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 4150-1 DIN 4150-2 DIN 4150-3 DIN EN 61800-5-1: 2017
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COFRAC 1-1483 Moncel-Les-Luneville, FR
NF EN ISO 1927-3 NF EN ISO 1927-5 ASTM C 862 ASTM C 865 (DIN EN 61094-4:1996) + 3 more
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DIN EN 1385 EN 17092-1:2020 DIN EN ISO 5077 EN 1317-1 DIN EN ISO 13688 + 3 more
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IEL

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DAkkS D-PL-11011-01-02 Aurich, DE
DIN 45691
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DIN EN ISO 17892-2 DIN EN ISO 17892-3 DIN EN ISO 17892-4 DIN 18121-2 DIN 18125-2 + 3 more
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DAkkS D-K-11332-01-02 Leipzig, DE
Kraft 10 kN Sound power — survey method (ISO 3746) Radaufstandskraft- 10 kN Prüfkraftmesseinrichtung Länge 10 mm
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DAkkS D-PL-20186-01-00 Düsseldorf, DE
DIN EN 61800-5-1: 2017
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HbA1c Vitamin A Vitamin B1 Vitamin B2 Vitamin B6 + 3 more
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COFRAC 1-0847 Foulayronnes, FR
NF X 45-301 NF X 45-302 NF X 45-303 ASTM F795-88 NF P 90-319 de 02/2011 + 3 more
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UNE-EN 60942 UNE-EN 61672-3 UNE-EN 60804 UNE-EN 60651 UNE-EN 61252 + 1 more
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Thrombozytenaggregometrie Drogen- und Medikamentenscreening Freie Fettsäuren Linolensäure, Eicosapentaensäure + 3 more
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ACCREDIA 01178 Arzignano, IT
UNI EN 17702-2 DIN EN 15476 ISO 14820-2 NF EN 13520 ISO 17704 EN 17703 + 2 more
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ASTM F1978 ASTM G195 DIN EN ISO 4287 DIN EN ISO 4288 DIN EN ISO 5470-1 + 3 more
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Temperaturanzeigegeräte –100 °C - Thermopaare, Thermoelemente Typ J, K und N für Widerstands- –100 °C - Direktanzeigende Thermometer + 3 more
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HbA1c Eosinophile, Basophile, MCV, MCH) Retikulozyten Urinsediment Elektrolyte (Kalium, Natrium, Chlorid) + 3 more
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COFRAC 1-6403 Marrakech, MA
DIN EN ISO 7932 DIN EN ISO 6579-1 DIN EN ISO 7937 DIN EN ISO 11290-1 0.95) based on BS ISO 21527-2:2008 + 2 more
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ACCREDIA 00013 Milano, IT
DIN EN 62053-23: 2017-09 DIN EN ISO 11816-1 IEC 62109-1 IEC 60598-2-2 DIN EN 62053-24 + 3 more
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ACCREDIA 00529 Amaro, IT
DIN EN 14511-2 DIN EN 13141-7 DIN EN 60704-2-10 DIN EN 16147 IEC 60704-2-1 + 3 more
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ACCREDIA 00060 Castel Mella, IT
DIN EN ISO 10705-2 ISO 11731 DIN EN 15634-1 ISO 15705 EPA 353.2 1993 + 3 more
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ENAC LE2176 Sabadell, ES
SM 2120 SM 4500-Cl G UNE EN 27888 SM 4500-H+ B SM 2130 + 3 more
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UNE-EN 15259 UNE-EN 13284-1 UNE 77225 EPA 8 UNE 77227 + 3 more
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NF T 70-503 NF T 70-501 NF T 70-507 NF T 70-504 NF T 70-502 + 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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