Design accidental events and acceptance standards

For the purposes of the demonstration referred to in para (iii) of recommendation 4, the accidental events are to be identified by the operator. A design accidental event is an event which will not cause the loss of any of the following:- — the integrity of the TSR, — the passability of at least one escape route from each location on the platform, — the integrity of a minimum complement of embarkation points and lifeboats specified for personnel in the TSR, and — the passability of at least one escape route to each of these embarkation points, within the endurance period specified. Events more severe than this are referred to as residual accidental events (para 19.160). The acceptance standards for risk and endurance time should be set before the submission of the Safety Case. Standards should be set by reference to the ALARP principle. For the time being it should be the regulatory body which sets these standards. The operator should define the conditions which constitute loss of integrity of, and the standards of protection for, the TSR and escape routes to the TSR and from the TSR to the embarkation points; and should specify the minimum complement of embarkation points and lifeboats for the TSR (paras 19.158-159).