2 Johnson Controls Web Server-3 Installation and Operation Manual - P/N: 53550:Rev: A1 1/12/10
Fire Alarm System Limitations
While a fire alarm system may lower insurance rates, it is not a substitute for fire insurance!
An automatic fire alarm system—typically made up of smoke detec-
tors, heat detectors, manual pull stations, audible warning devices,
and a fire alarm control panel 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.
The Manufacturer recommends that smoke and/or heat detectors be
located throughout a protected premise following the recommenda-
tions 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. These documents can be found at
http://www.systemsensor.com/html/applicat.html.
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 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, or chimneys
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.
• 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 limita-
tions. Detectors that have photo-electronic sensing chambers tend to
detect smoldering fires better than flaming fires, which have little visi-
ble 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 detec-
tor 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 escap-
ing 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 connec-
tion of alarm transmission wiring, communications, signaling, and/or
power. If detectors are not so located, a developing fire may damage
the alarm system, crippling its ability to report a fire.
Audible warning devices such as bells 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:
• 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 or comprehend the meaning of the signal.
It is the property owner's responsibility to conduct fire drills and other
training exercise 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 tempo-
rary or permanent hearing loss.
A fire alarm 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 main-
tained 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.
Telephone lines needed to transmit alarm signals from a premise to a
central monitoring station may be out of service or temporarily dis-
abled. For added protection against telephone line failure, backup
radio transmission systems are recommended.
The most common cause of fire alarm malfunction is inadequate
maintenance. To keep the entire fire alarm system in excellent work-
ing 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 mainte-
nance. A maintenance agreement should be arranged through the
local manufacturer's representative. Maintenance should be sched-
uled monthly or as required by National and/or local fire codes and
should be performed by authorized professional fire alarm installers
