ASME B31.3-2016 PWHT Exemption

[JARivera1]

Table 331.1.3 Exemptions to Mandatory PWHT; simple question: fourth column header referrers Notes (3)-(5); it is mean that notes 3, 4 and 5 apply? to me yes, but may be a gap for somebody that 3 and 5 only; normally when is not well applied; if the designer has specified PWHT in the piping specification; this can not be waived specially in LTCS; any advice is welcome

 

[GD2]

You are right. Notes 3, 4 and 5, all apply.
Note 4 states that if the PWHT is specified by a Designer or WPS, exemption to PHWT is not allowed.

 

[r6155]

The code is for minimum conditions. Note (4) is obvious and should be deleted.

 

[JARivera1]

You are right. Notes 3, 4 and 5, all apply.
Note 4 states that if the PWHT is specified by a Designer or WPS, exemption to PHWT is not allowed.

Thanks GD2 for your feedback, I will post the follow up, I am doing to a field case

 

[JARivera1]

The code is for minimum conditions. Note (4) is obvious and should be deleted.

Thanks for your feedback r6155.
Believe or not there are CWIs that skipped the obvious requirement

 

[Sean_Wei]

By the way，is my understand right for the PWHT exemptions for P-No. 1 material in table 331.1.3
a）thickness＞25mm：preheat of 25℃ + multiple layer welds
b）thickness 5～25mm：multiple layer welds
c）thickness ≤5mm：not mentioned in the standard

 

[JARivera1]

The code is for minimum conditions. Note (4) is obvious and should be deleted.

Thanks for your feedback r6155.
Believe or not there are CWIs that skipped the obvious requirement