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API 579-1/ASME FFS-1 - Fitness-For-Service (FFS)

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API 579-1/ASME FFS-1, Fitness-For-Service, Third Edition, is a standard developed and published jointly by the American Petroleum Institute (API) and ASME. It describes several fitness-for-service (FFS) assessment techniques that help ensure the safe and reliable operation of pressurized equipment used in oil & gas, petrochemical, and chemical facilities. The latest edition was published in June of 2016.

API 579-1/ASME FFS-1 provides procedures for performing proper fitness-for-service assessments and/or rerating of equipment that is designed and constructed to recognized codes and standards. This standard contains numerous sections on assessment procedures for calculating the impact of damage mechanisms such as brittle fracture, general metal loss and local metal loss, pitting corrosion, blisters and laminations, weld misalignment and shell distortion, crack-like flaws, creep damage, and fire damage.

This standard has procedures for evaluating several different types of equipment (pressure vessels, piping, and tankage) that may contain flaws or damage. These include the evaluation and rerating of pressure vessels designed based on the the ASME Boiler and Pressure Vessel Code, and piping systems that were constructed to either the ASME B31.3 Piping Code or those constructed under API 650 and 620, along with pressure containing equipment constructed to any other codes that are recognized in the publication.

It covers both the present integrity of the component, given a current state of damage, and the projected remaining life. Qualitative and quantitative guidance for establishing remaining life and in-service margins for continued operation of equipment are provided in regards to future operating conditions and environmental compatibility. The procedures are not intended to provide a definitive guideline for every possible situation that may be encountered. However, flexibility is provided to the user in the form of an advanced assessment level to handle uncommon situations that may require a more detailed analysis.

API 579-1/ASME FFS-1 also has appendices on several other important topics, such as equations for determining MAWP, thickness, and stress in components, methods of stress analysis for Level 2 and Level 3 FFS assessments, a compendium of stress intensity solutions, guidance on material properties, failure modes and damage mechanisms, validation of assessment procedures, and information on submitting technical inquiries to API, among other things.

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