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Sat March 06 2021

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A cold wind blows for designers

27 May 14 A rare old storm blew up in the usually calm area of offshore wind turbine design in 2009. Mark Clinton reports.

The Robin Rigg wind farm
The Robin Rigg wind farm

It became apparent that the international standard for the design of the foundations of these structures contained a rather important error. A variable used in one of the equations in the standard was underestimated by a factor of about ten.

The error had a serious implication for the loadbearing capacity of the grouted connection between the monopole foundation and the transition piece that sat over it. That resulted in unexpected and unwelcome movement in such structures and in particular, for present purposes, in the structures at the Robin Rigg offshore wind farm in the Solway Firth.

The cost of rectifying the problem at Robin Rigg ran to €26.25m. When it came to the argument as to who was to foot the bill, an interesting issue arose for the court to decide (MT HØjgaard  a/s v E.ON Climate & Renewables UK Robin Rigg East Ltd and another).

The contract was, as is so often the case, made up of a number of different documents.  They included an obligation to exercise an appropriate level of due care and diligence.  They also required compliance with the international standard. That much is no more than might be expected. However, there was also an obligation to ensure a design life of 20 years without planned replacement. Finally and for good measure, it was stated that the contractor was to assume full responsibility for design and construction.

Because of the error in the international standard, complying with it would not give a 20-year design life. The obligation to follow the standard was therefore incompatible with the obligation to ensure a 20-year design life. How was this conundrum to be resolved?

The court decided that the obligation to ensure a 20-year design life overrode the obligation to comply with the standard. The design life term was a fitness for purpose obligation.  The very expression strikes fear into the hearts of designers. This is because the test of compliance is whether the design or works meet the required standard. Unlike the case of an obligation to exercise reasonable skill and care, it is no defence that other designers would have done the same thing.

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In effect, the contractor had – probably unwittingly – warranted that the standard was compatible with a 20-year design life. He had taken the risk of the standard being wrong.

Another interesting observation of the judge in this case was that fitness for purpose obligations can sit alongside obligations to exercise reasonable skill and care. The common practice of inserting a skill and care obligation into a construction contract and assuming it will exclude the usual implied fitness for care obligation must now be open to question. The better approach is to state expressly that no warranty of fitness for purpose is given.

The case also shows us that when a fitness for purpose obligation bites, it can bite very hard.  The words ‘fitness for purpose’ may not be used but if you agree to ensure a particular result, you are entering into a fitness for purpose obligation.

About the author: Mark Clinton (below) is a partner at Thomas Eggar LLP.

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