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.
Clean agent
- Designed to replace halogenated extinguishing agents
- Discharged as a rapidly evaporating liquid that leaves no residue.
- Can be used for Class A, B or C fires
a. FE 36 hexaflouropropane
b. Hydrochloroflourocarbon (HCCF)
c. Hydrofluorocarbon (HFC)
d. Perfluorocarbon (PFC)
e. Flouroiodiocarbon (FIC)
Carbon Dioxie
- Both handheld and wheeled units
- Most effective on class B and class C
- Stored under its own pressure as a liquefied gas and converts into a gas when discharged.
- Discharged through plastic/rubber horn
- Works by displacing the oxygen and smothering fire
- Very limited reach of 3-8ft due to being discharged as a gas
Dry Chemical
- Not the same as dry powder
- Designed for use in Class A, B, and C fires
- Most commonly used fire extinguisher used today
- Commonly used dry chemicals
a. Sodium bicarbonate
b. Potassium bicarbonate
c. Urea-potassium bicarbonate
d. Potassium chloride
e. Monammonium phosphate - 2 types:
a. Regular B:C rated
b. Multipurpose A:B:C rated - Dry chemicals are non-toxic, however, the cloud they create may reduce visibility and create respiratory problems.
- Mildly corrosive to all surfaces
- Can either be cartridge operated or stored pressure
- A constant pressure of 200psi is maintained in the agent storage tank
- Both will utilize either nitrogen or carbon dioxide as the pressurized gas
Dry Powder
- Designed for class D fires
- No single agent will control or extinguish all combustible metal fires
- Some are designed for several types of metal and others are for one specific metal only.
- Some are powdered agents that are applied with an extinguisher, while others are applied with a shovel or scoop.
- Designed to create a smothering blanket over the metal.
- Apply gently to avoid breaking the crust that forms over the metal.
Fire extinguisher rating
a. Classified according t the types of fire for which they are intended
b. Class A and B are rated to performance capacity
c. Alphanumeric
i. Alpha (Class A, B, C, D, or K)
ii. Numeric (Performance)
iii. Ratings are determined by Underwriters Laboratory
Class A fire extinguisher rating
i. Rated from 1-A to 40-A
ii. For 1-A, 1.25 gallons is required
iii. For 2-A, 2.5 gallons is required (TFD)
Class B fire extinguisher rating
i. Ratings from 1-B through 640-B
ii. Rating based on the approximate square foot of flammable liquid a non-expert can extinguish with one full extinguisher.
iii. A non-expert is expected to extinguish 1 sqft for each numerical rating or value of the extinguisher.
Class C fire extinguisher rating
i. There are no capability test specifically conducted for C ratings
ii. Extinguisher for class C fires receive that letter rating because Class C are essentially an A or B fire involving electrical equipment
iii. A class C rating confirms that the agent used will not conduct electricity
Class D fire extinguisher rating
i. Testing varies depending on the metal being tested
ii. No numerical rating is given
iii. Instructions will be on the faceplate of the extinguisher.
Class K fire extinguisher rating
i. Capable of saponifying vegetable, peanut, and canola oil
ii. Wet chemical agents containing an alkaline mixture
1. Potassium acetate
2. Potassium carbonate
3. Potassium citrate
iii. Must be able to extinguish a deep fryer containing the light oils with a surface area of 2.25 sqft to meet the minimum criteria for a class K
Multiple marking fire extinguisher rating
i. Identified by a combination of letters, A, B and or C
ii. Most common types
1. ABC
2. AB
3. BC
iii. A 4-A 20B:C should
1. Extinguish a class A fire that is 4 times larger than a 1-A
2. Approximately 20 times as much of a Class B fire as a class 1-B extinguisher
3. Extinguish a deep-layer flammable liquid fire of 20sqft
4. Non-conductive
How to use a fire extinguisher
a. Inspect before use
i. External condition
ii. Hose/nozzle
iii. Weight
iv. Pressure gauge
v. Approach from windward side
vi. Use PASS
1. Pull
2. Aim
3. Squeeze
4. Sweep
NFPA for fire extingishers inspection
NFPA 10
Inspection of fire extinguishers
a. NFPA 10 requires extinguishers to be inspect at least once a year
b. Check inspection tag for last inspection
c. Check pressure gauge, weighing, and inspecting agent level.
i. Recharge if deficient in weight by 10%
ii. Weight will be stamped on neck
d. Inspect the discharge nozzles or horn
e. Check the hose for cracks or damage
f. Does the shell have physical damage?
g. Are the operating instructions legible?
h. Is it in the proper location?
Care of fire extinguishers
a. Shake dry chemical extinguishers monthly to loosen the agent and prevent it from settling
b. Clean after each use
c. Always recharge or refill fire extinguishers regardless of how much is used
d. Store securely in apparatus
e. No drop!
f. Do not remove safety pin until ready to use
Maintinance of fire extinguishers
a. Because they are pressurized, they must be hydrostatically tested.
b. TFD hydrostatically tests extinguishers every 5 years
c. Test results must be affixed to extinguisher shell.
Summary of fire extinguishers
a. Understanding classification, rating and use for extinguishers ensures that:
i. You can use a portable extinguisher
ii. You can instruct the business and residential communities on the appropriate use.
iii. Demonstrate professionalism in the fire service
