Environmental Impacts of Multi-Storey Buildings Using Different ...

the GreenStar assessment considering the concrete building option to be optimal. The presumptionof GreenStar NZ and most green building rating systems is that recycled materials willautomatically result in reduced environmental burdens. However, this may not always be the caseand recycling in any given situation may be a positive or negative attribute. For example recyclingcan save landfill space, but the process of recycling of any given product may take more energyand adversely affect air quality more than production from raw materials. The focus on recyclingcan ignore the possibility and give more weight to solid waste and resource depletion issues thanglobal warming or other measures. One issue or indicator does not take precedence over theother, but commonly held assumptions can drive the shape of rating tools over data and facts whendecisions are made during tool planning. It may be prudent to re-visit the objective of recyclingduring the review phase of the GreenStar NZ tool to align the ratings to the initial aim to reduce theflows from and to nature.There were found to be aspects of the GreenStar NZ tool that were constrained when trying to fullyintegrate LCA-based tools into this building rating system. Two, in particular deserve emphasis; theproblem of data availability, and the absence of appropriate references or benchmarks againstwhich to judge LCA results for a particular building.GreenStar NZ is clear in its aims and in some cases is driving better practice; The energy creditsaim to reduce greenhouse emissions from operation of the building (carbon dioxide emissions), touse energy more efficiently and reduce peak loads. The reality is that energy rating is heavilydependent upon building fabric, building services systems and expected electrical and mechanicalloadings. In the majority of modern buildings there is a fine balance between natural light andthermal gain. The Façade is also an important factor in determining the final energy rating. Thissupports the notion that a more holistic measure is required to capture all these linked aspects ofthe energy equation. The material credits aim to minimise resource consumption through materialselection, use and re-use initiatives, support third party life cycle assessment programs andefficient management practices. There are gaps in the data currently available to populate thirdparty verification schemes such as Environmental Choice due to the lack of independently verifiedspecifications available through accredited suppliers. This is an active area of research and as databecomes available it will inform the GreenStar tools. Recycled steel and concrete at this stage arenot practical due to a lack of information available from suppliers and indeed a lack of choice ofproducts. In addition, as previously discussed, recycling may not always prove to be the bestenvironmental choice.The integrated interior fit-out strategy is important and does drive efficiency in management. Amajor limitation in the material category is the lack of environmental choice products for developersto choose from and be confident that they are making a sound decision.In order to encourage the uptake of LCA and incorporate all estimated effects and not proxymeasures it will be necessary to educate the public as to why informed environmental choice isimportant. It will be important to emphasise the need for assessing whole buildings and theinherent relationships in a building system where the choice of one material for an application maydictate the use of other materials for thermal or other reasons.Status Draft 16.07.2008Project NumberOur Ref − MWH Scion GreenStar Assessment PeerReviewFINAL.doc