SA 537 CLASS-1 PWHT Requirements

[GOPIn]

dear Sir, what is the minimum thickness required to do pwht for sa 537 cl-1 material

 

[Geoff13]

What Code are you asking about?

Since this is the storage tank forum it should be API 650, API 620 or similar. If this is a pressure vessel question it should be posted in another forum.

 

[IFRs]

For an API 650 tank, your shell material is in Group VI.
Per API 650 section 5.7.4 thermal stress relief (PWHT) is required for all flush-type fittings for any shell thickenss and PWHT is required for your tank for all openings over 2" NPS when the tank shell is more than 13mm [1/2"] thick.