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Protection from Winn & Coales
Protection from Winn & Coales
Keywords Winn & Coales, Pipelines, Protection, Sealing, Coatings
As part of its campaign to improve the quality of its water to the highest practical standards, Yorkshire Water is opening a new water treatment plant at Keldgate, Cottingham, near Hull. The contractors for the project are Clugston Construction Ltd.
Water is extracted from various East Yorkshire boreholes and is conveyed to the existing reservoirs, where it receives preliminary treatment, and will now be conveyed to the new Keldgate treatment plant.
Winn & Coales Denso products have been chosen for protection at Keldgate of joints and couplings on the large diameter ductile iron pipes, ranging from 400mm to 1 metre. This includes all flange connections, flange adapters and most couplings. The joints and flanges are first treated with Denso paste, followed by Denso Profiling Mastic to smooth the profile of the joints, and then Denso Tape is applied to complete the P1 water industry specification.
An interesting application here is on connections that are cast into concrete, where the Denso Tape can be wrapped right up to the concrete face.
A second Winn & Coales' contract is with Wirral Borough Council Engineers Department, which is responsible for the construction of the Wirral Tramway, a heritage tram system operating in Birkenhead. They have found that Winn & Coales' Densoband (formerly known as Tokband Spezial) makes an ideal flexible sealant between the tram rails and the asphalt surround. Used particularly on road crossings, it prevents gaps appearing between the rails and the adjacent road surface due to the vibration of the rails.
Densoband was specified by transport consultants, Merz McLellan, who designed the first phase of the tram system. Trackwork for the current phase, being laid by Hofa Rail, will complete a total installation to date of almost one mile. A further phase is proposed, which will be subject to a new Order under the Transport & Works Act, and will effectively double the length of the system. A long-term extension into Birkenhead town centre is also proposed.
The properties of Densoband are said to be such that, unlike bitumen sealants, it adheres to the metal rails as well as the road asphalt, and has a good lateral strength. As an effective flexible seal, it reportedly prevents the ingress of water from the surface running down through the joint, which in the marine environment of Merseyside can aggravate corrosion problems.
A third project involves Severn Trent Water Ltd, which is carrying out a renovation programme on seven pipebridges carrying treated water in Warwickshire. To give long-term protection and minimise costly future refurbishment the contractor, D & D Industrial Coatings Ltd of Warrington, Cheshire, is using Winn & Coales' Steelcoat 400 system on all pipelines and the adjacent steel structures forming the pipebridges.
Renovation of the pipebridges at Ragley Hall, Alcester, Lapworth and Chadwick End has already been completed (Plate 1). Work is now under way on the Berkswell pipebridge south of Coventry, which carries two 24-inch water pipelines over the main London to Birmingham railway line.
Plate 1 Winn & Coales' Steelcoat 400 system protects the Ragley Hall pipebridge
Although Steelcoat 400 system is being used on the pipebridge steelwork, the renovation work here differs from the other pipebridges in that D & D Industrial Coatings is using a jetty-pile jacket on the pipelines. Winn & Coales corrosion engineers, following an inspection of the pipelines, have designed the jacket. As the previous protective wrapping tape system was still in good condition, they designed a heavy-duty polyethylene jacket, which has been fixed over the pipelines using stainless steel banding.
Steelcoat 400 consists of Denso Hi-Tack Primer, followed by Denso Hi-Tack Tape to form the main corrosion prevention layer. This is then followed by Denso Ultraseal Tape, which is spirally applied to give a 25mm overlap. A final urethane topcoat can then be applied to complete the tough, weather resistant Steelcoat system.
British Airways' London Eye (Plate 2) is the latest example of the wide variety of anti-corrosion applications being found for Winn & Coales' Denso Void Filler.
Plate 2 The top of the box beam on the left leg of the London Eye's restraint tower can just be seen above the surface of the Thames. Both box beams are protected from corrosion by Denso Void Filler
The 135m diameter wheel of the London Eye weighs 1,500 tonnes, which can be up to 2,000 tonnes when each capsule is full. The engineering contractor, Tilbury Douglas Construction Ltd, point out that an important feature is the restraint towers, which control the speed of the wheel. The restraint towers can also lock the wheel in position in the event of high winds up to hurricane force – when it will obviously be closed to the public.
The leg of each restraint tower is fixed to a box beam of Macalloy bars, which is secured to the reinforced concrete plugs fixed to the top of the foundation piles. As a result of the London Eye's location on the South Bank of the Thames, the top of the Macalloy bars are covered with water at high tide. Protection from this corrosive environment is provided by the Denso Void Filler, which is a petrolatum compound containing additives to displace moisture and inhibit corrosion.
Details available from: Winn & Coales (Denso) Ltd, Tel +44 (0) 20 8670 7511; Fax: +44 (0) 20 8761 2456.