Permission to determine pressure-temperature ratings in accordance with themethod set forth in ASME B16.34 wasdeleted.
UNLISTED VALVES (PARA. 307)
The ASME B31.3 Process Piping Standard provides requirements forpiping, including materials and components, design, fabrication,assembly, erection, examination, inspection and testing of piping.
SAI Global Australia Pty Ltd ABN 14 144 974 087
The approach to calculating flexibility factorsand stress intensification factors for branchconnections was changed. There aredefinitions for in-plane, out-plane, and torsionmoments on both the run and branch legs.Branch leg calculations use the appropriatebranch flexibility and stress intensificationfactors and run leg calculations use theappropriate run factors.
FLEXIBILITY AND STRESSINTENSIFICATION FACTORS (PARAS. 319& 320)
Appendix D, Flexibility and StressIntensification Factors, which providedmethods for calculating the factors, wasremoved. The 2020 edition refers to ASMEB31J, Stress Intensification Factors (i-Factors), Flexibility Factors (k-Factors), andTheir Determination for Metallic PipingComponents, for calculating the factors.
For most carbon steels, impact testing duringthe welding procedure qualification waschanged from being required for theweldment for design minimum temperaturesbelow -29oC (-20oF).
Impact testing for the weld metal fordesign minimum temperatures below-18oC (0oF), but impact testing of theweld metal is not required when theclassification of the weldingconsumables according to the filler metalspecification requires impact testing at orbelow the design minimum temperature.Impact testing of the weld metal and theHAZ of the procedure qualification testcoupon at or below the design minimumtemperature.
The new requirement is
Changed illustrated weld details from “typicaldetails” to “minimum weld dimensions” fordouble-welded slip-on flanges and socketwelding flanges.
FLANGE ATTACHMENT WELDS (PARA.328.5.2)
Added permission to use the rules of ASMEB31P, Standard Heat Treatments forFabrication Processes, as an alternate to therules is the Code for preheating and heattreatment.
HEAT TREATMENT (PARA. 330.1, 331.1)
The basis for allowable stresses waschanged from 0.67 times yield strength to asmuch as 0.80 times yield strength. Theallowable stress basis is now the same asASME BPV Code, Section VIII, Division 3. Themargin against burst at design pressure is1.732, and the lowest margin against throughthickness yielding during leak testing is 1.15.
HIGH PRESSURE FLUID SERVICEPRESSURE DESIGN (PARA. K302.3.2)
For fatigue analysis in previous editions, theCode permitted either a stress versusnumber of cycles (S/N) curve approach or afracture mechanics approach. The Code nowpermits the S/N curve approach only if it canbe shown that the piping component will failin a leak-before-burst mode. Otherwise, themore rigorous fracture mechanics approachis required.
HIGH PRESSURE FLUID SERVICE FATIGUEANALYSIS (PARAS. K302.3, K304.8)
