FIRE PREVENTION AND PROTECTION FOR THE HOUSE OWNER
Chapter Four: Gas Safety

General
Many homes use natural gas to fire furnaces, water heaters, outdoor pool heaters and appliances (such as kitchen stove or clothes dryer). In addition, the use of propane for outdoor patio cooking is becoming increasingly popular. Both these forms of gas can be extremely dangerous and are potential sources of fire. The proper precautions must be taken when handling appliances using these forms of fuel.
Natural Gas
An underground distribution network feeds a metered supply of natural gas to your home. Natural gas is non-toxic but is explosive. It is lighter than air and usually has a strong odour added by the supply company, so that a leak can be easily and quickly detected. Although it is non-toxic, the products of combustion (fumes) are toxic and must be taken out of the building by the vent or chimney system. Most recent accidents involving gas appliances have been related to a faulty vent or chimney. For these reasons, rigid inspection procedures are adhered to, and all installations and modifications must comply with Canadian Gas Code B149.1.
Installation and modification Before embarking on the installation or modification of gas-fired appliances, homeowners should be aware that they are dealing with a potentially hazardous undertaking. It is recommended that you employ a professional gas fitter to install natural gas equipment in your home. However, if you do decide to do it yourself, it is important to note that inspections are required at several stages of installation, and that the gas must not be turned on until clearance is obtained from the gas inspector. Contact the Ministry of Labour Gas Inspection Office in your area for more information.
Furnace operation and maintenance Most gas-fired heating systems use a small, burning pilot light to ignite the main burner when the room thermostat calls for heat. As a safety measure, a device is installed in the furnace that will prevent gas being supplied to the main burner if the pilot light is out. You may wish to turn off the pilot light in the summer (a pilot light can account for 5-8% of yearly gas consumption). In any case, relighting the pilot light can be hazardous and it is recommended that a qualified gas fitter be called. If you find this is not practical and decide to do the job yourself, instructions for relighting the pilot usually appear on the furnace identification plate and should be followed very carefully. If, after following the relighting procedure, the pilot light fails to remain lit, a service mechanic should be called. Aside from changing or cleaning the air filter periodically, there is no other servicing operation that can be done safely by the householder. It is generally recommended that the furnace be serviced yearly, but the age and condition of the equipment, and the advice of a gas serviceman, will help you decide on the frequency of service. A brief yearly inspection is more economical if it can be combined with a necessary function, such as the relighting of the pilot after a summer shutoff. Air filters should be cleaned or replaced once a month during the heating season - they should be ULC approved and new filters should always be placed proper side up.
Other gas appliances If you have a gas-fired water heater (or other appliance), have the serviceman inspect it at the same time he inspects the furnace. He should take any steps necessary to ensure its safe and efficient operation. A gas fireplace must have the chimney damper permanently secured in the open position, even if the fire is not used.
Leakage A strong odour is added to natural gas by most supply companies for the protection of their customers. Fortunately, leaks are rare with modern gas equipment. However, if you suspect a leak, do not touch electric light switches or appliances and do not allow the lighting of any flame in the house. Open some doors and windows, clear the house and call the gas utility from a neighbour’s phone as soon as possible.
Propane
Propane, also known as Liquified Petroleum Gas or LP Gas, is a hydrocarbon chemical formed deep within the earth’s crust and brought to the surface, like other petroleum substances, through wells. Propane is non-toxic, odourless, and heavier than air. However, odour is added to ensure that its presence can be readily detected in the event of a leak. Propane is stored in liquid form, under pressure, in metal cylinders. When released with the proper controls, it comes out of the cylinder as a usable vapour. Because large volumes of propane gas can be stored as a liquid in relatively small cylinders, propane has become a convenient, portable form of energy. It is commonly used in the area of the home to fuel gas barbecues, but it may also be used for fuelling in-home appliances such as room heaters, refrigerators, gas ranges, water heaters and clothes dryers. Propane installations must comply with Canadian Gas Code B149.2.

