Carbon Monoxide

Symptoms of CO Poisoning

Be sure that all members of your family know the symptoms of CO poisoning:

  • Mild Exposure: Flu-like symptoms such as headache, running nose, sore eyes, etc.
  • Medium Exposure: Drowsiness, dizziness, vomiting.The sense of disorientation and confusion may make it difficult for some victims to make rational decisions like leaving the home or calling for assistance.
  • Extreme Exposure: Unconsciousness, brain damage, death.
  • Continued Low-level Exposure to CO: While this may be not lead to observable symptoms, you should still avoid such exposure.

How to react to an alarm

Do not ignore the CO detector's alarm if it sounds. Treat each alarm as serious and respond accordingly.

CO detectors are designed to sound an alarm before a healthy adult would feel any symptoms. Infants, the elderly and those with respiratory and heart conditions are at particular risk and may react to even low levels of CO poisoning (Health Canada, 1989).

Response To An Obvious Source Of CO

If your detector sounds an alarm and you have an obvious source of CO, such as an unvented kerosene heater:

  • Evacuate the house, including pets and do a head count.
  • If anyone is suffering from flu-like symptoms, call 911.
  • Remove or turn off the source.
  • Ventilate the house.
  • reset the alarm.
  • Do not re-occupy the house until the alarm ceases.
  • Take steps to avoid this situation in the future.

Response To An Unknown Source Of CO

If your CO detector is sounding an alarm and there is no obvious source of CO:

  • Evacuate the house, including pets and do a head count.
  • If anyone has flu-like symptoms, call 911; if there are no health problems, call your gas utility, heating contractor or the fire department to have your house tested.
  • If you live in a single family home: do not ventilate your home, turn off fuel-burning appliances or reset your CO detector prior to someone testing your home.*
  • If you live in a duplex, row house, apartment, or otherwise attached house, do ventilate the house and turn off fuel-burning appliances. In this case, the safety of your neighbours is more important than trying to find the CO source.
  • Have a qualified service technician inspect and repair all fuel-burning appliances, if they are identified as being the CO source.
  • Do not re-occupy the house unless those who tested the house inform you that the danger is over.

* Many CO alarm calls have been classified as "false alarms". because the homeowner has ventilated the home and turned off the equipment before firemen or technicians can measure the CO levels and find the source.

Carbon Monoxide

Carbon Monoxide (CO) is a very dangerous gas that must not be present in your home. Preventing it is something very important for the safety of your home. We will go over what this gas is, how to prevent it's entry into your home and about CO detectors that must be installed in your home.

What is it?

Carbon Monoxide (CO) is a colourless and odourless gas Since you can't see, taste or even smell it, it can affect you and your family without you even knowing it's there. Even at low levels of exposure, CO can cause serious health problems. What this gas does is accumulate in the blood, replacing oxygen in your system. This depletes the ability of blood to carry oxygen, and you die of asphyxiation.

Where does it come from?

Carbon monoxide is a by-product of the combustion(burning) of fossil fuels. Most fuel-burning equipment (natural gas, propane and oil),if properly installed and maintained produces little CO. The by-products of combustion are usually safely vented to the outside. However, if anything disrupts the venting process (such as a bird's nest in the chimney) or results in a shortage of oxygen to the burner, CO production can quickly rise to dangerous levels.

The burning of wood, kerosene, coal and charcoal produce CO. Gasoline engines produce CO. CO production is at a maximum during the startup of a cold engine. Starting, then idling, your car or gas mower in the garage can be dangerous.The fumes that contain CO can enter a home through connecting walls or doorways and can quickly rise to dangerous levels.

Eliminating Threats

The most important step you can take to eliminate the possibility of CO poisoning is to ensure that CO never has an opportunity to enter your home. This is your first line of defence. Review this list to minimize the risk of CO in your home.

