MTBF is a metric for failures in repairable systems. For failures that require system replacement, typically people use the term MTTF (mean time to failure). For example, think of a car engine. When calculating the time between unscheduled engine maintenance, you'd use MTBF—mean time between failures.

What is MTBF used for?

Mean time between failures (MTBF) is the average time between system breakdowns. MTBF is a crucial maintenance metric to measure performance, safety, and equipment design, especially for critical or complex assets, like generators or airplanes. It is also used to determine the reliability of an asset.

What does an MTBF of 1000 hours telling us?

MTBF = Number of operation hours ÷ Number of failures

The pumps operated for 100 hours each over the course of a year, totalling 1,000. The pumps failed 16 times in total over that year. This means that the mean time between failures for these pumps is 62.5 hours.