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Fire Detection and Suppression
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Fire Detection and Suppression

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  1. Fire Detection and Suppression Chapter 2 Fire Detection and Signaling Systems

  2. Fire Detection and Signaling Systems The early detection of a fire and the signaling of an appropriate alarm remain the most significant factors in preventing large losses from occurring. Fire Detection and Signaling Systems

  3. Standards and Codes • Component tests by nationally recognized labs • Underwriters Laboratories • Factory Mutual • Codes • NFPA 70, National Electrical Code • NPFA 72, The National Fire Alarm Code • Local codes and ordinances Fire Detection and Signaling Systems

  4. Basic System Components • System control unit (alarm panel) • Brain of system • Processes alarm signals from actuating devices and transmits them to the local or other alerting system Fire Detection and Signaling Systems

  5. Basic System Components (cont.) • Power supply • Primary power supply • Public electric utility • Engine-driven generator • Secondary power supply • Storage battery and charger • Engine-driven generator and 4-hour storage battery • Multiple engine-driven generators • Trouble signal power supply Fire Detection and Signaling Systems

  6. Basic System Components (cont.) • Initiating devices: manual pull stations, heat detectors, smoke detectors, flame detectors, waterflow devices, tamper switches, and combination detectors • Notification appliances: bells, buzzers, horns, recorded voice messages, strobe lights, speakers, and other warning appliances • Auxiliary services Fire Detection and Signaling Systems

  7. Types of Fire Alarm Systems • Selection factors • Level of life-safety hazard • Structural features of the building • Level of hazard presented by the contents of the building • Availability of fire suppression resources • State and local code requirements (Continued) Fire Detection and Signaling Systems

  8. Types of Fire Alarm Systems (cont.) • Local system • Noncoded local alarm • Simultaneous operation of all alarm-indicating devices • Only practical in small occupancies with limited number of rooms • Master coded local alarm • Serves the premises as a local control unit and receives input from other fire alarm control units • Used in occupancies that use the alarm signals for other purposes (Continued) Fire Detection and Signaling Systems

  9. Types of Fire Alarm Systems • Local system (cont.) • Zoned/annunciated alarm • Identifies fire location quickly and accurately • Alarm-initiating devices arranged in circuits or zones • Initiating device sounds alarm and lights corresponding lamp on control unit • Annunciator panel remote from control panel • Coded signals • Presignal alarm (Continued) Fire Detection and Signaling Systems

  10. Types of Fire Alarm Systems (cont.) • Auxiliary system • Facility that receives signals where personnel are always present to respond • Initiation devices • Local requirements and policies • Types of auxiliary systems • Local energy system • Shunt system • Parallel telephone system (Continued) Fire Detection and Signaling Systems

  11. Types of Fire Alarm Systems (cont.) • Remote station system • Connected to dispatch center by means other than municipal fire alarm box system • Local alarm capability • Monitoring options (Continued) Fire Detection and Signaling Systems

  12. Types of Fire Alarm Systems (cont.) • Proprietary system • Used to protect large buildings or facilities • Systems for individual buildings or areas wired into common receiving point • Wide-ranging capabilities (Continued) Fire Detection and Signaling Systems

  13. Types of Fire Alarm Systems (cont.) • Central station system • Similar to proprietary system but receiving point is an outside, contracted central station • Alarm activation information received by central station employees, who initiate emergency response (Continued) Fire Detection and Signaling Systems

  14. Types of Fire Alarm Systems (cont.) • Emergency voice/alarm communications system • Supplements other systems • Communicates detailed information to occupants and fire fighting personnel • One-way/two-way Fire Detection and Signaling Systems

  15. Manual Alarm-Initiating Devices • General requirements • Mounting and distribution • Generally not required in fully sprinklered structures • Outmoded “broken glass” pull stations • Coded versus noncoded pull stations • Single-action and double-action pull stations Fire Detection and Signaling Systems

  16. Automatic Alarm-Initiating Devices • Continuously monitor atmosphere • Four basic types • Heat detectors • Smoke detectors • Fire-gas detectors • Flame detectors Fire Detection and Signaling Systems

  17. Heat Detectors • Fixed temperature heat detectors • Fusible links/frangible bulbs • Continuous line detector • Bimetallic detector • Rate-of-rise heat detector • Pneumatic rate-of-rise spot detector (Fig. 2.34) • Pneumatic rate-of-rise line detector (Fig. 2.35) • Rate compensated detector (Fig. 2.36) • Thermoelectric detector Fire Detection and Signaling Systems

