Carbon monoxide (CO) is one of the leading causes of unintentional poisoning deaths in the United States. The US Consumer Product Safety Commission (CPSC) states: "Every year, over 200 people in the United States die from CO produced by fuel-burning appliances (furnaces, ranges, water heaters, room heaters). Others die from CO produced while burning charcoal inside a home, garage, vehicle or tent. Still others die from CO produced by cars left running in attached garages. Several thousand people go to hospital emergency rooms for treatment for CO poisoning.
It is terrible to have lives lost when a small amount of prevention could have saved them. That prevention is a functional carbon monoxide (CO) detector, also called a CO alarm, installed in your RV. If you don't currently have a CO detector in your rig, I'm going to try to convince you that you need one. In fact, by the end of the article, I hope to convince you that CO can pose a real threat to your health and, indeed, your very life.
"Because it takes several hours for the body
to remove carbon monoxide, CO is a cumulative poison."
You've Got Gas
CO is a highly toxic gas that can kill at small concentrations of 300 parts per million (ppm) or less. Carbon monoxide gas is produced when fossil fuel burns incompletely because of insufficient oxygen. Properly installed and maintained fuel-burning appliances produce only small amounts of carbon monoxide, but malfunctioning appliances can be deadly. Anything that disrupts the burning process or results in a shortage of oxygen can increase carbon monoxide production. Wood, coal and charcoal fires always produce carbon monoxide, as do gasoline engines.
Potential sources of CO in or around your RV can include a malfunctioning propane furnace or ventless heater, exhaust from a generator or gasoline engine or a wood or charcoal-fired barbecue or stove. (See RV CO source diagrams on the next page.)
Because of their smaller living spaces, RVs can be even more dangerous if CO is present because a smaller space increases the concentration of carbon monoxide. For instance, operation of a defective, unvented gas heater in a 1,680-square foot home might raise CO levels to 30 ppm. In a 200-square foot RV, the same heater could quickly raise the CO concentrations to a dangerous 200 ppm or more.
Colorless, Odorless, Tasteless
The fact that CO is a colorless, odorless, tasteless and non-irritating poison, compounds the problem. Without a CO detector, you'll never be aware that CO is present until it has begun to affect you. When exposed to high concentrations, persons become dizzy, are unable to stand or move to fresh air and often collapse. The brain does not receive sufficient oxygen during a CO exposure, resulting in confusion.
Because it takes several hours for the body to remove carbon monoxide, CO is a cumulative poison. The amount of CO in the body continues to increase while breathing CO in the air. Occupational Safety and Health Administration (OSHA) places the maximum allowable concentration for continuous exposure for healthy adults in any eight-hour period at only 50 ppm!
Not convinced yet? Well, consider this: Gas kitchen ranges release unvented combustion products into the interior of your RV. The amount of CO in combustion products varies widely, from a few ppm from a properly operating gas burner, to 20,000–30,000 ppm from an improperly operating gas burner.
Contrary to popular belief, carbon monoxide can, and often is, produced from a blue-burning flame. Using the range hood to exhaust the combustion products, along with cooking odors, grease and moisture produced during cooking, is a great idea, and you should never use the range burners to heat the rig. However, the vent may not be enough to protect you from carbon monoxide exposure.
Many RVers who dry-camp have installed unvented propane space heaters. These units are terrific for saving propane and battery power, but they can be a source of indoor air pollution, and that includes CO.
Oxygen Depletion Sensors
When properly maintained and adjusted, gas heaters produce low amounts of CO. One cause of carbon monoxide poisoning from unvented heaters—incomplete combustion caused by lack of air—has been virtually eliminated in newer heaters by use of oxygen depletion sensors (ODS). Unfortunately, the ODS does not respond to incomplete combustion caused by improper gas pressure, dust, dirt or rust on the burner or disruption of the burner by air currents. Even a properly maintained and adjusted vent-free heater can cause dangerous levels of CO inside an RV if adequate ventilation is not provided.
Carbon Monoxide Safety Resources
For those of you who have access to the Internet, there are a number of excellent informational sites on CO and safety.
