Reliability performance of safety instrumented systems: A common approach for both low- and high-demand mode of operation

A novel method for SIL verification based on system degradation using reliability block diagram

“…Innal [17] studied PFD G calculations and got the same formulae as IEC 61508 by using a continuous Markov model to approximate the exact Markov model, besides, he also explored other approaches to calculate PFD G . Jin [18] gave a common approach covering both low-and high-demand modes of operation and got results that are close to IEC 61508-6 by using Markov model. Dutuit [19] presented a methodology to assess the PFD G by means of Fault Trees and got similar results compared to the results obtained by means of Monte Carlo Simulations based on a Petri net model.…”

New PFH-formulas for k-out-of-n:F-systems

“…The fraction of DU-failures that are revealed by proof-tests is called the proof-test coverage (PTC) [12]. The PTC is also called functional test coverage in some references, e.g., [15]. The fraction of DU-failures that are not revealed by proof-tests is then (1À PTC).…”

“…Some researchers prefer not to distinguish the SIS operational modes and use a common reliability measure with basis in Markov modeling [3,[13][14][15]17,19,23]. Despite the limitations in modeling capacity, the simplified formulas are still preferred by most practitioners, due to their simplicity.…”

SIL verification for SRS with diverse redundancy based on system degradation using reliability block diagram

“…In most literatures about SIL verification, redundant channels in a voting group are assumed to be statistically independent and identical [10][11][12][13]. However, in many practical applications, not all channels in a voting group can be treated as identical because they have different failure rates and diagnostic coverages, i.e.…”