0. Essentials of Fire Fighting, 5th Edition
Chapter 16 — Fire Detection, Alarm, and Suppression Systems
Firefighter II

1. 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).
Firefighter II

2. 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.
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Firefighter II

3. 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

4. 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

5. 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
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Firefighter II

6. Fixed-Temperature Heat Detectors
Installed in highest portions of room
Should have activation temperature rating slightly above highest ceiling temperatures normally inspected in space
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Firefighter II

7. Fixed-Temperature Heat Detectors
Activate by one or more of three mechanisms
Fusible device
Frangible bulb
Continuous line detector
Firefighter II

8. 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 15°F (-11°C to -9°C) in one minute
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Firefighter II

9. 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
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Firefighter II

10. Rate-of-Rise Heat Detectors
Pneumatic rate-of-rise line detector
Rate-compensated detector
Thermoelectric detector
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11. 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
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12. Smoke Alarms Capable of Detecting presence of smoke Sounding an alarm
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13. Photoelectric Smoke Detectors
Use photoelectric cell coupled with tiny light source
Function in two ways to detect smoke
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14. 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
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Firefighter II

15. Ionization Smoke Detectors
Respond satisfactorily to most fires
Respond faster to flaming fires than smoldering ones
Firefighter II

16. Power Sources of Smoke Alarms
Battery-operated
Household current
Firefighter II

17. Flame Detectors
Types
Among most sensitive detectors used to detect fires
Prone to being activated by nonfire conditions
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Firefighter II

18. 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

19. 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

20. 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

21. 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

22. Fire-Gas Detectors
Use semiconductors/catalytic elements to sense gas, transmit signal to initiate alarm
Not used as frequently as other types
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23. Combination Detectors
Various combinations of previously described means of detection may be used in single device
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24. 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

25. 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

26. 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

27. 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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28. Auxiliary Systems Local energy systems Shunt systems
Parallel telephone systems
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29. 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
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Firefighter II

30. 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
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Firefighter II

31. Remote Station Systems
May transmit coded or noncoded signal
Must have ability to transmit trouble signal to fire alarm center when system impaired
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Firefighter II

32. 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
Firefighter II

33. Proprietary Systems
Used to protect large commercial, industrial buildings, high-rise buildings, groups of commonly owned buildings in single location
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Firefighter II

34. Proprietary Systems
Each building/area has own system wired into a common receiving point somewhere on facility
The receiving station
Capabilities
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35. Central Station Systems
Very similar to proprietary systems; instead of having alarm-receiving point monitored by occupant’s representative on protected premises, receiving point is at off-site, contracted service point called a central station
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36. Central Station Systems
Central station is alarm company that contracts with individual customers
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Firefighter II

37. 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
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Firefighter II

38. Central Station Systems
Alarm systems at protected property and central station most commonly connected by supervised telephone lines
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39. Supervising Fire Alarm Systems
Designed to be self-supervising
Older systems
Newer systems
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Firefighter II

40. 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
Firefighter II

41. 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
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Firefighter II

42. 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
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Firefighter II

43. Auxiliary Services Available on Newer Systems
Monitoring refrigeration systems, cold-storage areas
Controlling personnel access to hazardous process/storage areas
Detecting combustible/toxic gases
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44. Principle Parts of Automatic Sprinkler System
Water supply
Sprinkler valve
Alarm
Manual valve
System drain
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Firefighter II

45. Principle Parts of Automatic Sprinkler System
Test connection
Sprinkler head
Riser
Feed main
Cross mains
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46. Sprinklers
Discharge water after release of cap or plug activated by some heat-responsive element such as fusible link
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Firefighter II

47. Sprinklers
Identified by temperature at which designed to operate, either by color-coding, using different colored liquid, stamping temperature on sprinkler
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48. Sprinklers
Fusible link
Frangible bulb
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Firefighter II

49. Sprinklers
Chemical pellet
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50. Sprinkler Position
Pendant
Upright
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Firefighter II

51. Sprinkler Position
Sidewall
Special-purpose
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52. 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

53. Sprinkler Storage
In many jurisdictions, job of changing sprinklers must be performed by representatives of building’s occupants qualified to perform work on sprinkler systems
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Firefighter II

54. Sprinkler Storage
In other jurisdictions, firefighters allowed to replace fused/damaged sprinklers to restore system to service sooner
Firefighter II

55. 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
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Firefighter II

56. 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

57. 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
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Firefighter II

58. 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

59. Water Supply
Departmental preincident plans may identify the pressure at which a sprinkler system should be supported
Firefighter II

60. Wet-Pipe Systems
Used in locations where temperatures below 40°F (4°C) not expected
Simplest type of automatic fire sprinkler system
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Firefighter II

61. 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

62. 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

63. Wet-Pipe Systems
May be equipped with retarding device as part of alarm check valve
Firefighter II

64. Dry-Pipe Systems
Used in locations where piping may be subjected to temperatures below 40°F (4°C)
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Firefighter II

65. 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

66. 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

67. Dry-Pipe Systems
Larger systems may have several-minute delay while air expelled from system
Firefighter II

68. 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

69. 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

70. 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

71. 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

72. 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

73. 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 dwelling’s domestic water system
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Firefighter II

74. 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
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Firefighter II

75. 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
Firefighter II

76. 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

77. 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

78. 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

79. Review Questions 4. What is a proprietary automatic alarm system?
5. Describe commonly used release mechanisms to activate sprinklers.
Firefighter II