For equipment, wherein design pressure plus static head is considered, PV Elite considers the increased design pressure in the nozzle reinforcement calculation. However, for the flange rating checks, only design pressure (without static head) is considered.

CodeCalc has a provision for "rating the attached flanges", which takes care of the above problem. However, PV Elite nozzle box doesn't have this feature.

Hence, in the event of a borderline case where the nozzle flange may be safe for the design pressure-temperature combination but not for the pressure with static head added, the output still shows no "failure" or "warning".

Please advise.

Hi San,

Actually PV Elite does include the effect of static head on the flange rating. To check this put a nozzle with flange in a bottom head with some liquid above it. Make the shells thick enought such that they don't control the MAWP. Run the model and review the Internal Pressure report. you will notice a few lines like this:

Note : The M.A.W.P is Governed by an ANSI Flange !

Flange MAWP including Static Pressure: 257.544 = 260.000 - 2.456 psig

Note : The M.A.P.(NC) is Governed by a Flange !

The following warning also appears in the Vessel Summary report.

** Warning: An ANSI Flange is limiting the MAWP and this may affect the
pressure used in the Nozzle Reinforcement Calculations.