Re: mill tolerance for pipes by ASME B 31.8/ B31.4

ASME B31.4 states:

402.4.5 Wall Thickness and Defect Tolerances

Wall thickness tolerances and defect tolerances for pipe shall be as specified in applicable pipe specifications or dimensional standards included by this Code by reference in Appendix A.

ASME B31.8 States:-

804.222 Nominal Wall Thickness

Nominal wall thickness,t, is the wall thickness computed by or used in the design equation in para. 841.11 or A842.221 in Chapter VIII. Under this Code, pipe may be ordered to this computed wall thickness without adding allowance to compensate for the underthickness tolerance permitted in approved specifications.

• In PipingDesign@yahoogroups.com, dd jdh <saduemk@...> wrote:
  >
  > Hi every one,
  >
  > The ASME Code B 31.3 has mentioned specifically on the addition of
  mill tolerance of 12.5% in its pipe wall thickness.
  > But is this mill tolerance mandatory for wall thickness of process
  pipes following B31.4 and B31.8 Codes.
  >
  > Thanks&Regards
  >
  > sadanand
  > middle east
  >
  >
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