People expect good natural lighting in their homes and in a wide range of non-domestic buildings. Daylight makes an interior look more attractive and interesting as well as providing light to work or read by. Access to skylight and sunlight helps to make a building energy-efficient; effective daylighting will reduce the need for electric light, while winter solar gain can meet some of the heating requirements. The quality and quantity of natural light in an interior depend on two main factors. The design of the interior environment is important: the size and position of windows, the depth and shape or rooms, the colours of internal surfaces. But the design of the external environment also plays a major role: whether obstructing buildings are so tall that they make adequate daylighting impossible, or whether they block sunlight for much of the year. This guide gives advice on site layout planning to achieve good sunlighting and daylighting, within buildings and in the open spaces between them. It is intended to be used in conjunction with the interior daylight recommendations in the British Standard BS 8206: Part 2 and the "Applications Manual: window design" of the Chartered Institution of Building Services Engineers (CIBSE). It complements them by providing advice on the planning of the external environment. If these guidelines on site layout are followed, along with the detailed window design guidance in the British Standard and CIBSE manual, there is the potential to achieve good daylighting in new buildings, to retain it in existing buildings nearby, and to protect the daylighting of adjoining land for future development. Other sections give guidance on passive solar site layout, on the sunlighting of gardens and amenity areas, and briefly review issues like privacy, enclosure, microclimate, road layout and security. The appendices contain methods to quantify access to sunlight and daylight within a layout. While this guide supersedes the 1971 Department of the Environment document "Sunlight and Daylight" which is now withdrawn, the main aim is the same - to help to ensure good conditions in the local environment, considered broadly, with enough sunlight and daylight on or between buildings for good interior and exterior conditions. The guide is intended for building designers and their clients, consultants and planning officials. The advice given here is not mandatory and this document should not be seen as an instrument of planning policy. Its aim is to help rather than constrain the designer. Although it gives numerical guidelines, these should be interpreted flexibly because natural lighting is only one of many factors in site layout design (see Section 5) In special circumstances the developer or planning authority may wish to use different target values. For example, in a historic city centre a higher degree of obstruction may be unavoidable if new developments are to match the height and proportions of existing buildings. Alternatively, with a building where natural light and solar gain are of special importance, less obstruction and more sunlight and daylight may be deemed necessary. The calculation methods in Appendices A, B, and G are entirely flexible in this respect. Appendix F gives advice on how to develop a consistent set of target values for skylight in such circumstances; and Appendix C shows how to relate these to interior daylighting requirements.

Table of Contents

Part 1 How to use this guide: introduction; light from the sky - new development, existing buildings, adjoining development land; sunlighting - new development, existing buildings; gardens and open spaces; passive solar design; other issues - introduction, view, privacy, security, access, enclosure, microclimate, solar dazzle. Appendix A Indicators to calculate access to skylight, sunlight and solar radiation: A1 general - use of transparent direction finder and use of a plan drawn to a specific scale; A2 use of the skylight indicator; A3 use of the sunlight availability indicators; A4 use of the sunpath indicators; A5 use of the solar gain indicators. Appendix B A Waldram diagram to calculate vertical sky component. Appendix C Interior daylighting recommendations. Appendix D Plotting the no-sky line. Appendix E Rights to light. Appendix F Setting alternative target values for skylight access. Appendix G Calculation of sun on the ground. Appendix H Definitions.