testex

Hole in storage tank discovered through thick scale with Falcon 2000 Floor Scanner

TesTex NDT Ltd. were tasked to conduct an Out of Service NDT inspection of an above ground, flat bottomed storage tank, the internal floor plate surfaces had not been shot blasted / prepared to SA-2 standard and were covered with a medium to heavy scale. The TesTex Falcon 2000. Low Frequency Electromagnetic Technique (LFET) Floor Scanner was used in an attempt to scan the floor plates through the scale.

The floor scans were showing the plates to be generally in good condition with no indication of reportable wall losses, however the scanner did show one isolated indication of severe wall loss and the NDT technicians investigated the area, scraping away the scale and debris to reveal a damaged area of plate and eventually poked through to a hole. Further investigations revealed that the damaged area had resulted from the years of dipping the tank without having a sacrificial striker plate installed below the dip hatch. The dip hatch had not been used for a while, thus allowing the area to be scaled over and hidden from a visual inspection.

In summary, this demonstrates the capabilities of the TesTex developed Falcon 2000 floor scanner, also the importance of good surface preparation and keen eyed NDT technicians.

 

The images above show the screen shots from the floor scan highlighting the damaged area, notice the good condition of the surrounding plate.

The images above show the hole and the investigation where a Plumb Bob was lowered through the roofs dip hatch.