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
Accredited labs
15
Countries
Showing 226–250 of 299 labs
Rhopoint Metrology
Active
(Steel and tungsten carbide)
LENGTH (cont’d)
pneumatic tyres (See Note 1)
LENGTH (cont.)
Plain plug gauges (taper)
+ 3 more
Richard L Thomas Associates
Active
(HSG 264, 2012)
HSG 264 (2012) and Appx. 3 of
HSG 227 (2004))
Appendix 5 of HSG 227 (2004))
(HSG 248) – 2021
OP11 based on HSG 248
(PCM) based on HSG 248
OP04 based on HSG 248
SARIA
Active
AM-01 based on BS 4401:Part 1:
AM-32 based on BS 4401:Part 4:
AM-03 based on BS ISO 937:2023
AM-04 based on BS ISO
AM-31 based on BS EN ISO
+ 3 more
SATRA Technology Centre
Active
ISO 4931:1986 (withdrawn)
ISO 3759:1984 (withdrawn)
DIN EN 13759
DIN EN 12150-1
DIN EN ISO 15797
+ 3 more
SGS United Kingdom
Active
Joint IP/ASTM methods marked
IP 195*ASTM D1078
ASTM D847 by titration
ASTM D848
ASTM D 1353
+ 3 more
SGS United Kingdom
Active
(HSG 248) – 2021
ASB/SOP/OM8 based on HSG 248
(PCM) based on HSG 248
SGS United Kingdom
Active
CHEM014 based on BS 4401
based on BS 4401 Part 4:1970
CHEM018 based on BS 4401
CHEM023 based on BS 4401-
ISO 6579-1
+ 3 more
SGS United Kingdom
Active
Method CBG-M-SOP-027 based on BS EN ISO
AM01 based on BS EN ISO 4833-1:
2) Method CBG-M-SOP-038 based on BS ISO
ISO 10272-2
Method CBG-M-SOP-007 based on BS EN ISO
+ 3 more
SGS United Kingdom
Active
MPV Thrombozytenvolume
Gas meters
Power meter method
LENGTH
Waterdraw Method
+ 3 more
SGS United Kingdom
Active
BS EN 286 - Simple unfired pressure
BS EN 13445 Unfired pressure
BS EN13480 Metallic industrial
BS EN 12953 Shell boilers
BS EN BS EN 12952 Water-tube
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SOCOTEC Asbestos
Active
(HSG 248) – 2021
SCI/ASB/003 based on HSG 248
(PCM) based on HSG 248
SCI/ASB/001 based on HSG 248
Safety Advice Centre
Active
M002based on HSG 248
(HSG 248) – 2021
(PCM) based on HSG 248
Scientific Services
Active
(HSG 248) – 2021
D3TA2 based on HSG 248
(PCM) based on HSG 248
D3TA8 based on HSG 248
Scopus Asbestos Compliance
Active
(HSG 248) – 2021
SAC-SOP-15 based on HSG 248
SAC-SOP-07 based on HSG 248
staining based on HSG 248
SembCorp Utilities (UK)
Active
(HSG 248) – 2021
DI/AN/ME/025 based on HSG 248
DI/AN/ME/001 based on HSG 248
DI/AN/ME/026 based on HSG 248
(PCM) based on HSG 248
ServiceCal
Active
PRESSURE (cont’d)
DC CURRENT
DC VOLTAGE
CFH-Gen, Macula-Degeneration
Measurement
+ 3 more
LENGTH
Plain plug gauges (parallel)
Internal
Caliper
LENGTH (cont’d)
+ 3 more
Shirley Technologies
Active
ASTM E 2149-20
BS EN ISO 20743:2021 Section
ISO 14119
BS EN ISO 20645:2004
BS 1425-1:1991 Appendix A
+ 3 more
No matching labs found.