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
1,273
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15
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Nuclear Restoration Services
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AIR KERMA RATE
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HBs-Antigen (Hepatitis B-Surface
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O.C. Consulting (UK)
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(HSG 264, 2012)
Appendix 5 of HSG 227 (2004)
(HSG 248) – 2021
(PCM) based on HSG 248
IEC 61400-23
ASTM G73 (2012)
IEC 60885-3, 2.4.1
IEC 60502-2
IEC 60840
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One Scientific
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ISO 6888-1
ISO 21528-2
BS ISO 4832:2006
ISO 4833-1
ISO 6579-1
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Optical Test & Calibration
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DC Resistance
DC CURRENT
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PHH Environmental (UK)
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HSG 227 (2004))
(HSG 264, 2012)
HSG 264 (2012) and Appx. 3 of
(HSG 248) – 2021
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Paragon Scientific
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Refractive Index
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Liquids
Density in Air at 20
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Particle Technology
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MIL-STD 810D, Method 510.2
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MIL-STD 810G:2008 Method 501.5
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MIL-STD-810H, Method 510.7
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Pennington Choices
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(HSG 264, 2012)
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(HSG 248) – 2021
(PCM) based on HSG 248
Manual based on HSG 248
Poulten Selfe and Lee
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TEMPERATURE
Viscosity constant ‘C’
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GEARS SPUR/HELICAL EXTERNAL (cont’d)
As for Involute Spline Gauges
ISO 6579-1
ISO 15213-2
ISO 11290-1
ISO 7932
F100 based on BS EN ISO
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Pullman Instruments (UK)
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DC CURRENT
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AC Current Generation
DC RESISTANCE (cont’d)
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(HSG 248) – 2021
(PCM) based on HSG 248
QSOP 03 based on HSG 248
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ÖNORM EN ISO 17637
BS EN ISO 15614-1:2017
ASTM A 370
DIN EN 10080
BS EN ISO 9015-1:2011
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Ramcare
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DC CURRENT
DC VOLTAGE
thermometer Pt100
ROTATIONAL SPEED
Generate
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