絶対安全な、安全装置のついた

WordNet

guaranteed not to fail; "a fail-safe recipe for cheese souffle"
a mechanism capable of returning to a safe state in case there is a failure or malfunction
eliminating danger by compensating automatically for a failure or malfunction; "a fail-safe device in a nuclear weapon to deactivate it automatically in the event of accident"
judge unacceptable; "The teacher failed six students"
get worse; "Her health is declining"
disappoint, prove undependable to; abandon, forsake; "His sense of smell failed him this time"; "His strength finally failed him"; "His children failed him in the crisis" (同)betray
fail to get a passing grade; "She studied hard but failed nevertheless"; "Did I fail the test?" (同)flunk, bomb, flush it
stop operating or functioning; "The engine finally went"; "The car died on the road"; "The bus we travelled in broke down on the way to town"; "The coffee maker broke"; "The engine failed on the way to town"; "her eyesight went after the accident" (同)go bad, give_way, die, give out, conk out, go, break, break_down
be unsuccessful; "Where do todays public schools fail?"; "The attempt to rescue the hostages failed miserably" (同)go wrong, miscarry
fail to do something; leave something undone; "She failed to notice that her child was no longer in his crib"; "The secretary failed to call the customer and the company lost the account" (同)neglect
prove insufficient; "The water supply for the town failed after a long drought" (同)run_out, give out
be unable; "I fail to understand your motives"
become bankrupt or insolvent; fail financially and close; "The toy company went bankrupt after the competition hired cheap Mexican labor"; "A number of banks failed that year"
fall short in what is expected; "She failed in her obligations as a good daughter-in-law"; "We must not fail his obligation to the victims of the Holocaust"
having reached a base without being put out; "the runner was called safe when the baseman dropped the ball"
a ventilated or refrigerated cupboard for securing provisions from pests
strongbox where valuables can be safely kept
(of an undertaking) secure from risk
free from danger or the risk of harm; "a safe trip"; "you will be safe here"; "a safe place"; "a safe bet"
below acceptable in performance; "received failing grades"
a flaw or weak point; "he was quick to point out his wifes failings" (同)weakness
failure to reach a minimum required performance; "his failing the course led to his disqualification"; "he got two flunks on his report" (同)flunk
the syllable naming the fourth (subdominant) note of the diatonic scale in solmization

PrepTutorEJDIC

『失敗』する,しくじる;落第する / 不足する,欠けている / 『衰える』,弱くなる / 〈会社などが〉破産する,倒産する / (いざというときに)〈人〉‘の'『役にたたない』,期待を裏切る,〈人〉‘を'見捨てる / 〈教師が〉〈学生・生徒〉‘を'落とす,‘に'落第点をつける / 〈学科・試験など〉‘に'『落第する』 / =failure
安全な,危険のない / 《come,arrive,bring,keepなどの補語にのみ用いて》無事な(に) / 危険を引き起こさない,危害を加えない / 安全を心がける,危険をおかさない / 『確かな』,まちがいのない / (野球で)セーフの / 『金庫』 / (食料などを入れる)安全戸棚,貯蔵容器
欠点,弱点;失敗,落第;破産 / …がないので,がない場合には
ファ(全音階の第4音)

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2013/04/03 10:26:54」(JST)

wiki en

[Wiki en表示]

For other uses, see Fail-safe (disambiguation).

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.

Significantly, despite popular belief to the contrary,^[1] a system's being "fail-safe" means not that failure is impossible/improbable, but rather that the system's design prevents or mitigates unsafe consequences of the system's failure; that is, if and when a "fail-safe" system "fails", it is "safe" or at least no less safe than when it is operating correctly.^[2]

Examples

Mechanical or physical

An aircraft lights its afterburners to maintain full power following an arrested landing aboard an aircraft carrier. If the arrested landing fails, the plane can safely take off again.

Aircraft landing on an aircraft carrier increases the throttle to full power at touchdown. If the arresting wires fail to capture the plane, it is able to take off again.^[3]
Coiling/rolling fire doors that are activated by building alarm systems or local smoke detectors must close automatically when signaled regardless of power. In case of power outage the coiling fire door does not need to close, but must be capable of automatic closing when given a signal from the building alarm systems or smoke detectors. A temperature sensitive fusible link may be employed to hold the fire doors open against gravity or a closing spring. In case of fire, the link melts and releases the doors, and they close.
Operation of some airport luggage carts requires that one hold down a given cart's handbrake switch at all times; if the handbrake switch is released, the brake will activate, and assuming that all other portions of the braking system are working properly, the cart will stop. The handbrake-holding requirement thus both operates according to the principles of "fail-safety" and contributes to (but does not necessarily ensure) the fail-security of the system.

See dead man's switch, a more extreme example that, depending on its placement in the system, can be used to render a system "safe" and/or "secure" against a failure that disables it.

