What are the governing equations for compressible fluid flow? Specifically; methane gas inlet pressure of 25 psi through a 3/8" dia. pipe and I need to relate this to a methane flow of 392,000 BTU/ hr @ 55-60psi 59 F and RH 60% (i.e. ISO 2314) through an as yet undetermined diameter pipe, assume methane has 1,000 BTU/cu. ft. @ ISO 2314. I'm not sure if there's sufficient gas @ 25 psi through the 3/8" tube to meet the demand. Thanks for your insights!