Propane Info

What Is Propane?

Propane, or liquefied petroleum (LP-gas), a fossil fuel, is one of the nation’s most versatile sources of energy and supplies 3 to 4% of our total energy. Propane is an approved, alternate clean fuel listed in the 1990 Clean Air Act as well as the National Energy Policy Act of 1992. Propane can be either a liquid or a gas. At normal atmospheric pressure and temperature, it is a non-toxic, colorless and odorless gas. Under moderate pressure, propane becomes a liquid that vaporizes into a clean-burning gas when released from its storage container. Just like natural gas, an identifying odor is added so it can be readily detected.

Sources of Propane

Propane comes from two sources: from the production of natural gas and from the production of crude oil. About 90 percent of the propane sold in the U.S. is domestically produced. The remainder is imported with most coming from Canada via pipeline and rail.

Crude Oil

30% of the propane used in the US comes from the production of crude oil. It is separated into its various parts at a processing plant called a refinery. LP-gases are processed from crude oil by heating the crude oil until it begins to boil. The boiling crude oil produces many different gaseous hydrocarbons, including propane and butane. These different gases are captured under pressure and slowly cooled. Each of the gases will condense into a liquid, one at a time, as the temperature drops below the boiling point of each gas. Both propane and butane are captured in this manner and stored as a liquid under pressure.

Natural gas

70% of the propane used in the US comes from the production of natural gas. LP-gases are extracted from the raw natural gas at a processing plant. When natural gas is removed from a gas pocket it is normally referred to as a “wet” gas. The term “wet” means that the gas is a mixture of hydrocarbon gases and, in some cases, liquids. Once removed from the ground, the different gases and liquids are separated, processed and refined. Among the gases and liquids removed are methane (chief component of “natural gas” used in appliances), propane, butane, and, in many cases, natural gasolines (pentane, heptane, etc.) The two primary sources of LP-gases are quite different. However, once refined, there is little difference between the LP-gases processed from crude oil and those processed from “wet” natural gas.

Distribution

Once the propane has been derived from its raw form, it is then distributed in many ways across the United States to a variety of locations.

  • 70,000 miles of cross-country pipeline
  • 25,000 transport and delivery trucks
  • 22,000 railcars
  • 8,000 bulk storage and distribution terminals
  • 320 barges and tankers
  • 250 primary storage facilities
  • 25,000 retail outlets supplying propane
  • 6.2 billion gallons of underground storage

Chemical Properties and Characteristics of Propane

  • Chemical Name:Propane
  • Chemical family: Paraffinic Hydrocarbon
  • Formula: C3H8
  • Synonyms: Dimethylmethane, LP-Gas, Liquefied Petroleum Gas (LPG), Propane, Propyl Hydride
  • Propane can be composed of the following ingredients:
  • Propane: 87.5 to 100%
  • Ethane: 0 to 5%
  • Propylene: 0 to 10%
  • Various Butanes: 0 to 2.5%
  • Ethyl Mercaptan*: 16 to 25 ppm*
  • Propane gas is colorless, tasteless and odorless. Ethyl Mercaptan is an odorizing agent added to propane so that leaks may be detected by smell.
  • Flash Point: -156° F (-104° C)
  • Auto Ignition: 842° F ( 432° C)
  • Ignition temperature in air: 920-1120° F
  • Flammable limits in air by volume: Lower = 2.15%, Upper = 9.6%
  • Maximum flame temperature in air: 3,595°
  • Boiling Point: (@ 14.7 psia) -44° F
  • Specific Gravity of Vapor (air = 1): 1.5 (at 60° F)
  • Specific Gravity of Liquid (water = 1): .504 (at 60° F)
  • Vapor Pressure: @ 70° F = 127 psig, @ 105° F = 210 psig
  • Expansion Ratio (from liquid to gas @ 14.7 psia): 1 to 270

One cubic foot of propane liquid will boil off into approximately 270
 cubic feet of vapor. As a result, a leak in any propane container,
large or small, can easily lead to a flammable mixture of propane and
air. The release of propane as a vapor or a liquid causes no adverse ecological effects.
It does not contain any Class I or Class II ozone-depleting chemicals
(40 CFR Part 82) and it is not listed as a marine pollutant by DOT
(49 CFR Part 171). Propane gas, however, displaces oxygen in the air.
If the ratio of propane to oxygen is high enough, it can cause
 asphyxiation.

  • BTU Per Gallon: 91,502
  • BTU Per Cubic Foot: 2,516
  • BTU Per Pound: 21,591
  • Pounds Per Gallon: 4.20
  • Cubic Feet Per Gallon: 36.38
  • Cubic Feet Per Pound: 8.66

Propane gas is stored and handled as a liquid when under pressure inside an LP-gas container. It vaporizes, changing from a liquid to a vapor when released to the atmosphere at a temperature above -44° F. When released into the atmosphere, the gas condenses moisture from the air and thus appears as a white cloud or fog at the point of discharge. The outer edge of this white fog is flammable and will flash if brought in contact with a source of ignition. LP-gas inside a container is in two states of matter, liquid and vapor. The liquid portion of a container is in the bottom area and the vapor is in the upper area above the liquid. Containers are normally filled to only 80% to allow for vapor expansion due to temperature increase. Vapor pressure of propane increases as the liquid temperature increases. Propane at -44° F inside a container would register zero pressure. At 32° F, the pressure would increase to 54 psig and at 100° F the pressure would be 205 psig.

