Free EVT F8 practice test: Fire Apparatus Hydraulic Systems

Free EVT F8 practice test: 10 questions

Questions from our F8 bank, written to EVTCC's learning objectives and the 2024 NFPA 1900 and 1910. Tap an answer to see if you're right and why, or switch to Timed for the real test's pace. Every answer is below each question.

1. According to Pascal's law, pressure applied to a confined hydraulic fluid is:

   ATransmitted equally in all directions BGreatest only at the pump outlet CReduced as it travels through the hose DTransmitted only in the direction of flow
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   Answer: A. Transmitted equally in all directions

   Pascal's law states that pressure on a confined fluid is transmitted undiminished and equally in every direction against all boundaries of its container.

   • B: Pressure in a confined fluid is equal throughout, not concentrated at the outlet.
   • C: In a static confined fluid, pressure is not lost to travel distance.
   • D: Pressure acts on all container surfaces, not just along the flow path.

2. A hydraulic cylinder has a piston area of 4 square inches and the system supplies 1,000 psi. How much force can the cylinder produce?

   A250 lb B1,000 lb C4,000 lb D40,000 lb
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   Answer: C. 4,000 lb

   Force equals pressure times area, so 1,000 psi x 4 in² = 4,000 lb of force.

   • A: That divides pressure by area, which is incorrect.
   • B: That ignores the piston area entirely.
   • D: That uses ten times the actual piston area.

3. In a hydraulic system, which factor primarily determines how fast an actuator moves?

   AThe rate of fluid flow (GPM) BThe system pressure (psi) CThe fluid color DThe reservoir capacity
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   Answer: A. The rate of fluid flow (GPM)

   Flow rate (volume per unit time) determines how fast an actuator moves; pressure determines the force available.

   • B: Pressure sets the available force, not the speed.
   • C: Fluid color has no bearing on actuator speed.
   • D: Reservoir capacity does not set actuator speed.

4. Two identical cylinders move at the same speed, but one must lift a heavier load. What must be increased to lift the heavier load?

   AFluid flow (GPM) BSystem pressure (psi) CReservoir size DHose length
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   Answer: B. System pressure (psi)

   Pressure determines the force a cylinder can produce, so a heavier load needs higher pressure while flow controls speed.

   • A: Flow controls speed, which is being held constant here.
   • C: Reservoir size does not affect lifting force.
   • D: Hose length does not determine force output.

5. Two technicians discuss hydraulic pumps. Technician A says a gear pump is a fixed-displacement pump. Technician B says piston pumps are generally used where higher operating pressures are needed. Who is correct?

   ATechnician A only BTechnician B only CBoth Technicians A and B DNeither Technician
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   Answer: C. Both Technicians A and B

   Gear pumps are simple, fixed-displacement units, while piston pumps efficiently handle higher operating pressures; both statements are correct.

   • A: Technician A is correct, but so is Technician B.
   • B: Technician B is correct, but so is Technician A.
   • D: Both statements are accurate, so 'neither' is wrong.

6. Which pump type is most commonly used in mobile hydraulics for its simplicity and rugged fixed-displacement design?

   AGear pump BVariable-displacement piston pump CCentrifugal pump DTurbine pump
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   Answer: A. Gear pump

   Gear pumps are simple, durable, fixed-displacement positive-displacement pumps widely used on apparatus hydraulic systems.

   • B: A variable piston pump is more complex and variable-displacement.
   • C: A centrifugal pump is a non-positive-displacement type not typical for these circuits.
   • D: A turbine pump is not a standard hydraulic power pump here.

7. A double-acting hydraulic cylinder differs from a single-acting cylinder in that it:

   AIs powered hydraulically in both the extend and retract directions BCan only be powered hydraulically in the extend direction CIs built with no sealing rings on the piston itself DCannot be used on an aerial device's hoist circuit
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   Answer: A. Is powered hydraulically in both the extend and retract directions

   A double-acting cylinder uses hydraulic pressure to both extend and retract; a single-acting cylinder is powered one way and returns by gravity or a spring.

   • B: Being powered one way only is the single-acting arrangement.
   • C: A hydraulic piston must seal to separate its two chambers.
   • D: Double-acting cylinders are commonly used on aerials.

8. Before opening a hydraulic line or fitting for service, the safest practice is to:

   ARelieve trapped/stored pressure and mechanically support any raised load BOpen the fitting quickly while the system is fully pressurized CStand directly in front of the fitting as it is loosened DRev the engine to full PTO speed first
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   Answer: A. Relieve trapped/stored pressure and mechanically support any raised load

   Stored hydraulic pressure and raised loads are serious hazards; relieve the pressure and block or support the load before loosening any connection.

   • B: Opening a pressurized fitting risks a fluid-injection injury or sudden load movement.
   • C: Standing in front of a pressurized fitting risks a high-pressure injection injury.
   • D: Increasing PTO speed raises pressure and the hazard.

9. Besides simply storing fluid, an important function of the hydraulic reservoir is to:

   AAllow entrained air to separate and heat to dissipate BRaise the pressure of the fluid it supplies CFilter the engine's fuel before injection DKeep the batteries charged while the pump runs
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   Answer: A. Allow entrained air to separate and heat to dissipate

   The reservoir lets entrained air escape, lets heat dissipate, and lets contaminants settle out of the fluid.

   • B: A reservoir is unpressurized; the pump makes pressure against a load.
   • C: The reservoir holds hydraulic fluid, not fuel.
   • D: Charging is electrical; the reservoir has no electrical role.

10. The primary purpose of a system pressure-relief valve is to:

    ALimit maximum system pressure to protect components BIncrease the flow the pump delivers to the circuit CRemove entrained air from the hydraulic fluid DHold the aerial device in its raised position
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    Answer: A. Limit maximum system pressure to protect components

    A relief valve opens and diverts fluid to the tank when pressure exceeds its setting, protecting the system from overpressure damage.

    • B: A relief valve diverts flow on pressure; it adds no output.
    • C: Air separates in the reservoir; a relief valve answers to pressure.
    • D: Holding a load belongs to a holding or counterbalance valve.