ASME B31.3 INTERPRETATIONS NO. 17

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ASME B31.3

INTERPRETATIONS NO. 17

Replies to Technical InquiriesApril 1, 1998 Through November 31, 1999

General Information

It has been agreed to publish interpretations issued by the 831 Committee concerning 831.3 as partof the update service to the Code. The interpretations have been assigned numbers in chronologicalorder. Each interpretation applies to the Edition or Addenda stated in the interpretation, or if none isstated, to the Edition or Addenda in effect on the date of issuance of the interpretation. Subsequentrevisions to the Code may have superseded the reply.

These replies are taken verbatim from the original letters, except for a few typographical and editorialcorrections made for the purpose of improved clarity. In some instances, a review of the interpretationrevealed a need for corrections of a technical nature. In these cases, a revised reply bearing the originalinterpretation number with the suffix Ris presented.

ASME procedures provide for reconsideration of these interpretations when or if additional informationis available which the inquirer believes might affect the interpretation. Further, persons aggrieved byan interpretation may appeal to the cognizant ASME committee or subcommittee. As stated in theStatement of Policy in the Code documents, ASME does not "approve," "certify," "rate," or "endor~"

any item, construction, proprietary device, or activity.For detailed instructions on preparation of technical inquiries to the 831 Committee, refer to Appendix·Z.

Code Reference and Subject Indexes

Code Reference and Subject Indexes have been prepared to assist the user in locating interpretationsby location or by subject matter in the Code. They cover interpretations issued from Volume I up toand including the present volume, and will be updated with each volume.

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B31.3

Appendix V. Allowahle Variation in Elevated Temperature Service .Para. JIKI.2. Defining Piping Components .Pam. JOI.J. Design Tempenllures .Parol. 302.2.2. Listed Components Not Having 5pecilic Ratings .Parol. 302.2.4. Allowances for Pressure and Temperolture Variation , .Para. 302.3.5(c). Longitudinal Stress .Para. 302.3.5(dl. Limits of Calculation Stresses Due to Sustained Loads

and Displacement Strains .Parol. 304.3.3. Reinforcement of Welded 8ranch Connections .Parol. 322.3. Instrument Piping .Para. 323.1.1. Listed Materials .Pam. 323.1.2. Unlisted Materials and Unlisted Components for Metallic

Piping Lined With Nonmetals .Para. 323.1.2. Unlisted Materials .Pam. 331.1.3. Governing Thickness .Para. 331.1.3. Governing Thickness .Para. 335.1.1 (el. Alignment of Flanged Joints .Para. 335.2.3. Boll Length .Para. 340.4. Qualification of the Owner's Inspector .Parol. 345. Testing .Para. 345.2.3Ic). Special Provisions for Testing of Closure Welds ,Para. 345.1IIhl. Sensitive Leak Test .Para. 345.9.J<al. Allernative Leak Test Examination of Welds .Para. 345.9.I(h). Ahernative Leak Test Examination of Welds .Para. A322.6. Pressure Relieving Devices ' .Para. A3211.2.5(h)(I). Qualilication Test Pressure .Pam. K3IXl(a). Applicahility of High' Pressure Piping .Parol. 1014.2. Special Threaded Joints .Para. K3211.2.1 (a). Welding Qualilication Requirements .Tahle 302.3.4. Longitudinal Weld Joint Quality Factor .Tahle 341.3.2. Acceptance Criteria for Welds .Table 341.3.2. Acceptance Criteria for Welds ' .

Interpretation File No.

17-17 831-98-02617-23 B31·99-0I217-07 831-98-00617-11 831-98-01717-12 831-98-019A17-18 831·99~004

17-04 831-97-048 '

17-26 831-99-02217-24 831-99-01317-09 831-98-00917-08 831-98-008

17-01 831·97-04417·13 831-98-02017-21 831-99-01017-25 831-99-02017-20 831·99-00917-15 831-98-02317·30 B31·99-o2817-28 831-99-02517-02 831-97-04617-10 831-98-01117-05 831.97-04917·29 831-99-02717-06 831·98-00117-16 831-98-02517-19 831-99-00817-27 831·99-02417-14 831-98-02217-22 831·99-01117-03 831-97-047

199

831.3 Interpretations No. 17

Interpretation: 17-01

Subject: ASME B31.3b-1997 Addenda. Para. 323.1.2, Unlisted Materials

Date Issued: May 19, 1998

File: B31-97-044

17-01. 17-02. 17-03

Question (I): In accordance with ASME B31.3b-1997. does Table 300.1.1 apply to materials that arenot listed in Table A-I but are listed in ASME BPVC Section IX?

