Facilitating \(\beta \) -Factor Estimation for Common Cause Failures of Safety-Related System

Common Cause Failures (CCF) have the potential to make safety-related systems fail. Hence, the safety-critical industries identify and quantify the probability of CCF using different methodologies. For example, industries like railways rely on a \(\beta \) -factor methodology suggested by the IEC 61508 standard, in which defense measures are established against CCF and \(\beta \) -factor (used in the estimation of the probability of CCF) quantified based on the application of those measures. However, this methodology had two main research problems (RP) they are, RP1: The standard’s inception was in 2010, and due to this the measures against the CCF that arose from the emerging new technologies were absent in the standard. Moreover, the methodology has not provided any means to permit new measures. RP2: The methodology is generalized and applicable to all safety-related systems using Electrical/Electronic/Programmable Electronic-based systems across different industries. However, the impact of CCF and the required defense measures against them would be distinct in each industry. Eventually, the negligence of these problems leads to conservative \(\beta \) estimations. Therefore this research aims to provide possible solutions for these two problems. For RP1, by proposing a methodology that enhances the IEC 61508 standard methodology in \(\beta \) -factor estimation and adopts a way that could consider new defense measures in addition to the existing measures. For RP2, we planned to demonstrate an approach to develop an industry-specific \(\beta \) -factor methodology focusing on railways. Later, the methodology is applied to a system i.e., Electro-dynamic braking of railway propulsion systems for \(\beta \) -factor estimation. This research would provide insights to industrial practitioners and researchers to develop industry-specific \(\beta \) -factor methodology to estimate more realistic \(\beta \) , by analyzing appropriate defense measures.