PROPANE FACTS

It is fairly well known that propane is:

• Heavier - than air in its vapor form
• Is lighter than water in liquid form
• Weighs 4.2 pounds per gallon
• Vaporizes (boils) at 42 degrees below zero
• Has an odorant (ethyl mercaptan) added so we can smell it
• Has a vapor pressure directly proportional to its temperature
• Is nasty stuff (cold) so we wear gloves when handling it

Range of Flammability

• The range of percent of gas, in an air-gas mixture at atmospheric pressure that will support combustion.  For propane: 2.15% to 9.60%

Properties of Propane

• One gallon of liquid propane will produce 272 gallons of propane gas.
• For perfect combustion propane vapor in an air gas mixture should be 4%
• Air needed for combustion of one gallon of liquid propane is 6,528 gallons of air
• Total air-gas mixture is 6,528 gallons of air + 272 gallons of gas = 6,800 times the original propane volume
• A pint of liquid propane yields 272 pints of vapor or 4.5 cubic feet of propane vapor. This pint will yield 1,134 cubic feet of combustible mixture - a box measuring 5'x5'x5'.
• There are 120 pints in a 15-gallon stainless steel fuel tank
• An average basket contains about 45 cubic feet. At 4% propane gas, less than a cup is required for a combustible mixture in a basket
• An enclosed trailer (4'x8'x5') contained roughly 160 cubic feet. At 4% propane gas, less than 3 cups is required for a combustible mixture
• An average one-car garage contains about 1,964 cubic feet.  At 4% propane gas, about 2 gallons is required for a combustible mixture

Abnormal Propane Sources

• Overheated tank relieving pressure - in a garage or trailer
• Bleeding raw propane after landing
• Small spurt during refueling
• Leaking fuel fitting