EN ISO 3747:2010

Foreword
Introduction
1 Scope
2 Normative references
3 Terms and definitions
4 Test environment
5 Instrumentation and measurement equipment
6 Location, installation and operation of noise source under
   test
7 Measurement procedure
8 Calculation of sound power levels and sound energy levels
9 Measurement uncertainty
10 Information to be recorded
11 Test report
Annex A (normative) - Evaluation of the excess of sound pressure
        level at a given distance
Annex B (informative) - Recommendations for the location of the
        reference sound source and the microphones, if only one
        position is used for the reference sound source
Annex C (normative) - Sound power level and sound energy level
        under reference meteorological conditions
Annex D (normative) - Calculation of A-weighted sound power
        levels and A-weighted sound energy levels from
        octave-band levels
Annex E (informative) - Guidance 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 3747:2010 specifies a method for determining the sound power level or sound energy level of a noise source by comparing measured sound pressure levels emitted by a noise source (machinery or equipment) mounted in situ in a reverberant environment, with those from a calibrated reference sound source. 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 of width one octave, is calculated using those measurements. The sound power level or sound energy level with frequency A-weighting applied is calculated using the octave-band levels.The method specified in ISO 3747:2010 is suitable for all types of noise (steady, non-steady, fluctuating, isolated bursts of sound energy, etc.) defined in ISO 12001. The method is primarily applicable to sources which emit broad-band noise. It can, however, also be used for sources which emit narrow-band noise or discrete tones, although there is a possiblity that the measurement reproducibility is then degraded.The noise source under test can be a device, machine, component or sub-assembly, especially one which is non-movable.The test environment that is applicable for measurements made in accordance with ISO 3747:2010 is a room where the sound pressure level at the microphone positions depends mainly on reflections from the room surfaces. In measurements of ISO 12001:1996, accuracy grade 2 (engineering grade), background noise in the test environment is low compared to that of the noise source or reference sound source.Information is given on the uncertainty of the sound power levels and sound energy levels determined in accordance with ISO 3747:2010, for measurements made in octave bands and for A-weighted frequency calculations performed on them. The reproducibility conforms with that of either ISO 12001:1996, accuracy grade 2 (engineering grade) or ISO 12001:1996, accuracy grade 3 (survey grade), depending on the extent to which the requirements concerning the test environment are met.