  • Have a qualified technician inspect and clean fuel-burning appliances yearly, before the cold weather sets in, to ensure they are in good working order.
  • Have a qualified technician inspect chimneys and vents yearly for cracks, blockages (e.g., bird's nests, twigs, old mortar), corrosion or holes.
  • Check fireplaces for closed or blocked flues.
  • Check with a qualified technician before enclosing heating and hot water equipment in a smaller room, to ensure there is adequate air for proper combustion.
  • If you have a powerful kitchen exhaust fan or downdraft cooktop, have a qualified technician check that its operation does not pull fumes back down the chimney.
  • Never use propane or natural gas stove tops or ovens to heat your home.
  • Never start a vehicle in a closed garage; open the garage doors first. Pull the car out immediately onto the driveway, then close the garage door to prevent exhaust fumes from being drawn into the house.
  • Do not use a remote automobile starter when the car is in the garage; even if the garage doors are open.
  • Never operate propane, natural gas or charcoal barbecue grills indoors or in an attached garage.
  • Avoid the use of a kerosene space heater indoors or in a garage. If its use is unavoidable provide combustion air by opening a window while operating. Refuel outside after the unit has cooled.
  • Never run a lawnmower, snowblower, or any gasoline-powered tool such as a whipper-snipper or pressure washer inside a garage or house.
  • The use of fossil fuels for refrigeration, cooking, heat, and light inside tents, trailers, and motorhomes can be very dangerous. Be sure that all equipment is properly vented to the outside and use electric or battery-powered equipment where possible.
  • Regularly clean the clothes dryer ductwork and outside vent cover for blockages such as lint, snow, or overgrown outdoor plants.
  • Reduce or eliminate the use of fondue heaters indoors.
  • If you live close to a road with heavy traffic, outdoor carbon monoxide levels can affect your indoor air quality, especially during rush hour. Such levels should not set off a CO alarm, but slightly elevated CO levels might be observable on some types of CO detectors with a digital display.

CO Detectors and how they work

There are three basic types of CO sensors metal oxide, biomimetic and electrochemical.

  • Metal Oxide Semi-conductor (MOS): The original technology for detecting CO. Heated tin oxide reacts with CO to determine the levels of the toxic gas. It must be connected to house powers. Because of this, there is no need to remember to check batteries, but they also have battery backup of up to 20 hours in case of blackout.
  • Biomimetic: Gel-coated discs darken in the presence of CO. Colour change sounds an alarm. This is less expensive, and can be either battery operated or plugged in to the house power.
  • Electrochemical: Chemical reaction with CO creates an electrical current, setting off an alarm. This type is highly sensitive and gives accurate readings at all CO levels. Most units of this type come with a continuins digital readout and a memory feature that allows you to check past levels of CO. It has a fast reset time and most units sound an alert when sensor needs replacing.

There are performance differences between these detector types. However, changes to the CO standards have resulted in all detectors, regardless of detector type, having to undergo extensive testing. All are certified to operate under different environments (various chemical exposures, different relative humidities, etc.) satisfactorily if they meet the standards.

Most CO detectors are designed to give an alarm when CO levels reach a high-level in a short time. However, health agencies advise that long term, low-level exposure are also of concern, especially for the unborn and young children, the elderly and those with a history of heart or respiratory problems (Health Canada, 1989). Detectors that can display both high and low levels are more expensive but they do provide greater accuracy and more information.

No detector will operate properly forever. Replace them at least every five years, unless the manufacturer specifies a shorter or longer life.

Where to put it

In general, the best place to put the detector is where you will hear it while sleeping. CO is roughly the same weight as air and distributes evenly throughout a room, so a detector can be placed at any height in any location, as long as its alarm can be heard. Additional units could be installed in several other locations around the home, such as a child's bedroom; check the list below before installing.

To avoid both damage to the unit and to reduce false alarms, do not install CO detectors:

  • In unheated basements, attics or garages.
  • In areas of high humidity.
  • Where they will be exposed to chemical solvents or cleaners, including hair spray, deodorant sprays, etc.
  • Near vents, flues or chimneys.
  • Within 2 metres (6 ft.) of heating and cooking appliances.
  • Near forced- or unforced-air ventilation openings.
  • Within 2 metres (6 ft.) of corners or areas where natural air circulation is low.
  • Where they can be damaged, such as an outlet in a high traffic area.
  • Where directly exposed to the weather.

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