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

RISK-BASED INSPECTION METHODOLOGY, PART 3—CONSEQUENCE OF FAILURE METHODOLOGY 3-37
vol
env
n
13
⋅
n
1
( −
evap )
C mass frac
= (3.91)
ρ
l
The final spill volume to be cleaned up is a probability weighted average of the spill volumes for each of the
release hole sizes. The probability weighting utilizes the generic frequencies of the release hole sizes provided
in Part 2, Table 3.1. The environmental cost to clean up the weighted spill volume is calculated using Equation
(3.92).
FC
f , environ
⎛
4
env
⎜∑
gffn⋅voln
⎟
n=
1
= ⎜
⎟⋅
⎜
⎝
gff
total
⎞
⎟
⎠
envcost
(3.92)
4.12.7 Calculation of FC
a) STEP 12.1—Calculate the cost (consequence in $) to repair the specific piece of equipment,
f , cmd
, using
Equation (3.84) with the release hole size damage costs from Table 4.15 and GFFs for the release hole
sizes from STEP 2.2. The material cost factor, matcost , is obtained from Table 4.16.
b) STEP 12.2—Calculate the cost of damage to surrounding equipment in the affected area, FC , using
f , affa
Equation (3.85) and component damage consequence area, CA , calculated in STEP 11.1. The
f , cmd
equipment cost factor, equipcost , is the unit equipment replacement cost in $/m 2 ($/ft 2 ).
c) STEP 12.3—For each release hole size, calculate the cost of business interruption due to the outage days
required to repair the damage to equipment.
1) Calculate the probability weighted repair of the specific piece of equipment using Equation (3.86) and
the downtime for each release hole size, Outage , from Table 4.17.
2) Calculate the downtime required to repair the surrounding equipment in the affected area, Outageaffa
, using Equation (3.87) and the cost of damage to the surrounding equipment in the affected area,
FC , calculated in STEP 12.2.
f , affa
3) Calculate the cost of business interruption, FC , using Equation (3.88). The production costs,
f , prod
prodcost , is the cost of lost production on the unit, $/day.
d) STEP 12.4—Calculate the costs associated with personnel injury using Equation (3.89) and the personnel
injury consequence area, CA , calculated in STEP 11.2. The unit population density, popdens , is the
f , inj
average number of personnel on the unit per m 2 (personnel/ft 2 ). The personnel injury cost,injcost , is the
cost incurred by the company as a result serious injury or fatality of personnel.
e) STEP 12.5—Calculate the costs associated with environmental cleanup.
3) Estimate the spill volume from each release hole size, using Equation (3.91), the release mass from
STEP 7.3, and the fluid liquid density and evaporation fraction obtained from Table 4.18.
n
FC