The innovative use of a double-skin Clima façade based on a specification provided by Saint-Gobain Glass has created one of the major energy-efficiency features for One Angel Square, said to be one of the most sustainable large buildings in Europe.
Wide air gaps between a laminated glass outer skin and the main double-glazing of the newly completed Co-operative Group headquarters in Central Manchester enables the entire surface of the £105 million construction to breathe, providing constant ventilation and heat dispersion at the same time as maximising the building’s solar gain.
Saint-Gobain Glass provided more than 10,000sq metres of glazing for the unique building’s envelope. The outer skin is made up of 17.5mm Stadip Securit, constructed of two 8mm sheets of heat-treated Planilux float glass laminated together using a 1.52mm clear PVB for safety and security. The inner skin is SGG’s low-E commercial offering, Planitherm Ultra N, with a U-value of 1.1W/m2K, which provides the thermal insulating properties required for such an energy-efficient building.
Planitherm Ultra N now has a seven year track record with many major successes along the way, but SGG Senior Technical Sales Manager Richard Hickson says One Angel Square stands as “the pinnacle of achievement” for the glass.
He explained, “Performance was critical in such a construction and Planitherm Ultra N has proved itself over and over again in commercial projects of all sizes over the years. Unlike Window Energy Rating (WER) products which depend on a high g-value, it has a lower g-value which helps to reduce overheating. This, combined with its neutrality, processability and durability makes it the product of choice in such a context.”
A further demand came from the building’s unusual shape, he added; “The panes of the outer skin were parallelogram rather than rectangular, a similar challenge to the triangular panes of the Gherkin in London - another SGG project which used Planitherm Ultra N. We’re proud to say that all the panes were fitted perfectly!”
The striking building forms the nucleus of the massive NOMA 53 project - a 20-acre development set to transform the city centre over the next 10 years - with 4 million sq ft of office, retail and residential space, all powered by its own green energy centre.
The building uses a raft of green technologies to give One Angel Square an Energy-Plus status, meaning that it produces more energy than it imports. Some of the technology used to achieve this include power generation from biodiesel cogeneration using rapeseed oil, adiabatic cooling, rainwater harvesting, grey water recycling and waste heat recycling. The Clima double-skin glazing incorporating Planitherm Ultra N is amongst these leading-edge environmental functions that have earned this building a BREEAM ‘Outstanding’ rating.