Chapter 16 II
Chapter 16 II
Chapter 16 II
5th Edition
student shall be able to operate different types of fire detection, alarm, and suppression systems and identify the different types of alarm and auxiliary systems following the policies and procedures set forth by the authority having jurisdiction (AHJ).
Firefighter II 161
Specific Objectives
1. Describe types of heat detectors. 2. Describe types of smoke detectors/alarms. 3. Explain how flame detectors and firegas detectors operate.
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Firefighter II 162
Specific Objectives
4. Discuss combination detectors and indicating devices. 5. Describe types of automatic alarm systems. 6. Discuss supervising fire alarm systems and auxiliary services.
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Firefighter II 163
Specific Objectives
7. Describe the operation of an automatic fire sprinkler system. 8. Discuss water supply for sprinkler systems. 9. Describe major applications of sprinkler systems.
Firefighter II 164
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Firefighter II 166
Firefighter II 167
temperature in room will increase faster from fire than from normal atmospheric heating Designed to initiate signal when rise in temperature exceeds 12 to 15F (-11C to -9C) in one minute
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Firefighter II 168
far below that required for initiating fixed-temperature device Reliable, not subject to false activations Pneumatic rate-of-rise spot detector
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Firefighter II 169
Firefighter II 1610
Smoke Detectors
transmit signal to another device that sounds alarm Respond to smoke or other products of combustion Preferred over heat detectors
Firefighter II 1611
Smoke Alarms
Capable of
Detecting presence of smoke Sounding an alarm
Firefighter II 1612
produced during combustion Use a tiny amount of radioactive material to ionize air molecules as they enter chamber within detector
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Firefighter II 1614
satisfactorily to most fires Respond faster to flaming fires than smoldering ones
Firefighter II 1615
Firefighter II 1616
Flame Detectors
Types Among most sensitive detectors used to
detect fires Prone to being activated by nonfire conditions
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Firefighter II 1617
Flame Detectors
Usually positioned in areas
where other light sources unlikely Positioned to have unobstructed view of protected area
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Firefighter II 1618
Flame Detectors
Some single-band IR detectors sensitive
to sunlight, should be installed in fully enclosed areas UV detectors virtually insensitive to sunlight, can be used in areas not suitable for IR detectors
Firefighter II 1619
Fire-Gas Detectors
Monitor levels of carbon dioxide, carbon
monoxide because these are only chemicals released from all fires Initiate alarm signal faster than heat detector but not as quickly as smoke detector
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Firefighter II 1620
Fire-Gas Detectors
Can be more discriminating than other
types Can be designed to be sensitive only to specific gases
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Firefighter II 1621
Fire-Gas Detectors
to sense gas, transmit signal to initiate alarm Not used as frequently as other types
Firefighter II 1622
Combination Detectors
Various combinations of previously described means of detection may be used in single device
Firefighter II 1623
Indicating Devices
Some produce loud signal
to attract attention in high-noise areas Some generate electronic tone audible in almost any type of environment Some employ bells, horns, chimes
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Firefighter II 1624
Indicating Devices
Others use speakers that
broadcast prerecorded evacuation instructions May include visual alarm indicators to accommodate special circumstances/populations
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Firefighter II 1625
Indicating Devices
May include strobe
indicators Must meet requirements of Americans with Disabilities Act in areas where there may be people with hearing impairments
Firefighter II 1626
summon organized assistance Produce automatic response upon activation of local alarm May be installed to complement wetpipe or dry-pipe sprinkler systems
Firefighter II 1627
Auxiliary Systems
Local energy systems Shunt systems Parallel telephone
systems
Firefighter II 1628
connected to fire department telecommunication center directly/through answering service by some means other than municipal fire alarm box system
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Firefighter II 1629
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Firefighter II 1630
signal Must have ability to transmit trouble signal to fire alarm center when system impaired
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Firefighter II 1631
evacuation is not desired action in fire May be monitored by entity besides fire department
Firefighter II 1632
Proprietary Systems
Used to protect
large commercial, industrial buildings, high-rise buildings, groups of commonly owned buildings in single location
Firefighter II 1633
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Proprietary Systems
Each building/area has own system
wired into a common receiving point somewhere on facility The receiving station Capabilities
Firefighter II 1634
instead of having alarm-receiving point monitored by occupants representative on protected premises, receiving point is at off-site, contracted service point called a central station
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Firefighter II 1635
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Firefighter II 1636
Firefighter II 1638
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Firefighter II 1639
Firefighter II 1640
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Firefighter II 1641
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Firefighter II 1642
Firefighter II 1643
Firefighter II 1645
Sprinklers
Discharge water after release of cap
or plug activated by some heatresponsive element such as fusible link
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Firefighter II 1646
Sprinklers
Identified by temperature at which
designed to operate, either by colorcoding, using different colored liquid, stamping temperature on sprinkler
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Firefighter II 1647
Sprinklers
Fusible link
Frangible bulb
