ASME B31.8 INTERPRETATIONS VOLUME 13 Replies to Technical Inquiries July 2001 Through December 2003 Interpretations 13-1 Through 13-8 It has been agreed to publish intepretations issued by the B31 Committee concerning B31.8 as part of the update service to the Code. The interpretations have been asssigned numbers in chronological order. Each interpretation applies either to the latest Edition or Addenda at the time of issuance of the interpretation or the Edition or Addenda stated in the reply. Subsequent revisions to the Code may have superseded the reply. These replies are taken verbatim from the original letters, except for a few typographical and editorial corrections made for improved clarity. ASME procedures provide for reconsideration of these interpretations when or if additional information that the inquirer believes might affect the interpretation is available. Further, persons aggrieved by an interpretation may appeal to the cognizant ASME committee or subcommittee. As stated in the Statement of Policy in the Code documents, ASME does not "approve," "certify," "rate," or "endorse" any item, construction, proprietary device, or activity.
Subject Paras. 823.21.824.1.825.1. and 825.2... Para 831.22(d). Bolting... Para 831.4l(d).... Para. 833... Paras. 841.321.841.33. and 852.51... Para. 854.4@)(2).... Appendix F. Fig. F5... Code Conformance... Interpretation 13-7 13-5 13-2 13-1 13-6 13-4 13-8 13-3
Subject: ASME B31.8, Para. 833 Date Issued: August 11,2000 Pile: B31-00-002 Question (1): Does para. 833.4(b) require that the longitudinal stress due to internal pressbe calculated using the pressure design equation in para. 841.11? Reply (1): No. Question (2): Does para. 833.2 require that stresses due to weight of the pipe be combined with stresses due to thermal expansion? Reply (2): No. Question (3): Does para. 833.4 apply to a fully restrained section of pipeline? Reply (3): No. Question (4): Does para. 833.4 limit the thermal expansion stress range to 0.72 SMYS, the sum of longitudinal stresses due to pressure and weight to 0.75 SMYS, and the sum of the thermal expansion stress rqnge and the longitudinal stresses due to pressure and weight to 1.0 SMYS? Reply (4): Yes. Question (5): Do we need to consider the longitudinal joint factor E in the calculation of allowable hoop stress for offshore pipelines as specified in para. 841.11 for onshore pipelines? Reply (5): No. Question (6): Can a hoop stress design factor of 0.80 be used for an offshore pipeline design? Reply (6): No. Subject: ASME B31.8, Para. 831.41(d) February 14,2002 C> File: B31-99-032 Question: Where the diameter of the finished opening for a branch connection is smaller than the inside diameter of the branch pipe, is it permissible to include as available reinforcement excess thickness in the header wall located between the finished opening and the branch wall. Reply: Yes.
Interpretation: 13-3 Subject: ASME B31.8 Code Conformance of Pikotek Flanges Date Issued: March 21,2003 File: B31-01-005 Question: In order to comply with the Code requirements of ASME B31.8, is it permissible to use Pikotek gaskets as unlisted components in standard B16.5 flanges and operate at higher working pressures and temperatures than those listed in ASME B16.5-1996 (Tables 2 listed under Pressure-Temperature Ratings) provided the calculated flange (and bolt) stresses remain below the allowable stresses outlined in the applicable ASME Boiler and Pressure Vessel Code (as specifically detailed in memorandum titled "Code Conformance of Pikotek Flanges" dated April 7, 1997)? Reply: No. Interpretation: 13-4 Subject: ASME B31.8-1999, Para. 854.4@)(2) Date Issued: May 8, 2003 File: 02-3705 Question: Is it mandatory, per para. 854.4@)(2) that additional sectionalizing block valves be installed to conform to the spacing requirements in para. 846.11, when one mile or more of transmission line is replaced to maintain the established MAOP in conjunction with a change in location class? Answer: No. Interpretation: 13-5 Subject: ASME B31.8, Para. 831.22(d), Bolting Date Issued: May 15, 2003 Item: B31-01-004 (formerly B31-00-003) Question (1): Do ASTM A 563 nuts meet the requirements set forth in para. 831.22(d) for use with ASTM A 307 bolts? Reply (1): No. As written, only ASTM A 194 or A 307 may be used. However, per para. 811.22, other materials may be qualified for use as described in para. 811.221 or para. 811.222. Question (2): If ASTM A 563 nuts meet the requirements set forth in para. 831.22(d), are Grade A, Heavy Hex nuts required to match ASTM A 307 Grade B bolts? Reply (2): See Reply 1. Interpretation: 13-6 Subject: Appendix F, Fig. F5, Definition of dimension L Date Issued: September 21,2003 File: 03-155 Question: If the L dimension for a welded-on fitting (integrally reinforced) lies entirely within the fitting, then for the purposes of extra area replacement per para. 831.41(e), is L then equal to 2?4H, where H is the nominal wall thickness of the header? Reply: Yes, provided 2 % is ~ smaller than 2 %~ + M.
Interpretation: 13-7 Subject: Paras. 823.21, 824.1, 825.1, and 825.2 Date Issued: September 28,2003 File: 03-154 Question (1): Is it mandatory that welds in all carbon steels be stress relieved when the wall thickness exceeds 1% in. even if hardness requirements have been achieved without stress relieving? Reply (1): Yes, ASME 831.8 para. 825.2 requires carbon steel welds shall be stress relieved when the nominal wall thickness exceeds 1% in. Question (2): Is preheating mandatory for carbon steels having a carbon content less than 0.32% or a carbon equivalent (C + 1/4 Mn) less than 0.65%? Reply (2): No, unless the weld procedure requires such treatment to produce satisfactory welds. Question (3): Is stress relieving mandatory for carbon steels having a carbon content less than 0.32% or a carbon equivalent (C + '/4 Mn) less than 0.65%? Reply (3): No, provided all of the other requirements are met. Question (4): If a'weld procedure for sour gas service is qualified under ASME para. D( and the procedure meets the hardness requirements as specified in NACE MR0175 without preheating and stress relieving are preheating and stress relieving still requid under ASME B31.8 paras. 824.1 & 825.2? Reply (4): Yes, para. B801 indicates that "if a paragraph appearing in Chapters I through VII does not have a corresponding paragraph in this chapter, the provisions apply to sour gas service without modification." Interpretation: 13-8 Subject: Pipe bend at 30% SMYS or greater, Paras. 841.321, 841.33, and 851.51 Date Issued: October 21,2003 File: 02-3938 Question: Does ASME B31.8 address field bending of pipe after hydrostatic testing? Reply: No.