PWHT PWHT blaqesmith (Materials) (OP) 24 Mar 15 17:00 Dear Experts, Please guide me about following issue Q # 1 What is minimum thickness for PWHT for storage tank shell, Bottom(Construction code:API 650)? Q # 2 Where is it written in API 650? please share reference with me? RE: PWHT valleytank (Petroleum) 24 Mar 15 21:32 650 5.7.4 RE: PWHT valleytank (Petroleum) 24 Mar 15 21:35 Sorry for the double post. If you are asking about shell plate specifically I don't believe the code addresses that. RE: PWHT PogingLamig1 (Mechanical) 25 Mar 15 02:07 In additional be aware in the materials that quenched and tempered and read ASTM A537-Class 2. Hope it helps you.