ISO 3741:2010
Acoustics — Determination of sound power levels and sound energy levels of noise sources using sound pressure — Precision methods for reverberation test rooms
ISO 3741:2010 specifies methods for determining the sound power level or sound energy level of a noise source from sound pressure levels measured in a reverberation test room. 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-third-octave, is calculated using those measurements, including corrections to allow for any differences between the meteorological conditions at the time and place of the test and those corresponding to a reference characteristic impedance. Measurement and calculation procedures are given for both a direct method and a comparison method of determining the sound power level and the sound energy level.
In general, the frequency range of interest includes the one-third-octave bands with mid-band frequencies from 100 Hz to 10 000 Hz. Guidelines for the application of the specified methods over an extended frequency range in respect to lower frequencies are given in an annex. ISO 3741:2010 is not applicable to frequency ranges above the 10 000 Hz one-third-octave band.
The methods specified in ISO 3741:2010 are suitable for all types of noise (steady, non-steady, fluctuating, isolated bursts of sound energy, etc.) defined in ISO 12001.
The noise source under test can be a device, machine, component or sub-assembly. ISO 3741:2010 is applicable to noise sources with a volume not greater than 2 % of the volume of the reverberation test room. For a source with a volume greater than 2 % of the volume of the test room, it is possible that the achievement of results as defined in ISO 12001:1996, accuracy grade 1 (precision grade) is not feasible.
The test rooms that are applicable for measurements made in accordance with ISO 3741:2010 are reverberation test rooms meeting specified requirements.
Information is given on the uncertainty of the sound power levels and sound energy levels determined in accordance with ISO 3741:2010, for measurements made in limited bands of frequency and for A-weighted frequency calculations from them. The uncertainty conforms to ISO 12001:1996, accuracy grade 1 (precision grade).
| Get this standard | Prices exclude GST | |
|---|---|---|
| PDF ( Single user document) |
$361.74 NZD
|
|
| HardCopy |
$406.09 NZD
|
|
| Networkable PDF |
Price varies
|
Scope
General
Types of noise and noise sources
Reverberation test room
Measurement uncertainty
Normative references
Terms and definitions
Reference meteorological conditions
Reverberation test room
General
Volume and shape of test room
Sound absorption of test room
Criteria for background noise
Relative criteria for background noise
General
Relative background noise criteria for frequency band measur
Relative background noise criteria for A-weighted measuremen
Absolute criteria for background noise
Statement of non-conformity with background noise criteria
Atmospheric temperature, humidity and pressure
Instrumentation and measurement equipment
General
Calibration
Definition, location, installation, and operation of noise s
General
Auxiliary equipment
Noise source location
Installation and mounting conditions
Operation of source during test
Measurements in the reverberation test room
General
Initial location of the noise source under test
Microphone positions
Measurement of sound pressure levels
General
Further evaluation in a test room that is not qualified for
General
Determination of standard deviations from preliminary measur
Number of microphone positions to be used
Evaluation of need for additional noise source positions
Measurements to be used for determining sound power levels
Measurement of single event time-integrated sound pressure l
General
Further evaluation in a test room that is not qualified for
General
Measurements to be used for determining sound energy levels
Measurement of sound pressure levels from the reference soun
Location of the reference sound source
Sound pressure levels from the reference sound source
Measurement of reverberation time
Measurement of meteorological conditions
Determination of sound power levels and sound energy levels
Determination of sound power levels
Calculation of measured time-averaged sound pressure levels
Corrections for background noise
Calculation of mean time-averaged sound pressure levels in t
Calculation of sound power levels using the equivalent absor
Calculation of sound power levels using the reference sound
Determination of sound energy levels
Calculation of the mean of the measured single event time-in
Corrections for background noise
Calculation of mean single event time-integrated sound press
Calculation of sound energy levels using the equivalent abso
Calculation of sound energy levels using the reference sound
A-weighted sound power level and sound energy level
Measurement uncertainty
Methodology
Determination of (omc
Determination of (R0
General
Round robin test
Modelling approach for (R0
Typical upper bound values of (R0
Total standard deviation (tot and expanded measurement uncertainty, U
Information to be recorded
General
Noise source under test
Test environment
Instrumentation
Acoustical data
Test report
Previous versions
Keep me up-to-date
Register to receive notifications when updates are made to this standard.
Related Information
Similar Standards
-
AS/NZS 1276.1:1999
Acoustics - Rating of sound insulation in buildings and of building elements - Airborne sound insulation
-
BS 7445-1:2003
Description and measurement of environmental noise, Guide to quantities and procedures
-
BS 7445-2:1991
Description and measurement of environmental noise, Guide to the acquisition of data pertinent to land use
-
BS 7445-3:1991
Description and measurement of environmental noise, Guide to application to noise limits
Scope
General
Types of noise and noise sources
Reverberation test room
Measurement uncertainty
Normative references
Terms and definitions
Reference meteorological conditions
Reverberation test room
General
Volume and shape of test room
Sound absorption of test room
Criteria for background noise
Relative criteria for background noise
General
Relative background noise criteria for frequency band measur
Relative background noise criteria for A-weighted measuremen
Absolute criteria for background noise
Statement of non-conformity with background noise criteria
Atmospheric temperature, humidity and pressure
Instrumentation and measurement equipment
General
Calibration
Definition, location, installation, and operation of noise s
General
Auxiliary equipment
Noise source location
Installation and mounting conditions
Operation of source during test
Measurements in the reverberation test room
General
Initial location of the noise source under test
Microphone positions
Measurement of sound pressure levels
General
Further evaluation in a test room that is not qualified for
General
Determination of standard deviations from preliminary measur
Number of microphone positions to be used
Evaluation of need for additional noise source positions
Measurements to be used for determining sound power levels
Measurement of single event time-integrated sound pressure l
General
Further evaluation in a test room that is not qualified for
General
Measurements to be used for determining sound energy levels
Measurement of sound pressure levels from the reference soun
Location of the reference sound source
Sound pressure levels from the reference sound source
Measurement of reverberation time
Measurement of meteorological conditions
Determination of sound power levels and sound energy levels
Determination of sound power levels
Calculation of measured time-averaged sound pressure levels
Corrections for background noise
Calculation of mean time-averaged sound pressure levels in t
Calculation of sound power levels using the equivalent absor
Calculation of sound power levels using the reference sound
Determination of sound energy levels
Calculation of the mean of the measured single event time-in
Corrections for background noise
Calculation of mean single event time-integrated sound press
Calculation of sound energy levels using the equivalent abso
Calculation of sound energy levels using the reference sound
A-weighted sound power level and sound energy level
Measurement uncertainty
Methodology
Determination of (omc
Determination of (R0
General
Round robin test
Modelling approach for (R0
Typical upper bound values of (R0
Total standard deviation (tot and expanded measurement uncertainty, U
Information to be recorded
General
Noise source under test
Test environment
Instrumentation
Acoustical data
Test report