Design life: duty or desire?

Any construction project (or product) can be stated to have a specific design life – normally listed in calendar years.

Recent cases have reviewed if a design life is a promise ie an actionably duty or a mere statement of intent or desire:

  • sinking wind turbines: a requirement for these to be designed to ensure a design life of 20 years (tucked away in the technical requirements) was upheld when defects were found within months of completion; and the contractor had to pay the €26m costs of rectifying the sinking sensation!
  • spontaneously cracking glass panes: a prestigious mixed-use redevelopment in the City of London suffered bad publicity and required £14m of re-works, including £9m for replacing the outer glass curtain walling. The contract had stated a design life of 30 years.
  • a roofless seafront tram station:  the new tram station, including its roof, was meant to have a design life of at least 20 years. 4 years after completion the roof blew off and various components were found to be unexpectedly rusty, leaving the Council with a bill for over £1m.

Unlimited Guarantee?

From these cases, the courts have confirmed that ‘design life’ means that the design of the relevant parts of the works would be suitable for that lifetime, but not act as a guarantee that those parts would last for that period without replacement. The contractor is also allowed to assume that the owner will carry out routine maintenance to extend the life of the works.

The court reminded the parties that “given the forces of nature, a lifetime of any specified period could never in practice be guaranteed” which was especially relevant as two of these projects faced westerly winds, sea salt and storms.

Whilst not a guarantee of a specific lifespan, the terms are duties. They create strict liability because the terms are absolute, objective and measurable. It doesn’t matter how much skill and care has gone into the choice of components, the overall design of the project or the workmanship… if the products don’t last then the contractor has failed in its duties.

What should you do?

As a (sub)contractor, beware any terms in any of the contract documents which state that a product will have a specific design life. Instead of deleting each and every one, your contract could state that “nothing in the contract will create a strict liability or fitness for purpose obligation on the (sub)contractor.”

As a client, instead of relying on these rather broad brush catch-all provisions, consider the functionality and performance of the project and its components. Be as specific as you can, and inspect/test to check this has been achieved at completion. Like Blackpool you can be really clear how much maintenance you expect to carry out and how much you expect their choice of product to match your needs.

Related content: promising the impossible, no guarantee, fit for what purpose.

Cases: MT Hojgaard AS v E.ON Climate and Renewables UK Robin Rigg East Ltd & Anor [2017] UKSC 59; 125 OBS (Nominees1) & Anor v Lend Lease Construction (Europe) Ltd & Anor [2017] EWHC 25; Blackpool Borough Council v Volkerfitz Patrick Ltd & Ors [2020] EWHC 1523

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