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Note: This Instructional Module information comes from our Training Manual. The complete Training Manual can be ordered from our Program and comes with a video, transparency masters, module publications, and many other educational resources.Module Learning Objectives
Support Publications
Videos (See "IAQ Video Sampler" included with the manual)
Notes to the Program Leader:Carbon Monoxide (CO) is a colorless, odorless gas that can cause death. It is produced whenever fuel is burned. Poisonings can occur when this gas collects in enclosed spaces such as homes or vehicles. While high doses of CO can kill quickly, low doses can cause disorientation that prevents remedial actions from being taken. Health symptoms are often mistaken for the flu. Common CO sources include blocked chimneys, malfunctioning heating equipment, the use of unvented or improperly vented fuel-fired heating appliances, or automobile exhaust entering an enclosed space. It is likely that many people suffer non-fatal health impairments from low-level CO exposure.Ideal audiences for this program include all households, especially those in heating climates, those using unvented, fuel-fired space heaters, and households with newly-changed heating systems. This presentation should take about 20 minutes. The format provides a series of overhead transparency masters and a script to accompany each visual. The script is in recitation form. This is to encourage you to present information in a conversational style and to avoid reading an exact script during the program presentation. For related information, see the "Combustion Pollutants in the Home"
module.
Script for Transparency #1 WHAT IS CARBON MONOXIDE? Carbon monoxide (CO) is a gas produced when any carbon-based fuel is burned. The amount of CO produced depends mainly on the quality or efficiency of combustion. A properly functioning natural gas or liquified petroleum gas (LPG) burner produces little CO, while an out-of-adjustment burner can produce life-threatening amounts without any visible indications. What really matters, though, is how this deadly gas is disposed of. If CO collects in an enclosed space, or if other conditions result in exposure to it, it can cause illness or death. A big problem is that the gas itself is odorless and colorless, so it can collect in spaces without our being aware of it. Some types of fuel (wood, oil) produce other combustion products (with odors) along with CO, so there can be some warning. These other pollutants can be dangerous as well and may be produced even when CO levels are not harmful. Proper maintenance of combustion appliances (furnaces, space heaters, ranges, ovens, gas water heaters, etc.) and their chimneys and flues is essential to preventing CO buildup indoors. It is important that service technicians test and adjust appliances using instruments that can measure CO productions. CO alarms can also aid in warning occupants of elevated CO levels. More information on CO alarms will be discussed towards the end of this presentation. Note to the Program Leader: For more information about combustion
products, see the "Combustion Pollutants in the Home" module.
Script for Transparency #2 CARBON MONOXIDE IMPACT According to the National Safety Council and the Centers for Disease Control and Prevention, about 500-1,000 people are killed in their homes each year by CO. It is likely that many more are harmed to some degree by this gas, but the extent is not known. A recent research study revealed that heart patients' emergency room
admissions had a small but significant correlation with changes in the
outdoor levels of carbon monoxide. It was concluded that episodes of elevated
outdoor CO can trigger emergencies in some heart patients exposed to this
gas. It is possible that elevated indoor CO levels may likewise trigger
problems in some heart patients. [Citation: Morris, et. al. Journal of
Public Health, Volume 85, p 1361, October 1995.]
Script for Transparency #3 CO SOURCE - FUEL BURNING
Script for Transparency #3A Note to the Program Leader: Use Transparency #3a at this point. COMMON SOURCES OF CO IN HOMES Accumulation of combustion gases usually happens when a blocked chimney, rusted heat exchanger, or broken chimney connector pipe (flue) prevents combustion gases from being exhausted from the home. CO can also enter the home from an idling car or other engine (generator or lawnmower) in the garage. Another scenario involves backdrafting; sometimes when ventilation equipment (such as a range-top vent fan) is used in a tightly sealed home, reverse air flow can occur in chimneys and flues. An operating fireplace can also have significant interactions with the flue dynamics of other heating appliances and backdrafting may result. Other common sources of CO include unvented, fuel-burning space heaters
(especially if malfunctioning) and the indoor use of a BBQ (charcoal).
CO is produced by gas stoves and ranges and can become a problem with prolonged,
improper operation (for example, if these appliances are used to heat the
home). A change in the gas flame's color can indicate a CO problem; if
a blue flame becomes yellow, CO will be increased. However, some blue flames
produce elevated CO levels as well, while some new appliances normally
have a yellow flame.
