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Calculation of optimum proof test intervals for maximum availability
Author(s) -
Duke Geoff R.
Publication year - 1986
Publication title -
quality and reliability engineering international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.913
H-Index - 62
eISSN - 1099-1638
pISSN - 0748-8017
DOI - 10.1002/qre.4680020304
Subject(s) - unavailability , reliability engineering , reliability (semiconductor) , duration (music) , computer science , failure mode and effects analysis , interval (graph theory) , hazard , test (biology) , task (project management) , engineering , mathematics , art , power (physics) , chemistry , physics , literature , organic chemistry , quantum mechanics , combinatorics , paleontology , systems engineering , biology
Failure mode and effect analysis (FMEA) is often performed when assessing equipment reliability. Some failure modes can occur that are only revealed when a demand is placed upon the system, thus causing a hazard. Such failures are only detectable by regular proof testing of the system. Availability calculations generally do not take into consideration down‐time caused by the duration of such proof tests. Testing of a large system is both laborious and time consuming, and may cause either partial or total system unavailability. Microprocessor based equipment reduces the duration of this task, but the question arises of how often?' The following method shows how the optimum proof test interval can be determined based on Markovian reliability models. It should be borne in mind that figures used in reliability prediction should not be considered to be precise data. Such figures should be treated as approximations for comparative use only. The purpose of this paper is to provide a guide for use by engineers involved in reliability/availability prediction; it serves to replace intuitive decisions.