Firefighting Flashcards
What is the definition of fire?
The chemical reaction that occurs when a material unites with oxygen so rapidly that it produces heat and light energy in the form of flame.
What are the four elements of the fire tetrahedron?
- Heat
- Oxygen
- Fuel
- Chemical Chain Reaction
What percentage of oxygen is typically found in normal air?
About 21 percent
What is the minimum oxygen percentage required for fire?
About 16 percent
What types of materials can be considered fuel?
- Solid
- Liquid
- Gas
What must happen to most solids and liquids before they will burn?
They must become a vapour or gas.
What is the role of heat in the fire tetrahedron?
Heat is the energy necessary to increase the temperature of the fuel to a point where sufficient vapours are given off for ignition to occur.
What is a chemical chain reaction in the context of fire?
Oxidation that can occur when oxygen, fuel, and heat are present in the proper conditions and proportions.
True or False: Fire can be prevented or extinguished by removing any one element of the fire tetrahedron.
True
Fill in the blank: Fire occurs when rapid oxidation, or ________, takes place.
[combustion]
What are the primary classifications of underground fires?
The primary classifications are:
* Diesel-powered equipment
* Electrical
* Burning and welding
* Friction
* Spontaneous combustion
* Smoking or open flame
These categories reflect the sources of ignition for underground fires.
Which type of equipment is responsible for almost 70 percent of underground fires?
Diesel-powered equipment
Diesel equipment is the leading cause of underground fires based on recent occurrence data.
What percentage of underground fires are attributed to electrical equipment and burning/welding combined?
20 percent
This percentage indicates the significant role of electrical sources and welding activities in fire incidents.
Fill in the blank: The category of fire caused by the use of compressed gases and electrical welding is known as _______.
[Burning and welding]
This category includes any activities that involve heat generation through welding processes.
True or False: Spontaneous combustion can occur due to the accumulation of combustible materials.
True
Spontaneous combustion is a fire risk associated with certain materials, such as sulphide ores and tailings.
What factors contribute to friction-related fires in underground environments?
Factors include:
* Conveyor belts
* Drive units
* Brakes and clutches
* Gear boxes
These mechanical components can generate heat and sparks, leading to fires.
Fill in the blank: Smoking or open flame fires can be either _______ or accidental.
[deliberate]
This highlights the risk associated with human activities in underground settings.
What are the four classes of fires?
Class A, Class B, Class C, Class D
Class D fires involve combustible metals.
What materials are involved in Class A fires?
Ordinary combustible materials such as wood, cloth, paper, rubber, and many plastics
These materials require cooling effects of water or certain dry chemicals for suppression.
What is the primary method for extinguishing Class A fires?
Water or water solutions, or certain dry chemicals that retard combustion
The cooling effect of water is essential for Class A fires.
What distinguishes Class B fires from other classes?
They occur in the vapour-air mixture over the surface of flammable liquids
Class B fires are related to combustion in vapours or flammable liquids.
What are some extinguishing agents for Class B fires?
Dry chemical, foam, vapourizing liquids, carbon dioxide, or water fog
The choice of agent depends on the circumstances of the fire.
What is a key safety consideration for Class C fires?
Use of electrically non-conductive extinguishing agents
This is to ensure safety for the operator of the extinguisher.
Which extinguishing agents are suitable for Class C fires?
Dry chemical and carbon dioxide
Foam, water, and water-type agents conduct electricity and can be dangerous.
What is an exception for using water on Class C fires?
Water mist stored-pressure extinguishers with non-ionized water
These are approved and safe to use on electrical fires.
True or False: Class A or B extinguishers can be used on Class C fires when electric power is disconnected.
True
It is safe to use Class A or B extinguishers after disconnecting power.
What is the main characteristic of Class D fires?
Involves combustible metals
Specific methods and agents are required for Class D fires.
What are the four elements of the fire tetrahedron?
Heat, fuel, oxygen, and chain reaction
The fire tetrahedron represents the four components necessary for fire to occur.
What is the most common method of extinguishing fire?
Cooling the burning material with water
This method lowers the temperature of the fuel below its combustion point.
How does cooling with water extinguish fire?
It lowers the temperature of the fuel to below its combustion point
Enough water must be applied to absorb the heat generated by combustion.
Why is cooling with water ineffective on gas and most liquid fires?
Because it cannot effectively lower the temperature of the fuel
Water may not mix well with certain fuels, making it ineffective.
What does fuel removal involve?
Stopping the flow of gaseous or liquid fuel or removing solid fuel
Allowing a fire to burn until all fuel is consumed is also a method of fuel removal.
What is oxygen starvation in the context of fire extinguishing?
Removing or reducing the oxygen available for combustion
It can occur by displacing oxygen with an inert gas or covering the fire.
