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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DAkkS D-PL-14358-01-01 Frankfurt (Oder), DE
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Feinmess Suhl

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Parallelendmaße 0,5 mm bis DIN EN ISO 3650:1999 Messschieber für 0 mm Außen-, Innen- und > 300 mm + 3 more
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DAkkS D-PL-21240-01-00 Lingen (Ems), DE
DIN EN 13725:2003-07 und Berichtigung
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DIN 32753-1
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DAkkS D-K-15088-01-00 Köln, DE
flexiblen Akkreditierungsbereich. Beschleunigung * 10 m/s Beschleunigungsaufnehmer Beschleunigungsaufnehmer 10 m/s digital (DTI) + 3 more
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DAkkS D-K-21624-01-01 Riedlingen, DE
Kraft (WPM) Vibration measuring instruments — test m Acoustics — tonality assessment (DIN 456 Härteprüfmaschinen Länge (WPM) + 3 more
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DAkkS D-PL-14116-01-00 Gräfelfing, DE
DIN EN ISO 8497 ISO 8301 ISO 8302 DIN EN 12664 DIN EN 12667 + 3 more
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DAkkS D-ML-21105-01-01 Penzberg, DE
(somatische genetische ACVR1B, AKT1, AKT2, AKT3, ALOX12B, AMER1 GATA3, GATA4, GATA6, GID4, GNA11,GNA13, CHEK2, CHIC2, CHN1, CIC, CIITA IRF8, IRS2, ITK, JAK1, JAK2, JAK3, JARID + 3 more
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DAkkS D-PL-21039-04-04 Erlangen, DE
DIN EN ISO 10304-1 DIN EN ISO 11885 DIN EN ISO 15350 DIN EN ISO 15351 DIN EN ISO 17294-2 + 3 more
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DAkkS D-K-21039-01-00 Erlangen, DE
- Gleichspannung Messgeräte 0,33 V bis < 3,3 V 330 V Quellen > 0,1 V + 3 more
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DAkkS D-K-17452-01-00 Schalkau, DE
Kraft (WPM) 30 N Vibration measuring instruments — test m maschinen nach DIN Kraft * 10 N Acoustics — tonality assessment (DIN 456 + 3 more
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DAkkS D-PL-11140-11-01 Stuttgart, DE
DIN EN ISO 717-1 DIN EN ISO 717-2 DIN EN ISO 10140-1 DIN EN ISO 10140-2 DIN EN ISO 10140-3 + 3 more
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DIN ISO 16000-3 DIN EN ISO 12460-3 DIN EN ISO 12460-4 DIN EN ISO 12460-5 100 HV 120 + 3 more
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DAkkS D-K-11140-02-00 Freiburg, DE
Tensile testing of metallic materials (I Vickers hardness test (ISO 6507) Kurzschlussstrom Solarmodule 16 mA Gleichstrom- und Nieder- 10 mV + 3 more
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DAkkS D-K-15109-01-01 Titisee-Neustadt, DE
Druck * Absolutdruck Pabs 1 bar; 3 bar Negativer und positiver Überdruck + 3 more
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DAkkS D-PL-14170-01-03 Hamburg, DE
DIN EN 12579 DIN 19698-1 DIN 19698-2 DIN 51750-2 DIN ISO 11277 + 3 more
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DAkkS D-PL-19633-01-00 Dresden, DE
DIN 38402-A 12 DIN EN ISO 5667-6 (A 15) DIN 38402-A 30 DIN EN ISO 5667-13 (S 1) DIN 38414-S 11 + 3 more
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DAkkS D-PL-17559-01-00 Bexbach, DE
DIN EN 50173-1 DIN EN 50173-2 DIN EN 50173-3 DIN EN 50173-4 DIN EN 50173-5 + 3 more
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DAkkS D-PL-17563-01-00 Stuhr, DE
DIN EN 12469 BS 5726-1 DIN 1946-4 DIN EN 12599 DIN 12980 + 1 more
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DAkkS D-PL-11085-01-00 Frankfurt am Main, DE
DIN 51757 DIN EN ISO 12185 DIN EN ISO 3405 DIN EN 13016-1 DIN EN 237 + 3 more
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DAkkS D-K-11243-01-00 Stade, DE
Koordinatenmesstechnik Lasertracker* 0,5 m 1) In den CMC sind die erweiterten Messu Bügelmessschrauben* 0 mm + 3 more
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GMC-I Service

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DAkkS D-K-20313-01-01 Nürnberg, DE
- Gleichspannung Messgeräte > 0,22 V > 2,2 V > 11 V > 22 V + 3 more
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DAkkS D-PL-14479-01-00 Würzburg, DE
DIN EN ISO 5667-1 (A 4) DIN 38402-A 11 DIN 38402-A 12 DIN 38402-A 13 DIN EN ISO 5667-6 (A 15) + 3 more
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DAkkS D-ML-13406-01-00 Rüsselsheim, DE
Erythrozytenzahl Hämatokrit Leucozytendifferenzierung Leucozytenzahl MCV + 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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