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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DIN EN 27888 DIN EN ISO 10523 NF X 31-615 (Uniquement prélèvements NF EN ISO 7887 Méthode D DIN EN ISO 9963-1 + 3 more
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DAkkS D-ML-13325-01-00 Cottbus, DE
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UKAS 0789 Great Dunmow, GB
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UKAS 1079 Gloucestershire, GB
BS ISO 488:2008, 2446:2008 and on BS 4401:Part 3:1970(1986) BS 696-2:1989 (superseded and BS ISO 6731:2010 ISO BS EN 3727-1:2002 + 3 more
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Carl Zeiss

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DAkkS D-K-12037-01-01 Jena, DE
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UKAS 27202 Paisley, GB
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UKAS 7914 Willsbridge, GB
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UKAS 1643 Chelmsford, GB
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COFRAC 1-1970 Chateauneuf Sur Isere, FR
DIN EN 12207 DIN EN 12208 DIN EN 1026 DIN EN 12210 BS EN 14351-1:2006+A2:2016 + 3 more
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ACCREDIA 01076 Reggio Emilia, IT
ISO 4650 DIN EN 13180 BS ISO 4650:2012 ISO 180
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ACCREDIA 00074 Lucca, IT
BS EN 13286-48:2005 DIN EN ISO 12625-6 DIN EN ISO 11664-5 DIN EN ISO 7263-1 DIN EN ISO 11646 + 3 more
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ACCREDIA 01957 Vigonza, IT
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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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