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Questions and Answers
What is the primary function of water when used as an extinguishing agent in fire service hydraulics?
What is the primary function of water when used as an extinguishing agent in fire service hydraulics?
- To displace oxygen and smother the fire.
- To cool the burning material and reduce its temperature below ignition point. (correct)
- To chemically react with the burning material and neutralize it.
- To create a barrier between the fuel and the ignition source.
Which of the following best describes the latent heat of vaporization?
Which of the following best describes the latent heat of vaporization?
- The heat absorbed when a substance changes from solid to liquid.
- The heat required to change a solid directly into a gas.
- The heat required to raise the temperature of a substance by one degree.
- The amount of heat absorbed when a liquid changes into a gas. (correct)
What does the British Thermal Unit (BTU) measure?
What does the British Thermal Unit (BTU) measure?
- The rate at which water evaporates at different temperatures.
- The volume of water required to extinguish a fire.
- The amount of heat to raise the temperature of 1 lb of water by 1 degree Fahrenheit. (correct)
- The pressure exerted by water at various depths.
How much does 212°F water vapor expand?
How much does 212°F water vapor expand?
How many pounds does one cubic foot of water weigh?
How many pounds does one cubic foot of water weigh?
How many gallons are in one cubic foot of water?
How many gallons are in one cubic foot of water?
How many cubic inches are in one gallon of water?
How many cubic inches are in one gallon of water?
How much does a 1 sq. inch column of water that is 1 foot deep weigh?
How much does a 1 sq. inch column of water that is 1 foot deep weigh?
What is the relationship between the depth of a liquid in an open container and the downward pressure it exerts?
What is the relationship between the depth of a liquid in an open container and the downward pressure it exerts?
Which factor does NOT influence the downward pressure of a liquid on the bottom of an open container?
Which factor does NOT influence the downward pressure of a liquid on the bottom of an open container?
What is the typical nozzle pressure for a smoothbore handline?
What is the typical nozzle pressure for a smoothbore handline?
What is the typical nozzle pressure for a fog nozzle handline?
What is the typical nozzle pressure for a fog nozzle handline?
What is the typical nozzle pressure for a smoothbore master stream?
What is the typical nozzle pressure for a smoothbore master stream?
Which characteristic is essential for a good solid stream?
Which characteristic is essential for a good solid stream?
A fire stream is considered effective if 9/10 of its volume stays within a 15-inch diameter circle and 3/4 stays within a 10-inch circle where?
A fire stream is considered effective if 9/10 of its volume stays within a 15-inch diameter circle and 3/4 stays within a 10-inch circle where?
What determines the named height of a stream?
What determines the named height of a stream?
When describing the qualities of a good fire stream, what characteristic describes its ability to reach a ceiling with enough force to splatter well?
When describing the qualities of a good fire stream, what characteristic describes its ability to reach a ceiling with enough force to splatter well?
According to the provided information, which factor directly extinguishes a fire?
According to the provided information, which factor directly extinguishes a fire?
What is the definition of force?
What is the definition of force?
When a substance passes between solid and liquid states, what is this describing?
When a substance passes between solid and liquid states, what is this describing?
What do water's primary use to extinguish fires?
What do water's primary use to extinguish fires?
What pressure is a smoothbore master stream?
What pressure is a smoothbore master stream?
What pressure is a fog nozzle handline?
What pressure is a fog nozzle handline?
What is the listed pressure of a smoothbore handline?
What is the listed pressure of a smoothbore handline?
What is latent heat of vaporization?
What is latent heat of vaporization?
Why is it important for a fire stream to maintain its continuity?
Why is it important for a fire stream to maintain its continuity?
What occurs when fire stream shoots 9/10 of the whole volume inside a 15 inch diameter circle and 3/4 of it's volume into a 10 inch circle?
What occurs when fire stream shoots 9/10 of the whole volume inside a 15 inch diameter circle and 3/4 of it's volume into a 10 inch circle?
Which characteristic is required for a stream is stiff enough to attain under fair conditions?
Which characteristic is required for a stream is stiff enough to attain under fair conditions?
A firestream will enter a room through a window and what will it strike?