What is an example of an inert gas used for oxygen starvation?
Carbon dioxide
This gas can displace oxygen, helping to extinguish the fire.
What are chain reaction inhibitors?
Extinguishing agents that interrupt the chemical reaction of fire
Halon is a commonly known chain breaker, effective on various types of fires.
Which types of fires are chain reaction inhibitors particularly effective on?
Gas, liquid, and metal fires
These agents can disrupt the ongoing chemical reactions that sustain the fire.
What is a common combination of extinguishing principles used in firefighting?
Cooling with water and using foam to smother the fire
Cooling can create steam that helps starve the fire of oxygen.
Fill in the blank: Fire can be extinguished by removing any one element of the _______.
tetrahedron
The tetrahedron represents the four essential components of fire.
What type of foam do foam extinguishers, Type AB, use?
AFFF or aqueous film-forming foam
Foam extinguishers, Type AB, are effective on which classes of fires?
Class A and B fires
True or False: Foam extinguishers can be used on electrical fires.
False
What is the extinguishing agent in carbon dioxide extinguishers, Type BC?
Carbon dioxide
Carbon dioxide extinguishers are safe to use on which classes of fires?
Class A, B, and C fires
What is the primary use of wet chemical extinguishers, Type AK?
Class K, cooking oil, fires
What is the extinguishing agent in wet chemical extinguishers?
Potassium acetate
List the general procedures when using a fire extinguisher.
- Check extinguisher type
- Pull the pin
- Test range with a short burst
- Approach within range
- Aim low at the base
- Squeeze the lever
- Sweep from side to side
What does the mnemonic ‘PASS’ stand for in fire extinguisher use?
- Pull the pin
- Aim at the base
- Squeeze the lever
- Sweep from side to side
Why should a second fire extinguisher be available during a fire?
To support the initial attack and allow the initial firefighter to back away
What action should be taken if the fire does not go out after using the extinguisher?
Immediately leave the area
What should you do when leaving an active fire area?
Pay attention to the fire and never turn your back
What should you watch for after extinguishing a fire?
Re-ignition
Fill in the blank: The extinguishing agent in carbon dioxide extinguishers is _______.
carbon dioxide
True or False: Carbon dioxide extinguishers leave a chemical residue.
False
What could carbon dioxide extinguishers potentially damage?
Sensitive electronic equipment
What are fire hoses and nozzles classified based on?
Flow capacity
Nozzles are usually adjustable to create different water streams.
What is a standard length for fire hoses?
15 metres (50 ft)
Shorter lengths are also available.
What is the first step in using a hose and nozzle in firefighting?
Check the standpipe or water source for adequate water pressure
Fill in the blank: The procedure for using a hose and nozzle includes deploying the _______.
full length of the hose
What is water fog used for in firefighting?
Class A and B fires
Describe water fog.
Composed of fine particles of water expelled through a special high-pressure nozzle
What happens when water fog hits the fire?
Water is turned to steam, reducing heat and cutting off oxygen
True or False: Water fog causes more water damage than straight stream nozzles.
False
What is a benefit of using water fog for rescue teams?
Acts as a heat barrier
What are the types of streams that nozzles can create?
Solid, broken, fog
What is the procedure to charge a hose?
Test the charged hose for water pressure
Fill in the blank: Hose and nozzle are also used in several types of _______ applications.
foam
What is fire?
Fire is the chemical reaction that occurs when a material unites with oxygen so rapidly that it produces heat and light energy in the form of flame.
What are the four elements of the fire tetrahedron?
- Oxygen
- Fuel
- Heat
- Chemical chain reaction
True or False: Removing any element from the fire tetrahedron can prevent or extinguish a fire.
True
What are the classifications of fires based on the fuel that feeds them?
- Class A - wood, cloth, paper, rubber, and many plastics
- Class B - flammable liquids such as greases, gasoline, and lubricating oils
- Class C - live electrical equipment
- Class D - combustible metals, such as magnesium
- Class K - cooking oils
What type of fire extinguisher is most effective on Class A fires?
Type A - Water extinguishers
Fill in the blank: Type ______ extinguishers are multi-purpose dry chemical extinguishers.
ABC
What type of extinguishers are used for Class B fires?
- Type BC - Dry chemical extinguishers
- Type BC - Carbon dioxide extinguishers
What is the function of foam in firefighting?
Foam works by converting heat to steam and cutting off fuel from oxygen.
What type of foam is effective for Class A and B fires?
AFFF or low expansion foams
What type of foam works best on three-dimensional fires?
High expansion foam
What standard firefighting equipment is used regardless of the method?
A fire hose and nozzle
Fill in the blank: A fire hose and nozzle can use water streams, water fog, or _______ agents.
foaming
