The resilience goal may be specified in terms of the risks involved in the system operation. The risks may be expressed in terms of estimates of the Mean Time Between Incidences (MTBI).
The Target MTBI is a measure of acceptability of rate of incidences.
The Target MTBI may be obtained by analysis of the customer risks.
A customer risk analysis of a chemical plant dictates that any fault in the system operation might cause death and injury.
The regulator may require a minimal MTBI for plants in which a failure might involve injury or death.
The risk policy is the minimal MTBI required for particular risks. An example risk policy, applicable to safety-critical systems, is defined in the IEC 61508 safety standard
Updated on 20 Oct 2016.