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
Found on both handheld and wheeled units. Most effective on Class B and C fires. Limited reach due to being discharged as a gas. Displaces O2 and smothers the fire. No film formed and no cooling action.
Carbon Dioxide (CO2) Extinguishers
A wheeled CO2 extinguisher usually weighs how much?
50-100 Pounds
Name two types of dry chem extinguishers.
Regular B:C rated and Multipurpose or A:B:C rated
Name 5 types of chemicals commonly used in dry chem extinguishers.
Sodium Bicarbonate, Potassium Bicarbonate, Urea-Potassium Bicarbonate, Potassium Chloride, Monoammonium Phosphate.
Most dry chem extinguishers are mildly ……… to all surfaces.
corrosive
Are dry powder and dry chemical extinguishers the same?
NO. Dry powder are only for type D fires.
Name the two design for a handheld dry chem extinguisher.
Cartridge and Stored pressure. Stored pressure is keep at approx 200 psi. In both types nitrogen or CO2 are the gases used.
Wheeled dry chem extinguishers have two tanks, what do they store?
One tank for the dry chem, the other tank has pressurized gas.
Can be a handheld or wheeled unit. Must be applied in sufficient amounts to create a smothering blanket. Extinguishing agent is specific to the type of metal burning. Continual add until the fire is out.
Dry Powder Extingushers
Class A and B extinguishers are also rated according to their performance capability, which is represented by what?
A number
Class A fire extinguishers are rated from what through what?
1-A through 40-A
If a 1-A extinguisher discharges 1 1/4 gallons of water, what does a 2-A discharge?
2 1/2 gallons or double of the 1-A
Class B fire extinguishers are rated from what to what?
1-B through 640-B
The class B extinguisher rating is based on what?
The approximate area of a flammable liquid fire that a non-expert operator could extinguisher using one full extinguisher. Each numerical rating = 1 square foot
A class C rating confirms what?
That the extinguishing agent will not conduct electricity.
Class D ratings vary with each combustible metal. List the criteria tested.
Reactions between the metal and the agent. Toxicity of the agent. Toxicity from the fumes produced and the products of combustion. Time to allow metal to burn compared to time to extinguish the metal.
If a class D rating is given to a extinguisher it will include application instructions on what part of the extinguisher?
The faceplate
Class K ratings are based on the ability to cause saponification, extinguishing a fire in a deep fryer with cooking oils that has a surface area of what?
2.25 square feet.
Name the three most common types of combination rating fire extinguishers.
Class A-B-C, Class A-B, and Class B-C.
Portable fire extinguishers are identified in two ways, what are those ways?
Use of geometric shapes, specific colors, and class letter. Pictographs of what type of fire the extinguisher is used for.
Class A letter symbol
A in green triangle
Class B letter symbol
B in red square
Class C letter symbol
C in blue circle
Class D letter symbol
D in yellow star
Class K letter symbol
K in black hexagon.
Do not use dry chemical extinguishers in what areas?
Areas with highly sensitive computer equipment. Due to its corrosive nature.
Should full PPE with resp protection be worn when using a extinguisher?
Yes
What four components of the extinguisher should be checked prior to its use?
External condition (no apparent damage). Hose/Nozzle (In place). Weight (feels as though it contains agent). Pressure Gauge ( in operable range).
When using a extinguisher what does PASS stand for?
P= pull the pin. A= Aim the nozzle at the base of the fire. S= Squeeze the handles together to release the agent. S= Sweep the nozzle back and forth to cover the burning material.
How should empty extinguishers be laid?
On their side.
Require that portable fire extinguishers be inspected at least once each year to ensure that they are accessible and operable.
NFPA 10 and most fire and life safety codes.
Name three factors that should be check when determining the value of a fire extinguisher.
- Serviceability 2. Accessibility 3. Simplicity of Operation
When should fire extinguishers on apparatus be checked.?
At the beginning of the shift or at least once a week.
If a extinguisher is found to be deficient in weight by …….., it should be removed from service and replaced.
10%
How often should dry chem extinguisher’s be shaken to loosen agent and prevent it from settling?
Monthly
How often should dry chem agent from a extinguisher be removed and replaced?
Every 6 years.
