Fire alarm system limitations – Fire-Lite ACM-8RF Control Relay Module User Manual

Page 2

Advertising
background image

LimWarSm.p65 01/10/2000

An automatic fire alarm system–typically made up

of smoke detectors, heat detectors, manual pull

stations, audible warning devices, and a fire alarm

control 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 recommendations of the current

edition of the National Fire Protection Association

Standard 72 (NFPA 72), manufacturer's recommenda-

tions, State and local codes, and the recommenda-

tions contained in the Guide for Proper Use of System

Smoke Detectors, which is made available at no

charge to all installing dealers. 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 guaran-

tee 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 develop-

ing 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 detec-

tors are located.

• Smoke particles may be blown away from detec-

tors 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 limitations. Detectors that have photoelec-

tronic 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, 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 temporary 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

maintained and replaced regularly.

Equipment used in the system may not be

technically compatible with the control. 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 disabled. 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 working order, ongoing

maintenance is required per the manufacturer's

recommendations, and UL and NFPA standards. At a

minimum, the requirements of Chapter 7 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 monthly or as

required by National and/or local fire codes and

should be performed by authorized professional fire

alarm installers only. Adequate written records of all
inspections should be kept.

While a fire alarm system may lower insurance
rates, it is not a substitute for fire insurance!

Fire Alarm System Limitations

Advertising