Carbon Monoxide and How it can Affect Your Home
Every year, all over North America, there are stories in local papers about Carbon Monoxide incidents in homes, many times with resulting fatalities or illness. According to the Center for Disease Control, Carbon Monoxide (CO) is the largest cause of poisoning in the United States. Each year an average of 544 Americans are killed by accidental exposure to CO, and another 7,000 to 15,000 people are hospitalized.
Experts agree that Indoor Air Pollution is one of the most serious health concerns we face. And of all the possible indoor contaminants, Carbon Monoxide is the most hazardous. At high levels, CO can be deadly in minutes, and is often referred to as "The Silent Killer".
Also quite disturbing is recent evidence showing that exposure to low levels of CO over time can compound many pre-existing health problems such as heart and lung disease, anemia, diabetes, asthma, depression and learning and concentration problems. It can also be responsible for premature death.
Unfortunately, low-level CO poisoning can be very difficult to diagnose because its early symptoms are similar to those of the common cold or flu. Some of the common symptoms of CO poisoning include headaches, fatigue, confusion, chest pain, nausea, rapid heartbeat and difficulty breathing. One member of a family can be suffering while others are not affected. Children and elderly persons are often the most affected.
Knowing where this insidious poison can come from and how it can be prevented from accumulating in your home is extremely important.
Where Does CO in Homes Come From?
There are many potential sources of Carbon Monoxide. Carbon Monoxide, which is a colorless, tasteless and odorless gas, is a product of incomplete combustion. Burning of any fuel can produce CO.
Furnaces, Boilers and Water Heaters?
The sources most often thought of by homeowners are vented gas or oil furnaces, boilers or water heaters that, for one reason or another, malfunction and fail to vent their combustion by-products out of the building. Although these appliances are often found to be the cause of CO incidents, recent data shows that they are not the most prevalent. In fact they appear to represent less than 25% of the incidents.
According to a recent utility company study, the number one cause of CO alarm calls is from CO leaking into homes from attached garages. When an automobile engine is started it puts out very high levels of CO. Even if the car is backed out relatively soon after starting, if the garage door is then closed, high levels of CO can be trapped in the garage. In many homes, over the next few hours the CO will find its way into the house through many potential leakage pathways. Some of these pathways into the home are cracks around the entry door and framework, gaps and cracks in drywall, wiring and plumbing penetrations and leaky ductwork, just to name a few.
Gas Ovens and Ranges
The second leading cause of CO alarm calls is gas ovens and ranges. This particular combustion appliance is one that is seldom vented to the outside. Therefore the potential for elevated CO levels in the house air is very likely if the appliance is producing CO.
Unvented Heaters or Fireplaces
Other sources that can be responsible for elevated CO levels in homes are unvented combustion appliances, such as kerosene or gas space heaters, or malfunctioning wood stoves or fireplaces.
CO can also be produced by power equipment such as lawn mowers, chain saws, forklifts, generators, etc. Pool heaters, BBQ grills, trash incinerators, tobacco smoking and propane powered refrigerators in hunting/fishing camps can also be sources. Even electric ovens have been known to set off CO alarms in their self-cleaning mode.
What Can You Do to Make Your Home Safer?
Have A Whole House Comfort Checkup Performed
An Infiltrometer blower door test will determine the tightness level of your home and duct system. It will pinpoint air leakage sites between the house and garage: pathways for CO transport into the building. Once they are uncovered, these leaks sites should be sealed. In some cases, passive or mechanical ventilation of the garage is recommended. Ask the contractor to analyze whether dangerous negative pressure could be created in your home from the operation of exhaust fans, clothes dryers and closing of interior doors.
Have Your Furnace, Boiler and Water Heater Maintained Annually
Proper tuning and maintenance should be done routinely on all combustion appliances to ensure they are burning cleanly, and venting their by-products to the outside. Ask your contractor to test for CO production using an electronic CO analyzer, and make adjustments as needed to ensure a clean burn. Also ask that the "draft" be tested to ensure that the combustion gases are venting up the chimney. Ask for an inspection and leakage test of the furnace heat exchanger. If you have a gas oven, have it tested for CO production as well.
Use A Kitchen Exhaust Fan If You Have A Gas Range
It should draw air from the kitchen and vent to outdoors. A hood over the range is preferred. (A "recirculating" hood that simply passes the air through a charcoal filter will not help.) The fan should be used whenever the range top burners or oven are being used. This helps to ventilate and dilute any CO before it can reach unsafe levels.
