14
57-656 SIL Safety Manual for ECLIPSE Model 706
8.3
Specific Model 706 Values
8.4
PFD Graph
The resulting PFD
AVG
Graph generated from the exSILentia
tool for a proof test interval of one year is displayed below.
It is the responsibility of the Safety Instrumented Function
designer to perform calculations for the entire SIF.
exida
recommends the accurate Markov-based exSILentia tool for
this purpose.
For SIL 2 applications, the PFD
AVG
value needs to be
≥
10
-3
and < 10
-2
. This means that for a SIL 2 application, the
PFD
AVG
for a 1-year Proof Test Interval of the Model
706-511x-xxx is approximately equal to 6.7% of the range.
These results must be considered in combination with
PFD
AVG
values of other devices of a Safety Instrumented
Function (SIF) in order to determine suitability for a specific
Safety Integrity Level (SIL).
Product
ECLIPSE
Model 706-51Ax-xxx
SIL
SIL 2
HFT
0
SFF
93.0%
PFDavg
6.67E-04
Proof Test Interval
Annually
(refer to PFD Graph below)
Specific Model 706
PFD
AVG
value for a single, Model 706-511x-xxx
with proof test intervals of one year.
