PROPANE
BY FRANK L. FIRE
Propane is a flammable, colorless, odorless, tasteless, nontoxic hydrocarbon gas. It burns relatively cleanly and is an excellent fuel. Although propane is a flammable gas, it is usually shipped and stored as a liquid. An odorant is added so it can be detected if it leaks from its container. It has an ignition temperature of 8427F and explosive limits of 2.1 percent to 9.5 percent in air. The liquefied gas has a specific gravity of 0.531 and a molecular weight of 44. Its vapor density is 1.517. It boils at 2447F, freezes at 2309.87F, and is not soluble in water. Although gases have no flash points (since they are already in the “right” form to ignite), the liquid often has a flash point of 2248.87F listed in the literature. This “information” is totally unnecessary, since there is no region on earth that has this ambient temperature.
Propane`s CAS (Chemical Abstract Services) number is 74-98-6. Its UN/NA (United Nations/North America) designation is 1978 for the gas and 1075 for the liquefied state, known as LPG (liquefied petroleum gas). LPG may also be a mixture of propane, butane, and some isomers of butane. Propane`s STCC (Standard Transportation Commodity Code) number is 4905781, its RTECS (Registry of Toxic Effects of Chemical Substances) designation is TX2275000, and its NFPA (National Fire Protection Association) 704 hazard rating is 1-4-0. Propane`s molecular formula is C3H8.
Propane has a very wide range of commercial, industrial, and residential uses, estimated to be in the thousands. In some very few applications, it may be mixed with butane.
In residential uses, including motor and mobile homes, it is used as a fuel for heating and cooking and operating hot water heaters, refrigerators, and air-conditioners. It has much the same uses in commercial situations. It is also used as a fuel to power automobiles, light trucks, and buses. (Editor`s note: In the United States, most propane installations into dwellings are piped from the container and must meet specific safety requirements, including those of the Department of Transportation, according to Bruce Swiecicki, vice president of technical services for the National Propane Gas Association in Lisle, Illinois.)
In industrial operations, it is used as a heating fuel; as a fuel for forklifts and other industrial trucks; as a source of energy for fire boilers, kilns, or other furnaces; and to provide heat for various types of drying operations. It is used in industry where precise heating is required, as in annealing, brazing, enamel baking, metal cutting, and soldering. Industrial operations that use another fuel as the primary heating fuel may use propane as a backup. Electric utilities often use propane to supplement the burning of natural gas during peak demand periods. Propane has uses also as an aerosol propellant, a solvent, an extractant (in the liquefied state), an agent in the synthesis of many organic materials, a foaming agent for some foamed plastics, and a refrigerant.
It has many uses in agricultural operations as well, especially where natural gas lines have not been extended. It is used not only to heat and cook but also to dry farm products including tobacco. Propane is often used to power well pumps, small electric generators, and small engines used for a variety of purposes.
FRANK L. FIRE is the vice president of marketing for Americhem Inc. in Cuyahoga Falls, Ohio. He`s an instructor of hazardous-materials chemistry at the University of Akron as well as an adjunct instructor of haz mats at the National Fire Academy. Fire is the author of The Common Sense Approach to Hazardous Materials and an accompanying study guide, Combustibility of Plastics, and Chemical Data Notebook: A User`s Manual, published by Fire Engineering Books. He is an editorial advisory board member of Fire Engineering.
