This document specifies a range of requirements and recommendations for the elements of construction, building assemblies, components, fittings and products that relate to the design and constructional aspects of usability and accessibility of buildings, i.e. access to buildings, circulation within buildings, egress from buildings during normal conditions, and evacuation in the event of a fire. This document also applies to the common spaces in multi-unit residential buildings. Recommendations regarding residential units are given in Annex A. This document also contains provisions with respect to outdoor features directly concerned with access to a building or a group of buildings from a relevant site boundary, or between such a group of buildings within a common site. This document does not deal with elements of the external environment, such as public open spaces, whose function is self-contained and unrelated to the use of a specific building. This document is applicable to new buildings and new work in existing buildings. This document introduces the concept of ‘exceptional considerations for existing buildings’ for situations where it is exceptionally difficult to meet the requirements specified and, thus, impossible to provide full accessibility. By means of ‘exceptional considerations for existing buildings’, an acceptable, though restricted, level of accessibility is specified. An exceptional consideration for existing buildings is not to be applied in other situations or invoked in an unjustified manner, or as an excuse for not achieving a higher level of accessibility, where this is economically and/or technically feasible. The dimensions stated in this document, relevant to the use of wheelchairs, are related to the footprint of commonly used wheelchair sizes and users as specified in ISO 7176-5 and ISO/TR 13570-2, 800 mm wide and 1 300 mm long. This document is primarily written for adults with disabilities, but it includes some recommendations on specific accessibility needs of children.