FIRE DETECTION & SUPPRESSION SYSTEMS

And Other Life Safety Requirements for High Rise Buildings

• Fire Alarms

• Automatic Sprinkler, Standpipe, and Fire Pump

• Smoke-proof Tower

• Elevator Recall

FIRE DETECTION SYSTEMS

• HIGH RISE FIRE ALARM SYSTEM
  • A high rise fire alarm system contains a series of panels and components which make up the fire command life safety system. The entire system is supervised and monitored by an Underwriters Laboratory (UL) - listed central station monitoring service that notifies the fire department when water flow is indicated in the sprinkler system or when the heat or smoke detectors are activated.
• SMOKE DETECTORS
  • Are required in:
    • Fan and electrical rooms
    • Return air ducts and plenums
    • Elevator lobbies
    • Corridors on each floor
    • In residential dwelling units within 15 feet of the entrance to all sleeping rooms
• HEAT DETECTORS
  • Are required in:
    • Storage rooms
    • Boiler rooms
    • Furnace rooms
• VOICE COMMUNICATION SYSTEM
  • A two-way voice communication system is required for firefighters’ use to communicate with the incident commander in the event of a fire or emergency.  Firefighter phones are installed on every fifth floor throughout the building’s stairwells.
  • A speaker is required between the fire command panel and the following locations:
    • Elevators and elevator lobbies
    • All required stairwells, one (1) speaker on every fifth floor
    • Office areas exceeding five hundred (500) square feet
    • In corridors, at intervals of at least 75 feet and at the exit stair doors.
• STAIRWELL DOOR UNLOCKING DEVICE
  • All stairwell doors which are locked from the stairwell side are electrically controlled and automatically unlocked from a switch at the fire command panel.  The signal is activated by a switching device at the panel.
• MECHANICAL VENTILATION
  • Where required, the building’s mechanical ventilation system is controlled by the life safety system and also by the activation of the smoke detectors installed within the building’s ductwork and air plenums. This will shut down the ventilation system to prevent the spread of smoke.

