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
Accredited labs
17
Countries
Showing 226–250 of 345 labs
Nature’s Consultancy
Active
(HSG 248) – 2021
(PCM) based on HSG 248
DOC/002 based on HSG 248)
Normec DETS
Active
BS 1377: Part 2: 1990
DIN EN 12457
No DETSC 5012 based on BS EN
staining based on HSG 248.
(HSG 248) – 2021
+ 1 more
North Star Environmental
Active
(HSG 248) – 2021
NSDOC 47 based on HSG 248
staining based on HSG 248.
(PCM) based on HSG 248
Not One Iota
Active
(HSG 248) – 2021
SOP-12, based on HSG 248
staining based on HSG 248
(PCM) based on HSG 248
Nuclear Restoration Services
Active
AIR KERMA RATE
AMBIENT DOSE
HBs-Antigen (Hepatitis B-Surface
RESPONSE:
PERSONEL DOSE
O.C. Consulting (UK)
Active
(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
+ 3 more
One Scientific
Active
ISO 6888-1
ISO 21528-2
BS ISO 4832:2006
ISO 4833-1
ISO 6579-1
+ 3 more
Optical Test & Calibration
Active
DC Resistance
DC CURRENT
DC VOLTAGE
DC RESISTANCE (cont’d)
PHH Environmental (UK)
Active
HSG 227 (2004))
(HSG 264, 2012)
HSG 264 (2012) and Appx. 3 of
(HSG 248) – 2021
(PCM) based on HSG 248
Paragon Scientific
Active
Refractive Index
Capillary Viscometer Calibration
2.92 mm systems (continued)
Liquids
Density in Air at 20
+ 3 more
Particle Technology
Active
MIL-STD 810D, Method 510.2
MIL-STD 810E, Method 510.3
MIL-STD 810G:2008 Method 501.5
MIL-STD 810F, Method 510.4
MIL-STD-810H, Method 510.7
+ 3 more
Pennington Choices
Active
(HSG 264, 2012)
and Appx. 3 of HSG 227 (2004))
Executive guides HSG 264 (2012)
Perry Analytical
Active
(HSG 248) – 2021
(PCM) based on HSG 248
Manual based on HSG 248
Poulten Selfe and Lee
Active
TEMPERATURE
Viscosity constant ‘C’
Reference viscometers:
ASTM D4052 (Digital density
External (Tip) Diameter
Helix (lead) total deviation (F
GEARS SPUR/HELICAL EXTERNAL (cont’d)
As for Involute Spline Gauges
No matching labs found.