What voting configurations are required for each SIL level?
Obtaining a desired SIL level is dependent on a multitude of factors. The type of technology employed, the number of system components, the probability of failure on demand (PFD) numbers for each component, the system architecture (e.g., redundancy, voting), and the proof testing intervals all play a significant role in the determination of a SIL level. There is not a standard answer for what voting configurations are required for each SIL level. The voting architecture must be analyzed in the context of all the factors noted above.