For specific information on the installation and use of in-home propane appliances refer to a booklet entitled "Basic Instructions for the Operation of Simple Propane Gas Systems", distributed free of charge by the Propane Gas Association of Canada.
Storing and Handling Propane

Because it is so very combustible and under pressure, special precautions must be taken in handling, storing and using propane.

  • While propane cylinders are sturdily built, they should not be subjected to mechanical damage by dropping or rough handling - dents could weaken welded joints. Dented or corroded cylinders must be checked by a gas supplier to ensure their safety.

  • The outlet valve allows the gas to be turned on and off at the cylinder. It must never be exposed to damage and, on most cylinders, it is protected by a permanently fixed metal ring. Where there is no such ring, a protective metal cap must be screwed over the valve when moving the cylinder.

  • The pressure relief valve will release some of the propane vapour from the cylinder if the pressure inside the cylinder becomes greater than a preset limit. Such an event will occur if the cylinder is overfilled or if the temperature is high enough to expand the gas beyond its normal limits. If the relief valve is damaged or the nozzle is clogged so that it does not release at the proper pressure, the cylinder and/or fittings may rupture resulting in an extremely hazardous situation. The valve should never be tampered with.

  • Cylinders must always be upright, whether in storage, during transportation, or in use. This will ensure that, in the event of excess pressure, vapour escapes and not liquid propane. Liquid propane, released to the atmosphere, would immediately vapourize, expand 270 times in volume and be 270 times as dangerous as a vapour release.

  • Never store a propane cylinder indoors where there is a possibility it will be heated, expanding the propane and releasing it through the pressure release valve. This will cause an explosive situation in your home. In fact, cylinders over 5lbs capacity are not permitted to be used or stored in the home - if violation of this regulation was found to be the cause of a fire, your insurance could become void. Even in an unheated garage or shed, a release of vapour could occur waiting for a spark from a starting engine or scraping tool to ignite it. The best place to store propane is upright in a shady area, away from the house, protected from vandalism and physical damage. When stored, the outlet valve should be closed and a safety plug installed.

  • The regulator automatically opens and closes to ensure that the gas delivered to the appliance is at the required pressure. It is screwed into the cylinder outlet valve via a left-handed thread and must be wrench-tight. If the regulator is likely to be exposed to excessive sleet, snow, ice or mud, the vent opening on the regulator should be shielded to prevent plugging.

  • When appliances are not in use, the outlet valve should be completely closed, even when the cylinder is empty. This will prevent water vapour from entering the cylinder and causing possible freeze-up under freezing conditions.

  • When transporting propane cylinders to be filled take the following precautions:

    • plug the valve outlet with a plastic plug.
    • screw on the valve protection cap.
    • transport in a ventilated space in a vehicle trunk (preferably with the trunk open).
    • secure in an upright position.
Filling Cylinders should never be overfilled. When filled to rated capacity, there is always a vapour space left. This is important to allow for expansion of the liquid propane as the temperature varies. Some cylinders are equipped with a liquid-level bleed valve that indicates when rated capacity has been reached. If the liquid, through expansion, exceeds the volume of the cylinder, the relief valve would release liquid propane. Propane should not be transferred from one cylinder to another except at an approved station.
Maintenance Before being put into service for the first time, periodically during storage, and before every use, the system should be checked for leaks. This can be easily done by putting soapy water over hoses and connections - if bubbles occur there is a leak that must be corrected.

The regulator is preset to ensure that the proper pressure is delivered to your appliance. Never try to repair a regulator, or operate an appliance if the regulator is damaged in any way.

