Climatic Envelope as an Urban Planning Tool to Configure Urban Fabric of Guwahati City to Support Daylight and Natural Ventilation

Over the last decade, as a result of rapid urban growth and increasing human population, Guwahati city is witnessing multilayered transformation owing to socio-economic, geo-political and technological issues. This constant increase of built form is resulting haphazard urban growth pattern in down town city areas sacrificing the access to daylight and solar radiation inside residential buildings. Even though the development pattern of Guwahati is controlled by established GMDA building bye-laws; these building regulations and guidelines are unable to control the organic growth of the city since there is no climate-sensitive approach available in the existing GMDA bye-laws. This paper aims to discuss the likelihood of constructing a composite climatic envelope by using daylight spacing angle and solar elevation angle techniques within the residential zone of Guwahati city. This paper also analyses how climatic envelope technique helps to establish an efficient height-to-width (H/W) ratio in spatial arrangement of residential neighbourhood and ensures a higher levels of daylight factor (DF), permits solar access to the neighboring buildings and also enables better ventilation rate inside every rooms of residential buildings. This paper analyses further to discuss about the performance of natural ventilation inside building envelope and reviews the common energy code of openable window to floor area (WFRop) ratio in urban residential buildings. During this study, an existing urban spatial arrangement of residential neighbourhood under GMDA jurisdiction is studied, discussed and analysed. Results of this study, plotting H/W ratio against average daylight factor and ventilation rate can be used as a preliminary urban design tool to configure the urban fabric especially within the residential zone of GMDA area.