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Portable Fire Extinguishers  Chapter 11
Learning Objectives <ul><li>Discuss the fire extinguisher classification system </li></ul><ul><li>Discuss the fire extingu...
Learning Objectives (continued) <ul><li>Describe the different types of fire extinguishers and their operation </li></ul><...
Introduction <ul><li>Portable fire extinguishers are intended for use in incipient stage where water is ineffective </li><...
Requirements for Fire Extinguishers <ul><li>Code requirements exist in all of the model codes for fire extinguishers </li>...
Fire Extinguisher Classification <ul><li>Through the classification system, extinguishing agents matched to fire hazards <...
Fire Extinguisher Ratings <ul><li>Class A and B have a number rating to indicate performance capability of the extinguishe...
Figure 11-1 Wood cribbing for Class A extinguisher test
Figure 11-3 Class C test for conductivity
Types of Fire Extinguishers <ul><li>Pumped, stored pressure, and cartridge pressure categories </li></ul><ul><li>Many supp...
Pump Extinguishers <ul><li>Require manual operation of a pump mechanism </li></ul><ul><ul><li>Creates pressure in the tank...
Stored Pressure Extinguishers <ul><li>Mix pressurized gas and extinguishing agent in the same tank </li></ul><ul><li>Gas i...
Cartridge Pressure Extinguishers <ul><li>Similar to stored pressure type, but pressurized gas is in a separate cartridge <...
Common Fire Extinguisher Agents <ul><li>Same agents used in sprinkler and suppression systems are common in fire extinguis...
Water <ul><li>One of the best agents because it absorbs more heat per pound than any other material </li></ul><ul><li>Most...
Foam <ul><li>Good agent for Class A but better for Class B fires </li></ul><ul><li>Foam forms a vapor barrier between the ...
Carbon Dioxide <ul><li>Carbon dioxide gas effective in Class B and C fires; limited use on Class A fires </li></ul><ul><li...
Dry Chemicals <ul><li>Small solid particles propelled by pressurized gas </li></ul><ul><li>When discharged, chemical smoth...
Wet Chemicals <ul><li>Wet chemical agents most effective with Class K fires </li></ul><ul><li>Water-based solutions that m...
Dry Powders <ul><li>Class D fires present a challenge </li></ul><ul><ul><li>Water is not a good choice because it can reac...
Halon and Other Clean Agents <ul><li>Halon still in use but less available </li></ul><ul><ul><li>Gradual fade-out for envi...
Figure 11-7 Extinguishing agents matched to a fire classification
Obsolete Types of Fire Extinguishers <ul><li>Obsolete extinguisher types are not safe to operate and may cause injury </li...
Obsolete Types of Fire Extinguishers (continued) <ul><ul><li>Cartridge-operated loaded stream </li></ul></ul><ul><ul><li>C...
Fire Extinguisher Operation <ul><li>Most portable fire extinguishers operate in a similar manner </li></ul><ul><li>Some sm...
Figure 11-10 Portable extinguisher pictograph
Portable Fire Extinguisher Inspection, Maintenance, and Testing <ul><li>Inspection, testing, maintenance are the keys to e...
Visual Inspections <ul><li>Valuable fire prevention activity </li></ul><ul><ul><li>General condition of the extinguisher c...
Maintenance <ul><li>Follow manufacturer’s requirements </li></ul><ul><ul><li>Involves more thorough inspection </li></ul><...
Testing <ul><li>Hydrostatic test critical on all refillable extinguishers </li></ul><ul><ul><li>Ensure extinguisher will n...
Summary <ul><li>Portable fire extinguishers </li></ul><ul><ul><li>Are intended to suppress small incipient fires </li></ul...
