ISO 9836:2011 deals with the definition and calculation of surface area and volume indicators.In defining area measurement, ISO 9836:2011 uses three measurement concepts: the intra-muros and extra-muros concept used in many parts of the world; the wall centre method of measurement used in many parts of the world; variations on these methods to comply with certain national laws, or for particular types of buildings.The surface area and volume indicators defined in ISO 9836:2011 are intended for practical use, as a basis for measuring various aspects of the performance of buildings or as a planning aid. In other words, they should enable judgement to be made on functional, technical and economic aspects of buildings.ISO 9836:2011 is intended to be used when establishing:specifications for the geometric performance of a building and its spaces (e.g. in design, purchasing procedures, etc., or in building regulations where appropriate);technical documentation relating to the performance of whole buildings prepared by designers, contractors and manufacturers;the amount of floor area that will not be effectively available for the placement of an individual's workplace, furniture, equipment, or for circulation;evaluation, comparison or control of the properties of a building which are connected to its geometric performance.