ISO 3744

Sound power — enveloping surface engineering method

ISO 3744 specifies the engineering method for determining sound power and sound energy levels using sound pressure measurements obtained on an imaginary surface (hemispherical or parallelepiped) surrounding a noise source. This method is widely used for in-situ testing of machinery, industrial equipment, and large installations where reverberation room testing is impractical. It provides a practical balance between accuracy and field applicability, making it suitable for machinery compliance testing, environmental noise assessments, and product CE marking requirements across the EU. ISO 17025 accreditation confirms laboratory proficiency in sound field measurement, environmental parameter correction, and uncertainty quantification for this complex measurement method.

What it measures

  • Sound power level (Lw) using enveloping surface pressure data
  • A-weighted and frequency-weighted sound power
  • Octave and one-third-octave band sound power (63 Hz to 8 kHz)
  • Environmental and measurement corrections
  • Sound power directivity and spatial variability
🇩🇪 DIN EN ISO 3740 🇬🇧 BS EN ISO 3740 🇫🇷 NF EN ISO 3740 🇮🇹 UNI EN ISO 3740 🇪🇸 UNE EN ISO 3740 🇳🇱 NEN EN ISO 3740 🇩🇪 DIN EN ISO 3743-1 🇬🇧 BS EN ISO 3743-1 🇫🇷 NF EN ISO 3743-1 🇮🇹 UNI EN ISO 3743-1 🇪🇸 UNE EN ISO 3743-1 🇳🇱 NEN EN ISO 3743-1
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E. ZOLLER GmbH & Co. KG Einstell- und Messgeräte

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optische 0 mm Werkzeugeinstell- und / Messgeräte verwendete Abkürzungen:
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EDAG Engineering GmbH ATC Fulda

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DAkkS D-PL-11061-02-02 Petersberg, DE
DIN 40633-2 DIN 40633-3 DIN 53482 DIN 72551-100 DIN 72551-6 + 3 more
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ELLAB

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DAkkS D-K-20746-01-00 Bockel, DE
Taupunkttemperatur Widerstandssensor –100 °C bis > 140 °C bis > 240 °C bis + 3 more
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ELMTEC Ingenieurgesellschaft

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DAkkS D-K-15099-01-01 Königslutter am Elm, DE
- Gleichspannung Messgeräte > 0,004 V > 0,33 V > 33 V > 330 V + 3 more
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EMCCons RASEK

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DAkkS D-K-12067-01-01 Unterleinleiter, DE
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EP EHRLER PRÜFTECHNIK ENGINEERING

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DAkkS D-K-21444-01-01 Niederstetten, DE
Railway brake — anti-slide device (UIC 5 Railway brake — magnetic track brakes (U Railway brakes — conditions for homologa Railway brakes — disc brake pads (UIC 54 − Durchfluss von Gasen + 3 more
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ERGO Umweltinstitut

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DAkkS D-PL-14613-01-03 Dresden, DE
DIN ISO 10381-5 DIN ISO 18400-102 DIN ISO 18400-104 DIN ISO 18400-105 DIN ISO 18400-203 + 3 more
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ESI Prüftechnik

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DAkkS D-K-18808-01-01 Wendlingen, DE
Sound intensity — scanning method (ISO 9 Härteprüfmaschinen Kraft einrichtungen * Vibration measuring instruments — test m + 3 more
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ETAS

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DAkkS D-K-19158-01-00 Stuttgart, DE
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EXcorLab

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DAkkS D-PL-19275-02-01 Obernburg, DE
DIN EN ISO 1135-4 EN ISO 1135-5 DIN EN ISO 10993-1 DIN EN ISO 8637-1 DIN EN ISO 7199 + 2 more
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Eckert & Ziegler Nuclitec

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Elektro Struß

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Elektro Wilhelm

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DAkkS D-K-20306-01-00 Weinstadt, DE
Taupunkttemperatur für Widerstands- ˃ 500 °C - Direktanzeigende Thermometer Thermoelemente ˃ 500 °C Widerstands- -50 °C + 3 more
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Element Metech

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DAkkS D-K-15020-04-01 Norderstedt, DE
/ Messgeräte 0,001 V > 0,22 V > 2,2 V > 22 V + 3 more
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Element Metech KDK

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DAkkS D-K-15180-01-01 Wiesloch, DE
Elektrische Messgrößen Gleichstrom- und Niederfrequenzmessgröße Railway brake — magnetic track brakes (U − Gleichspannung − Gleichstromstärke + 3 more
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Elster

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DAkkS D-K-19495-01-01 Mainz-Kastel, DE
Durchfluss von Gasen 0,5 m³/h Volumendurchfluss > 4 m³/h Railway overhead lines — pantograph head > 10 m³/h + 3 more
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Endolab Mechanical Engineering

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DAkkS D-PL-18838-02-01 Riedering, DE
DIN EN ISO 14607 DIN EN 13687-2 DIN EN ISO 15912 ASTM E290-22 DIN EN ISO 19023 + 3 more
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Endress+Hauser SE+

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DAkkS D-PL-15172-01-00 Maulburg, DE
IEC 61000-4-2: 2008 IEC 61000-4-3: 2006 IEC 61000-4-4: 2012 IEC 61000-4-5: 2005 IEC 61000-4-6: 2013 + 3 more
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Entwicklungs- und Prüflabor Holztechnologie

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CDC73 (NM_000384: c.1-c.82) ID152 EN ISO 11925-2 DIN EN 350 + 3 more
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Erichsen Gesellschaft mit beschränkter Haftung & Co. Kommanditgesellschaft

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DAkkS D-K-21247-01-01 Hemer, DE
Innen- und Tiefenmaße Konventioneller 0,11 G > 2 G > 5 g + 3 more
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Esenwein

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DAkkS D-K-15168-01-00 Hochdorf, DE
/ Messgeräte > 220 mV Quellen > 0,2 V 120 V 200 V + 3 more
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Eurofins Laborbetriebsgesellschaft Gelsenkirchen

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DAkkS D-ML-17481-01-01 Gelsenkirchen, DE
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Eurofins MVZ Medizinisches Labor Gelsenkirchen

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Europäisches Testzentrum für Wohnungslüftungsgeräte (TZWL) e. V.

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DAkkS D-PL-19438-01-00 Schwerte, DE
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Evangelisches Klinikum Niederrhein Laboratoriumsmedizin

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Glykohämoglobin A1C (HbA1c) Basophile Granulozyten Eosinophile Granulozyten Erythrozytenverteilungsbreite (RDW) + 3 more
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Industries

Industrial machinery manufacturers Construction equipment producers HVAC and ventilation systems Power generation and compressor suppliers Large transport and handling equipment makers

Related Standards

  • ISO 3740 Acoustics — Determination of sound power levels of noise sources — General guidelines
  • ISO 3743-1 Acoustics — Determination of sound power levels of noise sources — Part 1: Reverberation room method
  • ISO 3745 Acoustics — Determination of sound power levels of noise sources — Precision method using an enveloping surface

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