During a static leakage test, the maximum leakage rate for a double combination vehicle is:
Answers
3 psi in one minute.
6 psi in one minute.
8 psi in one minute.
The Correct Answer and Explanation is :
The correct answer is 3 psi in one minute.
A static leakage test is a method used to assess the air brake system’s ability to hold air pressure and check for any leaks in the system, especially for large vehicles like double combination vehicles (which consist of a tractor and multiple trailers). The test involves applying air pressure to the system and monitoring how much pressure is lost over a set period of time.
For double combination vehicles, the maximum leakage rate allowed during the static leakage test is 3 psi per minute. This means that if, during the test, the air system loses more than 3 psi of pressure in one minute, it indicates there may be a leak in the system. Any leakage above this limit typically signals that the vehicle’s air brake system is not functioning properly and requires inspection or repair.
This limit is based on the Federal Motor Carrier Safety Administration (FMCSA) regulations, which set standards for commercial vehicle safety. These standards ensure that the air brake system on combination vehicles is maintained to provide safe stopping power, especially under load. A higher leakage rate could potentially lead to brake failure or reduced braking efficiency, posing significant risks to road safety.
The leakage test is conducted in a stationary vehicle after the air system has been fully charged, and then the vehicle’s brakes are applied to ensure no significant pressure loss occurs. If the vehicle exceeds the 3 psi limit, maintenance or repairs must be made before the vehicle is considered roadworthy again.
For other vehicles, such as single vehicles, the permissible leakage rate may differ, but for a double combination vehicle, the standard remains 3 psi per minute. This test is part of regular safety checks to ensure vehicles meet safety standards and protect both the driver and other road users.