How is Mean Time Between Failure (MTBF) defined?

Mean Time Between Failure (MTBF) is specifically defined as a measure of reliability for systems and components that can be repaired after a failure occurs. It represents the average time the system operates before it experiences a failure that requires maintenance or repair. The concept is crucial because it helps organizations assess the reliability and performance of their equipment and systems over time.

MTBF is typically calculated by taking the total operational time, or uptime, and dividing it by the number of failures that occur during that time. For repairable items, a higher MTBF signifies that the equipment has a longer operational time between failures, indicating greater reliability. This reliability metric is essential for planning maintenance schedules, managing spare parts inventory, and improving overall system performance.

In contrast, other definitions provided do not accurately capture the essence of MTBF. While metrics regarding system downtime, reliability for non-repairable items, or total maintenance costs are relevant in reliability engineering and maintenance management, they do not pertain specifically to the concept of MTBF, which is focused solely on the average time between failures of repairable systems.