Which method uses a defined airflow limit to gauge leakage, and what is that limit?

Which method uses a defined airflow limit to gauge leakage, and what is that limit?

• A. Brake Pipe Leakage Method; 60 CFM
• B. Air Flow Method (AFM); 30 CFM
• C. Air Flow Method (AFM); 60 CFM
• D. Automatic Brake Pipe Leakage Method; 60 CFM

Answer: (C)

The key idea is using a fixed airflow to measure leakage directly. The Air Flow Method (AFM) applies a steady flow and gauges how much air leaks past the system, with a defined threshold to pass or fail. The specified limit is 60 cubic feet per minute (CFM); if leakage stays at or below 60 CFM, the system passes, otherwise it indicates an excessive leak that needs repair. This method is chosen because it provides a clear, quantitative criterion for leakage, unlike pressure-decay methods.

The key idea is using a fixed airflow to measure leakage directly. The Air Flow Method (AFM) applies a steady flow and gauges how much air leaks past the system, with a defined threshold to pass or fail. The specified limit is 60 cubic feet per minute (CFM); if leakage stays at or below 60 CFM, the system passes, otherwise it indicates an excessive leak that needs repair. This method is chosen because it provides a clear, quantitative criterion for leakage, unlike pressure-decay methods.