The indicator evaluates the availability of the item during the required time. The Achieved uptime is the period when the physical assets are able to perform the required function.
According to the definition of the EN15341 standard, the M10 indicator is the time-based availability indicator, whose numerator includes as input data the operating time (OT) completed during the required time, the Standby time and the Down time due to external reasons excluding the Idle time. (The item is not expected to perform while it is in an Idle state). The DT during the required time occurs due failures and restoration actions.
OT: Operating time, DT: Down time; RT: Required time
During a certain required time period the increasing of the number of occurred failures may lead to decrease of this KPI value. The increasing of the duration of the repair activities may also have negative influence on the KPI value.
It is recommendable that in case of a significant decrease of the time-based availability M10 to analyse whether the decrease is attributable to the number of failures or to the increase of the time to restoration (TTR). Should the latter occur an accurate analysis of the TTR time components is recommended to discover that the active repair time or technical, logistic, or administrative delay time components caused the negative influence.