Eden Project, Cornwall

Few people in the UK have not heard of the Eden Project, a series of giant conservatories in Cornwall housing a living world of plants from around the world. The conservatories, or Biomes, are 3D space frames of lightweight galvanized steel tubes designed to form self-supporting shells.

What is not widely known is the part played by a team from SPC in saving the structures from a potentially very costly situation and helping to keep the opening day on schedule.

Quality control on the galvanizing was critical once each structure – 240 metres long, 55 metres at the highest point and 110 metres maximum width – had been erected to ensure longevity and the highest levels of corrosion resistance. The steel frames are triple glazed with ethyl tetra fluoro ethylene (ETFE) foil which would be prohibitively expensive to replace.

Yet before the official opening took place in March 2001, inspectors claimed that the zinc thickness on the supporting frames for the Biomes was 10 per cent below specification. As a result, the architects suggested that an additional 50 µm of zinc-rich paint should be applied to ensure the specified 25 years of maintenance-free life.

The problem was two-fold: the considerable cost and the time factor, which meant that the opening would not have taken place as planned – and this was in addition to the technical difficulties in implementing this recommendation.

Specialists from SPC examined the structures and measured the zinc thickness, before concluding that the existing system would protect the structure from corrosion for 25 years in that environment – well within the specification.

It was one of many occasions when SPC can claim to have literally saved the day!

Lloyds Building, London

Like a team of detectives looking for clues and finding the culprits, SPC are the experts when it comes to assessing coatings failures on steel framed buildings across the UK.

With SPC, however, the investigations focus not only on the human perpetrators but also the materials and systems which have caused the problem.

General deterioration and intumescent coating failures of corrosion protection systems on a wide range of buildings have been investigated by SPC personnel, with ‘culprits’ discovered and remedial recommendations taken up.

A good example of this is the Lloyds Building in London, famous for its “inside out” piping and building services. Serious leakage of service pipes on the external walls was being experienced only five years after it had been built, but the reason behind it was a mystery.

Members of the SPC team were retained by WS Atkins plc to conduct a thorough investigation. They concluded that the problem was a far from typical one.

The failure, it was discovered, was mainly due to the use of very strong cleaning chemicals used by a building services sub-contractor, which affected the joints, the insulation and the primary protective coating.

Coatings failures on other buildings investigated by the SPC team include the World Cargo building, Heathrow; the MAFF building in York, the SAGA Insurance building in Folkestone and the Courthouse and Registry buildings in the Isle of Man.