Optimal Proof-Testing Strategies for Safety-Related Systems Based on Continuous Time Markov Chain

Abstract

Maintenance activities for safety-related systems are generally required to ensure that the systems are working as intended. Regarding the maintenance activities, proof-testing is known as scheduled inspections and maintenance activities for detecting dangerous undetected faults which cannot be detected by diagnostic testing systems installed in the safety-related systems. However, the proof-testing needs a lot of cost and provokes decreasing of the availability for the whole system because the whole system is needed to shut down for proofing that the whole system is working as intended. We discuss analytical methodologies for obtaining optimal proof-testing interval with harmful risk and proof-testing cost by describing the behavior of the safety-related system based on a continuous-time Markov chain. Further, an analytical optimal policy for obtaining economic proof-testing interval is proposed in this paper.