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

RISK-BASED INSPECTION METHODOLOGY, PART 3—CONSEQUENCE OF FAILURE METHODOLOGY 3-21
The equation for probability weighting of the component damage consequence areas is given by
Equation (3.27).
CA
flam
f , cmd
⎛
4
flam
⎜∑
gffn
⋅CAcmd , n ⎟
n=
1
= ⎜
⎟
⎜ gfftotal
⎟
⎜
⎝
⎞
⎟
⎠
(3.27)
The equation for probability weighting of the personnel injury consequence areas is given by Equation (3.28).
CA
flam
f , inj
⎛
4
flam
⎜∑
gffn
⋅CAinj,
n ⎟
n=
1
= ⎜
⎟
⎜ gfftotal
⎟
⎜
⎝
⎞
⎟
⎠
(3.28)
In Equation (3.27) and Equation (3.28), the
Table 3.1.
4.8.8 Calculation of Consequence Area
gffn
for each release hole size and
gfftotal
are provided in Part 2,
a) STEP 8.1—Select the consequence area mitigation reduction factor, fact
mit , from Table 4.10.
b) STEP 8.2—For each release hole size, calculate the energy efficiency correction factor, eneff
n , using
Equation (3.18).
c) STEP 8.3—Determine the fluid type, either TYPE 0 or TYPE 1, from Table 4.1.
d) STEP 8.4—For each release hole size, calculate the component damage consequence areas for
AINL−CONT
Autoignition Not Likely, Continuous Release (AINL-CONT), CA cmd , n
.
1) Determine the appropriate constants a and b from the Table 4.8. The release phase as determined in
STEP 1.4 will be needed to assure selection of the correct constants.
a a cmd
AINL−CONT
= (3.29)
b b cmd
AINL−CONT
= (3.30)
2) Use Equation (3.31) to calculate the consequence area.
b
( ) ( )
CA = a rate ⋅ − fact
(3.31)
AINL−CONT
cmd , n n
1
mit
e) STEP 8.5—For each release hole size, calculate the component damage consequence areas for
AIL CONT
Autoignition Likely, Continuous Release (AIL-CONT), CA − cmd , n
.
1) Determine the appropriate constants, a and b, from the Table 4.8. The release phase as determined
in STEP 1.4 will be needed to assure selection of the correct constants.
a = a −
(3.32)
AIL CONT
cmd