Essentials of Fire Fighting,

1

• Essentials of Fire Fighting,
• 5th Edition

Chapter 16 Fire Detection, Alarm, and
Suppression Systems Firefighter II
2
Chapter 16 Lesson Goal

• After completing this lesson, the 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).

3
Specific Objectives

• 1. Describe types of heat detectors.
• 2. Describe types of smoke detectors/alarms.
• 3. Explain how flame detectors and fire-gas
  detectors operate.

(Continued)
4
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.

(Continued)
5
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.

6
Fixed-Temperature Heat Detectors

• Relatively inexpensive compared to other types of
  systems
• Can be slowest to activate
• Activate when heated to temperature for which
  rated

(Continued)
7
Fixed-Temperature Heat Detectors

• Installed in highest portions of room
• Should have activation temperature rating
  slightly above highest ceiling temperatures
  normally inspected in space

(Continued)
8
Fixed-Temperature Heat Detectors

• Activate by one or more of three mechanisms
• Fusible device
• Frangible bulb
• Continuous line detector

9
Rate-of-Rise Heat Detectors

• Operate on assumption that 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

(Continued)
10
Rate-of-Rise Heat Detectors

• Can be initiated at room temperature far below
  that required for initiating fixed-temperature
  device
• Reliable, not subject to false activations
• Pneumatic rate-of-rise spot detector

(Continued)
11
Rate-of-Rise Heat Detectors

• Pneumatic rate-of-rise line detector
• Rate-compensated detector
• Thermoelectric detector

12
Smoke Detectors

• Detect presence of smoke must transmit signal to
  another device that sounds alarm
• Respond to smoke or other products of combustion
• Preferred over heat detectors

13
Smoke Alarms

• Capable of
• Detecting presence of smoke
• Sounding an alarm

14
Photoelectric Smoke Detectors

• Use photoelectric cell coupled with tiny light
  source
• Function in two ways to detect smoke

15
Ionization Smoke Detectors

• Detect minute particles, aerosols produced during
  combustion
• Use a tiny amount of radioactive material to
  ionize air molecules as they enter chamber within
  detector

(Continued)
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Ionization Smoke Detectors

• Respond satisfactorily to most fires
• Respond faster to flaming fires than smoldering
  ones

17
Power Sources of Smoke Alarms

• Battery-operated
• Household current

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Flame Detectors

• Types
• Among most sensitive detectors used to detect
  fires
• Prone to being activated by nonfire conditions

(Continued)
19
Flame Detectors

• Usually positioned in areas where other light
  sources unlikely
• Positioned to have unobstructed view of protected
  area

(Continued)
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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

21
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

(Continued)
22
Fire-Gas Detectors

• Can be more discriminating than other types
• Can be designed to be sensitive only to specific
  gases

(Continued)
23
Fire-Gas Detectors

• Use semiconductors/catalytic elements to sense
  gas, transmit signal to initiate alarm
• Not used as frequently as other types

24
Combination Detectors

• Various combinations of previously described
  means of detection may be used in single device

25
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

(Continued)
26
Indicating Devices

• Others use speakers that broadcast prerecorded
  evacuation instructions
• May include visual alarm indicators to
  accommodate special circumstances/populations

(Continued)
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Indicating Devices

• May include strobe indicators Must meet
  requirements of Americans with Disabilities Act
  in areas where there may be people with hearing
  impairments

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Automatic Alarm Systems

• Transmit signal to off-site location to summon
  organized assistance
• Produce automatic response upon activation of
  local alarm
• May be installed to complement wet-pipe or
  dry-pipe sprinkler systems

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Auxiliary Systems

• Local energy systems
• Shunt systems
• Parallel telephone systems

30
Remote Station Systems

• Similar to auxiliary systems but connected to
  fire department telecommunication center
  directly/through answering service by some means
  other than municipal fire alarm box system

(Continued)
31
Remote Station Systems

• Can be connected by leased telephone line or
  radio signal on dedicated frequency
• Common in localities not served by central
  station systems

(Continued)
32
Remote Station Systems

• May transmit coded or noncoded signal
• Must have ability to transmit trouble signal to
  fire alarm center when system impaired

(Continued)
33
Remote Station Systems

• May not have local alarm capabilities if
  evacuation is not desired action in fire
• May be monitored by entity besides fire department

