Building Performance Score Model for Assessing The Sustainable Performance In Life Cycle of Building

Abstract

The construction industry is one of the major sectors contributing to the economic development of our country. This industry also acts as a significant source of pollution towards environment and the impact of these are very severe. To overcome this impact, the concept of sustainability in the construction sector has emerged. This concept helps maintain proper balance in environment and ensure that the natural habitats are not disturbed. In the coming years, vital importance is given to the concept of sustainability and various rating tools to measure the performance of green buildings. However, with critical reviews on the current tools, they are criticized as being ineffective and inefficient in addressing the building performance issues, as most of them only focus on assessing building performance on environmental criteria and the assessment does not take into consideration economic and social analysis. Sustainability is like a three-legged stool, with each leg representing areas of environment, economy and society. Any leg missing from the ‘sustainability stool’ will cause instability because the three components are intricately linked together. In addition, most current tools have not considered all the building phases in their assessment. As economic, social and environmental impacts associated with project development will vary at different stages throughout its life cycle, sustainable performance should be assessed and incorporated into the building process. In the Indian context, the existing building assessment tools emphasise more on environmental impact rather than economical and social impacts. To address this issue, the Building Performance Score (BPS) model is developed pertaining to building sustainability based on triple bottom line priorities, consisting of environmental, economical, and social concepts. Therefore the aim of this study is to identify the assessment indicators based on triple bottom line and develop a conceptual model to assess the buildings for their sustainability performance. This model includes 44 indicators that play a significant role in the sustainability assessment of construction buildings. Different phases in the life cycle of building are identified and corresponding indicators in each stage that influence environmental, economic and social aspects are also identified. Among the total indicators, there are 19 environmental indicators, 12 economic indicators, and 13 social indicators. A questionnaire survey and semi-structured interviews were conducted to collect the data. Both quantitative and qualitative methods are used in this study. The questionnaire survey was conducted online, and 123 people responded positively. The survey was conducted to deduce the building stage divisions and the pertaining indicators. The outcome of this study specifies that various indicators such as the topographical and climate change, health and safety of the construction workers, project management consultancy, risk management, security measures, and solid waste management forms a chief source of a sustainable building and these indicators are not being assessed in the existing assessment tools. Moreover, these indicators are also required to be assessed and included in the evaluation process while assessing the performance of the building. Also, consideration of environmental, economic and social factors is equally important in construction industry. Formulation of BPS model is based on the identified indicators obtained from questionnaire survey and literature review. Analytic Hierarchy Process (AHP) is used to identify the importance of assessment indicators. Further, various assessment methods such as Life Cycle Assessment (LCA), Life Cycle Costing (LCC) and Value Score (VS) are also used for evaluation of indicators. In the present study, three different certified green buildings were considered and performance assessment of the building was carried out using the BPS model. The BPS for the three case studies is 7.24, 4.47 and 7.92 respectively. Their corresponding LEED certified scores are 54 (Platinum), 41 (Gold) and 57 (Platinum). Moreover, the Building Performance Score (BPS) indicates the sustainable performance of the building. The assessment is carried out at every stage which gives a proper understanding to the stakeholders regarding the impact of every stage. This will also help in undertaking required changes in the design in order to be more sustainable before the actual construction of the building begins. The characteristic of BPS model of considering all the three aspects for assessment, total cost incurred and impact on local society is an added advantage for the stakeholders to assess the project. From the study, it is evident that considering economic and social aspects along with environmental aspects for assessment of buildings is necessary which is missing in the existing assessment tools. With the incorporation of various indicators for assessment, a better performance assessment result for the building can be obtained. Hence this BPS model proves to be an enhanced approach in building performance assessment throughout the complete life cycle of the building. The benefits and outcome of BPS model are also discussed in this research. This research supports a sustainable building assessment tools which is different from other approaches and maintains that it is essential to apply sustainable assessment at various phases of building development cycle. Other assessment tools provide environmental performance of the project, whereas BPS provides sustainable performance that considers the impacts of sustainability aspects at every phase of the building development cycle. The BPS model offers a detailed vision regarding the building performance assessment process and will surely aid the achievement of construction practices that are sustainable for the Indian construction industry. Hence, this model can be used for assessing the sustainable performance of any building in India and other developing countries by incorporating respective regional criterion.