ASME B31.3 – Substantive Changes to 2014 Edition

ASME B31.3 – Substantive Changes to 2014 Edition

ASME_B31-1.png

In addition to the many clarifications, updated references to codes and standards, updates to basic allowable stresses, and added listed materials, there are several substantive changes to the 2014 Edition of ASME B31.3, Process Piping.

These changes are:

Category M Fluid Service

The definition was revised in the 2014 edition to provide better guidance on selection of the Category M Fluid Service designation

(b) Category M Fluid Service:  A fluid service in which all of the following apply:

(1) The fluid is so highly toxic that a single exposure to a very small quantity of the fluid caused by leakage, can produce serious irreversible harm to persons on breathing or bodily contact, even when prompt restorative measures are taken; and

(2) If after consideration of piping design, experience, service conditions, and location, the Owner determines that the requirements for Normal Fluid Service do not sufficiently provide the leak tightness required to protect personnel from exposure.

Flared laps are prohibited for use in Category M fluid service in the 2014 edition.

Allowable Stress Range

The 2014 edition explicitly requires that the maximum value of SL considering all conditions be used in calculating the allowable stress range.

Thermowells

The 2014 edition requires that thermowells comply with ASME PTC 19.3 TW.

Cold Spring

The 2014 edition requires that when cold spring is used, the reactions be computed both with the assumption that only two-thirds of the design cold spring is present, and with four-thirds of the design cold spring present.

Impact Testing of Carbon Steels

The 2014 edition restricted the use of Fig.  323.2.2B to provide a further basis for the use of carbon steels without impact testing.  It may not be used for:

  • Piping in elevated temperature service
  • Piping that is expected to experience shock loading or thermal bowing
  • Piping that contains welds between dissimilar materials

The Code warns that the calculation of stresses due to cold springing or misalignment should be included as part of the stress ratio.

Weldolets

The 2014 edition added requirements for and illustrations of welds for integrally reinforced branch connections.

Preheat

The 2014 edition revised the preheat requirements somewhat.  This revision, along with revisions to ASME B31.1, makes the preheat requirements in the two Codes the same.

Heat Treatment

The 2014 edition significantly revised the heat treatment requirements.  This revision, along with significant revisions to ASME B31.1, makes the heat treatment requirements in the two Codes the same.

Examination Personnel

The 2014 edition added specific examination personnel qualification requirements, which are those described in ASME B&PV Code, Section V.  The qualifications:

  • Shall be in accordance with the employer’s written practice and
  • Must be in accordance with one of the following documents
  • SNT-TC-1A, Personnel Qualification and Certification in Nondestructive Testing
  • ANSI/ASNT CP-189, ASNT Standard for Qualification and Certification of Nondestructive Testing Personnel

National or international central certification programs, such as the ASNT Central Certification Program (ACCP) or ISO 9712:2012-based programs, may be alternatively used to fulfill the training, experience, and examination requirements of the documents listed above.

Magnetic Particle and Liquid Penetrant Examinations

The 2014 edition added specific acceptance criteria for magnetic particle and liquid penetrant examination.

Hydrotest

  • The 2014 edition permits the hydrotest pressure to be lowered to the design pressure while examining for leaks.
  • The 2014 edition simplified the calculation of hydrotest pressure.

High Pressure Piping

The 2014 edition changed the leak test pressure from 1.5 times the design pressure corrected for temperature to 1.25 times the design pressure corrected for temperature.

Alternative Rules for Evaluating Stress Range

Because of the potential for misapplication of the alternative rules, and because many of the provisions of Appendix P had been incorporated into the base Code, Appendix P was removed in the 2014 edition.

