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

RISK-BASED INSPECTION METHODOLOGY, PART 3—CONSEQUENCE OF FAILURE METHODOLOGY 3-51
Phase of Fluid at Normal
Operating (Storage) Conditions
Table 4.3—Level 1 Guidelines for Determining the Phase of a Fluid
Phase of Fluid at Ambient
(After Release) Conditions
Determination of Final Phase for
Consequence Calculation
Gas Gas Model as gas
Gas Liquid Model as gas
Liquid
Gas
Model as gas unless the fluid boiling point at
ambient conditions is greater than 80 °F, then
model as a liquid
Liquid Liquid Model as liquid
Table 4.4—Release Hole Sizes and Areas Used in Level 1 and 2 Consequence Analyses
Release Hole
Number
Release Hole Size
Range of Hole
Diameters
(in.)
Release Hole Diameter,
1 Small 0 to 1 /4 d
1
= 0.25
2 Medium > 1 /4 to 2
3 Large >2 to 6
(in.)
d
2
= 1
[ D ]
d2 = min , 1
d
3
= 4
[ D ]
d3 = min , 4
4 Rupture >6 d = [ D ]
4
min , 16
d
n
Table 4.4M—Release Hole Sizes and Areas Used in Level 1 and 2 Consequence Analyses
Release Hole
Number
Release Hole Size
Range of Hole
Diameters
(mm)
Release Hole Diameter,
(mm)
1 Small 0 to 6.4 d
1
= 6.4
2 Medium >6.4 to 51
3 Large >51 to 152
d
2
= 25
[ D ]
d2 = min , 25
d
3
= 102
[ D ]
d3 = min , 102
4 Rupture >152 d = [ D ]
4
min , 406
d
n