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Firefighter II 1648
Sprinklers
Chemical pellet
Firefighter II 1649
Sprinkler Position
Pendant
Upright
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Firefighter II 1650
Sprinkler Position
Sidewall Special-purpose
Firefighter II 1651
Sprinkler Storage
Storage cabinet to house spare
sprinklers, a sprinkler wrench usually installed near sprinkler rise, main shut-off valve Cabinets hold a minimum of six sprinklers and sprinkler wrench in accordance with NFPA 13 and 13D
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Firefighter II 1652
Sprinkler Storage
In many jurisdictions, job of changing
sprinklers must be performed by representatives of buildings occupants qualified to perform work on sprinkler systems
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Firefighter II 1653
Sprinkler Storage
In other jurisdictions, firefighters
Firefighter II 1654
Water Supply
Minimum water supply has to deliver
required volume of water to highest sprinkler in building at residual pressure of 15 psi (105 kPa) Minimum flow depends on hazard to be protected, occupancy, building contents
Firefighter II 1655
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Water Supply
In most cases, water supply for
sprinkler systems designed to supply only fraction of sprinklers actually installed on system If large fire occurs/pipe breaks, sprinkler system will need outside source of water and pressure
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Firefighter II 1656
Water Supply
Sprinkler FDCs should be supplied with
water from pumpers that have capacity of at least 1,000 gpm (4 000 L/min) or greater; minimum of two 2-inch (65 mm) or larger hoses should be attached to the FDC
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Firefighter II 1657
Water Supply
After water flows through FDC into
system, passes through check valve Proper direction of water flow through check valve usually indicated by arrow on valve or appearance of valve casing
Firefighter II 1658
Water Supply
Departmental preincident plans may
Firefighter II 1659
Wet-Pipe Systems
Used in locations where
temperatures below 40F (4C) not expected Simplest type of automatic fire sprinkler system
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Firefighter II 1660
Wet-Pipe Systems
Generally require little maintenance Contain water under pressure at all
times Connected to public/private water supply so fused sprinkler immediately discharges water spray, actuates alarm
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Firefighter II 1661
Wet-Pipe Systems
Usually equipped with alarm check
valve installed in main riser adjacent to where feed main enters building Newer versions may have a backflow prevention check valve and electronic flow alarm.
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Firefighter II 1662
Wet-Pipe Systems
May be equipped with retarding device
as part of alarm check valve
Firefighter II 1663
Dry-Pipe Systems
Used in locations
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Firefighter II 1664
Dry-Pipe Systems
Have pitched (sloped) pipes to help
drain water in system back toward main drain Replace water in sprinkler piping with air under pressure
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Firefighter II 1665
Dry-Pipe Systems
Designed so small amount of air
pressure above dry-pipe valve will hold back much greater water pressure on water supply side of dry-pipe valve Equipped with electric or hydraulic alarm-signaling equipment
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Firefighter II 1666
Dry-Pipe Systems
Larger systems may have several-
Firefighter II 1667
Preaction Systems
Dry systems that employ deluge-type
valve, fire detection device, closed sprinklers Used when especially important to prevent water damage, even if pipes broken
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Firefighter II 1668
Preaction Systems
Will not discharge water into sprinkler
piping except in response to smoke- or heat-detection system actuation Sound alarm to give warning before opening of sprinklers
Firefighter II 1669
Deluge Systems
Similar to dry-pipe system in no water
in distribution piping before system activation Differ from dry-pipe systems in sprinklers have no fusible links, do not function as fire detection devices
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Firefighter II 1670
Deluge Systems
Designed to quickly supply large volume
of water to protected area Sometimes used to discharge foam/other extinguishing agents in occupancies containing flammable liquids, other volatile fuels
Firefighter II 1671
Residential Systems
Installed in one- and two-family
dwellings Designed to give occupants of dwelling chance to escape, prevent total involvement in room of origin Employ quick-response sprinklers
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Firefighter II 1672
Residential Systems
Use several types of piping systems Must have pressure gauge, flow
detector, means for draining and testing system Can be either connected directly to public water supply or to dwellings domestic water system
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Firefighter II 1673
Residential Systems
Require control valve to turn off water
to sprinkler system and to domestic water system if connected; if sprinkler system supplied separately from domestic water system, sprinkler control valve must be supervised in open position
Firefighter II 1674
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Residential Systems
Operate in same manner as other wet-
pipe/dry-pipe systems May be equipped with fire department connection (FDC); FDC may be 1-inch (38 mm) connection
Firefighter II 1675
Summary
Many of the buildings to which
firefighters are called for emergency operations are protected partially or fully by automatic fire detection and/or suppression systems.
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Firefighter II 1676
Summary
Firefighters need to familiarize
themselves with the types of systems installed in their area of responsibility. They should also learn the locations of these systems as well as the capabilities and limitations of each type of system.
Firefighter II 1677
Review Questions
1. How does a photoelectric smoke detector work? 2. How do flame detectors work? 3. Describe the three basic types of auxiliary automatic alarm systems.
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Firefighter II 1678
Review Questions
4. What is a proprietary automatic alarm system? 5. Describe commonly used release mechanisms to activate sprinklers.
Firefighter II 1679