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Fire Detection and Suppression

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  1. Fire Detection and Suppression Chapter 1 Fire Extinguishing Agents and Portable Fire Extinguishers

  2. Portable Fire Extinguishers • First line of defense against incipient fires of limited size • For a portable extinguisher to be effective, the following requirements must be met: • Extinguisher must be readily accessible. • Extinguisher must be in working order. • Extinguisher must be suitable for the hazard • Operator must know how to use extinguisher. Fire Extinguishing Agents and Portable Fire Extinguishers

  3. Classification of Fires by Burning Characteristics • Class A: ordinary combustibles • Class B: flammable and combustible liquids and gases • Class C: energized electrical equipment • Class D: combustible metals • Class K: cooking devices that contain or use combustible vegetable or animal oils and fats Fire Extinguishing Agents and Portable Fire Extinguishers

  4. Extinguisher Symbols • Pictorial system (Fig. 1.2) • Letter system (Table 1.1) Fire Extinguishing Agents and Portable Fire Extinguishers

  5. How Extinguishers Are Rated • UL 711, Standard For Rating and Fire Testing Fire Extinguishers • Rating criteria • Intended use (fire class) • Fire fighting capability • Volume and duration of agent discharge • Range of discharge • Hydrostatic testing of the agent vessel and discharge hose Fire Extinguishing Agents and Portable Fire Extinguishers

  6. Extinguisher Rating Tests • Class A • Wood crib test • Wood panel test • Excelsior test • Class B: 2-inch (50 mm) layer of flammable liquid • Class C: nonconductivity (Continued) Fire Extinguishing Agents and Portable Fire Extinguishers

  7. Extinguisher Rating Tests (cont.) • Class D: tested for specific types of metals • Magnesium fire tests • Sodium And Potassium Fire Tests • Class K: UL Standard 300 Fire Extinguishing Agents and Portable Fire Extinguishers

  8. Extinguishing Agents • Water • Antifreeze agents • Alkaline mixtures • Carbon dioxide (CO2) • Aqueous film forming foam (AFFF) • Film forming fluoroprotein (FFFP) (Continued) Fire Extinguishing Agents and Portable Fire Extinguishers

  9. Extinguishing Agents (cont.) • Halogenated agents • Halotron and other replacement agents • Dry chemical agents • Ordinary • Sodium bicarbonate • Potassium bicarbonate • Multipurpose: monoammonium phosphate • Class D dry powders: NA-X; Met-L-X; Lith-X Fire Extinguishing Agents and Portable Fire Extinguishers

  10. Types of Fire Extinguishers • Stored-pressure • Cartridge-operated • Pump-operated • Obsolete types • Inverting • Soldered or riveted shell • Loaded stream Fire Extinguishing Agents and Portable Fire Extinguishers

  11. Selection and Distribution of Extinguishers (cont.) • General considerations • Nature of the hazard • Size of the extinguisher • Light hazard occupancy • Ordinary hazard occupancy • Extra hazard occupancy (Continued) Fire Extinguishing Agents and Portable Fire Extinguishers

  12. Selection and Distribution of Extinguishers (cont.) • Specific considerations • Chemical and physical characteristics of combustibles • Potential severity of fire • Location of extinguisher • Effectiveness of the extinguisher for the hazard • Personnel available to operate the extinguisher • Environmental conditions (Continued) Fire Extinguishing Agents and Portable Fire Extinguishers

  13. Selection and Distribution of Extinguishers • Specific considerations (cont.) • Anticipated adverse chemical reactions between the extinguishing agent and the burning material • Any health and occupational safety concerns • Inspection and service required (Continued) Fire Extinguishing Agents and Portable Fire Extinguishers

  14. Selection and Distribution of Extinguishers (cont.) • Class A extinguisher distribution factors; substitutions in ordinary- and low-hazard occupancies • Class B extinguisher distribution factors • Distance to hazard • Depth of hazard • Flammable liquid fires without depth • Flammable liquid fires with depth (Continued) Fire Extinguishing Agents and Portable Fire Extinguishers

  15. Selection and Distribution of Extinguishers (cont.) • Class C extinguisher distribution factors : • No special rules • Usually involve Class A or Class B fuels • Class D extinguisher distribution factors : • Requires analysis of specific metal present • Travel distance should not exceed 75 feet (25 m) (Continued) Fire Extinguishing Agents and Portable Fire Extinguishers

  16. Selection and Distribution of Extinguishers (cont.) • Class K extinguisher distribution factors • Employee responsibilities • Travel distance should not exceed 30 feet (10 m) Fire Extinguishing Agents and Portable Fire Extinguishers

  17. Installation and Placement of Extinguishers • General guidelines • Visible and well signed • Not blocked by storage or equipment • Near points of egress or ingress • Near normal paths of travel (Continued) Fire Extinguishing Agents and Portable Fire Extinguishers

  18. Installation and Placement of Extinguishers (cont.) • Installation guidelines • Height from floor • Temperature of environment • Snow, rain, corrosive fumes Fire Extinguishing Agents and Portable Fire Extinguishers

  19. Portable Fire Extinguishers on Fire Apparatus • General requirements: • Proper type for probable hazards • Accessible • Proper maintenance • NFPA 1901, Standard on Automotive Fire Apparatus (Continued) Fire Extinguishing Agents and Portable Fire Extinguishers