Reply (I): Yes.

Question (2): In accordance with ASME B31.3b-1997, does Table 331.1.1 apply to materials that arenot listed in Table A-I but are listed in ASME BPVC Section IX?

Reply (2): Yes, unless the provisions of para. 331.2.2 are satisfied.


Subject: ASME B31.3b-1997 Addenda. Para. 345.8(b), Sensitive Leak Test


File: B31-97-046

Question: In accordance with ASME B31.3b-1997, para. 345.8(b), must the test pressure for a sensitiveleak test be greater than 15 psi?

Reply: No.


Subject: ASME B31.3b-1997 Addenda, Table 341.3.2. Acceptance Criteria for Welds


File: B31-97-047

Question: In accordance with ASME B31.3b-1997, Table 341.3.2. is the maximum allowable height ofreinforcement or internal protrusion. in any plane through the weld. listed in "L" for each face of the ~eld?

Reply: Yes. See also Interpretation 9-04.

201

17-04. 17-05. 17-06 B31.3 Interpretations No. 17


Subject: ASME 831.3b-1997 Addenda, Para. 302.3.5(d), Limits of Calculation Stresses Due to SustainedLoads and Displacement Strains


File: 831-97-048

Question (I): In accordance with ASME 831.3b-1997, para. 302.3.5(d), may the number of cycles, Nj ,

in Equation (I d) exceed 2,000,000 cycles?

Reply (I): Yes; however, see also Note (5) of Equation (Ic) for limits on the equivalent number of fulldisplacement cycles, N.

Question (2): In accordance with ASME 831.3b-1997, para. 302.3.5(d), Equation (Id), is it required tocombine thermal displacement cycles with displacement cycles due to other conditions such as wave motion.

Reply (2): Yes.


Subject: ASME 831.3-1996 Edition, Para. 345.9.1 (b), Alternative Leak Test Examination of Welds


File: 831-97-049

Question: In accordance with ASME 831.3-1996 Edition, para. 345.9. I(b). may the liquid penetrantmethod be used to examine a weld on a magnetic material?

Reply: Yes.


Subject: ASME 831.3-1996 Edition; Para. A328.2.5(b)( I), Qualification Test Pressure


File: 831-98-001

Question: In accordance with ASME 831.3-1996 Edition, can the pressure design thickness be usedinstead of the nominal thickness in Equation (27) of para. A328.2.5(b)(I), to calculate the qualificationpressure?

Reply: No.

202

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B31.3 Interpretations No. 17


Subject: ASME 831.3b-1997 Addenda; Para. 301.3. Design Temperatures

Date Issued: May 19. 1998

File: 831-98-006

17-07. 17-08. 17-09

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Question: In accordance with ASME 831.3b-1997. para. 301.3. should fire case temperature or pressuresbe considered to satistY, the requirements of para. 301.2. in establishing the design conditions of pipingthat may be exposed to an accidental fire?

Reply: The Code does not require the consideration of accidental fire cases when establishing the pipingdesign conditions. except as required to meet the pressure relief requirements of para. 322.6.3. See alsopara. 300(c)(5).


Subject: ASME 831.3-1996 Edition. Para. 323.1.2. Unlisted Materials and Unlisted Components for MetallicPiping Lined With Nonmetals


File: 831-98-008

Question (I): In accordance with ASME 831.3-1996 Edition. may unlisted metallic materials be usedin the manufacture of metallic piping components lined with non-metals?

Reply (I): Yes. See para. A323.1.

Question (2): In aC,cordance with ASME 831.3-1996 Edition. may pressure containing metallic pipingcomponents (lined with non-metals). not manufactured in accordance, with a listed standard and for whichthe rules in para. 304 (other than para. 304.7.2) do not apply. be qualified for use under this Code?

Reply (2): Yes. See paras. A300(d) and 304.7.2.


