GREEN OFFICE POLITICS
GREEN OFFICE POLITICS
Double bay is home to an innovative commercial building.
People used to say Double Bay was vogue on the outside and vague inside, environmental consultant Michael Mobbs says. “Now homes are vogue on the outside and green inside.”
Not that building K wears its green credentials on its façade. On a prime corner site at 376 New South Head Road, the four-storey commercial block presents a conventional, if elegant, face to the outside world. Yet tenants don’t need to switch on lights during the day. They can open their windows to cool down. They drink rainwater and all sewage is recycled onsite. All together, these measures are estimated to cut its greenhouse gas emissions by about 150 tonnes a year.
At the heart of the building’s green credentials is its miserly use of water. All drinking water comes from an 80,000 liter tank below the ground floor that is filled by rainwater from the roof. A first flush diverter stops dirt from the roof finding its way into the drinking supply. The water then passes through ultra-violet purifiers to provide an extra margin of safety. It’s estimated the building will capture 400,000 litres of water annually.
Sewage or “black water”, from toilets and hand basins is recycled in an underground tank and is ultimately used to flush toilets around the building. Because about two-thirds of the water consumed by a commercial building is used for flushing toilets, this process makes big inroads into the building’s overall water consumption.
Such systems allow the building to operate independently of the mains water supply. Calculations show the building and its 200 tenants should be able to operate solely on rainwater and recycled water but if it runs short, the tanks can be topped up by a water tanker.
Architect Bruce Eeles says he was delighted to be able to take such an innovative approach in Double Bay. “Here was an opportunity to see how far things could be pushed in a commercial building,” he says. “I certainly don’t know of any other speculative office development that has water recycling.”
As well as conserving water, the building is designed to minimise its energy consumption. Glass walls and “light shelves” combine to channel natural light deep into the interior of each floor, reducing the number of hours artificial lighting is required.
Mobbs says minimum lighting requirements should be met most days of the year without switching on a light. The building has air-conditioning but it shouldn’t be required much of the time because of the passive ventilation provided by adjustable external louvers and a thermal “chimney” that runs through the centre of the building. The windows open, a radical departure for most commercial properties.
The projected savings in electricity and water depend how the tenants choose to use the building, which is why there are water and electricity meters for individual tenancies.
The project developer, Fivex is a family owned company, which made it easier to push boundaries, general manager Lesli Berger says. “We’re not answerable to shareholders, so we thought, ‘Let’s test what is possible,’ he says. “We decided to do something that had a social benefit rather than just a private benefit – we didn’t expect any gain from it, although as it turns out it has been good for our reputation.”
However Berger says he was concerned the building’s green aspects might not sit well with potential tenants. But that is not the case – so far, the building has proved a commercial success and is already fully tenanted. The main occupant is the ANZ bank; other retail tenants include a hairdresser and an outlet of the fashion chain Cue.
“One of my fears was that the tenants would be scared and that we might lose deals because of it but we decided to go ahead anyway,” Berger says. “Fortunately, that fear has been misplaced – all the tenants like the concept. It’s been a positive.”
Even collecting sewage in a tank in the basement? “No one has raised that as a concern.”
‘SMH- The Essential: 22nd March, 2007’
Words Nick Galvin