NBN EN ISO 3741 : 2010

1 Scope
2 Normative references
3 Terms and definitions
4 Measurement uncertainty
5 Acoustic environment
   5.1 General
   5.2 Volume and shape of test room
   5.3 Requirements for absorption of test room
   5.4 Requirements for background noise level
   5.5 Requirements for temperature, humidity and pressure
6 Instrumentation
   6.1 General
   6.2 Calibration
7 Installation and operation of source under test
   7.1 General
   7.2 Source location
   7.3 Source mounting
   7.4 Auxiliary equipment
   7.5 Operation of source during test
8 Sound pressure measurements and sound power determination
   8.1 Initial measurements
   8.2 Additional measurements
   8.3 Determination of average sound pressure level in the test
       room
   8.4 Determination of the sound power level of the sound source
   8.5 Determination of A-weighted sound power level of the source
9 Information to be recorded
   9.1 Noise sources under test
   9.2 Acoustical environment
   9.3 Instrumentation
   9.4 Acoustical data
10 Information to be reported
Annex A (normative) Room qualification procedure for the
        measurement of discrete-frequency components
Annex B (informative) Guidelines for the design of rotating
        diffusing vanes
Annex C (informative) Extension for frequencies below 100 Hz
Annex D (informative) Guidelines for the design of
        reverberation rooms
Annex E (normative) Test room qualification procedure for the
        measurement of broad-band sound
Annex F (normative) Procedure for calculating octave band sound
        power levels and an A-weighted sound power level from
        one-third-octave band sound power levels
Bibliography
Annex ZA (normative) Normative references to international
         publications with their relevant European
         publications

Gives a direct and a comparison method to determine the sound power level that would be produced by a source operating in an environment at standard meterological conditions corresponding to a characteristic impedance of pc = 400 N-s/m3. Specifies test room requirements, source location and general rules for operating conditions. Suitable for steady noise with broad-band, narrow-band and discrete-frequency components. Applies to noise sources with volumes which are preferably not more than 2% of the volumes of the reverberation room which is used for the test.