AWARDS | BUILDING PEFORMANCE CHAMPION Judges praised the projects truly holistic approach to building performance and wellbeing We removed the eco-bling to focus on good engineering David Palin maximise the impact of these systems, and toidentify anomalies and opportunities. To assist the tuning process and build knowledge of indoor environment quality, several Samba monitoring systems were embedded within the Mirvac tenancy. The units offer a rich insight into indoor environmental quality (IEQ) parameters and help optimise plant operating periods. In addition to the Samba IEQ data, Mirvac did post-occupancy evaluation surveys using the Building Occupants Survey System Australia (Bossa), developed at the University of Sydneys IEQ lab, headed by Professor Richard de Dear. A survey was conducted on employees in Mirvacs ageing offices before their relocation. After a six-month honeymoon period in their new200GeorgeStreet accommodation, a second survey wasundertaken. Mirvac found a significant improvement in employee perception of IEQ. Scores for overall performance, health and productivity improved by 35%; noise distraction and privacy scores improved 50%; and spatial comfort scores also increased by 50%. In fact, the EY Centre outscored Mirvacs former head office across all categories. The 5.5-star Nabers for Offices energy rating is a significant achievement in a premium-grade office tower without tri-generation or renewables, and an improvement on Mirvacs 5-star target. How did we get the scheme from 5 to 5.5? The quality of the faade makes a big difference in managing heat loads, says Palin. The improved rating represents a 26% reduction in carbon emissions over a 5-star performance, representing a reduction of approximately 733tCO2e. With 200 George, we save about A$200,000 in energy ayear by having a 5.5-star rather than a 5-star Nabers energy rating. That reduction in building operational costs represents a significant potential valuation increase of AUS$3.78m (using a 5% cap rate) for thebuilding owners, says Palin. The buildings energy-use intensity is84kWh.m-2. The scheme has subsequently achieved 5.5 star Nabers for Offices Indoor Environment rating and the six floors that Mirvac occupies for its new HQ have the kudos of being the first in Australia to be certified under the Well Building Standard, for which they achieved a gold rating. The building has also achieved the 6 star Green Star Design, As-built and Performance ratings that Mirvac was targeting. We didnt target Well for the whole building because Well came to our attention after the project was under way. But we wanted to learn about it, so we targeted Well for our tenancy space, says Palin. Not every target has been met, however. The development target of a 4-star Nabers water rating was missed during the first year of operation, with the building managing 3.5 stars. A reduction of 38L.m-2 would have been required to achieve this result. The operational team is working on reducing water consumption and optimising rainwater capture and reuse to deliver on design objectives. Were only 3.5stars on the water, but well get there; it shows that you can be water efficient, energy efficient and have a beautiful building, Palin says. With credentials such as these, it will come as no surprise to hear that the building won the Project of the Year International category, and walked away with the best-of-the-best award, at this years CIBSE Building Performance Awards. The judges described it as an exemplary project and praised the truly holistic approach to building performance and wellbeing. CJ 36 March 2019 www.cibsejournal.com CIBSE Mar19 pp32-34, 36 Mirvac v2.indd 36 25/02/2019 09:29