PWHT/Stress- Relieving

"If the wall thickness of 12" ASTM A106 Gr.B"???????????????????????????

Don't mix units.

What do you mean by your answer?

CORAL,
Excellent reply. The fellow who replied to your original post does not know anything about ASME, EN, JIS, piping, pressure vessel, boilers, offshore jackets,pipe lines, storage tanks etc. Moreover, never give reply to these ignorant people.These guys think as if they know everything under the sun.ROFL
Have a nice day.

Let's see your knowledge of any of this.

If you need to comply with both codes, you must conform to the more stringent provision in each case. If complying with only one, simply follow it without referencing the other.

First of all, I never come across any kind of Canadian Codes, Standards etc.

If you are strong in materials science, code doesn't matter for material thickness selection for PWHT. Stress relieving generally applied to ferritic steels to relieve the residual tensile stresses generated during welding from weld metal as well as heat affected zone. However, sometimes Austenitic stainless steels and duplex stainless steels are solution annealed to meet the fluid service requirement.

Following things I have observed from your query,

1. ASTM materials are acceptable materials as per CSA coded construction.

"Our project is designed by CSA Z662 and pipe materials are using CSA and ASTM together"

Generally PWHT requirements are based on construction code. However, pls check your welding specification for clarification. PWHT on CS welded joints above 20mm is always good for longer piping life during service. PWHT will reduce the chances of stress corrosion cracking of welds and HAZ in long run. But your piping fluid service is not much aggressive or lethal and the service condition not in severe cyclic condition, then you can avoid stress relieving for lower thickness.

Hope this helps.

"My" query?