This part of ISO 21931 provides a general framework for improving the quality and comparability of methods for assessing the environmental performance of buildings and their related external works. It identifies and describes issues to be taken into account in the development and use of methods of assessment of the environmental performance for new or existing buildings related to their design, construction, operation, maintenance and refurbishment, and in the deconstruction stages. The object of assessment in this part of ISO 21931 is the building and the external works within its site (curtilage). This part of ISO 21931 is intended to be used in conjunction with, and following the principles set out in the “ISO 14020 family of International Standards”, which includes ISO 14020, ISO 14021, ISO 14024 and ISO 14025, as well as ISO 14040 and ISO 15392. Where deviation occurs, this part of ISO 21931 takes precedence. This part of ISO 21931 deals only with methods of assessment of environmental performance and excludes methods of assessment of social and economic performance, which are also part of sustainability and sustainable development. NOTE 1 It is recognized that environmental performance is only one of a number of significant factors in a building's overall performance. NOTE 2 In many cases, methods of assessment of the environmental performance of buildings include consideration of social aspects related to the indoor and local outdoor environment (see Annex A).