Question Air pressure should build up in a single air system within: Answers 15 minutes. 12 minutes. Three minutes. Explanation In single air systems, air pressure should build from approximately 50 to 90 psi within three minutes. Take a FREE Practice Test Now This questions appears in the following tests: Alabama Knowledge Test Class A , Hawaii Air Brakes , Maine Air Brakes , Michigan Air Brakes , Missouri Air Brakes , New Mexico Air Brakes , South Dakota Air Brakes , Washington Air Brakes , Wisconsin Air Brakes , Wyoming Air Brakes ,