Abstract
Solar radiation in the urban built environment is a key aspect to assure luminous and thermal comfort. Solar access is regulated by urban restrictions for buildings, which seek to ensure a certain level of exposure to the sun in terms of time (hours), energy (Joule), or a mixture of them. The main goal of this work is to present an urban planning tool called Section Lines, which allows to define the maximum height of the buildings, in such a way that a minimum of sun exposure hours are assured on the north, east and west facades of the buildings during some period of time during the year. Compared to the current standard of solar access in Chile "rasante", the application of Section Lines allows to increase up to ten times the solar radiation on the north facades during the winter season.