1.1 General This International Standard specifies a method for determining the emission sound pressure levels of machinery or equipment, at a work station and at other specified positions nearby, in an essentially free field over a reflecting plane. A work station is occupied by an operator and may be located in open space, in the room where the source under test operates, in a cab fixed to the source under test, or in an enclosure remote from the source under test. One or more specified positions may be located in the vicinity of a work station, or in the vicinity of an attended or unattended machine. Such positions are sometimes referred to as bystander positions. Emission sound pressure levels are determined as A-weighted levels. Additionally, levels in frequency bands and C-weighted peak emission sound pressure levels can be determined in accordance with this International Standard, if required. NOTE 1 The contents of the ISO 11200 series (ISO 11201[16] to ISO 11205[19]) are summarized in ISO 11200[15]. With the method specified in this International Standard, results of accuracy grade 1 (precision grade) or accuracy grade 2 (engineering grade) are obtained. Corrections are applied for background noise, but not for the acoustic environment. Instructions are given for the mounting and operation of the source under test and for the choice of microphone positions for the work station and for other specified positions. One purpose of the measurements is to permit comparison of the performance of different units of a given family of machines, under defined environmental conditions and standardized mounting and operating conditions. NOTE 2 The data obtained can also be used for the declaration and verification of emission sound pressure levels as specified in ISO 4871[8].