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: PN (nominal pressure) is an alphanumeric variable for reference purposes, relating to a combination of mechanical and measurement properties of a pipe component. It comprises the letters PN followed by a dimensionless number (according to EN 1333/96.08); Name: Nominal pressure of the muffs, A2