Risk Assessment: Theory, Methods, and Applications

Appendix C

Glossary

Acceptable risk

Risks considered insignificant and not justifying further effort to reduce them (HSE, 2001a).

The risk that is understood and agreed to by the program/project, governing authority, mission directorate, and other customer(s) such that no further specific mitigating action is required (NASA, 2007).

Risk which is accepted in a given context based on the current values of society and in the enterprise (NS 5814, 2008).

The residual risk remaining after controls have been applied to associated hazards that have been identified, quantified to the maximum extent practicable, analyzed, communicated to the proper level of management, and accepted after proper evaluation [SSDVC-28 (DOE).

Accident

A sudden, unwanted, and unplanned event or event sequence that leads to harm to people, the environment, or other assets.

An unintended event or sequence of events that causes death, injury, or environmental or material damage (DEF-STAN 00–56, 2007).

An unwanted transfer of energy, because of lack of barriers and/or controls, producing injury to persons, property, or process, preceded by sequences of planning and operational errors, which failed to adjust to changes in physical or human factors and produced unsafe conditions and/or unsafe acts, arising out of the risk in an activity, and interrupting or degrading the activity (Johnson, 1980).

Alternative term: Mishap.

Accident scenario

A specific sequence of events from an initiating event to an undesired consequence ...