Safety system design optimisation using a multi-objective genetic algorithm

This paper describes a design optimisation process applied to systems that require a high likelihood of functioning on demand. It is imperative that the best use of the available resources is made and an optimal rather than just an adequate system design is produced. The contribution of this research is in the development of an integrated approach which not only considers the primary system objective, availability of the system, but caters for all critical factors imperative to obtain an optimal system design. This research therefore combines the latest advantages of the fault tree analysis technique and the binary decision diagram method along with a multi-objective optimisation approach. The application area is a High Integrity Protection System of an offshore platform. The optimisation criteria involves unavailability, cost, spurious trip frequency and maintenance down time. The results produced using this method are compared to those obtained by exhaustive search.