API RP 581 - 3rd Ed.2016 - Add.2-2020 - Risk-Based Inspection Methodology

RISK-BASED INSPECTION METHODOLOGY, PART 3—CONSEQUENCE OF FAILURE METHODOLOGY 3-53
Table 4.7—Leak Durations Based on Detection and Isolation Systems
Detection System Rating Isolation System Rating Maximum Leak Duration, ld
max
A
A
A
B
B
C
A
B
C
A or B
C
A, B, or C
20 minutes for 1 /4 in. leaks
10 minutes for d2 min [ D, 1]
5 minutes for d [ D ]
= leaks
3
= min , 41 leaks
30 minutes for 1 /4 in. leaks
20 minutes for d2 min [ D, 1]
10 minutes for d [ D ]
= leaks
3
= min , 41 leaks
40 minutes for 1 /4 in. leaks
30 minutes for d2 min [ D, 1]
20 minutes for d [ D ]
= leaks
3
= min , 41 leaks
40 minutes for 1 /4 in. leaks
30 minutes for d2 min [ D, 1]
20 minutes for d [ D ]
= leaks
3
= min , 41 leaks
1 hour for 1 /4 in. leaks
30 minutes for d2 min [ D, 1]
20 minutes for d [ D ]
= leaks
3
= min , 41 leaks
1 hour for 1 /4 in. leaks
40 minutes for d2 min [ D, 1]
20 minutes for d [ D ]
= leaks
3
= min , 41 leaks