Guided Wave Long Range Ultrasonic Testing [GW LRUT]

Long Range Ultrasonic testing (LRUT) also known as Guided Wave Ultrasonic testing (GWUT) is an Ultrasonic method wherein ultrasonic waves are transmitted along the pipe wall (guiding walls) up to 150meters in length. Long Range Ultrasonic testing is a rapid screening test method for integrity assessment of pipelines, non-piggable buried, encased piping, vertical or inaccessible piping (e.g. overhead pipe racks) or epoxy coated pipelines to locate areas of potential degradation or engineering concerns and gross discontinuities for targeted assessment and inspection. While conventional NDT test methods provide localized inspection, underneath or in the vicinity of the sensors, LRUT is able to test 100% circumferential wall over tens of meters of the pipe length from the single inspection (contact point) location

Our solution 

AlphaNDT’s offers LRUT to apply on pipelines having limited access or only localized access; to avoid unnecessary excavation, coating removal or scaffolding installation. The use of LRUT significantly reduces maintenance costs and is a perfect inspection method for unpiggable pipes or inaccessible pipe sections. LRUT can be used on pipe diameters ranging from 38mm (1.5”) to 1200mm (48”) to detect loss of cross section (LSC) or areas of concern such as corrosion or erosion pockets around the pipe's circumference. LRUT technology works effectively while your piping system is in operation (up to 80°C / 176°F) including on insulated or buried sections. Typical test ranges of ±30m (96ft.) can be achieved from a single location, with up to 150m (450ft.) under ideal conditions.


  • Rapid inspection of in-service pipelines and piping for detecting corrosion or areas of concern (LCS)
  • Buried pipelines at the excavation locations or at level crossings
  • Encased (through-wall) pipelines or culvert line or PE coated pipes
  • Vertical pipes or structural circular columns
  • Inaccessible piping e.g. overhead piping rack
  • Requirement for high speed assessment to reduce cost reduction - Eliminate the cost of complete scaffolding or use of Elevated working platforms due to which testing speed is reduced.
  • Insulated pipelines and piping – No need to remove entire pipeline insulation
  • Detection of corrosion at pipe supports, clamps and pipe racks
  • Refinery, chemical plants, power station piping
  • Risers and offshore topside pipe work
  • Jetty lines and river crossing pipelines, tank farm link lines and sewer lines


  • In-service inspection prevents production losses or downtime.
  • High productivity inspection - Reduction in onsite inspection time – maximum examination speed is 180meters per hour.
  • Examine 180meters (90m from each side of the transducers) from the single test location
  • Examine 100% of the pipe circumferential wall from the single test location (contact point)
  • Maintenance cost reduction by not removing surface coating of the entire pipeline except 500mm width exposed to attach transducers.
  • No need to sand blast or grind entire pipeline surface under examination
  • No need to excavate the entire non-piggable pipeline or random spot tests
  • No need for a couplant which is necessary in conventional ultrasonics.
  • Detects weld root erosion faster than conventional test methods
  • AlphaNDT’s exclusive, one-stop service