Safe Failure

Definition(s)


Safe Failure

failure of a safety system which tends to favour a given safety action

Note 1 to entry: The concept of safe failure is illustrated in Figure B.1.

Note 2 to entry: A failure is safe only with regard to a given safety function. This is a systemic failure in

relationship with a given safety action performed by the safety system. This concept is irrelevant for an

individual item on the shelves.

Note 3 to entry: The non-critical safe failures basically increase the probability of success of the safety function.

The critical safe failures initiate the related safety actions when this is not needed (see spurious failures).

 

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Source: ISO/TR 12489:2013(E) Reliability modelling and calculation of safety systems. Global Standards