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(Redirected from Fail safe)

The term 'fail-safe' or 'fail-secure' is used to describe:

★ A device which, if (or when) it fails, fails in a way that will cause no harm or at least a minimum of harm to other devices or danger to personnel. Examples include:

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★ Luggage carts in airports in which the hand-brake must be held down at all times. If it is released, the cart will stop. See dead man's switch.

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★ Air brakes on railway trains and trucks. The brakes are held in the 'off' position by air pressure created in the brake system. Should a brake line split, or a carriage become de-coupled, the air pressure will be lost and the brakes applied. It is impossible for the train to be driven with a leak in the brake system.

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★ Avionics using redundant systems to perform the same computation with voting logic to determine the "safe" result.

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★ Motorized gates - In case of power outage the gate can be pushed open by hand with no crank or key required. However, as this would allow virtually anyone to go through the gate, a ''fail-secure'' design is used: In a power outage, the gate can only be opened by a hand crank that is usually kept in a safe area.

★ An operation which ensures that a failure of equipment, process, or system does not propagate beyond the immediate environs of the failing entity.

★ The automatic protection of programs and/or processing systems when a hardware or software failure is detected in a computer system. See fail-safe (computer).

★ A control operation or function that prevents improper system functioning or catastrophic degradation in the event of circuit malfunction or operator error, for example, the 'failsafe' track circuit used to control railway block signals.

★ A system which has been structured such that it cannot fail (or that the probability of such failure is extremely low) to accomplish its assigned mission regardless of environmental factors. Examples include:

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★ The hardening of a nuclear missile bunker or the dispersion of nuclear bombers to multiple secret locations

★ A precautionary secondary mechanism that achieves the same task as the primary mechanism.

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★ The activation of grenades when the primary detonator is destroyed.

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★ A device that activates explosives that releases lethal gas when destroyed.

★ ''Fail-Safe'' (novel), a 1962 novel by Eugene Burdick and Harvey Wheeler about an accidental sortie of American nuclear bombers against the USSR.

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★ ''Fail-Safe'' (1964 film), a 1964 film directed by Sidney Lumet.

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★ ''Fail-Safe'' (television), a 2000 made-for-television play based on the novel starring George Clooney.

★ Fail Safe is an episode of the science fiction television series Stargate SG-1.

★ Failsafe (UK band), a Preston based Indie-Rock band.
Fail-safe (foolproof) devices are also known as Poka-Yoke devices. Poka-yoke, a Japanese term, was coined by Shigeo Shingo, a quality guru.
FailSafe - a Company in South Africa who develop Software

Contents

See also

See also

★ Air safety

★ Damage tolerant design

★ Fail-deadly

★ Poka-yoke

★ Reliability

★ Safe-life design

★ Safety engineering

★ Software Developers