Description: time-related proportion within a given period during which an object was able to perform when required; Name: Time-related availability
Description: During a given period of time, percentage of the time during which an item was able to perform when required ; Name: Time based availability
Description: ten times the logarithm to the base 10 of the ratio of the sound power of a source, p, to a reference value, p0, expressed in decibels; Name: sound output level