This International Standard deals with the performance of enclosures and cabins designed for noise control. It outlines the acoustical and operational requirements which are to be agreed upon between the supplier or manufacturer and the user of such enclosures and cabins. This International Standard is applicable to two types of acoustic enclosures and cabins, as follows. a) Cabins for noise protection of operators: free-standing cabins and cabins attached to machines (e.g. vehicles, cranes). b) Free-standing enclosures covering or housing machines: enclosures with a fraction of acoustically untreated open area of less than 10 % of the total surface are the main subject of this International Standard. In this International Standard, emphasis is put on lightweight constructions. However, thick, massive structures as, for example, brick walls, are not excluded. Enclosures and cabins with more than 10 % open and untreated area belong to the category of partial enclosures. They are not the subject of this International Standard. A third type of enclosure, integrated enclosures which form a part of the machine and are firmly attached to it, is not the subject of this International Standard.