Carbon monoxide alarms covered by UL listing standards, such as are sold in retail stores, may not be protecting your family from CO poisoning. They are not intended to alarm when exposed to long term, low level carbon monoxide exposures or slightly higher short term transient carbon monoxide exposures.
Are low levels of carbon monoxide safe?
Numerous studies show that low levels of CO are harmful. In fact, problems show up even at really low levels. A UCLA study found that CO levels above 5 parts per million (ppm) was associated with pregnant women having underweight babies with smaller heads.
The existence of such studies probably helps to explain the disclaimers that companies making UL listed CO alarms put on their products. Here's the warning from the Kidde-Nighthawk Model #KN-COPP-3, as given in the user manual I downloaded from the Kidde website:
“You should take extra precautions to protect high risk persons from CO exposure because they may experience ill effects from carbon monoxide at levels that would not ordinarily affect a healthy adult. Are there any infants or small children in the home? Be sure to check them for signs of possible CO poisoning because they might have trouble explaining their symptoms. Infants and children are more susceptible to CO poisoning than a healthy adult.”
Pregnant women should be aware that their unborn fetus could be harmed by exposure to carbon monoxide, even when the mother suffers no ill effect herself. Is there anyone in the household who is elderly, or who has anemia, heart disease or respiratory problems, emphysema or chronic bronchitis? These individuals are at higher risk for CO poisoning and for health problems from exposure to low levels of carbon monoxide.
Basically, the problem with UL listed alarms is that they're meant to offer protection to healthy adults during very high levels of CO in a home's air. So how much CO does a UL listed alarm allow you to breathe? Here's what UL standard 2034 allows:
- 30 ppm for up to 30 days
- 70 ppm for up to 4 hours
- 150 ppm for up to 50 minutes
- 400 ppm for up to 15 minutes
If you think about what those numbers mean, it's actually worse than it looks. For example, a UL listed CO alarm would allow you to breathe air with 358 ppm for 45 minutes—with NO alarm at all. Thirty days at 30 PPM could cause permanent organ damage! I don't know about you, but I'd rather have more protection than that.
The Environmental Protection Agency set the levels that are considered safe for humans at 9 ppm for 8 hours and 35 ppm for one hour for no more than once per year!
Long term exposure to even low levels of CO can be insidious and extremely serious. It can affect memory, brain function, behavior, cognition. It can also cause permanent damage to other major organs within the body, such as the heart.
Who is at risk from CO poisoning?
All people and animals are at risk for CO poisoning. Certain groups — unborn babies, infants, and people with chronic heart disease, anemia, or respiratory problems — are more susceptible to its effects. Each year, more than 400 Americans die from unintentional CO poisoning, more than 20,000 visit the emergency room and more than 4,000 are hospitalized due to CO poisoning. Fatality is highest among Americans 65 and older.
What can I do to protect my family?
I strongly recommend a low level CO alarm like The Defender. The Defender Carbon Monoxide Alarm doesn't have the approval from Underwriters Laboratories (UL) that so many products crave. And there's a good reason for that. The Defender monitor is a low-level monitor that tells you what's going on with the carbon monoxide levels in your home in real time. It cannot get listed by UL because UL has decided that only high levels matter. It continuously displays current CO levels of 5 ppm or more. At 10-14 ppm an additional alarm will sound 4 times every minute. If the CO levels increase, the alarm will sound more often, warning occupants to leave the home immediately.
How many Carbon Monoxide alarms do I need?
Install the first alarm in the immediate area of the bedrooms, then inside any bedroom where someone sleeps with the door closed or contains anyone who may be hyper sensitive to CO such as the elderly, pregnant women or children. Every level of a building should have a low level CO alarm.
How often should I change the batteries?
The Defender is supplied with sealed Lithium batteries that will last for over 5 years. The CO sensor becomes unreliable after that and the alarm should be replaced with a new one.
Low Level Carbon Monoxide Alarms.
One of the most important safety features of your home.
Sources: Allison Bailes, Energy Vanguard Blog
Defender Owner’s Manual