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 876–900 of 1,273 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
Robert Koch-Institut
Active
Salmonellen
Salmonella enterica, Shigellen, Yersinie
Shigellen
Salmonella sv. Paratyphi
Neisseria meningitidis, Listeria
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Charpy impact test (ISO 148-1)
Salt spray / neutral salt fog test (ISO
elektronische Waagen
1) In den CMC sind die erweiterten Messu
DIN EN ISO 12185
DIN EN ISO 3405
DIN EN 13016-1
DIN EN ISO 20884
DIN EN ISO 20846
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Spinocerebelläre Ataxien
Bindegewebserkrankungen: ACTA2, COL1A1,
HD; Chorea Huntington
(Huntingtin-Gen)
Dentatorubrale-Pallidoluysiane
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Rwanda Standards Board
Active
ISO 6222
AM09 based on BS ISO 21527-1:
ISO 6579-1
ISO 4832
ISO 2171
+ 3 more
S.E. CARBUROS METÁLICOS
Active
0,03 · 10-2 mol/mol C < 0,3 · 10-2 mol
0,3 · 10-2 mol/mol C 1,1 · 10-2 mol/
1,1 · 10-2 mol/mol ≤ C < 26 · 10-2 mol/m
1,1 · 10-2 mol/mol ≤ C < 26 · 10-2 mol/m
9 · 10-6 mol/mol C < 75 · 10-6 mol/mol
+ 3 more
Durchfluss von 2 m3/h bis 800 rn3/h
− Durchfluss von Flüssigkeiten
Volumendurchfluss
dV/dt von
strörnenden
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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
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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
(15 ± 1) ⋅ 10-6 mol/mol (1000 ± 50) ⋅ 10
(8 ± 0,5) ⋅ 10-2 mol/mol (1,4 ± 0,1) ⋅ 1
(3000 ± 150) ⋅ 10-6 mol/mol (9 ± 1) ⋅ 10
(80 ± 8) ⋅ 10-6 mol/mol
(100 ± 8) ⋅ 10-6 mol/mol
SEQUOPRO
Active
0,015 l/min ≤ Q ≤ 40 l/min
0,0 · 10-9 mol/mol
20 ⋅ 10-9 mol/mol ≤ C ≤ 500 ⋅ 10-9 mol/m
0,00 · 10-6 mol/mol
0,5 ⋅10-6 mol/mol ≤ C ≤ 10 ⋅10-6 mol/mol
+ 3 more
SCL
Active
DIN EN ISO 12966-2
DIN EN 12266-2
DIN EN ISO 12966-4
DIN EN 13656
DIN 30660
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1 mg 2 mg 5 mg 10 mg 20 mg 50 mg 100 mg
10 g 20 g 50 g 100 g 200 g 500 g 1 kg 2
.1 mg 2 mg 5 mg 10 mg 20 mg 50 mg 100 mg
CEM DI-021
CEM DI-004
CEM EL-007
CEM DI-003
CEM DI-008
+ 3 more
EURAMET CG-6
CEM DI-021
CEM DI-004
CEM DI-013
CEM DI-012
+ 3 more
SGS Germany
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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DIN 51757
ASTM D 4052
DIN EN ISO 12185
DIN EN ISO 3405
DIN EN 13016-1
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