Propane Relief Valve
Pressure set point can be from 250# to 375# depending on whether it is for a ASME Tank or DOT Cylinder
Relief Valve PSI setting S/B stamped on valve
I've seen 250 PSI settings and 312# settings
At 130*F the Propane Vapor Pressure would be 257 PSIG
At 110*F the Propane Vapor Pressure would be 197 PSIG
Store/transport cylinders UPRIGHT (milk crates work great)
IF laid on their sides the Relief Valve tube can be submerged in liquid and if it pops open would spew liquid propane which is very cool (instant frostbite) and then would turn to a very large vapor cloud (expands 270 times it's volume)
Propane is HEAVIER then air and will sink/pool in low areas.
