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

- 108 -Workshop Limited provided expert energy modelling consultancy advice to this part of theproject.The simulation schedules for the buildings (occupancy, plug and lighting, and HVAC) areconsidered realistic and typical for a Christchurch office building.As described in Chapter 6, a life cycle inventory dataset for New Zealand was used tocalculate the primary energy content and the GWP for electricity. This dataset takes the NewZealand electricity mix as well as New Zealand specific emissions into account. Importantly,there is a high proportion of renewable energy in the electricity mix to clearly reflect theunique NZ situation (where up to 70% of electricity is generated by renewables, largelyhydro-power).As noted in the thesis, there is a tendency in simulations that the outcomes produced are lowerthan the audited energy consumption during occupancy. However, the average energyconsumption of 86 kWh/m 2 /yr for the buildings is well below benchmarks (for low energybuildings) and, thus, is considered appropriate as input data for the LCA.9.4.2 Material QuantitiesBoth the initial and maintenance embodied energy and GWP components of the LCA of thebuildings utilises the quantities of materials used in the initial construction and the ensuingmaintenance of the buildings over the 60-year life cycle.This research employed Davis Langdon Shipston Davies (Christchurch), a well-establishedand experienced, local quantity surveying company, to calculate and provide the quantities ofconstruction materials for each building design.The Quantity Surveyor produced material listings, from the structural and architecturaldrawings, as shown for all buildings in Appendix A. Any building of this magnitude isconstructed of many components and a very diverse range of materials. At the start of thisphase of the research, a decision was taken to itemise only those materials shown – whilst thismay be deemed an arbitrary listing, this was very much a considered decision taken inconsultation with all parties including the quantity surveyor. What was most critical was to‘capture’ and record all those quantities of materials which could have a significantcontribution to either the energy or GWP impacts. Thus, a material was considered forinclusion if it was either present in large quantities or it was a material or building componentwhich was very energy intensive (or emitted large quantities of GWP gases) in its production.The material listing could be further refined and many more categories included. However,the additional effort would involve a much greater level of detail than was available from thestructural and architectural drawings – and at much greater cost.The material quantities are also used to determine the environmental impacts of transport andend-of-life scenarios.The detail and accuracy of the material listings used in this research are considered to beaccurate, presented at an appropriate level of detail and exceed the original projectspecifications.