NDT.net June 2005, Vol. 10 No.06

FORCE Technology carried out Pressure Vessel Inspection

Amerada Hess: Excellent collaboration on South Arne produces results
The inspection was carried out within the planned deadline thanks to exemplary collaboration between the many parties involved on the rig, particularly including Amerada Hess's own staff and personnel from Rambøll.
Extensive task
The task consisted of carrying out PVI (Pressure Vessel Inspection) of approximately 12 vessels on South Arne during shutdown. The inspection consisted of precise visual inspection outside and in, so as to get an idea of the pressure vessel's current condition.

Prior to the vessel inspection a meeting was held with the customer (Amerada Hess) and DNV, at which the extent of the ispection, inspection methods and performance of the inspection were established. Special items which demanded extra attention during the inspection were also discussed.

FORCE Technology was to carry out NDT of new welds, thickness measurements at selected points and digital radiography, which meant there would be three inspectors from FORCE Technology on the rig.

Before we arrived, the facility was brought to a standstill and secured, so that the vessels could be opened and the necessary replacements of and modifications to the sections of pipe could begin.

The vessels were inspected prior to cleaning and the presence of any sand and sludge was noted. A British company was responsible for cleaning, and we established a good working relationship so they would call us each time a vessel was ready for inspection. They also kept us informed if any other "foreign bodies" were found during cleaning or if any other irregularities arose.
Many examinations going on at once
During the wait between the opening of the individual vessels, we took part in the ordinary NDT work, identification and localisation of sections of pipe which needed inspecting.

Amerada Hess had placed its lab at our disposal and here we were quickly able to set up shop with darkroom facilities, computers, calibration blocks, video- endoscopy equipment and other necessary gear.

We enjoyed efficient collaboration with construction supervisor Jens Ulrik Møller of Rambøll, and as the welding work proceeded, the isotope and magnet got to work. Digital photography was also in full swing. We had approximately 90 points that needed inspection.

Radiography endoscopy
Carrying out radiography on South Arne is difficult unless the installation is shut down. Production is governed to a high degree by radioactive level measurements and our isotope interfered with them. For this reason we were carry out much of the digital photography during shutdown.

As the vessels were inspected and approved, the results were passed on to Jens Guldhammer of Amerada Hess and Jens Ulrik Møller so the vessels could be closed again. Video-endoscopies were also carried out on three coolers, to which physical access was not possible.

Few problems
Since the rig is only five years old, there was a limit to the number of annotations identified. A corroded area at the bottom of a drain tank and a vessel with a defective inner coating were the most serious. NDT of new welds resulted in only a single repair.

In addition to the 12 vessels of which inspection had been planned, there was enough time left to inspect a further three. Progress made during the day and the ensuing results were reported to the rig supervisor every evening.

The role played by Rambøll
Arne Jager Andersen of Rambøll explains that his company is responsible for the design and practical implementation of so-called ”improvement packages” on South Arne. Although this involves completely new initiatives, it also includes repairs and preventive maintenance and subsequent replacement of components in the facility.

In connection with our inspections it was Rambøll that made sure we had access by providing scaffolding and by opening and cleaning the many pressure vessels we were to inspect internally in accordance with the rules laid down by the Energy Agency and the Working Environment Service.

The excellent working relationship between Rambøll and FORCE Technology's inspectors helped to get things running smoothly so that the inspections could be carried out efficiently and without time being wasted.

Rambøll were also pleased that our inspectors demonstrated considerable flexibility, e.g. by carrying out checks on new welds in between condition evaluations of piping and vessels.

FORCE Technology provided the necessary documentation for all its inspections on the rig, enabling Rambøll to collate, without undue delay, the necessary documentation for Amerada Hess, which was to use our report to obtain the Energy Agency's continued approval of the production permit on South Arne.

Amerada satisfied
Morten Nielsen of Amerada Hess was extremely satisfied with FORCE Technology's work. We carried out the NDT and vessel inspection necessary in connection with the shutdown, while at the same implementing the annual on-stream inspection programme.

Our inspectors demonstrated considerable flexibility and carried out their work to everyone's satisfaction. Performance of the on-stream programme during shutdown was particularly good because we avoided triggering fault notifications on their radioactive level meters with our radioactive isotope.

The fact that our inspectors were certified and approved for the performance of several different types of inspections, plus the flexibility they demonstrated, meant that the work could be carried out within the short period during which production was shut down.

Please contact us for further information.
FORCE Technology:
Park Allé 345, DK-2605 Brøndby
Phone: +45 43 26 70 00
Fax: +45 43 26 70 11
e-mail: force@force.dk
Internet: http://www.force.dk

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