Subject: ASME 831.3b-1997 Addenda. Para. 323.1.1. Listed Materials


File: 831-98-009

Question (I): In accordance with ASME 831.3b-1997. are classes 12. 13.22. and 23 of ASTM A 671.A 672. and A 691 the only listed materials in the Code for these specifications?

Reply (I): Yes.

Question (2): Is it a requirement that listed pipe and tube materials in ASME 831.3 be hydrotested bythe manufacturer? .

Reply (2): Yes. See the requirements of the listed specifications and Note (76) of Appendix A.

203

17-10. 17-11. 17·12 831.3 Interpretations No. 17


Subject: ASME B31.3b-1997 Addenda, Para. 345.9.1 (a), Alternative Leak Test Examination of Welds


File: B31-98-0I I

Question: In accordance with ASME B31.3b-1997, para. 345.9. I(a), is 100% UT examination an acceptable substitute for 100% radiography?

Reply: No.


Subject: ASME B31.3b-1997 Addenda, Para. 302.2.2, Listed Components Not Having Specific Ratings

Date Issued: November II, 1998

File: B31-98-0 17

Question: In accordance with ASME B31.3b-I997, if a fitting is manufactured to ASME B16.9 and alisted material specitication that includes a reference to Note (16) of Appendix A, may the user establishthe pressure-tempenllure rating in accordance with para. 302.2.2, without applying a weld joint qualityfactor in accordance with para. 302.3.4?

Reply: Yes.


Subject: ASME B31.3b-1997 Addenda, Para. 302.2.4, Allowances for Pressure and Temperature Variation'

Date Issued: November I I, 1998

File: B3I-98-019A

Question ( I): In accordance with ASME B3 I.3b-I997, para. 302.2.4, are the allowable variations permittedin this paragraph only applicable when the increased pressure is less than or equal to the test pressure usedin accordance with para. 345'!

Reply (1 ): Yes.

Question (2): When establishing the maximum allowable relieving pressure permitted in accordance withpara. 322.6.3(c), may the test pressure used in accordance with para. 345 be exceeded?

Reply (2): Yes, provided the maximum relieving pressure requirements of ASME BPVC Section VIII,Division I are met?

204

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Subject: ASME B31.3b-1997 Addenda, Para. 331.1.3, Governing Thickness


File: B31-98-020

17-13. 17-14

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Background IQuestion (1)/: An integrally-reinforced branch connection fitting is welded externally tq apipe that has a wall thicker than the minimum material thickness requiring PWHT, and the branch pipehas a wall thickness thinner than the minimum material thickness requiring PWHT.

Question (1 a): In accordance with ASME B3 1.3b- I997, does the thickness of the branch pipe attachedto the branch connection fitting have any effect on whether the weld between the branch connection andthe main pipe requires PWHT?

Reply (I a): No.

Question (I b): Does the weld throat thickness between the branch connection fitting and main pipe haveany effect on whether this joint requires PWHT?

Reply (Ib): Yes. See para. 33 I. l.3(a).

Question (I c): Does the thickness of the branch connection fitting have any effect on whether this jointrequires PWHT?

Reply (Ic): No. See para. 33 I. l.3(a).

Question (2): In accordance with ASME B3 I.3b- I997, para. 331.13, if the header has a wall thicknessless than the minimum material thickness requiring PWHT, would the deciding factor for carrying outPWHT be whether the throat thickness of the joint is greater than twice the minimum material thicknessrequiring PWHT?

Reply (2): Yes.


Subject: ASME B31.3-I993 Edition, Table 302.3.4, Longitudinal Weld Joint Quality Factor


File: 831-98-022

Question: In accordance with ASME 831.3-1993 Edition, is it permissible to increase Ej for ASTMA 312 EFW pipe to 1.00 by 100% radiography?

Reply: Yes. See Table 302.3.4.

205

17-15. 17-16 831.3 Interpretations No. 17


Subject: ASME B31.3b-1997 Addenda, Para. 340.4, Qualification of the Owner's Inspector


File: B31-98-023

Question: In accordance with ASME B31.3b-1997, may the owner's inspector and the installing contractor's examiner both be employed by the same organization?

Reply: Yes, provided all requirements of para. 340.4 are met.


