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: amount of the absolute value of the total head above the head, equivalent to the vapour pressure of the liquid at the particular temperature, with reference to the NPSH datum plane; Name: net positive suction head