Economic Proof-Testing Intervals for E/E/Pe Safety-Related System with Harmful Risk

Abstract

E/E/PE safety-related systems play an important role in ensuring the functional safety especially for the safety-critical systems. In fact, the E/E/PE safety-related systems are widely implemented in several types of systems, such as automotive and chemical plant control systems, for the safe operation of them. In the operation of the systems, proof-testing, which is known as scheduled periodic inspections or maintenance activities, is conducted for maintaining certain level of safety integrity required to the E/E/PE safety-related system. However, the proof-testing needs a lot of time and cost for checking and proofing whether the safety-related system satisfies the safety requirement in operation. We discuss economic strategies for supporting design of proof-testing interval by focusing on the trade-off relationship between the maintenance cost and the risk at harmful event occurrence.