Caustic service PWHT/Preheat

[pipefabs]

Hi

I am handling a piping fabrication project. PWHT requirement as in client specification says "Follow the code (B31.3)" I have put the guidlines for my personnel as follows

Carbon steel : >3/4" wall thickness piping will have PWHT (and weld throat above this thickness for branch welds)
SS : None
(project has only cs and ss piping)

I am concerned about some lines with caustic service. Do we need any special care in caustic service as regarded to PWHT or preheat? is there any interpretation or reference in code?


Thanks in advance

 

[stanweld]

The Owner/Engineer should provide mandates for hardness & PWHT based on strength of the caustic and operating temperature. I would advise that you query the Owner/Engineer in this regard.