Subject: ASME B31.3b-1997 Addenda, Para. K3OO(a), Applicability of High Pressure Piping


File: B31-98-025

Question (I): In accordance with ASME B31.3b-1997, para. K3OO(a), is it mandatory that the owner ofa piping system designate it as being in High Pressure Fluid Service in accordance with Chapter IX whenthe system pressure exceeds that allowed by ASME B16.5, PN 420 (Class 2500) rating?

Reply (I): No.

Question (2): In accordance with ASME B31.3b-1997, para. K3OO(a), can piping be designated by theowner as being in High Pressure Fluid Service in accordance with Chapter IX and be designed to ChapterIX, even if this results in a wall thickness that is less than that required by design in accordance withChapters I through VI?

Reply (2): Yes; however, when piping is so designated, Chapter IX shall be applied in its entirety.

206

831.3 Interpretations No, 17 17-17. 17-18

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Subject: ASME B31.3b-1997 Addenda, Appendix V, Allowable Variation in Elevated Temperature Service

Date Issued: November II, 1998

File: B31-98-026

Question (I ): In accordance with ASME B31.3b-1997, when evaluating variations in elevated temperatureservice in accordance with Appendix V, must the design temperature established in accordance with para.301.3 be high enough such that the corresponding allowable stress value in Table' A-I !s based on creepcriteria?

Reply (I): No; however, if the maximum temperature experienced during the variations is where thecreep properties control design, Appendix V applies. Note that the word "design" in para. V302(c) doesnot apply and will be deleted by errata from a future edition of the Code.

Question (2): When some varying conditions are below the creep range and some are in the creep range,does ASME B31.3b-1997, Appendix V require that conditions below the creep range be included in thecalculation of the usage factor in accordance with para. V303.~'?

Reply (2): No. See para. V302(c).

Question (3): In accordance with ASME B31.3b-1997, when determining if Table A-I allowable stressvalues are based upon creep criteria, may the maximum temperature in Tables 2A or 2B of ASME BPVCSection II, Part D be used as the highest temperature, which is below the range of values based upon thecreep criteria?

Reply (3): Yes. See Footnote 2 to para. 302.3.2.


Subject: ASME B31.3c-1998 Addenda, Para. 302.3.5(c), Longitudinal Stress

Date Issued: July I, 1999

File: B31-99-004

Question (I): Shall longitudinal stresses due to the misalignment of piping during assembly, or intentionalcold spring, be included as a longitudinal sustained stress in accordance with para. 302.3.5(c)?

Reply (I): No.

Question (2): Is it required to include the stresses due to misalignment of piping during assembly orintentional cold spring in the calculation of displacement stress range in accordance with para. 319.2.3?

Reply (2): No. See para. 319.2.I(c).

Question (3): Shall axial stresses due to the imposed displacements be considered in the evaluation ofthe displacement stress range'?

Reply (3): Yes. See para. 319.2.3(c).

207

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17-19, 17-20, 17-21


Subject: ASME B31.3-1996 Edition. Para. K314.2. Special Threaded Joints

Date Issued: July I. 1999

File: B31-99-oo8


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Question (I ): In accordance with ASME B31.3-1996 Edition. is a hammer union. whose male and femaleends are butt welded to the piping. considered a Special Threaded Joint as defined in para. K314.2?

Reply (I): No.

Question (2): In accordance with ASME B3 I.3- I996 Edition. can a threaded joint that does not meetthe requirements of para. K314.2 be qualified Jor High Pressure Fluid Service in accordance with therequirements of para. K304.7.2?

Reply (2): Yes. provided the requirements of para. K3I4.3 are also met.


Subject: ASME B3 I.3c- I998 Addenda. Pam. 335.2.3. Bolt Length


File: B31-99-009

Question: In accordance with ASME B31.3c-1998. Para. 335.2.3. if a bolt fails to extend beyond its nutand no more than one thread is visible inside the nut. is the bolt considered acceptably engaged?

Reply: Yes.


Subject: ASME B31.3c-1998 Addenda. Para. 331.1.3. Governing Thickness


File: B31-99-010

Question: In accordance with ASME B31.3c-1998. pam. 331.1.3. if the thicker of two components ismachined before welding. in accrodance with pam. 328.4.2. to match the thickness of the thinner component.is the resulting matching thickness at the weld joint used in determining the requirements for PWHT?

Reply: Yes.

