Allgas Inc.

Propane Gas Properties

Propane gas is clean, safe and economical

BTU per gallon91, 547
BTU per Cubic Foot2,516
BTU per Pound21, 591
Pounds per Gallon4.24
Cubic Feet per Gallon36.39
Specific Gravity of Vapor1.52
Specific Gravity of Liquid 0.509
Boiling Point in Degrees Fahrenheit-44
Vapor Pressure in PSIG at 0 degrees Fahrenheit23.5
Vapor Pressure in PSIG at 100 degrees Fahrenheit172

Propane Chemical formula C3-H8

(3 parts carbon - 8 parts hydrogen)

Octane number125
Motor Fuel R/M104
Cu. Ft. Air Required to Burn 1 Cu. Ft. Gas23.5
Ignition Temperature920°F to 1020°F
Maximum Flame Temperature3600°F
Flashpoint L.E.L. (Lower Explosive Limit)2.4%
Flammability U.E.L.(Upper Explosive Limit)9.5%

Propane Gas is "Portable Energy"

Clean - Safe - Economical

The propane industry has developed numerous methods to make the transport and use of propane safe:

  • Propane equipment and appliances are manufactured to rigorous safety standards.
  • Propane has a narrow range of flammability when compared with other petroleum products. In order to ignite, the propane/air mix must contain from 2.2 to 9.6 percent propane vapor. If the mixture contains less than 2.2 percent gas, it is too lean to burn. If it contains more than 9.6 percent, it is too rich to burn.
  • Propane won't ignite when combined with air unless the source of ignition reaches at least 940 degrees Fahrenheit. In contrast, gasoline will ignite when the source of ignition reaches only 430 to 500 degrees Fahrenheit.
  • If liquid propane leaks, it doesn't puddle but instead vaporizes and dissipates into the air.
  • Because it is released from a pressured container as a vapor, propane can't be ingested like gasoline or alcohol fuels.
  • Because propane is virtually odorless and colorless in its natural state, a commercial odorant is added so propane can be detected if it leaks from its container.
See Safety Tips