How Do I Help Prevent CO Poisoning?
First, as noted in Part I of last month’s carbon monoxide post, install CO detectors in your home and replace them as needed. Next, make sure that all fossil fuel burning appliances are professionally and properly installed and regularly maintained. Furnaces, non-electric water heaters and boilers should be serviced annually by a qualified HVAC professional or licensed plumber. Doing this helps ensure these appliances are installed and operating properly and are safe to use.
Fireplaces, furnaces, boilers, non-electric water heaters, etc. need to vent their exhaust gases into a chimney or be direct-vented to the exterior. If any of these appliances vent into a chimney, the chimney should be professionally cleaned/inspected annually. From my experience, most homeowners never have their chimneys cleaned as they don’t think this maintenance is needed. Leaves, debris and animal nests can block a chimney and force the appliances’ exhaust gases to back up into the home. This is a common cause of CO injuries and deaths. Once your chimney has been professionally cleaned/inspected, a rain cap should be installed on top to prevent future leaves/debris and animals from entering and potentially blocking your chimney.
Vent-free gas and propane (LP) fireplaces do exist, and I run across them from time-to-time in my home inspection travels. These units don’t have an exhaust vent (no connection into a chimney) and are designed to fully burn the fuel. These units have an oxygen depletion sensor which is supposed to detect if the room’s air lacks oxygen due to high CO levels. I’ve heard of instances of these sensors failing, so I don’t recommend vent-free appliances inside the home. Some states forbid vent-free fireplaces altogether. Vent-free appliance manuals tell the user to open a window in the room that the appliance is located in to ensure sufficient combustion air, although virtually no homeowners read or heed this warning.
Next, never operate things like generators or grills inside the home, basement or garage. They need to be used outside in a well-ventilated area. Also, only operate vehicles in a garage with the garage door fully open. Never use a gas or LP stove/oven to heat your home.
If you have a fireplace, ensure that the damper is open before starting the fireplace. If the fireplace is gas or LP and has a running pilot light and your fireplace has a damper, a special clip should be installed to ensure that the damper cannot be fully closed. Carbon monoxide can fill your home simply due to a running pilot light with no ventilation (closed fireplace damper). Cleaning solvents, such as paint thinner, should only be mixed or used outdoors as they can also produce CO in some areas.
Ensuring that your furnace, water heater, etc. have sufficient combustion air is critical. I find many homeowners finish their basements without permits and then wall around the portion of the basement where a furnace and/or non-electric water heater are located. These appliances need sufficient oxygen to properly and safely operate. Modern building standards stipulate the minimum size of a room where fossil fuel appliances are installed and how much fresh air the room must have. This sizing is based upon the type and BTU ratings of the appliances in the room. I’ve seen numerous instances of homeowners tightly closing off furnaces and water heaters with drywall and then also storing things like boxes, paint cans and other combustible items in these small rooms. If the stored items don’t starve the appliances for oxygen, they can readily catch fire if a fossil-fuel burning appliance were to malfunction. If finishing a basement, start by getting a permit as this is generally required in almost all cases nowadays in our area. Then ensure the utility room (where the furnace, water heater, etc. are located) is large enough to ensure proper appliance operation and combustion air and that this room’s walls have proper upper and lower vents to ensure needed air flow. Don’t store items near the appliances.
Attached garages are required to have fire-separation, also commonly called a firewall. Properly installed, mudded and taped drywall should separate the garage from living spaces and attics. One purpose of the fire-separation is to help slow a garage fire’s quick spread into the home, but another is to help prevent garage carbon monoxide from entering living space. For any place where wiring, ductwork or plumbing penetrates garage walls or ceilings, these areas should be properly sealed. There should be no heating registers in the garage since a fire or carbon monoxide can readily get into living space via the ductwork, even if the register is closed.
Pulldown ladders should not be installed in attached garages as they compromise the fire-separation and are not air tight to the garage attic space. If there is an access panel to a garage attic, the panel cover should also be a fire-rated material like drywall. Plywood, OSB and particle board, etc. are not fire-rated and will burn in the event of a garage fire. Some areas of the country even require self-closing garage mandoors into living space as this prevents a door from the garage from being accidentally left open where a fire or carbon monoxide can enter the home. However, to my knowledge no cities or townships in our area require self-closing garage mandoors.
Preventing carbon monoxide poisoning is fairly easy to do when homeowners use common sense and have at least one CO detector in their home; however, there are still many people unfamiliar with the risks, the symptoms and the causes. As you can see, it is critical that if you are exposed to carbon monoxide that you act quickly. This means moving to fresh exterior air and calling 911. Minutes can be the difference.
Matthew Steger, ACI, WIN Home Inspection
Facts, opinions and information expressed in the Closing Comments Blog represent the work of the author and are believed to be accurate, but are not guaranteed. The Lancaster County Association of Realtors® is not liable for any potential errors, omissions or outdated information. If errors are noted within a post, please notify the Association. Posts represent the author’s opinion and are not necessarily the opinion of the Association.