What is the acceptable PSI loss during an air leak check within one minute?

The acceptable PSI loss during an air leak check is considered to be no more than 3 PSI within one minute. This standard is important because it indicates that the air brake system is functioning properly and is not compromised by leaks, which could lead to potential safety hazards when the vehicle is in operation.

When performing a pre-trip inspection, checking for air leaks is crucial to ensure that the air brake system maintains adequate pressure and responds effectively when applied. A loss greater than 3 PSI could signify an issue that requires further inspection and maintenance to prevent failures while driving.

Lower thresholds, such as 1 or 2 PSI, would be seen as overly stringent for practical operational parameters, as even minor environmental factors or minor system tolerances could lead to fluctuations that exceed these lower limits. Conversely, allowing a loss of up to 5 PSI might not provide a sufficient safety margin, as it may indicate more serious leakage that could compromise brake performance. Therefore, 3 PSI serves as a balanced standard that provides a reasonable allowance for acceptable air loss while still ensuring safe operation of the vehicle's braking system.