ASME PCC Pmax interpretation

[Ehiman1]

Hello everyone,
I noted that Compress used Pmax = Mawp in the ASME PCC-1 calculation for main flanges.
In ASME code Pmax = maximum design pressure and because of this reason the verification on Compress is too restrictive to me.
Does anyone noted this different software interpretation?

Thank you

 

[mk3223]

Should it be typical for designing the pressure vessel?

The Pmax in the ASME Code is mainly used for the main body design of the pressure vessel, which has the majority material as well as the cost of the equipment. Comparing to the vessel body, the nozzle flanges are relative small quantity which may be designed to be MAWP per ASME Code, which is complied with all the "maximum design pressure" up to MAWP but without adding additional cost.

 

[GD2]

Ehiman1,
ASME code vessel design starts with design pressure. Because the vessel wall thickness comes in discrete thickness which most of the time exceeds the design thickness, it ends up in a higher pressure rating translated into MAWP.

The vessel can safely operate upto the MAWP. Relief valves are set on MAWP. For those vessels whose MAWP is not calculated, MAWP = Design Pressure.

Hence, the consideration of MAWP in PCC-1 as opposed to design pressure in ASME Code.

This is also the reason why hydro test pressure is based on MAWP.

GDD
Canada