Case Studies

Spiral Wound Boiler Waterwalls

Effective UT coverage

Scanned 60 feet2
(5.6 meters2) per minute

UT readings

Collected nearly 15
million UT readings

Money savings

Saved nearly $5 million
on repair costs


  • Manual inspection of spiral wound boiler with multi-lead rifle tubing left large gaps in inspection coverage
  • Conventional UT cannot effectively differentiate the wall thickness between the ribs and gaps of internal rifling
  • A potential tube leak could cause forced outages and wall replacement costs totaling upwards of $5 million


  • Full-coverage Rapid Ultrasonic Gridding (RUG) inspection using TOKA® 4 robotic inspection platform
  • Gecko Portal® software


  • No scaffolding or dedicated company resources were required for the inspection
  • Nearly 15 million UT data readings obtained
  • Saved the plant several millions of dollars in replacement costs by pinpointing areas in need of repair
  • RUG’s specialized narrow beam immersion transducers reliably differentiated between rib and gap thickness in MLR tubing to provide accurate UT readings

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