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64 Cards in this Set
- Front
- Back
• Fire prevention and building codes
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IFC chapter 903, IBC chapter 903, NFPA 13 and 72 for requirements
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• Fire sprinkler systems are effective in |
controlling fires 96% of the time
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• A fire detection system recognizes when a fire is occurring and activates the fire alarm system(4) |
o Alerts occupants o May alert fire department o May automatically activate fire suppression systems o Secondary purpose is to conserve property |
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Residential Fire Alarm Systems |
• Single station smoke alarm most common types of residential alarm system • Includes both a smoke detection device and an audible alarm • Smoke alarms can be battery powered or hard wired to a 110 volt electrical system • Up to date codes require new homes to have a smoke alarm in every bedroom and on every floor level • Many home fire alarm systems are part of security systems |
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Ionization VS Photoelectric Smoke Detectors |
• Ionization detectors are triggered by the invisible products of combustion • Photoelectric detectors are triggered by the visible products of combustion |
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• Three basic components in a fire alarm system: |
o Alarm initiation device o Alarm notification device o Control panel |
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Fire Alarm System Control Panels |
• Serves as the brain of the system • Manages and monitors the proper operation of the system • Can indicate the source of an alarm • Also manages primary power supply and provides backup power supply for the system • May perform additional functions, and may interface with other systems and facilities • Vary greatly depending on age of system and manufacturer • Used to silence the alarm and reset the system • Many buildings have an additional display panel, called a remote annunciator in a separate location near the main entry way or lobby is a good location for annunciator panels • A battery in the fire alarm control panel will automatically activate when the external power is interrupted |
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Alarm Initiating Devices |
• Components that activate a fire alarm system • Manual initiation devices require human activation • Automatic devices function without human intervention |
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Manual Initiation Devices |
• Designed so that building occupants can activate the fire alarm system • Primary manual initiation device is the manual fire alarm box, or manual pull station • Once activated should stay in the activated position until it is reset |
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Automatic Initiating Devices |
• Designed to function without human intervention • Can use several different types of detectors o Some detectors activated by smoke or by invisible products of combustion o Others react to heat, light produced by an open flame, or specific gases |
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Smoke Detectors |
• Designed to sense the presence of smoke • Commonly found in school, hospital, business, and commercial occupancies with fire alarm systems • Most common are ionization and photoelectric detectors |
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Heat Detectors |
• Can provide property protection, but cannot provide reliable life safety protection • Generally used in situations where smoke alarms cannot be used • Often installed in unheated areas • Generally very reliable and less prone to false alarms that smoke detectors |
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Fixed Temperature Heat Detectors |
• Designed to operate at a preset temperature • Usually use a metal alloy that will melt at the preset temperature |
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Rate of Rise Detectors |
• Will activate if the temperature of the surrounding air rises more than a set amount in a given period of time • Most rate of rise heat detectors are self monitoring • Generally respond faster to most fires than fixed temperature heat detectors |
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Line Heat Detectors |
• Use wires or a sealed tube to sense heat • One type has two wires inside, separated by an insulating material • Another types measures changes in the electrical resistance of a single wire as it heats up • The tube type line heat detector has a sealed metal tube filled with air or a nonflammable gas |
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Flame Detectors |
• Specialized devices that detect the electromagnetic light waves produced by a flame (infrared or ultraviolet) • Typically found in places where early detection and rapid reaction to a fire is critical • Complicated and expensive • Arc welding can cause accidental activation of ultraviolet flame detectors |
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Gas Detectors |
• Calibrated to detect the presence of a specific gas • Need regular calibration • Usually found only in specific commercial or industrial applications • Gases released by a fire that a detector would sense are carbon monoxide, carbon dioxide, hydrogen chloride, hydrogen cyanide, hydrogen fluoride, and hydrogen sulfide |
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Air Sampling Devices |
• Continuously capture air samples and measure the concentrations of specific gases or products of combustion |
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Alarm Initiation by Fire Suppression Systems |
• System alerts building occupants and the fire department to a possible fire • Water flow alarm ensures that someone is aware water is flowing from a sprinkler head or when standpipe valve is opened |
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• Malicious false alarms |
o Caused by individuals who deliberately activate a fire alarm when there is no fire |
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• Unwanted alarms |
o Occur when an alarm system is activated by a condition that is not really an emergency |
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• Nuisance alarms |
o Caused by improper functioning of an alarm system or one of its components |
