Kidde KN-COSM-B-RF User Manual page 21

AC powered alarms (without battery backup) will not operate
if the AC power has been cut off, such as by an electrical fire
or an open fuse.
Smoke alarms must be tested regularly to make sure the
batteries and the alarm circuits are in good operating condition.
Smoke alarms cannot provide an alarm if smoke does not
reach the alarm. Therefore, smoke alarms may not sense fires
starting in chimneys, in walls, on roofs, on the other side of a
closed door or on a different floor.
If the alarm is located outside the bedroom or on a different
floor, it may not wake up a sound sleeper.
The use of alcohol or drugs may also impair one's ability to
hear the smoke alarm. For maximum protection, a smoke
alarm should be installed in each sleeping area on every level
of a home.
Although smoke alarms can help save lives by providing an
early warning of a fire, they are not a substitute for an insurance
policy. Home owners and renters should have adequate
insurance to protect their lives and property.
Carbon Monoxide Alarm
The carbon monoxide (CO) alarm monitors the air for the
presence of CO. It will alarm when there are high levels of CO
present, and when there are low levels of CO present over a
longer period of time. When a CO condition matches either
of these situations, the alarm/voice message warning system
will sound and be accompanied by the flashing red LED. The
carbon monoxide sensor uses an electrochemical technology.
Product Features and Specifications − Carbon Monoxide Alarm 21