34
Proprietary Systems

• Used to protect large commercial, industrial
  buildings, high-rise buildings, groups of
  commonly owned buildings in single location

(Continued)
35
Proprietary Systems

• Each building/area has own system wired into a
  common receiving point somewhere on facility
• The receiving station
• Capabilities

36
Central Station Systems

• Very similar to proprietary systems 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

(Continued)
37
Central Station Systems

• Central station is alarm company that contracts
  with individual customers

(Continued)
38
Central Station Systems

• When alarm initiated at contracting occupancy,
  central station employees take information,
  initiate appropriate emergency response
• Response usually includes calling fire
  department, representatives of protected occupancy

(Continued)
39
Central Station Systems

• Alarm systems at protected property and central
  station most commonly connected by supervised
  telephone lines

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Supervising Fire Alarm Systems

• Designed to be self-supervising
• Older systems
• Newer systems

(Continued)
41
Supervising Fire Alarm Systems

• Sounds of alarm, trouble signals may differ with
  each brand
• Many fixed fire suppression systems depend on
  signal from manual pull station/from automatic
  fire detection device to trigger suppression
  system

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Auxiliary Services Available on Newer Systems

• Shutting down, altering airflow in heating,
  ventilating, and air-conditioning (HVAC) systems
  for smoke control
• Closing smoke/fire-rated doors, dampers

(Continued)
43
Auxiliary Services Available on Newer Systems

• Facilitating evacuation by increasing air
  pressure in stairwells to exclude smoke
• Overriding elevator controls
• Monitoring operation of commercial incinerator
  management systems

(Continued)
44
Auxiliary Services Available on Newer Systems

• Monitoring refrigeration systems, cold-storage
  areas
• Controlling personnel access to hazardous
  process/storage areas
• Detecting combustible/toxic gases

45
Principle Parts of Automatic Sprinkler System

• Water supply
• Sprinkler valve
• Alarm
• Manual valve
• System drain

(Continued)
46
Principle Parts of Automatic Sprinkler System

• Test connection
• Sprinkler head
• Riser
• Feed main
• Cross mains

47
Sprinklers

• Discharge water after release of cap or plug
  activated by some heat-responsive element such as
  fusible link

(Continued)
48
Sprinklers

• Identified by temperature at which designed to
  operate, either by color-coding, using different
  colored liquid, stamping temperature on sprinkler

(Continued)
49
Sprinklers

• Fusible link
• Frangible bulb

(Continued)
50
Sprinklers

• Chemical pellet

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Sprinkler Position

• Pendant
• Upright

(Continued)
52
Sprinkler Position

• Sidewall
• Special-purpose

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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

(Continued)
54
Sprinkler Storage

• In many jurisdictions, job of changing sprinklers
  must be performed by representatives of
  buildings occupants qualified to perform work on
  sprinkler systems

(Continued)
55
Sprinkler Storage

• In other jurisdictions, firefighters allowed to
  replace fused/damaged sprinklers to restore
  system to service sooner

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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

(Continued)
57
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

(Continued)
58
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 2½-inch
  (65 mm) or larger hoses should be attached to the
  FDC

(Continued)
59
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

60
Water Supply

• Departmental preincident plans may identify the
  pressure at which a sprinkler system should be
  supported

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Wet-Pipe Systems

• Used in locations where temperatures below 40F
  (4C) not expected
• Simplest type of automatic fire sprinkler system

(Continued)
62
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

(Continued)
63
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.

(Continued)
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Wet-Pipe Systems

• May be equipped with retarding device as part of
  alarm check valve

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Dry-Pipe Systems

• Used in locations where piping may be subjected
  to temperatures below 40F (4C)

(Continued)
66
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

(Continued)
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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

(Continued)
68
Dry-Pipe Systems

• Larger systems may have several-minute delay
  while air expelled from system

69
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

(Continued)
70
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

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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

(Continued)
72
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

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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

(Continued)
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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

(Continued)
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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

(Continued)
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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 1½-inch (38 mm) connection

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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.

(Continued)
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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.

79
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.

(Continued)
80
Review Questions

• 4. What is a proprietary automatic alarm
  system?
• 5. Describe commonly used release mechanisms to
  activate sprinklers.