Hello,

I'm working on a pump project in which my Minimum Design Metal Temperature (MDMT) temperature case of -20 deg F is actually governing in terms of the highest loadings on the pump nozzles. Design temperature is only 110 deg F, so this seems realistic to me if you look at the B31.3 thermal displacements table. The flow media is crude oil and is meant to be running continuously at 60 deg F operating (so MDMT occurrence should theoretically be very rare)

Question #1:
Do MDMT conditions really fall under the intent of the API 610 nozzle allowables? It seems to me that these allowables are meant to avoid a badly designed pipe route causing shaft deflection/vibration during an OPERATING scenario (hence, I've originally assumed these as operating allowables). It seems that if the pumps are shut off, then i could see some deflection/stresses induced on the casing and nozzles. Any opinions here?

Question #2:
I've seen a few posts regarding whether or not Occasional loadings should be included for checking these allowables. My initial approach is to combine the Occasional loadings with my design temperature case. However, I'm stuck with 1x the Table 5 allowables so I am now considering combining my Occasional loads with operating temperature case instead (60 deg F). Does anyone see any issues with this approach?