CUI Case Study

CUI Case Study

Case Study on Rope Access Techniques for CUI Inspection

National Petroleum & Refining Association

Document MC-02-87

THE USE OF ROPE ACCESS TECHNIQUES TO INSPECT FOR CORROSION UNDER INSULATION ON TOWERS IN AN OPERATING PROCESS PLANT

Site # 1 Work Scopes CUI visual and ultrasonic inspection of tower (8’ diameter x 175’ height) and its 18” overhead line.

  • Remove insulation around all insulation penetrations not accessible by platforms (approximately 60 nozzles and support clips).
  • Remove insulation 2 feet above and 1 foot below all stiffening rings (11 support rings).
  • Remove insulation at 9 locations on the 18-inch overhead line.
  • Visually inspect and take Ultrasonic Thickness readings, clean and prepare surface using hand tool methods, coat with primer and top coat, and re-insulate all uncovered areas.

Site #1 Cost Comparison

Site #1 Schedule Comparison

No safety incidents
Site # 1 – 65% cost savings using Rope Access methods as compared to conventional scaffolding based on fixed price quotes with 32 days for completion verses an estimated 75 days for scaffolding.
Site # 2 Work Scopes
CUI visual inspection of tower (10’ diameter. X 100’ height) and overhead line (12” diameter x 115’ length).
  • Remove insulation around all insulation penetrations not accessible by platforms (approximately 15 nozzles and support clips).
  • Remove 100% of insulation from the 12-inch overhead line.
  • Visually inspect and take Ultrasonic Thickness readings, clean and prepare surface using hand tool methods, coat with primer and top coat, and re-insulate all uncovered areas except for the overhead line.

Site #2 Cost Comparison

Site #2 Schedule Comparison

No safety incidents
    Site # 2 –. 45% cost savings using Rope Access methods as compared to conventional scaffolding based on fixed price quotes with 7 days for completion verses an estimated 21 days for scaffolding.