Daylighting and Urban Form: An Urban Fabric of Light

This article attempts to answer the question, "What would the form of the city be like if we were to take seriously the provision of daylight to all buildings?" Previous work by this author reviewed existing daylight planning tools and found that they do not assure a predictable level of daylight. Previous work also identified an empirical relationship between daylight levels inside buildings and the street canyon ratios--the Daylight Access Rule--as an objective basis for establishing development guidelines. This study identifies the important parameters available to designers and regulators that are necessary for urban daylighting. The results of the new Daylight Access Rule, along with Atrium Building type studies, are used to establish urban patterns of Atrium Blocks and Daylight Envelopes that support daylighting as an urban design strategy. Beyond defining the patterns of building massing, such that one building will not unduly block the access of another building to light from the sky, urban form can be generated from a consideration of daylit building forms used as increments for determining block sizes. An example application to downtown Chattanooga, Tennessee, is explored to evaluate existing development patters and to propose alternatives to better support daylighting.