More Efficient Office Buildings – Retrofitting is really possible

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We often hear about recently constructed buildings in Canberra that meet high levels of energy efficiency, and these days they are rated using the Green Star Rating. For example, the first Green Star-rated building in Australia was 8 Brindabella Circuit at the Canberra Airport (obtaining 5 stars ‘as built’).

New Buildings are one thing, but what about the majority of existing office buildings in Canberra? They were built decades ago when there was less concern about environmental footprints. Surely we can’t re-build them all with new buildings… so what improvements are possible?

Local company Australian Ethical Investment took on the challenge a few years ago – and refurbished their office building – in flying colours. The company’s commitment and core business are to help people invest their money ethically. So it has applied this philosophy in choosing business premises.

When it completed its refurbishment in 2007 it became the first building to obtain a 6 star rating in the ACT, (and only the third such building in Australia) from the Green Building Council of Australia.

Australian Ethical sought the views of its staff in planning for the retrofit and set the objectives of reducing energy and water use, minimising waste, and enhancing staff comfort and productivity.

So what is better about it?

Its Healthy and Comfortable

Four dimensions of the refurbishment reflected this aim:

  • Better access to natural light:
    • Four internal ‘stacks’ with glass brick sides to allow natural light into (and to allow hot air to exit from) the middle of the first floor
    • Opened barrel vault roof, installed louvered windows and a cathedral ceiling
    • Limited internal office partitioning
  • Better access to natural ventilation with windows that can be opened
  • Greater feeling of warmth in winter by using hydronic radiators, and coolness in summer by exposing and insulating the slab downstairs to avoid the need for mechanical cooling
  • Improved indoor air quality, through use of low VOC (volatile organic compounds) emissions paint and sealants, low VOC emissions reconditioned (post-consumer) carpet, and very low formaldehyde composite wood products

It uses much less energy

Estimated 75% reduction in CO2 emissions compared with estimates for previous premises and for average Canberra office buildings.

These features help to save energy and reduce ongoing green house gas emissions:

  • Passive cooling and ventilation in summer by purging hot air from the building at night
  • A wider temperature range inside the building (eg 19 degrees in winter and 26 degrees in summer) to reduce demand for mechanical air conditioning
  • Double glazing of windows
  • External walls are ‘reverse brick veneer’ – thermal mass on the inside is insulated (75mm) from the outside air temperature
  • R5 insulation under the metal deck roof
  • Improvements to the shading panels
  • Exposing the ground floor slab
  • Evacuated tube solar hot water heating

It uses less water

Estimated total draw on mains water:

9.24L per person per day

Estimated 75% reduction in water use

Water efficient features incorporated into the building included:

  • Taps upgraded to 4 litre discharge per minute, showerheads to 6 litres per minute (compared to average tap discharge 15-18 litres per minute, showerhead 15-25 litres)
  • Upgrade of the existing single flush toilets to dual flush with a 9/4.5 litre system
  • Urinals upgraded with a Sani-Sleeve low water use system reducing water use by 95%
  • Rainwater tanks collecting from the roof and plumbed for use in flushing the toilets
  • Garden drip irrigation with moisture sensor

Less Waste in Retrofitting

Recycling rate for the project of >80% by weight

Use of recycled materials was a key feature:

  • Glass blocks used in the original structure were reused for the stacks and wall partition;
  • 250m2 of carpet tiles were reused
  • All ceiling tiles used were already on the site
  • Noise insulation in the ceiling from the old fit out was reused in partition walls
  • Metal shade structures were re-modelled and repainted
  • Floor tiles in the old computer room were painted and reused for wall decoration
  • Reused large quantities of v-jointed plasterboard, doors and air conditioning ducting
  • Materials which could not be reused were, in general, sent to recycling

Australian Ethical Investment is involved actively in the community, donating 10% of its profit to useful charitable, benevolent and conservation projects.

On 26 June 2011, Australian Ethical is organising a Smart Living Festival (click for details) in Canberra that aims to celebrate the best of Canberra’s sustainable living initiatives.  For more information on their building – see the Australian Ethical Investment Website

 

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