Three things must be checked when verifying that a given Safety Instrumented Function (SIF) design meets a Safety Integrity Level (SIL). These are:
· Systematic Capability or Prior Use Justification for each device meets the SIL level of the SIF
· Architecture Constraints (minimum redundancy requirements) are met
· A PFDavg calculation result is within the range of numbers given for the SIL level
A PFDavg calculation is the most common and perhaps the most important of the three performance metrics. A proper PFDavg calculation should be done based on a number of variables.
This web seminar will describe how all of these variables impact the PFDavg calculation and show the importance of each variable. The overall impact will be shown to be up to two SIL levels!