UN/ISDR - UN Office for DRR [ 15 January 2009 ]
Definition:
The level of potential losses that a society or community considers acceptable given existing social, economic, political, cultural, technical and environmental conditions.
Comment: In engineering terms, acceptable risk is also used to assess and define the structural and non-structural measures that are needed in order to reduce possible harm to people, property, services and systems to a chosen tolerated level, according to codes or “accepted practice” which are based on known probabilities of hazards and other factors.