Translation guide
Describes a system, plan, or device designed to revert to a safe condition in the event of failure, or a precautionary measure to prevent disaster.
The core engineering meaning: a mechanism that, if it fails, does so in a way that causes no harm (e.g., a brake that engages when power is lost).
An action or arrangement taken to ensure safety or prevent failure, often in non-engineering contexts like business or daily life.
フェイルセーフ is strictly an engineering term for automatic safe failure. 安全策 is a broader 'safety measure' that can be used in any context, including business or daily life. Use フェイルセーフ when describing a technical design; otherwise, 安全策 or 予防策 is more natural.
このブレーキはフェイルセーフです。
This brake is fail-safe.
プロジェクトには安全策が必要だ。
The project needs a fail-safe.
The direct loanword, widely used in technical and engineering contexts. It is the most common way to express the concept in Japanese.
このシステムはフェイルセーフ設計になっている。
This system has a fail-safe design.
A more literal Japanese compound meaning 'safe at time of failure'. Used in formal specifications and patents.
故障時安全機能を備えた装置。
A device equipped with a fail-safe function.
A descriptive phrase meaning 'to operate on the safe side'. Used in explanations rather than as a fixed term.
異常時には安全側に作動する設計です。
It is designed to operate on the safe side in case of abnormality.
Literally 'safety measure'. A natural, general term for any precaution taken to avoid risk.
念のため安全策を講じた。
We took a fail-safe measure just in case.
Means 'preventive measure'. Emphasizes stopping a problem before it happens, similar to a fail-safe in planning.
トラブルを避けるための予防策を用意した。
We prepared a fail-safe to avoid trouble.
Literally 'to take out insurance'. A figurative expression meaning to have a backup or safety net.
一応、保険をかけて別の案も考えておこう。
Let's think of another plan as a fail-safe, just in case.
The loanword 'backup'. Often used for fail-safe systems or alternative plans in IT and business.
システムにバックアップを組み込んでおく。
Build a fail-safe into the system.
A formal phrase meaning 'a measure taken just in case'. Suitable for official documents.
念のための措置として二重のチェックを行う。
As a fail-safe, we perform a double check.
Do not translate 'fail-safe' literally as 失敗安全 (しっぱいあんぜん) or 失敗しても安全 (しっぱいしてもあんぜん). These are not natural Japanese and will not be understood. Stick to the loanword フェイルセーフ or the contextual alternatives above.