ISO 21542:2011 Building construction -Accessibility and usability of the built environment
The international ISO 21542 specifies a range of recommendations for many of the elements of construction, assemblies, components and fittings which comprise the built environment. This can be used as a best-practice guide when developing Performance Solutions.
These requirements relate to the constructional aspects of access to buildings, to circulation within buildings, to egress from buildings in the normal course of events and evacuation in the event of an emergency.
ISO 21542:2011 contains provisions with respect to features in the external environment directly concerned with access to a building or group of buildings from the edge of the relevant site boundary or between such groups of buildings within a common site.
You can purchase a copy of ISO 21542 from the International Organization for Standardization.