ISO 11820:2019

In-Situ Sound Attenuation Measurement of Silencers

ISO 11820 specifies the in-situ measurement method for determining the acoustic attenuation performance of silencers installed in railway ventilation ducts, brake systems, and exhaust lines. This test is critical for validating noise control equipment on operating trains and stationary installations where laboratory testing is impractical. Railway manufacturers, maintenance operators, and acoustic engineers use these measurements to verify compliance with noise regulations and to optimize silencer design. Accreditation ensures that attenuation claims are reliable and that performance targets for noise reduction are consistently achieved in real-world applications.

What it measures

  • Sound pressure level reduction across silencer (dB)
  • Attenuation performance by frequency band
  • Insertion loss of silencer in situ
  • Acoustic performance under operating conditions
  • Noise transmission loss through silencer element
🇧🇪 NBN EN ISO 11821 🇩🇪 DIN EN ISO 11821 🇬🇧 BS EN ISO 11821 🇫🇷 NF EN ISO 11821 🇮🇹 UNI EN ISO 11821 🇪🇸 UNE EN ISO 11821 🇳🇱 NEN EN ISO 11821 🇧🇪 NBN EN ISO 3095 🇩🇪 DIN EN ISO 3095 🇬🇧 BS EN ISO 3095 🇫🇷 NF EN ISO 3095 🇮🇹 UNI EN ISO 3095
2,677 Accredited labs
20 Countries

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AGROLAB MEDIOAMBIENTE, S.L. (Unipersonal)

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ENAC LE2633 Tarragona, ES
Railway wheel-rail interaction — roughne ISO 5667-11 ISO 11423-1 ISO 5667-4 ISO 5667-10 + 3 more
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AGROLAB Umwelt

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DAkkS D-PL-22637-01-02 Kiel, DE
ISO 5985 DIN EN 12880 DIN EN ISO 19458 DIN EN 932-2 DIN EN ISO 17892-1 + 3 more
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AGROLAB Wasseranalytik

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DAkkS D-PL-22802-01-01 Eching am Ammersee, DE
ISO 21527-2 DIN EN ISO 18593 DIN EN ISO 19458 DIN ISO 16000-17 DIN EN ISO 10523 (C 5) + 3 more
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AGRUPA LABORATORIO, S.L.L.

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ENAC LE2360 Derio, ES
Railway passenger ride comfort evaluatio ISO 5667-11 ISO 5667-4 ISO 5667-10 ISO 15705 + 3 more
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AGÉNCIA CATALANA DE L´AIGUA

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ENAC LE2081 Abrera, ES
ISO 7150-1 ISO 15705 ISO 6878 ASTM E1077-14(2021) ISO 20595 + 3 more
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AIDIMME. INSTITUTO TECNOLÓGICO METALMECÁNICO, MUEBLE, MADERA, EMBALAJE Y AFINES

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ENAC LE027 Paterna, ES
ISO 3795 DIN EN 60529 IEC 60529: 1989 IEC 60068-2-1 IEC 60068-2-2 + 3 more
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AIP

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DAkkS D-K-21076-01-01 Haldenwang, DE
Railway brake — anti-slide device (UIC 5 Railway brake — magnetic track brakes (U Railway brakes — conditions for homologa Railway brakes — electropneumatic brakes Railway braking — urban guided transport + 3 more
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AIR CONTROLE

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COFRAC 1-6250 Decize, FR
NF X 43-050 NF X 43-269 ISO 16000-7 FD X 46-033
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AIR PRODUCTS

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BELAC 674-CAL Sombreffe, BE
Helium Nitrogen Toluene/Hexane CARBON DIOXIDE Serum | (Diphenylmethane + 3 more
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AIRALYZ

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COFRAC 1-6339 Croissy-Sur-Seine, FR
NF X 43-050 NF X 43-269 ISO 16000-7 FD X 46-033
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AIRGRUP

