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Background, Aim and Scope:
To minimize the environmental impacts of construction and simultaneously move closer to sustainable development in the society, the life cycle assessment of buildings is essential. This article provides an environmental life cycle assessment (LCA) of a typical commercial office building in Thailand. Target audiences are architects, building construction managers and environmental policy makers who are interested in the environmental impact of buildings.
Materials and Methods:
In this work, a combination of input-output and process analysis was used in assessing the potential environmental impact associated with the system under study according to the ISO14040 methodology. The study covered the whole life cycle including material production, construction, occupation, maintenance, demolition, and disposal. The inventory data was simulated in an LCA model and the environmental impacts for each stage computed. Three environmental impact categories considered relevant to the Thailand context were evaluated, namely global warming potential, acidification potential and photo-oxidant formation potential. A 50-year service time was assumed for the building.
Results:
The results obtained showed that steel and concrete are the most significant materials both in terms of quantities used, and also for their associated environmental impacts at the manufacturing stage. They accounted for 24% and 47% of the global warming potential respectively. Additionally, of the total photo-oxidant formation potential, they accounted for approximately 41% and 30%; and, of the total acidification potential, 37% and 42% respectively. Analysis revealed that the operation phase of the selected building contributes a considerable share of environmental impacts.
Discussion:
The environmental consequences of increasing the indoor set-point temperature of the building by 2°C was also evaluated. This resulted in a corresponding reduction of 820 tons CO2 per year, 3.37 tons SO2 per year and 8.90 kg of C2H4 per year. For the entire office building stock in Thailand increasing the set point temperature by 2°C could result in a reduction of 7.1 x105 tons CO2 per year, 2.9 x 103 tons SO2 per year and 7.7 tons of C2H4 per year respectively. On a national scale, if this strategy is implemented in combination with load shedding by switching off office equipment, lightening as well as air-conditioning systems during 1 hour lunch breaks, reductions of about 10.2 % in global warming potential, 5.3 % in acidification potential and 0.04% in photo-oxidant formation potential per year can be achieved from the power generation sector. Overall, both measures have the potential to reduce approximately 4% per year from the projected global warming potential of 211.51Tg for Thailand’s economy. Encouraging the operation of office building air conditioning systems at set point temperatures close to the standard indoor room set point temperature of 26°C as well as the practice of energy conservation measures such as load shedding can reduce electricity consumption and the environmental impacts of buildings.
Conclusions:
Existing building energy codes, utilized in combination with appliance standards, and labeling and information programs can reduce energy consumption, air emissions and energy bills. New policies, for example, policies which encourage building facilities managers to meet a recommended indoor set point temperature to minimize energy consumption for cooling in commercial buildings could be introduced. In the long run, the environmental impacts of buildings will need to be addressed. Incorporation of environmental life cycle assessment into the current building code is proposed.
Recommendations and
Perspectives:
It is difficult to conduct a full and rigorous life cycle assessment of an office building as it consists of many materials and components. This study made an effort to access reliable data as quickly as possible on all the life cycle stages: manufacturing, construction, operation, maintenance and demolition. Nevertheless, there were a number of assumptions made in the study due to the unavailability of adequate data. Further studies with more detailed, reliable and Thailand specific inventories for building materials end of life scenarios are recommended.
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