  20. Inspecting, Maintaining, and Recharging Extinguishers • Infrequent use results in tendency to ignore extinguishers • Common problems • Misplaced or stolen extinguishers • Damage from being struck by vehicle • Lost pressure • Extinguishers used and replaced without notifying proper authorities (Continued) Fire Extinguishing Agents and Portable Fire Extinguishers

  21. Inspecting, Maintaining, and Recharging Extinguishers (cont.) • Inspection: visual check to determine that an extinguisher is available and operable • Maintenance: thorough examination and performance of any needed service Fire Extinguishing Agents and Portable Fire Extinguishers

  22. Inspecting Extinguishers • Check that the extinguisher is in its proper location. • Ensure that access to the extinguisher is not obstructed by boxes, clothing, storage items, or is otherwise inaccessible. • Check the inspection tag to determine if maintenance is due. (Continued) Fire Extinguishing Agents and Portable Fire Extinguishers

  23. Inspecting Extinguishers (cont.) • Examine the nozzle or horn for obstructions. • Check lock pins or tamper seals to make sure that they are intact. • Check for signs of physical damage. • Check that the extinguisher is full of agent. • Check that the pressure gauge indicates proper reading. (Continued) Fire Extinguishing Agents and Portable Fire Extinguishers

  24. Inspecting Extinguishers (cont.) • Check collar tag for current information and/or damage. • Check that required signage is in place. • Check to see if the operating instructions on the extinguisher nameplate are legible. • Check that the extinguisher is suitable for the hazard protected. Fire Extinguishing Agents and Portable Fire Extinguishers

  25. Maintaining Extinguishers • Mechanical parts • Extinguishing agent • Expelling means Fire Extinguishing Agents and Portable Fire Extinguishers

  26. Recharging Extinguishers • Importance of following correct schedule • Using proper extinguishing agent • Pressurizing • Moisture contamination in nonwater extinguishers • Qualifications and training Fire Extinguishing Agents and Portable Fire Extinguishers

  27. Hydrostatic Testing of Portable Extinguishers • Failure of pressure vessels • Hydrostatic test: filling the cylinder with water and then applying appropriate pressure by means of a pump • Determining appropriate pressure • Signs that preclude testing an extinguisher • Record keeping Fire Extinguishing Agents and Portable Fire Extinguishers

  28. Using Portable Extinguishers Step 1: Activate alarm system. First, call appropriate fire department. Second, initiate local alarm. Step 2: Select a suitable extinguisher. Match extinguisher to fire. Analyze the type of hazard being protected and provide, in a conspicuous location, an extinguisher of the proper size and type. (Continued Fire Extinguishing Agents and Portable Fire Extinguishers

  29. Using Portable Extinguishers Step 3: Activate the extinguisher effectively. Stored pressure: remove safety pin and squeeze valve handle. Cartridge: remove nozzle from holder and depress lever that punctures cartridge seal. Step 4: Apply the extinguishing agent properly. (Continued) Fire Extinguishing Agents and Portable Fire Extinguishers

  30. Using Portable Extinguishers (cont.) • P.A.S.S. Method • Pull the pin • Aim • Squeeze • Sweep (Continued) Fire Extinguishing Agents and Portable Fire Extinguishers

  31. Using Portable Extinguishers (cont.) • Attacking Class A fires • Water-based extinguisher • Aim stream at seat of fire • Initial distance = 10–30 feet (3 m to 10 m) • AFFF extinguisher: same method as water-based • Multipurpose dry chemical • Attack fire at base • Sweep nozzle from side to side • Coat all fuel surfaces (Continued) Fire Extinguishing Agents and Portable Fire Extinguishers

  32. Using Portable Extinguishers (cont.) • Attacking Class B fires • Regular or multipurpose dry chemical extinguishers • Begin discharge at about 10 feet (3 m), sweeping leading edge of fire and moving forward. • Begin second attacks with second full extinguishers. • C02 extinguishers • Apply at close range, sweeping surface of burning liquid with overlapping strokes. • Continue discharge after initial extinguishment (Continued) Fire Extinguishing Agents and Portable Fire Extinguishers

  33. Using Portable Extinguishers (cont.) • Attacking Class C fires • Dielectric or nonconductive agent • Carbon dioxide* • Water mist* • Halon • Dry chemical (involves substantial cleanup) *Best choices • De-energize equipment if possible (Continued) Fire Extinguishing Agents and Portable Fire Extinguishers

  34. Using Portable Extinguishers (cont.) • Attacking Class D fires • Dry powder agents • Apply with extinguisher or shovel • Cover fuel with 2-inch layer • Avoid disturbing fuel • Limitations of individual agents (Continued) Fire Extinguishing Agents and Portable Fire Extinguishers

  35. Using Portable Extinguishers (cont.) • Attacking Class K fires • Class K fire extinguisher recommended • Class A:B:C or Class B:C extinguisher: reignition possible • Application • Begin from distance of 10 to 12 feet (3.5 – 4 m) • Hold application wand at edge of flames and coat surface of fuel with side-to-side sweep. • Continue to apply agent until the fire extinguisher is completely empty. Fire Extinguishing Agents and Portable Fire Extinguishers