Atmospheric tank inspection

Challenge

Inspectahire was contracted by Occidental Petroleum Qatar to carry out in-service tank inspection to comply with current EEMUA 159 Guidelines on their final settling tanks on Halul Island in Qatar.


Solution

An in-service inspection was carried out on the above tank incorporating all of the tank features including drainage, foundations, shell, roof, wind girder, tank floor, welds, nozzles and manways, flow lines, fire sprinkler system and all structures. A team of rope access technicians with the appropriate NDT discipline qualifications were utilised to gather information and inspect areas where access was difficult. Meanwhile, a further team operated an Ultrasonic Crawler remotely from the ground gathering data on the tank shell and roof. All works were overseen by a qualified tank assessor, who collated the information and carried out the required calculations so as to inform on the tank condition for further operations.

The two main types of atmospheric storage tanks encountered are Floating Roof Tank and Fixed Roof Tank. Each type of tank requires a range of inspection techniques, for example:

Tank Inspection Techniques

  • MPI -Magnetic Particle Inspection- Used for the inspection of the Shell to Bottom Weld and seam welds
  • Dye Penetrate-Used for the inspection of the Shell to Bottom Weld and seam welds
  • Magnetic Flux Leakage-Used to assess the condition of the tank floor and locate defects on underside of floor plates
  • Pulsed Eddy Current-Used to assess the condition of the annular ring
  • Vacuum Box-Used to test the integrity of the Shell / Bottom weld and majority of Seam Welds
  • CCTV and Pneumatic Mast-Used for the inspection of Drains, Pipes, and areas where access is most difficult negating the use of scaffolding where access is at height.
  • Ultrasonic and Remote Ultrasonic-Remote Ultrasonic to measure the wall thickness of the Shell strakes and Tank roof plates by following vertical Scan Lines on the tank shell from the ground.
  • Visual-Overall inspection of foundations, holding bolts

Result

A qualified tank inspection report was produced for both tanks and this completed Occidentals compliance requirement under the EEMUA 159 standards for inspection of storage tanks.