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
🇩🇪 DIN EN ISO 11821 🇬🇧 BS EN ISO 11821 🇫🇷 NF EN ISO 11821 🇮🇹 UNI EN ISO 11821 🇪🇸 UNE EN ISO 11821 🇳🇱 NEN EN ISO 11821 🇩🇪 DIN EN ISO 3095 🇬🇧 BS EN ISO 3095 🇫🇷 NF EN ISO 3095 🇮🇹 UNI EN ISO 3095 🇪🇸 UNE EN ISO 3095 🇳🇱 NEN EN ISO 3095
1,516 Accredited labs
17 Countries

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COFRAC 1-1761 Saint Etienne, FR
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COFRAC 1-5967 Saint-Gregoire Cedex, FR
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COFRAC 1-5835 Gasny, FR
DIN EN 27888 NF X 31-615 (Uniquement DIN EN ISO 10523
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NF X 43-050 NF X 43-269 - Annexe K NF X43-050 (parties utiles de
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COFRAC 1-6752 Ivry Sur Seine, FR
NF X43-050 (parties utiles de la NF X 43-050 NF ISO 22262-1 (parties utiles
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DIN EN 13346 CEN / TS 14235 NF T 90-412 DIN EN ISO 7899-1 DIN EN 12880 + 3 more
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DIN EN ISO 17294-2 DIN EN ISO 14403-2 DIN EN ISO 10304-1 NF-T 90-101 NF T90-015-1 + 3 more
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COFRAC 1-1466 Pessac Cedex, FR
NF V08-106 NF T 90-412 NF EN ISO 7887 – VDE 414-9-11 DIN EN ISO 7899-1 + 3 more
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COFRAC 1-0551 Laon Cedex, FR
DIN ISO 11466 NF X31-120 DIN EN ISO 11885 NF X31-147 DIN EN 16175-1 + 3 more
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COFRAC 1-1046 Les Ponts De Ce, FR
NF V08-401 DIN EN ISO 6888-2 DIN ISO 16649-2 BS ISO 15214:1998 NF V08-409 + 3 more
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COFRAC 1-1105 Serres-Castet, FR
DIN EN 10002-1 ASTM E8/E 8M ASTM A 370 NF EN ISO 6892-1 (méthodes A1, A2 et DIN EN 2002-001 + 3 more
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COFRAC 1-1021 Saint Beauzire, FR
ISO 14698-1 DIN EN ISO 17141 DIN EN 12469 DIN EN ISO 11138-2 DIN EN ISO 11737-2 + 3 more
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COFRAC 1-6990 La Ciotat, FR
DIN EN 13624 DIN EN 13727 DIN EN ISO 11930 DIN EN 17387 DIN EN ISO 22717 + 3 more
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COFRAC 1-1979 Limoges, FR
NF V 04-407 DIN EN ISO 6888-1 NF V04-403 0.95) based on BS ISO 21527-2:2008 DIN EN ISO 6888-2 + 3 more
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DIN EN 10002-1 BS ISO 9227:2022 DIN EN ISO 643 EN ISO 12624 DIN EN 10045-1 + 3 more
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COFRAC 1-7045 Sete, FR
NF X 43-050 (parties utiles NF X 43-269 NF X 43-050
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COFRAC 1-1734 La Capelle, FR
DIN EN ISO 8968-1 DIN 19662 DIN EN ISO 5534 DIN EN ISO 8968-4 DIN EN ISO 5764 + 3 more
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COFRAC 1-1290 Marseille Cedex 13, FR
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COFRAC 1-2193 Bourg-En-Bresse Cedex 9, FR
DIN EN ISO 17604 NF V08-401 0.95) based on BS ISO 21527-2:2008 DIN EN ISO 6888-2 DIN ISO 16649-2 + 3 more
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COFRAC 1-2350 Villepinte, FR
NF X 43-269 DIN 51750-3 NF X 46-032 NF EN 15934 – NF X 43-269 – Annexe K + 3 more
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COFRAC 1-0053 Gonfreville L'Orcher, FR
NF EN ISO 6892-1 Méthode B DIN EN ISO 6508-1 ISO 4969 DIN EN 10002-1 DIN EN ISO 643 + 3 more
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COFRAC 1-0600 Annecy, FR
NF T 90-412 DIN EN ISO 7899-1 DIN EN ISO 10304-1 DIN EN ISO 6888-2 DIN ISO 16649-2 + 3 more
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COFRAC 1-0606 Trappes Cedex, FR
DIN EN ISO 2505 ISO 18553 AMD 1 DIN EN 12099 ISO 13480 ISO 6964 + 3 more
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COFRAC 1-1531 Venissieux, FR
ISO 15202-3 NF X43-551 NF X 43-317 NF X 43-294 (juin DIN EN ISO 16017-2 + 3 more
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COFRAC 1-1140 Dammarie Les Lys, FR
NF EN ISO 19340 DIN EN ISO 10304-1 DIN EN ISO 15061 ISO 5815-1 NF T 90-117 + 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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