| tec. |
fail-safe (A fail-safe or fail-secure device is one that, in the event of failure, responds in a way that will cause no harm, or at least a minimum of harm, to other devices or danger to personnel. "Fail-safe[ty]" should not be confused with "fail-secur[ity]." A fail-secure component of a system secures that system (or at least the portion to which the component is dedicated) in the event of a failure either of that component or elsewhere in the system. For example, during a failure of an ingress-egress control system, e.g., a user propping a door open somewhere in a building, a fail-secure lock will close, lock, and remain locked even when a user attempts to unlock it with the key that the user usually employs. In such a case, an independent release, such as a reboot or disarming of the securing mechanism, is required. In contrast, a component may be considered fail-safe even if its failure does not secure the system. For example, if a door locked from the inside is left unlocked or is unlocked at the wrong time, it has failed (in some cases, along with the entire system), the door may be (but is not necessarily) fail-safe if its being unlocked does not open it or attract additional attention to its unlocked state. WAD Alexander Demidov) |
