API 579 / ASME FFS-1 Fitness-For-Service (FFS) is performed to ensure integrity when equipment is found to contain a flaw, or damage.

Historical Background of API 579 /ASME FFS-1

1990: Joint industry project was organized by the Materials Properties Council (MPC) to develop FFS guidelines for the refining industry
2000: Based on the MPC final report, API issued API-579 recommended practice for FFS Assessment, which was welcomed by both refinery and non-refinery industries
2007: ASME joined forces with API and issued API 579-1/ASME FFS-1 Standard Contents of API 579-Code Parts

Parts of the (2000) API 579

1 – Introduction
2 – FFS Engineering Evaluation Procedure
3 – Brittle Fracture
4 – General Metal Loss
5 – Localized Metal Loss
6 – Pitting Corrosion
7 – Blisters, HIC, and SOHIC Damage
8 – Weld Misalignment and Shell Distortions
9 – Crack-Like Flaws
10 – Equipment Operating in the Creep Range
11 – Fire Damage


Inspections of a pressure vessel, tank, or related equipment should be performed on a regular basis to ensure their continued operation is safe. When equipment is found to contain a flaw, or damage, Fitness-For-Service (FFS) assessments are performed to demonstrate structural integrity. API 579 / ASME FFS-1 provides guidance for conducting FFS assessments, specifically prepared for pressurized equipment.

Fitness-for-service evaluations performed in accordance with this Standard are recognized and referenced by API 510 (Pressure Vessel Inspection Code), API 570 (Piping Inspection Code), API 653 (Tank Inspection, Repair, Alteration, and Reconstruction), and by NB-23 (National Board Inspection Code) as suitable for evaluating the structural integrity of pressure vessels and related equipment.


(1) “An Overview of API 579-1/ASME FFS-1 Fitness-For-Service Assessment Standard with Applications to Case Studies” Mohammad M. Megahed & Mohammad S. Attia, Faculty of Engineering – Cairo University – Egypt, 3rd International Conference in Africa and Asia, Welding and Failure Analysis of Engineering Materials, 2-5 November 2015, Luxor, Egypt
(2) Fitness-For-Service Assessment Procedures API 579/BS 7910 (https://www.twi-global.com/technical-knowledge/published-papers/which-procedures-for-fitness-for-service-assessment-api-579-or-bs-7910-july-2003)

Resources on Fitness for Service

API 579: A Comprehensive Fitness-For-Service Guide (International Journal of Pressure Vessels and Piping)


Image of Ash Silo for API 579-1 / ASME-1 Fitness for Service

We performed an API 579-1/ASME FFS-1 Fitness For Service Evaluation of a 40 year old ash silo (approximately 38-foot diameter x 64-foot tall).

In addition to performing Fitness for Service Evaluations – we also provide engineering to API Codes including 510, 570, 653.


– Fitness For Service on a Brewery Tank
– Fitness For Service on a Urea Reactor
– Fitness For Service on Overheated Boiler Tubes


(412) 835-5007

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