Specification

How does a carbon monoxide alarm work?
It’s not like a smoke alarm. While a smoke alarm triggers an alarm when it
detects particles of smoke, a carbon monoxide alarm triggers an alarm based on
exposure to CO over time. It is designed to sound an alarm before an average,
healthy adult would experience symptoms.
Remember, with carbon monoxide, it is the concentration of CO over time that
poses a threat. Since carbon monoxide displaces oxygen in your blood, it can
harm you if you are exposed to either high levels of CO in a short period of time,
or to lower levels of CO over a longer period of time. Current UL limits for CO
exposure are:
o 30ppm for 30 days
o 150ppm for 10-50 minutes
o 70ppm for 60-240 minutes
o 400ppm for 4-15 minutes
If initial testing does not confirm the presence of carbon monoxide, there
may be other reasons for an alarm:
o Professional equipment used to measure the presence of carbon monoxide
in the air must be calibrated to sense low levels of gas concentration. Some
detection devices only measure concentrations of 1,000 parts per million
and higher, significantly above safe levels.
o If initial readings don’t reveal sufficient concentrations of carbon monoxide
to set off the alarm, testing equipment which registers levels over a 24-hour
period should be used to help identify the source.
o If doors or windows are left open or appliances turned off, and outside air
enters the home, carbon monoxide can dissipate. This can create a lower
reading than the original level that triggered the alarm.
o To help assure proper measurement, after evacuating the home, carbon
monoxide readings should be conducted by professionals as quickly as
possible after the alarm has sounded. To ensure the most accurate testing
by professionals, leave doors and windows shut after evacuating.
CAUTION: Do not reenter the premises until the emergency services responder
has arrived, the premises have been aired out and the CO alarm remains in its
normal condition.