Waitakere Central

Waitakere Central - Sustainable Design at Waitakere City Council's Civic Centre

Waitakere Central

Waitakere Central is a showcase for practical environmental design. It integrates architecture, engineering, art and urban design to demonstrate the eco city's sustainability principles.

Siting and Orientation

Louvres minimise glare on the administration wing's north face.

The key to the Waitakere Central development is its location in the heart of Henderson, one of Waitakere's three main town centres.

The council building anchors town revitalisation, supports sustainable transport, promotes economic development and epitomises the Eco City's sustainability principles.

When the council brought staff together from several scattered locations onto a site alongside the redeveloping Henderson railway station in 2006, it made the $36 million, 13,400 m2 civic centre a showcase for practical green design.

The council also demonstrated the focus on town centres and transport hubs outlined in its growth management strategy.

By placing its 700 staff alongside the town centre, the council supported nearby retailers and provided a link and critical mass for development of the other side of the railway tracks.

The building's covered entrance adjoins an airbridge to the train platforms, bus interchange and roadway. The council and railway network owner integrated the new railway platforms and station into the centre's design.

Waitakere City hired architects and consultants who used the council's Better Building Code to ensure economical running costs through energy efficiency.

The administration wing is a six-storey rectangular building that houses the public interface facilities and council staff, mainly in open-plan offices.

The civic wing houses the mayor, directors, council chamber and meeting rooms.

The buildings face each other across a glazed bridge that provides direct sheltered access to the railway platforms and bus interchange, linking with the town centre beyond.

The administration wing's long rectangular shape minimises the surface area exposed to the low eastern and western sun, to avoid overheating.

The glazed northern side has metal louvres to prevent overheating and minimise glare, while admitting natural light.

Glazing is with high-performance low-emissivity glass.

The colder southern side has brick cladding and smaller windows, to limit heat loss.

A wide staircase that sweeps across five of the floors on the building's northern face provides a buffer between inside and outside, admits natural light, circulates air and encourages staff to take the stairs instead of the lifts.

Transport

Henderson railway station is integrated with the council building.

Energy efficient lighting.

Waitakere Central's site was deliberately chosen to be near the Henderson town centre and next to the western railway line's Henderson station and a bus interchange. The council paid for the upgraded railway station to be connected to the council buildings with a glazed bridge, escalators, lifts and stairs.  The bridge also provides sheltered access for rail travellers to cross the tracks to the platforms.

The location gives staff and visitors more sustainable transport options. For the public, a visit to the council can be combined with a trip to the shopping centre. Through the council's workplace travel plan, staff have been offered incentives to use public transport, cycle, walk or carpool. The number of staff carparks has been deliberately reduced, with priority given to those who share rides. Secure cycle storage facilities and nearby showers encourage cycling.

Energy

Waitakere Central has been designed to an annual energy consumption target of no more than 100 kilowatt-hours per square metre of occupied floor space. To achieve this, it was important to replace some electric lighting with daylighting. The interior surfaces are pale and simple, to reflect light. This, and a long, narrow floor plan that faces north, makes good use of daylight.  The electrical circuits have been designed in zones so lights switch off around the administration wing's perimeter if enough daylight is coming in. The controller also dims lights in response to rising levels of natural light. Office lighting is by energy efficient T5-type fluorescent lamps with electronic control ballasts. The lamps have reduced mercury content and are recyclable.

The control system has pre-programmed strategies for automatic monitoring of the occupied areas, scheduling by time clocks, and controlling the zones that can be selectively switched on and off.  Appliances have been chosen for their energy star rating, and when computer monitors are due for replacement, low-energy LCD screens are being installed. The lifts are energy-efficient and do not require a machine room.

Climate and Air Handling

The buildings have been designed to keep conditions comfortable with a minimum of supplied energy. Ideally, the ventilation and air supply would be natural, through opening windows, but the nearby railway station makes this impractical - a certain amount of mechanical air conditioning is needed.The buildings are insulated to twice the Building Code requirement. The administration wing's uncovered concrete structure keeps temperatures steady by slowly absorbing and releasing heat. The exposed concrete ceiling beams are hollow and act as pipes, distributing cool air to circular vents installed flush with the carpeted floor above. The air rises as it collects heat from sources such as people and computers, setting up a flow that draws in more cool air. This displacement ventilation system doesn't need large fans, and the incoming air needs less chilling, so it uses less energy than typical office air conditioning. A high proportion of the air supply can come from fresh outside air that doesn't need chilling - another way to save energy.

A reverse-cycle air-to-water heat pump chiller provides heating or cooling. It re-uses waste heat from outgoing or incoming air. During the night, the computer-based building management system pre-cools the building using night air.

The administration wing has a Swift domestic-size wind turbine, installed by network company Vector as a demonstration of distributed renewable energy.

Water

Waitakere Central is set up to collect rainwater from the roof, use it efficiently and then dispose of it responsibly. Rainwater falling on the site is either collected from the roof and stored, or flows from the paved areas into planted areas that filter the water and slow its entry into the stormwater system.

