Failsafeläge

Failsafeläge, or fail-safe positions, refer to the default safe state that a system or component adopts when a fault occurs or power or control is lost. The concept is central to safety engineering: even in failure, the system should move to a state that minimizes risk to people and surroundings.

Typically a failsafeläge is achieved through passive mechanisms such as springs, gravity, or mechanical linkages that drive the device to the safe position without requiring external power. Some systems use energy storage, like springs, to guarantee a safe state when supply is interrupted. In contrast to fail-safe, terms such as fail-secure or fail-open describe alternate responses where the safe state may involve remaining locked or opening, depending on the design and hazard assessment.

Applications are widespread in safety-critical areas. Valves that shut off gas or steam when a fault occurs, braking systems that engage automatically, doors or gates that move to a safe position, and interlocks in industrial machinery are common examples. Railway signaling, elevator safety systems, and nuclear or aerospace safety mechanisms often incorporate failsafeläge to limit consequences of failures.

Design considerations include identifying potential failure modes, ensuring the safe state does not create new hazards, and confirming that the transition to the safe state happens reliably under fault conditions. Standards and methodologies such as failure modes and effects analysis (FMEA) or risk assessments guide the integration of failsafeläge into broader safety architectures.