cause
Corrective Actions
FLANGE
Flange surface scarred

Installation error in the
tools used to insert or remove
the gasket

Damaged flange was not
inspected during make up

Flanged bowed


Over torque
Flange pressure rating is
too low for service conditions

Flange material is not
adequate for service conditions

Flange rotation



Over torque
Flange pressure rating is
too low for service condition
Renew sealing surface
Revise assembly
procedure
Revise assembly
procedure

New Flange
GASKET
Gasket crush all around


Over torque
Gasket is too soft: low
modulus of elasticity

Gasket is too thick

Install a proper new
gasket
Gasket crush on one end
only



Excessive pipe moments
Pipe misalignment
Incorrect bolt up
procedure


Additional passes
In tightened correctly
refer to Asset Integrity
Engineer
Gasket crush on outer edge



Flange rotation
Over torque
Gasket is too hard: high
modulus of elasticity

Flange pressure rating is
too low



Crush control
Stretch control
Low stress gasket
Gasket cut

Installation error in the
tools used to insert the gasket;
mishandling the gasket during
installation

Damaged gasket was not
inspected at installation

Provide gasket
handling instruction and
fixtures
Gasket disintegration


Incorrect gasket Material
Contamination of the
flange and/or gasket

Change gasket
material
Gasket blowout

Flange surface is too
smooth

Incorrect gasket material

Gasket is too thick

Machine
Gasket extrusion



Stretch control
Gasket control
Gasket is too soft; low
modulus of elasticity

Incorrect gasket material

Over torque
Procedure/Work Instruction/Job Note:
In-Service Flange Integrity Guideline
ConocoPhillips Indonesia
Failure Mode
ID-G-BU-00000-00000-01548 Rev. 2
Page 32 of 32
Cause

Corrective Actions
Gasket is too thick
Localized corrosion

Localized contamination of
the flange and/or gasket

Damaged surface

Generalized corrosion

Generalized contamination
of the flange and/or gasket

Incorrect gasket material

No gasket compression (not
seated for full
circumference)


Under torque
Gasket is too hard: high
modulus of elasticity

Gasket is too thin


Loose bolts on one end only



Pipe misalignment
Excessive pipe moments
Incorrect bolt up
procedure


All bolt loose


Bolt relaxation; bolt creep
Gasket relaxation; gasket
creep

Under torque


Random bolts loose

Incorrect bolt up
procedure

Bolt relaxation; if some low
yield bolts have been mixed
with the correct bolting


Bolts elongated




Renew sealing surface
Change gasket
material
Increase torque
Measure fastener
strength

Softer gasket
BOLT
Over torque
Incorrect bolting material
Gasket is too hard; high
modulus of elasticity
Align the pipe
Additional passes
Reestablish the load
Install spacers or
Belleville springs

Metal-to-metal contact
with controlled gasket
deflection
Additional passes
Vary the stretch
patterns
Revise assembly
procedure

New gasket
More detail about trouble shooting of flanged joint could be found in Appendix P of ASME PCC-1 (2010).
A series of diagnostic tables is provided with each dedicated to a specific type of leak event includes:
 Leak during Hydro Test (LHT)
 Leak during heat-up or initial operation (LIO)
 Leak corresponding to thermal or pressure upset (LCU)
 Leak after several months operation (LTO)
 Leak during shutdown (LDS)