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
1,670 Accredited labs
18 Countries

Showing 376–400 of 1,670 labs

DAkkS D-PL-17009-34-00 Sankt Augustin, DE
DIN 58620: 2007-02 DIN 58621: 2011-10 DIN 58647-7: 1997-12 ID136 > 140 + 3 more
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DAkkS D-PL-18020-01-01 Varel, DE
IEC 61400-12 IEC 61400-12-1 IEC 61400-12-2 IEC 61400-12-3 IEC 61400-12-5 + 3 more
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DAkkS D-K-11170-01-00 Hamburg, DE
Railway brakes — conditions for homologa − Durchfluss von Flüssigkeiten − Strömungsgeschwindigkeit von Gasen − Widerstandsthermometer − Temperatur-Transmitter, Datenlogger + 3 more
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DAkkS D-ML-13068-01-00 Berlin, DE
ADP ASPI TRAP Amiodaron, Desethylamiodaron Mycophenolsäure + 3 more
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UKAS 0254 Plymouth, GB
Specific Values 1  RF Power RF Attenuation 10 MHz to 1 GHz Other values -20 dBm to +20 dBm
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UKAS 0687 Devonport, GB
BS 4206:1967 (superseded) ISO 5173 ISO 7438 BS EN ISO 9606-2:2004 BS 131-5:1965 + 3 more
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Diagenom

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DAkkS D-ML-18903-01-00 Rostock, DE
Chromosomensatz (angeboren) Chromosomensatz (erworben) Adrenogenitales Syndrom Angelman-Syndrom (15q11-Region, UBE3A) Mikrodeletionen; AZFa-c) + 3 more
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Diagnos MVZ

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DAkkS D-ML-21150-01-00 Berlin, DE
HbA1c Differentialblutbild, maschinell Retikulozyten, maschinell Kleines Blutbild Thrombozyten + 3 more
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UKAS 0798 Hamilton, GB
AUDIOMETRIC EQUIPMENT Attenuator linearity Microphones EAR SIMULATORS Class LS, 1 and 2
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DAkkS D-K-19516-01-00 Ansbach, DE
Volumen strömender 0,0005 m − Durchfluss von Flüssigkeiten 0,025 m Wasserzähler und 0,001 m Durchflusssensoren + 3 more
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UKAS 0560 Bingley, GB
TIME INTERVAL TEMPERATURE parameters and ranges)
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DAkkS D-K-20015-01-01 Lahr, DE
Absolutdruck p * Vickers hardness test (ISO 6507) Flüssigkeitsvolumen * variablem Volumen aufnehmern sowie + 3 more
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DAkkS D-ML-13252-01-01 München, DE
Blutbild groß Thrombozyten Urinsediment Natrium Kalium + 3 more
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DAkkS D-ML-19642-02-00 Ronnenberg, DE
Aminosäureprofil Guanidinoacetat Kreatin Hämoglobinprofil Nitisinon (NTBC), Succinylaceton + 3 more
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Druck

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UKAS 0221 Groby, GB
Gas pressure (absolute) Hydraulic pressure (gauge) Gas pressure (gauge) (At low current) Specific values (continued) + 3 more
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DAkkS D-K-11250-01-00 Lübeck, DE
Druck * Negativer und positiver Überdruck -0,01 bar Positiver Überdruck p e > 0,015 bar + 3 more
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Duravit

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DAkkS D-PL-21217-01-00 Hornberg, DE
*6095991, BAG3 [OMIM *6038831 (-13910T>C) rs4988235 - PiM rs6647, PiZ rs28929474, rs17580 DIN EN 997 DIN EN 13407 + 3 more
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UKAS 29302 Lower Earley, GB
DIN EN 14791 IEC 60519-11 BS EN ISO 16911-1:2013 using DIN EN 14792 DIN EN 13126-19 + 3 more
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E C L (2000)

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UKAS 0709 Forest Hall, GB
(PCM) based on HSG 248) (HSG 248) – 2021
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DAkkS D-PL-12144-01-01 Altdorf, DE
VDE 0468-2-1 VDE 0468-2-2 VDE 0468-2-6 DIN EN IEC 60068-2-11 DIN EN IEC 60068-2-13 + 3 more
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DAkkS D-K-18994-01-00 Pleidelsheim, DE
optische 0 mm Werkzeugeinstell- und / Messgeräte verwendete Abkürzungen:
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COFRAC 1-7055 Nice, FR
DIN EN ISO 17294-2 DIN EN ISO 7899-1 ISO 5815-1 NF T90-015-1 DIN EN ISO 10523 + 3 more
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ACCREDIA 00160 Bassano del Grappa, IT
EPA 3535 DIN EN ISO 15587-1 NF EN ISO-15587-2 EPA 5030 EPA 6010 + 3 more
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ENAC LE2175 Arroyo de la Encomienda, ES
UNE-EN ISO 16283-1 UNE-EN ISO 16283-3 UNE-EN ISO 16283-2 UNE-EN ISO 3382-1 UNE-EN ISO 3382-2
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DAkkS D-PL-11061-02-02 Petersberg, DE
DIN 40633-2 DIN 40633-3 DIN 53482 DIN 72551-100 DIN 72551-6 + 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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