AGENDA ITEM 653-258 REV 02 (11-13-12) TEMPERATURE LIMIT MIXED MATERIAL TANKS
TITLE:
Inspection and repair of Appendix SC mixed material tanks (carbon steel, duplex stainless & austenitic
stainless steel)
SOURCE:
Stainless Steel Task Group (SSTG) list of working items from November 9, 2009 meeting agenda and
minutes, formal inquiry 653-2011-F1 dated February 13, 2011 regarding 200º F temperature limits in 653
e4 A1 and an informal email inquiry regarding 200º F temperature limit to a member of the SSTG on
February 13, 2011.
PURPOSE:
Address the inspection and repair of Appendix SC tanks and other mixed material tanks based on the
latest revisions to the design standard to permit temperature limits greater than 200º F.
CONTACT:
John F. Fumbanks
Pond & Company
3500 Parkway Lane. Suite 600
Norcross GA. 30092
Tel: 678-336-7740 x4721
Cell 678-525-3432
Fax: 678-336-7744
E-mail: fumbanksj@pondco.com
COST EFFECT: Use of the proposed Appendix may save Owners money by facilitating economical, long life tanks by the
use of corrosion resistant materials where they are needed.
TECHNICAL BASIS: The Stainless Steel Task Group has provided guidance for the technical design parameters
included in the document based on the group’s collective design and construction experience.
PROPOSED CHANGE:
Provide for the revision of Appendix SC SC.4.2 of API 653e4 A2 to provide for inspection, repair, alteration and
reconstruction of mixed material tanks with design temperature exceeding 40oC( 100oF) but less than 260oC (500oF).
Paragraph references are for API 653e4A2 and API 650e11A3.
HISTORY: This appendix follows a pattern of the SCAST to modify the API 653 standard to reflect the latest materials
allowed in construction of new API 650 tanks.
Rev 0 Deleted text = text
Rev 0 New text = text
Rev 1 (As presented at the SGF F12) Deleted text = text
Rev 1 (As presented at the SGF F12) New text = text
Rev 2 (As modified at the SGF F12) Deleted text = text
APPENDIX SC—STAINLESS AND CARBON STEEL MIXED MATERIALS STORAGE TANKS
SC.4 Suitability for Service
SC.4.1 Add to 4.2.4.1: The requirements of API STD 650, Sections S.3.5 and API STD. 650, and X.3.6, shall also be satisfied for the
stainless steel components of the tank.
SC.4.2 Add to Revise 4.2.4.3: This appendix applies only to tanks in non-refrigerated services with a maximum design temperature
not exceeding 93 260C (200 500F). Mixed material tanks operating at temperatures greater than 93C (200F) are not addressed in
this appendix except for tanks covered in SC.4.3 below. For the purposes of this appendix, the design temperature shall be the
maximum design temperature as specified by the Purchaser Owner/Operator.
Note: Exothermic reactions occurring inside unheated storage tanks can produce temperatures exceeding 40C (100F).
SC 4.3 Tanks containing mixed materials which do not meet the temperature limitations specified in SC.4.2, but have a successful
service history of operation, shall be evaluated for thermal differential expansion at mixed material interface in order to remain in
continued service. This analysis shall be performed in accordance with API 650 Appendix SC, Section SC.3 and by an engineer
experienced in storage tank design and evaluation methodologies. If no accounting for differential expansion effects in prior design
work is documented, then such effects shall be evaluated at the time of existing tank assesment