Description: Period of time from the commissioning of a plant, part of a plant, a component or a line system; Name: service life
Description: passed time period after comissioning of a system, sub-system, component or piping; Name: Operating time 
Description: ten times the logarithm to the base 10 of the ratio of the sound energy, j, to a reference value, j0, expressed in decibels; Name: sound energy level