PWHT Temperature Ranges

[humbug]

B31.1 requires a pwht temp. of 1200-1300F for P4 material while B31.3 requires a pwht temp. of 1300-1375F for the same.
We have a WPS qualified w/ pwht and its utilizes the 1300-1350F temp.
Can we back this up somewhere in B31.1 to use this procedure? I was thinking since we are under the Lower Critical Temperature (~1430F) we would be okay, since it is 80F below

Thanks,

 

[metengr]

humbug;
Yes, you can use the higher PWHT temperature range in the WPS even if it exceeds the upper PWHT limit because it is only a recommended value. Please carefully review the excerpt below, it is in ASME B31.1 2008

132.2 Mandatory PWHT Requirements
Heat treatment may be accomplished by a suitable
heating method which will provide the desired heating
and cooling rates, the required metal temperature, temperature
uniformity, and temperature control.
(A) The upper limit of the PWHT temperature range
in Table 132 is a recommended value which may be
exceeded provided the actual temperature does not
exceed the lower critical temperature of either material
(see Table 129.3.2).

 

[humbug]

metengr,

Thanks, I really appreciate the info.
I just breezed right over the paragraph.

Humbug