EVT EVT Fire Pump Systems & Water Delivery 2

Question 1

What is the function of the tank fill valve on a fire apparatus water system?

Accepted Answer

Refill the booster tank from the pump while operating

Answer

The tank fill valve routes water from the pump back into the booster tank to refill it while the pump is operating from an external supply.

Question 2

What type of impeller design is most commonly used in single-stage centrifugal fire pumps?

Accepted Answer

Radial flow (centrifugal)

Answer

Single-stage fire pumps most commonly use radial flow centrifugal impellers that accelerate water outward by centrifugal force to generate pressure.

Question 3

What causes water hammer in a fire apparatus discharge system and how should it be prevented?

Accepted Answer

Rapid valve closure; prevent by closing valves slowly

Answer

Water hammer is caused by rapid valve closure creating a pressure surge wave; it is prevented by closing valves slowly to allow gradual deceleration of flow.

Question 4

What is the purpose of a fire pump pressure relief valve (pressure governor)?

Accepted Answer

Prevent excessive discharge pressure to protect hose lines and personnel

Answer

The pressure relief valve or pressure governor limits pump discharge pressure to prevent dangerous overpressure that could burst hose lines or injure personnel.

Question 5

What minimum static pressure should be maintained at the pump intake when pumping from a pressurized hydrant?

Accepted Answer

20 PSI

Answer

A minimum residual intake pressure of 20 PSI should be maintained while drafting from a hydrant to prevent cavitation and ensure adequate supply.

EVT - Certified Emergency Vehicle Technician Practice Test

EVT - Certified Emergency Vehicle Technician Practice Test

EVT EVT Fire Pump Systems & Water Delivery 2