Manchaca Fire / Rescue Probationary Firefighter Academy. Fire Extinguishers. SFFMA Section 29: Fire Extinguishers

Transcription

1 Manchaca Fire / Rescue Probationary Firefighter Academy Fire Extinguishers SFFMA Section 29: Fire Extinguishers

2 Portable extinguishers can be used by firefighters in several scenarios. For use on small fires, saving time and effort of deploying a hoseline In conjunction with hoseline deployment to keep a larger fire in check as the hoseline is placed into service To extinguish special fires such as electrically charged fuels, fuel spills, cooking oil fires, or metal fires

3 Modes of Extinguishment Extinguisher agents extinguish fires by: Smothering (excluding oxygen) Example: Carbon Dioxide / Dry Powder Cooling (lowering fuel below its ignition temperature) Example: Water Breaking Chemical Chain Reaction Example: Dry Chemical Saponification (reacting with the fuel to form a soapy film) Example: Class K agents

4 Extinguisher Classification Extinguishers are classified as to which types of fires they are best suited. The extinguisher must be matched to the fuel that is burning.

5 Extinguisher Ratings C, D, and K extinguishers have no associated rating with their classification. The classification simply states that the extinguisher is suitable for that fuel type but gives no indication as to the volume of fire it can handle. A and B extinguishers have a numeric rating associated with their classification. This numeric rating gives an indication as to the size of fire the extinguisher should be able to handle.

6 Classification System Letter indicates Class 2A: 10B:C Number indicates Relative extinguishing ability 2A indicates twice the extinguishing ability of a 1A 10B indicates Square foot area of fuel a non-expert can extinguish (Firefighters / expert users can be expected to extinguish 2 ½ times this amount)

7 Types of Extinguishers Extinguishers come in a variety of configurations and methods of propelling the agent onto the fire. Pump Type Stored Pressure Self-Pressurized Cartridge Operated

8 Types of Extinguishers Pump Type: Uses a mechanically actuated pump to propel agent from the extinguishers. Commonly used for water agent extinguishers (pump cans) Stored Pressure: The agent and the propellant gas are stored together in the same container. This is the typed used for the majority of extinguishers.

9 Types of Extinguishers Self-Pressurized: Carbon Dioxide extinguishers have significant pressure from the gas itself to propel it out of the container, no other propellant is needed. Due to this, CO2 extinguishers do not have a pressure gauge on them Cartridge Operated: The agent is in its own container and the propellant gas is in a separate cylinder. When activated, the propellant gas empties into the agent chamber and propels the agent our of the extinguisher

10 Extinguisher Agents: Carbon Dioxide Are effective on Class B and Class C fires Are found as both hand-held units and wheeled units Are most commonly found at airports and industrial facilities Are stored under its own pressure since it is a liquefied gas inside the container Extinguish by displacing available oxygen and smothering fire

11 Extinguisher Agents: Carbon Dioxide Discharge has a limited reach. Fuel may reignite (CO 2 produces no vapor-suppressing film on the fuel surface). Nozzle may freeze during discharge; touching it may cause frostbite. (Gloves are essential)

12 Extinguisher Agents: Dry Chemical Are effective on Class A-B-C fires and/or Class B-C fires depending on the agent used Use nitrogen or carbon dioxide for pressurization Should never mix or contaminate chemical agents; they may react and cause a dangerous rise in pressure inside extinguisher Common Dry Chem Agents Sodium Bicarbonate Potassium Bicarbonate Urea-potassium Bicarbonate Monoammonium Phosphate Potassium Chloride

13 Extinguisher Agents: Dry Chemical Chemical cloud may reduce visibility and create respiratory problems. Some cannot be used with foam because they will degrade the foam blanket. Many are corrosive to metals. Wheeled models... Extinguisher hose must be stretched out completely Removing the hose can be difficult after it is charged Powder can sometimes pack in sharp bends in hose

14 Extinguisher Agents: Dry Powder Dry POWDER is used on Class D fires. Dry CHEMICAL is used on ABC or BC fires Should be applied gently to avoid breaking any crust that may form over burning metal Extinguish by creating a smothering blanket Gently rain down with extinguisher Shovel agent onto fire taking care to avoid breaking any crust that forms Sandwich if on a combustible surface: Cover with powder. Spread a 1- to 2-inch (25 mm to 51 mm) layer of powder nearby. Shovel burning metal onto this layer with more powder added as needed.

15 Extinguisher Agents: Wet Chemical Wet chemical agents are the same chemicals used in commercial kitchen fire extinguishing systems. They react with the grease, creating a soapy film across the surface that both smothers and cools the fuel. The agent will be in stored pressure extinguishers that appear similar to pressurized water extinguishers.

16 Application of Agent Factors to consider when selecting a portable extinguisher. Classification of the burning fuel Rating of the extinguisher Hazards to be protected Severity of the fire Atmospheric conditions (dispersion of agent) Availability of trained personnel Ease of handling extinguisher Any life hazard or operational concerns

17 Application of Agent Carry extinguisher by handle in upright position. Do not run. Make sure that you are within stream reach before discharging agent. (check extinguisher label for recommended distance) Be familiar with specific operating instructions. Watch for hot spots, particularly flammable liquid hot spots, that might reflash. Always back away from an extinguished fire

18 Application of Agent The acronym PASS provides us with the proper technique for use of fire extinguishers: P Pull Pin: pull the safety pin that prevents accidental activation of the extinguisher A Aim: aim the extinguisher at the base of the fire. Aiming at the flame cause the agent to miss the actual fuel source and waste agent. S Squeeze: squeeze the handle to allow agent to discharge from the extinguisher S Sweep: sweep the agent stream back and forth across the base of the fire. Start at the front of the fire and work your way back

19 Using Fire Extinguishers VIDEO: Using Stored Pressure Fire Extinguishers VIDEO: Using Cartridge Type Fire Extinguishers