DESIGN FOR PERFORMANCE | PIONEER PROJECTS PERFORMANCE PIONEERS Eleven office developments will trial the UK version of Australias Nabers rating scheme, which grades buildings by actual performance. Andy Pearson speaks to consultants on the Design for Performance initiative about outcome-based designs I t is a sobering fact that a typical new office base building in London could be using up to six times more energy on a like-for-like basis than the best new prime office building equivalents in Melbourne, Australia, the antipodean city with a similar, though slightly warmer, climate. Even the best new offices in London could be using three times more energy than their Melbourne equivalent. One of the reasons for this striking differential is that the focus in the UK is on design and predicted energy performance of the base building (and in the worst-case scenarios, only compliance) whereas, in Australia, the focus in on the measured actual energy performance of the base building. By contrast, in Australia in addition to achieving compliance it is mandated that the operational energy efficiency of large commercial office buildings is measured and rated using the Nabers scheme. (Of course, not all buildings in the UK ignore operational performance as the widespread use of TM54: Evaluating Operational Energy Performance of Buildings at the Design Stage testifies. ) The Better Buildings Partnerships (BBPs) Design for Performance (DfP) initiative is an industry-backed project instigated to tackle the performance gap in the UK. Based on the established Nabers methodology, it sets out to deliver measurable performance outcomes to ensure UK office developments deliver on their design intent. To date, the BBP has undertaken a feasibility study followed by a series of pilot projects. More recently, it announced that 11 pioneering office developments will be trialling a DfP approach to office design. Consultant Arup is working on two of these pioneer projects: Derwent Londons 9-35 Baker Street development and Stanhopes 2 Ruskin Square, Croydon. There is an expectation from both clients that the ratings we achieve for these buildings will be important by the time schemes hit the market, says Stephen Hill, a sustainability consultant and associate at Arup. He believes that the DfP approach fits into the sustainability strategy Arup now uses on the majority of its projects. This involves using advanced energy modelling to establish operational performance targets. DfP is helping us engage with our clients to have more meaningful conversations about what those [operational] targets should be and what project teams should be doing to make sure those targets are achieved, Hill says. Arup is in the fortunate position of being able to draw on the experience of engineers working in its Australian offices with experience of delivering Nabers. We are providing a lot of input to our clients based on our Australian experience of things such as contractor relationships, how contractors can contribute to the DfP process, and how contractual relationships with tenants can work, Hill explains. He adds that advanced energy modelling will need to be part of the design process for MEP design firms if they are to deliver DfP projects. The model needs to be sufficiently mature at RIBA Stage 2 to inform the broad decisions around massing and faades, and then it needs to evolve through Stages 3 and 4 to the point where you have a pretty detailed model capable of capturing the efficiency of individual pieces of equipment in the building, Hill says. 40 October 2020 www.cibsejournal.com CIBSE Oct20 pp40-42 DFP Overview.indd 40 25/09/2020 18:38