EVT Hydraulic Systems & Aerial Apparatus Flashcards
6 cards from real EVT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 EVT Hydraulic Systems & Aerial Apparatus flashcards as text
What is the primary function of a hydraulic relief valve in an aerial apparatus system?
Answer: To prevent system overpressure by diverting excess fluid
A hydraulic relief valve protects the system by diverting excess fluid back to the reservoir when pressure exceeds a set limit.
Which type of hydraulic pump is most commonly used in aerial ladder apparatus due to its ability to deliver constant flow?
Answer: Piston pump
Piston pumps are preferred in aerial apparatus because they provide high-pressure, constant-flow output needed for reliable aerial operations.
According to NFPA 1901, aerial devices must be tested at what percentage above their rated working load?
Answer: 150%
NFPA 1901 requires aerial devices to be proof-tested at 150% of their rated working load during annual certification.
What condition is indicated when a hydraulic cylinder drifts under load with no control input?
Answer: Internal cylinder seal leakage
Cylinder drift under load indicates internal seal leakage, allowing fluid to bypass the piston and causing unintended movement.
What is the purpose of a hydraulic accumulator on an aerial apparatus?
Answer: Store pressurized fluid for emergency operations
A hydraulic accumulator stores pressurized fluid to provide emergency power for retracting the aerial if the primary pump fails.
What does a high hydraulic fluid temperature typically indicate during aerial apparatus operation?
Answer: Excessive load cycles or restricted flow
High hydraulic fluid temperature usually signals excessive load cycling, restricted flow, or a failing component causing heat buildup.