Scope
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
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DIN EN ISO 11821
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BS EN ISO 11821
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NF EN ISO 11821
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UNI EN ISO 11821
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UNE EN ISO 11821
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NEN EN ISO 11821
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DIN EN ISO 3095
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BS EN ISO 3095
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NF EN ISO 3095
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UNI EN ISO 3095
🇪🇸
UNE EN ISO 3095
🇳🇱
NEN EN ISO 3095
1,516
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17
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Microtech Services (Wessex)
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ISO 7251
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ISO 6888-3
1) A:2b based on ISO 4833-2:2013 Amd 1:2
2) A:6c based on ISO 21528-1:2017 by mos
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Mimete Srl Unipersonale
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ASTM B212-21
ASTM E1019-24
ASTM B527-24
BS EN ISO 3923-1
ASTM B417-22
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Konventioneller
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Massenormale
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ETSI EN 319 412
ETSI EN 319 401
ETSI EN 319 411-2
ETSI EN 319 411-1
Ministry of Defence
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Specific Values
Specific values (continued)
ELECTRICAL
Other Values
AC CURRENT
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Mitutoyo Deutschland
Active
Parallelendmaße 0,5 mm
DIN EN ISO 3650:1999
Parallelendmaße
> 10 mm
Parallelendmaße > 100 mm
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Mobiler Kalibrierdienst Fini
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Gleichspannung 3 mV
Messgeräte 10 mV
> 100 mV
> 220 mV
> 11 V
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Temperatur 50 °C
Railway brake handbooks (UIC 547)
1) In den CMC sind die erweiterten Messu
Moorcroft Controls
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DC CURRENT
Gas pressure (gauge)
ELECTRICAL
DC VOLTAGE
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IEC 61000-4-2: 2008
VDE 0847-4-2
IEC 61000-4-3: 2006
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NATEC Sensors
Active
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− Durchfluss von Flüssigkeiten
Gleichspannung U
(Simulation des Signals
generators)
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NEMKO
Active
IEC 61000-4-2: 2008
IEC 61000-4-3: 2006
IEC 61000-4-4: 2012
IEC 61000-4-5: 2005
IEC 61000-4-6: 2013
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NORMEC QS
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NEN-EN 13361
ISO 13362
NEN-EN 13491
DIN EN 13493
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NSF Wales Limited
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BS EN ISO 7686:2005
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DIN ISO 10381-7
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Active
Elektrische Feldstärke /
2 V/m
2,5 V/m
1 V/m
Magnetische Feldstärke /
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