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
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UNE EN ISO 3095
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NEN EN ISO 3095
1,516
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Testo Industrial Services
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RELATIVE HUMIDITY
HUMIDITY continued
loggers
Gas Pressure Gauge
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Tetra Tech Consulting
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(HSG 248) – 2021
RPSCA1 based on HSG 248
(PCM) based on HSG 248
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BS 7592:2008, BS 8554:2015
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DC Resistance
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DC VOLTAGE
CAPACITANCE
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(HSG 248) – 2021
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QOP01 based on HSG 248
(PCM) based on HSG 248
The Original Gauge Company
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LENGTH
Screw ring gauges (parallel)
LENGTH cont.
As for Involute Spline Gauges
See Note 2
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The Testing Lab
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DIN EN 933-11
BS EN ISO 17892-1:2014+A1:2022
BS EN ISO 17892-10:2018
BS EN ISO 17892-11:2019
BS EN ISO 17892-2:2014
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Thomas Dudley
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BS 1212-2:1990 Clause 4
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DIN EN 997
Laktoseintoleranz (LCT -14055
BS 1212-4:1991 Clause 4, 13, 14
Total Clean Air
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DIN EN 12469
BS EN ISO 14644-1:2015
BS EN ISO 14644-4:2022
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Tru-Cal Metrology
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including dial and digital
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ANCILLARY MEASUREMENTS
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Tyneside Standards
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Micrometers
See Notes 3 and 5
See Note 6
Caliper
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FNED142 BS EN ISO 11816-
FNES67 (P1) based on BS EN ISO
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FNES16 (F13) based on BS EN
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UL International (UK)
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DIN EN 12209
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guides HSG 264 (2012) and
ACoP L8 and BS 8580-1:2019
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DIN EN 13284-1
BS EN ISO 23210:2009
requirements of BS EN 14181:2014
IEC 60519-11
requirements of BS EN
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