Glossary
New Requirements of the IEC 61511

Aussi bon que neuf; as good as new (AGAN)

Calculation assumption used in the standard IEC 61508-6. After each periodic test, PFD(t) is assumed to return to its initial value.

Danger; hazard

Potential source of damage (EC 61511 :2016).

Risk; risk

Combination of the probability of damage and its severity (IEC 61511 :2016).

Safe failure fraction (SFF)

Proportion of a device's overall rate of random hardware failures that results in a safety failure or a detected unsafe failure (IEC 61511 :2003).

Accident scenario; scenario

Sequence of events leading from an initiating event to a (major) accident, whose sequence and...