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

3-112 API RECOMMENDED PRACTICE 581
a) flammable consequences (see Section 5.8);
b) toxic consequences (see Section 5.9);
c) nonflammable, nontoxic consequences (see Section 5.10).
5.11.2 Final Component Damage Consequence Area
The final component damage consequence area is calculated using Equation (3.202). Since the consequence
areas associated with nonflammable, nontoxic releases and safe events are all associated with the same
probability (the probability of non-ignition, given a release), the maximum area is taken to maintain a total
probability of events equal to 1.0. Although the consequence area of a safe release is zero, it is included in the
calculation for completeness.
flam safe nfnt
CAf , cmd
= CAf , cmd
+ max ⎡
⎣psafe⋅CAf , cmd
, CA ⎤
f , cmd ⎦ (3.202)
5.11.3 Final Personnel Injury Consequence Area
The final personnel injury consequence area is calculated using Equation (3.203). Since the consequence
areas associated with nonflammable, nontoxic releases, toxic releases, and safe events are all associated with
the same probability (the probability of non-ignition, given a release), the maximum area is taken to maintain
a total probability of events equal to 1.0. Although the consequence area of a safe release is zero, it is included
in the calculation for completeness.
flam safe tox nfnt
CAf , inj
= CAf , inj
+ max ⎡
⎣psafe⋅CAf , inj
, CAf , inj,
CA ⎤
f , inj ⎦ (3.203)
5.11.4 Final Consequence Area
The final consequence area is:
CA = max ⎡
⎣CA , CA ⎤
⎦ (3.204)
f f , cmd f , inj
5.11.5 Calculation for Final Consequence Area
a) STEP 11.1—Calculate the final component damage consequence area, CA
f , cmd
, using Equation (3.202).
b) STEP 11.2—Calculate the final personnel injury consequence area, CA , using Equation (3.203).
f , inj
5.12 Determine the FC
5.12.1 General
The FC is determined accordance with the Level 1 consequence analysis; see Section 4.12.7.
5.12.2 Calculation of FC
The step-by-step procedure for estimating the impact of detection and isolation systems is in accordance with
Section 4.12.2.