Climate Responsive Building Guidelines
Addis Ababa is the capital city of Ethiopia, first founded as a town in 1886. The city is located 9.1° North of Equator at an altitude of approximately 2400 m above see level. Gaps are observed between the actual climatic and environmental context of the city and current codes and regulations. The goal of this study is to come up with recommendations to improve existing regulations as well as present general building guidelines in two major scales: Outdoor and Indoor spaces. Five major topics are
Addis Ababa is characterized with a mild weather all through the year with a yearly mean average outside temperature of 16 °C and high solar radiation with an annual horizontal insolation of 2034 kWh/m2/a. Two major climatic conditions are observed all through the year during wet and dry seasons. Due to increased precipitation and cloud cover, wet season is depicted with relatively lower direct solar radiation and less diurnal fluctuations of temperature.
Building codes, standards as well as regulations, both in urban and building level, play a great role in the creation of built as well as open spaces in a city. Such guidelines used for the city of Addis Ababa lack certain crucial climatic considerations. Some of the references claimed to be used date back two and three decades, while some others are from hot climates. Given the climatic environment of Addis Ababa, passive strategies are not sufficiently stressed. Furthermore, provisions for indoor/outdoor thermal comfort, sustainable water utilization and energy consumption of buildings are not exhaustively presented.
In Addis Ababa where outdoor illuminance go as high as 100,000 lux while diffused outdoor illuminance go as high as 60,000 lux, there is huge potential for natural daylighting. Hence it shall be emphasized in current codes and standards. Immediate surrounding massing, building foot print layout, and facade design affect provision of natural daylighting for building spaces. Guidelines concerning glare and minimum spatial illumination requirements shall be emphatically discussed for natural daylighting in contrary to the fact that more focus is donned on artificial lighting in existing standards. Power demand requirements for artificial lighting shall strictly recommend lighting fixtures with good efficiency, hence with less power consumption.
Outdoor air temperature and humidity in Addis Ababa are in a comfortable range providing great potential for natural ventilation during daytime all through the year. It is conducive to provide night flushing during relatively hot times of the year. East and West openings have greater potential for good natural ventilation than North and South openings. Nevertheless, in the Ethiopian Code of Standards,opening part of window is specified not to be less than 1/12th of floor area and minimum fresh air supply of 7 ACH regardless of orientation and context. Such requirements shall be further investigated and presented with greater clarity.
Requirements of thermal comfort are not discussed in current provisions for naturally ventilated spaces. Various combinations of window to wall ratio, kind of glazing, type of shading and size of thermal mass are investigated to come up with guidelines to design building envelope that passively create highly comfortable indoor spaces.
Mentors: Jan Mehnert, Tobias Fiedler
Alpha Arsano – Ethiopia
Alpha completed her Bachelor of Science in Architecture at Ethiopian Institute of Architecture, Building Construction and City Development in 2013. Following the Transsolar Academy in 2014, she worked at Allmann Sattler Wappner Architects in Munich. Currently, as a SMArchS degree candidate in Building Technology, Alpha is research assistant in the Sustainable Design Lab research group at MIT .