Questions and Correct Detailed Answers
2025 (Verified Answers) With Rationales.
1. What is the minimum pump capacity required for a pumper according to
NFPA 1901?
750 gpm
NFPA 1901 specifies that pumpers must have a minimum pump capacity of 750
gallons per minute (gpm).
2. What is the primary function of a centrifugal pump in fire apparatus?
To convert mechanical energy into kinetic energy to move water
A centrifugal pump uses an impeller to impart velocity to the water, which is then
converted into pressure.
3. What is cavitation in a fire pump?
The formation and collapse of vapor pockets in the pump
Cavitation occurs when water pressure at the pump intake drops below vapor
pressure, causing damage.
4. What is the correct method to prime a centrifugal pump?
Use a positive displacement primer to evacuate air from the pump
Primers are used to remove air and create a vacuum, allowing water to enter the
pump.
5. What does the term "drafting" refer to in fire apparatus operations?
Pulling water from a static source below the pump
Drafting involves drawing water from lakes, ponds, or portable tanks where the
water level is below the pump.
,6. What is the ideal lift height when drafting water at sea level?
10 feet
Though the theoretical lift is around 24 feet, practical operations limit it to 10-12
feet.
7. What component regulates discharge pressure to multiple hoselines?
Pressure governor
The pressure governor automatically adjusts engine throttle to maintain consistent
discharge pressure.
8. What is the purpose of the pump shift control?
To engage the pump from the road transmission to the pump transmission
This control allows the driver to switch from drive mode to pump mode.
9. Which type of hose is most commonly used for drafting?
Hard suction hose
Hard suction hoses are rigid and can withstand negative pressure needed for
drafting.
10. What is the term for water discharged from the pump but not used by
hoselines?
Bypass or recirculation water
This water is sent back to the tank or circulates to prevent overheating.
11. What effect does elevation gain have on pump pressure requirements?
It increases the required pressure by 0.434 psi per foot
For every foot of elevation, the pump must overcome 0.434 psi to maintain flow.
12. What is the typical intake pressure to maintain when operating from a
hydrant?
20 psi
, Maintaining at least 20 psi ensures no damage to the water system or collapse of
the water main.
13. What is the friction loss formula for a single hoseline?
FL = C × Q² × L
Friction loss is calculated using this formula where C is the coefficient, Q is flow in
hundreds of gpm, and L is length in hundreds of feet.
14. When operating multiple lines, how do you prevent one line from losing
pressure when another is shut down?
Use a pressure relief valve
This valve maintains system pressure and prevents water hammer or surges.
15. What is the term for pressure in the system before water is moved?
Static pressure
Static pressure is the pressure in a system at rest.
16. What is the nozzle pressure required for a smooth bore handline?
50 psi
Smooth bore nozzles require 50 psi for proper stream formation.
17. What is a master stream appliance?
A device that delivers large volumes of water, usually over 350 gpm
These are mounted or portable units used for defensive operations.
18. What pump stage provides the highest pressure at lower flows?
Series (pressure) stage
In series mode, water passes through two impellers, increasing pressure.
19. What condition can occur if pump discharge pressure exceeds hose
capacity?