• Highly recommended is the Iowa State University Extension site for carbon monoxide information
• Another outstanding site for CO information is authored by David G. Penney, Ph.D., professor of physiology and adjunct professor of occupational and environmental health at Wayne State University, Detroit, MI
For more information, you might want to check out these agencies:
Here are some online links to CO detector sources and manufacturers:
• American Sensors
• Atwood Mobile Products
• First Alert
• Marine Technologies, Inc.
• Quantum Group, Inc.
Standard RV forced-air furnaces are safe, as all combustion gases are vented outside the rig by a forced-air blower system. However, as these units age, the furnace combustion chamber can corrode or split, causing combustion byproducts to enter the RV and build up. In the case of such a malfunction, without a functional CO detector installed in your rig, your only early warning signal will be the onset of flu-like symptoms, nausea or dizziness as the levels of CO rise. You may fail to recognize these symptoms as warnings of CO poisoning until it is too late.
Still not convinced that you need a detector? If you have a generator installed in your rig or use a portable unit, you need a detector even more!
The National Institute for Occupational Safety and Health (NIOSH) ran a 5.5-horsepower gasoline-powered pressure washer in a double garage with both doors open, the window open and a vent open. In only 12 minutes, CO concentrations in the garage rose to 658 ppm. The rate of emission from a typical gasoline engine is so large (30,000 to 100,000 ppm) that it is difficult to provide sufficient ventilation.
NIOSH warns, "Do not use equipment and tools powered by gasoline engines inside buildings."
Even with a properly installed exhaust system, carbon monoxide from your running generator, or even your neighbor's, can still enter your rig through small cracks or waft into your rig through an open window.
As the above NIOSH test proves, just because the windows in your rig are open doesn't necessarily protect you from potentially dangerous concentrations of carbon monoxide.
I hope all the above has convinced you to protect yourself by installing a CO detector. They are not terribly expensive, and even the best ones will set you back less than a tank of fuel.
Detectors are easy to install, operate, and will give you peace of mind along with serious protection.
I believe the best detector to purchase is one with a digital display. That lets you monitor even lower levels of CO that may be too low to cause an alarm but high enough to be dangerous with long-term exposure. Most detectors with digital readouts also capture and hold the peak CO reading since the last reset. This is worth keeping an eye on, too.
The National Safety Council (NSC) states: "You should not choose a CO detector solely on the basis of cost; do some research on the different features available. Carbon monoxide detectors should meet Underwriters Laboratories Inc. standards, have a long-term warranty and be easily self-tested and reset to ensure proper functioning."
The RV environment is hard on CO detectors, due to exposure to heat, humidity and exhaust gases while rolling down the road. While any detector is better than no detector, your best bet is to purchase one that is UL-listed for RV use.
Are you back from the store? Do you have your new detector in hand? Let's install it! Read the manual and install the batteries. Pick a location on the wall that is approximately at eye level.
Since CO is not significantly lighter or heavier than air, it tends to disperse evenly. Make sure the detector is not behind curtains or furnishings. CO must be able to reach the detector for the unit to work. It's best to avoid installing the detector very close to the kitchen stove or propane heater, and keep it out of moist bathroom areas.
A single detector placed centrally in your rig will provide reasonable protection, but you may want to place one in your sleeping area as well.
Follow the instructions in the user manual that came with your unit. Test it regularly and keep it free of dust and dirt. Then it will continue to provide you with peace of mind for years.
This is a very important article by Mark Nemeth that has been updated and is a reprint from Escapees Magazine issue January/February 2005. RVers should pay close attention to this topic especially as we get closer to the end of summer and start turning those heaters on in the fall.
Have fun and stay safe on the road, and please send your RVing questions to [email protected].
Mark Nemeth has been involved with all things RV for more than ten years, including almost 5 years on the road as a fulltimer. Nowadays, Mark is parked for a while and works on staff for the Escapees RV club as technical advisor, consumer affairs director, and instructor in the Escapees RVer's Boot Camp program.
Do you have a question for Mark?
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Some content previously printed in Escapees magazine, published by the Escapees RV Club. All material provided by Mark Nemeth, Escapees Magazine Technical Advisor and Boot Camp Instructor. For more information about the Escapees RV Club, please visit www.escapees.com or call 888–757–2582.