Never Use A Gas Oven To Heat Your Home
The potential for elevated CO greatly increases the longer the oven is on. If you do have to use it during a power outage, make sure that nearby windows are cracked open, and have a battery powered CO alarm in the home.
Remove Any Unvented Heater Or Fireplace
Comfort Institute recommends against using any "unvented" gas or kerosene heaters, fireplaces or gas logs. Apart from the possibility of CO being created, they produce many other unhealthy combustion byproducts that you and your family should not breathe. They also can produce large amounts of water vapor, which can cause condensation, moisture damage and mold growth. If you choose to keep them in your home (e.g. for emergency heat), be sure to ensure proper ventilation during operation (at least use an exhaust fan or crack open some windows during operation).
Never Use A Charcoal Or Propane Barbecue In A Home Or Garage
There have been any tragedies during power outages involving barbecues used inside. Don't take the risk.
Be Careful When Using A Wood-Burning Fireplace
Wood smoke contains high levels of CO. Be sure the damper is left open for at least 12 hours after the fire has died. Ensure a CO alarm is present in the home. Crack open a window at least one square foot when the fire is burning to reduce the negative pressure in the home created by its draft. (This negative pressure can cause water heaters or furnaces to back up.)
Install A "Sealed Combustion" Furnace Or Water Heater
Certain more advanced and more energy efficient furnaces, boilers and water heaters are less susceptible to "backdrafting". This occurs when negative pressures are created in the home (typically by exhaust fans, clothes dryers and even closing interior doors when the furnace fan is running). Ask your CI member contractor for guidance.
Install A Carbon Monoxide Detector/Alarm
Even with the best possible preventive maintenance and testing, there are circumstances beyond our control and our ability to predict. Therefore, we recommend that at least one Carbon Monoxide alarm be installed in every home, generally in the hallway outside the bedrooms. Homes with multiple sleeping areas should have more than one. Comfort Institute recommends that at least one be battery operated in the event of a power outage. An added benefit is that CO alarms often detect fire before conventional smoke detectors.
There are several makes and models of CO alarms on the market. Your CI member contractor can help you determine the best choice of alarm and the appropriate location(s) for installation. They may even be able to supply and install them for you.
Comfort Institute also recommends that you bring a battery powered CO alarm with you while traveling. There have been many tragedies in hotels over the years from malfunctioning appliances such as pool heaters. Recreational vehicles or catalytic heaters that use propane are also a cause for concern.
What Should We Do If Our CO Alarm Goes Off?
If you should ever experience a CO alarm situation in your home, the first thing to do is make sure all people and pets exit the building. Then call a qualified contractor immediately to investigate for the cause of the alarm.
Carbon Monoxide Analyst Certification
Look for a contractor who has attained Carbon Monoxide Analyst Certification by Building Performance Institute (BPI). The Building Performance Institute is a national non-profit technical certification organization that offers a certification in Carbon Monoxide analysis. This certification is your assurance that this contractor has the advanced training, knowledge and experience to fully investigate the cause of an alarm, to determine the source of the problem and to recommend proper corrective action. Comfort Institute is working closely with BPI and is encouraging all CI member contractors to become certified. Your local CI member contractor may have achieved this certification, or may be able to recommend someone who does.
Do not accept a "false alarm" diagnosis and not give it another thought. While CO alarms have been known to occasionally go off without CO being present, in the vast majority of cases CO was present. If your analyst can't pin down the cause with certainty, invest in additional CO alarms for comparison, and pay very careful attention to any further response.
At least one manufacturer makes a CO alarm that monitors very low levels of CO and displays the current and peak readings on a digital display, as well as the time elapsed since the highest reading. This can be very useful when trying to identify an intermittent source. Ask your CI member for information.
NEVER remove the battery or disconnect a CO alarm if it is giving intermittent alarms that can't be figured out. See attached newspaper article on a tragedy that occurred in New York in June of 2000.
CO Poisonings Can Be Prevented
Carbon Monoxide is an unfortunate reality. No home is immune. CO poisonings have occurred in leaky homes as well as tight homes, and have occurred in all electric homes.
However, CO tragedies can be almost entirely prevented. Use this information to protect yourself and your family. Feel free to copy this information for friends, family, neighbors and co-workers.
Document C-SRT-108 Version 1.0
For distribution only by Comfort Institute Members in good standing
Reproduction and Distribution By Non Members Strictly Forbidden