208



Subject: ASME B31.3c-1998 Addenda. Table 341.3.2. Acceptance Criteria for Welds


File: B31-99-0 II

17-22, 17-23, 17-24

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Question (I): In accordance with ASME B31.3c-1998. Table 341.3.2. is surface porosity acceptable onthe crown or external surface of a groove weld that is greater than Y'c> in. in nominal thickness'!

Reply (I): Yes.

Question (2): In accordance with ASME B3I.3c-1998. Table 341.3.2. is surface porosity acceptable onthe crown of a 14 in. fillet weld'?

Reply (2): Yes.


Subject: ASME B31.3c-1998 Addenda. Para. 300.2. Defining Piping Components


File: B31-99-012

Question: In accordance with ASME B31.3c-1998. are pressure containing components such as strainers.filters. knock-out pots. holding pots and other devices that serve such purposes as mixing. separating.snubbing. distributing. and metering or controlling flow included in the scope of this Code?

Reply: Yes. unless the Owner specifies another code. See definition of "piping components" (para.300.2)


Subject: ASME B31.3c-1998 Addenda. Panl. 322.3. Instrument Piping


File: B31-99-0 13

Question: In accordance with ASME B31.3c-1998. are instrument piping components (such as' tubing.compression fittings. barstock valves. etc.) outside of a piping isolation valve (piping root valve) withinthe scope of ASME B3 I.3'!

Reply: Yes. See para. 322.3.

209

17-25, 17·26, 17-27


Subj~ct: ASME 831.3-1996' Edition, Para. 335.1.1 (c), Alignment of Flanged Joints

Date Issued: November 16, 1999

File: 831-99-020


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Question (I): In accordance with ASME 831.3-1996 Edition, para. 335.1.1 (c), does the specified toleranceapply to each individual flange, measured to the design plane, or to the total misalignment between twomating flanges?

Reply (I): It applies to each individual flange, measured to the design plane.

Question (2): In accordance with ASME B31.3-.1996 Edition, para. 335. 1.1 (c), do the requirements applyto all pipe sizes and pressure rating classes?

Reply (2): Yes.


Subject: ASME 831.3-1999 Edition, Para. 304.3.3, Reinforcement of Welded Branch Connections


File: 831-99-022

Question: In accordance with ASME 831.3-1999 Edition, can the rules in para. 304.3.3 be used for thepressure design of a Tee, machined from stock with a remaining block shape, that does not confonn to alisted standard?

Reply: Yes; however, see paras. 304.3.5 and 300(c).


Subject: ASME B31.3-1999 Edition, Pam. K328.2.1 (a), Welding Qualification Requirements


File: 831-99-024

Question: In accordance with ASME 831.3-1999 Edition, para. K328.2.1 (a). must the perfonnancequalilication test coupons for each welder and welding operator be impact tested?

Reply: Yes.

210

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831.3 Interpretations No. 17 17·28. 17-29. 17-30

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Subject: ASME B31.3- i999 Edition, Para. 345.2.3(c), Special Provisions for Testing of Closure Welds


File: B31-99-025

Question (I): Does ASME B31.3-1999 Edition, para. 345.2.3(c) require that the described examinationsbe performed for closure welds connecting piping systems or components that have been successfully testedin accordance with para. 345?

Reply (I): No. The weld may be leak tested in accordance with para. 345.1 instead.

Question (2): Can weld connecting a flange to a piping system be considered a closure weld?

Reply (2): Yes, but if the weld is to be examined in accordance with para. 345.2.3(c), the flange, as wellas the piping system must have been successfully tested.


Subject: ASME B31.3-1999 Edition, Para. A322.6, Pressure Relieving Devices


File: B31-99-027

Question: Are pressure relieving devices installed in accordance with ASME B31.3- I999 Edition, para.A322.6 required to meet ASME BPVC Section VIII, Division I, UO-136(b)(3)?

Reply: Yes.


Subject: ASME B31.3-1999 Edition, Pam. 345, Testing


File: B31-99-028

Question: In accordance with ASME B31.3-1999 Edition, para. 345, may the test pressure exceed themaximum allowable internal pressure, P"" for a miter bend in accordance with para. 304.2.3? .

Reply: Yes.

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ASME B31.3 INTERPRETATIONS NO. 17