Note 1 to entry: The interval duration can be expressed in units appropriate to the item concerned, e.g. calendar time, operating cycles, distance run, etc., and the units should always be clearly stated.

Note 2 to entry: Given conditions include aspects that affect reliability, such as: mode of operation, stress levels, environmental conditions, and maintenance.

Note 3 to entry: Reliability can be quantified using measures defined in Section 192-05, Reliability related concepts: measures. One of these measures is “reliability ” defined in 192-05-05. The two meanings of the term reliability (according to the definitions 192-01-24 or 192-05-05) shall be distinguished according to its context of use.