Zahra Revised hardness guideline under MR-0175 for sour service is RC 20 around 210-215 BHN. Sour service - concentration of H2S - may vary depending on the crude processed in your plant or purchased from oil producing sources. If yur hardness profile - which is not fully mandatory - as per NACE guideline or API for thickness of 3/4" (19 mm thickness), you may take a profile of random welds. HAZ/ parent metal (API 5 LB) or X 52 and ascertain that the hardness are lower than Rc 20 (< 200 BHN). If you suspect that crude processed and sour concentration in the crude oil may vary drasticaly on the higher side ( in future). try S.R. This will be safer bet from future SCC problem in the welds or parent metal. This is not a mandatory requirement as per API code or NACE MR 0175 guidelines or ASME B 31.3 code as of now. Trust this helps you C.V.Srinivasan Nishi Engineers Pvt Ltd India Oct 01, 2006 E-mail: nishi@vsnl.com >Hi > >I was wondering if there is any additional requirements for >PWHT of API 5L B & X52 in sour service. >material meet the NACE MR-01 75 >Should we decrease the wall thickness limit of ASME B 31.3 >for PWHT in sour service. less than 3/4" > >Otherwise ,is there any mandatory hardness test after PWHT >in sour service Max 22 HRC? > >Design code is ASME B31.3 > >Best Regards >Zahra