Combustion Safety

Combustion safety is an often-overlooked but important issue in today's homes.  If you  have a gas water heater, gas furnace, gas range, gas stove or gas logs, you have a combustion appliance and it produces combustion gasses.  These combustion gasses include carbon dioxide, particulates, nitrogen dioxide, water vapor and, if there is incomplete combustion, carbon monoxide.

Combustion by-products have adverse effects on health including:

• Eye, nose and throat irritation
• Possibility of early termination of pregnancy
• Possibility of impaired lung function and respiratory problems in young children

However, the major problem is carbon monoxide - at low levels it can produce nausea, dizziness and flu-like symptoms.  At higher levels carbon monoxide can be fatal.

Combustion appliances are either open flame or sealed combustion.  The newer, more efficient water heaters and furnaces are sealed combustion with no open flame;  these are way safer and much more efficient than the older models.  You can tell if you have a sealed combustion water heater or furnace if the pipes coming out of the appliance are plastic PVC pipe.  Many of the furnaces in central North Carolina, even the newer ones, are the less-efficient, open flame furnaces with metal pipes coming from the appliance.

If open combustion appliances are in the living space of a house, they should be tested.  Combustion gasses and carbon monoxide can be backdrafted into the house by:

• Kitchen and bath fans
• Clothes dryers
• Leaky HVAC ducts
• Whole-house fans

In addition, water heaters can have flame rollout, which is where the gas flame is pulled outside the heater and obviously can cause a fire.

Combustion safety testing involves checking for carbon monoxide, testing for combustion gas spillage, checking for worst-case depressurization of the house and how it affects the appliances plus checking for gas leaks.

In addition to combustion safety testing, if you have gas appliances, you should have carbon monoxide monitors.  The recommendation is for one alarm per sleeping area, one alarm for each level of the house, and one alarm in each area with a fireplace or other combustion appliance.