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ENAC LC10.235 Rinconada, ES
Tensile testing of metallic materials (I ASTM E 8 ISO 6507-1 BS EN ISO 9015-1:2011 BS EN ISO 9015-2 + 3 more
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AIRMETRIE - Agence Nord

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COFRAC 1-1617 Dechy, FR
DIN EN 13126-19 ISO 10780 DIN EN ISO 16911-1 DIN EN 13284-1 DIN EN 14790 + 3 more
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AIRTHEMIS SUD EST

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COFRAC 1-7447 Venelles, FR
ISO NF X 43-257 NF X 43-050 NF X 43-269 ISO 16000-7 + 1 more
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AISICO

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ACCREDIA 00378 Pereto, IT
DIN EN ISO 6508-1 DIN EN 1793-1 DIN EN 1793-2 DIN EN 1793-4 DIN EN 1793-5 + 3 more
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AKL Messtechnik

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DAkkS D-K-18095-01-00 Karlsfeld, DE
- Wechselstromstärke Quellen Widerstände / Messgeräte > 100 V + 3 more
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AKS Aqua-Kommunal-Service

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DAkkS D-PL-14191-01-01 Frankfurt (Oder), DE
DIN EN 12880 DIN EN ISO 19458 DIN EN ISO 11885 DIN EN ISO 10523 (C 5) DIN EN 27888 (C 8) + 3 more
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AKUVIB Engineering and Testing

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DAkkS D-PL-11133-01-01 Bochum, DE
Sound power level determination — genera Sound power — engineering methods for sm Sound power — in-situ using reference so Sound intensity — scanning method (ISO 9 Occupational noise exposure measurement + 3 more
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AL-PRO

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DAkkS D-PL-11316-01-00 Großheide, DE
DIN ISO 9613-2 * IEC 61400-12-1 * IEC 61400-12-5 * IEC 61400-50 * IEC 61400-50-1 * + 2 more
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ALBO-tec Technologiezentrum für Analytik und Bodenmechanik

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DAkkS D-PL-14529-01-03 Mülheim an der Ruhr, DE
DIN EN 12879 DIN EN 12880 DIN EN 27888 (C 8) DIN EN ISO 11885 (E 22) DIN EN ISO 5667-3 (A 21) + 3 more
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ALDARIM

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COFRAC 1-6043 Sainte Helene Du Lac, FR
NF X 43-050 NF X 43-269 NF X43-050 (parties utiles de ISO 16000-7 FD X 46-033
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ALFADIR - ARIA

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COFRAC 1-6425 Bagnols Sur Ceze, FR
NF X 43-257 NF X 43-050 NF X 43-269 ISO 16000-7 FD X 46-033
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ALIANIS

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COFRAC 1-6842 Beynes, FR
NF X 43-050 NF X 43-269 ISO 16000-7 FD X 46-033
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ALS

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COFRAC 1-5853 Saint-Pierre-De-Chandieu, FR
ISO 22262-1 NF X 43-257 NF X 43-050 NF X 43-269 NF X43-050 (parties utiles de + 2 more
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ALS Analytik Labor Schirmacher

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DAkkS D-PL-14594-01-01 Hamburg, DE
DIN EN 12879 DIN EN 12880 DIN EN ISO 17892-4 DIN 18123 DIN EN ISO 11885 + 3 more
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ALS France

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COFRAC 1-1364 Saint-Quentin-Fallavier, FR
DIN EN 27888 DIN ISO 16000-3 DIN ISO 16000-6 DIN EN ISO 16000-9 DIN EN ISO 11885 + 3 more
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Industries

Railway rolling stock manufacturing Train maintenance and depot operations Acoustic engineering and noise control HVAC and ventilation system design Brake system suppliers and integrators

Related Standards

  • ISO 11821 Acoustics — In-situ measurement of sound insulation of windows and façades
  • EN ISO 3095 Acoustics — Measurement of noise emitted by railbound vehicles
  • ISO 7235 Acoustics — Laboratory measurement of sound absorption coefficient of materials in impedance tubes

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