Description: Period of time during which an item performs its intended function, it includes all the time a machine is continuously running from start-up until it is shut down.; Name: ot
Description: passed time period after comissioning of a system, sub-system, component or piping; Name: Operating time 
Description: The norm in fixed relation to the feature being described. This defines the parameters that influence the contents of the correlated feature. Type and number of the norm with issue year and issue month must be given, e.g. DIN ISO 4711:YYYY-MM.; Name: Reference norm of the static seal, housing