New Zealand’s greenest building

19 February

Christchurch’s new Civic Building has been awarded the highest possible rating for environmental design by the New Zealand Green Building Council.

The New Zealand Green Building Council has announced today that the joint venture –Ngāi Tahu Property and Christchurch City Council – Civic Building has been awarded the maximum six Green Star Office Design rating, achieving a record 83 points under the Green Star rating system.

“With six Green Stars and 83 points we have designed the greenest building in New Zealand,” says Christchurch Mayor Bob Parker. “This represents significant annual energy and cost savings for our ratepayers and reflects the Council’s commitment to creating a sustainable future for our community and the region.”

Te Rūnanga o Ngāi Tahu Kaiwhakahaere Mark Solomon says Ngāi Tahu Property and the Council are continuing to demonstrate levels of excellence that can be achieved with a public-private joint venture. “The Council and Ngāi Tahu Property are on the cusp of completing a building that we can all feel justifiably proud of.”

Work on the building remains on time and on budget, with the Council beginning to move into the renovated and refurbished Hereford Street premises from 13 August.

Green Star is a national, voluntary environmental rating scheme that evaluates the environmental attributes and performance of New Zealand’s buildings. It was developed by the New Zealand Green Building Council (NZGBC) in partnership with the building industry.

Mayor Parker says sustainability was a prime consideration for the new building for both partners. Early in the process it was agreed the design needed to adhere to the guiding principles of the Green Star rating system.

Chair of the Civic Building Joint Venture Gill Cox says the council was hoping for at least five stars. “It’s great to have exceeded expectations by achieving a Six Star rating within the approved budget.”

The Green Star system evaluates the environmental attributes and performance of buildings in nine categories – management, indoor environment quality, energy, transport, water, materials, land use and ecology, emissions and innovation – to assess its environmental impact. This process is managed by the New Zealand Green Building Council; developers having to submit detailed submissions for assessment.

One of the outstanding features of the new Civic Building is the installation of a tri-generation system. The system means the building generates its own electricity from a renewable energy source – biogas. This is piped from the Council’s Burwood landfill site – and in future years from the city’s Wastewater Treatment Plant – and converted into electricity. This process is used to heat and cool the building with annual energy savings of about $1.3 million.

Additional energy savings come from energy-efficient light fittings, automatic daylight dimming, occupancy controls and sensors on the escalators, which will activate only when people approach, and regeneration capabilities on the lifts.

To the north, the building has a double-skin façade and between is a thermal and solar buffering zone. This façade will also be used to vent air and heat from the building, enhancing its thermal properties. Within the office floors a monitoring system detects when carbon dioxide (CO²) has reached a certain level and automatically introduces fresh air through floor vents.

All materials used in the building have been chosen for their low environmental impact such as low emission paints, carpets, adhesives and sealants, and a 60 per cent reduction in the use of PVC, contributing to a healthy working environment.

Rainwater harvesting is expected to provide one million litres of water annually. It will be used to flush the toilets, for landscape irrigation and a water feature. Solar power will provide 85 per cent of the building’s hot water.

The decision to reuse an old building rather than build from scratch represented an embodied energy saving of 65,700 gigajoules – equivalent to a saving of 6440 tonnes of CO² emissions or 12,800 return flights from Christchurch to Auckland.

The target for waste recycling from the building was 70 per cent. In January 2010, the project was achieving 88 per cent recycling for demolition and construction materials – a phenomenal achievement by contractors Hawkins Construction.

Mark Solomon says, “The building will provide the council with a front door that will show residents and visitors alike what it means to be truly sustainable and visionary.”

Mr Parker says, “We’ve taken an unattractive building and transformed it. It is my expectation that we will see more and more refurbished and redeveloped buildings in New Zealand meeting these extraordinarily high Green Star standards, but it is wonderful to be the top achiever.”

Mr Cox extended his congratulations to everyone involved including Ngāi Tahu Property Development Manager Gordon Craig and the project consultants, Athfield Architects, Powell Fenwick Consultants, Rider Levett Bucknall, RCP and Ecubed Building Workshop, together with the contractors Hawkins Construction.