Emerson Rosemount 8800D Series - Page 25

Unit subjected to a partial proof-test every year and a comprehensive
proof test every 5 years
Figure 3-5:
A
B
D
D
C
0 2 4 6 8 10
A. PFD (Probability of failure on demand)
B. Mission time (years)
C. PFD
AVG
(average probability of failure on demand)
D. Predicted PFD + PPT (partial proof test) + CPT (comprehensive proof test)
Proof tests
Safety Manual 21