According to the National Fire Protection Association (NFPA) a fire
department responded to a fire somewhere in the US every 19 seconds in 2002.
In 2002, there were 3,380 civilian fire deaths. In 2002, there were 389,000
reported home fires in the United States, resulting in 2,670 deaths, 13,650
injuries and $5.9 billion in direct property damage.
Are Smoke Detectors Effective?
Only
one-fifth of the home fire deaths from 1989-1998 were caused by fires in
which a smoke alarm was present and operated. The US Consumer Product Safety
Commission (CPSC) recommends consumers place a smoke alarm that meets the
requirements of a professional testing laboratory, such as Underwriters
Laboratories (UL), on each level of multi-story homes outside sleeping
areas, and inside bedrooms. CPSC has worked to strengthen smoke alarm
performance and installation requirements and is now studying audibility to
see if there are ways to make the alarms more effective in waking children
and alerting older people.
The US Fire Administration has the following to say about smoke alarms
“In the event of a fire, a smoke alarm can save your life and those of your
loved ones. They are the single most important means of preventing house and
apartment fire fatalities by providing an early warning signal -- so you and
your family can escape. Smoke alarms are one of the best safety features you
can buy and install to protect yourself, your family and your home.”
FEMA Review Of Deadly Florida House Fire Reflects Importance Of Working
Smoke Alarms
A technical review of a 2001 Florida house fire that killed six people -
five of them children under age seven - has been released by the Federal
Emergency Management Agency (FEMA). According to the review, the lack of a
working smoke alarm allowed the fire to become so intense that rescuing the
victims was impossible. The tragedy is all the worse because it might have
been prevented if there was a working smoke alarm in the home. The local
fire department had an aggressive public education program that included
free smoke alarms and batteries, but demand was not great; interest in the
items increased significantly after the fire. Smoke alarms are inexpensive
and easy to install, and easy to check and keep operational. They are the
closest thing to having a firefighter on duty in your home 24 hours a day. A
copy of the full report can be downloaded by going to:
www.usfa.fema.gov/fire-service/techreports/tr142.shtm.
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Are Fire Systems Required?
Your local fire marshal may require a fire alarm system based upon the
occupancy of the building. The occupancy of a building is determined by how
the building or portion of the building is used. There are different
requirements for schools, offices or other types of uses. Check with your
local fire marshal or your alarm company to determine the requirements for
your application.
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If I Have Smoke Detectors Why Do I Need a Fire System?
There are two major categories of fire alarms: self-contained units, as
exemplified by the single-station residential smoke detector unit
(battery-operated or hard-wired to building electrical power) which produces
an alarm signal at the fixture itself when activated by an integral sensing
device, and building-wide systems, integrated (often zoned) alarms whose
local signals are remotely initiated, either automatically from detectors or
manually from pull stations spread throughout a facility.
Fire detection is often available as part of a complete burglar alarm
system. The smoke/heat detectors may be hardwired back to a control unit
which can be used to activate a number of reporting devices. Wireless
systems are also available.
This type of alarm system has many advantages to protect your life and
property including:
- The ability to summon the Fire Department for immediate action whether
you are at home or away.
- In a fire alarm system all the component are powered from a control
panel that has backup battery power to operate the system in the event of
a power failure.
- If one fire sensor picks up a fire all of the notification devices
activate to make sure that you know a fire has been detected.
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Alarm Initiating Devices and Detectors
Selecting the right detector for the job requires defining the hazard(s)
and level of detection required. Among the variables to be considered are
speed, sensitivity, accuracy, ambient conditions of the device location,
integration with controller and device packaging as well as code
requirements.
A variety of types of detectors can be used to form a complete fire
system including:
- Heat Detectors
- fixed temperatures fusible element
- linear detection/heat sensitive cable
- rate of rise detector
- rate compensation detector
- Smoke Detectors
- ionization
- photoelectric
- high sensitivity air sampling
- Optical Flame Detectors
- ultraviolet (UV)
- infrared (IR)
- combination ultraviolet/infrared (UV/IR)
- multi-spectral
- Manual Stations
- Water flow Switches
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Types of Smoke Detectors
A smoke detector warns of fire when it senses the products of combustion
in the atmosphere. As anyone who has a smoke detector too close to the
kitchen knows, a smoke detector goes off very quickly, even in small amount
of smoke. There are slight differences between the two types of smoke
detectors, but they both operate by detecting the products of fire
combustion.
Some smoke detectors are self contained with a sensor to se
nse
the smoke and a very loud electronic horn to wake people up. Self contained
smoke detectors can run off of a 9-volt battery or 120-volt house current.
Some models run off of house current and change to battery backup if the
house current fails.
Others, known as system detectors are powered by a central source and
connect to a control panel to sound the alarm.
Smoke detectors use two types of technology, photoelectric detectors and
ionization, to sense a fire.
Photoelectric Detectors
Photoelectric smoke detectors use light and how it is reflected to detect
smoke. Normally light is projected into a smoke sensing chamber inside the
detector assembly. The light hits a black background of the chamber and is
absorbed. When enough smoke enters the chamber it reflects the light on to a
sensor inside the chamber. This causes the sensor to indicate an alarm.
Photoelectric detectors are better at sensing smoky fires, such as a
smoldering mattress.
