This document establishes criteria and a methodology for providing accessibility to immovable cultural heritage through interventions arising from conservation, restoration or specific accessibility needs. It is applicable to immovable cultural heritage and its setting. It is not applicable to general management, organizational and other aspects of a functional nature that are not directly related to the conservation, restoration or specific accessibility interventions. This document is intended to be used by heritage owners and managers (both private or public), curators, accessibility professionals, conservation and restoration professionals, architects, engineers, designers, user representatives and builders. Requirements and recommendations related to the design and constructional aspects of an accessible built environment are covered by ISO 21542.