Steelcoat protects around Ben Nevis

Citation

(2002), "Steelcoat protects around Ben Nevis", Anti-Corrosion Methods and Materials, Vol. 49 No. 1. https://doi.org/10.1108/acmm.2002.12849aab.005

Steelcoat protects around Ben Nevis

Keywords: Coatings, Corrosion prevention

Alcan Smelting and Power UK maintain two hydro electric power stations near Fort William to provide power for the alummium smelter at the foot of Ban Nevis. Water is fed into the power station through over ten miles of steel penstock pipes up to two meters diameter. Maintenance of these pipelines is difficult in such harsh conditions. and one problem area over the years has been entrapment of moss and water in the voids of the sliding pipe supports creating a local corrosion environment.Having used Winn & Coales Denso protection systems for a number of years Alcan's maintenance engineers have now switched to Winn & Coales latest Steelcoat 100 system for its rolling maintenance programme of the void areas on the 10 miles of process water pipes. The specialist contractors for its application are Paknon Ltd of Grangemouth Road, Bowness.

The Denso Steelcoat system were designed for the long-term protection of above ground steel structures and pipework. They are a combination of heavy duty surface-tolerant liquid coatings and tape wraps, all of which carry extensive track records in highly corrosive environments. They are said to be easy to apply, suitable for application in many difficult or confined areas and thought ideal for steel surfaces which cannot be abrasive blast cleaned.

In a second project maintenance engineers at the BP Coryton, Essex, refinery have refurbished a massive tank used for holding raffinate. Measuring 95ft in diameter by 44ft at the highest point, the tank holds 39,000 US barrels of product, which amounts to in excess of it million gallons (Plate 4).

Plate 4 Winn & Coates' Steelcoat protects the void areas of the pipe supports on the ten miles of Alcan water pipes around Ben Nevis

The raffinate tank is rivetted and national contractors Deborah Services Ltd applied a stripe coat of Winn Coales Archco-Rigidon 403D as a caulking to seal and protect the rivet heads and joints of the tank walls. Archco-Rigidon 403D lining was also applied to the entire floor area of the tank and, as with the walls, was thickness checked after application and spark tested to ensure a pinhole-free surface.

Archco-Rigidon 403D was specified for this project following its successful use on several smaller tanks and refinery vessels at Coryton over the past twelve months.

The Winn & Coales specialist lining is described as a vinyl ester based flake glass filled coating offering excellent long term corrosion/erosion resistance in highly corrosive environments (Plate 5).

Plate 5 Archo-Rigidon 403D protectsx the rivet heads and joints of this raffinate tank at BP Coryton and the entire floor area

Contractors Balfour Beatty Construction have recently completed a contract involving the strengthening of the M8 Kingston Bridge, Glasgow, for the Scottish Executive and Glasgow City Council.

Once again a key feature of the contract was the anti-corrosion protection provided by Winn Coales Steelcoat 50 system, based on Denso Void Filler.

There are approximately 3,000 bolt heads on the bridge, which are located on the end of prestressing tendons introduced to strengthen the structure. Balfour Beatty Construction are ensured that each bolt head has been protected with a termination cap filled with the Denso Void Filler to provide long-life anti- corrosion protection. Specialist contractor Balvac, also a Balfour Beatty company, applied the Denso Void Filler to the stressing tendons also as part of the contract.

Denso Void Filler is a petrolatum compound, which contains additives to displace moisture and inhibit corrosion. It can be injected hot from a heated tank with its own pumping system specifically designed by Winn & Coales Engineering Division (Plate 6).

Plate 6 Denso Void Filler protects some 3000 bolt heads on Glasgow's M8 Kingston Bridge

Denso Void Filler has been used on a number of major international construction projects, including the protection of all the stay cables and internal/external post tensioning steel strands on the Second Severn Crossing. It has also recently been used to protect rock anchors at Devonport Royal Dockyard.

Amec Capital Projects are working on a major extension to Tilbury Container Services Riverside deep water berth which will enable it to accommodate the world's largest container ships. The project involves the use of 218 40m x 100 mm tie bars and tie bar eye couplers (pin joints), plus three turnbuckles on each tie bar. Winn & Coales specialist wrapping tape system are also being used this project. Amec are using the system to ensure long term protection against the testing environment of the Thames estuary, both below water and in the tidal zone.

The tie bars are supplied by Normanby Industries of Scunthorpe factory wrapped with Winn & Coales Denso Tape followed by Denso black PVC self-adhesive Tape. At Tilbury Amec apply the Denso protection system to the eye couplers and the turnbuckles. In the case of the eye couplers (where work has to be carried out at low tide) Denso Primer is applied followed by Densyl Mastic to smooth the contours, then Denso Tape and finally encapsulated in a yellow Denso PVC self-adhesive Tape. The turnbuckles receive the same protection but do not require the Densyl Mastic (Plate 7).

Plate 7 Protecting tie bars at the Tilbury deep water berth extension with Denso Tape

In yet another project involving Winn Coales, contractors Harbour General Works Ltd of Gateshead are currently carrying out a refurbishment project for North West Water's Walton-le-Vale sewage treatment works near Preston.

The project includes the strengthening of eight concrete treatment tanks, each of some 100m circumference. These have been encircled with post-tensioning steel cables and tightened through steel stressing bars. For long term protection the steel blocks have been coated with Winn & Coales new Denso Epoxy CTR, with Denso Tape followed by Denso self-adhesive PVC Tape being applied to the stressing bars. This work was carried out by sub-contractors YSL Systems (UK) Ltd of St. Neots, Cambs (Plate 8).

Plate 8 Steel blocks at Preston sewage works coated with Denso Epoxy CTR and Denso Tape and PVC tape on the stressing bars

Winn & Coales recently introduced Denso Epoxy CTR is a new non-carcinogenic alternative to coal tar epoxy coatings which is reported to be VOC compliant (89 per cent solids).

Denso Tape is a non-woven synthetic fibre fabric impregnated and coated with and adhesive compound based on petrolatum.

Details available from: Winn Coales (Denso) Ltd. Tel: +44 (0) 20 8670 7511; Fax: +44 (0) 20 8761 2456.