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

CONTENTS
1 SCOPE .................................................................................................................................................. 1
2 REFERENCES ...................................................................................................................................... 1
2.1 Normative ..................................................................................................................................... 1
2.2 Informative ................................................................................................................................... 1
3 PROBABILITY OF FAILURE (POF) METHODOLOGY ....................................................................... 9
3.1 Overview ....................................................................................................................................... 9
3.2 Calculation of POF ....................................................................................................................... 10
3.3 Generic Failure Frequency (GFF)............................................................................................... 10
3.4 Damage Factor (DF)..................................................................................................................... 11
3.4.1 Overview ............................................................................................................................... 11
3.4.2 DF Combination for Multiple Damage Mechanisms ......................................................... 11
3.4.3 Inspection Effectiveness Category .................................................................................... 12
3.5 Management Systems Factor ..................................................................................................... 13
3.5.1 General .................................................................................................................................. 13
3.5.2 Overview ............................................................................................................................... 13
3.5.3 Auditing Technique ............................................................................................................. 14
3.5.4 Calculation of the Management Systems Factor .............................................................. 14
3.6 Nomenclature ............................................................................................................................... 15
3.7 Tables............................................................................................................................................ 16
4 THINNING DF ....................................................................................................................................... 19
4.1 Scope ............................................................................................................................................ 19
4.2 Screening Criteria ........................................................................................................................ 19
4.3 Required Data .............................................................................................................................. 19
4.4 Basic Assumptions ..................................................................................................................... 19
4.5 Determination of the DF .............................................................................................................. 20
4.5.1 Overview ............................................................................................................................... 20
4.5.2 Corrosion Rate ..................................................................................................................... 20
4.5.3 Corrosion Rate Confidence Levels .................................................................................... 20
4.5.4 Thinning Type ...................................................................................................................... 21
4.5.5 Thickness and Age .............................................................................................................. 21
4.5.6 Inspection Effectiveness ..................................................................................................... 22
4.5.7 Calculation of Thinning DF ................................................................................................. 22
4.6 Nomenclature ............................................................................................................................... 26
4.7 Tables............................................................................................................................................ 29
4.8 Figures .......................................................................................................................................... 36
5 COMPONENT LINING DF .................................................................................................................... 37
5.1 Scope ............................................................................................................................................ 37
5.2 Screening Criteria ........................................................................................................................ 37
5.3 Required Data .............................................................................................................................. 37
5.4 Basic Assumptions ..................................................................................................................... 37
5.5 Determination of the DF .............................................................................................................. 37
5.5.1 Overview ............................................................................................................................... 37
5.5.2 Inspection Effectiveness ..................................................................................................... 38
5.5.3 Calculation of the DF ........................................................................................................... 38
5.6 Nomenclature ............................................................................................................................... 38
5.7 Tables............................................................................................................................................ 39