Lawnmowers and snow blowers have a hand-closed lever that must be held down at all times. If it is released, it stops the blades or rotors rotation.
Air brakes on railway trains and air brakes on 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 to drive a train or truck with a serious leak in the air brake system.
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.
During early Apollo program missions to the Moon, the spacecraft was put on a free return trajectory — if the engines had failed at lunar orbit insertion, the craft would have safely coasted back to Earth.
Elevator cabins have a safety mechanism that wedges securely onto the guide rails to arrest a fall if the hoist cables were to fail.
Various devices that operate with fluids use fuses or valves as a fail-safe mechanism.
A railway semaphore signal is designed so that should the cable controlling the signal break, the arm returns to the "danger" position, preventing any trains passing the inoperative signal.
On diving watches, the rotating bezel used to measure dive time contains a ratchet so it can only be turned anti-clockwise. If the bezel is inadvertently rotated during the dive, it will only rotate so as to give a false reading of increased time spent below, prompting the underwater diver to return to the surface earlier than intended (with oxygen to spare) instead of later than intended (which could cause the diver to run out of oxygen and drown).

Electrical or electronic

Many devices are protected from short circuit with fuses. The destruction of the fuse will prevent destruction of the device.
Avionics using redundant systems to perform the same computation with voting logic to determine the "safe" result.
Traffic light controllers use a Conflict Monitor Unit to detect faults or conflicting signals and switch an intersection to all flashing red, rather than displaying potentially dangerous conflicting signals, e.g. showing green in all directions.^[4]
The automatic protection of programs and/or processing systems when a computer hardware or software failure is detected in a computer system. A classic example is a watchdog timer. 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.
The iron pellet ballast on the Bathyscaphe is dropped to allow the submarine to ascend. The ballast is held in place by electromagnets. If electrical power fails, the ballast is released, and the submarine then ascends to safety.
Inside a modern CPU are features to prevent damage through overheating. In the event of cooling failure, the CPU will throttle then shut down beyond a critical temperature threshold to avoid damage.
In industrial automation, alarm signals are usually "normally closed" (or active at 0). This insures that in case of a wire break the alarm will be triggered. If the signal were normally open, no wire failure would be detected.
In control systems, critically important signals can be carried by a complementary pair of wires (<signal> and <not_signal>). Only states where the two signals are opposite (one is high, the other low) are valid. If both are high or both are low the control system knows that something is wrong with the sensor or connecting wiring. Simple failure modes (dead sensor, cut/unplugged wires) are thereby detected. An example would be a control system reading both the NO and NC poles of a SPDT selector switch against common, and checking them for coherency before reacting to the input.

Procedural

As well as physical devices and systems fail-safe procedures can be created so that if a procedure is not carried out or carried out incorrectly no dangerous action results. For example:

In railway signalling signals which are not in active use for a train are required to be kept in the 'danger' position. The default position of every signal is therefore "danger", and therefore a positive action — setting signals to "clear" — is required before a train may pass. This practice also ensures that, in case of a fault in the signalling system, an incapacitated signalman, or the unexpected entry of a train, that a train will never be shown an erroneous "clear" signal.
Train drivers are instructed that a railway signal showing a confusing, contradictory or unfamiliar aspect (for example a colour light signal that has suffered an electrical failure and is showing no light at all) must be treated as showing "danger". In this way, the driver contributes to the fail-safety of the system.

Other terminology

Fail-safe (foolproof) devices are also known as poka-yoke devices. Poka-yoke, a Japanese term, was coined by Shigeo Shingo, a quality expert.^[5]^[6] "Safe to fail" refers to civil engineering designs such as the Room for the River project in Netherlands and the Thames Estuary 2100 Plan^[7]^[8] which incorporate flexible adaptation strategies or climate change adaption which provide for, and limit damage, should extreme events such as 500 year floods occur.^[9]

References

^ "Fail-safe". AudioEnglich.net. Accessed 2009.12.31
^ e.g., David B. Rutherford, Jr., "What Do You Mean — It's Fail-Safe?": Evaluating Fail-Safety in Processor-Based Vital Control Systems. 1990 Rapid Transit Conference
^ Harris, Tom. "How Aircraft Carriers Work". HowStuffWorks, Inc. Retrieved 2007-10-20.
^ Manual on Uniform Traffic Control Devices, Federal Highway Administration, 2003
^ Shingo, Shigeo; Andrew P. Dillon (1989). A study of the Toyota production system from an industrial engineering viewpoint. Portland, Oregon: Productivity Press. p. 22. ISBN 0-915299-17-8. OCLC 19740349
^ John R. Grout, Brian T. Downs. "A Brief Tutorial on Mistake-proofing, Poka-Yoke, and ZQC", MistakeProofing.com
^ "Thames Estuary 2100 Plan". UK Environment Agency. November 2012. Retrieved March 20, 2013.
^ "Thames Estuary 2100 (TE2100)". UK Environment Agency. Retrieved March 20, 2013.
^ Jennifer Weeks (March 20, 2013). "Adaptation expert Paul Kirshen proposes a new paradigm for civil engineers: 'safe to fail,' not 'fail safe'". The Daily Climate. Retrieved March 20, 2013.