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Alarm Notification Appliances |
• Produce an audible signal when fire alarm is activated • Some signals play a recorded announcement in conjunction with the temporal 3 pattern • Many new systems incorporate visual notification devices |
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Other Fire Alarm Functions |
• May also control other building functions, such as air handling systems, fire doors, and elevators • Responding fire personnel must understand which building functions are being controlled by the fire alarm |
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Fire Alarm Annunciation Systems |
• Almost all alarm systems are now zoned to some extent • In a coded system, zone is identified not only at alarm control panel but also through audio notification device • Systems can be broken down into four categories: non-coded alarm, zoned non-coded alarm, zoned coded alarm, and master-coded alarm |
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Non-Coded Alarm System |
• Control panel has no information indicating where in the building the fire alarm was activated • Typically sounds a bell or horn • Fire department personnel must search the entire building to find which initiation device was activated |
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Zoned Non-Coded Alarm System |
• Most common type of system, particularly in newer buildings • Building divided into multiple zones, often by floor or by wing • Alarm control panel indicates in which zone the activated device is located |
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Zone Coded Alarm |
• In addition to having all the features of a zoned alarm system, also indicated which zone has been activated over the announcement system • Hospitals often use this type of system |
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Master-Coded Alarm |
• Audible notification devices for fire alarms also are used for other purposes • Most of these systems have been replaced by modern speaker systems that use the temporal 3 pattern fire alarm signal and have public address capabilities |
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• Local alarm system |
o Does not notify the fire department o The alarm sounds only in the building to notify the occupants |
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• Remote station system |
o Sends signal directly to fire department or to another monitoring location via a telephone line or a radio signal |
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• Auxiliary system |
o Building’s fire alarm system is tied into a master alarm box located outside |
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• Proprietary system |
o Building’s alarms connected directly to monitoring site owned and operated by building owner |
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• Central station |
o Third party off site monitoring facility that monitors multiple alarm systems o An activated alarm transmits a signal to the central station by telephone or radio o Personnel at the central station then notify the appropriate fire department of the fire alarm |
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Fire Suppression Systems |
• Include automatic sprinkler systems, standpipe systems, and specialized extinguishing systems such as dry chemical systems • Understanding how these systems work is important because they can affect fire behavior |
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Automatic Sprinkler Systems |
• One of the major advantages of a sprinkler system is that is can act a fire detection system and a fire suppression system • Closed valves inadequate water supply, blocked heads, fire load changes, partial protection and poor maintenance are reasons systems fail • Sprinkler system define as- a system of pipes, valves, water, and heads, which operate automatically to control or extinguish fire, initiate an alarm, save lives and property |
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• Four major components: auto sprinkler systems |
o Automatic sprinkler heads o Piping o Control valves o A water supply, which may or may not include a fire pump |
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Automatic Sprinkler Heads |
• The working ends of a sprinkler system • Composed of: o A body, which includes the orifice o A release mechanism that holds a cap in place over the orifice o A deflector that directs the water in a spray pattern |
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Fusible Link Sprinkler Heads |
• Use a metal alloy, such as solder that melts at a specific temperature o Alloy links two other pieces of metal that keep the cap in place o When designated operating temperature is reached, solder melts and the link breaks, releasing the cap |
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Frangible Bulb Sprinkler Heads |
• Use a glass bulb filled with glycerin or alcohol to hold the cap in place • As bulb is heated liquid absorbs the air bubble and expands until it breaks the glass, releasing the cap |
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Chemical Pellet Sprinkler Heads |
• Use a plunger mechanism and a small pellet to hold the cap in place • Pellet will liquefy at a preset temperature • When pellet melts, liquid compresses the plunger, releasing the cap and allowing water to flow |
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Special Sprinkler Heads |
• Designed for special applications o covering large areas o discharging the water in extra large droplets • ESFR sprinkler heads have improved heat collectors to speed up response and ensure rapid release |
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Deluge Sprinkler Heads |
• Easily identifiable, because they have no cap or release mechanism • Orifice is always open • Only used in deluge sprinkler systems • Deluge systems are designed to protect extra hazardous occupancies |
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Temperature Ratings |
• Typical rating for sprinkler heads in a light hazard occupancy would be 165 degrees F • Rating should be stamped on the body of the sprinkler head • Temperature rating must match the anticipated ambient air temperatures • Spare heads that match those used in the system should always be available on site • Uncolored or black sprinkler heads have an operating temperature 135-170 degrees F |
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Sprinkler Piping |
