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
notification 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 communication, and
other various interoperable communication methods—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 NationalFire 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 ManagementAgency (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 closeddoors. Smoke detectors also may notsense a fire
on another level or floor of a building. A second-floor detector, for
example, may not sense a first-floor or basement fire.
Particles of combustion or “smoke” from a developing fire may not
reach the sensing chambers of smoke detectors because:
• Barriers such as closed or partially closed doors, walls, chimneys,
even wet or humid areas may inhibit particle or smoke flow.
• 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 reaching the
detector.
The amount of “smoke” present may be insufficient to alarm smoke
detectors. Smoke detectors are designed to alarm at various levels of
smoke density. If such density levels are not created 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 chambers
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 warning 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 materials, etc.).
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 detectors may be
subject to reduced sensitivity over time. For this reason, 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 developing fire may
damage the alarm system, compromising its ability 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 that:
• 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 intelligibility
requirements as defined by NFPA, local codes, andAuthorities
Having Jurisdiction (AHJ).
• Language and instructional requirements must be clearly dissemi-
nated on any local displays.
• Strobes can, under certain circumstances, cause seizures in peo-
ple 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 dif-
ferent 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 signals.
• 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 compatible
with the control panel. It is essential to use only equipment listed for
service with your control panel.
Alarm Signaling Communications:
•IP connections rely on available bandwidth, which could be lim-
ited if the network is shared by multiple users or if ISP policies
impose restrictions on the amount of data transmitted. Service
packages must be carefully chosen to ensure that alarm signals
will always have available bandwidth. Outages by the ISP for
maintenance and upgrades may also inhibit alarm signals. For
added protection, a backup cellular connection is recommended.
•Cellular connections rely on a strong signal. Signal strength can
be adversely affected by the network coverage of the cellular car-
rier, objects and structural barriers at the installation location. Uti-
lize a cellular carrier that has reliable network coverage where the
alarm system is installed. For added protection, utilize an external
antenna to boost the signal.
•Telephone lines needed to transmit alarm signals from a premise
to a central monitoring station may be out of service or temporarily
disabled. For added protection against telephone line failure,
backup alarm signaling connections 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 representative.
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. Limit-F-2020
