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-K-15115-01-00 Kassel, DE
- Gleichspannung Josephson-Josephson Multimeter Quellen > 0,2 V Spannungsnormale + 3 more
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UKAS 4236 Northampton, GB
cartridges, based on HTM 2030 9.201 to 9.212 and BS EN ISO 35 °C/3 days based on HTM 2030 section 9.201 to 9.212, BS EN ISO 15883-1:2009 6.4.2.3 and + 3 more
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DAkkS D-K-15158-01-00 Haiger, DE
Sound intensity — scanning method (ISO 9 Härteprüfmaschinen Knoop- und 70 HR15N 42 HR30N + 3 more
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DAkkS D-K-18164-01-00 Partenstein, DE
Metrologic, Software von Metrologic Group ≤ 9090 mm CAM 2, Software von Münchingen, D Chur, CH, ≤ 5000 mm + 3 more
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UKAS 0173 London, GB
(HSG 264, 2012)
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UKAS 1931 London, GB
(HSG 248) – 2021 E203 based on HSG 248 (PCM) based on HSG 248 E200 based on HSG 248 E201 based ISO 14966:2019 using + 1 more
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UKAS 9372 West Chiltington, GB
(HSG 264, 2012)
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DAkkS D-K-21981-01-00 Konstanz, DE
8tree Scanner / 0 mm bis 100 mm Laterale Größe von Tiefenmaß/ -unterstand (Härteskalen HV0,01
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DAkkS D-K-21221-01-00 Altenbuch, DE
Vickers hardness test (ISO 6507) Koordinatenmessgeräte Koordinatenmessger Steuerungssoftware Messvolumen mit einer Metromec CM, Software Raumdiagonale von von Metromec Software ≤ 750 mm + 3 more
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UKAS 9260 Dukinfield, GB
(HSG 264, 2012)
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ACCREDIA 00007 Vigevano, IT
DIN ISO 1817 ISO 4045 DIN EN ISO 20347 ISO 17697 ISO 4643 + 3 more
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ACCREDIA 00925 Napoli, IT
ASTM E 415 21 DIN EN 10164 DIN EN ISO 3651-1 ASTM A 262-15 ASTM G48-11 + 3 more
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DAkkS D-K-17303-01-01 Dresden, DE
Kraft 0,5 N Zug- und Druckkraft Vibration measuring instruments — requir Sound power — in-situ using reference so 20 kN + 3 more
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COFRAC 1-2303 Thiant, FR
ASTM E8/E 8M DIN EN 10002-1 ASTM E 21 DIN EN 10002-5 DIN EN ISO 6892-2 + 3 more
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COFRAC 1-6312 Gardanne, FR
DIN EN 27888 DIN EN ISO 10523 DIN EN ISO 7393-2 NF X 31-615 (Uniquement
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COFRAC 1-7214 Florange, FR
NF X 43-269 NF X 43-264 DIN EN ISO 16017-2 NF X 43-257 NF X 43-267 + 1 more
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A2M INDUSTRIE

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COFRAC 1-1249 Fraisses, FR
(BS EN ISO 6892-1: 2019) DIN EN 10002-1 ISO 6892-1 -2009 ASTM E8/E 8M ISO 6892-1 -2016 + 3 more
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ENAC LE2968 Palmera, ES
UNE-EN ISO 16283-2 UNE-EN ISO 16283-1 UNE-EN ISO 16283-3
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ENAC LE229 Vitoria-Gasteiz, ES
Environmental noise — determination of s UNE-EN ISO 3744 UNE-EN ISO 3746 UNE-EN ISO 11200 UNE-EN ISO 11201 + 3 more
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ENAC LE2773 Madrid, ES
UNE-EN ISO 16283-2 UNE-EN ISO 16283-1 UNE-EN ISO 16283-3
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DAkkS D-K-12115-01-00 Minden, DE
Absolutdruck p abs positiver Überdruck Positiver Überdruck p e Überdruck p + 3 more
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DAkkS D-PL-14560-01-00 Teltow, DE
DIN ISO 8297 DIN 45645-1 DIN 45645-2 DIN 45680 Beiblatt 1 ISO 11338-2 + 2 more
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UKAS 4021 Rogerstone, GB
TEMPERATURE PRESSURE AC VOLTAGE (continued) DC VOLTAGE Generation only + 3 more
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UKAS 4494 Southampton, GB
(HSG 248) – 2021 staining based on HSG 248 QP23 based on HSG 248 (PCM) based on HSG 248
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AC & MS

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UKAS 2742 Canvey Island, GB
Analysts’ Guide (HSG 248) (PCM) based on HSG 248
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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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