Environmental management plan for construction

Sustainable building design involves a total life cycle approach. That is to say that attention must be given to all the potential environmental impacts that can occur during the construction and the ultimate demolition phase of a building, as well as the ongoing impacts of daily operation. The EcoCentre incorporates this life cycle approach. This began even before building work started with the preparation of an environmental management plan, which ensured best practice standards of work in areas such as:

• Minimisation of noise and vibration
• Minimisation of waste and its efficient management
• Control of erosion and sediment
• Dust mitigation and control of airborne emissions
• Rehabilitation of the building site and landscaping

An independently commissioned environmental audit of construction works at the site was undertaken and found a very high level of compliance with the management plan.

Other features that minimised the impact of the EcoCentre at time of construction included:

• The curving plan of the building followed the contours of its basin-shaped site and maximised tree preservation during construction.
• The building’s bolted-steel, pole frame was pre-finished before erection. This degree of prefabrication is unusual for a building of this size and meant that the size of lifting gear required to place the frame on site could be reduced. This also reduced the amount of concrete footings required to secure it.
• Non-toxic materials were used in construction to facilitate recycling of the building at the end of its life. The steel frame and floor panels can be unbolted, the rammed earth walls demolished, and materials from the timber trusses, windows and roofing reused.

Minimisation of resource use

Material and energy flows through a building in the course of its daily use are a major part of its impact upon the natural world. In line with a key principle of sustainability, the need to live more lightly on the Earth, the design of the EcoCentre building minimises environmental impacts in a number of ways.

Lighting and temperature

A high level of natural lighting has been achieved inside the building through the use of glass picture windows and heat and glare reflective 'smart' glass panes in the gallery. This has eliminated the need for artificial lighting during the day and reduced electricity demand in all but the most overcast of conditions. Energy efficient compact or strip fluorescent lights are used when this happens. Smart glass is produced by sandwiching layers of glass and special plastics together. When combined with forms of natural ventilation and the correct orientation of the long axis of the building in relation to the passage of the sun overhead, smart glass can contribute to the control of building temperature.

Energy generation

A photovoltaic system on the roof of the EcoCentre converts the energy of sunlight into DC electricity through 72 Canon Econoflat modules made from amorphous silicon. This power is then converted to alternating current by inverters housed under the building. The resulting energy is fed into the electricity grid supply of the Nathan Campus.

The photovoltaic panels have peak output of 4 kilowatts at maximum sun strength, and are expected to produce an average daily electrical output of about 20 kilowatts hours (equivalent to an annual total of approximately 7Mega Watt hours). A real time record of the solar electrical power being generated is displayed on a computer within the building.

Rammed earth walls

Eight rammed earth walls in the EcoCentre help stabilise interior temperatures. Due to their mass, the walls tends to absorb heat in summer and act as a heat sink. In Winter, the same mass will release radiant heat absorbed from the sun in the early hours of the day. This helps to control temperature fluctuations. These walls are also a major design feature inside the building. They were made from clay excavated near Mount Cotton not very far from the construction site. The clay was mixed with a binding agent and hand rammed on site in large wooden moulds, the imprints of which can be seen on close inspection.

Ventilation

A high level of natural ventilation is achieved through a combination of louvres on the ground and gallery levels. The height difference between the two levels of louvres helps air move by convection, with the upper louvres opening and closing automatically according to wind direction. Lower pressure is created on the downwind side of the building and air is sucked through interior spaces to create a ventilation flow. Electronic sensors close the gallery louvres automatically in conditions of high wind or penetrating rain. These design elements help create comfortable interior temperatures under most conditions with a reduced need for air conditioning and, thus, electrical power.

Water conservation

Any rain that falls on the uphill side of the EcoCentre roof is collected in a split-level, two-tank water storage facility under the building. This tank water is used for toilet flushing and non-potable water use in the hand basins. The tank system switches automatically back to mains water supply in times of low rainfall. This system represents a potential saving of 357, 000 litres of water per year.

A wet composting system takes sewerage and greywater from the toilets, hand basins and shower and passes it into a digester tank. Here worms and micro-organisms break it down to form a solid material that can ultimately be used for soil enrichment. The digester is also capable of receiving compost materials such as food scraps, paper and cardboard. Liquid waste from the digester is pumped to an activated sand filter bed. This renders the effluent fit for pumping to under-soil irrigation pipes to restore water flow to the forest.