How are MTTR and MTBF calculated?
MTTR / Mean Time To Repair = average duration of repair (time from malfunction to production of the first OK parts)
MTBF / Mean Time Between Failure = average duration between two incidents
ema Plant Designer uses an exponential function to model the distribution function for both the MTTR and the MTBF. The assumption that an exponential function generally represents the respective relationship well has been confirmed in many studies, so this is also our basis.
The exponential function can then be described as: Expected value = MTTR or MTBF = 1 / λ. Depending on the size of the MTTR or MTBF, the exponential function will be flatter or steeper
This means that many short downtimes and few long downtimes are represented in relation to the MTTR and many short intervals between two failures and few long intervals between two failures are represented in relation to the MTBF.