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.
The 2014 edition requires that thermowells comply with ASME PTC 19.3 TW.
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.
The 2014 edition added requirements for and illustrations of welds for integrally reinforced branch connections.
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.
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.
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.
- 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.