ASME VIII Division 2 Pressure vessel openings without reinforcement

[Kieran22]

Hello,
I am designing a cylindrical pressure vessel which requires openings in the wall and head. In AD-510 of ASME VIII division 2 c., it is stated that "No unreinforced opening shall have it's center closer than 2.5*sqrt(R_m*t) to the edge of a locally stressed area in the shell, where R_m is the mean readius and t is the nominal thickness of the vessel shell or head at the location of opening".
Is R_m referring to the mean radius of the vessel or the mean radius of the openings?
Thanks in advance.

 

[TGS4]

STOP!!!

You are using an Edition of Division 2 that is now at least 5 years out of date. Please use the latest version, and then come back here with your question (which might actually be answered in the newest Edition/Addenda).