 

   Click to Request Info from Becht

 

Tags: ,
|

About The Author

Contact:
Mr. Frikken is an internationally recognized authority in piping systems, valves, and the development of standards and specifications. His work with Becht includes designing new piping systems, analyzing existing piping systems, assisting manufacturers with respect to code compliance issues, and providing instruction on process piping and piping flexibility analysis courses. Don has received a number of awards including most recently the ASME J. Hall Taylor Medal for his distinguished service and eminent achievement, the ASME B31 Forever Medal for Excellence in Piping, and the ASME Melvin R. Green Codes and Standards Medal in 2002, which recognizes outstanding contributions to the development of documents used in ASME programs of technical codification, standardization and certification. He received the ASME Fellow Award in 1994 and the ASME Dedicated Service Award in 1995. Prior to joining Becht Engineering, Don spent 34 years with Solutia, Inc. and Monsanto Company working on a wide range of activities including piping and mechanical design, project engineering, and engineering standards. Mr. Frikken is a registered PE in Missouri.

Authors Recent Posts

ASME B31.3 – Substantive Changes to 2014 Edition

27 thoughts on “ASME B31.3 – Substantive Changes to 2014 Edition

  1. I’m not sure what is meant by “codes exam”. B31.3 says it is effective six months after it is published, but a different date can be selected by contracting parties.

  2. In the 2014 edition of B31.3, the hydrotest pressure is still 1.5 times the design pressure corrected for temperature. The way the correction for temperature is made is simplified from the 2012 edition and will result in lower test pressures for many piping systems.

  3. Regarding PWHT requirements for welds through branches:

    In previous versions of the code (2012 and earlier): Heat treatment is required when the thickness through the weld was twice the minimum material thickness requiring heat treatment. So if P1 materials, if the thickness through the weld was greater than 1.5″ (=2*0.75″), then PWHT was required.

    In the 2014 version of the code, Para 331.1.1 states PWHT per Table 331.1.1 except as provided in Table 331.1.2 and Table 331.1.3. For P-1 Groups 1-3 materials, Table 331.1.1 states PWHT required (for all thicknesses); but this is exempted by Table 331.1.3, as long as a preheat of 95 C is applied on materials greater than 25 mm, and that multi layer welds used for materials greater than 5 mm.

    My questions regarding branch welds are:
    1) what thickness are we comparing the thickness through weld value (calculated in Para 331.1.3(b)(5) to) to see if PWHT is required? (In 2012, this value was compared against twice the material thickness requiring heat treatment in Table 331.1.1).
    2) whether or not Table 331.1.3(2014) exemptions can be applied to the thickness through the weld of branch connections. If so, does the additional preheat requirement apply to any thickness through welds greater than 25 mm?

  4. Dear Sir,
    As you dictates in your blog 2014 edition of ASME B31.3, Appendix-P has been removed and because many of the provisions of Appendix-P had been incorporated in based code….

    means it relates to max. value of SL considering all conditions be used in calculating the allowable stress range in following manner;

    SA = f {1.25 (Sc + Sh) – SLmax.}

    where,
    SL as calculated in below conditions & SLmax. to be used in above eqn. out of following;

    SLi) Primary Sustained Stress @ cold condition of piping

  5. SLi) Sustained Stress @ cold condition of piping n of piping from supports i.e. HOT to COLD condition y confirm whether allowable basis as considered for above each conditions are correctly taken or not?

  6. 1) In my opinion, you are comparing the calculated thickness in para. 331.1.3(b)(5) to the control thickness. So for P1 materials, you would be comparing it to the 25 mm in Table 331.1.3.
    2) In my opinion, in order to use the exemption for heat treatment of P1 materials described in Table 331.1.3, the 95 C preheat has to be applied for any welds with a control thickness greater than 25 mm.

  7. 1) In my opinion, you are comparing the calculated thickness in para. 331.1.3(b)(5) to the control thickness. So for P1 materials, you would be comparing it to the 25 mm in Table 331.1.3.
    2) In my opinion, in order to use the exemption for heat treatment of P1 materials described in Table 331.1.3, the 95 C preheat has to be applied for any welds with a control thickness greater than 25 mm.

  8. I’m not sure I understand your question, but I will try an explanation and you can ask again if what I say does not help.

