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EN ISO 3744:2026

Acoustics - Determination of sound power levels of noise sources using sound pressure - Engineering methods for an essentially free field over a reflecting plane (ISO 3744:2025, including corrected version 2026-01)

Edition date: 2026-03-11
In Force
Available languages: English, French
Summary: 1.1 Allgemeines Dieses Dokument legt Verfahren für die Bestimmung des Schallleistungspegels einer Geräuschquelle aus Schalldruckpegeln fest, die auf einer Fläche gemessen werden, die die Geräuschquelle (eine Maschine oder ein Gerät) umschließt (Hüllfläche), wobei sich die Geräuschquelle in einer Umgebung befindet, die angenähert einem akustischen Freifeld in der Nähe einer oder mehrerer reflektierender Ebenen entspricht. Der an der Geräuschquelle, in Frequenzbändern oder durch A-Bewertung, erzeugte Schallleistungspegel wird durch diese Messungen berechnet. ANMERKUNG Unterschiedlich geformte Messflächen können unterschiedliche Schätzwerte des Schallleistungspegels einer bestimmten Geräuschquelle ergeben, die durch die Unsicherheit dieses Prüfverfahrens berücksichtigt werden. Eine ordnungsgemäß erstellte Geräuschmessnorm (siehe ISO 12001) enthält Einzelheiten zur Auswahl der Oberfläche. 1.2 Arten des Geräusches und der Geräuschquellen Die in diesem Dokument festgelegten Verfahren eignen sich für alle in ISO 12001 definierten Geräuscharten (gleichförmige, ungleichförmige und schwankende), mit Ausnahme von kurzzeitigen, impulshaltigen Ereignissen. Dieses Dokument gilt für Geräuschquellen aller Art und Größe (z. B. eine stationäre oder sich langsam fortbewegende Komponente oder Baugruppe), sofern die Messbedingungen erfüllt werden können. ANMERKUNG Die in diesem Dokument beschriebenen Messbedingungen können in der Praxis bei sehr hohen oder sehr langen Geräuschquellen wie Schornsteinen, Kanälen, Förderbändern und Industrieanlagen mit vielen Geräuschquellen möglicherweise zu Schwierigkeiten führen. In solchen Fällen können in einer Geräuschmessnorm für die Bestimmung der Geräuschemission solcher speziellen Quellen alternative Verfahren angegeben sein. 1.3 Messumgebung Als Umgebung zur Durchführung von Messungen nach diesem Dokument eignet sich ein Ort in einem geschlossenen Raum oder im Freien, der eine oder mehrere schallreflektierende Ebenen aufweist, auf der oder in deren Nähe die zu untersuchende Geräuschquelle angeordnet wird. Die ideale Umgebung ist ein vollständig offener Raum mit keinen anderen Begrenzungs- oder Reflexionsflächen als der (den) reflektierenden Ebene(n) (wie zum Beispiel ein qualifizierter reflexionsarmer Halbraum), jedoch werden für den Fall von nichtidealen Umgebungen auch Verfahren zur Anwendung von Korrekturen (innerhalb festgelegter Grenzen) angegeben. Anhang A oder ISO 26101 2 legt Verfahren für die Feststellung der Eignung der Messumgebung und für die Bestimmung von Korrekturen fest, die durchzuführen sind, um den Einfluss der Messumgebung zu berücksichtigen. 1.4 Messunsicherheit Es werden Angaben zur Unsicherheit der nach diesem Dokument aus Messungen in Frequenzbändern und mit A-Bewertung bestimmten Schallleistungspegel gemacht. Anhang I legt Verfahren fest, die von Prüflaboratorien angewendet werden können, um Messunsicherheiten zu verringern. Die Unsicherheit entspricht ISO 12001, Genauigkeitsklasse 2. Allgemeine Informationen zur Messunsicherheit sind in diesem Dokument enthalten, und zusätzliche Informationen können ISO 5114 1 entnommen werden.

