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Time of Flight Diffraction

The gold standard for weld inspection sizing and monitoring

TOFD Inspection

Unmatched Accuracy in Defect Sizing

Time of Flight Diffraction (TOFD) is internationally recognised as one of the most reliable and accurate methods for detecting and sizing weld defects. By measuring the time it takes for diffracted ultrasonic waves to travel between two probes, TOFD provides precise depth and length measurements of flaws — independent of their orientation, type, or surface roughness.

Our TOFD services are performed in accordance with ASME V Article 4, BS EN ISO 10863, and API RP 2X standards. We deploy TOFD as both a standalone inspection technique and in combination with PAUT for comprehensive weld coverage — particularly on thick-walled pressure equipment and critical pipeline girth welds.

TOFD excels where conventional UT and radiography fall short. It offers rapid scanning speeds, immediate results, and the ability to detect both surface-breaking and embedded defects with sizing accuracy typically within ±1mm. This makes it indispensable for fabrication QC, in-service monitoring, and fitness-for-service assessments.

  • ASME V, BS EN ISO 10863 & API RP 2X compliant
  • Sizing accuracy typically within ±1mm
  • Detects flaws regardless of orientation or type
  • Immediate results with full digital traceability
Industrial welding process for TOFD inspection
Applications

Key Applications

Pre-Service Weld Inspection

Comprehensive inspection of new fabrication welds during construction and turnarounds. TOFD provides the highest confidence in weld quality before equipment enters service, meeting the most stringent code requirements.

In-Service Monitoring

Periodic TOFD scans allow precise tracking of known indications over time. By comparing successive scans, we can determine whether a defect is growing and advise on safe operating intervals or repair timing.

Fitness-for-Service (FFS)

TOFD provides the accurate flaw sizing data required for Engineering Critical Assessments (ECA) per API 579 / BS 7910. This data-driven approach can extend equipment life and avoid unnecessary shutdowns.

Why TOFD

The TOFD Advantage

TOFD is the technique of choice for critical welds on pressure vessels, heat exchangers, and pipeline tie-ins where precise defect data drives engineering decisions worth millions.

Highest Probability of Detection for planar defects (cracks, lack of fusion)

No orientation dependency — detects flaws conventional UT may miss

No radiation hazards — safer than radiographic testing

Full volume coverage of the weld in a single scan pass

Permanent, encoded data for audit and regulatory compliance

Need TOFD Inspection?

Get precise defect sizing data for your critical welds. Our team is ready to deploy.

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