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Chapter 11

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Transcript of "Chapter 11"

  1. 1. Portable Fire Extinguishers Chapter 11
  2. 2. Learning Objectives <ul><li>Discuss the fire extinguisher classification system </li></ul><ul><li>Discuss the fire extinguisher rating system and to which classification of extinguishers it applies </li></ul><ul><li>Explain why a certain extinguisher classification requires a conductivity test </li></ul><ul><li>Explain the acronym PASS in relation to fire extinguisher operation </li></ul>
  3. 3. Learning Objectives (continued) <ul><li>Describe the different types of fire extinguishers and their operation </li></ul><ul><li>List the different extinguishing agents and their applications </li></ul><ul><li>Discuss the inspection, testing, and maintenance procedures for portable fire extinguishers </li></ul>
  4. 4. Introduction <ul><li>Portable fire extinguishers are intended for use in incipient stage where water is ineffective </li></ul><ul><ul><li>Useful if there is quick access, the correct type is available, and person is trained </li></ul></ul><ul><ul><li>Has fixed amount of suppression agent </li></ul></ul><ul><ul><li>Are clearly labeled and require little training </li></ul></ul><ul><li>Rapid access to the extinguisher is critical </li></ul>
  5. 5. Requirements for Fire Extinguishers <ul><li>Code requirements exist in all of the model codes for fire extinguishers </li></ul><ul><ul><li>Requirements center on use and occupancy conditions and processes </li></ul></ul><ul><li>IFC requires extinguishers installed in almost every new and existing occupancy classification </li></ul><ul><li>NFPA 10 lists the requirements for fire extinguishers </li></ul>
  6. 6. Fire Extinguisher Classification <ul><li>Through the classification system, extinguishing agents matched to fire hazards </li></ul><ul><li>Classification designated with letters </li></ul><ul><ul><li>Class A fires: ordinary combustibles </li></ul></ul><ul><ul><li>Class B fires. flammable and combustible liquids and gases </li></ul></ul><ul><ul><li>Class C fires: energized electrical equipment </li></ul></ul><ul><ul><li>Class D fires: combustible metals </li></ul></ul><ul><ul><li>Class K fires: cooking media </li></ul></ul>
  7. 7. Fire Extinguisher Ratings <ul><li>Class A and B have a number rating to indicate performance capability of the extinguisher </li></ul><ul><ul><li>Expresses how much fire the extinguisher can handle </li></ul></ul><ul><li>Class A extinguishers are tested using a wood crib on fire, allowing it to burn for a time </li></ul><ul><li>Class B extinguishers are tested with a flammable liquid fire in a pan </li></ul><ul><ul><li>Flammable liquid is usually heptane </li></ul></ul><ul><li>Class C extinguishers do not receive a rating </li></ul>
  8. 8. Figure 11-1 Wood cribbing for Class A extinguisher test
  9. 9. Figure 11-3 Class C test for conductivity
  10. 10. Types of Fire Extinguishers <ul><li>Pumped, stored pressure, and cartridge pressure categories </li></ul><ul><li>Many suppression agents: </li></ul><ul><ul><li>Water, foam, carbon dioxide, dry chemical, wet chemical, dry powder, halon, clean agents </li></ul></ul><ul><li>Some agents will not work well with a particular category of extinguisher </li></ul>
  11. 11. Pump Extinguishers <ul><li>Require manual operation of a pump mechanism </li></ul><ul><ul><li>Creates pressure in the tank to expel extinguishing agent </li></ul></ul><ul><li>Extinguishing agent is either water or antifreeze solution </li></ul><ul><li>Easy to operate and fill </li></ul><ul><li>Backpack type extinguisher has external pump </li></ul><ul><ul><li>Mechanism similar to hand-held </li></ul></ul>
  12. 12. Stored Pressure Extinguishers <ul><li>Mix pressurized gas and extinguishing agent in the same tank </li></ul><ul><li>Gas is above the agent and keeps constant pressure on the agent </li></ul><ul><li>When operated, the pressure of the gas forces the extinguishing agent out of the tank </li></ul><ul><li>Air or nitrogen frequently used as expelling gas </li></ul><ul><li>Pressure gauge indicates if pressure is sufficient </li></ul>