  18. Smoke Detectors • Photoelectric smoke detector • Projected beam (Fig. 2.37) • Refractory photocell (Fig. 2.38) • Ionization smoke detector (Fig. 2.39) • Dual chamber • Air-sampling smoke detectors • Cloud chamber (Fig. 2.40) • Second type (Fig. 2.41) (Continued) Fire Detection and Signaling Systems

  19. Smoke Detectors (cont.) • Limitations • May not provide early warning of a fire developing on another level of a building • May not detect fire developing on the other side of a closed door • May not be effective when fire is caused by explosions resulting from careless housekeeping Fire Detection and Signaling Systems

  20. Flame Detectors • Types • Ultraviolet (UV) Fig. (2.42a) • Infrared (IR) Fig. (2.42b) • Fast to respond • Frequent false alarms Fire Detection and Signaling Systems

  21. Fire Gas Detectors • Monitors levels of gases released by combustion • Carbon dioxide • Carbon monoxide • Faster than heat detectors but slower than smoke detectors Fire Detection and Signaling Systems

  22. Combination Detectors • Various possible combinations • Fixed rate/rate-of-rise detectors • Heat/smoke detectors • Smoke/fire gas detectors • Offer benefits of both systems and increase responsiveness to fire conditions Fire Detection and Signaling Systems

  23. Acceptance Testing • Should be observe by representatives of building owner, fire department, system installer, and system manufacturer. • All functions of the fire detection and signaling system should be operated: • All alarm-indicating and alarm-initiating devices • Restorable heat detectors • Response of outside entities responsible for monitoring the system Fire Detection and Signaling Systems

  24. General Inspections • Fire department participation • Checkpoints • Condition of wiring and batteries • All equipment free of foreign materials • Adequate clearance around system control units, recording instruments, and other devices Fire Detection and Signaling Systems

  25. Inspecting and Service Testing Initiating Devices (cont.) • Manual alarm-initiating devices • Automatic alarm-initiating devices • Detectors must not be damaged or painted. • Replace or send the following detectors to a recognized testing laboratory for testing: • Detectors on systems that are being restored to service after a period of disuse • Detectors that are obviously corroded (Continued) Fire Detection and Signaling Systems

  26. Inspecting and Service Testing Initiating Devices (cont.) • Automatic alarm-initiating devices • Replace or send the following detectors to a recognized testing laboratory for testing (cont.): • Detectors that have been painted over, even if attempts were made to clean them • Detectors that have been mechanically damaged or abused • Detectors on circuits that were subjected to current surges, overvoltages, or lightning strikes (Continued) Fire Detection and Signaling Systems

  27. Inspecting and Service Testing Initiating Devices (cont.) • Automatic alarm-initiating devices • Replace or send the following detectors to a recognized testing laboratory for testing (cont.): • Detectors subjected to foreign substances that might affect their operation • Detectors subjected to either direct flame, excessive heat, or smoke damage • Testing • Nonrestorable • Restorable Fire Detection and Signaling Systems

  28. Inspecting System Control Units • Control panel switches and functions • Auxiliary devices • Receiving signals Fire Detection and Signaling Systems

  29. System Testing Timetables • Local systems: local guidelines • Central station systems: monthly • Auxiliary systems: monthly (noncoded fire alarm boxes: monthly) • Remote station and proprietary systems: authority having jurisdiction • Emergency voice/alarm systems: quarterly • NOTE: In all cases, check the most current edition of NFPA 72, National Fire Alarm Code. Fire Detection and Signaling Systems

  30. Record Keeping • Maintaining Files and Records • Documents: • Inspection reports, forms, and letters • Violation notices • Summonses • Plans review comments, approvals, and drawings • Fire reports • Investigations • Permits and certificates issued (Continued) Fire Detection and Signaling Systems

  31. Record Keeping • Maintaining Files and Records (cont.) • Occupancies: • Those that have been issued a permit, certificate, or license • Those that contain automatic fire suppression or detection systems • Those that conduct hazardous operations or routinely house hazardous materials • Duration: life of structure • Public record (Continued) Fire Detection and Signaling Systems

  32. Record Keeping (cont.) • Written records • File for each inspected property • Cataloging and storage • Electronic records • Two primary methods of entering data: • Inspectors use laptop computers or handheld electronic data recording equipment during the inspection. • Inspectors use written forms during the inspection and then enter the information upon returning to the office. (Continued) Fire Detection and Signaling Systems

  33. Record Keeping (cont.) • Electronic records (cont.) • Considerations in computer system management • How will the information be filed? • How can the information be retrieved? • What portion of the information will be stored in a read-only format? • What personnel will be given access to retrieve information from the system? • What information can be released to the public? Fire Detection and Signaling Systems