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Understanding Portable Fire Extinguishers for Firefighters

Gain essential knowledge on portable fire extinguishers for quick and effective firefighting in diverse situations. Explore classes of fire, agents used, and safety precautions. Improve your fire extinguishing skills!

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Understanding Portable Fire Extinguishers for Firefighters

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  1. Portable Fire extinguisher

  2. MOTIVATION Portable fire extinguishers can provide the firefighter with another tool for fire fighting. Of all the equipment used by firefighters, the portable fire extinguisher is probably the least understood. It is important that firefighters have a working knowledge of portable fire extinguishers, especially since they are perhaps the most readily available firefighting tools at the firefighter’s disposal. We live in a world regulated by codes and standards, therefore, in almost any commercial or industrial building, and a large percentage of residential structures, there are portable extinguishers. The firefighter must understand how fire extinguishers work, not only to perform better at fires, but to better educate the public as to how portable fire extinguishers play a part in fire prevention. The extinguisher is an excellent tool for combating small, incipient stage fires. With the speed that a firefighter can use an extinguisher, it is much easier and faster than using an attack line. However, only extensive training will prepare the firefighter in the appropriate use of fire extinguishers.

  3. FIRE EXTINGUISHERS

  4. The Fire Triangle Fuel Oxygen Oxygen Heat Heat Fuel Fuel Oxygen Fuel Fuel Oxygen Oxygen Heat Heat Heat

  5. REVIEW OF CLASSES OF FIRE • Class A -Ordinary Combustibles: Wood, Cloth, Paper, Rubber, Plastic • Class B -Flammable Liquids: Gasoline, Oil, Lacquer, Paint, Mineral Spirits, and Alcohol • Class C -Energized Electrical Equipment: Household Appliances, Computers, Transformers, and Overhead Transmission Lines • Class D -Combustible Metals: Aluminum, Magnesium, Titanium, Zirconium, Sodium, and Potassium • Class K –Combustible Cooking Media: Vegetable or Animal Oils and Fats

  6. AGENTS USED IN FIRE EXTINGUISHERS • Pump tank & backpack pump (water). • Stored pressure (water). • AFFF (aqueous film forming foam). • Halon 1211 (bromochlorodifluromethane). • Halon 1301 (bromotrifluoromethane). • Co2 (liquefied compressed gas). • Dry Chemical (ordinary and multipurpose).

  7. STORED PRESSURE VS PUMP TANK WATER • Stored pressure can be used on small Class A fires, small hot spots especially during overhaul operations, and chimney fires. • The difference between the two is that the air pressurized uses air pressure or nitrogen gas to expel the water, whereas, the pump tank water is manually pumped to siphon water.

  8. HALON EXTINGUISHERS • Usually used to protect energized electrical equipment (Class C fires) found in computer server rooms, etc. • The Montreal Protocol on Substances that Deplete the Ozone Layer requires a complete phaseout of the production of halogens by the year 2000. The U.S. stopped producing halogens at the end of 1993. However, these units may still be found.

  9. WARNING When halon is used to extinguish a fire, it decomposes and liberates toxic components, so these agents should not be used in unventilated, confined spaces.

  10. CARBON DIOXIDE EXTINGUISHERS • CO2 extinguishers are effective in extinguishing Class B and C fires. • Carbon dioxide gas displaces available oxygen and smothers the fire. Re-ignition is a danger.

  11. CARBON DIOXIDE EXTINGUISHERS CAUTION: Never mix or contaminate dry chemicals with any other type of agent because they may chemically react and cause a dangerous rise in pressure inside the extinguisher.

  12. DRY CHEMICAL EXTINGUISHERS • Dry chemical agents are for use on Class A-B-C fire and/or Class B-C fires. • The following are commonly used dry chemicals: Sodium bicarbonate Potassium bicarbonate Urea-potassium bicarbonate Potassium chloride Monoammonium phosphate

  13. TYPES OF HANDHELD DRY CHEMICAL EXTINGUISHERS • Stored-pressure –similar in design to the air-pressurized water extinguisher, and a constant pressure of about 200 psi. • Cartridge-operated –employs a pressure cartridge connected to the agent tank which becomes pressurized by a plunger once activated. The cartridges are carbon dioxide.

  14. CO2 VS DRY CHEMICAL EXTINGUISHERS • One advantage to using a CO2 extinguisher has over a Dry Chemical fire extinguisher is that it does not leave a residue or corrode electrical contacts.

