Unlike fire alarms, which are dormant most of the time and only sound an alert when actual smoke or flames are present, a carbon monoxide detector is constantly active, even when the alarm isn't ringing. An easy distinction is in the names. One is an alarm, and the other is a detector; this means it is regularly monitoring your home.
Carbon monoxide is a colorless, odorless gas. Even with low to moderate levels of exposure, carbon monoxide (CO) poisoning can occur and lead to neurological damage and even death. Because of this, it is crucial that you understand how to read your carbon monoxide detector, so you know whether or not carbon monoxide is reaching and staying at dangerous levels in your home.
Getting an Accurate Read
To make sure that the reading on your carbon monoxide detector is accurate, you first need to make sure it is installed in an appropriate location. Most manufacturers will recommend installing a CO detector near the ceiling. this is because while carbon monoxide is close to the same weight as air, it most often comes from fuel burning appliances that will emit warm carbon monoxide. Being warmer, the gas tends to rise above the air.
Also, because the odorless gas is a by-product of any fuel burning appliance, you should not install a carbon monoxide detector directly above or beside these types of appliances. Because they have a tendency to emit a “burst” of carbon monoxide on start up, they may give your detector an inaccurately high reading if is too close.
Understanding the Carbon Monoxide Measurement
Carbon monoxide is measured in parts per million, often abbreviated as PPM, which is a measurement used to describe diluted fluids in water or gases in air. This is a similar measurement to a percentage. For example, one percent, which is one out of 100, is the same thing as one part per hundred. Thus, if one percent of the air in a room was made up of carbon monoxide, that would be equivalent to 10,000 parts per million of carbon monoxide.
Knowing How Much Is Too Much
The numbers on your carbon monoxide detector probably don't mean much to you if you don’t know how many parts per million is safe and how much is dangerous. While there are no exact concentrations for what you can handle, there are some general guidelines to follow.
A good baseline for what is safe is around 35PPM, which is the maximum concentration allowed by federal law for continuous exposure over an eight-hour period. After two or three hours of exposure at 200 PPM, you can experience mild headaches, dizziness, or nausea.
It starts to really get dangerous at 400PPM, which not only can cause severe headaches after only one or two hours of exposure, but also can become life threatening after more than three hours of exposure.
It gets drastically worse from here, with 1,600 PPM causing death in one hour and 10,000PPM causing death in under 10 minutes.
Worrying Only When You Need to
One of the important things to remember when checking your carbon monoxide level is that a high number is not always an immediate indicator of a gas leak. For levels up to 200 parts per million, you can leave the home (after turning off all carbon monoxide producing appliances, of course) for a few hours and return to see if the reading remains the same. Often something as simple as a nearby smoker will cause the reading to spike up to 100 parts per million.
However, if the reading is continuously at or above 35 parts per million, your are at high risk for carbon poisoning and immediate action should be taken, even if your carbon monoxide detector’s alarm is not sounding.