Surveying & Built Environment Vol. 22 Issue 1 (December 2012)

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Based on the above, it appears that there is lack of a detailed holistic approach for examining all aspects of gaseous emissions of a construction project across a Building Life Cycle. Therefore, the aim of this paper is to build a model for calculating gaseous emissions from energy consumption during a Building Life Cycle. The model can help evaluate the impact of implementing building projects on air quality. From this evaluation strategies can be devised to reduce the total Building Life Cycle environmental impact. MAIN ElEMENTS duRING A BuIldING lIfE CYClE Buildings go through many periods during their useful life. From the initial conception to final recycling, re-use or demolition of a building, a whole range of processes must be taken into account when assessing a Building Life Cycle (Cole and Kernan, 1996). An assessment of the environmental impact of any building has become a major research discipline, with the aim of providing more complete information Surveying and Built Environment Vol 22, 61-73 Nov 2012 ISSN 1816-9554 about the relationship between a building and the environment. Nevertheless, life cycle thinking is required for any proper and thorough assessment of the environmental effects of a building. According to the United States Environmental Protection Agency (EPA), the product life cycle is divided into three major phases: i) cradle to entry gate phase; ii) entry gate to exit gate phase; and iii) exit gate to grave phase. A building is also regarded as a product, and its life cycle is from materials acquisition to waste disposal (United States Environmental Protection Agency, 2006). In this paper, the cradle to entry gate phase of a building refers to the process of manufacturing and transporting building materials before they actually reach the construction site. The entry gate to exit gate phase refers to the processes of construction. The exit gate to grave phase refers to all the processes involved in building operation, maintenance and repair works, and then in the post-operational period, demolition and disposal of waste. Accordingly, there are seven main elements in the life cycle of a building, as shown in Figure 1. figure 1: Seven main elements during building life cycle SBE 63
SBE 64 Modelling Gaseous Emissions from Energy Consumption during Building Life Cycle ClASSIfICATIoN of GASEouS EMISSIoNS duRING THE BuIldING lIfE CYClE There are various classifications of gaseous emissions from buildings. According to the Hong Kong Environmental Protection Department (Environmental Protection Department, 2009), the emission inventory consists of five major gaseous pollutants, namely: sulphur dioxide (SO 2), nitrogen oxides (NO X), respirable suspended particulates (RSP or PM 10), volatile organic compounds (VOC) and carbon monoxide (CO). Under the Clean Air Act (United States Environmental Protection Agency, 2006), the US EPA establishes air quality standards to protect public health and the environment. The US EPA has set the national air quality standards for six common gaseous pollutants (also called the criteria pollutants): NO 2 (nitrogen dioxide), O 3 (ozone), SO 2, PM, CO, and Pb (lead). The United Nations Framework Convention on Climate Change considers CO 2, CH 4 (methane), N 2O (nitrous oxide), PFCs (perfluorocarbons), HFCs (hydrofluorocarbons), SF 6 (sulphur hexafluoride) as direct greenhouse gases, and SO 2, NO X, CO, NMVOC (non-methane volatile organic compounds) as indirect greenhouse gases (United Nations Framework Convention on Climate Change, 2004; United States Environmental Protection Agency, 2006). O 3 is not directly emitted, but is formed when NOX and VOCs react in the presence of sunlight (Colorado Department of Public Health and Environment, 2007). In general, the total quantities of PFCs, HFCs and SF 6 produced by energy consumption are much less than the other three direct greenhouse gases. For example, in 2007, the total weight of CO 2 emitted in Hong Kong was 40,000 kilotons while the number of PFCs, HFCs and SF 6 added up to only 0.590 kilotons (Environmental Protection Department, 2009). The quantity of Pb emission is also small compared to SO 2. In Hong Kong, for example, the national lead emission in 2002 is 1,663 kilotons, while the quantity of SO 2 is as large as 14,581.911 kilotons (Census and Statistics Department, 2008). Based on the above understanding, the typical gaseous emissions during the Building Life Cycle include CO 2, CH 4, N 2O, SO 2, CO, NO X, NMVOC and particulates (as shown in Table 1). These emissions exist across all periods of the Building Life Cycle (Zhang et al., 2012).
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Information All rights reserved. No
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SBE 4 Contents Editorial Articles A
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SBE 6 documents (Hong Kong Special
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SBE 8 A Note on British Blockhouses
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SBE 10 A Note on British Blockhouse
Page 13 and 14: A Note on British Blockhouses in Ho
Page 15 and 16: SBE 14 A Note on British Blockhouse
Page 21 and 22: SBE 20 Reconstructing The Early His
Page 39 and 40: SBE 38 Good Property Valuation in E
Page 63: SBE 62 Modelling Gaseous Emissions
Page 67 and 68: SBE 66 Modelling Gaseous Emissions
Page 75 and 76: SBE 74 direct Geo-referencing and o
Page 77 and 78: SBE 76 Direct Geo-referencing and O
Page 89 and 90: SBE 88 Kadoorie Hill and footnote 4
Page 91 and 92: SBE 90 Kadoorie Hill and Footnote 4
Page 93 and 94: SBE 92 Definitions of Land Use Term
Page 95: SBE 94 Definitions of Land Use Term
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Surveying & Built Environment Vol. 22 Issue 1 (December 2012)

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