It is mandatory that a cylinder be requalified after ten years of service. Cylinders are date stamped, usually on the protective collar. To requalify the cylinder, it must be inspected and the valve and relief valve replaced by a qualified gas supplier. In practical terms, it is usually easier to simply buy a new tank because it costs about the same as replacing the valve and requalifying an older tank.
Leakage When propane gas escapes from a cylinder, hoses, connections or appliances, because it is heavier than air, it flows to the lowest point it can and accumulates on the floor. Because it is naturally odourless it is given a foul odour so that it can be detected when there is a leak. If you smell propane, take the following precautions.
  • remove all sources of ignition, such as cigarettes.
  • do not turn lights on or off as it could cause arcing and ignition
  • shut off all appliances and cylinder valves.
  • evacuate the area of all people.
  • provide as much ventilation as possible to allow the gas to escape an enclosed space.
  • if the leak continues after the valves have been shut off, seek qualified help (look under "Gas" in the Yellow Pages).
Purchasing and Using Propane Barbecues

This section also applies to other appliances that use propane, although barbeques are probably the largest single use of propane around the home - and the most potentially dangerous if the proper precautions are not taken.

 

  • Only appliances approved and certified by the Canadian Gas Association (CGA), Canadian Standards Association (CSA) or the Underwriters’ Laboratories of Canada (ULC) should ever be fuelled by propane. Where flexible hoses are required for portable systems, only approved synthetic hoses may be used. The appliance and hoses should bear an appropriate approval label.

  • It is recommended that you purchase a safety valve that monitors the amount of gas flowing through your propane system. The device is easily inserted between the outlet valve of the cylinder and the regulator. If the flow of gas increases beyond the preset capacity of the safety valve, due to a broken or ruptured line, the valve will instantly shut off the gas at the cylinder and prevent a hazardous situation.

  • Always locate the barbeque away from the house and any combustible wall or fence.

  • Hoses should never be a simple friction-fit, but should be wrench tight. Check all hoses and connections for leaks before lighting the burners. This can be done by fully opening the outlet valve on the cylinder, then putting soapy water over the hoses and connections - if bubbles occur there is a leak that must be corrected.

  • When properly connected, it is important to completely open the outlet valve on the cylinder when the appliance is in use. The outlet valve is not designed to regulate gas flow and may interfere with the proper operation of the appliance if partly closed.

  • Occasionally, some appliances may produce a slight odour for a short period when lighted, but which disappears rather quickly. If the odour persists, the appliance should be taken out of service until corrected.

  • Propane burns with a hot, clear, blue flame when mixed with the proper amount of air. The proper mixture of propane and air is very important. Occassional flashes of yellow, caused by dust particles, are no problem. If the flame is continuously yellow, it should be corrected, usually by increasing the air intake until the yellow disappears and the flame burns a clear blue.
Gas Detectors
If you have a Natural Gas or Propane appliance in your home (such as furnace, water heater, fire or stove) it is worth considering an alarm system that will warn you of a leak before an explosive situation arises. Gas fume detectors that are capable of sensing leaks from propane or natural gas equipment in the home are available at some gas equipment suppliers. They will sound a loud alarm well before dangerous levels of gas are present, and are usually easily installed by plugging into an electrical wall outlet.
Connection to a fire alarm system It is recommended that the alarm of the gas detector (which will usually be in the basement, close to the furnace) be extended into your overall fire alarm system to ensure that it will be heard in the living and sleeping areas of your home when activated. Types are available that can be hardwired from a compatible system alarm panel - with dc power supplied by the control panel. An alternative approach would be to place a fire alarm interface device (as described in Section 5.5.4) near a normal gas detector so that, when the detector is activated, it will "hear" the siren and send a wireless signal to the system alarm control panel for operation of the fire zone. For information on the features of a system alarm refer to Section 5.5.
Location The detector should be placed in close proximity to the furnace or other appliance to be monitored. Natural gas is lighter than air, so the detector should be placed on or close to the ceiling above the appliance being monitored. On the other hand, propane is heavier than air, so the detector should be placed close to the floor or ground near the appliance being monitored.
Testing and Maintenance Most gas detectors are equipped with a test button that will check the electrical circuitry of the device when pressed. A weekly test is advisable. At least once a year use a vacuum cleaner to remove dust from the openings of the detector. Refer to the instruction manual that comes with the detector for the proper maintenance procedure.
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