The 60L Green Building in Melbourne is a leading example of how the environmental footprint (both construction and operational) of an office building can be minimised and still be a commercially-viable development.

As compared to a conventional Melbourne commercial office building, 60L can claim the following achievements:

• Only 30% of the typical energy consumption
• Only 20% of the typical mains water consumption
• Significant use of re-used, recycled and recyclable materials of construction
• Provision of a healthy, pleasant and productive workplace

Origins of the 60L project

In the 1990s the Australian Conservation Foundation (ACF) decided that it would use its own headquarters to create an example of best practice sustainable commercial building. So it partnered with ethical investment consortium, the Green Building Partnership, who purchased the site and constructed 60L in the existing brick warehouse, opening it in October 2002.

The Green Building Partnership owned and operated the 60L Green Building – with ACF as its largest tenant occupying a whole floor – until mid 2009 when it generously gifted the building to ACF to operate in perpetuity.

The 60L Green Building provides the fundamentals of smart design, open-plan layout, natural ventilation, lighting and energy efficiency.

60L has won a number of awards for excellence in sustainable design, including the Victorian Premier’s Sustainability Award 2003 and the Banksia Award 2003 (winner of Leadership in Sustainable Buildings category).

Materials

60L was constructed within the shell of an 1870s brick warehouse which allowed for the reuse of the brick walls and other materials. All new materials brought onto the site were then selected carefully for their environmental properties including:

• Recycled content, components or whole products where possible
• Non-toxic, low-chemical emissions products
• Durable, long-lasting materials
• Purchased from manufacturers who minimise the resources used and the impacts of creating their products
• Timber – mostly recycled (flooring, handrails of stairs, stair treads, all door and window frames, tops of balustrades etc). Any new timber has been from plantation pine
• Concrete – all new concrete contains about 60% recycled material (aggregate and fly-ash) 
• Steel – all reinforcing steel in the new concrete is recycled. No recycled steel has been used for the structure
• Bricks - either reused from the old building or second-hand bricks from off-site

Rainwater collection

Rainwater is collected from the upper roof of the building and its glazed atrium roof and stored in two 10,000 litre tanks on the ground floor. The combined roof collection area is about 1000 m2 so that for every 1mm rainfall, about 1000 litres of rainwater is collected into the two tanks. 60L has been able to collect and use about 400 kL every year. Rainwater supplies all fresh water needs in the building except for the emergency fire sprinklers, with three stages of micro-filtration removing any particulate material and large organisms, and a UV sterilisation unit killing any residual bacteria and other organisms.

Water efficiency

60L uses 1000 litres/day of potable rainwater and 2000 litres/day for flushing toilets and irrigation – a total of 3000 litres/day on average. This represents about 15 litres/day for a building population of 200 people – less than half of that for a conventional building. This is achieved by using rainwater and recycled water plus water efficient fixtures and fittings such as:

• Low flow taps and shower heads
• Low flush-volume toilet cisterns
• Water-less urinals

Healthy workplace

As well as building an environmentally sustainable office, a key objective of the 60L project was to create a healthy and pleasant work environment – and thus a more productive workplace. This is achieved through greater natural lighting, fresh air, a significant degree of local control over workplaceconditions (e.g. air-conditioning), reduced levels of toxic VOC emissions, a break-out area in the roofgarden, and the good feelings generated by working in an award-winning, environmentally responsible building.

A survey of 60L occupants carried out by an independent organisation found that more than 60% of building occupants had a perception that their own productivity had increased by at least 10% compared with their previous workplace. A separate survey conducted for the Australian Conservation Foundation of their 1st floor premises, found that the perception of workplace productivity had increased by more than 15% compared with their previous premises in Fitzroy.

Cycling

Tenants are encouraged to cycle to work (or walk or use public transport): there is no car-parking on-site and instead a large bike room provides secure storage. Showers are provided on each floor for cyclists to use. Cycling means less carbon pollution and is also a health benefit for tenants.

Green lease

A Green Building also requires the co-operation of tenants for it to operate efficiently and to ensure tenant office fit-outs are also efficient. 60L has a Green Lease agreement with all tenants to ensure they install energy and water efficient appliances and fittings, minimise chemical emissions, operate the building features such as air-conditioning, louvres, blinds and water systems efficiently, and educate their staff about the building.

Heating cooling and ventilation

60L uses automated louvres and thermal chimneys to maximise fresh air ventilation with minimal energy inputs and without the need for centralised air-conditioning.

The design includes a large central atrium which allows air to flow across tenancies from the light wells and into the atrium from where it is then vented to the atmosphere through four thermal chimneys. Computer-controlled louvre windows in all tenancies and on the chimneys operate according to outside air temperatures recorded by the roof top weather station. So, as the temperature drops in summer evenings, lourves open to let the cool air into the building. In this way, staff see the louvres as akin to the first blossoming of spring – warmer weather is coming!

Tenants can also control air flows through openable windows and louvres in the office areas. When outside temperatures are very hot or cold, tenants can use small domestic-sized, reverse-cycle air conditioners for heating or cooling their space. 

Renewable engery

Energy is sourced from both:

• On-site solar photovoltaic arrays and
• 100% new green power by 60L’s electricity retailer

Zero carbon pollution emissions have therefore effectively been achieved for operating the building, and the carbon footprint of the building’s construction has been offset by timber plantations on farms in the western district of Victoria.

Roof garden

The roof garden is a recreation space for tenants, which features local native plants and a vegetable patch as well as a shaded lunch area. The plants are watered via a subsurface irrigation system which uses water harvested from the roof. It also acts as an insulator from heat and cold for the floors below.

Energy efficiency

Energy consumption has been cut by the use of:

• The hybrid ventilation system (the combination of passive building design and individually controlled air- conditioners) instead of a central air-conditioning system
• A design for maximising daylight.
• Efficient lighting - T5-type fluorescent lighting (low energy input, high light output)
• Energy efficient office and kitchen appliances.
• Minimising use of the lift, with more prominent stairs
• Efficient use of water pumping system

It’s not hard to see why visitors to 60L – in particular those coming from heavily air conditioned and brightly lit standard offices – are often reluctant to leave the building, proving that sustainable office buildings provide far more than good outcomes for the environment.