Fire Safety
Limitations of Smoke Alarms
WARNING: Please read carefully and thoroughly.
• NFPA 72 states: Life safety from fire in residential occupancies
is based primarily on early notification to occupants of the
need to escape, followed by the appropriate egress actions
by those occupants. Fire warning systems for dwelling units
are capable of protecting about half of the occupants in
potentially fatal fires. Victims are often intimate with the
fire, too old or young, or physically or mentally impaired
such that they cannot escape even when warned early
enough that escape should be possible. For these people,
other strategies such as protection-in-place or assisted
escape or rescue are necessary.
• Smoke alarms are devices that can provide early
warning of possible fires at a reasonable cost; however,
alarms have sensing limitations. Ionization sensing
alarms may detect invisible fire particles (associated
with fast flaming fires) sooner than photoelectric alarms.
Photoelectric sensing alarms may detect visible fire
particles (associated with slow, smouldering fires)
sooner than ionization alarms. Home fires develop in
different ways and are often unpredictable. For
maximum protection, Kidde recommends that both
ionization and photoelectric alarms be installed.
• A battery powered alarm must have a battery of the
specified type, in good condition and installed properly.
• A.C. powered alarms (without battery backup) will not
operate if the A.C. 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, walls, on roofs, on the
other side of a closed door or on a different floor.
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