Typical Properties of Propane

Formula C3H8

Range of inflammability (air) 2.15% to 9.60% Perfect combustion (air) 4.34% Ignition temperature 940F

Vapor pressure, psig at 60F 92
Vapor pressure, psig at 100F 172

BTU/gal 91,500
BTU/cu. ft. of gas @ 60F, 2,520
BTU/lb. of gas 21,560

Lbs. per gal 4.23
Specific gravity 0.51

Boiling point of liquid at atmospheric pressure -44F

Cu. ft. of gas per pound of liquid 8.59
Cu. ft. of gas per gallon of liquid 36.5
Specific gravity of gas (air = 1) 1.53

Note properties are at 60F.