Propane gas sizing

[StephenJcan]

I have been told by the rep of a large propane supplier that propane pressure going into a building is usually less than 1lb. Well the tables provided in NFPA show sizing with either 10psi or less than 1lb. I just wanted to know how to go about sizing propane. If you have a 10 million BTU/h requirement for a warehouse what would be the pressure needed and the size of pipe needed?
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[sigmapsi]

from what i recall, the tables in nfpa 54 are based on natural gas. the natural gas capacities at various pressures and pipe sizes must be adjusted for specific gravity factors for propane. nfpa 54 has another table of correction factors for specific gravity. sorry i can't recall what the factor is for propane, but it can easily be calculated through ASHRAE handbooks or perhaps through NFPA resources.

 

[StephenJcan]

NFPA 58 governs propane. I have used the tables for natural gas and for propane but speaking with a propane gas rep there seems to be some other tables that are out there not in the NFPA. I have developed a spreadsheet that calculates any of the following variables: downstream or upstream pressure, length of run, gas load, diameter of pipe. However this does not help me with the propane gas sizing inside buildings. If I get more info from the rep I will post it here.

 

[prodeng]

The main objective of the pipe sizing is to make sure you have adequate pressure (which relates to flow rate) for the operation of the equipment. Once you know your mass flow needed, and required pressure at the equipment with the longest pipe run, everything else will have to be regulated. From what I have seen, much of the equipment contains a regulator on it, but it has a minimum pressure it will work at. Based on your comment on a spreadsheet, I take it you know how to calculate pressure drop through the pipe.