PWHT Requirement

[jonjose123]

We are currently doin a project in which 24" x 18 " pig traps are used. the thickness of major barrel is 12.7 mm and of that of the minor barrrel is 10.9 mm.
and it is designed as per ASME B31.4. DOes the requirement of PWHT applicable.

AS per ASME B31.4, PWHT is applicable only when the wall thickness is more than 32 mm.

Request to Please clarify.

 

[Duwe6]

Not required by Code; however, PWHT may be required by the customer. One reason would be Sour Service.

 

[jonjose123]

Hi Duwe6,
Thanks for the clarification.

The end closure is designed as per ASME Sec VIII Div 1, in that case , will PWHT required?

 

[weldstan]

Per ASME VIII, PWHT is not required for carbon steel (P No.1) less than or equal to 1 1/4 inch thick or up to 1.5" thick when 200F preheat is applied.
Service conditions (lethal or SCC) will dictate otherwise.