Risk Assessment is gaining increasing acceptance as a tool in addressing the safety of offshore operations In addition to a complete assessment of an installation, which may form part of a Formal Safety Assessment, risk assessment techniques can be applied to specific safety related systems on a platform

This paper presents the results of a study of the risks associated with the hyperbaric rescue of divers It includes the identification of accident scenarios, and analysis of consequences of such events as ship collision, fire or explosion A particular feature of this assessment is the identification of effects which would impede evacuation, such as buckling of steel members, availability of strategic personnel, etc The study therefore included analysis of effects of incidents both on hardware, and also on personnel and procedures - Incorporation of event frequencies then enabled calculations to be made of the risk to the divers during an emergency situation In particular, comparison between the risks attached to different modes of evacuation enables decisions to be made, on safety grounds, with regard to the appropriate operational mode


This paper describes the application of risk assessment to a particular situation relating to diving operations On the floating production platform under consideration, plans to increase diving activity had been met with regulatory concerns over the ability to evacuate a large number of divers In a platform emergency The study which was undertaken enabled the system to be evaluated rationally in order to reach a decision on the feasibility of extending diving operations

Although the presentation is based upon a specific case study, it is intended to demonstrate the more general use of risk assessment In an offshore context This is discussed in the next section, followed by a description of the system which has been considered In the specific example included The risk assessment has been described in the following three sections and the paper is concluded with a discussion both of the specific applications to this problem, and also the more general application of risk assessment to Formal Safety Assessments


Onshore regulations relating to the safety of 'major hazard sites have now been In place for some years These, the so-called ‘CIMAH Regulations’1, require the subrnission, by the operator, of a Safety Case In order to demonstrate that the hazards have been identified and properly controlled, and hence that the risks have been minirnised Although quantification is not mandatory, it is clearly considered to be an important ingredient of any Safety Case2

The recent publication of the Cullen Report3 on the Inquiry Into the Piper Alpha disaster has demonstrated the need to bring offshore legislation into line with that onshore, with a requirement for Formal Safety Assessment Again, whilst the level of risk quantification is not prescribed, it is clearly implied that some attempt at a quantified risk assessment (QRA) is required Whilst operators are only beginning to realise the full implications of this requirement, it is already evident that QRA can provide a valuable tool in a range of applications relating to offshore safety

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