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Natural gas  meter, antiquated, indoors (C) Daniel Friedman LP Gas & Natural Gas Safety
What to do if you smell gas, gas piping installation, inspection, testing & repair; gas controls, gas regulators & LP gas tank defects

  • POST a QUESTION or COMMENT about inspecting, testing, diagnosing, and repairing gas piping, gas regulators, and gas storage tank defects used with LP or natural gas burning appliances

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.

InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.

Immediate LP Gas & Natural Gas Safety Hazards

Coated stainless steel gas connector for appliances or heaters (C) Daniel FriedmanImmediate 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.

See GAS LEAK DETECTION, LP / NG for leak detection procedures and alternatives.

Unsafe heating appliance conditions caused by backdrafting are discussed

at BACKDRAFTING HEATING EQUIPMENT.

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.

Watch Out: 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 OIL TANK PIPING & PIPING DEFECTS.

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

Gas Odors: A gas leak can be indicated by gas odor such as in the utility area near appliances or elsewhere in the building. Leave the building and call for help from a safe location.

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 LP gas tank's date stamp and compare it with the tank ages permitted by local building codes.

Antiquated LP gas tank - watch for corrosion, out of date tank, leaks at valves & fittings (C) Daniel Friedman

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.

Natural gas meter installed indoors - buiding expansion may raise gas meter safety questions (C) Daniel Friedman

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.

Abandoned gas piping still live (C) Daniel Friedman

Flexible Gas Appliance Connector Installation Procedures & Warnings

Coated stainless steel gas connector for appliances or heaters (C) Daniel Friedman

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

at FLEXIBLE GAS CONNECTOR INSTALL.

Excerpts are below

What Chemicals are Used to Produce the Characteristic Odors in Natural or LP Gas?

Natural gas  meter, antiquated, indoors (C) Daniel FriedmanMercaptan gas odorant components, concentration strength, human exposure levels

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.

Mercury Hazards in Older Gas Service Regulators

This discussion got promoted to its own web page!

Please see MERCURY HAZARDS in APPLIANCES & GAS REGULATORS

LPG Propane & Natural Gas Safety Data Sheets

 




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Reader Comments, Questions & Answers About The Article Above

Below you will find questions and answers previously posted on this page at its page bottom reader comment box.

Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

On 2019-02-16 by (mod) - do older gas pressure regulators contain mercury?

Michael

This discussion got promoted to its own web page!

Please see MERCURY HAZARDS in APPLIANCES & GAS REGULATORS

On 2019-02-16 by Michael Soules

Do older gas pressure regulators leading to an individual gas appliance (gas fireplace, range, etc.) ever contain mercury? I know that older gas regulators leading into a home sometimes contain mercury, and would like to know if the pressure regulators for a single appliance can as well. (The specific situation I'm interested in involves a gas fireplace connected to a very old-looking pressure regulator.)

Here are the articles I've seen that discuss mercury pressure regulators: ... see the live link above - Mod.

Thank you for any thoughts!

On 2016-03-21 by (mod) - safety checks before turning on gas supply to new gas piping

Stephanie:

OPINION: The more components that are installed during gas line testing the more thorough and safe is your system test. There is, however, a standard for plumbing tests of gas piping for leaks that your plumbers should be able to cite and give to you.

I have found very common tiny leaks at the seam of gas regulators/valves on gas fired water heaters that no one takes as a concern.

When I have found leaks at a gas shutoff valve I've repaired or replaced the valve. Experts whose comments I've read agree with me that ignoring "small leaks" in a gas piping system (such as at shutoffs) is dangerous: who's to say the small leak today won't be an explosive leak or fire in the future?

And as you'll read in typical gas fired water heater testing instructions from a manufacturer, the manufacturer assumes the gas valves are in place:

"The appliance and its gas connection must be leak tested before placing the appliance in operation. It shall be isolated from the gas supply piping system by closing its individual manual Shut-off valve during any pressure testing of the gas supply piping system at test pressures equal to or less than 1/2 pound per square inch (3.5 kPa)."

And model codes and standards (cited below typically assume the gas valves are in place.

Watch out: "B. Before Turning Gas On. Before gas is introduced into a system of new gas piping, was the entire system inspected to determine that there are no open fittings or ends and that all valves at unused outlets are closed and plugged or capped? " - excerpt from North Dakota's NATURAL GAS SYSTEMS INSPECTION, TESTING, AND PURGING that in turn cites the standards given below.

I worry that your "cap it off and ignore the valves" plumber is making life too easy for herself.

See

On 2016-03-21 by Stephanie

Plumbers have given me contradictory advice about natural gas shutoff valves within a residence, at various appliances.

One plumber tells me that we should cap off the gas line to every appliance before pressure testing, since shutoff valves are very commonly responsible for low level leaks. Another plumber directly disputes that. Can anyone give me a sanity check on this claim?

(In our case, a plumber found a leak we were smelling in a gas line to one condo, then pressure tested gas lines to other condos and said most of them were leaking, although no one was smelling leaking gas elsewhere. That plumber tells us we have a big problem with leaks in the walls,

but a second plumber says that most likely the shutoffs were leaking due to the higher pressure when testing, and we likely don't have leaks within the walls. We are trying to decide whether to start cutting holes in walls looking for leaks there, or to cap off all the lines first at the shutoffs).

On 2014-06-04 by Anonymous

my Eternal tankless water heater makes a loud noise when igniting. So loud it rattles the neighbors windows. We use propane, and the unit is configured for it. What's the cause of this?

On 2014-04-03 by Mark Christopher

When converting a 90,000BTU furnace from Natural Gas to LP Gas (Propane), what can go wrong if the contractor installs the wrong size gas orifices? For example, if the proper LP Gas orifice is supposed to be size 1.15 (.0453 dia) ..what can happen if he installed size 54 (.0550 dia)? Specifically, can it cause excessive soot and eventually plug the heat exchanger?


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