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.
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.
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.