Cradle-to-gate life cycle assessment of energy and carbon of a residential building in Sri Lanka

Abstract

The growing concerns over the environment have led to increasing demand for environmentally-friendly buildings. So far, only a few studies on environmental impacts of buildings have been conducted in the context of Sri Lanka. Reliable data sources that match the specific conditions of the country are limited. Using the life cycle assessment (LCA) methodology, this paper presents a cradle-to-gate energy and carbon emission study of a multi-storey residential building in a Sri Lankan university. The total embodied energy and carbon of the building are 3.84 GJm-2 and 229.34 kgCO 2 m-2 , respectively, which are comparable with results of similar studies found in literature. Reinforced concrete, the main structural material, contributed to 61 % of total embodied energy and 71 % of total embodied carbon of the building. Despite the relatively low material quantity used, aluminium, ceramic tiles and paint shared 18.67 % of total embodied energy. In order to achieve low-energy and low-carbon buildings in Sri Lanka, several strategies were identified; suitable construction practices and building designs to reduce quantities of mass materials, use of alternative materials with low energy and carbon intensities, material recycling and reuse, use of clean and renewable energy for production processes and popularising the concept of eco-labels for building materials. The reduction of embodied energy and carbon is expected to lighten the environmental footprint of buildings.

Life Cycle Assessment of Geotechnical Works in Building Construction: A Review and Recommendations

“…Few of the reviewed articles had achieved a compromised balance between coverage of the various stages of the building's life cycle and the level of detail in geotechnical construction works. In the six articles including building foundations, either as part of the whole building life cycle analysis [53] or the construction stage [54][55][56][57][58], only limited information on building foundations was presented. In fact, most of them presented aggregated results for the total mass of foundation materials and their relative contribution to the overall impact of the system studied.…”

“…A total of four types of system boundaries were applied in the twelve articles. Specifically, eight articles employed the cradle-to-site boundary [54][55][56]58,[60][61][62][63], two the cradle-to-gate boundary [57,59], one the cradle-to-grave boundary [53], and one the gate-to-site boundary [64]. However, the criteria used to define system boundaries were not clarified in all the articles.…”

“…However, the criteria used to define system boundaries were not clarified in all the articles. Taking the two articles employing the cradle-to-gate boundary as an example [57,59], neither explained why the transport vehicles and on-site use of machines were excluded from the study.…”

“…A variety of functional units were defined in the reviewed articles (Table 1). Four different functional units were defined in the six articles [53][54][55][56][57][58] on the building life cycle or the product/construction stages. Six different functional units were used in the six articles [59][60][61][62][63][64] focusing on building foundations.…”

“…In the article on CSF [61], for instance, the authors defined the functional unit as "an isolated shallow CSF that can withstand a 0.4 × 0.4 m column with a dead load of 400 kN and an imposed load of 150 kN, built on a silty soil with a bearing pressure of 150 kN/m 2 , without the presence of a water table, seismicity, or chemical action, and designed for a service life of 50 years". Furthermore, most of the articles reviewed lacked clear explanations of the functional units, making it difficult to distinguish differences between similar functional units, such as: (i) "total construction area" [64] and "total built-up area" [53], and (ii) "gross floor area" [54,57,58], "useful floor area" [55] and "building floor area" [59]. It is therefore difficult to compare the results from these LCA studies in a reliable way.…”