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Building Science by Norman Aceron Garcia

Carbon monoxide alarms

by Norman Aceron Garcia

Carbon monoxide alarms

Carbon monoxide (CO) is a colourless, odourless, poisonous gas that originates from incomplete combustion of fossil fuels, wood or coal. Lethal concentrations of carbon monoxide can build up in an enclosed space without the occupants knowing it. Therefore, where an enclosed space has or is close to a potential source of carbon monoxide, it is important to provide means of detecting and warning occupants of its concentration.

When carbon monoxide is breathed in, it damages the sensitive organs, such as brain, heart and lungs, by replacing the oxygen that would normally bind with hemoglobin. High concentrations of carbon monoxide can kill a person in less than five minutes and can also attack gradually over a period even in small concentrations.

There are two common potential sources of carbon monoxide: fuel-burning equipment and attached storage garages. Any malfunctioning or improperly installed fuel-burning equipment can be a source of carbon monoxide, such as furnaces, room and space heaters, stoves and ovens, water heaters, fireplaces and wood stoves, gas and charcoal grills, vehicles, power tools that run on gasoline, and boat engines. Although the building code requires that the walls and floor/ceiling assemblies separating attached garages from dwelling units include an air barrier system, there have been numerous occurrences of carbon monoxide from garages leaking into houses.

If there’s an attached storage garage or fuel-burning equipment installed in the house, carbon monoxide alarms must be installed in the service room and in every bedroom or outside each bedroom within five metres of the bedroom doors. Carbon monoxide alarms installed in houses with a secondary suite are required to be interconnected. This is to ensure that if one alarm is triggered, the other alarms will activate too. Battery-operated carbon monoxide alarms are acceptable as long as they are mechanically fixed to the wall or ceiling.

How can you prevent carbon monoxide poisoning?

  • Buy and install carbon monoxide alarms that meet the requirements of CAN/CSA-6.19, “Residential Carbon Monoxide Alarming Devices.” They must be installed at a height and locations required by the manufacturer and the local building code. If the carbon monoxide alarm is powered by the house’s electrical system, there should be no disconnect switch between the alarm and the circuit’s overload protection device.
  • Do not attempt to repair or clean the fuel-burning appliances without the proper knowledge, skill and tools. Refer to the manufacturer’s instruction manual when doing minor adjustments.
  • Do not use any fuel-burning equipment, such as portable generator and camping equipment, either in or near an enclosed space.
  • Do not burn charcoal inside a house and garage.
  • Do not let a vehicle run idle inside the attached garage.
  • Do not operate unvented fuel-burning equipment.
  • Have chimneys and fireplaces serviced regularly.
  • Check external vents are not blocked by debris, dirt or snow.

In summary, carbon monoxide is a hazardous gas that can be formed by a variety of household appliances and equipment. Carbon monoxide alarms must be installed strategically throughout the home or building in order to warn occupants of high concentrations of the gas.

Norman Aceron Garcia, P.Eng. is an accredited professional in Leadership in Energy and Environmental Design specializing in Building Design + Construction. In 2015, Norman founded Mr. Peg Property Inspections, a social enterprise that advocates green building design and climate change adaptation strategies.

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