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PFD and SIL
‣
PFD from the Dangerous Undetected Failure rate, Beta Factor, Proof Test Interval
and MTTR
SIL
PFDavg
Risk Reduction
4
0.0001 - 0.00001
10000 - 100000
3
0.001 - 0.0001
1000 - 10000
2
0.01 - 0.001
100 - 1000
1
0.1 - 0.01
10 - 100
9
Don’t forget the other SIL requirements - 1000 of them!