text: Reliability | Oil and Gas Drilling Glossary | IADCLexicon.org
  Ability of a component or system to perform its required function without failure during a specified time interval routine personnel transfer everyday routine personnel transfer, without specific supporting documentation (i.e. DNV GL approved personnel transfer procedure)
  The ability of a component or a system to perform its required function under given conditions for a given time interval.
  Indicator of the extent to which examination scores are consistent across different examination times and locations, different examination forms and different examiners
  [SOURCE: ISO/IEC 17024:2012, 3.18].
  〈measure〉 probability for an item to perform a required function under given conditions over a given
  z S m =
  Note 1 to entry: This is a time-dependent parameter.
  Note 2 to entry: This parameter is related on a continuous functioning from 0 to t.
  Note 3 to entry: For non-repairable items, Reliability and Availability are identical
  Note 4 to entry: In IEC 60500–191[14], the reliability is defined both as ability and as measure.
  Ability of a structure or a structural component to fulfill the specified requirements.
  The ability of a component or a system to perform its required function without failure during a specified time interval.
  Proportion of occasions a barrier or equipment item will function as designed (%).
  Note that the definition of availability given in IEC 60050-191:1990, 3.1.1, can be misleading because it can lead one to think that "availability" and "reliability" are the same concepts. This is not true because the meaning of "over a given time interval" is not at all the same for the concepts of "availability" and "reliability". Even if the definitions of "availability" and "reliability" seem very close, these concepts are completely different, specifically: availability: item working at a given instant (no matter what has happened before); reliability: item working continuously over a whole period of time. "Availability" characterizes a function that can be interrupted without any problem and "reliability," a function that cannot be interrupted over a whole period of time.