Emerson Rosemount 8800D Series Safety Manual page 24

Proof tests
Figure 3-3:
C
0
B
A.
B.
C.
D.
E.
Figure 3-4:
C
0
B
A.
B.
C.
D.
20
Unit subjected to either no proof test or a comprehensive proof test
every 5 years
2 4 6
PFD (Probability of failure on demand)
Mission time (years)
PFD (average probability of failure on demand)
AVG
Predicted PFD
Predicted PFD + CPT (comprehensive proof test)
Unit subjected to a partial proof test every year and a comprehensive
proof test every 3 years
2 4 6
PFD (Probability of failure on demand)
Mission time (years)
PFD (average probability of failure on demand)
AVG
Predicted PFD + PPT (partial proof test) + CPT (comprehensive proof test)
8 10
8 10
Rosemount
™
8800D Safety Manual