UpToDate Contents

全文を閲覧するには購読必要です。 To read the full text you will need to subscribe.

1. 手術室における患者の安全性 patient safety in the operating room
2. 成人における偶発性低体温 accidental hypothermia in adults
3. 心臓自動能の増強 enhanced cardiac automaticity
4. 非浸潤性乳管癌：疫学、臨床症状、および診断 breast ductal carcinoma in situ epidemiology clinical manifestations and diagnosis
5. 妊娠中の重症筋無力症のマネージメント management of myasthenia gravis in pregnancy

English Journal

Non-attendance at diabetic eye screening and risk of sight-threatening diabetic retinopathy: a population-based cohort study.

Forster AS, Forbes A, Dodhia H, Connor C, Du Chemin A, Sivaprasad S, Mann S, Gulliford MC.SourceDepartment of Primary Care and Public Health Sciences, King's College London, Capital House, 42 Weston Street, London, SE1 3QD, UK, alice.s.forster@kcl.ac.uk.
Diabetologia.Diabetologia.2013 Oct;56(10):2187-93. doi: 10.1007/s00125-013-2975-0. Epub 2013 Jun 22.
AIMS/HYPOTHESIS: This study evaluated whether repeated non-attendance for diabetic eye screening is associated with the risk of sight-threatening diabetic retinopathy (STDR).METHODS: This was a cohort study of 6,556 residents with diabetes who were invited for screening between 2008 and 2011 in a po
PMID 23793717

Safe, stable, nurturing relationships as a moderator of intergenerational continuity of child maltreatment: a meta-analysis.

Schofield TJ, Lee RD, Merrick MT.SourceHuman Development and Family Studies, Iowa State University, Ames, Iowa. Electronic address: tommy@iastate.edu.
The Journal of adolescent health : official publication of the Society for Adolescent Medicine.J Adolesc Health.2013 Oct;53(4 Suppl):S32-8. doi: 10.1016/j.jadohealth.2013.05.004.
PURPOSE: The present paper summarizes findings of the special issue papers on the intergenerational continuity of child maltreatment and through meta-analysis explores the potential moderating effects of safe, stable, nurturing relationships (SSNRs).METHODS: Studies were selected for inclusion in th
PMID 24059937

Medication errors.

Cohen MR.SourcePresident of the Institute for Safe Medication Practices The reports described in Medication Errors were received through the ISMP Medication Errors Reporting Program. Report errors, close calls, or hazardous conditions to the Institute for Safe Medication Practices (ISMP) at http://www.ismp.org, 1-800-FAIL Safe, or ismpinfo@ismp.org. Michael R. Cohen is a member of the Nursing2013 editorial board.
Nursing.Nursing.2013 Oct;43(10):72. doi: 10.1097/01.NURSE.0000434326.33021.55.
PMID 24045829

Impact of minocycline on neurodegenerative diseases in rodents: a meta-analysis.

Li C, Yuan K, Schluesener H.AbstractAbstract Minocycline is a semisynthetic second-generation tetracycline derivative, and many publications provide evidence of its successful neuroprotection in a variety of animal models. We searched PubMed and Chinese CNKI databases from January 1992 to May 2012 for studies on minocycline in neurodegenerative diseases in rodents. A meta-analysis that adopted weighted Cohen's d effect sizes, percent overlap, Fail-Safe N statistics, and confidence intervals was conducted. In total, 16 English and 3 Chinese articles with high or medium quality were included in this meta-analysis. The treatment benefits for rodents from low-dose (5 mg/kg/day), moderate-dose (45, 50, or 55 mg/kg/day), and high-dose (90 mg/kg/day) minocycline were larger in Huntington's disease, Alzheimer's disease, and stroke mouse models, respectively. In rats, a moderate dose (45 mg/kg/day) of minocycline was most effective. In conclusion, minocycline exerts neuroprotective effects in rodent models of neurodegenerative diseases. Anti-inflammatory, antiapoptotic, and antioxidant activities are discussed as the basis of this effect. However, there is insufficient information from these animal models on side effects of minocycline therapy.
Reviews in the neurosciences.Rev Neurosci.2013 Oct 1;24(5):553-562. doi: 10.1515/revneuro-2013-0040.
Abstract Minocycline is a semisynthetic second-generation tetracycline derivative, and many publications provide evidence of its successful neuroprotection in a variety of animal models. We searched PubMed and Chinese CNKI databases from January 1992 to May 2012 for studies on minocycline in neurode
PMID 24077620