Propane has an enviable safety record due to the stringent codes and regulations developed by the propane industry in conjunction with the National Fire Protection Association (NFPA). Every aspect of installation, storage, and tank filling has been considered to ensure worry-free operation. The strict safety codes mandated by the propane industry are further enhanced by propane’s naturally safe features. For starters, propane has a narrow range of flammability, meaning the propane/air mix must contain from 2.2% to 9.6% propane vapor to ignite. Any less than that and the mixture is too lean to burn; any more than that and the mixture is too rich to burn.

Also, propane will not ignite when combined with air unless the source of ignition reaches at least 940F. In contrast, gasoline will ignite when the source of ignition reaches 430F to 500F. In addition, because propane is released as a vapor from a pressured container, it cannot be ingested like gasoline or alcohol fuels. If liquid propane leaks, it vaporizes and dissipates into the air.

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.
  • The odds of a person dying from a direct result of a propane transportation or storage accident involving loss of cargo are about the same as those of getting struck by an airplane falling from the sky.
  • If liquid propane leaks, it vaporizes and dissipates into the air.
  • Propane is released from a pressured container as a vapor, and a commercial odorant is added so propane can be detected if it leaks.
  • 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.
  • The Certified Employee Training Program (CETP) is a nationally recognized training program for people involved in the handling of propane, as well as propane equipment and appliances. CETP is used extensively throughout the country and is continually expanded and updated.
  • Each year, thousands of industry employees and firefighters attend service and safety schools sponsored by the industry. The sessions provide important training in how to quickly control and safely handle a propane emergency.
  • Propane is an approved, alternative clean fuel listed in the 1990 Clean Air Act as well as the National Energy Policy Act of 1992.
  • Propane is one of the cleanest burning of all fossil fuels. Tests conducted by the U.S. Environmental Protection Agency show that propane-fueled vehicles produce 30 percent to 90 percent less carbon monoxide and about 50 percent fewer toxins and other smog-producing emissions than gasoline engines.
  • Burning coal to generate electricity releases carbon dioxide and other pollutants into the atmosphere. Per pound of fuel burned, coal emits more than twice the amount of carbon dioxide as does propane. By using propane gas instead of electricity, consumers can cut emissions and help preserve the environment.
  • Propane gas is nontoxic, so it’s not harmful to soil and water.
  • According to the EPA, much of the sulfur dioxide in the atmosphere, which produces acid rain, is attributable to coal-fired, electricity-generating facilities. In contrast, neither the process by which propane is produced nor the combustion of propane gas produces significant acid rain contaminants.
  • According to the U.S. Department of Energy, it could cost consumers twice as much to operate their range, water heater, dryer or furnace with electricity than with propane gas.
  • Overall propane costs for fleet vehicles typically range from 5 percent to 30 percent less than conventional or reformulated gasoline. Many states offer fuel tax incentives to encourage the use of clean fuels, thus further reducing operating costs.
  • Propane is used by millions of people in many different environments-homes, industry, farming and more.
  • More than 14 million families use propane to fuel their furnaces, water heaters, air conditioners, outdoor grills, fire places, dryers and range tops.
  • Nearly 500,000 forklift trucks are powered by clean-burning propane. Millions more choose propane to fuel for bus, taxi, and other fleets to minimize air pollution in metropolitan areas.
  • Propane is used on 660,000 farms for irrigation pumps, grain dryers, standby generators and other farm equipment. It is an essential fuel for crop drying, flame cultivation, fruit ripening, space and water heating and food refrigeration.
  • Propane is easy to transport and can be used in areas beyond the natural gas mains. Because it is 270 times more compact as a liquid than as a gas, it is economical to store and transport as a liquid.
  • 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.
  • The odds of a person dying from a direct result of a propane transportation or storage accident involving loss of cargo are about the same as those of getting struck by an airplane falling from the sky.
  • If liquid propane leaks, it 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.
  • The Certified Employee Training Program (CETP) is a nationally recognized training program.
  • Each year, thousands of industry employees and firefighters attend service and safety schools sponsored by the industry. The sessions provide important training in how to quickly control and safely handle a propane emergency.
  • Propane is an approved, alternative clean fuel listed in the 1990 Clean Air Act as well as the National Energy Policy Act of 1992.
  • Propane is one of the lightest, simplest hydrocarbons in existence, and, as a result, is one of the cleanest burning of all alternative fuels. New propane-fueled vehicles can meet the very tough Ultra-Low Emission Vehicle (ULEV) standards, and one model even meets the Super Ultra-Low Emission Vehicle (SULEV) standards.
  • Propane gas is nontoxic, so it’s not harmful to soil and water. Because propane does not endanger the environment, the placement of propane tanks either above or below ground is not regulated by the Environmental Protection Agency (EPA).
  • Because propane produces minimal emissions, it is safe to use indoors. As a result, nearly 500,000 forklift trucks are powered by propane. Millions more choose this clean-burning alternative for bus, taxi, delivery and other fleets to minimize air pollution in metropolitan areas.