Ashishpvnit A:For 12 NPS > sch 80 rating PWHT of nozzle will be required B: Irrespective of shell thickness- PWHT requirement depends on type of service / storage use. C. Yes PWHT for openings of 12 NPS or larger sizes for shell thickness 25 mm D.1. Question needs clarificaiton D.2. Answer as above will be applicable for clean out doors. nozzles to shell of size 12 NPS or larger D. 3. Impact for shell plate for services below ambient temp is different from compact bar used at the roof top. Compact bar does not see low temp use at any time. Impact test to sub zero conditions will not apply Hope this helps C.V.Srinivasan Nishi Engineers Pvt Ltd India Sept 16, 2010 E-mail: nishi@vsnl.com Question is not clear >Dear Experts, > >I have some querries regarding PWHT or Stress Relief & >Impact Testing requirement:- >1 With respect to API code For Shell Material in Group >I,II,III or IIIA :- >A) Does it mean stress relieved is required for all openings >NPS 12 or larger in nominal diameter in shell plate >irrespective of shell thickness?---YES OR NO ? > >OR > >C) B) Is it required for all openings NPS 12 or larger in >nominal diameter in shell plate thickness more than 25 mm >thk---YES OR NO ?? > >OR > >D) Required for all openings NPS 12 or larger in nominal >diameter in thickened insert plate thickness more than 25 mm >thk---YES OR NO ?? > >What is meant by thickened plate ? Is it Different then >shell plate? > >2) Wether PWHT is required for all shell manways,cleanout >Doors as their sizes are always more than NPS12---YES OR NO >? > >3) API code is telling impact test requirement for shell >only if you refer mini. permissible design metal temp for >material used in tank shell without impact test,Fiure 4-1a & >Table 4-3a,API 650 11Th Edtn,Addend-II.What if thickness of >compression bar at roof reqd due to high participating is >very high.In that case will impact test be required?---YES >OR NO ? > > >Ashish Pande >Design Engg Tanks >Mtech-Thermal Engg >Nagpur-India:-) :-)