defined conditioned for a specified time. So, it can be said that reliability is the extension of the term quality over
time and can be defined as “the time period over which a product meets the standards of quality for the period of
expected use” [1]. Moreover, it is a fundamental attribute for safety operations [2] as common methods are used for
their analysis and it happens that they require input from each other [3]. In reliability analysis the subject matter is
the uncertainty in the failure occurrences, noises and disturbances during product operation and consequences,
whereas the objective of safety is to protect the product against the uncertainties of its accidental scenarios [2]. Both
reliability and safety engineering aim at study, characterization, measurement, analysis of failure, its repair and
consequences to be able to improve operational system use. They result from product complexity, development of
technology, customer requirements, public awareness, market competition, safety and liability legal requirements,
former system failures and their consequences [4]