CDL Air Brakes TestAir Brake System PartsMedium
When inspecting an air brake system, a driver should check that the safety relief valve on the air tank opens and releases air when the pressure reaches what specific range?
- ABetween 250 psi and 275 psi.
- BBetween 100 psi and 125 psi.
- CBetween 200 psi and 225 psi.
- DBetween 150 psi and 175 psi.
Show answer & explanationAnswer & explanation
Correct answer: D. Between 150 psi and 175 psi.
The safety relief valve is designed to protect the air tanks and system from excessive pressure. It is typically set to open and release air if the pressure exceeds 150 psi, but no more than 175 psi.
Why the other options are wrong
- A. This pressure is dangerously high and would likely lead to system component failure or rupture.
- B. This range is typically where the air compressor governor cuts out, not where the safety valve activates.
- C. This pressure is excessively high and would indicate a severe malfunction of the safety valve or governor.
Air Tank Safety Valve
The safety relief valve on an air tank is a crucial safety device designed to prevent over-pressurization of the air brake system.
- It opens and releases air to prevent tank rupture.
- Activates if pressure exceeds 150 psi.
- Must open by 175 psi at the latest.
Memory trick: Safety valve: too much pressure, it shouts out loud!