Script for Transparency #4 HEALTH EFFECTS - SYMPTOMS
CO victims must be removed from exposure as quickly as possible and require prompt medical attention. Because of the tight bond of CO to hemoglobin, recovery is not immediate when the victim is removed from exposure. Carbon monoxide will usually affect all occupants of a household at
the same time. This may be a good way of distinguishing it from the flu,
but it is important to realize that CO poisoning also impairs judgment
and such a realization may become difficult to attain.
Script for Transparency #5 INDOOR COMBUSTION APPLIANCES While larger combustion appliances are designed to be connected to a flue or chimney to exhaust combustion products, some smaller appliances are designed to be operated indoors without a flue. Appliances designated as supplemental or "decorative" heaters (including most unvented gas fireplaces) are not designed for continuous use. To avoid excessive exposure to pollutants, never use these appliances for more than four hours at a time. When operating unvented combustion appliances, safe practices must be carefully followed. Besides observing fire safety rules, make sure the burner is properly adjusted and there is good ventilation -- never use in a closed room, keep doors open throughout the house, and open a window for fresh air. Never use outdoor appliances (such as BBQs or construction heaters) indoors. Do not use appliances such as ovens and clothes dryers to heat the house. Inspect heating equipment. Make sure flues and chimneys are not blocked
to reduce the chances of backdrafting in furnaces, fireplaces, and similar
equipment. Inspect metal flues for rust; in furnaces, the heat exchanger
should be checked for rust and cracks. Soot is also a sign of combustion
leakage. When exhaust fans are used, open a nearby window or door to provide
replacement air.
Script for Transparency #6 SELECTING A CARBON MONOXIDE ALARM In recent years, CO alarms have become widely available in the consumer marketplace. When selecting a CO alarm, make sure it meets the stringent requirements of Underwriters Laboratories (UL), Inc. or the International Approval Service (IAS). These requirements are described in greater detail in the next overhead. Modern CO alarms can provide warnings for even non-lethal levels of this dangerous pollutant, but alarms should not be thought of as "the end all, be all" to alert you to dangerous CO levels in your home. The U.S. Consumer Product Safety Commission recommends having at least one CO alarm in every home, placed outside all sleeping areas. In considering such a purchase, make sure alarms have a long-term warranty, and can be easily self-tested and reset to ensure proper functioning. Consumer organizations such as Consumer Reports occasionally evaluate these devices. Look for the most recent articles on this subject. Here are some general points to consider before buying a CO alarm:
Script for Transparency #7 NEW STANDARDS FOR CO ALARMS A new standard for CO alarms took effect in October 1998. The new standard changes the designation of CO units from "CO detectors" to "CO alarms." Alarms are now required to sound at CO levels of 70 parts per million (the old standard was 100 ppm) and are prohibited from sounding or indicating at levels below 30 ppm (some older units were more sensitive). Alarms manufactured to these new UL and IAS standards give additional protection against acute, high levels of CO, but do not protect against CO levels below 30 ppm. When purchasing an alarm, consumers should look for one meeting the most current standards. Presently, alarms should bear the designation of either UL 2034 or IAS-696. Individuals with medical problems might consider using an additional detection device that has lower signaling capabilities. Note to the Program Leaders: False alarms: good/bad
news! Manufacturers and testing agencies continue to struggle with
a balance of adequate sensitivity and false alarming. Occupants need to
be extremely vigilant: Some CO alarms may still trigger when there is no
problem. At the same time, some "nuisance" alarms turn out to be the real
thing. Judgement needs to be used here: CO symptoms in any occupant means
that CO exposure may exist. If there are repeated alarms, it may be necessary
to vacate the home; otherwise have the home checked or use a new alarm.
Do not ignore "false" alarms; find out whether there is a problem or the
alarm is defective.
Prepared by:
 “www.healthyindoorair.org” is a partnership program of the Montana
State University Extension Service - Housing Program, U.S. Department of Agriculture - Cooperative State Research, Education, and Extension Service, the Healthy Homes Partnership - Alabama Cooperative Extension System @ Auburn University, U.S. Dept. of Housing & Urban Development, , and the U.S. Environmental
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