Fire Extinguishers

Question 1

Portable fire extinguisher overview

Answer 1

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.

Question 2

Portable fire extinguisher classifications

Answer 2

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

Question 3

Class A

Answer 3

– ordinary combustibles

1. Textiles
2. Paper
3. Plastics
4. Rubber
5. Wood
6. Fuels that can easily be extinguished with water-based agents

Question 4

Class B

Answer 4

flammable and combustible liquids

1. Alcohol
2. Gasoline
3. Lubricating oils
4. Liquefied Petroleum Gas (LPG)
5. Agents used to extinguish class B fires are :
   a. Carbon dioxide
   b. Dry Chem
   c. Class B foam

Question 5

Class C

Answer 5

energized electrical

1. Class C extinguishing agents will not conduct electricity
   a. Carbon Dioxide
   b. Halon extinguishing agents
2. Once the power source has been disconnected or turned off, treat as class A or class B fire

Question 6

Class D

Answer 6

combustible metals

1. Lithium
2. Magnesium
3. Potassium
4. Sodium
5. Dry powder extinguishers work best for these types of fires
6. 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

Question 7

Class K

Answer 7

kitchen grease laden equipment

1. Vegetable oils
2. Animal fats
3. Oils that burn at extremely high temperatures
4. Wet chemical systems and portable extinguishers are used to control and extinguish class K fires.

Question 8

Types of portable fire extinguishers and how they work.

Answer 8

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

Question 9

Types of extinguishing agents

Answer 9

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

Question 10

Methods of expelling fire extinguisher contents

Answer 10

i. Manual pump
ii. Stored pressure
iii. Pressure cartridge

Question 11

Pump water type

Answer 11

1. Ground cover fires or small class A

2. Commonly used for wildland

Question 12

Stored pressure water

Answer 12

1. Also called air pressure (APW) or pressure water (PW can)
2. Useful for all types of small class A fires
3. Water stored in a tank along with nitrogen.
4. Can add class foam concentrate to reduce surface tension, making the water more effective.
5. Straight stream with range of 30-40ft.

Question 13

Water mist stored pressure

Answer 13

1. Similar to stored pressure.
2. Uses deionized water as agent.
3. Nozzle produces fine spray instead of solid stream.

Question 14

Wet Chemical stored pressure

Answer 14

1. Similar in appearance to PW cans.
2. However, are intended for use on class K fires.
3. Contains special potassium based lo pH surface agent.
4. Combines with oils to form a soapy surface known as saponification.

Question 15

AFFF

Answer 15

Aqueous film forming foam

1. Class B extinguishing agent
2. Suppresses vapors on flammable liquids spills
3. Air aspirating foam nozzle.
4. Stored pressure form air or nitrogen.
5. Do not spray directly on the liquid spill, rain the agent down or deflect off of nearby object.

Question 16

Clean agent

Answer 16

1. Designed to replace halogenated extinguishing agents
2. Discharged as a rapidly evaporating liquid that leaves no residue.
3. 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)

Question 17

Carbon Dioxie

Answer 17

1. Both handheld and wheeled units
2. Most effective on class B and class C
3. Stored under its own pressure as a liquefied gas and converts into a gas when discharged.
4. Discharged through plastic/rubber horn
5. Works by displacing the oxygen and smothering fire
6. Very limited reach of 3-8ft due to being discharged as a gas

Question 18

Dry Chemical

Answer 18

1. Not the same as dry powder
2. Designed for use in Class A, B, and C fires
3. Most commonly used fire extinguisher used today
4. Commonly used dry chemicals
   a. Sodium bicarbonate
   b. Potassium bicarbonate
   c. Urea-potassium bicarbonate
   d. Potassium chloride
   e. Monammonium phosphate
5. 2 types:
   a. Regular B:C rated
   b. Multipurpose A:B:C rated
6. Dry chemicals are non-toxic, however, the cloud they create may reduce visibility and create respiratory problems.
7. Mildly corrosive to all surfaces
8. Can either be cartridge operated or stored pressure
9. A constant pressure of 200psi is maintained in the agent storage tank
10. Both will utilize either nitrogen or carbon dioxide as the pressurized gas

Question 19

Dry Powder

Answer 19

1. Designed for class D fires
2. No single agent will control or extinguish all combustible metal fires
3. Some are designed for several types of metal and others are for one specific metal only.
4. Some are powdered agents that are applied with an extinguisher, while others are applied with a shovel or scoop.
5. Designed to create a smothering blanket over the metal.
6. Apply gently to avoid breaking the crust that forms over the metal.

Question 20

Fire extinguisher rating

Answer 20

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

Question 21

Class A fire extinguisher rating

Answer 21

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)

Question 22

Class B fire extinguisher rating

Answer 22

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.

Question 23

Class C fire extinguisher rating

Answer 23

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

Question 24

Class D fire extinguisher rating

Answer 24

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.

Question 25

Class K fire extinguisher rating

Answer 25

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

Question 26

Multiple marking fire extinguisher rating

Answer 26

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

Question 27

How to use a fire extinguisher

Answer 27

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

Question 28

NFPA for fire extingishers inspection

Answer 28

NFPA 10

Question 29

Inspection of fire extinguishers

Answer 29

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?

Question 30

Care of fire extinguishers

Answer 30

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

Question 31

Maintinance of fire extinguishers

Answer 31

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.

Question 32

Summary of fire extinguishers

Answer 32

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