7.4.4 Risk Tolerability A quantified risk assessment should be used to produce a risk estimate to judge against the risk tolerability criteria. This assessment should be to a level of detail sufficient to show that the proposed option does not impose risks that are intolerable. Guidance on how to undertake such a risk assessment at the early stage of a design is given below. For the first well of a number of wells, the safety case should also demonstrate that the risk from the final arrangement of all wells is below the Upper Tolerability Level.
