How To Deal With Suspected Gas Leak

craftman

                                 Natural and more efficient than electricity on the whole, gas is a popular choice of fuel for the home. However, some people have an inherent mistrust of gas, given its toxic nature. If you're scared of the possibility of a gas leak going undetected in your home, feel reassured that there are clear warning signs. Oz Plumbers presents your vital guide to gas leaks.

How to spot a gas leakIf you suspect a gas leak in your home, there are a few things to check first. Familiarise yourself with the smell of gas, as this will be your first port of call (detecting the presence of gas' very distinctive odour). An odour is added to gas before it's piped into your home, to improve ease of recognition. You might hear a "hissing" sound if a leak is strong. This would indicate an extremely dangerous type of leak and you should evacuate your home immediately in such a case, before calling the emergency services. If you don't hear a sound but the test dial is turning when no gas appliances are on, it's also possible that you have a leak. In such a case, turn off the gas meter and contact your licensed gasfitter or plumber to have your gas installation checked. For safety reasons, don't work on any gas pipes or appliances yourself.

What to do in the event of a gas leakIf you suspect a gas leak, there are a few things you should do. Firstly, extinguish all flames. Turn off any appliances and pilot lights, and be sure to switch off the gas supply at the outside meter. Open doors and windows for ventilation and, if the smell persists or grows stronger, evacuate your home. In the case of an emergency, phone 000 - but ensure that you are away from the affected area when you make the call.

Everyday gas safetyTaking everyday precautions can help prevent gas leaks occurring in the first instance. It's wise to always be vigilant when it comes to gas, but specifically:

• Don't fix or service gas appliances yourself - leave it to the professionals (also have them service your appliances regularly)
• Don't leave any inflammable materials (such as clothes or paper) near gas appliances or burners, or blocking permanent ventilation openings
• Don't force gas taps to open and only use appliances for the purpose in which they were intended (for example, don't dry your socks in the oven)
• Keep your gas oven and hot plates clean - don't allow fat or food debris to build up
• Turn off gas heaters when you leave the house or head to bed. Only use such appliances when you can keep your eye on them
  

This list isn't exhaustive and there are plenty more ways to keep your home safe from the threat of gas leaks. Given its potentially lethal nature, if you're in any doubt whatsoever regarding your gas supply's operation, it's best to be extra cautious and speak to a certified expert.
A little awareness can aid quick response, which is essential for any gas leak. Once you can detect a gas leak (in particular by familiarising yourself with the smell of unburned gas), you'll be able to deal with it in the appropriate way.

http://www.ozplumbers.com.au/how-to-spot-a-gas-leak

                       

craftman

How to find leaks in gas piping: How to Identify & Correct LP Gas or Natural Gas Leaks
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Detect or find gas leaks in natural gas or LP gas / propane piping, fittings, & appliances: This article describes how to find gas leaks on LP or natural gas piping, regulators, or appliances, and it provides free sample draft home inspection report language for reporting defects in oil and gas piping at residential properties. This article series  provides descriptions and photographs of unsafe gas piping, indications of unsafe or improperly operating gas appliances, gas meters, and other gas installation defects are provided.
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How to Test or Look for LP Gas System Leaks

Here we outline some common procedures used to test gas piping and fittings for leaks. These procedures should work equally well for bothLP gas (propane or bottled gas) systems and for natural gas (piped-in gas from a gas utility company) systems. Watch out: 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. 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. NOTE: Except that LP gas and natural gas operate at different pressures and thuswill have different test pressure specifications. Readers who are interested in gas leak detection equipment should review our article and gas testing warnings at Recommendations for gas measurement instruments & gas detector tubesfor indoor gas level tests which includes our description of use of the TIF8800 and similar gas detectors. Our photo at  above left of an  LP gas line shutoff shows black staining around the shutoff valve and flare fitting, with some of the black worn away - previously there had been an LP gas leak at this location.

General Safety Warnings for LP or "bottled" or "propane" Gas Installations & InspectionsImmediate 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.
Pressure testing a gas piping system for evidence of gas leaksThese two methods are generally used to test a gas piping distribution system to see if leaks are present.

• Low Pressure Method Gas leak tests by gas service technicians generally include the following steps:
  
  • All gas piping connections, valves, and appliance connections and valves are inspected visually for tightness and good condition
  • A gas pressure gauge [such as the Fisher™ Type 50P-2 gas pressure gauge] is connected to a burner orfice
  • The gas service valve is opened to permit gas to flow into the gas piping distribution system, and then the valve is closed again, securely
  • The gas pressure gauge should read eight inches of water column in pressure (previously 9 inches, earlier eleven inches of water column) and should hold steady.
  • The gas pressure at the point of testing, say a gas-fired heating appliance, is bled off slowly until the gas pressure test instrument gaugeindicates nine inches of water column.
  • The system is monitored for any pressure drop for at least three minutes. If no pressure drop is detected the system is considered not leaking.
    
