This part of ISO 230 specifies methods for testing the noise of stationary floor-mounted machine tools and related
auxiliary equipment directly on the shop floor. The purpose of the measurements is to obtain noise-emission data
for machine tools.
The data obtained may be used for the purpose of declaration and verification of airborne noise emission from
machine tools as specified in ISO 4871, and also for the comparison of the performance of different units of a given
family of machine tools or equipment, under defined environmental conditions and standardized mounting and
For the purposes of this part of ISO 230, "auxiliary equipment" means hydraulic power packs, chip conveyors,
coolant-oil mist extractors, heat exchangers, refrigerators, etc. Noise emitted by centrally operated auxiliary
equipment, connected to several machine tools, shall be considered as background noise.
General instructions are given for the installation and operation of the machine under test and for the choice of
microphone positions for the work station and for other specified positions. More detailed instructions can be found
in specific noise-test standards for individual types of machine tools.
Clause 11 specifies a method for measuring the emission sound pressure levels at work stations and at other
specified positions in the vicinity of a machine tool. This method follows the methods specified in ISO 11202 and
Clause 12 specifies a method for measuring the sound pressure levels on a measurement surface enveloping the
machine tool and for calculating the sound power level produced by the machine tool. This method follows the
methods specified in ISO 3744 and ISO 3746.
The determination of the sound power level on the basis of the intensity method (ISO 9614 and ISO 9614-2) is not
dealt with in this part of ISO 230.
1.2 Types of noise and noise sources
The methods specified in this part of ISO 230 are suitable for all types of noise emitted by machine tools.
This part of ISO 230 is applicable to machine tools of any type and size, including devices, components and subassemblies.
NOTE Measurements according to this part of ISO 230 may be impracticable for very tall or very long machine tools, such as transfer lines.
1.3 Test environment
The test environment that is applicable for measurements made in accordance with this part of ISO 230 is generally
located indoors, with one or more reflecting planes present, meeting specified requirements, as described in
clauses 11 and 12, respectively in 11.4.2 and in clause 12.3.2.
1.4 Accuracy grades
Individual values of emission sound pressure levels at a fixed position and of the sound power level of a machine
tool determined in accordance with the procedures given in this part of ISO 230 are likely to differ from the true
values by an amount within the range of the respective measurement uncertainties. The uncertainties in
measurements of emission sound pressure levels and in determinations of the sound power level arise from
several factors which affect the results, some associated with environmental conditions at the test site and others
with experimental techniques. This part of ISO 230 deals with methods to determine the emission sound pressure
levels and the emission sound power level, where the results meet grade 2 accuracy (engineering method) and
grade 3 accuracy (survey method). Because of its higher accuracy, grade 2 should be achieved whenever possible.
Specific information on measurement uncertainties is given in clause 7.
Although grade 2 accuracy (engineering) is preferred, grade 3 accuracy (survey) is acceptable for noise declaration
and most other purposes. In this part of ISO 230, only the determination of grade 3 is described completely. For
grade 2, ISO 3744 and ISO 11204 shall also be used.