SCOTT BADER SUPPLY MATERIALS OF CHOICE FOR SUBSEA STRUCTURES

Over 80 large covers for the protection of undersea oil and gas pipeline equipment have been recently manufactured, with a total GRP gross weight of 430 tonnes, and some covers weighing up to 10 tonnes each. The majority of the products have been supplied to Acergy Norway AS for the Tyrihans project.

The covers are designed to provide impact protection to pipeline connection points (manifolds/tees etc) from surface dropped objects such as drillpipes. Pipeline expansion zones, usually an area of Z-shaped pipework, are similarly protected, with the covers also providing overall protection to seabed installations against commercial trawling operations.

The GRP covers manufactured using the Scott Bader products are typically 24mm thick, sufficient to withstand a dropped-object impact force of 50kN. Areas of thicker laminate (up to 80mm) are also incorporated as lifting points for the heavier structures (maximum 30 tonnes).

GRP is the material of choice for these protective covers as it is very competitive compared to fabricated steel, and requires no anodic corrosion protection. Also installation weight is only 1/3 of a comparative steel structure, while still providing high impact strength.

The Scott Bader Crystic 703PA is a pre-accelerated, DCPD polyester resin with low viscosity and controlled exotherm characteristics. The material is approved by Lloyds Register of Shipping for marine applications and is suitable for vacuum injection and other similar production techniques, particularly with large structures. It is also compatible with most reinforcements and provides excellent mechanical properties and impact resistance.

On completion of the vacuum injection production process, the undersea mouldings are subject to an outer surface yellow gelcoat finish which ensures maximum visibility for seabed conditions. A final top gelcoat finish is also then applied. Both these products are also manufactured by Scott Bader, the coloured gelcoat being their Crystic 0209 SMK which is isophtalic with low styrene content and good self levelling properties. The final brushed topcoat is their economic Crystic X 103 KH which is a pre-accelerated orthophtalic gelcoat with a tack-free surface. Both these products are thixotropic polyester gelcoats, designed for rapid cure suitable for the production of high quality mouldings. Several other Scott Bader moulding accessories were also utilised, from their wide range suitable for a variety of production techniques from vacuum injection, ideal for prototype and other low output requirements, up to full resin transfer moulding (RTM) production of components utilising rigid composite or metal moulding tools.

Mr Jon Inge Brattekaas, General Manager of Sörkomp, explains: ‘We have been delighted with the service and co-operation provided by Scott Bader Scandinavia and their exclusive distributor in Norway, Hans Claussen AS of Oslo. Crystic products were chosen because they are well known here and have a long established brand name, coupled with extensive experience, proven quality, good product performance, reliable deliveries and realistic pricing. Their special Crystic 703PA DCPD infusion resin has given us big advantages for the fast production of very thick laminates up to 60mm, allowing us controlled geltime and low exotherm combined with very quick cure and productivity. Scott Bader’s products and technical service will also continue to play a major part in our future production plans.’