This International Standard provides brief summaries of the basic International Standards for determining emission sound pressure levels from all types of machinery and equipment, at work stations and at other specified positions, and gives guidance on the process of selection of which is appropriate to any particular type. The guidance given applies only to airborne sound, and is for use in the preparation of noise test codes, and also for use in noise testing where no noise test code exists.It is important that specific noise test codes for various types of machinery and equipment be established and used in accordance with the requirements of these basic International Standards. Such standardized noise test codes will give detailed requirements on mounting and operating conditions for the particular family to which the machine under test belongs, as well as the location of the work station(s) and other specified positions as prescribed in these International Standards. The data so obtained may also be used for the declaration and verificaion of emission sound pressure levels as specified in ISO 4871.NOTE 1 At any given position in relation to a particular machine, and for given mounting and operating conditions, the emission sound pressure levels determined by any of the methods given in ISO 11201 to ISO 11204 will in general be lower than the directly measured sound pressure levels for the same machine in the typical workroom where it is used. This is due to reverberation and the contributions of other machines. A method of calculating the sound pressure levels in the vicinity of a machine operating alone in a workroom is given in ISO 11690-3. Commonly observed differences are 1 dB to 5 dB, but in extreme cases the difference may be even greater.