Green building certification systems: An assessment of the city of Izmir

This study examines the sustainability performance of LEED and BREEAM-certified green buildings in Izmir, province of Türkiye, in terms of certification levels, assessment categories, building types and the environmental strategies implemented. Guided by a conceptual framework based on sustainability, sustainability in architecture, urban sustainability, the green building approach and international certification systems, the research aims to provide a comparative assessment at a local-scale. A qualitative research approach was adopted in the study; document analysis was used as the data collection technique. Data obtained from ÇEDBİK, USGBC, BREEAM and relevant project sources were classified according to certification type, certification level, total score, credit categories, building function and sustainability strategies; and interpreted using descriptive statistics and comparative content analysis. In this respect, the study distinguishes itself from research focusing on a single building type or a single certification category by developing a multi-typology evaluation framework based on the example of Izmir province. The findings show that there are 32 LEED-certified projects in Izmir and four BREEAM certification records associated with three separate buildings or projects. It was determined that performance in LEED-certified buildings is concentrated in the categories of energy and atmosphere, water efficiency, indoor environmental quality, location and transport, and sustainable sites; however, the materials and resources category is under-represented. BREEAM projects, on the other hand, are characterised by the operational performance of existing buildings, environmental management, energy and water conservation, waste control, user comfort and safety measures. Furthermore, it has been observed that sustainability priorities vary according to building function; different strategies are prominent in office, industrial, commercial, residential and transport buildings. The study reveals that green building practices in Izmir are spreading across different building functions; however, the publicly available records examined are insufficient to directly assess the spatial and socio-economic dimensions of this spread. Based on the findings, it is recommended that the strong practices observed in energy and water efficiency be maintained; while sustainability strategies relating to materials and resource management, the operational performance of existing buildings, and building functionality should be developed through local policies and incentives.