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

RISK-BASED INSPECTION METHODOLOGY, PART 3—CONSEQUENCE OF FAILURE METHODOLOGY 3-117
MW
n
v
is the release fluid molecular weight, kg/kg-mol (lb/lb-mol)
is the moles that flash from liquid to vapor upon release to atmosphere, kg-mol (lb-mol)
pfball
n
is the probability of a fireball given a release associated with the n th release hole size
pfball is the probability of a fireball given a vapor release associated with the n th release hole size
vn ,
pfbii
pffdi
is the probability of fireball given an immediate ignition of a vapor or two-phase instantaneous
release
is the probability of flash fire given a delayed ignition
pffdi is the probability of flash fire given a delayed ignition of a release of a flammable liquid
ln ,
associated with the n th release hole size
pffdi is the probability of flash fire given a delayed ignition of a release of a flammable vapor
vn ,
associated with the n th release hole size
pflash
n
is the probability of a flash fire given a release associated with the n th release hole size
pflash is the probability of a flash fire given a vapor release associated with the n th release hole size
vn ,
pjet
n
is the probability of a jet fire given a release associated with the n th release hole size
pjet is the probability of a jet fire given a vapor release associated with the n th release hole size
vn ,
pnfnt
n
poi
is the probability of nonflammable, nontoxic event given a release associated with the n th hole
size
is the probability of ignition given a release
ait
poi
l
is the maximum probability of ignition for a liquid release at or above the AIT
ait
poi
v
is the maximum probability of ignition for a vapor release at or above the AIT
poi is the probability of ignition given a liquid release at ambient temperature associated with the n th
amb
ln ,
release hole size
poi is the probability of ignition given a vapor release at ambient temperature associated with the
amb
vn ,
n th release hole size
poi is the probability of ignition given a liquid release associated with the n th release hole size
ln ,
poi is the probability of ignition given a vapor release associated with the n th release hole size
vn ,