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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Bioscientia Institut für Medizinische Diagnostik GmbH Bioscientia MVZ Mainz

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Bioscientia Institut für Medizinische Diagnostik GmbH Bioscientia MVZ Nordrhein

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Bioscientia MVZ Labor Karlsruhe

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Birmingham City Council

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Bizerba SE &

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Bradley Environmental Consultants

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staining based on HSG 248 (HSG 248) – 2021 (PCM) based on HSG 248 (HSG 264:2012)
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Bremer Umweltinstitut Gesellschaft für Schadstoffanalytik und Begutachtung

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DAkkS D-PL-18812-01-02 Bremen, DE
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British Airways Engineering Wales

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UKAS 24592 Barry, GB
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British Engineering Services

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UKAS 9230 Warrington, GB
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Broadland Group

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Broomfield Carbide Gauges

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Broughton Life Sciences

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UKAS 10636 Earby, GB
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Brunel University London – Experimental Techniques Centre

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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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