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

3-32 API RECOMMENDED PRACTICE 581
leak
The term CA
inj,
n
in Equation (3.76) represents the personnel injury areas for each of the holes sizes either due
to steam or acid releases as described in Section 4.10.2 and Section 4.10.3.
4.10.6 Calculation of Nonflammable, Nontoxic Consequence Areas
a) STEP 10.1—For each release hole size, calculate the nonflammable, nontoxic consequence area.
CONT
INST
1) For Steam—Calculate CA
inj,
n
using Equation (3.69) and CAinj,
n
using Equation (3.70).
CONT
2) For Acids or Caustics—Calculate CA
inj,
n
for liquid releases using Equations (3.72), (3.74), and (3.75).
INST
Note that data are not provided for an instantaneous release; therefore, CA
,
= 0.0 .
b) STEP 10.2—For each release hole size, calculate the instantaneous/continuous blending factor,
IC
fact .
n
For steam, use Equation (3.71). For Acids or Caustics,
IC
fact = 0.0 .
c) STEP 10.3—For each release hole size, calculate the blended nonflammable, nontoxic personnel injury
leak
consequence area for steam or acid leaks, CA
inj,
n
, using Equation (3.86) based on the consequence areas
from STEP 10.1 and the blending factor,
fact
IC
n
n
inj n
, from STEP 10.2. Note that there is no need to calculate
a component damage area for the Level 1 nonflammable releases (steam or acid/caustic):
leak
CA
,
= 0.0
(3.77)
cmd n
nfnt
d) STEP 10.4—Determine the final nonflammable, nontoxic consequence areas for personnel injury, CA
inj
,
using Equation (3.78) based on consequence areas calculated for each release hole size in STEP 10.3.
Note that there is no need to calculate a final nonflammable, nontoxic consequence area for component
damage area for the Level 1 nonflammable releases (steam or acid/caustic), or:
nfnt
CA
,
= 0.0
(3.78)
f cmd
4.11 Determine the Component Damage and Personnel Injury Consequence Areas
4.11.1 Overview
The final consequence areas for component damage and personnel injury are the maximum areas of those
calculated for:
a) flammable consequence; see Section 4.8;
b) toxic consequence; see Section 4.9;
c) nonflammable, nontoxic consequence; see Section 4.10.
4.11.2 Final Component Damage Consequence Area
The final component damage consequence area is:
flam tox nfnt
CAf , cmd
= max ⎡
⎣CAf , cmd
, CAf , cmd
, CA ⎤
f , cmd ⎦
(3.79)