With the maturity of the offshore industry, health and safety is receiving increasing attention from all parties concerned. One of the areas which has been identified as key element in ensuring safety in complex process plants, such as offshore production platform, is the permit to work system. Its importance has been shown by the tragic events of Piper Alpha. This paper examines the role of the permit to work system (PTW) in offshore safety. The current practices of managing the PTW are discussed and the shortcomings of manual and database approaches are identified. It then proceeds to show how a knowledge based system approach can be applied to this problem to overcome some of the difficulties of the present methods. Functional requirements of such a system are discussed. The computer hardware and software limitations are taken into account to produce a practicable solution. The paper analyses the types of information required and the reasoning process to produce a PTW. Based on this, a possible framework of the expert system is suggested and methods of eliciting the knowledge are explored. Finally, expected benefits and problems of using such an expert system in an advisory capacity are discussed. 1.


The basic principles of Industrial Safety were set out in the mid 1920's by an American safety engineer called H.W. Heinrich [5]. They were the acknowledged inspiration for an approach to safety which in 1974 was embodied in the United Kingdom as the Health and Safety of Work Act. Heinrich concluded that "Acts of God" did sometimes occur, but in his experience, accidents were normally caused on earth, not in heaven. People were responsible at all levels, from managers for sloppy organisation, to the workforce for lack of awareness.

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