1. Introduction Human activities which requires material and energy to develop have irreversible effects on ecological systems and environment such as climate change, the depletion of natural resources, waste generation, pollution etc. Most of these impacts have hazardous consequences for human health and survival and most of these effects have long-termed results. (Crawford, 2011) In Brundtland Report which is published in 1987, Sustainable development is defined “the development that meets the needs of the present without compromising the ability of future generations to meet their own needs.” (Paulsen, 2001) A subset of sustainable development which has been evolving worldwide for almost 25 years, the role of built environment is very important. (Kibert, 2012) The construction is a highly effective industry to improve social, economic and environmentally sustainable development with its globally emerging and a highly active characteristic feature in both developed and developing countries. (Ortiz et al., 2009) İt is required natural resources from the Earth to construct human- made structures such as building, bridges, roads. (Crawford, 2011) According to the Word Watch Institute, building construction and infrastructure consumes materials, which extracted from lithosphere between 45% and 60% ranges. (Cuchi 2005) (De Joanna et al., 2012) Buildings also require resources (energy, water ets.) to supply comfort conditions, such as heating, cooling and lighting. For this reason, the built environment causes a wide range of environmental impacts such as global warming, waste production, depletion of natural resources, pollution of air, land and water and also human health impacts etc. during construction, operation or use and eventual demolition phases of buildings. (Crawford, 2011) From past few years, environmental impacts caused by buildings such as global warming are increasing rapidly and according to researchers the changes in global climate will continue with time (Hulme et al., 2002; International Panel on Climate Change, 2011a). (Sharma et. al., 2012) Buildings are responsible of 40 % percent of greenhouse gas emissions which results global warming the human race’s greatest environmental impact ever challenged on the Earth. (OECD 2003). It is estimated that, operation of buildings accounts 40% percent of total global energy demand and resource consumption on the earth. (Crawford, 2011) Environmental impacts of buildings is expected to increase to 60% by the year 2030 due to the rapidly increasing population of the world (Sayal, Hastak, Mullens, & Sweaney, 2006) (Sharma et. al., 2012) The building industry has an important role to reach a sustainable society within a reasonable period of time with also its long service time. (Erlandsson, M., & Borg, 2003). In This review initially the Life Cycle Assessment (LCA) method which is an applicable tool on all system levels in the building sector, (Erlandsson, M., & Borg, 2003) will be denied and the end of life option of structural steel will be evaluated in environmental burden. 2. Brief History of Life Cycle Assessment (LCA) Life Cycle Assessment (LCA) is a tool for evaluating the environmental aspects of products at all stages in their life cycle. LCA is defined as the "compilation and evaluation of the inputs, outputs and potential environmental impacts of a product system throughout its life cycle" in ISO 14040 Standard. A products life cycle includes all processes from raw material acquisition through material production and manufacturing to use and final disposal including recovery options. Any transportation in these phases is also accounted Havva Aksel 1 , Özlem Eren 2 1 Res. Assist. Havva Aksel, Mimar Sinan Fine Arts University, Meclis-i Mebusan Caddesi No: 24 Fındıklı, 34427 İstanbul, Turkey 2 Assoc. Prof. Dr. Özlem Eren, Mimar Sinan Fine Arts University, Meclis-i Mebusan Caddesi No: 24 Fındıklı, 34427 İstanbul, Turkey Life Cycle Assessment (LCA) in Buildings and Environmental Assessment of Structural Steel’s End of Life Options Buildings interact with the environment directly or indirectly at their life cycle. There occur various environmental impacts in construction, operation and maintenance of buildings. As a result of these impacts natural balance and human health are badly influenced. In concern with, it is important to reveal environmental impacts of buildings to make an environmental decision. LCA is a method to assess environmental impact of a products at their whole life cycle or one of the life cycle stages. LCA is an important decision making support tool applicable for buildings, building materials and components including construction, operation and maintenance stages. The aim of this review is to attract attention to sustainability and environmentally friendly building material selection on using the example of steel structural building components having a high recovery potentiality. The Steel is a sustainable building material with end of life options just as recycling and reuse. Recycling is a process using a material as an input to produce a new material at its end of life cycle. Reuse is an application of disassembly to use component or material without melting This study also reveals the importance of using. recyclable and reusable material in construction sector to reduce environmental impacts. Keywords: Sustainability; LCA; Building Life Cycle; Steel; Reuse; Recycle Proceedings of the 4 TH INTERNATIONAL CONFERENCE ADVANCED CONSTRUCTION 9 – 10 October, 2014, Kaunas, Lithuania Kaunas University of Technology, Faculty of Civil Engineering and Architecture