Fitness-for-service (FFS) and engineering critical assessment (ECA) of pipelines and structures (3 days)

This course focuses on the practical application of FFS and ECA particularly for pipelines and structures.

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Norway Training Courses

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Training Information

  • Duration:

    3 days

  • Delegate info:

    NOK 19,500

  • Additional information:

    Kindly note that seats are limited and early registration would be appreciated. As a corporate scheme, 3 or more candidates from the same company would be entitled to discount of 25% as a group rebate. Deadline for enrollment: One week before course start.

  • In-house training:

    We can also conduct a customized in-house training course at your office as required.

Course dates

 Autumn 2019 - TBA
3 days
Høvik, Norway
NOK 19 500
Jens P. Tronskar


Codes for design and construction of pressure vessels, pipelines, offshore structures, bridges and buildings, process plants etc. contain acceptance criteria that are based on workmanship standards that may be somewhat arbitrary. 

During the construction phase or in service, there may be situations where materials properties or observed defects do not meet the strict code requirements. In such cases a fitness‐for‐service (FFS) or engineering critical assessment (ECA) can be applied. Such an approach is nowadays becoming accepted by many codes as it is recognized that the requirements or acceptance criteria inherent in the codes may be unnecessarily conservative. 

Using this alternative approach it can be shown that the structure or component can be acceptable if the conditions for failure are not reached within its service life when subjected to many possible damage or degradation mechanisms including brittle and ductile fracture, fatigue, environmental assisted cracking and creep at higher temperatures. 

There are now several publications and recommended practices available that describe the FFS and ECA approaches:

Course objective and scope

DNV GL has developed a course programme focusing on the practical application of FFS and ECA particularly for pipelines and structures. BS7910 and API579 are essentially stress-based codes, however, the course also covers strain-based analyses of pipelines with girth weld flaws. It also provides an overview of different methods and software tools for analyzing the tensile strain capacity of pipelines subject to high strain. In addition, the course covers a brief introduction of finite element analysis (FEA) to determine the stress and strain input to the analysis and advanced flaw modelling and J‐integral analysis to derive the crack driving force and limit loads.

The course will cover the theoretical background for elastic and elastic plastic fracture mechanics and the fracture assessment diagram (FAD) methods, fatigue crack growth and tearing analysis. The course will also give insight into the practical aspects of elastic‐ plastic fracture toughness (CTOD, J-integral) testing of weldments and the requirements to non‐destructive testing for flaw sizing and development of alternative flaw acceptance criteria for pipeline installation.

The first three days (days 1‐3) of the course cover applications involving high strain due to lateral buckling, reeling installation and high temperatures in clad pipelines as well as effect of fatigue loading due to vortex induced vibration (VIV) associated with free spans. An optional fourth day (day 4) of the course covers an introduction of finite element modelling, definition of boundary conditions and material models and finite element based fracture mechanics analysis to generate stress/strain input to general design and ECA/FFS assessments.

Learning objective

It is intended that the participants attending this course shall become confident in performing Option 1 and 2 analyses according to BS7910: 2013 and that they also will be introduced to Option 3, which uses numerical analysis to generate a FAD and ductile tearing assessments. The participants will also become familiar with strain based analyses based on DNVGL-RP-F108 : 2017 and alternative methods. 

Target group

The course is aimed at welding and inspection, structural, mechanical, construction, design and maintenance engineers who require more knowledge of the application of fitness‐for‐purpose assessment methods for structures, piping/pipelines and pressure vessels.

The lecturer

Find more about Jens P. Tronskar, Senior Vice President and Chief Technology Officer of DNV GL's Oil & Gas Technology Centre in Singapore.

Jens P. Tronskar - w100pxl

Course agenda

Day 1

  • Time
  • 09:00 -10:45

    Offshore and onshore pipeline design, construction, installation, operation and maintenance philosophy. 

    Introduction to elastic and elastic plastic fracture mechanics.

  • 11:00 -13:30

    Fracture toughness testing of weldments.

    Demonstration of fracture toughness testing in the DNV GL laboratory.

  • 15:00 -16:30

    Significance of flaws in pipelines and structures 

    Fracture mechanics parameters, fatigue, fracture (reference to BS 7910:2013, defect assessments as per (ASME B31.8, API 579 etc.) 

    Assessments for crack-like defects based on failure assessment diagram approach 

    Assessment of non-crack-like defects for Option 1, 2 and 3.

Day 2

  • Time
  • 08:00 -10:45

    ECA for pipeline installation 

    Derivation of alternative flaw acceptance criteria as per DNVGL‐RP‐F108 Assessment of flaws in pipeline and riser girth welds, 2017.  

    Overview of strain based analyses/methods and software tools to derive tensile strain capacity of girth welds with flaws.

  • 11:00 -14:00

    Assessment of non-planar defects (corrosion)

    DNVGL‐RP‐F101 (2017), BS7910, API 579

  • 14:00 -16:30

    Non‐destructive testing (ILI, TOF, TOFD, EMA). Pipeline AUT (videos) 

    Flaw sizing for pipeline installation and fitness‐for‐purpose assessments 

    FFS/ECA software introduction.

Day 3

  • Time
  • 08:00 -12:00

    Case studies 

    Hands-on training”where the participants run the analyses using appropriate commercially available and specially developed software programs.  

    Case 1: Gas pipeline with external longitudinal flaw in seam weld  

    Case 2: Gas pipeline with fabrication induced seam weld flaws.

  • 13:00 -14:00

    Case 3: Gas pipeline with flaws in girth weld, failure assessment option 1, 2 and 3  

    Case 4: Assessment of pipeline with CO2 corrosion 

    Case 5: ECA to develop AUT flaw acceptance criteria for pipeline girth welds for pipeline installation.

  • 14:00 -15:30

    Case 6: ECA to develop AUT flaw acceptance criteria for pipeline girth welds for pipeline installation, lateral buckling 

    Case 7:  Accounting for free-spans exceeding tolerable span lengths and vortex induced vibration (VIV)  

    Case 8:  ECA case for pipeline reeling involving large strain 

    Comments and questions.