FIRE SUPPRESSION SYSTEMS

• AUTOMATIC SPRINKLER SYSTEM
  • An automatic sprinkler system is a system of water pipes, discharge nozzles and control valves designed to activate during a fire to automatically discharge enough water to control or extinguish a fire.
  • Sprinkler systems have an extremely high degree of reliability but despite this high degree of reliability, sprinklers can fail to control or extinguish a fire because of the following factors:
    • closed valves
    • frozen water supplies
    • inadequate water supply
    • obstructed sprinkler discharge
    • damaged sprinkler heads
  • In order for a sprinkler system to function properly, it must be designed, installed and maintained properly.  Water is supplied to the sprinkler system by the suppression system’s fire pump and is augmented by the Siamese (fire department) connection at street level. 
  • Typically, for normal applications, wet and dry sprinkler systems are installed.
    • Wet pipe system: Automatic sprinkler system in which the pipes are constantly filled with water under pressure (See illustration II-A (1) in Reference Guide.)  This type of system is installed in heated buildings and where freezing temperatures are not an issue.
    • Dry pipe system: Fire protection sprinkler system that has air in its piping instead of water under pressure.  Dry systems are installed in areas subject to freezing (See illustration II-A (2) in Reference Guide)
• STANDPIPE SYSTEM
  • Standpipe systems are fixed piping systems with equipment that provide a means to transport water to designated areas of a building where hoses can be deployed for firefighting.  As with the sprinkler system, water is supplied to the standpipe system by the suppressions system’s fire pump and is augmented by the Siamese (fire department) connection at street level.  This connection is made by fire department pumpers.  The standpipe system runs the total height of the stairwell.  Standpipe outlets can also be found in different locations throughout the building, where required.  These systems have 2½ inch threaded port outlets which firefighters use to connect fire hoses to extinguish fires on the upper floors of high rise buildings. Some high rise buildings are required to have 1½ inch hose lines in addition to the 2½ inch port outlets (See illustration II-B-(1) in Reference Guide.) Buildings over 275 feet in height are required to have a two-zone system (See illustration II-B-(2) in Reference Guide).  Sprinkler and standpipe control valves are usually located in the basement.  This is the lifeline of the fire protection system. A sprinkler or standpipe that is out of service can give a false sense of security to the occupants of a high rise building. Both should be in full operation. Building management is required to give prior notice to the fire department in the event of any sprinkler or standpipe repairs or emergency shutdown.
• FIRE PUMP
  • Whenever a building’s existing water supply, whether it is a public main or other sources, is insufficient to meet the demands of its fire protection system, a fire pump is installed.  Fire pumps are used to provide or enhance the water supply pressure available from the public water mains.  Fire pumps are an important component of the fire protection system.  The Chicago Fire Codes require that these pumps be tested annually and that these tests be witnessed by the Chicago Fire Department.  Fire pumps must perform to their rated gallons per minute and pressure to ensure proper and adequate flow of water supply.  As with sprinklers and standpipe systems, building management is required to give prior notice to the fire department in the event of any fire pump repairs or emergency shutdown.
• SMOKE-PROOF TOWERS
  • A smoke-proof tower is an enclosed stairwell designed to limit the penetration of smoke, heat and toxic gases, providing a safer atmosphere for occupant evacuation in the event of a fire.  A smoke-proof tower may be used in lieu of any required interior stairwell.  At least one smoke-proof tower is required in every high rise building that exceeds 264 feet in height.  These towers are constructed with a three (3) hour fire-resistive rating.  If more than one (1) smoke-proof tower is provided, this rating can be reduced to two (2) hours (See illustration III-A in Reference Guide).
• ELEVATOR RECALL
  • Elevator emergency recall is a system which is programmed into the elevator to send it non-stop to the main floor so the fire department can take control of the elevator in a fire situation or emergency.  This control of the elevator is called fireman service mode.  When elevators are in the fireman service mode, they cannot be used by anyone but firefighters.  Keys used by firefighters to recall the elevators are found in the fireman’s recall box, installed in a conspicuous location on the main floor of the elevator lobby.  The size of the box, the construction and the type of lock must be approved by the Chicago Fire Department.
• PORTABLE FIRE EXTINGUISHERS
  • Portable fire extinguishers can save lives and property by putting out a small fire or suppressing it until the fire department arrives.  However, portable extinguishers have limitations.  They are not designed to fight large or fast-spreading fires.  Most portable extinguishers have a short-range (6-10 feet) and completely discharge in a very short time (8-10 seconds).  As a general rule, firefighting should be left to the professionals. The Chicago Fire Department recommends that they are called in the event of any fire. 
  • Modern fire extinguishers can put out small fires, but using a portable fire extinguisher is a good idea only under certain conditions.  All fires are unpredictable and should be approached with caution.
  • No step-by-step list can take the place of experience and training.  Anyone who uses a fire extinguisher should be trained and familiar with them.
  • With that in mind, before you consider fighting a small fire, you should know the following:
    • Make sure the Fire Department is notified.  As soon as you know there is a fire call 9-1-1.
    • Never fight a fire unless you are sure you have the proper type and size of extinguisher and that you know how to use it.
    • Begin fighting the fire from a safe distance.
    • Never let the fire get between you and your exit.
    • Use the buddy system. Always work in pairs.
    • Even if you extinguish the fire, the area should be inspected by the fire department.              
  • The extinguisher must be rated for the type of fire you are fighting.
  • Extinguishers are designed to fight specific classes of fires. What type of extinguisher to use depends on what is burning.
  • The extinguisher must be large enough to put out the fire.
  • Extinguishers come in various sizes. Larger models can handle larger fires.
  • The extinguisher must be within easy reach.
  • Never move through fire to get your extinguisher.
  • The extinguisher must be fully charged.
  • If an extinguisher is not fully charged it will not do its job.
  • The operator must be trained to use the extinguisher.
  • During a fire is not the time to learn to use an extinguisher. You should be familiar with each type of extinguisher available to you. 
  • When operating portable extinguishers, personal safety and the safety of others are the most important factors in deciding to fight a small fire.
  • Before fighting a fire be sure of the following:
    • Everyone has left or is leaving the building/area and the fire department has been called.
    • The fire is confined to a small area.
    • There is an unobstructed exit available. Don’t let the fire get between you and your exit.
    • Stay low because the room will rapidly fill with smoke.
    • If in doubt, leave the area immediately.
    • Close off the area to slow the spread of the fire.
  • It is essential that the type of extinguisher you use is appropriate for the type of fire you are fighting.
  • The A, B, and C classification describe the fire’s fuel, and what is burning.
    • Class A fires involve “ordinary combustibles” - wood, paper, cloth, rubbish, rubber, and many plastics.
    • Class B fires involve flammable liquids - oil, greases, tar, oil based paint, lacquers, flammable gasses, and some plastics.
    • Class C fires involve “energized” electrical equipment - appliances, televisions, radios, computer equipment, wiring, and circuit breakers or fuse boxes.
  • Class A, pressurized water extinguishers, are common in retail and office settings. Water is stored in the extinguisher cylinder and is expelled through a short hose. Water extinguishers Class A fires by cooling the fuel below its kindling temperature.
  • Class B&C, carbon dioxide extinguishers, are common where electrical equipment is prevalent. When activated, carbon dioxide is expelled under pressure through a horn at the end of a short hose. The fire is extinguished by reducing the amount of oxygen in the air around the fire.
  • Class A, B & C, multipurpose dry-chemical extinguishers, are common in office and home settings. Dry-chemical (ammonium phosphate) is stored in the cylinder and expelled through a nozzle or short hose. The fire is extinguished by interrupting the chain reaction that keeps the fire burning.

There are four basic steps to operating a fire extinguisher.

An easy way to remember the procedure is to think of the word “PASS”

• PULL THE PIN
  • Holding the extinguisher with the nozzle pointing away from you, pull the pin, which is located below the trigger.
• AIM LOW
  • Standing 6-8 feet away from the fire, point the nozzle at the base of the fire.  Always hold the extinguisher vertically.  Never hold it horizontally or at an angle.
• SQUEEZE THE TRIGGER
  • Squeeze the trigger slowly and evenly.  This will expel the extinguishing agent.
• SWEEP FROM SIDE TO SIDE
  • As the agent is being expelled, sweep the nozzle from side to side.  As the fire begins to go out, move closer to the fire and continue the sweeping motion until the fire is extinguished.  If the fire does not diminish or it grows, get out of the building.  Close any doors in order to contain the fire to the immediate area.

Fires require fuel, heat, oxygen and a molecular chain reaction.  Once a fire has started, it will continue to burn because of the reactions created between these four components.  Fire experts call this model the “Fire Tetrahedron”.   Removing any one of these components will cause the fire to be extinguished.

• Fire extinguishers put out fires by combinations of three basic methods:
  • Cooling the fuel below the temperature at which it will burn.
  • Cutting off the oxygen supply.
  • Interrupting the chemical reactions that keep the fire going.