Environment Canterbury Centre Development
Summary
Environment Canterbury began the development of its Christchurch office in 2001. The project involved redeveloping two existing office buildings and constructing a link building between them that provided a purpose-built regional Civil Defence Emergency Operations Centre. The redevelopment was completed in 2003.
At the initiation of the project it was clearly determined that the building was to showcase environmental leadership by demonstrating energy efficiency and environmental best practice in material selection, construction methods, material reuse and site waste minimisation.
Key drivers
The overarching driver behind the decision to develop the offices in a sustainable manner was Environment Canterbury's mission and staff values statement.
Environment Canterbury's mission statement is:
"We will achieve our vision by:
- Working in partnership with the communities in the Canterbury Region
- Promoting sustainable management of natural and physical Resources
- Using innovative, cost effective and technically excellent methods
- Ensuring that decision-making is based on high quality information."
The staff values statement reads:
"As staff of Environment Canterbury, our actions will be based on and guided by:
- The achievements of customer satisfaction and quality outcomes
- Respect for the needs, aspirations and values of individuals
- Openness, consultation and co-operation honesty, integrity and fairness
- Excellence, innovation and best practice
- Cultural awareness and sensitivity
- Environmental leadership by example."
As well as these overarching drivers, council is driven by its partnerships with other organisations such as its participation in the Building Research Association of New Zealand (BRANZ) Green Office rating scheme and Christchurch City Council's Target Zero Waste Construction Program.
Project detail
The architect produced a report on the environmental impact of building materials to provide council with the information required to make decisions on material selection (see Appendix 1). Materials were classified as best, next best, acceptable, worst or very worst.
For almost all the materials selected either a "best" or "acceptable" option was chosen. The decisions were made with a background that the building had to be constructed on a commercial budget and decisions were made relative to the impact on the overall budget.
The energy decisions were based initially on a six- year payback scheme with consideration being given to up to a ten-year payback. This meant that low energy products were purchased using a price premium where the premium would be paid back in energy savings in 6-10 years. All items with a ten-year payback were included.
A sample of the sustainable decisions incorporated into the building are:
- The use of timber framing preferred over steel studs due to the lower embodied energy. All the timber was sourced from a renewable plantation.
- Curtain walls with sun louvres and double-glazed windows to reduce energy consumption.
- Carpets and paints used were endorsed as environmentally preferable under the Environmental Choice Labelling Scheme.
- The use of PVCs was avoided, eliminating vinyl flooring which emit dioxins and isocyanides. Rubber and linoleum flooring was used in lieu of vinyl floorings.
- Polystyrene was only used if it was both CFC and HCFC free.
- Air conditioning systems use low ozone depleting refrigerants.
- Low risk timber treatments that were boron, chrome and arsenic free were used.
- Natural or water based low Volitile Organic Chemical (VOC's) paints and polyurethanes were selected.
- Woodboard products were specified to have low formaldehyde content.
- Woollen carpets were selected throughout work areas to absorb airborne pollutants such as formaldehyde.
- Where possible, existing building components were recycled for use in back of house areas. This included doors, ceiling tiles, and carpets.
- Cost effective and environmentally preferable acoustic insulation was made from 100% wool scraps. Woollen insulation in work areas also reduces the amount of particulate emissions common with glass fibre systems.
- The fabric for office pin board's was manufactured from 100% recycled plastic bottles.
- Modular carpet was installed that used 100% recycled fibres and 25% recycled backing.
- Thermal insulation was made from 60% recycled glass.
- Ceiling tiles were manufactured from recycled materials.
- Cement pavers were manufactured with recycled plastic aggregate and sit on a bed of crushed recycled glass.
The decision making process on construction methods was similar to that for construction materials outlined above. One example was the use of screw piles as opposed to driven piles. This reduced the amount of disturbance during construction to the neighbouring offices, hotel, and residential apartments.
Additionally, consideration was also given to post-construction environmental use of the building, with care taken to provide space for the collection and storage of recycled materials, i.e. paper recycling bins, a recycled materials storeroom and provision for waste separation in the cafe.
Key challenges
When selecting the materials council found that they were unable to use the "best" or "acceptable" options for electrical cable and drainage pipe. In the case of electrical cable non-PVC options are not readily available in NZ and although the drainage pipe is available at a competitive cost, the cost of jointing made this choice uneconomic.
In the case of recycling from the old buildings a survey was performed prior to the construction starting and any materials or fixtures that could be reused were identified and salvaged during demolition and stored for reuse or if possible were left in place and refurbished. The success of this was less than originally hoped as mixing and matching new and old materials was difficult and past construction methods can result in materials being damaged during the salvage process.
Council found they were fortunate in being able to select an architect that had overseas experience in environmental architecture and was able to import much of the product data needed to make decisions. One of the greatest challenges faced was being able to evaluate the lifecycle impacts of many products. The other barrier identified was the availability of products in New Zealand, forcing the choice between an environmentally sustainable imported product and a less preferred environmentally sustainable local product.
Outcomes of project
In the last 12 months an energy saving of 11% per m2 was achieved over the redeveloped complex when compared with the original building.
The building was used as a pilot scheme for the BRANZ Green Office rating scheme. The project was awarded a rating of "excellent", which is the highest possible rating. The BRANZ Green Office Scheme evaluation was an external audit of the project and gave council the confidence of knowing that the high standards of environmental leadership targeted were being achieved.
