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How Find & Inspect LP & Natural Gas Appliance Shutoff Valves
- a Photo Guide
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This article describes the common locations of and inspection of LP or Natural Gas shutoff valves at heating appliances, stoves, and clothes dryers. A gas shutoff is a manual valve that can be closed to stop the supply of natural gas or LP gas to a heating appliance or to a building. We distinguish between a gas shutoff valve and a gas regulator, which may also be called a gas valve but which has the job of controlling gas flow into a heating appliance automatically in response to a call for heat. Gas regulators are discussed at Gas Appliance Regulator Defects.
Our page top photo shows a gas shutoff located at an outdoor gas meter - the valve is on the leftmost of the two vertical gas pipes at the top of (this improperly installed) gas meter.
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.
Green links show where you are. © Copyright 2013 InspectAPedia.com, All Rights Reserved. Author Daniel Friedman.
How & Where Locate & Inspect Natural Gas or LP Gas Fuel Shutoff Valves
Main Building gas shutoff valve located at the gas meter
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A main building gas shutoff valve are normally located at the main gas meter. An additional shutoff valve may be located in the street or sidewalk outside of the building - a device that cannot be readily seen nor used by a building owner.
We can see that the gas valve is in the "open" position because the movable lever is in the "down" position and parallel to the gas pipe.
Most gas companies advise their customers not to touch this valve. They worry that you'll damage the valve and cause a more serious gas leak than ever.
Call your local gas company for assistance with the valve or the meter. Usually, because serious safety concerns apply, the gas company will respond immediately. |
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Our photo (left) shows the shutoff valve on an outdoor LP gas tank. The direction to turn the valve to "close" it is marked by an arrow on the valve.
You should find an document the location of the main shutoff gas valve (usually located at the gas meter or if the meter is outdoors, a main valve may be installed inside the building close to where the gas pipe enters the structure.
The LP gas tank shutoff control (photo at left) is the gray knob at the right side of the picture.
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Gas shutoff valves at individual gas-fired appliances
Next you should find and document the location of individual gas shutoff valves at each appliance in the building that uses gas. Building codes require that a gas shutoff be located at each appliance and outside of the jacket or cover of the appliance.
Our photos show a natural gas shutoff valve installed at a gas-fired water heater (above left) and a gas shutoff valve installed at a gas-fired warm air furnace (above right).
Typical gas fired appliances that would each have its own gas shutoff valve include gas fired boilers or furnaces, clothes dryers, water heaters, and gas fired cook stoves or range tops.
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 In some cases such as where a damaged or corroded flexible gas connector line joins the appliance to the building gas piping, moving the appliance could start a dangerous gas leak.
In these cases, such as a range top, gas stove or clothes dryer which may be pushed against a building wall, we like to see an additional gas shutoff valve for such appliances located in a more accessible location. This permits the user or repair technician to turn off the gas supply without moving the appliance.
Our photo (left) shows a shutoff valve in an LP gas line that supplies a gas fired range top in a building where there was no other readily accessible location to provide a shutoff valve close to the appliance.
The range top was installed over an oven. An additional shutoff valve was installed inside the building but could not be readily accessed without lifting the range top or removing the oven below.
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Visual Signs of LP Gas Leakage at an Appliance Gas Valve
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 Even if the natural gas or LP Gas is shut off or no longer supplying an appliance, stains at the gas piping such as we show below this little LP gas shutoff at a water heater (in a city in Mexico) may indicate a history of leaks at the gas pipe connections.
In this case we found that a damaged, grooved mating face on a flare fitting had caused many years of slow gas leakage at this valve. The black stains at the flare fitting and copper tubing at the left side of the valve (photo at left) were pointed-to by the gas delivery driver as evidence of a history of gas leaks.
The repair required replacement of a flare fitting and re-making the joint.
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Gas shutoff valves located inside of heating appliance covers and jackets
Safety Recommendation: a gas shutoff valve should be installed in the gas line close to each gas-fired appliance/device. If your building has gas fired appliances that lack an accessible gas shutoff valve you should ask a licensed professional plumber or heating technician to install one.
Safety Recommendation: If you see that the local manual gas line shutoff valve at a gas-fired appliance has been installed only inside the jacket or cover, this is an unsafe condition: the valve could be
difficult to reach in an emergency.
Check with your local building code inspectors.
Relocation of such valves is usually a minor expense and can be handled by most licensed plumbers or heating service technicians.
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Abandoned gas shutoff valves may be very dangerous
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Gas valves may be left in place when an appliance has been removed.
If the gas valve does not include a lock to prevent it from being opened, the gas pipe should be capped so that the valve cannot be opened to let explosive gas into the building.
Our photo (left) shows a "live" natural gas line in an old house in Newburgh, New York.
Someone who doesn't know better might open this valve, causing a serious or potentially fatal explosion in the building.
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Gas surprises: Gas light and gas fireplace lines and valves may be "live" in older homes which used natural gas to supply energy to gas fireplaces or even to gas lights.
Never assume that an old gaslight fixture (photo at left) is safe and that the piping does not contain gas.
Often these fixtures were converted to electricity, having wires run conveniently through existing gas piping.
But an old gas fixture that has not been electrified may still release dangerously explosive gas into a building.
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Technical Reviewers & References
Related Topics, found near the top of this page suggest articles closely related to this one.
- National Fuel Gas Code, ANSI Z223.1-yyyy - American Gas Association / National Fire Protection Association
- LP-Gas Serviceman's Handbook,Fisher-Rosemount, Fisher Controls
- National Fire Protection Association (NFPA) Pamphlets No. 54 and 58.
- Specifications for Gas Installations, Central Hudson Gas and Electric Corporation
- "Gaslight", Gary Quilliam, The Old House Journal, March/April 1989 article describes fixtures, modern fixtures, and sources of supply.
- Residential Gas Hot Water Heater Pocket Partner - Testing and Trouble Shooting, 19. State Corp., Ashland City, TN 37015
- Also See: - HW Boilers: Leaks, Corrosion, Expansion Tanks, Air Purge
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
- Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the InspectAPedia Bookstore. Also see our Book Reviews - InspectAPedia.
er- Plumbing Diagnosis & Repair: Water supply, drainage, septic systems, water testing, water contamination, defective plumbing materials & products.
 The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 25th Ed., 2012, is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. Field inspection worksheets are included at the back of the volume. Special Offer: For a 10% discount on any number of copies of the Home Reference Book purchased as a single order. Enter INSPECTAHRB in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.
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