• Network of pipes that delivers water to sprinkler heads • Includes main water supply lines, risers, feeder lines, and branch lines • Usually made of steel • Plastic pipes sometimes used in residential systems |
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Valves |
• A sprinkler system includes several different valves such as: o Main water supply control valve o Alarm valve o Other, smaller valves used for testing and service o All of the valves play a critical role in the design and function of the system |
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Water Supplies |
• Water may come from municipal water system, on site storage tanks, or static water sources • Water supply must be able to handle demand of the sprinkler system, as well as the needs of the fire department • Preferred water source for a sprinkler system is a municipal water supply • Retard chambers can be added to fire sprinkler system risers to help reduce false alarms due to momentary water surges |
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Fire Pumps |
• Used when the water comes from a static source • May also be used to boost the pressure in some sprinkler systems, particularly for tall buildings |
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FDC |
• Allows the department’s engine to pump water into the sprinkler system • Used as either a supplement or the main source of water |
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Water Flow Alarms |
• Most systems incorporate a mechanical flow alarm called a water motor gong • When system is activated and main alarm valve opens, water is fed through a pipe to a water powered gong located outside the building |
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• Wet sprinkler systems |
o Most common and the lease expensive types of automatic sprinkler system o Piping always filled with water o As sprinkler head activates, water is immediately discharged onto the fire o Major drawback: cannot be used in areas where temperatures drop below freezing o Will also flow water if a sprinkler head is accidentally opened or a leak occurs in the piping |
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• Dry sprinkler systems |
o Operate much like wet sprinkler systems, except that the pipes are filled with pressurized air instead of water, used in areas subject to freezing o A dry pipe valve keeps water from entering the pipes until the air pressure is released |
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• Pre-action sprinkler systems |
o Similar to a dry sprinkler system with on key difference o A secondary device must be activated before water is released into the sprinkler piping o When the system is filled with water, it functions as a wet sprinkler system |
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• Deluge sprinkler systems |
o Water flows from all of the sprinkler heads as soon as the system is activated o Does not have closed heads that open individually at the activation temperature; all of the heads are always open |
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Shutting Down Sprinkler Systems |
• Order to shut down sprinkler system should come only from the IC • In most cases, system can be shut down by closing main control valves such as one of the following: OS&Y, PIV, WPIV, or PIVA • Placing a wooden wedge or a commercial sprinkler stop into the sprinkler head can quickly stop the flow of water o This will not work on all types of heads |
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Residential Sprinkler Systems |
• Relatively new, but many homes now being built include them • Typically use smaller piping and sprinkler heads with smaller orifices and less water discharges |
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Standpipe Systems |
• Network of pipes and outlets for fire hoses built into a structure to provide water for firefighting purposes • Actual water flow depends on water supply, as well as on the condition of the piping system and fire pumps • Flow restricted devices or pressure reducing valves often installed at outlets to limit pressure and flow |
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Water Supplies |
• Wet standpipe systems in modern buildings are connected to a public water supply with an electric or diesel fire pump to provide additional pressure • Most dry standpipe systems do not have a permanent connection to a water supply, so the FDC must be used to pump water into the system |
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Specialized Extinguishing Systems |
• Specialized extinguishing systems are often used in areas where water would not be an acceptable extinguishing agent |
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Dry Chemical Extinguishing Systems |
• Use the same types of finely powdered agents as dry chemical fire extinguishers • Agent kept in self pressurized tanks or in tanks with an external cartridge of carbon dioxide or nitrogen that provides pressure when the system is activated |
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Wet Chemical Extinguishing Systems |
• Used in most new commercial kitchens • Use a proprietary liquid extinguishing agent • Much more effective on vegetable oils than the dry chemicals used in older kitchen systems |
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Initiation Devices |
• Fusible links are placed above the target hazard to activate extinguishing systems • Manual discharge pull station is also provided so that workers can activate the system if they discover a fire |
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Clean Agent Extinguishing Systems |
• Often installed in areas where computers or sensitive electronic equipment are used, or where valuable documents are stored • Nonconductive and leave no residue • Halogenated agents or carbon dioxide are generally used • Operate by discharging a gaseous agent into the atmosphere at a concentration that will extinguish a fire • If there is a fire, the clean agent system should be completely discharged before firefighters arrive • Should be tied to building’s fire alarm system and indicated as a zone on the control panel o Alerts firefighters they are responding to a situation where a clean agent has discharged |
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Carbon Dioxide Extinguishing Systems |
• Designed to protect a single room or a series of rooms • Should be connected to the building’s fire alarm system |