What Do Carbon Monoxide Detector Numbers Mean?

What the Numbers Measure

• The numbers displayed by carbon monoxide detectors indicate the amount of carbon monoxide in the air. Carbon monoxide is odorless and invisible to the naked eye. This gas is commonly produced by burning fuel, such as kerosene but can come from other sources as well.

The Measurement System

• Carbon monoxide detectors measure in parts per million. This indicates the number of carbon monoxide gas particles per one million particles of air. A measurement of 1,000 ppm would indicate that the concentration of carbon monoxide was at .10 percent.

Significant Values

• The concentration levels of carbon monoxide that are considered safe depend on how long an individual will be exposed and under what concentration. Federal allows exposure at 35 ppm for periods of up to 8 hours. Higher concentrations of carbon monoxide will induce dizziness and nausea within two or three hours and eventually lead to death.

How to Get Accurate Readings

• Understanding the numbers produced by a carbon monoxide detector is only useful if they are accurate. To ensure accurate readings be sure to mount detectors at a moderate distance from appliances that are likely to generate carbon monoxide fumes. Many devices that operate with open flames create short spikes of carbon monoxide fumes when they start that will trigger a CO detector. It is generally recommended that CO detectors be mounted near the ceiling due to the fact that carbon monoxide fumes frequently rise from heat generated by their source.

Causes of Inaccurate Readings

• Inaccurate readings from carbon monoxide detectors are frequently caused by temporary spikes of carbon monoxide. While these readings do accurately reflect the temporary increase in carbon monoxide. Since CO detectors are most efficacious when used to detect overall levels of carbon monoxide, it is handy to know what may cause a temporary spike in readings. Sources that utilize an open flame commonly create a burst of carbon monoxide when they turn on. Cigarette smoke can also cause a sudden increase in CO readings.