    SL for use in this equation is normally caulated using just weight and pressure loads. Occasional loads such as wind, earthquake and water hammer are normally excluded. SL can vary when the piping is alternately filled with liquid and gas, and it can vary when the piping grows up off of a support in the hot condition. In my opinion, the Code now requires that you calculate the maximum value of SL for all of these expected condition, and use that value when you calculate SA.

  9. Thanks for your prompt response.
    Your explanation is definitely going to help. But I would have further more questions;
    Up till now we had evaluated SL using just weight and pressure loads and compared w.r.t. Sh (Hot Allowable stresses).
    Like in similar manner whether hot sustained SL (when the piping grows up off of a support in hot condition) needs to calculate first and to be compared with SA (Thermal Allowable stress range) or Sh (Hot Allowable stresses) prior to use in Liberal Allowable limits as SLmax?

  10. When we did these calculations using less sophisticated methods than are available today with the various computer programs, we did calculated SL first, then we calculated SA, then calculated SE. The use of the “conservative” allowable stress range became popular because it simplified the calculation of SA and we could evaluate SL and SE separately. With today’s computer programs, SL, SA and SE are calculated at the same time at every point in the piping system. The complicating factor with the new requirement is that a single case (weight + pressure + thermal + displacement) for the maximum SL and the maximum SE must be input in order to get a complete picture from the computer program output when using the “liberal” allowable stress range.

  11. You posted that the 2014 edition requires that thermowells comply with ASME PTC 19.3 TW, however I haven’t been able to find such a passage. Where can I find this in the code?

    kind regards,

    Walter

  12. It is para. 306.6. It says: Thermowells shall comply with ASME PTC 19.3 TW where applicable.

  13. Thanks, I have been looking in the B31.1 instead of the B31.3. For some mysterious reason a check against PTC193. TW-2010 is not mandatory for power piping.

  14. I can´t find the hardness limits for welds in 2014 Edition of B31.3. Also paragraph 331.1.7 is missing.
    Is there any adenda to the 2014 edition?

  15. There will be no addenda…we don’t do that anymore. I expect it will be corrected in the 2016 edition. There are no limits in the 2014 edition.

  16. I have just one query regarding the Post Welding Heat Treatment as per ASME B31.3_2014, what is the minimum thickness for PWHT in Carbon Steel (P number 1 all groups) .
    The code indicates the Table 331.1.1 which actually gives us the Holding Temperature Range and time per the thickness. Can you please give me the right direction (table) to find this statement?

  17. The 2014 edition does not require heat treatment of P No. 1 materials for any thickness if the material is preheated to 95 C and multipass welding is employed. See Table 331.1.3.

  18. Hi Don,

    If my flare header (SA333) metal temperature becomes colder from amb. temp (e.g. 0C or -45C) to -45 in 30 to 40 seconds, is this a thermal shock?

    What is the exact definition of thermal shock?

    Thanks
    MJ

  19. You discovered a problem with what we did. There is no definition in the 2016 edition. We did better with a revision that will be included in the 2018 edition. In order to use the figure, the 2018 edition says “local stresses caused by shock loading, thermal bowing and differential expansion between dissimilar metals are less than ten percent of the basic allowable stresses at the condition under consideration.”

  20. Thanks Don for prompt respond.
    Right now my case is dealing with ed 2016. In reality I’m dealing with a cooling rate of 0.65 to 0.80 C/sec. Does this mean “Thermal Shock Loading” per current revision of the code? If YES,I have to use SS instead of CS?

    Thanks
    MJ

  21. Since the Code does not define thermal shock, it is up to you to decide whether or not 0.65 to 0.80 C/sec is thermal shock. Depending on the way heat is transferred from the pipe material to the fluid, changing to stainless steel may make the potential problem worse.

  22. High amount of gas will be released from PSV discharge to the flare. JT effect will decrease the CS metal temp. to -95C. Then gas will cool off the CS.

Comments are closed.

Let Becht Turn Your Problem
Into Peace of Mind