GENERAL REQUIREMENTS
Commercial fire alarm systems are required as a condition of obtaining a “certificate of occupancy” before a business can open for business.  The “National Fire Alarm Code" (NFPA72) is enforced by the Fire Marshal, otherwise known as the “AHJ” (Authority Having Jurisdiction).  Design plans for the fire alarm must be submitted by a “NICET-certified” individual for the approval by the AHJ, before the work begins.  Depending on the layout of the building, below are descriptions of the devices that will be required, and some that may be required.

FIRE DETECTION DEVICES
Smoke Detectors:  Smoke detectors will almost always be required. What needs to be determined is how many and where they should be placed. Smoke detectors detect particles of smoke in the early stages of fire. They must be installed at listed spacing of 25 feet throughout the building in non-dusty environments. They cannot be located outdoors or in areas that reach temperatures below 32 degrees Fahrenheit.

Heat Detectors:  Heat detectors alert to the presence of heat as opposed to smoke. Heat detectors are specified for areas in which smoke detectors would not perform well, such as cold unheated warehouses, in kitchens near stoves and fryers, or dusty areas.  Although they are not as fast-acting as smoke detectors, they provide stable protection.

SPECIALTY FIRE DETECTION DEVICES
Projected Beam Smoke Detectors:  In high ceiling areas, lobbies, gymnasiums, or large atrium situations, it may not be practical to locate conventional smoke detectors on the ceiling.  For these situations, projected beam smoke detectors can guard large areas by emanating a beam of light to a receiver at the other end.  One projected beam smoke detector can protect a large area that would have required dozens of smoke detectors. They sense “light obscuration” across their field of view to activate.  Total blockage is rejected as being a fire signal, and results in a “trouble signal.”  For example, a forklift operator could stack boxes high enough to obscure the beam.  Trouble signals do not result in a dispatch of fire authorities.

Elevator Recall Smoke Detectors:  Specially designed smoke detectors located outside elevators can be designated to “recall” the elevator to ground level so that no one gets trapped in the elevator during a fire.  Responding firefighters can override elevator control with an override key as they deem appropriate.

Duct Smoke Detectors:  Duct smoke detectors prevent smoke from being transmitted throughout the building via the HVAC ductwork.  Specially designed smoke detectors connected to “air sampling tubes” can detect smoke in heating and air conditioning duct work.  They are usually specified in air ducts that exceed 15,000 CFM (cubic feet per minute of air flow).  Upon activation, they automatically shut down the fan of the heating and air conditioning unit to stop the spread of smoke to other areas.

MANUAL PULL STATIONS
Manual pull stations provide a manual means of signaling the remaining occupants of a building of a fire situation.  They are installed near the exit doors and on all levels of the building.

For schools and gymnasiums, plastic covers with their own built-in sounders may be prescribed by the AHJ as a deterrent to mischievous students.

NOTIFICATION DEVICES
Horn/Strobes:  Horn/Strobes alert the occupants of a building during a fire by producing a distinct audible sound along with a blinking light. Horn/Strobes generate a system-wide building evacuation signal, with an audible 3-pulse temporal pattern sound, and a blinking light for the benefit of the hearing impaired.  The 3-pulse temporal pattern attempts to eliminate any confusion to the occupants of the building that the fire alarm has activated, so that they can exit the building quickly.  The placement must be designed by a “NICET-qualified” individual to fulfill the audibility requirement and proper light dispersion.

Strobe Only in Bathrooms:  The Federal law “Americans with Disabilities Act” (ADA) requires that hearing impaired persons must have adequate notification of fire.  Hence, a strobe only (no horn) is required in bathrooms.

Outdoor Horn/Strobes:  The fire code does not address the need for an outdoor horn/strobe.  The reason is that the fire code addresses the Life-Safety Issue.  If someone is already outside, there is no evacuation notification necessary.  However, the local AHJ may specify an outdoor horn/strobe so that responding firefighters can locate the affected building more quickly, before the flames are visible.

DISPLAY CONSOLE
Display Consoles are located near the front door of the business or the “common lobby”, for the benefit of the responding firefighters in identifying the location of the fire.  The display console must be red in color and must clearly indicate where they should focus their attention.

FIRE ALARM CONTROL PANELS
The fire alarm control panel must be “commercially rated” for the purpose by Underwriters Laboratories (U.L.).  Fire control panels must comply with rigid standards and redundancy of fire alarm communication methods.

The “NICET-certified” individual in charge of the design must also provide battery calculations to provide proper battery standby during power failures.  “Voltage drop” calculations must also be provided to ensure proper wiring size to provide adequate power to all devices connected to the fire alarm system.

SPRINKLER SUPERVISION
Sprinkler Water Flow valves must be monitored for actual water flow.  If a sprinkler head activates, the “water flow valve” will sense the flow of water in the pipe, and the Central Monitoring Station will respond with a dispatch of the fire department.

Sprinkler Supervisory:  A sprinkler supervisory sensor detects the accidental or intentional closing of the water supply or the air pressure drop in dry sprinkler systems. When a sprinkler supervisory signal is received at the Central Monitoring Station, it calls attention to the fact that the sprinkler system is not functioning properly.

Wet Systems:  “Wet” sprinkler systems consist of pressurized water in pipes held back by sprinkler heads.  Water is held back by a piece of solder that melts at 135 degrees Fahrenheit.  If the solder melts, water will squirt through the orifice of the sprinkler head to extinguish the fire.

Dry Systems:    Wet sprinkler systems cannot be used in unheated warehouses because the water would freeze in the pipes below 32 degrees Fahrenheit, causing the pipes to burst. Hence, “dry sprinkler systems” are specified systems that pressurize the pipes with air, holding back the water.  If a sprinkler head “pops”, the air escapes, and the water enters the pipes, permitting the water to flow to extinguish the fire. With a dry sprinkler system, air pressure in the pipes must be supervised.

Fire Inspections:  The fire alarm system must be tested periodically according to the schedule prescribed by the local Authority Having Jurisdiction (AHJ).  Citadel’s technicians are available to test and inspect the fire alarm, clean dust from smoke detectors, correct any fire system violations, and issue the required inspection certificate.

Daily Supervision of Communication:  To ensure that the fire alarm is operating properly, the fire alarm control panel will send a daily communication test to the central monitoring station.  Any irregularities will be reported, generating a service request to fix the problem.