Fit for Service Assessments

Critical engineering structures normally require an assessment of the damage tolerance of their components to various forms of degradation (i.e. material loss owing to corrosion and/or cracking).


Cracking can be introduced into the structure due to material manufacturing processes (laminations), fabrication (weld defects) or as the result of the in service loading sustained by the components of the structure (fatigue/fracture). Assessment procedures are normally employed to assess parameters such as remaining life, critical crack length, leak before break, inspection intervals, etc. to ascertain whether the component is “fit” for its intended environment and service loadings.


Wayland Engineering Ltd. maintains the expertise to perform various levels of “fit for service” assessments for critical engineering structures.


Some specific aspects of fitness for service Wayland Engineering has experience with includes:

  • Brittle Fracture Assessments

  • Fire Damage Assessments

  • General Thinning, Local Thinning, and Pitting Damage Assessments

  • Crack-Like Flaw Damage Assessments

  • Wet H2S and Lamination Damage Assessments

  • Dents, Gouges, Weld Misalignment, and Shell Distortion Assessments

  • Creep Damage Assessments

  • Fatigue Damage Assessments

Example of a Failure Assessment Diagram (FAD)

Typical Failure Assessment Diagram (FAD)

Example results from an API 579 Part 3 (Brittle Fracture) Level 1 Assessment

Screening Assessments using API 579 / ASME FFS-1 Methodologies

Finite Element Analysis of a furnace elbow experiencing a bending moment

Finite Element Analysis Capabilities

Brittle Fracture Assessments

Brittle fracture failures can be sudden and catastrophic. Pressure vessels, piping, and steel structures need assessment to ensure that they are not at risk of failure during cold winter months and equipment commissioning.

Equipment built to ASME VIII Division 1 prior to the 1987 Addenda are at particular risk, as the code previously had no required restrictions on notch toughness.

Wayland Engineering can screen equipment to API 579 Part 3 and generate Minimum Pressurization Temperature (MPT) curves to multiple standards including API 934F for heavy wall reactors operating in high temperature hydrogen service.

Minimum Pressurization Curve for a heavy wall reactor per API 934F methodology

MPT Curve for Heavy Wall Reactor Considering the Effects of Dissolved Hydrogen

Fire Damage Assessments

No matter how careful assets are designed and operated, fires can unfortunately still happen. All staff members at Wayland Engineering have experience with Fire Damage Assessments, including the ability to perform Field Metallurgical Replication (also known as in-situ metallography) & portable hardness testing.

Wayland Engineering can provide fire damage assessment maps overlaid on existing client site plot plans or satellite imagery. Fire damage maps are then used to provide inspection, assessment, repair, and replacement recommendations for pressure equipment and piping.

Plot plan map overlaid with a fire assessment damage map

Fire Assessment Map Overlaid on a Site Plot Plan

Creep Assessments

High temperature components have a limited design service life. Operating beyond this initial design or outside normal operating parameters can be safely accomplished by performing creep life assessments.

Wayland Engineering has extensive experience performing creep life assessments and Omega Testing of materials. Results can be provided in any form that the client desired including tabular, graphical, and 3D models.

Predicted remaining life of furnace tubes overlaid on an interactive model

Creep Remaining Life Overlaid on Furnace Tube Model