Fire Extinguishers Flashcards
Portable fire extinguisher overview
a. Most common fire protection appliance.
b. Intended for use on small fires in the incipient or early growth stage.
c. Multiple uses and sizes available.
Portable fire extinguisher classifications
a. They are designed for the type of fire they are designed to extinguish
b. 5 total classes
c. Must determine what is burning in order to select the class correctly.
Class A
Class B
Class C
Class D
Class K
Class A
– ordinary combustibles
- Textiles
- Paper
- Plastics
- Rubber
- Wood
- Fuels that can easily be extinguished with water-based agents
Class B
flammable and combustible liquids
- Alcohol
- Gasoline
- Lubricating oils
- Liquefied Petroleum Gas (LPG)
- Agents used to extinguish class B fires are :
a. Carbon dioxide
b. Dry Chem
c. Class B foam
Class C
energized electrical
- Class C extinguishing agents will not conduct electricity
a. Carbon Dioxide
b. Halon extinguishing agents - Once the power source has been disconnected or turned off, treat as class A or class B fire
Class D
combustible metals
- Lithium
- Magnesium
- Potassium
- Sodium
- Dry powder extinguishers work best for these types of fires
- Places where you will find magnesium
a. Wheels and transmission equipment
b. Some metal box springs
c. Identifiable by the bright white light emitted during combustion
Class K
kitchen grease laden equipment
- Vegetable oils
- Animal fats
- Oils that burn at extremely high temperatures
- Wet chemical systems and portable extinguishers are used to control and extinguish class K fires.
Types of portable fire extinguishers and how they work.
a. Fire extinguishers are organized by the type of extinguishing agent as well as the method used to expel the contents.
b. Extinguishing agents use at least one of the following methods to extinguish a fire
i. Smothering
ii. Cooling
iii. Chain breaking
iv. Saponification
Types of extinguishing agents
i. Water
ii. Carbon dioxide
iii. Foam (AFFF, FFFP, class A)
iv. Clean agents (halogenated)
v. Dry chem (sodium bicarbonate, potassium bicarbonate, ammonium phosphate, potassium chloride)
vi. Wet chemical (Potassium Acetate)
vii. Dry powder
Methods of expelling fire extinguisher contents
i. Manual pump
ii. Stored pressure
iii. Pressure cartridge
Pump water type
- Ground cover fires or small class A
2. Commonly used for wildland
Stored pressure water
- Also called air pressure (APW) or pressure water (PW can)
- Useful for all types of small class A fires
- Water stored in a tank along with nitrogen.
- Can add class foam concentrate to reduce surface tension, making the water more effective.
- Straight stream with range of 30-40ft.
Water mist stored pressure
- Similar to stored pressure.
- Uses deionized water as agent.
- Nozzle produces fine spray instead of solid stream.
Wet Chemical stored pressure
- Similar in appearance to PW cans.
- However, are intended for use on class K fires.
- Contains special potassium based lo pH surface agent.
- Combines with oils to form a soapy surface known as saponification.
AFFF
Aqueous film forming foam
- Class B extinguishing agent
- Suppresses vapors on flammable liquids spills
- Air aspirating foam nozzle.
- Stored pressure form air or nitrogen.
- Do not spray directly on the liquid spill, rain the agent down or deflect off of nearby object.