  15. WHEELED DRY CHEMICAL EXTINGUISHERS • Dry chemical wheeled units are similar to the handheld units but on a larger scale. • They are rated for Class A, Class B, and Class C fires based on the dry chemical in the unit.

  16. WHEELED DRY CHEMICAL EXTINGUISHERS CAUTION: The top of the extinguisher should be pointed away from the firefighter or other personnel when pressurizing the unit. Because of the size of the nozzle, the firefighter should be prepared for a significant nozzle reaction when it is opened.

  17. DRY POWDER EXTINGUISHERS • No single agent will control or extinguish metal fires! • Portable extinguishers for Class D fires come in both handheld and wheeled models. • The agent must be applied in sufficient depth to completely cover the area that is burning to create a smothering blanket. Then, a 1- to 2-inch layer of powder should be spread nearby and the burning metal shoveled onto this layer with more powder added as needed. After extinguishment, the material should be left undisturbed.

  18. CLASS K EXTINGUISHERS • Extinguishing agent is a potassium acetate with a low PH and actually lowers the temperature of the burning material even after the fire has been extinguished. • It was designed to discharge a fine mist to help prevent grease splash and fire reflash for the non-expert user at a safe distance from the fire. • It can be used on Class C and even some Class A fires and leaves no “dry chemical residue” for clean-up. • Required in the cooking areas of all Commercial buildings.

  19. CLASS K EXTINGUISHERS • Class K fire extinguishers shall be provided for hazards where there is a potential for fires involving combustible cooking media (vegetable or animal oils and fats). • Maximum travel distance shall not exceed 30 ft from the hazard to the extinguishers.

  20. CLASS K

  21. PORTABLE FIRE EXTINGUISHERS RATINGS • Class A extinguisher - rated 1-A through 40-A. • Class B extinguisher -- rated 1-B through 640-B. • Class C extinguisher -- agent tested for electrical non- conductivity. • Class D extinguisher -- rated on types of combustible metal.

  22. PORTABLE FIRE EXTINGUISHERS RATINGS • For a 1-A rating, 1 ¼ gallons of water are required. A 2-A requires 2 ½ gallons or twice the 1-A capacity. • The rating for Class B is based on the approximate square foot area of a flammable liquid fire that a nonexpert operator can extinguish.

  23. SELECTION FACTORS • Classification of the burning fuel. • Rating of the extinguisher. • Hazards to be protected. • Severity of the fire. • Atmospheric conditions. • Personnel available. • Ease of handling. • Life hazard or operational concerns.

  24. FIRE EXTINGUISHER SIZE AND PLACEMENT FOR CLASS A HAZARDS

  25. FIRE EXTINGUISHER SIZE AND PLACEMENT FOR CLASS B HAZARDS

  26. INSPECTION PROCEDURES FOR FIREFIGHTERS • External condition –no apparent damage • Hose/nozzle –in place • Weight –feels as though it contains agent • Pressure gauge (if available) –in operable range

  27. INSPECTION PROCEDURES FOR THE PUBLIC • Extinguisher in proper location & accessible. • Inspect discharge horn & nozzle. • Operating instructions legible. • Check lock pins & tamper seals. • Full of agent and/or fully pressurized. • Date of previous inspection (determined by code). • Condition of hose & fittings.

  28. RECORDS Building owners should keep the following records on maintenance and inspections: • Month. • Year. • Type of maintenance. • Date of last recharge.

  29. PORTABLE FIRE EXTINGUISHER VALUES Three important factors that determine the value of a fire extinguisher: • Serviceability. • Accessibility. • Users ability to operate.

  30. MAINTENANCE CHECK Maintenance procedures should include examination of three basic parts: • Mechanical parts. • Extinguishing agents. • Expelling means.

  31. REPAIRS • Leaking hoses, gaskets, nozzles, and loose labels can be replaced by firefighters. • Leaking, corroded, or otherwise damaged extinguisher shells or cylinders should be discarded or returned to the manufacturer for repair. • If an extinguisher shows only slight damage or corrosion but it is uncertain whether or not the unit is safe to use, it should be hydrostatically tested by either the manufacturer or a qualified testing agency.

  32. CAUTION Never attempt to repair the shell or cylinder of a defective fire extinguisher. Contact the manufacturer for instructions on where to have it repaired or replaced.

  33. HYDROSTATIC TEST INTERVAL FOR EXTINGUISHERS

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