This International Standard specifies procedures for measuring and reporting the noise emitted by computer and business equipment. It is based on the measurement procedures specified in ISO 3740, ISO 3741, ISO 3742, ISO 3744 and ISO 3745. The basic emission quantity is the A-weighted sound
power level which may be used for comparing equipment of the same type, but from different manufacturers, or for comparing different equipment.
The A-weighted sound power level is supplemented by the A-weighted sound pressure level measured at the operator position(s) or the bystander positions. This sound pressure level is not a measurement of total occupational noise exposure of workers (noise immission).
Two methods for determining the sound power levels are specified in this International Standard in order to avoid undue restriction on existing facilities and experience. The first method is based on reverberant room measurements (see ISO 3741 and ISO 3742); the second is based on measurements in an essentially free field ?ver a reflecting plane (see ISO 3744 and ISO 3745). Either method may be used in accord-ance with this International Standard. They are comparable in accuracy and yield the same A-weighted sound power level within the tolerance range of the methods specified in this International Standard.
SIS SS-ISO 7779:1989 history
1989SIS SS-ISO 7779:1989 Acoustics — Measurement ofairborne noise emitted by computer and business equipment