The North Sea's Britannia platform has benefited from an innovative new technology from Vector International, helping it to meet tight deadlines for a nine-day maintenance shutdown last month (July), by providing a means of testing the integrity of clamp connectors prior to a complete system pressure test.

Reverse Integrity Testing (RIT) rings are a new means of testing and verifying individual joint integrity, in-situ, as the joints are installed and were used to test Techlok clamp connectors as part of the planned maintenance work on Britannia and the first time the technology had been used on the platform.

Testing joints during installation is a significant advantage as it enables any non-conformances to be identified before a final pressure test and corrected immediately. To lose one day's production due to an overrun with the shutdown would have lost about 700 million standard cubic feet of gas and 35,000 barrels of condensate (equivalent to about 8% of the UK gas supply).

"Typically, once the planned work on a connector has been completed it would be necessary to wait for all other planned procedures on the same line to be finished before a full pressure test could be conducted. To find a connector has not been installed correctly and is therefore not sealing properly, for example, at this stage could delay completion of the shutdown until it is rectified, incurring significant additional costs. Using RIT rings we were able to test the connectors without delay so any potential problems could be detected ahead of the full pressure test," explains Syd Lyth, Vector project product support engineer. "In this instance no faults were identified, but there would have be no way of knowing this in advance of full line test without RIT rings."

Mike Matthews, Britannia shutdown co-ordinator commented: "We've been attracted by the potential time savings to be made using RIT rings. This shutdown was the ideal opportunity to use the RIT rings were 100 per cent successful on the connectors on which they we used. We already plan to use the technology again and as confidence grows with further use, we're hopeful that RIT rings will replace a full leak test following any maintenance work, bringing widespread time savings."

The principle of the RIT rings is to reverse-test (or test the 'wrong way') the lips of the sealring, putting a very onerous test on the seal. The RIT ring and within the hub and is used to put external pressure on the self-energising Techlok seal, in effect seeking to de-energise the seal-ring lips. The medium can be either hydraulic oil or gas, and the presence of any leak is identified by a significant pressure loss.

As part of the 'healthcare' agreement Vector holds with Britannia its engineers worked closely with Britannia personnel to achieve a successful shutdown and reinstatement, including attending all shutdown meetings. Vector was responsible for identifying all the materials required to carry out vessel isolations such as bolts, gaskets, sealrings, blind flanges and lifting aids, to name but a few, and reinstate them afterwards. Vector's continuing long-term partnership with Britannia which stretches nearly 10 years, and its in-depth knowledge of the all the major vessels sees it providing a service that is synonymous with its position as a solutions provider for all pressure containment needs.

Following shutdown Vector is inspecting all removed and unused components, which will be catalogued and stored on behalf of Britannia until required for further projects.