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

RISK-BASED INSPECTION METHODOLOGY, PART 3—CONSEQUENCE OF FAILURE METHODOLOGY 3-33
Note that since the component damage consequence areas for toxic releases,
tox
CA , and nonflammable,
cmd
nontoxic releases, , are both equal to zero, the final component damage consequence area is equal to
nfnt
CA
cmd
the consequence area calculated for flammable releases,
flam
CA .
cmd
CA
= CA
(3.80)
flam
f , cmd f , cmd
4.11.3 Final Personnel Injury Consequence Area
The final personnel injury consequence area is:
flam tox nfnt
CAinj = max ⎡
⎣CAf , inj
, CAf , inj
, CA ⎤
f , inj ⎦
(3.81)
4.11.4 Final Consequence Area
The final consequence area is:
CAf = max ⎡
⎣CAf , cmd
, CA ⎤
f , inj ⎦
(3.82)
4.11.5 Calculation of Final Consequence Area
a) STEP 11.1—Calculate the final component damage consequence area, CA , using Equation (3.80).
f , cmd
b) STEP 11.2—Calculate the final personnel injury consequence area, CA , using Equation (3.81).
f , inj
c) STEP 11.3—Calculate the final consequence area, CA
f
, using Equation (3.82).
4.12 Determine the FC
4.12.1 Overview
There are many costs associated with any failure of equipment in a process plant. These include, but are not
limited to:
a) cost of equipment repair and replacement;
b) cost of damage to surrounding equipment in affected areas;
c) costs associated with production losses and business interruption as a result of downtime to repair or
replace damaged equipment;
d) costs due to potential injuries associated with a failure;
e) environmental cleanup costs.
The approach used is to consider the above costs on both an equipment specific basis and an affected area
basis. Thus, any failure (loss of containment) has costs associated with it, even when the release of the
hazardous material does not result in damage to other equipment in the unit or serious injury to personnel.
Recognizing and using this fact presents a more realistic value of the consequences associated with a failure.
The FC of a loss of containment and subsequent release of hazardous materials can be determined by adding
up the individual costs discussed above: