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Here we discuss the procedure for converting from LP gas or "bottled gas" to natural gas or "piped in gas" at a building. General safety warning: improper installation and even improper inspection and testing methods involving natural or "LP" gas can involve dangerous conditions and risk fire or explosion. If you smell gas you should leave the building immediately and should do so without doing anything that could create a spark such as operating a light switch or telephone.

Advice for Converting From Propane to Natural Gas or from Natural Gas to Propane

If you are not sure whether your building and its appliances are served by LP gas (bottled gas or liquid petroleum gas) or by natural gas (piped-in gas), see the descriptions of each of these types of heating fuel at GAS PIPING, VALVES, CONTROLS.

Natural gas and LP gas appliance compatibility

These two fuels are similar in that both are used to provide energy to home heating systems and other appliances but they have some different properties of weight, method of distribution, and chemistry. Most gas appliances are delivered already set up to use either natural gas or LP gas but not both.

Most gas appliances can be converted from one fuel to the other - what is involved may be simply changing gas metering orifices in the equipment (for example at the burners on a stove) or it may also be necessary to change or adjust a gas regulator located inside the appliance. Do not hook up an LP gas-ready appliance to a natural gas supply nor can you connect a natural-gas ready appliance to an LP gas supply without reviewing and acting on the manufacturer's instructions for converting the appliance from one fuel to the other.

Important Safety Warning: be sure that all gas-fired appliances in your building have been properly set up for the correct type of gas to be consumed.

Do not connect an appliance set up for propane to a natural gas supply, and do not connect an appliance set up for burning natural gas to a propane gas supply without first making the required gas pressure and/or gas metering orifice adjustments. Making either of this mistakes can lead to gas leaks, fire, explosion, or potentially fatal carbon monoxide poisoning.

Virtually every modern gas fired appliance installation manual contains instructions for setting up the appliance to burn the proper fuel: LP gas (liquid propane from a tank installed at the property) or natural gas (piped in gas provided from a local gas utility company).

The pressure provided by natural gas is different from propane - adjustments will be needed at every gas fired appliance in the home.

Usually this means either an adjustment made at each gas burner at a metering device or in some cases a part actually has to be changed (an orifice through which the gas passes). On some appliances there may be a local gas regulator that also needs to be adjusted.

Where a gas burner metering device needs to be set properly for Natural Gas pressure or for LP gas pressure, the adjustment may be as simple as using a screwdriver or tool to turn the orifice from one position to another at each burner, or a part may need to be actually swapped out or exchanged. Appliance installation instructions will include sketches of where these parts are found as well as directions for how to set the metering device or regulator for the proper fuel.

Where is natural gas or LP gas pressure regulated for a gas fired appliance:

For LP Gas: at an LP gas pressure regulator mounted on or at the LP gas tank, possibly at an intermediate or buliding gas pressure regulator if the LP tank is distant from the building, at an LP gas pressure regulator inside of or at the gas fired appliance itself, and for some appliances such as gas ranges and ovens, additional gas flow regulation is performed by a special orifice right at the gas burner.

On many gas fired appliances the only adjustment that is required is to change or turn/adjust the gas metering orifice at the appliance burner.

Critical safety warnings about changing between gas fuel types: LP to or from Natural Gas

The proper setup of gas burning appliances is very important since failure to set the appliance for the proper gas type can result in very dangerous, even fatal carbon monoxide production from improper combustion.

If your natural gas supplying company or plumber who is doing the hookup has not already offered to do so, ask them to go through the home identifying every gas-burning appliance, determine exactly what changes are needed, and make them before the appliances are again turned on with the new fuel supply.

Follow the appliance setup and gas fuel type adjustment instructions in the appliance installation manual provided by the manufacturer. If you cannot find the installation manual for your gas fired water heater, stove, furnace, boiler, or other gas fired appliance, make a note of the appliance name, model number, and serial number, and contact the manufacturer directly for these critical instructions.

The actual conversion from LP to or from Natural gas at the appliance itself is usually quite easy, but doing it properly is essential for safety.

Also see Gas Regulators for Appliances and Gas Regulators for LP Tanks.

What to Do if You Smell Gas

*** Immediate LP Gas or Natural Gas Safety Concerns:

• Gas Odors: A gas leak can be indicated by gas odor such as in the utility area near appliances or elsewhere in the building.

From a safe location, call your gas company's emergency line and/or your fire department. The text provided here is a working draft and may be incomplete or inaccurate. Contact us to suggest text changes and additions and, if you wish, to receive online listing and credit for that contribution. Also see How to Report Defects in Oil Piping. NOTICE: while example report language is provided here, reproduction of this or any of our web pages or their contents at other websites or in printed documents for sale is prohibited.

You should have your plumber test, repair, or replace any suspect gas controls or piping promptly. Replacement of a control itself should not involve significant expense. This repair should not be deferred. You should be sure that building occupants know if this or other unsafe conditions are present.

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GAS PIPING, VALVES, CONTROLS
  Gas BTUH & Cubic Feet
  Gas Conversion LP Natural Gas
  Gas Flame & Noise Defects
  Gas Leak Detection
  Gas Lighting Pipes & Fixtures
  Gas Meters
  Gas Piping Defects
  Gas Regulators for Appliances
  Gas Regulators for LP Tanks
  Gas Shutoff Valves
  LP Gas Tanks
  LP & Natural Gas Safety Hazards
  Natural Gas Combustion Products
  Types of Fuel Gas Source

• U.S. Energy Information Administration - eia.doe.gov/
• U.S. Environmental Protection Agency - epa.gov/solar/energy-and-you/affect/natural-gas.html
• At Natural Gas.Org www.naturalgas.org/environment/naturalgas.asp#emission you’ll find a table of combustion products
• At geocities.com/rainforest/6847/report1.html is an interesting and detailed though not “neutral” report on the components and contaminants in the combustion of natural gas. You’ll see a long long list of emissions products, but look again – most of the contaminant levels listed are in the picograms.
• apvgn.pt/documentacao/iangv_rep_part1.pdf lists the components in natural gas exhaust from vehicles
• The Need Project, Manassas, VA: need.org/needpdf/infobook_activities/SecInfo/NGasS.pdf
• Kroschwitz, Jacqueline I., and Mary Howe-Grant (eds.). "Gas, Natural." In Encyclopedia of Chemical Technology. 4th ed., vol. 12. New York: John Wiley and Sons, Inc., 1993.
• Tussing, Arlon R., & Bob Tippee. The Natural Gas Industry: Evolution, Structure, and Economics. 2nd ed. Tulsa, OK: PennWell Publishing, 1995.
• Thanks to reader E Leal for suggesting the addition of details about how to convert gas burning appliances from propane to natural gas or from natural gas to propane. 8/4/09

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