Chapter 7 Portable Fire Extinguishers Flashcards
What stages of fire are portable fire extinguishers intended to be used?
incipient and growth
Standard for portable fire extinguishers.
NFPA 10
Portable fire extinguishers are designed by?
the type of fire they are intended to extinguish.
Class A fires
Ordinary combustibles. Wood, paper, textiles, plastic, rubber.
Class B fires
Flammable and combustible liquids and gases.
Class C fires
Involve energized electrical equipment.
Class D fires
Combustible metals and alloys. Ex: lithium, magnesium, potassium, and sodium. DRY POWDER works best.
Class K fires
Combustible cooking oils.
Name the 4 extinguishing methods that fire extinguishers use.
Smothering, Cooling, Chain breaking, Saponification
Excluding O2 from the burning process.
Smothering
Reduce the burning material below its ignition temp.
Cooling
Interrupting the chemical chain reaction in the burning process.
Chain breaking
Forming a oxygen excluded soapy foam surface.
Saponification
T of F. Extinguishing agents that work by smothering are ineffective on materials that contain their own oxidizing agent.
True
Water type extinguishers should be stored in temps above what?
40 F
All extinguishers expel their contents using one of three mechanisms. Name the three mechanism.
Manual Pump, Stored Pressure, Pressure Cartridge
List nine common types of portable fire extinguishers.
Pump-type water extinguishers. Stored-pressure water extinguishers. Water-mist stored- pressure extinguisher. Wet Chemical Stored-Pressure Extinguisher. Aqueous Film Forming Foam (AFFF) Extinguishers. Clean Agent Extinguisher. Carbon Dioxide (CO2) Extinguisher. Dry Chemical Extinguisher. Dry Powder Extinguisher.
Extinguisher intended for ground fires and small class A fires. Worn on the back. Nozzles produce a straight stream, for, or water mist.
Pump - Type Water Extingusher
Useful on all class A fires. Used to extinguish confined hot spots during overhaul. May contain a wetting agent to help the water penetrate.
Store-Pressure Water Extingusher
Use deionized water, nozzle produces a very fine spray. The deionized water makes it safe to use on electrical equipment. The fine spray enhances cooling and soaking characteristics of the water and reduces scattering of burning material.
Water-Mist Stored-Pressure Extinguisher.
Intended for class K fires. Contains a special potassium-based, low ph agent formulated to operate on the principle of saponification in which the agent combines with the oils to create a soapy foam surface over the cooking appliance.
Wet Chemical Stored-Pressure Extinguishers
Intended to be used on class B fires. Some types can be used on class A fuels. Contains a specific amount of AFFF with the water to produce a foam solution. It has a air aspirating foam nozzle that aerates the foam solution. Creates a foam covering on the fuel. Not suitable for use on class C, D, or K fuels. Also not to be used on flowing or pressurized fuel. Is corrosive.
Aqueous Film Forming Foam (AFFF) Extinguisher
Developed to replace halogen. Discharged as a rapidly evaporating liquid that leaves no residue. Cool and smoother Class A and B fires and are nonconductive so they can be used on Class C fires.
Clean Agent Extingushers
Extinguishing agent that contains carbon and one or more halogens (fluorine, chlorine, bromine, iodine).
Halogenated Extinguishing Agents