Fitness For Service (FFS)

Last update: Jan 13, 2017

Fitness for Service (FFS) is a best practice and standard used by the oil & gas and chemical process industries for in-service equipment to determine its fitness for continued service. FFS serves as a rational basis for defining flaw acceptance limits and allows engineers to distinguish between acceptable and unacceptable flaws and damage based on industry recognized and generally accepted good engineering practices (RAGAGEP).

The FFS of any particular material is determined by performing a fitness-for-service assessment per standardized methods and criteria. Performing accurate FFS evaluations is an integral aspect of fixed equipment asset integrity management as an alternative to using the original construction design code. The FFS of a piece of equipment may be viewed both in terms of current and future FFS or remaining life.

Most equipment can continue in service despite small flaws, and to repair or replace equipment that can still be used would be an unnecessary and costly expense. In addition, unnecessary weld repairs can do more harm than good and create unnecessary risks to personnel in many cases.

API RP 579-1/ASME FFS-1, Fitness for Service, Second Edition, is one example of a FFS methodology currently used by industry professionals. In general, most FFS assessment standards are broken into multiple levels. Each successive level (e.g., Levels 1, 2 and 3 of the referenced API 579-1/ASSME FFS-1 standard) requires increasing amounts of data, calculations, effort, and cost to arrive at the most accurate outcomes and possible longer equipment remnant life. In addition to calculations, FFS involves the consideration of additional data (e.g. pitting patterns and depths, corrosion morphology or shape and depth, crack depths and lengths, operating conditions, materials properties, etc.). Inspection information is often critical input to a FFS assessment.

 

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Calculating the Required Structural Thickness of Pipe Using Beam Stress Theory
November/December 2016 Inspectioneering Journal
By Nolan L. Miller at SASOL North America

This article will go through the methodology of each process that could be used in determining the structural component for the required pipe wall thickness, but will focus on the use of Beam Flexural Stress calculations and Beam Deflection calculations to determine the structural component of the required pipe wall thickness calculation.

November/December 2016 Inspectioneering Journal
By Michael Turnquist at Quest Integrity Group

This article exhibits how modern inspection methodologies combined with innovative computational analysis practices demonstrate the value of conducting fitness-for-service (FFS) assessments on sectional piping.

The Use of Miniature Test Specimens in  Fitness-for-Service Evaluation
May/June 2016 Inspectioneering Journal
By Douglas Marriott at Stress Engineering Services Inc., Shannon Read at Stress Engineering Services Inc., and Arun Sreeranganathan at Stress Engineering Services Inc.

Aging equipment, along with more aggressive service, makes it more important than ever to carry out fitness-for-service (FFS) assessments in support of run/repair/replace decisions. Testing material in the service-degraded condition enables quantification of the material condition and provides increased accuracy in FFS evaluations of these components.

Fitness for service: a powerful tool to keep your plant running safely
Partner Content

FFS assessment techniques are applicable to a wide range of damage types: LTA's, cracks, creep damage, dents, and more. These are very powerful analytical tools that often allow operators to not only keep the plant running, but to keep it running safely.

Fitness for service: a powerful tool to keep your plant running safely
Partner Content

FFS assessment techniques are applicable to a wide range of damage types: LTA's, cracks, creep damage, dents, and more. These are very powerful analytical tools that often allow operators to not only keep the plant running, but to keep it running safely.

Fired Heater Health Monitoring and  Reliability Management in Challenging Times
March/April 2016 Inspectioneering Journal
By Tim Hill at Quest Integrity Group

Achieving fired heater reliability in conjunction with meeting performance standards can be a challenging feat. Performance is a measure of the degree to which the fired heater is in an operable condition at any given time.

High Temperature Hydrogen Attack (HTHA): Life Assessment Methods for Carbon Steel and Carbon 0.50% Mo Materials
November/December 2015 Inspectioneering Journal
By Ralph E. King P.E. at Stress Engineering Services, Inc., and Brian Olson at Stress Engineering Services Inc.