Ionization Detectors
Ionization smoke detectors use a small amount of radiation to detect
smoke. A small amount of electrical current flows form one point to another
inside the smoke chamber within the smoke detector. When smoke enters the
chamber it disrupts the flow of current and generates an alarm.
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What are Heat Detectors
Heat detectors warn of fire when the temperature in the area
around
the smoke detector reaches a certain level. Heat detectors do not notice
smoke. Some studies show that heat detectors may not provide early enough
warning to aid escape from a life-threatening fire. However, a heat detector
could be valuable additional protection in areas such as kitchens and
attics, where smoke detectors are not recommended. They are not recommended
for the use in bedrooms or sleeping areas. There are several types of heat
detectors including:
- Rate-of-rise heat detectors: If the temperature sensed by this
type of detector increases faster than a specified rate, an alarm will be
initiated. A typical rate may be 8.3 degrees Centigrade per minute. In
most of these detectors, when the rate of rise element alone has been
activated, the detector is self-restoring.
- Fixed-temperature heat detectors: If the temperature at the
detector rises to the detector’s rated temperature, an alarm is initiated.
Often, when actuated by the fixed temperature element, the detector is
non-restorable and must be replaced. A typical set temperature might be
57.2 degrees Centigrade.
- Combined rate-of-rise/fixed-temperature heat detectors: Some
heat detectors combine both features, providing warning when the
rate-of-rise and/or the absolute temperature is exceeded.
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What
are Pull Stations?
Pull stations allow a building occupant to signal that a fire has been
observed as they leave a building. Manual pull stations are located
according to specific standards in each of the paths that people normally
use to exit a building.
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Types of Notification Devices
Fire
alarm systems utilize an variety of devices to alert building occupants and
fire authorities within the protected area as
well as outside that an event or fault has occurred. These devices include:
- audible alarms (horns, bells, buzzers, chimes, etc.)
- visual alarms (strobes, etc.)
- remote enunciators
- communications systems
- data display and output devices (CRT's, printers, etc.)
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What Are Visual Alarms?
Visual alarms are flashing lights used as fire alarm signals.
The terms visual alarm signal, visible signal device, and visible
signaling appliance are used relatively interchangeably within the fire
protection community; the National Fire Protection Association (NFPA) calls
them visual notification appliances.
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Why are Visual Alarms Required?
One American in a hundred has a severe hearing
loss; nearly one in ten has a significant loss. A visual alarm provides
persons with hearing loss the same warning delivered to hearing persons by
an audible alarm.
In passing the Americans with Disabilities Act in 1990, Congress
specifically directed the Access Board to provide greater guidance regarding
communications accessibility. Thus the ADA Accessibility
Guidelines (ADAAG) require that where emergency warning systems are
provided in new or altered construction, they must include both audible and
visible alarms that meet certain technical specifications.
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What is a Voice Evacuation System
A voice evacuation System operates in conjunction with the Fire Alarm
Control Panel in a building to provide automatic response to life safety
emergencies.
Automatic evacuation, stay-in-place, or other public
address
messages can be played over speakers located throughout the building and
fire authorities can make announcements as necessary to take command of
evacuation or relocation procedures and emergencies.
Fire Fighter Phones or Warden Stations may be included as required.
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Why Voice Evac.?
Why use a voice evacuation system rather than just a standard audible
horn or bell notification? The Life Safety Code, NFPA 101, was changed in
1983 to require voice systems in assembly occupancies where the occupancy
load is 300 persons or more. This change in the Code suddenly included
structures such as theaters, auditoriums, nightclubs, restaurants and even
churches.
With so many devices making alarm like sounds all around us, people have
become complacent to alarm sounds and signals. Combining a signal with a
voice message, instructing occupants what to do, has been proven to be much
more effective in getting people to a safe area.
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Do I Need A Fire Alarm If I Have Sprinklers?
The US Fire Administration says “Don't Forget the Smoke Alarms
Even though fire sprinklers are effective life safety devices you still
need smoke alarms. Some fires can begin as smoldering fires that produce
smoke and gases but don't generate enough heat to activate the sprinklers.
Smoke alarms are needed to provide warning for these situations.”
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How Many Smoke Detectors Do I Need?
Install smoke alarms on every level of your home, including the basement.
Many fatal fires begin late at night or in the early morning. For extra
safety, install smoke alarms both inside and outside the sleeping area. If
all the bedrooms in your home share a single hallway, place the smoke
detector in the hall outside the rooms. You should have an additional
detector outside every bedroom that doesn't share a common hallway. If you
sleep with the door closed, put another detector inside the bedroom. On
floors without bedrooms, place detectors in or near living areas. A good
place for a smoke detector in a two-story house is at the top of the stairs
since smoke from downstairs will rise along that path.
Also, smoke alarms should be installed on the ceiling or 6 to 8 inches
below the ceiling on side walls. Since smoke and many deadly gases rise,
installing your smoke alarms at the proper level will provide you with the
earliest warning possible. Always follow the manufacturer's installation
instructions.
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How Long Will My Smoke Alarm Last?
About eight-to-ten years, after which it should be replaced. Like most
electrical devices, smoke alarms wear out. You may want to write the
purchase date with a marker on the inside of your unit. That way, you'll
know when to replace it. Always follow the manufacturer's instructions for
replacement.
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