In dual air systems, how quickly should air pressure build?

For a dual air brake system, the correct expectation is that it should build air pressure from 85 psi to 100 psi within 45 seconds. This time frame is indicative of a well-functioning air brake system, ensuring that the truck can achieve sufficient air pressure for safe braking operations.

Maintaining appropriate air pressure is critical for ensuring the reliability and effectiveness of the brakes. In practice, when air pressure builds adequately within this time frame, it demonstrates that the system is efficiently compressing air without significant leaks or other mechanical issues.

Building air pressure from 85 to 100 psi in this specific period ensures that the brakes can engage properly when needed. In contrast, other pressure ranges and timeframes provided do not align with the standards expected for a dual air system. Hence, the correct answer establishes a benchmark for operational performance in heavy-duty vehicles.