This International Standard specifies procedures for measuring
and reporting the noise emission of information technology and
NOTE 1 This International Standard is considered part of a noise
test code (see 3.1.2) for this type of equipment, and is based on
basic noise emission standards (see 3.1.1) ISO 3741, ISO 3744, ISO
3745 and ISO 11201.
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.
Three basic noise emission standards for determination of the
sound power levels are specified in this International Standard in
order to avoid undue restriction on existing facilities and
experience. ISO 3741 specifies comparison measurements in a
reverberation test room; ISO 3744 and ISO 3745 specify measurements
in an essentially free field over a reflecting plane. Any one of
these three basic noise emission standards can be selected and used
exclusively in accordance with this International Standard when
determining sound power levels of a machine.
The A-weighted sound power level is supplemented by the
A-weighted emission sound pressure level determined at the operator
position(s) or the bystander positions, based on basic noise
emission standard ISO 11201. This sound pressure level is not a
worker's immission rating level, but it can assist in identifying
any potential problems that could cause annoyance, activity
interference, or hearing damage to operators and bystanders.
Methods for determination of whether the noise emission includes
prominent discrete tones or is impulsive in character are specified
in Annexes D and E, respectively.
This International Standard is suitable for type tests and
provides methods for manufacturers and testing laboratories to
obtain comparable results.
The methods specified in this International Standard allow the
determination of noise emission levels for a functional unit (see
3.1.4) tested individually.
The procedures apply to equipment which emits broad-band noise,
narrow-band noise and noise which contains discrete-frequency
components, or impulsive noise.
The sound power and emission sound pressure levels obtained can
serve noise emission declaration and comparison purposes (see ISO
NOTE 2 The sound power and emission sound pressure levels
obtained are not to be considered as installation noise immission
levels; however, they can be used for installation planning (see
If sound power levels obtained are determined for a number of
functional units of the same production series, they can be used to
determine a statistical value for that production series (see ISO
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