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    Policy implications of time-differentiated climate change analysis in life cycle assessment of building elements in Aotearoa New Zealand
    (Springer-Verlag GmbH, 2025-03-21) McLaren SJ; Elliot T; Dowdell D; Wakelin S; Kouchaki-Penchah H; Levasseur A; Hoxha E
    Purpose: Climate change policies are increasingly including time-dependent carbon targets for different economic activities. However, current standards and guidelines for climate change assessment of buildings ignore these dynamic aspects and require use of static life cycle assessment (LCA). This research investigates how to better account for the timing of greenhouse gas (GHG) emissions and removals in LCAs of buildings and construction products, using a static and dynamic LCA case study of roofs, walls and floors in Aotearoa New Zealand residential dwellings. Methods: Static and dynamic LCA methods were used to assess the climate change impact of two assemblies each for external walls, ground floors and roofs used in stand-alone residential dwellings in Aotearoa New Zealand. Each assembly was modelled for a life cycle extending from material production, through to element construction, operational use, and final end-of-life treatment. Results were calculated as total GWP100 results for each life cycle stage, GWP100 results disaggregated into time periods, and as instantaneous and cumulative radiative forcing up to year 190. Sensitivity analysis was undertaken for the building reference service life, exposure zone, location, and end-of-life treatment. Results and discussion: Four time-related aspects were found to be particularly significant as regards their contribution to the final static LCA (sLCA) climate change results: -Inclusion versus exclusion of biogenic carbon storage in landfill -Modelling of end-of-life recycling activities using current versus future low or net zero carbon technologies (in module D) -Building reference service life (50 versus 90 years) -Choice of modelling parameters for landfilled timber and engineered wood products. Use of dynamic LCA (dLCA) enabled priorities to be identified for climate change mitigation actions in the shorter and longer term, and showed that half of the assemblies achieved net zero carbon by year 190 (timber wall, steel wall, timber floor). Conclusions: Timing of GHG emissions and removals should be included in LCAs to support decision-making in the context of achieving targets set in climate change policies. In particular, LCA results should show ongoing biogenic carbon storage in landfilled timber and engineered wood products. Carbon footprint standards, guidelines and calculation tools should be prescriptive about building and construction product reference service lives, the EofL fate for different materials/products, and modelling of forestry and landfill activities, to provide a level playing field for stakeholders.
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    Comparative analysis of the productivity levels achieved through the use of panelised prefabrication technology with those of traditional building system : a thesis submitted in fulfilment of the requirements for the degree of Doctor of Philosophy (PhD) in Construction, School of Engineering & Advanced Technology, Massey University, Albany, New Zealand
    (Massey University, 2016) Shahzad, Wajiha
    Several studies have documented benefits of prefabricated building system compared to the traditional approach. Despite the acknowledged benefits of refabrication, its application is generally low in the New Zealand construction industry. This low uptake is largely attributed to the fact that the documented benefits of prefabrication technology are anecdotal, or based on investigations of isolated case studies. This study aims to contribute to filling this knowledge gap by analysing cost savings, time savings, and productivity improvement achievable by the use of panelised prefabrication in place of the traditional building system. A two-phased mixed method of research was adopted for the study. The first phase involved the use of case study-based archival research to obtain qualitative data from records of 151 completed building projects in three cities of New Zealand – Auckland, Christchurch and Wellington. The second phase involved the use of questionnaire survey to obtain feedback from industry stakeholders. Results showed that the use of panelised prefabrication in place of traditional building system contributed to 21 percent cost saving, 47 percent time saving and 10 percent average improvement in the productivity outcomes in the building projects. Results further showed that 17 factors could significantly influence the levels of benefits achievable with the use of prefabrication technology. ‘Building type’ and ‘location’ were the factors having the most significant influence on the benefits achievable by the use of panelised prefabrication in place of the traditional building systems. Other factors that influence the benefits of prefabrication included (in diminishing order of influence): logistics, type of prefabrication, scale/repeatability, standardisation, contractor’s level of innovation, environmental impact, project leadership, type of procurement, whole of life quality, site conditions, site layout and client’s nature.
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    Time flow and reversibility in a probabilistic universe : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Philosophy at Massey University
    (Massey University, 1990) Holster, Andrew Thomas
    A fundamental problem in understanding the nature of time is to explain its 'directionality'. The commonplace view is that this directionality is provided by the 'flow of time'. Unfortunately this concept of 'time flow', which seems to make perfect sense to us in our everyday lives, has resisted philosophical and scientific analysis so well that today it is widely regarded as having no place in the scientific account of the world. Instead, various alternative physical concepts of the directionality of time have been developed, principally the notions of the time reversibility of physical laws or theories, and of the time asymmetry of physical processes. It is frequently argued by philosophers of physics that the scientific account of the directionality of time must be framed entirely in terms of these physical notions. The thesis of the present work is that this conclusion has been reached far too hastily. It is argued that the concept of time flow is a legitimate physical concept, and furthermore, that time flow plays a real part in quantum theory. A number of conceptual investigations are necessary to support this argument. Firstly, it is necessary to give an analysis of what a physical theory of time flow might be like, and how it might be empirically established. This is given in Chapter One, which at the same time is an overview of the results of later chapters. It is found in Chapter One that the concept of physical time flow has an important connection with the concept of time reversibility, which makes it necessary to give an analysis of this notion. A detailed discussion of reversibility and time symmetry is given in Chapters Two to Five. Here it is demonstrated that the orthodox analysis of the reversibility of probabilistic theories is flawed. This conclusion allows it to be shown, in Chapter Six, that, contrary to current scientific belief, quantum theory is profoundly irreversible. This result, together with the argument of Chapter One, allows a strong prima facie case for an interpretation of quantum probabilities as involving time flow to be given. However, because of the traditional problems with the notion of time flow, for this interpretation to become respectable it needs to be demonstrated that it is possible to construct a formal model of a physical ontology in which time flow can be represented. This is undertaken in Chapter Seven. In Chapter Eight, various points about the role of probabilities in quantum theory are discussed. Finally, in Chapter Nine, the implications of relativity theory for the proposed theory of time flow are considered. It is found that relativity theory poses a serious problem for a physical theory of time flow, but the implications of relativity theory for the proposed interpretation of quantum probabilities is not clear because of deeper foundational problems with quantum theory.
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