  13. 13. Cartridge Pressure Extinguishers <ul><li>Similar to stored pressure type, but pressurized gas is in a separate cartridge </li></ul><ul><ul><li>Attached to the side of the extinguishing tank </li></ul></ul><ul><li>Activating the extinguisher punctures the cartridge that expels the gas into the tank </li></ul><ul><li>Allows for easy maintenance of certain types of agents </li></ul><ul><ul><li>Top removes without dumping the agent or losing the gas pressure </li></ul></ul><ul><li>Good for agents that settle and need stirring </li></ul>
  14. 14. Common Fire Extinguisher Agents <ul><li>Same agents used in sprinkler and suppression systems are common in fire extinguishers </li></ul><ul><ul><li>Present in smaller amounts </li></ul></ul>
  15. 15. Water <ul><li>One of the best agents because it absorbs more heat per pound than any other material </li></ul><ul><li>Most effective on Class A fires </li></ul><ul><li>Not effective on some fuels; dangerous to use on others </li></ul><ul><li>When used in an extinguisher, extinguisher must not be exposed to cold </li></ul>
  16. 16. Foam <ul><li>Good agent for Class A but better for Class B fires </li></ul><ul><li>Foam forms a vapor barrier between the fuel and the atmosphere </li></ul><ul><li>Agent must discharge through special aspirating nozzle so that air can mix with the agent </li></ul><ul><li>Two types of foam: </li></ul><ul><ul><li>Aqueous film-forming foam </li></ul></ul><ul><ul><li>Film-forming fluoroprotein </li></ul></ul>
  17. 17. Carbon Dioxide <ul><li>Carbon dioxide gas effective in Class B and C fires; limited use on Class A fires </li></ul><ul><li>In extinguisher tank, carbon dioxide is a high-pressure liquid state </li></ul><ul><ul><li>Expands to a gas when released </li></ul></ul><ul><li>Depletes the oxygen supply </li></ul><ul><li>Must be discharged at close range to the fire because air movement carries the gas away </li></ul><ul><li>Operator must have oxygen supply available to avoid asphyxiation </li></ul>
  18. 18. Dry Chemicals <ul><li>Small solid particles propelled by pressurized gas </li></ul><ul><li>When discharged, chemical smothers the burning material </li></ul><ul><li>Not considered dangerous or toxic; do not react with flammable liquids or gases; not conductive </li></ul><ul><li>Once discharged, create a cloud that limits visibility; may cause respiratory problems </li></ul><ul><li>May leave a corrosive residue </li></ul>
  19. 19. Wet Chemicals <ul><li>Wet chemical agents most effective with Class K fires </li></ul><ul><li>Water-based solutions that mix with potassium carbonate, potassium acetate, potassium citrate </li></ul><ul><li>React with fat in the cooking medium or food to develop a soapy foam blanket on the surface </li></ul><ul><ul><li>Smothers, cools, and extinguishes the fire </li></ul></ul><ul><li>Liquid in the agent cools the cooking media adequately to maintain the foam blanket </li></ul>
  20. 20. Dry Powders <ul><li>Class D fires present a challenge </li></ul><ul><ul><li>Water is not a good choice because it can react with metals to liberate oxygen and fuel the fire </li></ul></ul><ul><li>Dry powders are one of the most effective agents </li></ul><ul><ul><li>No one powder effective on all metals </li></ul></ul><ul><li>Some agents do not work in an extinguisher </li></ul><ul><ul><li>Applied by shovel, scoop or by hand </li></ul></ul>
  21. 21. Halon and Other Clean Agents <ul><li>Halon still in use but less available </li></ul><ul><ul><li>Gradual fade-out for environmental concerns </li></ul></ul><ul><li>Leaves no residue; not conductive; more effective than the same amount of CO 2 </li></ul><ul><li>Halons are somewhat toxic and exposure can cause physical problems </li></ul><ul><ul><li>Vertigo, loss of agility, loss of coordination </li></ul></ul><ul><li>Two types still in use: 1211, 1301 </li></ul><ul><li>Inert gases generally safe for humans </li></ul>
  22. 22. Figure 11-7 Extinguishing agents matched to a fire classification