To ensure the mechanical integrity and fitness-for-service (FFS) of equipment, facility managers, reliability engineers, and inspection technicians must understand the HTHA damage mechanism.

New API Inspector Certification Endorsement Program (ICEP)
November/December 2004 Inspectioneering Journal

Several new API inspection recommended practices exist in which inspectors need to be knowledgeable and qualified. This article details some of those standards.

Effective End of Useful Life Strategies for Pressure Equipment
July/August 2015 Inspectioneering Journal
By Greg Alvarado at Inspectioneering Journal

Asset managers need to know when repairs and replacement are required for many reasons, including safe operation, accurate budgeting, replacement planning, and on-going reliability. When predicting design life based on a simple, linear corrosion rate versus remaining thickness, metallurgical degradation, or crack propagation rates are often not accurate or realistic. Even if the models are good, things change.

In-Place Pipe Support Load Testing & Hanger Surveys – Part of a Best in Class Fitness-for-Service Program
July/August 2015 Inspectioneering Journal
By Lange Kimball at Stress Engineering Services, Joe Frey, PE at Stress Engineering, Inc., and Britt Bettell at Stress Engineering Services

This article introduces portions of a “Best-In-Class” Fitness-for-Service (FFS) program that includes the performance of regular visual inspections of pipe supports and hangers, coupled with in-situ load testing of suspect supports. This program can give the plant engineer the knowledge he needs to make sound operational and maintenance decisions.

Advances in Inspectability & Validation of Non-Metallic Composite Repair Systems
May/June 2015 Inspectioneering Journal
By David A. Hunter at Neptune Research, Inc.

In recent years, the growing use of composite repair systems for the rehabilitation of piping systems in the refining and chemical industries has increased the need for associated technologies for their manufacturing, installation, and inspection. One critical aspect of these repair systems is how to inspect and validate them for fitness for service. This article covers the testing completed for fiberglass and carbon fiber composite repair systems with specialty epoxy for full inspection capabilities.

Blog
March 16, 2015

For many years, it has been common practice in the petrochemical industry to use fitness-for-service (FFS) evaluations to determine whether or not a finding during an inspection would prevent a part from being able to be returned to service.

Blog
January 5, 2015

There are numerous benefits to adding fitness-for-service (FFS) assessments to energy sector reliability projects. The acceptance of API 579/ASME FFS-1 is increasing across the energy sector and other industries, as these benefits have been demonstrated in a wide range of projects.

Blog
December 22, 2014

One of Inspectioneering's most popular topics is Fitness for Service (FFS). This blog post will provide you with some highlights from some of our most popular articles related to FFS. It's only a small sample of what we offer, but it should still prove useful to readers both old and new.

Stress Assisted Corrosion and Fitness for Service in 66 Year Old Boilers
September/October 2014 Inspectioneering Journal
By Amanda Nurse at BP, John Companik at BP, and Scott Vest at BP

Maintaining mechanical integrity for aging power boilers can be challenging. This article provides a case study on how mitigating one damage mechanism led to the discovery of another, and how refinery engineers collaborated with industry experts to fully understand an unfamiliar damage mechanism and perform a fitness for service assessment for the safe and reliable operation of power boilers.

Fitness for Service from an RBI Point of View
May/June 2014 Inspectioneering Journal
By Luciano Narcisi at GIE

As an RBI consultant, I frequently get involved in discussions spawned from a misunderstanding of the relation between Risk Based Inspection (RBI) approaches and Fitness for Service (FFS) assessments. Questions like: If thickness is below the minimum required by design, why does the risk stay so low?

May/June 2014 Inspectioneering Journal
By Hugo Julien, P.E. at GCM Consultants, Serge Bisson at GCM Consultants, and Guy St-Arneault, P.E. at GCM Consultants

Inspections, repairs, modifications, or Fitness-For-Service (FFS) assessments on an old, unfired ASME Section VIII (Div. 1) pressure vessel - Which ASME Section VIII (Div. 1) Code Edition should you use?