This document specifies a range of requirements and recommendations for the elements of construction, building assemblies, components, fittings and products which 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 contains provisions with respect to outdoor features directly concerned with access to a building or 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 those 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 applies to the common spaces in multi-occupation residential buildings. This document is applicable to both new and existing buildings. This document introduces the concept of ‘exceptional considerations’ for those situations making it exceptionally difficult to meet the requirements specified and, thus, making it impossible to provide full accessibility. Such situations can result from economic or technical reasons. By means of ‘exceptional considerations’ an acceptable – though restricted and not ideal yet acceptable – level of accessibility, is specified. It is understood that an exceptional consideration 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. The footprint for a wheelchair within this document is based on ISO 7176-5 and ISO/TR 13570-2 and is 800 mm wide and 1 300 mm long. For larger wheelchairs and scooters, their product dimensions need to be explicitly stated to accommodate them in the space in question. This document is primarily written for adults with disabilities, but it includes some recommendations concerning the specific accessibility needs of children.