  23. 23. Obsolete Types of Fire Extinguishers <ul><li>Obsolete extinguisher types are not safe to operate and may cause injury </li></ul><ul><ul><li>Some have corrosive or conductive products </li></ul></ul><ul><li>Types of extinguishers and products requiring removal from service: </li></ul><ul><ul><li>Soda acid </li></ul></ul><ul><ul><li>Chemical foam </li></ul></ul><ul><ul><li>Vaporizing liquid </li></ul></ul><ul><ul><li>Cartridge-operated water </li></ul></ul>
  24. 24. Obsolete Types of Fire Extinguishers (continued) <ul><ul><li>Cartridge-operated loaded stream </li></ul></ul><ul><ul><li>Copper or brass shell joined by soft solder on rivets </li></ul></ul><ul><ul><li>Carbon dioxide extinguishers with metal horns </li></ul></ul><ul><ul><li>Sold charge-type AFFF extinguishers </li></ul></ul><ul><ul><li>Pressurized water manufactured prior to 1971 </li></ul></ul><ul><ul><li>Any extinguisher that must be inverted </li></ul></ul><ul><ul><li>Any stored pressure manufactured before 1955 </li></ul></ul><ul><ul><li>Any extinguishers with 4B, 6B, 8B, 12B, 16B ratings </li></ul></ul><ul><ul><li>Stored-pressure with fiberglass shells </li></ul></ul>
  25. 25. Fire Extinguisher Operation <ul><li>Most portable fire extinguishers operate in a similar manner </li></ul><ul><li>Some small enough to carry by hand; others have a cart on wheels </li></ul><ul><li>PASS for hand-held extinguishers </li></ul><ul><ul><li>Requires little or no training </li></ul></ul><ul><ul><li>Pictographs depict instructions </li></ul></ul><ul><li>Any person who might use an extinguisher should know their operation and location </li></ul><ul><ul><li>Notify other occupants to evacuate </li></ul></ul>
  26. 26. Figure 11-10 Portable extinguisher pictograph
  27. 27. Portable Fire Extinguisher Inspection, Maintenance, and Testing <ul><li>Inspection, testing, maintenance are the keys to ensuring that extinguishers work </li></ul><ul><ul><li>Involve a number of different activities that can be conducted by anyone </li></ul></ul><ul><li>Annual maintenance requires specialized training </li></ul><ul><li>Hydrostatic testing requires further training </li></ul>
  28. 28. Visual Inspections <ul><li>Valuable fire prevention activity </li></ul><ul><ul><li>General condition of the extinguisher can be determined in a short amount of time </li></ul></ul><ul><li>Inspections should take place every 30 days </li></ul><ul><li>Check the location, verify it is of the proper type, check for physical damage, etc. </li></ul><ul><li>Determine if pressure gauge within normal range </li></ul><ul><li>Note deficiencies found in prior inspections </li></ul>
  29. 29. Maintenance <ul><li>Follow manufacturer’s requirements </li></ul><ul><ul><li>Involves more thorough inspection </li></ul></ul><ul><li>Usually yearly, but could be sooner </li></ul><ul><li>All extinguishers require disassembling and internal examination at regular intervals </li></ul><ul><ul><li>Look for conditions that could impair the extinguisher </li></ul></ul><ul><li>Some maintenance activities can be dangerous </li></ul><ul><ul><li>Personnel require proper training and tools </li></ul></ul>
  30. 30. Testing <ul><li>Hydrostatic test critical on all refillable extinguishers </li></ul><ul><ul><li>Ensure extinguisher will not fail due to unnoticed conditions </li></ul></ul><ul><li>Test intervals range from five to ten years or on discovery of physical damage or corrosion </li></ul><ul><li>Typical procedure: </li></ul><ul><ul><li>Disassemble and fill with water </li></ul></ul><ul><ul><li>Immerse component in water </li></ul></ul><ul><ul><li>Pressurize component for desired amount of time </li></ul></ul>
  31. 31. Summary <ul><li>Portable fire extinguishers </li></ul><ul><ul><li>Are intended to suppress small incipient fires </li></ul></ul><ul><ul><li>Hold a fixed amount of suppression agent, so access should be quick </li></ul></ul><ul><ul><li>Must have knowledgeable operator </li></ul></ul><ul><li>Extinguishing agent must be suitable for the type of fire </li></ul><ul><li>Three categories of extinguishers: pumped, stored-pressure, cartridge pressure </li></ul>
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