To minimise the need for watering, the landscaping uses drought-tolerant native plants. Water collected from the 1500m2 administration wing roof is stored and re-used for flushing toilets, and is piped to architectural water features. The storage capacity is 37,000 litres, enough for the toilets in the administration and civic wings. The civic wing has a 500m2 'green roof' where plants grow in a substrate of clay pellets on a waterproof membrane. The roof acts as a buffer for rainwater and filters it, while providing insulation.

Hand-basin tapware designed for low water use has built-in infra red sensors to provide only enough water as needed. The administration and civic toilet blocks have waterless urinals. The administration rooftop supports six solar panels that heat water for toilet blocks, showers and kitchen. Electric boosters back them up. Another toilet block has water heated by a heat pump.

Materials

The floor plan of the administration wing is designed for flexibility and changes of layout with minimal waste of materials. Concrete, steel, glass and timber have been left in as natural a state as practical, with minimal paint and other finishes. This avoids the need for repainting and reduces air pollution from off-gases. Materials were selected for their environmental qualities. In the council chamber, hoop pine acoustic panels were sourced from sustainable forests. The carpet tiles are a carbon neutral produce. If damaged or worn, tiles can be replaced individually. The louvres for the council chamber and administration wing are set at an angle to control sun and glare.

The building management system controls the council chamber's blinds, which can be pre-programmed to close at certain times of the day. One layer of blinds reduces glare and heat transfer and provides, shade, while the other offers a total blackout for multimedia presentations.

Waste

Food scraps are collected to feed tiger worms at the on-site worm farm. Paper wastage in office printing is minimised by making double-sided printing the default option. The copy is printed only when the staff members goes to the printer and swipes an identity tag. Staff can also scan items at the copiers and send faxes directly from their computers. Paper, recyclables and polystyrene packaging are separated at source and collected for recycling.

The loading bay and office floors and kitchens were designed to accept recycling facilities.

Art

Waitakere City Council wanted art to be a prominent part of Waitakere Central. Consultant artists Kate Wells and Matthew von Sturmer worked closely with the architects, iwi and council staff to integrate arts into the building. Here's a selection of the artworks that can be viewed in the civic wing and public areas:

On the wall of the entry stairs, a sculpture carved by Louise Purvis from white Italian marble is inspired by a contour map of the Henderson Valley and its streams.	A four-metre-high basalt and sandstone obelisk by Karekare sculptor John Edgar marks the point of transition between the JapaneseGarden and the Civic Square.	At the base of the stairs at the main entry stands a nine-metre-high pou whenua designed and crafted by Te Kawerau a Maki carvers John Collins and Sunnah Thompson. Te Kawerau a Maki is the local iwi.	Karekare artist and Waitakere arts laureate Ann Robinson created the two glass flax pods for the civic wing's entry foyer. They were made using the lost wax casting technique.
At the public counter in the administration wing, botanical specimens painted on glass screens were made by Titirangi artists Tabatha Forbes. They are based on a series of paintings of specimens collected locally and documented by Waitakere-born botanist Lucy Cranwell-Smith.	The civic chamber houses facsimiles of two versions of the Treaty of Waitangi - the Waitangi version (left) and the Waikato version (right), as a symbol of the council's commitment to the treaty and the ongoing partnership with local iwi.	For the handrails on the grand staircase along the north of the administration wing, sculptor Matthew von Sturmer cast bronze inserts that represent the native plants typically found on a journey from the west coast beaches to the peaks of the Waitakere Ranges. Plants include grasses, pohutukawa, ponga and kauri.	The window at the eastern end of the link bridge displays a large translucent print of a painting by Karekare artist Dean Buchanan. He painted the image of the Pararaha wetland specifically for the stained glass-effect window.
Titirangi artist Anna Crichton designed the carpet on the level of the civic wing that houses the council chamber. She was inspired by the patterns in a cross-section of a ponga tree.	High on the civic chamber's curved wall is the Matariki group of stars, carved by Sunnah Thompson, cast in bronze and mounted with concealed blue LED lighting. The appearance of Matariki marks the Maori new year.	The council commissioned artist Allie Eagle to research and produce a large heritage-based painting for the level two foyer in the civic wing. She worked closely with a group of other artists to complete the 14m2 painting, which refers to local history from the first settlers to current figures.	Council employees were invited to take photos representing life in Waitakere City, to celebrate the opening of Waitakere Central. The photos have been assembled into montages displayed on four levels of the western stairwell.

Image Gallery 

Secure bike storage provides an incentive for staff to cycle.	The grand staircase encourages staff to walk instead of taking lifts.	The civic wing's 'green garden' slows the flow of rain.
Vector Ltd's Swift 1.2kW household wind turbine.	Cool air diffuses into the office space from grilles in the floor.	One layer of blinds provides shade and the other offers a blackout.

Credits

• Architect Architectus, with Athfield Architects
• Structural and civil engineer Alan Reay Consultants
• Mechanical and electrical design Connell Wagner
• Construction Canam
• Traffic planning & design Traffic Design Group
• Landscape architect Wraight & Associates
• Electrical contractor Aden Electrical
• Mechanical installation Airpro
• Mechanical supplier Cooke Industries
• Lead artists Matthew von Sturmer, Kate Wells