Modelling Weibull lifetime law and inspection based maintenance policy for safety instrumented systems
Résumé
Classical analytical models developed to quantify the availability of Safety Instrumented Systems (SIS) are currently based on the assumption of exponential lifetime distributions for all the units they are made of (Rausand 2014). The aim of the present work is to show how some stochastic modelling framework based on renewal processes can be used to generalise existing tools. The main goal is to include other lifetime laws than the exponential one (e.g. Weibull law) and to model the possible effects of inspection/maintenance policies. We focus on SIS that are used in low demand rate, whose mechanical parts are considered as passive units and which are supposed to act on demand. They are consequently periodically teste