1.1        General This document specifies methods for determining the sound power 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 produced by the noise source, in frequency bands or with A-weighting applied, is calculated using those measurements. NOTE   Differently shaped measurement surfaces can yield differing estimates of the sound power level of a given noise source which are accounted for in the uncertainty associated with this test method. An appropriately drafted noise test code (see ISO 12001) gives detailed information on the selection of the surface. 1.2        Types of noise and noise sources The methods specified in this document are suitable for all types of noise (steady, non-steady, and fluctuating) as defined in ISO 12001, except for short duration, impulsive events. This document is applicable to all types and sizes of noise source (e.g. stationary or slowly moving component or sub-assembly), provided that the conditions for the measurements can be met. NOTE   It is possible that the conditions for measurements given in this document are impracticable for very tall or very long sources such as chimneys, ducts, conveyors and multi-source industrial plants. A noise test code for the determination of noise emission of specific sources can provide alternative methods in such cases. 1.3        Test environment The test environments that are applicable for measurements made in accordance with this document 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. Annex A or ISO 26101-2 specifies methods for determining the adequacy of the test environment and for determination of corrections to be applied to account for the effect of the test environment. 1.4        Measurement uncertainty Information is given on the uncertainty of the sound power levels determined in accordance with this document, for measurements made in limited bands of frequency and with frequency A-weighting applied. Annex I specifies procedures for testing laboratories that can be used to reduce measurement uncertainty. The uncertainty conforms to ISO 12001, accuracy grade 2 (engineering grade). General information on measurement uncertainty is provided in this document and additional information can be found in ISO 5114-1[8].

1.1        Généralités Le présent document spécifie des méthodes de détermination du niveau de puissance acoustique émis par une source de bruit à partir des niveaux de pression acoustique mesurés sur une surface entourant la source de bruit (machine ou équipement), dans des conditions approchant celles du champ acoustique libre au voisinage d’un ou de plusieurs plans réfléchissants. Le niveau de puissance acoustique produit par la source de bruit, par bandes de fréquences ou avec la pondération A appliquée, est calculé en utilisant ces mesures. NOTE   Des surfaces de mesure de formes différentes peuvent produire des estimations différentes du niveau de puissance acoustique d’une source de bruit donnée qui sont prises en compte dans l’incertitude associée à cette méthode d’essai. Un code d’essai acoustique rédigé de façon appropriée (voir l’ISO 12001) apporte des informations détaillées sur le choix de la surface. 1.2        Types de bruits et sources de bruit Les méthodes spécifiées dans le présent document sont applicables à tous les types de bruit (stable, non stable, fluctuant) définis dans l’ISO 12001, à l’exception des événements impulsifs de courte durée. Le présent document s’applique à tous les types de sources de bruit, quelles que soient leurs dimensions (par exemple composant ou sous-ensemble fixe ou se déplaçant lentement), sous réserve de pouvoir satisfaire les conditions de mesure. NOTE   Dans le cas de sources particulièrement hautes ou longues (cheminées, conduits, convoyeurs, installations industrielles comprenant plusieurs sources), les conditions de mesure prescrites dans le présent document peuvent s’avérer impraticables. Dans ce cas, un code d’essai acoustique pour la détermination de l’émission sonore d’un type spécifique de sources peut fournir d’autres méthodes. 1.3        Environnement d’essai Les environnements d’essai qui sont applicables aux mesurages réalisés conformément au présent document peuvent être en salle ou en plein air, comprendre un ou plusieurs plans acoustiques réfléchissants sur lesquels ou à proximité desquels est montée la source de bruit en essai. L’environnement idéal est un espace complètement libre, dépourvu de surfaces limites ou réfléchissantes autres que le ou les plans réfléchissants, tels que ceux d’une salle semi-anéchoïque qualifiée, mais des procédures sont fournies pour appliquer des corrections (dans des limites spécifiées) lorsque ces environnements ne correspondent pas à ces conditions idéales. L’Annexe A ou l’ISO 26101-2 spécifie des méthodes pour déterminer l’adéquation de l’environnement d’essai ainsi que les corrections à appliquer pour tenir compte de l’effet d’environnement. 1.4        Incertitude de mesure Des informations sont données sur l’incertitude associée aux niveaux de puissance acoustique déterminés conformément au présent document pour des mesurages effectués dans des bandes de fréquences limitées et avec la pondération fréquentielle A. L’Annexe I spécifie les procédures destinées aux laboratoires d’essais qui peuvent être utilisées pour réduire l’incertitude de mesure. L’incertitude est conforme à celle de la classe de précision 2 (classe expertise) définie dans l’ISO 12001. Des informations générales sur l’incertitude de mesure sont fournies dans le présent document et des informations supplémentaires sont disponibles dans l’ISO 5114-1[8].
ICS: 17.140.01-Acoustic measurements and noise abatement in general
CTN: CEN/TC 211 - 6192

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