A firestream will enter a room through a window and what will it strike?
What amount of water will cool the fire?
What amount of water will cool the fire?
What is the weight of 1 gallon of water?
What is the weight of 1 gallon of water?
What weight of water exerts pressure of .434 lbs?
What weight of water exerts pressure of .434 lbs?
What absorbs or releases heat passing between solid and liquid states?
What absorbs or releases heat passing between solid and liquid states?
What is the definition of latent heat of fusion?
What is the definition of latent heat of fusion?
Flashcards
Water's role in fire suppression?
Water's role in fire suppression?
Water's primary function is to absorb heat from burning materials, thus stopping the combustion process.
Latent Heat of Fusion
Latent Heat of Fusion
The heat absorbed or released when a substance changes between solid and liquid states.
Latent Heat of Vaporization
Latent Heat of Vaporization
The heat absorbed when a liquid changes into a gas.
British Thermal Unit (BTU)
British Thermal Unit (BTU)
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Expansion of 212°F water vapor
Expansion of 212°F water vapor
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Expansion of 500°F water vapor
Expansion of 500°F water vapor
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Expansion of 1,200°F water vapor
Expansion of 1,200°F water vapor
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Weight of water per cubic foot
Weight of water per cubic foot
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Weight of water per gallon
Weight of water per gallon
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Cubic Foot to Gallons (water)
Cubic Foot to Gallons (water)
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Gallon to Cubic Inches (water)
Gallon to Cubic Inches (water)
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Weight of 1 sq. in. of water (1 ft deep)
Weight of 1 sq. in. of water (1 ft deep)
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Force (definition)
Force (definition)
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Pressure vs. Depth in Open Container
Pressure vs. Depth in Open Container
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Pressure vs. Container Shape/Size
Pressure vs. Container Shape/Size
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Smoothbore Handline Pressure
Smoothbore Handline Pressure
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Fog Nozzle Handline Pressure
Fog Nozzle Handline Pressure
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Smoothbore Master Stream Pressure
Smoothbore Master Stream Pressure
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Good Solid Stream
Good Solid Stream
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Solid Stream: Volume and Coverage
Solid Stream: Volume and Coverage
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Solid Stream: Stiffness
Solid Stream: Stiffness
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Solid Stream: Ceiling Impact
Solid Stream: Ceiling Impact
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Fire Extinguishment Factor
Fire Extinguishment Factor
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Study Notes
Water as an extinguishing Agent
- Water primarily cools burning material to stop it from burning.
- Latent heat of fusion: when a substance transitions between solid and liquid states, it absorbs or releases heat.
- Latent heat of vaporization: heat is released when a liquid turns into a gas.
- British Thermal Unit (BTU) is the amount of heat needed to raise the temperature of 1 pound of water by 1 degree Fahrenheit.
- Water vapor at 212°F expands 1700 times.
- Water vapor at 500°F expands 2400 times.
- Water vapor at 1200°F expands 4200 times.
- Water weighs 62.5 lbs per cubic foot.
- Water weighs 8.35 lbs per gallon.
- 1 cubic foot of water equals 7.48 gallons.
- 1 gallon of water equals 231 cubic inches.
- A 1 sq. ft. area of water that is 1 ft. deep weighs 0.434 lbs.
- Force is the amount of energy applied to a given point.
- Downward pressure in an open container is proportional to the liquid's depth.
- Down pressure at the bottom of an open container is independent of the container's shape or size.
Nozzle Pressure
- Smoothbore handline pressure is 50 psi.
- Fog nozzle handline pressure is 100 psi.
- Smoothbore master stream pressure is 80 psi.
Good Solid Stream Characteristics
- A stream that maintains continuity without breaking into showers or spray.
- A stream that directs 9/10 of its total volume within a 15-inch diameter circle.
- A stream that directs ¾ of its volume into a 10-inch circle at its breakover point.
- A stream should be stiff enough to reach the desired height or distance, even in a breeze.
- A stream should enter a room through a window and hit the ceiling with enough force to splatter without wind.
- Fire extinguishment depends on the quantity of water (in gpm) cooling the fire, not the stream's pressure.
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