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
1,868 Accredited labs
20 Countries

Showing 1,176–1,200 of 1,868 labs

DAkkS D-ML-13238-01-01 Göttingen, DE
Obligat anaerobe Bakterien Grampositive aerobe und anaerobe Kokken Enterokokken Mikrokokken + 3 more
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DAkkS D-ML-13445-01-01 Wernigerode, DE
automatische Zelldifferenzierung Erythrozyten Leukozyten Retikulozyten Thrombozyten + 3 more
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DAkkS D-K-15048-01-01 Allmersbach im Tal, DE
Parallelendmaße * 0,5 mm DIN EN ISO 3650:1999 Parallelendmaße > 100 mm Messschieber für Außen-, 0 mm + 3 more
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UKAS 9019 Erith, GB
BS EN 14876:2007/Internal proceduresDiss BS EN ISO 18119:2018+A1:2021 BS EN ISO 22434:2011 BS EN ISO 10460:2018 BS EN ISO 13769:2018
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UKAS 0373 Coventry, GB
tungsten carbide) Plain ring gauges (taper) Straight edges LENGTH (cont’d) Squares + 3 more
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DAkkS D-K-21403-01-01 Aichhalden, DE
Metrosoft CM, Software einer Raumdiagona AG, Chur, CH ≤ 3333 mm Oberkochen, D GmbH, Wetzlar, D AG, Chur, CH ≤ 7500 mm
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DAkkS D-K-19120-01-01 Gießen, DE
Flüssigkeitsvolumen * Kolbenhubpipetten Manuell betätigte spritzen Mehrfachdispenser + 3 more
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DAkkS D-K-15086-01-01 Wedel, DE
- Gleichspannung Messverstärker > 120 mV > 1 V > 12 V > 1000 V + 3 more
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UKAS 0511 Kingswinford, GB
LENGTH Caliper Depth BS 6468: 2008, 0 to 300 Depth Dial gauges and dial + 2 more
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UKAS 4007 Scunthorpe, GB
(HSG 248) – 2021 (PCM) based on HSG 248
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UKAS 0405 Scunthorpe, GB
(HSG 264, 2012)
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DAkkS D-K-19573-01-00 Gefell, DE
Akustische Messgrößen Messmikrofone nach (DIN EN 61094-4:1996) Schalldruckpegel (Druck) Empfangsübertragungsmaß + 3 more
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UKAS 1899 Bournemouth, GB
ISO 7251 # = 100 A ISO 6888-3 1) A:2b based on ISO 4833-2:2013 Amd 1:2 2) A:6c based on ISO 21528-1:2017 by mos + 1 more
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ACCREDIA 01676 Biassono, IT
ASTM B212-21 ASTM E1019-24 ASTM B527-24 BS EN ISO 3923-1 ASTM B417-22 + 3 more
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DAkkS D-K-20451-01-00 Bovenden, DE
Konventioneller Wägewert/ Massenormale Charpy impact test (ISO 148-1) Salt spray / neutral salt fog test (ISO + 3 more
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DAkkS D-ML-19288-01-00 Stuttgart, DE
Bacillus cereus Toxin Clostridium perfringens Salmonella spp. Shigella spp. Staphylococcus aureus Toxin + 3 more
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ACCREDIA 02288 Roma, IT
ETSI EN 319 412 ETSI EN 319 401 ETSI EN 319 411-2 ETSI EN 319 411-1
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UKAS 0509 Negara, BN
Specific Values Specific values (continued) ELECTRICAL Other Values AC CURRENT + 3 more
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UKAS 0317 Derby, GB
(HSG 264, 2012) Appendix 5 of HSG 227 (2004))
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DAkkS D-K-15096-01-00 Neuss, DE
Parallelendmaße 0,5 mm DIN EN ISO 3650:1999 Parallelendmaße > 10 mm Parallelendmaße > 100 mm + 3 more
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DAkkS D-K-21161-01-01 Esslingen, DE
Gleichspannung 3 mV Messgeräte 10 mV > 100 mV > 220 mV > 11 V + 3 more
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DAkkS D-PL-12005-01-01 Itzehoe, DE
IEC 61000-4-7 IEC 61000-4-15 IEC 61000-4-30 IEC 61400-21 IEC 61400-21-1 + 3 more
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DAkkS D-K-11292-01-00 Buchen Odenwald, DE
Temperatur 50 °C Railway brake handbooks (UIC 547) 1) In den CMC sind die erweiterten Messu
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UKAS 22138 Cannock, GB
DC CURRENT Gas pressure (gauge) ELECTRICAL DC VOLTAGE Measurement + 3 more
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DAkkS D-PL-19306-01-00 Oppenweiler, DE
IEC 61000-4-2: 2008 VDE 0847-4-2 IEC 61000-4-3: 2006 VDE 0847-4-3 IEC 61000-4-4: 2012 + 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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