Sunday, April 1, 2007

Back Drafting: Carbon Monoxide Warnings

During a power outage caused by the windstorms in December 2006, a gas generator killed an entire family in Burien Washington. Carbon monoxide kills nearly 150 Americans a year. This statistic drove us to further research this topic. There are many possible sources of carbon monoxide in a home, and most people have no idea of the hazards they can pose.

We recommend anyone that uses gas, oil or wood appliances and fireplaces should heed these warnings to protect themselves and their families from this potentially fatal hazard. Furnaces, boilers, hot water heaters, fireplaces, gas ranges, gas grills, charcoal barbecues, cars, generators and gas powered tools are all common sources of carbon monoxide.


This hot water heater has exhaust rollout. Improper flue design or inadequate air supply can cause combustion
gasses to vent into the home. If your heater has these stains please have it checked out.

Controlling combustion appliance exhaust leaks.
When exhaust from appliances leak into homes the results can be very serious, even deadly. All types of heating systems with the exception of electric heat have the possibility of back drafting
gasses. Hot water heater, fireplaces, clothes dryers, gasoline powered vehicles and tools all produce toxic exhaust. Venting of these are crucial for removing hazardous
gasses from your home, and if improperly installed or maintained serious hazards can result.

Dryers, kitchen and bathroom fans, and window fans all force air out of the house and can be a source of "back drafting hazards". Care should be taken when fans are exhausting the house. These can cause a negative air pressure pulling
gasses backwards through their flue dumping combustion gasses in the home. With wood stoves or fireplaces, smoke being drawn into the living space is obvious. The evidence from other appliances is not always easy to detect. This problem has been more evident in today's tighter constructed homes. Older houses typically had more air leaks providing a fresh air supply for the fans. Carbon monoxide has no color or odor and therefore, we recommend carbon monoxide detectors in all homes.

In addition to carbon monoxide, other combustion
gasses can be a hazard. Carbon dioxide, nitrogen oxides and others are often present. In the case of nitrogen oxide exposure, there can be damage to lungs, exacerbate colds and cause respiratory illnesses. High concentrations of carbon dioxide will displace the vital oxygen supply in the home. Your best protection is to install carbon monoxide detectors that are approved by Underwriters Laboratories. Understand how they work, some are "hard wired" others are battery powered. As with smoke detectors, all battery powered detectors must be on a regular maintenance schedule changing the batteries and tested yearly. Remember, unlike smoke detectors, when a carbon monoxide detector goes off there is rarely any other evidence of the hazard. Don't make the deadly mistake in assuming that the unit is malfunctioning because there is no odor or smoke.

Carbon monoxide safety checklist.

  • Professional regular maintenance is the key. Common problems to check for include breaches in the heat exchanger, condensation in flues and proper exhaust drafting at startup.

  • All these appliance should have their burners checked to assure proper venting and combustion. A well adjusted burner produces much less carbon monoxide and provides more efficient heat.

  • In the case of an oil fired furnace this is likely to pay for itself. Oil burners require more precise adjustments and if properly maintained the efficiency will be optimal, saving precious fuel.

  • Make sure all combustion appliances have good supply of fresh air. When air supply is restricted they are much more likely to produce high levels of carbon monoxide and possibly have back drafting issues.

  • Modern sealed units draw fresh combustion air from outside. Consider replacing older style appliances with those that have their own dedicated air supply.

  • NEVER run cars, mowers, generators or other gas powered devices in homes or garages.

  • NEVER use gas grills or charcoal barbecues indoors.

  • Install carbon monoxide detectors - smoke alarms are not the same thing. Test them and change the batteries yearly. We recommend battery powered ones since many carbon monoxide deaths occur during power outages when people are most likely to attempt to keep homes warm with alternate heat sources.



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