• High pressure gas leak method is also used by gas service technicians and includes steps similar to those above, using a specialfitting [such as the Fisher(TM) Type J600 test block] installed between the service valve outlet port at the LP gas tank. The service valveis opened,as above, to pressurize the gas piping, and the system is bled down to a test pressure of 10 psig, then monitored for at leastthree minutes to check for a pressure drop.
  

Thanks to reader Tony Martinez for updating our data on the proper pressure for LP or Natural Gas leak testing. Thanks to another reader JR, an industry manager familiar with gas pressures, who adds that  these two fuel gases operate at different pressures. In residential appliances

• Natural Gas system pressure: Natural gas operates at a nominal pressure of 7” WC (about 0.253 psi)
• LPG or Liquid Propage Gas system pressure: LP gas or propane operates at a nominal pressure of 11” WC (about 0.397 psi)
• Actual NG or LPG gas pressures vary: [Note: the exact pressure you see in the building at an appliance may vary from these numbers depending on the gas distribution piping system size, diameter, number of appliances served, number of appliances operating, regulator adjustment, and other factors. See Gas Regulators for Appliances and Gas Regulators for LP Tanks. See LP or Natural Gas Pressures for a table showing the range of variationin LP gas pressure in the tank at various temperatures. - Ed.]
  

and adds:
Watch out: Extinguish gas pilot lights - in order to perform pressure-testing methods for LP or natural gas leak detection as discussed above, you will need to extinguish the pilot lights on all gas-fired appliances in the building, and the pilot lights will need to be re-lit again after testing is complete.


Methods used to find and identify points of gas leaks in a gas piping distribution system or at a gas appliance

Visual Inspection for Evidence of Gas Leaks in fuel gas lines and appliances:Our photograph shows black stains on copper tubing at the flare fitting connecting an LP gas line to a shutoff valve. Some service technicianspoint to stains on piping as an evidence of a possible chronic leak in the gas line at this point.

• Gas odors observed during gas piping inspection: The mercaptan put into LP gas and natural gas is inserted there by thegas company as a safety feature so that people may notice that they have a dangerous (explosive) gas leak intheir home. Some people may confuse this odor with a septic tank gas odor.See Diagnosing and Curing Sewer Gas Smells and Septic Tank Odors for a discussion ofsewer gas odors.
• "Soap solution" bubble tests for gas leaks: a solution of soapy water (some technicians use dish soap and a brush or rag) is the mostcommon method used to test for gas leaks. As we noted earlier, Readers who are interested in gas leak detection equipment should review our article and gas testing warnings atRecommendations for gas measurement instruments & gas detector tubesfor indoor gas level tests which includes our description of use of the TIF8800 and similar gas detectors.
• Soap solution is applied at every piping joint or connection (or the test instrument may be used carefully at and around everyconnection or other suspect point) and the technician watches the soaped connection to see if soap bubbles are formed. Experts warnthat this method requires some experience and care. For example, a large gas leak may blow away the solution without forminga soap bubble, or bubbles may be forming in a location which is physically hard to see.(Sometimes we can "see" around a corneror to the back side of a pipe using our TIF 8800 combustible gas detector in these cases.)
• Soap solution is applied along gas piping to lengths of piping to test for pinholes or mechanical damage if no leaks are found at threadedor flared connectors but when gas leaks are evident in the system.
• Gas leaks at gas valves: we very often find very small gas leaks at the seamed sides of some gas valves, such as those commonlyfound on gas-fired domestic water heaters, especially when using the TIF 8800. These leaks can be so miniscule that they do not show upduring a bubble test, and they are often present even on new valves. This may be a source of some disagreement between a home inspector,building owner, and the gas service technician, and need to be handled with some judgment, experience, and reason.
  

Identifying Sources of Leaks at Brass Flare Fittings on LP Gas Piping SystemsHere are two brass flare fittings. One of them had a gouge that gave us a gas leak that was a bit tough to find untilwe disassembled and inspected the leaky joint.
If tightening flared copper tubing connections does not easily correct a leakat that joint, do not just over-tighten the joint (you may break the flare and cause a still larger leak), and do notrely on pipe sealant inside of flared copper tubing fittings.
Open and inspect the flare fitting joint, and replace the flare fittings ormake a new copper tubing flared end if necessary.
Also see Advice for Making Flare Fitting Connections with Copper Tubing or Piping where we describe preparation of the flare joint for flexible copper tubing for refrigeration or gas piping lines.