EN ISO 3744:2010

Foreword
Introduction
1 Scope
2 Normative references
3 Terms and definitions
4 Test environment
5 Instrumentation
6 Definition, location, installation, and operation of
   noise source under test
7 Reference box and measurement surface
8 Determination of sound power levels and sound energy levels
9 Measurement uncertainty
10 Information to be recorded
11 Test report
Annex A (normative) - Qualification procedures for the
        acoustic environment
Annex B (normative) - Microphone arrays on a hemispherical
        measurement surface
Annex C (normative) - Microphone arrays on a parallelepiped
        measurement surface
Annex D (informative) - Microphone arrays on a cylindrical
        measurement surface
Annex E (normative) - Calculation of A-weighted sound power
        levels and A-weighted sound energy levels from
        frequency band levels
Annex F (normative) - Alternative microphone array on a
        hemispherical measurement surface for direct
        measurements of A-weighted sound pressure levels
Annex G (normative) - Sound power level and sound energy
        level under reference meteorological conditions
Annex H (informative) - Guidelines on the development of
        information on measurement uncertainty
Bibliography
Annex ZA (informative) - Relationship between this European
         Standard and the Essential Requirements of EU
         Directive 2006/42/EC

ISO 3744:2010 specifies methods for determining the sound power level or sound energy level of a noise source from sound pressure levels measured on a surface enveloping the noise source (machinery or equipment) in an environment that approximates to an acoustic free field near one or more reflecting planes. The sound power level (or, in the case of noise bursts or transient noise emission, the sound energy level) produced by the noise source, in frequency bands or with frequency A-weighting applied, is calculated using those measurements.The methods specified in ISO 3744:2010 are suitable for all types of noise (steady, non-steady, fluctuating, isolated bursts of sound energy, etc.) defined in ISO 12001.ISO 3744:2010 is applicable to all types and sizes of noise source (e.g. stationary or slowly moving plant, installation, machine, component or sub-assembly), provided the conditions for the measurements can be met.The test environments that are applicable for measurements made in accordance with ISO 3744:2010 can be located indoors or outdoors, with one or more sound-reflecting planes present on or near which the noise source under test is mounted. The ideal environment is a completely open space with no bounding or reflecting surfaces other than the reflecting plane(s) (such as that provided by a qualified hemi-anechoic chamber), but procedures are given for applying corrections (within limits that are specified) in the case of environments that are less than ideal.Information is given on the uncertainty of the sound power levels and sound energy levels determined in accordance with ISO 3744:2010, for measurements made in limited bands of frequency and with frequency A-weighting applied. The uncertainty conforms to ISO 12001:1996, accuracy grade 2 (engineering grade).