Time of Flight Diffraction (TOFD)

Introduction

Time of Flight Diffraction (TOFD) is one of the most advanced and highly accurate ultrasonic inspection techniques used for detecting, sizing, and characterizing weld defects and internal discontinuities. Unlike conventional UT and PAUT, TOFD relies on diffracted sound waves from crack tips, providing exceptional accuracy in flaw sizing — often within ±1 mm.

TOFD is widely used in Oil & Gas, Petrochemical, Power Generation, Pipeline Construction, Pressure Vessel Fabrication, Marine, and Structural Integrity Assessment. It is considered a critical technique for high‑risk assets and is frequently required in API, ASME, and ISO‑based inspection programs.

This GTMCS Time of Flight Diffraction (TOFD) program provides advanced training in TOFD physics, probe setup, scanning techniques, data interpretation, and code‑based acceptance criteria. The course is aligned with ISO 9712, ASNT SNT‑TC‑1A, and international best practices.

This training course will highlight:

• TOFD principles, diffraction theory & wave behavior
• Probe setup, wedge selection & focal depth
• A‑scan, B‑scan & D‑scan interpretation
• Weld flaw detection & accurate sizing
• Acceptance criteria from ASME, API, ISO

Course Benefits

• Master advanced TOFD inspection techniques
• Detect & size cracks with high accuracy
• Interpret TOFD scans confidently
• Enhance asset integrity & weld quality assurance
• Prepare for ISO 9712 / ASNT certification
• Increase employability in advanced NDT roles

Tools & Technologies Covered

• TOFD flaw detectors & scanners
• Longitudinal & shear wave probes
• Wedges, encoders & scanning frames
• TOFD software for imaging & analysis
• Digital data acquisition & reporting tools

Practical Workshops

• TOFD equipment setup & calibration
• Probe alignment & wedge delay calibration
• A‑scan, B‑scan & D‑scan interpretation
• Weld flaw detection & tip diffraction sizing
• Level II evaluation & reporting simulation

Real‑World Case Studies

• Pipeline girth weld TOFD inspection
• Pressure vessel & tank weld evaluation
• Structural steel & offshore TOFD
• Crack sizing in high‑risk components
• Shutdown/turnaround TOFD operations

Industry Relevance

This course is essential for:

• Oil & Gas & Petrochemical inspectors
• Pipeline & welding inspection teams
• Mechanical, civil & structural inspectors
• Marine & offshore inspection teams
• Advanced NDT & asset integrity specialists

Future Skills Alignment

• Advanced ultrasonic diffraction competency
• Digital NDT & data interpretation
• Crack sizing & flaw characterization
• Technical reporting & documentation
• Foundation for AUT & advanced UT systems

Objectives

By the end of this training course, participants will be able to:

• Perform TOFD inspections to Level II competency
• Interpret A‑scan, B‑scan & D‑scan images
• Apply acceptance criteria from ASME, API, ISO
• Detect & size cracks with high accuracy
• Prepare advanced TOFD inspection reports
• Pass ISO 9712 / ASNT TOFD certification exams

Training Methodology

• Instructor‑led advanced demonstrations
• Hands‑on scanning with real components
• Case study analysis
• Scenario‑based flaw evaluation
• Daily quizzes & certification preparation

Organisational Impact

• Improved volumetric inspection accuracy
• Reduced welding failures & internal defects
• Enhanced compliance with global standards
• Stronger asset integrity & reliability
• Better documentation & reporting consistency

Personal Impact

• Higher technical confidence in TOFD
• Improved flaw detection & sizing skills
• Stronger understanding of diffraction physics
• Career advancement in advanced NDT roles
• Eligibility for ISO 9712 / ASNT certification

Who Should Attend?

• Experienced UT Level II inspectors
• Pipeline & welding inspectors
• Mechanical, civil & structural inspectors
• Advanced NDT technicians
• Anyone preparing for TOFD certification

Certificates

Upon successful completion, participants receive a GTMCS Certificate of Completion and are prepared for ISO 9712 / ASNT TOFD certification exams.