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What is the job of the safety valve fitted to the first air tank reached by the compressor?
- A.It supplies air to the trailer brakes first
- B.It vents air automatically if tank pressure rises above about 150 psi
- C.It holds the spring brakes off while parked
- D.It warns the driver with a buzzer at 60 psi
Correct answer
B. It vents air automatically if tank pressure rises above about 150 psi
Why
The safety valve is a last line of protection against over-pressurization if the governor fails to unload the compressor. It is normally set to open at about 150 psi and should never be adjusted by the driver.
Manual topic: Air Brakes - Safety Valve · From the General Knowledge practice bank (GK-103).