What Features Should I Look for When Purchasing a CO Detector?

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.

Here are some features to consider when purchasing a CO detector:

•  Look for a detector that is listed with the Canadian Standards Association (CSA) standard. The logos of the testing agency will be on the product.

•  Choose a detector with a memory if you want to monitor long term low-level exposure and short term, high-level exposure. Even though product standards do not allow manufacturers to display low levels of CO, these units monitor and store this information. Peak levels, no matter what the level of concentration, can be viewed by pressing a button.

•  Battery-operated units allow detector placement in the most convenient location. However, any battery-operated device requires the user's diligence in replacing worn-out batteries.

•  Do not connect plug-in units to an electrical outlet that is controlled by a wall switch.

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

Eventually, manufacturers may be required to print expiry dates on their CO detectors.This will ensure that you are purchasing an up-to-date product with a full sensor life.

Where Do I Put A CO Detector?

Most manufacturers specify where you should locate their CO detector. 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.

What do I do if I hear the CO detector 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.

Symptoms of CO Poisoning 2

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.

Testing A Carbon Monoxide Detector

Most CO detectors have a test button that should be pressed once a week to confirm that the device is in operation. Detectors with displays can be tested with a known source of CO such as smoke from a cigarette or incense stick. Hold the CO source about 8-10 inches away and watch the digital display respond to the presence of even a small amount of CO. BUT an alarm will most likely not sound with this test.

There are CO detector test kits available, where CO detectors are sold, that provide a vial of high level of CO (1000 ppm) and a plastic tent to house the unit during the test. This test only proves that your detector will sound an alarm with a very high level of CO.

Changes In Test Standards

The standards organizations of Canada (CSA) and the United States (Underwriter's Laboratory or UL) have co-ordinated the writing of CO standards and product testing. The standards as of 2005 prohibit showing CO levels of less than 30 ppm on digital displays. The new standards also require the alarm to sound at higher levels of CO than with previous editions of the standard.The reasoning behind these changes is to reduce calls to fire stations, utilities and emergency response teams when the levels of CO are not life-threatening.This change will also reduce the number of calls to these agencies due to detector inaccuracy or the presence of other gases. Consequently, new alarms will not sound at CO concentrations up to 70 ppm. Note that these concentrations are significantly in excess of the Canadian health guidelines.

Detectors with a digital display and a history option can provide the true CO concentrations in a house. A low-level display would be useful for people with existing respiratory problems or for those who like to spot evolving problems, rather than having to wait for the situation to become serious. Low-level CO detection products are becoming commercially available. They will not be certified to CSA or UL standards, as these standards currently prohibit low level displays.

1 Exposure Guidelines for Residential Indoor Air Quality , Health Canada, 1989.

2 From CAN/CSA 6.19, Residential Carbon Monoxide Alarming Devices , 2001