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

4.6.5 Releases to the Environment ............................................................................................... 16
4.6.6 Calculation for Detection and Isolation ............................................................................... 16
4.7 Determine the Release Rate and Mass for COF ......................................................................... 16
4.7.1 Continuous Release Rate ..................................................................................................... 17
4.7.2 Instantaneous Release Mass ................................................................................................ 17
4.7.3 Calculation of Release Rate and Mass ................................................................................ 17
4.8 Determine Flammable and Explosive Consequence ................................................................. 17
4.8.1 Overview ................................................................................................................................. 17
4.8.2 Consequence Area Equations .............................................................................................. 18
4.8.3 Adjustment of Consequence Areas to Account for Mitigation Systems ......................... 19
4.8.4 Adjustment of Consequence Areas for Energy Efficiencies ............................................. 19
4.8.5 Blending of Results Based on Release Type ...................................................................... 19
4.8.6 Blending of Results Based on AIT ....................................................................................... 20
4.8.7 Determination of Final Flammable Consequence Areas ................................................... 20
4.8.8 Calculation of Consequence Area ....................................................................................... 21
4.9 Determine Toxic Consequence .................................................................................................... 25
4.9.1 General .................................................................................................................................... 25
4.9.2 Common Refining Toxic Materials ....................................................................................... 25
4.9.3 Common Chemical Industry Toxic Materials ...................................................................... 25
4.9.4 Representative Fluids for Toxic Mixtures ........................................................................... 25
4.9.5 Determination of the Toxic Release Rate and Mass .......................................................... 26
4.9.6 Estimation of Toxic Consequence Area for HF Acid and H 2S ........................................... 26
4.9.7 Estimation of Toxic Consequence Area for Ammonia and Chlorine ............................... 27
4.9.8 Estimation of Toxic Consequence Area for Additional Common Chemicals.................. 27
4.9.9 Material Concentration Cut-off ............................................................................................. 28
4.9.10 Release Duration .................................................................................................................... 28
4.9.11 Toxic Outcome Probabilities ................................................................................................ 28
4.9.12 Consequence of Releases Containing Multiple Toxic Chemicals .................................... 29
4.9.13 Effects of Mitigation Measures on Toxic Releases ............................................................ 29
4.9.14 Determination of Final Toxic Consequence Areas ............................................................. 29
4.9.15 Calculation of Toxic Consequence Areas ........................................................................... 29
4.10 Determine Nonflammable, Nontoxic Consequence ................................................................... 30
4.10.1 General .................................................................................................................................... 30
4.10.2 Consequence of Steam Leaks .............................................................................................. 30
4.10.3 Consequences of Acid and Caustic Leaks ......................................................................... 31
4.10.4 Blending of Results Based on Release Type ...................................................................... 31
4.10.5 Determination of Final Nonflammable, Nontoxic Consequence Areas ............................ 31
4.10.6 Calculation of Nonflammable, Nontoxic Consequence Areas .......................................... 32
4.11 Determine the Component Damage and Personnel Injury Consequence Areas .................... 32
4.11.1 Overview ................................................................................................................................. 32
4.11.2 Final Component Damage Consequence Area ................................................................... 32
4.11.3 Final Personnel Injury Consequence Area ......................................................................... 33
4.11.4 Final Consequence Area ....................................................................................................... 33
4.11.5 Calculation of Final Consequence Area .............................................................................. 33
4.12 Determine the FC ........................................................................................................................... 33
4.12.1 Overview ................................................................................................................................. 33
4.12.2 Component Damage Cost ..................................................................................................... 34
4.12.3 Damage Costs to Surrounding Equipment in Affected Area ............................................ 34
4.12.4 Business Interruption Costs ................................................................................................. 35
4.12.5 Potential Injury Costs ............................................................................................................ 35
4.12.6 Environmental Cleanup Costs .............................................................................................. 36
4.12.7 Calculation of FC ................................................................................................................... 37
4.13 Nomenclature ................................................................................................................................. 38