Time effects in criteria for acceptable risk

The paper proposes new answers to some questions that occur frequently in practice, such as: “Should you discount future life risks and, if so, how?”, or “How can the acceptance criteria be applied when the risks and costs are not simultaneous, or are time series rather than numbers?” The solutions apply to many safety regulations or projects, when only the environmental, social and cultural consequences are secondary for acceptance in comparison with the costs and the risk to life or health. It is shown how discounting need be applied to financial quantities only, entirely obviating the ethical difficulties that go with the concept of “the value of a human life”.