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

Risk-Based Inspection Methodology
Part 3—Consequence of Failure Methodology
1 Scope
The calculation of the consequence of a leak or rupture of a component is covered in this document. This
document is Part 3 of a three-volume set presenting the API 581 Risk-Based Inspection methodology. The
other two Parts are Part 1—Inspection Planning Methodology and Part 2—Probability of Failure Methodology.
The COF methodology presented in Part 3 determines the COF that is used with the POF (Part 2) to provide
a risk ranking and inspection plan (Part 1) for a component subject to process and environmental conditions
typically found in the refining, petrochemical, and exploration and production industries. The consequence
calculated using the procedures in Part 3 is not intended to be used in a rigorous consequence analysis of a
component, such as might be employed during unit design, equipment siting, and for other safety purposes.
However, the methods provided for the Level 2 COF are consistent with these approaches.
2 References
2.1 Normative
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced document
(including any amendments) applies.
API Standard 520, Part 1—Sizing, Selection, and Installation of Pressure–relieving Devices
API Recommended Practice 581, Risk-Based Inspection Methodology, Part 1—Inspection Planning
Methodology
API Recommended Practice 581, Risk-Based Inspection Methodology, Part 2—Probability of Failure
Methodology
API Recommended Practice 581, Risk-Based Inspection Methodology, Part 5—Methodology for Special
Equipment
2.2 Informative
[1] Crowl, D.A., and J.F. Louvar, Chemical Process Safety: Fundamentals with Applications, ISBN 0-13-
129701-5, Prentice Hall, 1990.
[2] ASTM C1055, Standard Guide for Heated System Conditions that Produce Contact Burn Injuries,
American Society for Testing Materials, 2014.
[3] DIPPR 801 Database, AIChE, November 2008.
[4] Leung, J.C., Easily Size Relief Devices and Piping for Two-Phase Flow, Chemical Engineering Progress,
92(12), December 1996, pp. 28–50.
[5] Kletz, T.A., Unconfined Vapor Cloud Explosions, AIChE Loss Prevention, 11, p. 50, 1977.
[6] Woodward, J.L., Estimating the Flammable Mass of a Vapor Cloud, ISBN 0-8169-0778-1, Center for
Chemical Process Safety, American Institute of Chemical Engineers, 1999.
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