Carbon Monoxide
How does a CO detector work?
What standards apply to CO detectors?
Do CO detectors require maintenance?
Are they required?
What do I do if my detector sounds an alarm?
Carbon monoxide (CO) is a colourless, odourless, tasteless and toxic gas. It can inhibit your blood's ability to transport oxygen through the body. It can poison you quickly when in high concentrations, or slowly in low doses. Exposure to CO can cause flu-like symptoms such as:
- headaches,
- nausea,
- dizziness,
- burning eyes,
- confusion,
- drowsiness, and
- loss of consciousness.
Carbon monoxide is a common by-product of the combustion process. Improperly installed, maintained or vented appliances can produce CO. Pay special attention to:
- gas or oil furnaces and hot water heaters,
- gas appliances,
- fireplaces,
- woodstoves,
- charcoal grills, and
- space and kerosene heaters.
Blocked chimneys and obstructed vents can result in the accumulation of CO.
Detectors can sense unsafe levels of CO and will sound an alarm.
How does a CO detector work?
Most commercially available detectors for home installation use biometric, metal-oxide semi-conductor (MOS) or electrochemical technologies.
Biometric detectors are also called biomimetic, colourimetric or gel-cell detectors. A photoelectric eye in these detectors senses colour changes in a chemically treated disk of gel. This design mimics the body's response to CO absorption. These detectors can be battery powered.
Detectors that use metal-oxide semi-conductors require more energy and need to be plugged-in or hard-wired. They use a heated metal-oxide semi-conductor to detect CO.
Electrochemical technology usually involves an acid electrolyte solution and platinum electrodes. The presence of CO causes a chemical reaction that instigates a current flow through the circuit. These units' low energy consumption allows them to be battery-powered.
Remember the lessons learned from the ice storm of 1998-electric-operated units will not protect your family during extended power outages. Consider installing electric and battery operated units or dual-powered detectors.
What standards apply to CO detectors?
The two main industry standards used in Canada are CAN/CGA-6.19, "Residential Carbon Monoxide Detectors," and UL2034, "Single and Multiple Station Carbon Monoxide Detectors." Units should bear the approval of one of these standards. Electric-powered units should also bear the CSA approval.
In general, current standards require detectors to alarm for 70 ppm within 240 minutes, 150 ppm within 50 minutes and 400 ppm within 15 minutes.
Earlier CO-detector models were designed with different standards. Recent changes to detectors primarily address false alarms common with the older models. Revisions to these standards do not make current carbon-monoxide detectors obsolete.
Do CO detectors require maintenance?
CO detectors should be maintained in accordance with the manufacturer's instructions. Keep your air vents clean by vacuuming them occasionally. Test the detectors regularly. In general, units should be tested at least once a month.
Are they required?
The Ontario Building Code requires CO detectors in newly constructed homes with solid-fuel burning appliances such as woodstoves and fireplaces.
CO detectors are not mandatory in all Ottawa homes. A home heated by electricity with no other possible sources of carbon monoxide does not need a detector.
Ottawa Fire Services supports voluntary installation of detectors and recommends you install at least one detector in your home.
What do I do if my detector sounds an alarm?
Call Ottawa Fire Services. If anyone is suffering from CO-poisoning symptoms, leave the home immediately. The firefighters will investigate the alarm and will take CO measurements. If they suspect the problem is related to gas-fired appliances such as a furnace or hot-water heater, they will request the gas company to respond. Be prepared to answer some questions; your information may help determine the cause of the alarm.
Often, whatever may have caused the alarm may not be present when the firefighters arrive. For example, a motor vehicle may have been running in the garage and the carbon monoxide from the exhaust may have entered the home and triggered the alarm.
