Fire Alarm & Emergency Communication System Limitations
While a life safety system may lower insurance rates, it is not a substitute for life and property insurance!
An automatic fire alarm system—typically made up of smoke
detectors, heat detectors, manual pull stations, audible warning
devices, and a fire alarm control panel (FACP) with remote notifi-
cation capability—can provide early warning of a developing fire.
Such a system, however, does not assure protection against
property damage or loss of life resulting from a fire.
An emergency communication system—typically made up of
an automatic fire alarm system (as described above) and a life
safety communication system that may include an autonomous
control unit (ACU), local operating console (LOC), voice commu-
nication, and other various interoperable communication meth-
ods—can broadcast a mass notification message. Such a
system, however, does not assure protection against property
damage or loss of life resulting from a fire or life safety event.
The Manufacturer recommends that smoke and/or heat
detectors be located throughout a protected premises following
the recommendations of the current edition of the National Fire
Protection Association Standard 72 (NFPA 72), manufacturer's
recommendations, State and local codes, and the
recommendations contained in the Guide for Proper Use of
System Smoke Detectors, which is made available at no charge
to all installing dealers. This document can be found at http://
www.systemsensor.com/appguides/. A study by the Federal
Emergency Management Agency (an agency of the United
States government) indicated that smoke detectors may not go
off in as many as 35% of all fires. While fire alarm systems are
designed to provide early warning against fire, they do not
guarantee warning or protection against fire. A fire alarm system
may not provide timely or adequate warning, or simply may not
function, for a variety of reasons:
Smoke detectors may not sense fire where smoke cannot
reach the detectors such as in chimneys, in or behind walls, on
roofs, or on the other side of closed doors. Smoke detectors also
may not sense a fire on another level or floor of a building. A sec-
ond-floor detector, for example, may not sense a first-floor or
Particles of combustion or "smoke" from a developing fire
may not reach the sensing chambers of smoke detectors
Barriers such as closed or partially closed doors, walls, chim-
neys, even wet or humid areas may inhibit particle or smoke
Smoke particles may become "cold," stratify, and not reach
the ceiling or upper walls where detectors are located.
Smoke particles may be blown away from detectors by air
outlets, such as air conditioning vents.
Smoke particles may be drawn into air returns before reach-
ing the detector.
The amount of "smoke" present may be insufficient to alarm
smoke detectors. Smoke detectors are designed to alarm at var-
ious levels of smoke density. If such density levels are not cre-
ated by a developing fire at the location of detectors, the
detectors will not go into alarm.
Smoke detectors, even when working properly, have sensing
limitations. Detectors that have photoelectronic sensing cham-
bers tend to detect smoldering fires better than flaming fires,
which have little visible smoke. Detectors that have ionizing-type
sensing chambers tend to detect fast-flaming fires better than
smoldering fires. Because fires develop in different ways and are
often unpredictable in their growth, neither type of detector is
necessarily best and a given type of detector may not provide
adequate warning of a fire.
Smoke detectors cannot be expected to provide adequate warn-
ing of fires caused by arson, children playing with matches
(especially in bedrooms), smoking in bed, and violent explosions
(caused by escaping gas, improper storage of flammable materi-
Heat detectors do not sense particles of combustion and alarm
only when heat on their sensors increases at a predetermined
rate or reaches a predetermined level. Rate-of-rise heat detec-
tors may be subject to reduced sensitivity over time. For this rea-
son, the rate-of-rise feature of each detector should be tested at
least once per year by a qualified fire protection specialist. Heat
detectors are designed to protect property, not life.
IMPORTANT! Smoke detectors must be installed in the same
room as the control panel and in rooms used by the system for
the connection of alarm transmission wiring, communications,
signaling, and/or power. If detectors are not so located, a devel-
oping fire may damage the alarm system, compromising its abil-
ity to report a fire.
Audible warning devices such as bells, horns, strobes,
speakers and displays may not alert people if these devices
are located on the other side of closed or partly open doors or
are located on another floor of a building. Any warning device
may fail to alert people with a disability or those who have
recently consumed drugs, alcohol, or medication. Please note
An emergency communication system may take priority over
a fire alarm system in the event of a life safety emergency.
Voice messaging systems must be designed to meet intelligi-
bility requirements as defined by NFPA, local codes, and
Authorities Having Jurisdiction (AHJ).
Language and instructional requirements must be clearly dis-
seminated on any local displays.
Strobes can, under certain circumstances, cause seizures in
people with conditions such as epilepsy.
Studies have shown that certain people, even when they hear
a fire alarm signal, do not respond to or comprehend the
meaning of the signal. Audible devices, such as horns and
bells, can have different tonal patterns and frequencies. It is
the property owner's responsibility to conduct fire drills and
other training exercises to make people aware of fire alarm
signals and instruct them on the proper reaction to alarm sig-
In rare instances, the sounding of a warning device can cause
temporary or permanent hearing loss.
A life safety system will not operate without any electrical
power. If AC power fails, the system will operate from standby
batteries only for a specified time and only if the batteries have
been properly maintained and replaced regularly.
Equipment used in the system may not be technically compat-
ible with the control panel. It is essential to use only equipment
listed for service with your control panel.
Telephone lines need ed to transmit alarm signals from a prem-
ises to a central monitoring station may be out of service or tem-
porarily disabled. For added protection against telephone line
failure, backup radio transmission systems are recommended.
The most common cause of life safety system malfunction is
inadequate maintenance. To keep the entire life safety system in
excellent working order, ongoing maintenance is required per the
manufacturer's recommendations, and UL and NFPA standards.
At a minimum, the requirements of NFPA 72 shall be followed.
Environments with large amounts of dust, dirt, or high air velocity
require more frequent maintenance. A maintenance agreement
should be arranged through the local manufacturer's representa-
tive. Maintenance should be scheduled as required by National
and/or local fire codes and should be performed by authorized
professional life safety system installers only. Adequate written
records of all inspections should be kept.
Emergency Command Center Manual — P/N LS10001-000FL-E:G 5/3/2016