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
1,868 Accredited labs
20 Countries

Showing 376–400 of 1,868 labs

ACCREDIA 01702 Milano, IT
ETSI EN 319 412 ETSI EN 319 401 ETSI EN 319 411-2 ETSI EN 319 411-1
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UKAS 6856 Basildon, GB
(HSG 248) – 2021 (HSG 264, 2012)
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UKAS 2522 Bradford, GB
requirements of BS EN 15259:2007 IEC 60519-11 Based on EN 14791:2017 DIN EN 13284-1 BS EN BS EN ISO 21877:2019 + 3 more
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DAkkS D-PL-14097-03-00 Dormagen, DE
DIN EN ISO 5136 DIN EN ISO 12354-4 DIN 45635-1 DIN 45635-14 DIN 45635-38 + 3 more
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Cybertech

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ACCREDIA 01852 Roma, IT
ETSI EN 319 412 ETSI EN 319 401 ETSI EN 319 411-2 ETSI EN 319 411-1
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DAkkS D-K-11081-02-01 Chemnitz, DE
Parallelendmaße * 0,5 mm DIN EN ISO 3650:1999 auch Vor-Ort Kalibrierung bahntypischer –0,26 mm + 3 more
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DAkkS D-PL-11072-01-01 Freiberg, DE
DIN EN ISO 9012 ISO 22967 ISO 22968 (SPG42), SPAST (SPG4), SPG11, SPG7, VAMP DIN EN 30-1-1 + 3 more
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DAkkS D-K-17567-01-01 Lauf a. d. Pegnitz, DE
(ein- und mehrgängige zylindrische Außen- und metrischem Profil) Außengewinde Nenndurchmesser Flankendurchmesser 1 mm + 3 more
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DAkkS D-PL-11060-03-05 Stuttgart, DE
DIN EN ISO 5667-3 DIN EN ISO 15587-2 DIN EN 12457-4 DIN EN 13346 DIN EN 13657 + 3 more
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RvA I327 Arnhem, NL
DIN EN 60076-3 DIN EN 60076-10 DIN EN 60076-1 DIN EN 60076-4 DIN EN 60076-11 + 3 more
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DAkkS D-PL-17438-01-04 Stuttgart, DE
IEC 60335-1: 2010 IEC 60335-2-2 IEC 60335-2-3 DIN EN 60335-2-3: 2002 IEC 60335-2-4 + 3 more
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ENAC LE147 Campanillas, ES
IEC 61730-2 IEC 61215-1-2 IEC 61215-2 IEC 61215-1-3 IEC 61215-1-4 + 3 more
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DAkkS D-K-21738-01-01 Köln, DE
- Gleichspannung Messgeräte > 330 mV > 3,3 V > 33 V > 330 V + 3 more
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UKAS 0138 Irlam, GB
Gas pressure (absolute) Gas pressure (gauge) Hydraulic pressure (gauge) Hydraulic Pressure (absolute) PRESSURE (cont’d) + 1 more
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DIAL

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DAkkS D-PL-17358-02-00 Lüdenscheid, DE
DIN 5032-1 DIN 5032-2 DIN 5032-4 DIN 5033-8 DIN 5036-3 + 3 more
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DIANOVIS

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DAkkS D-ML-21243-01-01 Gera, DE
Kleines Blutbild (maschinell) Differentialblutbild (maschinell) Thrombozyten Retikulozyten Natriumchlorid + 3 more
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COFRAC 1-6191 Grande Synthe, FR
NF EN ISO 6892-1 (méthode DIN EN 10164 ASTM E 8 ASTM A 370 DIN EN ISO 6508-1 + 3 more
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DAkkS D-K-15034-01-01 Gevelsberg, DE
Gleichspannung 10 mV Quellen > 100 mV > 1 V > 10 V > 100 V + 3 more
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DAkkS D-PL-11125-01-00 Nürnberg, DE
ASTM C 1166 IEC 60512-16-7 ID168 IEC 60512-16-9 AK gegen Sc1-70 + 3 more
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ENAC LE776 Madrid, ES
SM 5210 D UNE-EN ISO 27888 SM 5220 D SM 2130 B UNE-EN ISO 11885 + 3 more
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DAkkS D-ML-22411-01-00 Dresden, DE
Antikörper FILA-Klasse I Lymphozytäre Kreuzprobe E, -DRB1, -DQB1, -DPB1, DRB3/4/5, -DQA1, KIR MICA, MICB, CCR5832 + 3 more
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UKAS 0143 Letchworth Garden City, GB
LENGTH Blade type Straight edges Surface plates External micrometer + 3 more
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DAkkS D-PL-11035-01-02 Essen, DE
ID136 > 140 DIN EN 143 DIN EN ISO 21149 DIN EN 13274-1 + 3 more
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DAkkS D-ML-21979-01-00 Hamburg, DE
HLA-Typsierung (HLA-B*27) Azoospermiefaktor (AZFa/AZFb/AZFc) Chorea Huntington (HTT) OMIM# 143100 + 3 more
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DNKA

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UKAS 9730 Govan, GB
staining based on HSG 248. (PCM) based on HSG 248 (HSG 248) – 2021 QSOP 03 based on HSG 248 QSOP 01 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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