Gas appliance, heater, piping & control safety hazards:
Descriptions and photographs of unsafe gas piping, regulators, or controls on heating systems, indications of unsafe or improperly operating gas appliances, gas meters, and other gas installation defects.
This document also provides free sample draft home inspection report language for reporting defects in oil and gas piping at residential properties.
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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:
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.
Unsafe heating appliance conditions caused by backdrafting are discussed
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.
Examples of Easily-Detected Gas Leak Hazards
Photo at left: coated stainless steel gas appliance connector used for appliances & heating equipment.
Watch out when moving gas appliances: older flexible tubing may be thin-wall, corroded, damaged, and easily torn or caused to leak. Shut off the gas supply before moving appliances to minimize the hazard.
Here is a list of examples of other immediate LP gas or natural gas leak safety hazards that might be detected using a TIF8800™ Combustible Gas detector or using a soap solution and bubble testing:
You should have your plumber test/replace any suspect gas controls 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.
Old LP Gas Tank Leak Hazards
When inspecting old LP gas storage tanks above ground watch for corrosion, risk of rust perforation, and for leaks at control valves and fittings. Our photo below illustrates a rooftop LP gas tank installed in San Miguel de Allende, Mexico. Check the tank's date stamp and compare it with the tank ages permitted by local building codes.
Old Indoor Natural Gas Meter Hazards
Our photo below shows an older natural gas meter that is located inside of the building. This meter was originally outdoors but building expansion enclosed it. To meet current minimum gas safety codes (in New York State) the builder was required to add a vent pipe connecting the regulator (shown at left of the gas meter) to the outdoors.
The concern is that a rupture or damage inside the natural gas regulator at the meter might otherwise leak hazardous gas into the building interior. Coincidentally the meter is adjacent to a heating furnace - we would not want leaky gas to be transported through the building ductwork - increasing the hazards involved.
Abandoned or Old Gas Piping & Shutoff Hazards
When I saw this open-ended gas valve (below left) all I could say was @#$(*u&!
All that was needed for a catastrophic fire or explosion was someone ignorant of what this valve controlled to turn it in presence of a spark or flame, or to open the valve and leave it on. This natural gas line was live and could supply a virtually infinite quantity of explosive gas in the building.
Flexible Gas Appliance Connector Installation Procedures & Warnings
The manufacturer typically warns of the following safety hazards when using flexible gas connector tubing, mostly in the form of "Do Not" admonitions that we detail
Excerpts are below
What Chemicals are Used to Produce the Characteristic Odors in Natural or LP Gas?
Mercaptan is, according to our industry commentator J.R., a widely-recognized odorant, but only one of a number of similar-smelling products that are added to natural gas or bottled gas to assist in recognizing that a dangerous gas leak is present since natural gas alone, CH4 (Methane) is odorless.
Photo at left: an antiquated natural gas meter in the basement of a New York home.
The product added to natural gas to provide it with a characteristic odor is a mixture of tertiary butyl mercaptan, dimethyl sulfide and n-hexane.
Commonl y in the trades the gas odorant product is just called "mercaptan".
Mercaptan is added to natural gas at a rate of 0.08cc’s/1.0 m3 of natural gas.
Therefore very little mercaptan (or other gas odorant chemicals) in the gas stream.
Gas odorants are produced by Odor-Tech, a subsidiary of Arkema, by Chevron Phillips Chemical, and others. Odor Tech also produces Mercaptan Assassin ESD - an odorant-blend kit used to clean up mercaptan spills.
Critical Hazard Limits for Natural Gas or LP Gas
According to J.R., one of our industry correspondents, odorants need to be detectible in the natural gas at 1/5 the lower explosive limit (LEL), or more properly, the lower flammable limit or LFL.
So this is the amount of natural gas required in the test.
A person is exposed to very little natural gas in the air by the time they smell it.
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