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Boiler Tube Weld Inspection

Inspection Challenges:

Boiler tube welds require a rapid volumetric inspection method. Traditionally, radiography (RT) is used, but this technology has several drawbacks. RT is insensitive to mis-oriented planar defects, it does not provide immediate feedback to the welders, and is disruptive to other activities. Mostly, safety regulations are getting more and more severe worldwide drastically restricting the use of radiography.

Encoded phased array UT technology can be a reliable and efficient alternative to RT for weld examination. However several challenges arise when attempting to perform inspections in the tight environment inside of a boiler: the major concern with boiler tubes is the low clearance between pipes; the other complexity is the small wall thickness of the pipes, combined with a variety of diameters, and the presence of the weld caps.

Recommended Solution & Advantages:

Phased Array UT in lieu of RT
pa-ut-in-lieu-of-rtZetec proposes a complete phased array UT inspection solution that addresses the challenges presented above: low-profile phased array UT probes and wedges, installed on the Circ-it scanner from Jireh Industries. With its 11 mm clearance and encoded circumferential movement, the Circ-it enables rapid and efficient inspections of small diameter pipe butt welds. The scanner can be adapted to different pipe diameters ranging from 0.5” to 4” NPS (21.4 to 114.3 mm OD).

To fully benefit from the low clearance of the Circ-it, Zetec offers an application specific set of probes and wedges. With frequencies ranging from 5 to 10 MHz and the option between 16 or 32 elements, the extra thin linear array probes allow for maximum detection capability. The arrays are curved to optimize focusing in thin tubes, and wedges are designed to reduce the distance to the weld center, allowing for better coverage of the examination volume.


Detects all defect types

  • Phased array UT can detect all defect types, and offers through-wall sizing capability

No disruption to other activities

  • As opposed to RT, the phased array UT inspection technology is not disruptive to other activities

Fast inspection time

  • The Zetec solution allows to inspect boiler tube welds from two sides in less than 1 minute, while adapting to tube diameters from 0.5” to 4” NPS

Efficient workflow

  • The on-board UltraVision Touch software ensures an efficient inspection workflow, from set up to analysis and reporting

Zetec Products:

topaz16_topaz32_webTOPAZ32 and TOPAZ16 systems

  • Fully-integrated portable phased array units
  • Battery operated, rugged, no air intake
  • Two-sided inspection in less than 1 minute
  • Accurate imaging: online S-Scan, Dynamic Merge
  • Methodology adaptable to applicable codes and requirements

Circ-it scanner from JIREH Industries

  • Low profile design: 11 mm radial clearance
  • Small diameters: From 21.4 to 114.3 mm (0.5” to 4.0” NPS)
  • Encoded scan: one-axis encoder along the circumference of the pipe
  • Modular and flexible design: quick change links for pipe diameter adjustments; single or dual probe scanning
  • Cable management system for irrigation lines and probe cables

Low-profile PA UT Probes & Wedges

  • Extra thin probe assembly: 11 mm clearance
  • Curved array for optimized focusing: r = 35 mm
  • Designed for sectorial scanning
  • Multiple frequencies available: 5 MHz for rough inspection surfaces (OD pitting); 7.5 MHz for standard inspections; 10 MHz for optimized detection and characterization of small volumetric indications (porosities, slag…)
  • 16 or 32 elements for optimized steering capability
  • Interchangeable wedges, optimized to minimize distance between probe and weld center line
  • Integrated irrigation and easy scanner interfacing
  • Wedge kit covers from 0.5” to 4” NPS and flat