NF EN ISO 3741

NF EN ISO 3741

February 2012
Standard Current

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).

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Main informations

Collections

National standards and national normative documents

Publication date

February 2012

Number of pages

73 p.

Reference

NF EN ISO 3741

ICS Codes

17.140.01   Acoustic measurements and noise abatement in general

Classification index

S31-022

Print number

1 - 13/01/2012

International kinship

European kinship

EN ISO 3741:2010
Sumary
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).

Replaced standards (1)
NF EN ISO 3741
November 2009
Standard Cancelled
Acoustics - Determination of sound power levels of noise sources using sound pressure - Precision methods for reverberation rooms

Le présent document fait partie d'une série de normes spécifiant diverses méthodes de détermination des niveaux de puissance acoustique des machines et des équipements. Il spécifie une méthode directe et une méthode de comparaison, ainsi que des exigences concernant la salle d'essai, l'emplacement de la source et ses conditions de fonctionnement, l'appareillage, pour le calcul du niveau de puissance acoustique de la machine. Il vient à l'appui des exigences essentielles de la Directive Nouvelle approche 98/37/CE, amendée par la Directive 98/79/CE ainsi que de la Directive Nouvelle approche 2006/42/CE, sur les machines.

Table of contents
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  • Avant-propos
    iv
  • Introduction
    v
  • 1 Domaine d'application
    1
  • 2 Références normatives
    2
  • 3 Termes et définitions
    2
  • 4 Conditions météorologiques de référence
    6
  • 5 Salle d'essai réverbérante
    6
  • 6 Appareillage et dispositif de mesure
    10
  • 7 Définition, emplacement, installation et fonctionnement de la source de bruit en essai
    11
  • 8 Mesurages en salle d'essai réverbérante
    13
  • 9 Détermination des niveaux de puissance acoustique et des niveaux d'énergie acoustique
    20
  • 10 Incertitude de mesure
    28
  • 11 Informations à enregistrer
    31
  • 12 Rapport d'essai
    33
  • Annexe A (informative) Lignes directrices pour la conception des salles d'essai réverbérantes
    34
  • Annexe B (informative) Lignes directrices pour la conception des diffuseurs tournants
    36
  • Annexe C (normative) Méthode de qualification d'une salle d'essai réverbérante pour le mesurage de bruits à large bande
    37
  • Annexe D (normative) Méthode de qualification d'une salle d'essai réverbérante pour le mesurage de composantes à fréquence discrète
    39
  • Annexe E (informative) Extension du domaine de fréquences en dessous de 100 Hz
    44
  • Annexe F (normative) Calcul des niveaux de puissance acoustique et des niveaux d'énergie acoustique par bandes d'octave, des niveaux de puissance acoustique pondérés A et des niveaux d'énergie acoustique pondérés A à partir des niveaux par bande d'un tiers d'octave
    47
  • Annexe G (informative) Lignes directrices pour l'élaboration de données sur l'incertitude de mesure
    50
  • Bibliographie
    62
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