PWHT for skirt(non-pressure part)

[mohsenmaleki]

Dear all

tanks in advance for your attention,
scop of work for ASME code is pressure part,but is there any thing about PWHT for skirt about other than attached course to head.
PWHT is mandatory for skirt?
it would be appreciated to help us.

Regards,
M.Maleki

[Ali366]

Dear all

tanks in advance for your attention,
scop of work for ASME code is pressure part,but is there any thing about PWHT for skirt about other than attached course to head.
PWHT is mandatory for skirt?
it would be appreciated to help us.

Regards,
M.Maleki

Mohsen,

The weld which joins a non-pressure part to a pressure part is included in the scope of ASME VIII Div.1.

Therefore, skirt-to-head weld must be post weld heat treated if required by UCS56 and UW40 -- see UW-40(f)(5)(f)

Except for the skirt-to-head weld, ASME VIII does not require the rest of the welded joints in the skirt to be heat treated. Since other welds are not covered by ASME VIII, this is the design engineer's responsibility to specify whether other joints require PWHT or not. Also, have a look at your client's specification to see if they have additional requirements for PWHT. Such additional requirements would be mandatory as per your contract.

Cheers,

[GOLF1963]

Per the code the attachment weld required to be heat treated. No welding is allowed on heat treated items of the code vessel. The purpose of the heat treatment is to remove the weld stress from the vessel or for process reasons, the skirt is part of the vessel.

Most if not all customer spec's required the complete vessel to be heat treated. Most shirts have nozzles going through them and this can be a problem when it comes to installing the skirt.

You are saving very little money by not heat treating the skirt, and could cause you very large issues with your customer.


I have been designing vessels for 20 plus years and always heat treated the skirt, saddles, and legs with the vessel.

Hope this helps.