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

3-128 API RECOMMENDED PRACTICE 581
pvcedi vn ,
VCE
Vapor Release
poi vn ,
Ignition
( 1−
poiivn
, )
Delayed Ignition
poii vn ,
Immediate Ignition
Flame Front Fast
( )
1−
pvcedivn
,
Flame Front Slow
Flash Fire
Fireball
( 1−
poivn
, )
No Ignition
Physical Explosion or Toxic Event
Liquid Release
poi ln ,
Ignition
( 1−
poiln
, )
( 1−
poiiln
, )
Delayed Ignition
poii ln ,
Immediate Ignition
pvcedi ln ,
Flame Front Fast
( 1−
pvcediln
, )
Flame Front Slow
VCE
Flash Fire
Pool Fire
No Ignition
Safe Dispersion 1
( 1−
poii2,
n )
Delayed Ignition
pvcedi 2,n
Flame Front Fast
( 1−
pvcedi2,
n )
VCE
Flash Fire
poi 2,n
Ignition
Flame Front Slow
pfbii 2r
Fireball
Two-Phase Release
poii 2,n
Immediate Ignition
( − pfbii )
1
2r
Pool Fire
( 1−
poi2,
n )
No Ignition
BLEVE or Toxic Event
1
If released fluid is toxic, or could result in steam burns or acid splashes, these consequences are considered before a safe dispersion.
Figure 5.4—Level 2 Consequence Analysis Event Tree for Rupture Case