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

PART 1—INTRODUCTION TO RISK-BASED INSPECTION METHODOLOGY 1-25
a
b
is a variable provided for reference fluids for Level 1 COF analysis
is a variable provided for reference fluids for Level 1 COF analysis
C f is the COF, m 2 (ft 2 ) or $
CA f is the consequence impact area, m 2 (ft 2 )
fin
CA f
is the financial consequence, $
flam
CA f
is the flammable consequence impact area, m 2 (ft 2 )
flam
CA
f ,n is the flammable consequence impact area for each hole, m 2 (ft 2 )
D f (t)
is the DF as a function of time, equal to D f-total evaluated at a specific time
thin
D f is the DF for thinning
D f-total
F MS
is total DF for POF calculation
is the management systems factor
FC is the financial consequence, $
gff
gff n
gff total
k
P f (t)
P f (t,I E )
P s
R
R(t)
R(t,I E )
t min
X
ß
η
is the GFF, failures/year
is the GFF for each of the n release hole sizes selected for the type of equipment being
evaluated, failures/year
is the sum of the individual release hole size generic frequencies, failures/year
is the release fluid ideal gas specific heat capacity ratio, dimensionless
is the POF as a function of time, failures/year
is the POF as a function of time and inspection effectiveness, failures/year
is the storage or normal operating pressure, kPa (psi)
is the universal gas constant = 8314 J/(kg-mol)K [1545 ft-lbf/lb-mol°R]
is the risk as a function of time, m 2 /year (ft 2 /year) or $/year
is the risk as a function of time and inspection effectiveness, m 2 /year (ft 2 /year) or $/year
is the minimum required thickness, mm (in.)
is the release rate or release mass for a Level 1 COF analysis, kg/s [lb/s] or kg [lb]
is the Weibull shape parameter
is the Weibull characteristic life parameter, years