The 190" I.D vessel has the nozzle (NPS 2") at head. It requires a PWHT at the welding junction (local PWHT around the nozzle). Mainly because of the room limit (no space to place the heating element..i.e) , we can not do the PWHT at outside of the vessel. My question is: there is any Codes/practice recommendations that allow/guide for a PWHT at inside of the vessel instead of outside? Note that the inside of vessel is clear and easy to access via the manhole. Thank you