scope:

FOREWORD

In contrast to the straightforward and conservative calculations that are typically found in design codes, more sophisticated assessment of metallurgical conditions and analyses of stresses and strains can more precisely indicate whether operating equipment is fit for its intended service or whether fabrication defects or in-service deterioration threaten its integrity. Such analyses offer a sound basis for decisions to continue to run as is or to alter, repair, monitor, retire or replace the equipment.

The publication of the American Petroleum Institute's Recommended Practice 579, Fitness-For-Service, in January 2000 provided the refining and petrochemical industry with a compendium of consensus methods for reliable assessment of the structural integrity of equipment containing identified flaws or damage. API RP 579 was written to be used in conjunction with the refining and petrochemical industry's existing codes for pressure vessels, piping and aboveground storage tanks (i.e., API 510, API 570 and API 653). The standardized Fitness-For-Service Assessment procedures presented in API RP 579 provide technically sound consensus approaches that ensure the safety of plant personnel and the public while aging equipment continues to operate and can be used to optimize maintenance and operation practices, maintain availability and enhance the long-term economic performance of plant equipment.

API RP 579 was prepared by a committee of the American Petroleum Institute with representatives of the Chemical Manufacturers Association, as well as some individuals associated with related industries. It grew out of a resource document developed by a Joint Industry Program on Fitness-For-Service administered by The Materials Properties Council. Although it incorporated the best practices known to the committee members, it was written as a Recommended Practice rather than as a mandatory standard or code.

While API was developing Fitness-For-Service methodology for the refining and petrochemical industry, the American Society of Mechanical Engineers (ASME) also began to address post-construction integrity issues. Realizing the possibility of overlap, duplication, and conflict in parallel standards, ASME and API formed the Joint Fitness-For-Service Committee in 2001 to develop and maintain a Fitness-For-Service standard for equipment operated in a wide range of process, manufacturing, and power generation industries. It was intended that this collaboration would promote the widespread adoption of these practices by regulatory bodies. The Joint Committee included the original members of the API Committee that were involved in the development of API Recommended Practice 579, complemented by a similar number of ASME members representing similar areas of expertise in other industries such as chemicals, power generation, and pulp and paper. In addition to owner representatives, it included substantial international participation and subject matter experts from universities and consulting firms.

In June 2007, the API and ASME Fitness-For-Service Joint Committee published the first edition of API 579-1/ASME FFS-1 Fitness-For-Service. The main enhancement in this publication relative to 2000 Edition API 579 was the addition of Part 10 covering the assessment of components operating in the creep range.

The 2016 Edition of API 579-1/ASME FFS-1 included many modifications and technical improvements. Some of the more significant changes are the following: reorganized the standard to facilitate use and updates by renumbering annexes that are directly associated with the relevant part of the document, Expanded equipment design code coverage, added a new annex for establishing an allowable Remaining Strength Factor (RSF), re-wrote weld residual stress solution annex for use in the assessment of crack-like flaws, updated guidance on material toughness predictions for use in the assessment of crack-like flaws, updated evaluation procedures for the assessment of creep damage, added an annex covering metallurgical investigation and evaluation of mechanical properties in a fire damage assessment, and developed new Part 14 covering the assessment of fatigue damage.

Numerous changes have been made for the 2021 Edition of API 579-1/ASME FFS-1 to address user feedback and to introduce new technology. A summary of these changes is provided on pages xxxv to xl.