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FAST UT testing is a proprietary method owned by SGS. It is an innovative use of a 70° longitudinal wave to improve both detection reliability and sizing accuracy of planar flaws.


Thin material presents a problem for traditional shearwave ultrasonic testing methods because of the short distances and acoustic properties of ultrasonic transducers and thin materials. Our innovative technique makes use of a high angle L-wave and mode converted beams to achieve reliable inspections in thin materials.

Although mainly used for inspecting pipeline welds, FAST UT was developed and approved for use by the Electronic Power Research Institute to improve the reliability of ultrasonic inspection of welds in thin walled components in the nuclear power industry.

Our FAST UT service delivers:

  • Reliable, repeatable results in thin materials
  • Improved confidence in inspections
  • Reduced equipment requirements
  • Fewer calibrations
  • Savings on examination time
  • Reduced false calls

The most outstanding feature of FAST UT is that it does not produce confusing geometric reflections from features such as root beads, counter bores and backing rings. As a result, deep flaws cannot be interpreted as geometry.

Over time, FAST UT has been developed and refined to enable the reliable inspection of a variety of components, materials and thicknesses.

FAST has been very successfully used for:

  • Thin wall weld inspection
  • Thin wall crack detection and sizing
  • Pipeline long seam and girth weld inspection
  • Pipeline crack detection and sizing
  • SCC sizing
  • IGSCC detection and sizing
  • Thru wall sizing of planar flaws
  • Boiler tube welds
  • Heat exchanger tube welds
  • Single Side Access S/S Examinations

New applications are developed frequently to assist in the inspection of new welds. FAST UT has made inspection of thin-walled components feasible and reliable. Welds in boiler tubes, pharmaceutical piping and heat exchanger tubing are being inspected with excellent reliability.

Why use SGS?

With FAST, the entire volume of weld can be inspected in a single scan with a single transducer, much like a phased array or a multiple transducer system. This attribute allows for inexpensive and reliable inspection of pipeline welds. This attribute makes FAST more reliable than Phased Array UT for accurately characterizing cracks in thin walled piping systems.

When FAST UT is automated the entire weld volume is examined in one line scan and flaw size information is obtained at the same time as detection.

Contact SGS today to find out more about how FAST UT testing can support your organization.