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Gas piping in buildings: defects, inspection, trougleshooting, leaks, repairs: in this article series on gas piping we provide descriptions and photographs of unsafe gas piping, indications of unsafe or improperly operating gas appliances, gas meters, and other gas installation defects are provided.

This article series on gas piping, lighting, fixtures, and related topics provides free sample draft home inspection report language for reporting defects in oil and gas piping at residential properties.

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. 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.

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How to Identify & Report LP Gas or Natural Gas Fuel Piping Defects

Safety Warnings for Gas Leaks

Immediate LP or natural gas safety hazards: if there is evidence of an LP or natural gas leak at a building, gas odors, for example, you should:

• Do not do anything that is likely to cause a gas explosion, such as lighting a match, operating an electrical switch, or even using a telephone in the building
• Leave the building immediately and keep a safe distance away - 100 feet or more.
• Notify other building occupants of the safety concern
• Contact the local gas company and/or fire department

Heating equipment which the inspector (or building occupant or manager) judges to be an immediate life safety hazard should be shut down and appropriate emergency services called. See Gas Leak Detection for leak detection procedures and alternatives.

LP Gas Regulator Installation Requirements

• Gas regulator ground clearance: LP gas regulators should be installed at least eighteen inches above the surface of the ground. In areas of deep snow the regulator should really be above the snow level (or protected from weather)
• Protect gas regulator from weather: the LP gas regulator(s) should not be located where they are exposed to large amounts of water (or ice) such as below a roof eave with no gutter, or close to a downspout opening.
• Gas regulator hoods: The LP Gas regulator installed outdoors should [in best practice] have a protective hood to avoid damage from rain or (in freezing climates) ice. If an LP gas regulator is being installed horizontally, that is without pointing it's vent opening down, it must be protected by a cover, and even under the cover the vent should slope down to avoid risk of accumulating condensate and frost blockage, an condition which would be unsafe as frost or ice can prevent safe operation of the gas pressure regulator.
• Point vents down: Where a regulator is installed outside without such protection, it is very important that the regulator is placed with its vent pointed straight down so that rain and ice do not enter and possibly block the vent - a dangerous condition
• Distance between LP gas regulator and building openings: LP gas regulators should be installed at least five feet from any building window or vent or air intake (ten feet if a buried LP tank is in use).

LP Gas Regulator Inspection Procedure

The LP Gas regulator(s) should be inspected each time that the building receives an LP gas delivery.

• Turn off the LP gas service valve at the tank and check for gas odors anywhere. If gas odors are present we suspect the main shutoff valve is defective and it may need replacement.
• Check that the LP gas regulator is properly installed, sloped so that its vent will drain, and that it is protected from the weather
• Check that the LP gas regulator vent has not become blocked. We sometimes find that insects will nest in openings on these devices, blocking the vent screen with mud or insect nest materials. Make sure the regulator vent has not become blocked with anything whatsoever.
• Check the LP gas regulator for evidence that water has leaked into it by looking into the regulator's cover-cap (a removable cap). A service technician may also shut down the gas system and remove the regulator's adjusting screw to check the regulator interior for corrosion. It is particularly important to look for evidenceof corrosion in the pressure relief valve area inside the regulatorr, since if this component is corroded the relief valve may not function safely.
• Gas service experts recommend replacing an LP gas regulator if it is more than fifteen years old.

LP Gas Piping Defect List & sample home inspection report language

Safety warnings about gas piping: Check condition of flexible gas line connections: Caution: home inspectors and other private building inspectors do not pull out appliances to look at gas line connections, but you should do so, or have your service technician do so, in order to check condition of flexible connections for leaks and assuring that a shutoff valve is installed. Watch for leaks in those flex-connector lines between gas line and the appliance as they are thin wall and often corrode and leak. Gas leaks are dangerous.

Safety warning. Flexible soft copper piping defect example: if flexible soft copper tubing has been used to supply municipal (natural) gas to a electric clothes dryer, hot water heater, or heating system, this is not a recommended installation and it may be prohibited by local codes - "black iron" steel piping is required in many jurisdictions.

Safety warning: Flexible ridged thin wall copper tubing defects: if flexible "corrugated" or flexible thin-wall copper tubing been used to supply gas to a hot water heater, or heating system, this is not a recommended installation and it may be prohibited by local codes.

Technical Violation: Flexible copper LP gas line may not be routed through walls or similar locations where it may be damaged or punctured. For these sections of routing threaded iron pipe is required. This is an usually inexpensive item to correct. You can discuss this point further with your gas supplier and your plumber.

All gas or oil piping must comply with local codes and ordinances or with the national fuel gas codes. Copper and brass tubing (except tin lined copper) shall not be used if the gas contains more than an average of .3 grains of hydrogen sulfide per 100 standard cubic feet of gas.

"Abandoned" live gas piping: Watch out: don't assume that all "old or antique gas pipes" in a building have been actually disconneted from the gas supply.

We have found "live" gas supplied in fireplaces in older homes where a gas log or heater had previously been installed and "live gas" supplied at antique gas lighting fixtures that occupants thought had been disconnected. An example of a surprising "live" gas light is shown in our home inspection photo (left) from a New York home constructed in the 1920's. See Gas Lighting Pipes & Fixtures

*** Safety: gas line loose: At [record location of observed piping defect] you will need to provide better for the gas piping. Loose piping risks dangerous gas leaks. Even if you did not observe/smell a leak at this location when we inspected. This item should be handled as soon as possible.

*** Safety: We recommend that unused gas equipment be removed and that you have the unused section of gas line properly sealed by a qualified plumber or by your gas supplier. Leaky old appliances or gas lines are dangerous.

Gas Piping Maintenance Tips

MAINTENANCE TIP: Openings where the gas supply pipe enters the building should be caulked to reduce possible water or insect/rodent pest entry.

Safety Recommendation: the gas supply line at
... is not installed according to the manufacturer's recommendations. Proper iron pipe plumbing with sediment trap, also called a "drip leg" (typically at least 3" long off of a "tee" at same height as the gas control) should be installed. This is an inexpensive plumbing correction and it should corrected soon to avoid moisture damage to the gas controls. (Note that depending on the quality of the gas being delivered in some municipalities, the installation of a drip leg or dirt leg may not be required by local officials.

*** Safety: gas line loose: At
...
better support is needed for the gas piping. Loose piping risks dangerous gas leaks.
... We did not observe/smell a leak at this location when we inspected. This item should be handled as soon as possible.

*** Safety:We recommend that unused gas equipment be removed and that you have the unused section of gas line properly sealed by a qualified plumber or by your gas supplier. Leaky old appliances or gas lines are dangerous.

Questions & Answers regarding this article

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GAS PIPING, VALVES, CONTROLS
  Gas BTUH & Cubic Feet
  Gas Conversion LP Natural Gas
  Gas Flame & Noise Defects
  Gas Igniter Defects, Repairs
  Gas Leak Detection
  Gas Lighting Pipes & Fixtures
  Gas Meters
  Gas Piping Defects
  Gas Regulators for Appliances
  Gas Regulators for LP Tanks
  Gas Regulators, Two Stage
  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.

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