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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NBN EN ISO 11821
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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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NBN EN ISO 3095
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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
2,775
Accredited labs
21
Countries
Showing 76–100 of 829 labs
Audiology | Adult Hearing Services:
Audiology | Otoscopy
Audiology | History Taking
Audiology | Pure Tone Audiometry
Audiology | Impression Taking
+ 3 more
Plasmodium species
Venous whole blood: EDTA Blood film repo
Serum Total Protein | Colorimetric
Serum Detection of: | ** Documented in h
Formalin fixed tissue | Decalcification
+ 3 more
Audiology | Adult Hearing Services:
Audiology | Otoscopy
Audiology | History Taking
Audiology | Pure Tone Audiometry
Audiology | Impression Taking
+ 3 more
Serum | Detection of: bioMérieux VIDAS u
Venous Serum | Antibodies
Body fluids: Preparation and examination
Whole Blood | Ionised calcium
Whole Blood | Glucose
+ 3 more
Amniotic Fluid | Manual Extraction
Amniotic Fluid | Using:
Amniotic Fluid | DNA Genotek prepIT.L2P
Amniotic Fluid | SOPs:
Amniotic Fluid | LP 352 003 iGENatal
+ 3 more
Serum | ELISA technique
Whole Blood unless stated | Antibody scr
Whole Blood unless stated | SOP H-3090,
Whole Blood unless stated | SOP H-262
Whole Blood unless stated | Antibody Ide
+ 3 more
Serum | Detection of: bioMérieux VIDAS u
Faeces | SOP: MIC-UKHSA-CDRN-EP-1
Faeces | Campylobacter spp.
Faeces | Shigella spp.
CSF | Enterovirus
+ 3 more
Systemic body fluid samples | Tissue Tek
Cervical LBC Samples | Preparation of sa
Cervical cells in PreservCyt | 16, 18, 3
Cervical cells in PreservCyt | 45, 51, 5
Cervical cells in PreservCyt | 66, 68
+ 3 more
Blood | Tacrolimus
Blood | Sirolimus
HUMAN BODY FLUIDS | Automation Roche Cob
Serum | 760
Plasma/Serum | 3-Hydroxy Butyrate Photom
+ 3 more
DNA | SOP:-CYT ACQM 020
Serum | SOP: M-2252
Blood, buffy coat, spleen | SOP HI-1047
Blood, buffy coat, spleen | SOP HI-220 D
DNA | Nanodrop 2000C.
+ 3 more
CTD Panel: | • U1RNP (RNP70, A, C,)
screen: | • Human recombinant
Typing of ENA Specificities: | • Anti-Ro
Audiology | Adult Hearing Services:
Audiology | Otoscopy
Audiology | History Taking
Audiology | Pure Tone Audiometry
Audiology | Impression Taking
+ 3 more
Serum | By calculation:
Semen | Fertility testing: Based on WHO
Citrated plasma | Thrombin time
Citrated plasma | Factor assays: LP-COA-
Urine | Electrophoresis
+ 3 more
Birmingham City Council
Active
(HSG 264, 2012)
staining based on HSG 248
(PCM) based on HSG 248
(PCM) based on HSG 248)
(HSG 248) – 2021 )
Citrated plasma | (INR)
HUMAN BODY FLUIDS: Biochemistry examinat
Citrated plasma | (chromogenic)
Blood | Tacrolimus
Citrated Plasma | Assay
+ 3 more
Semen Post vasectomy: | Based on 2016 La
Volume | Colorimetric strips
AB Rh D Negative | SOP1565: ABO/ D group
O Rh D Negative | ABO/Rh (2D) + Kell car
O Rh D Negative | SOP40: Manual methods
+ 3 more
Megakaryocytes | CD61
Epstein Barr Virus | EBER
Neuroanatomical marker | Calretinin
Macrophages and mononuclear | CD68
Demonstration of synaptophysin | Synapto
+ 3 more
Semen Post vasectomy: | Based on 2016 La
Volume | Colorimetric strips
AB Rh D Negative | SOP1565: ABO/ D group
O Rh D Negative | ABO/Rh (2D) + Kell car
O Rh D Negative | SOP40: Manual methods
+ 3 more
Trust
Serum | I/S/T/160
Bloodspot Pterins | N/S/B/009
Plasma, Urine Amino Acids (Quantitative)
CSF | I/S/144
+ 3 more
Plasma | SOPs: MOL EXTR 015, 016
Bone Marrow | Separator
Bone Marrow | SOP: PP 02.01.95
Plasma | PP 03.01.21
Plasma | PP 03.01.13
+ 3 more
Bolton NHS Foundation Trust
Active
Plasmodium species
Quantification of: | Roche Cobas 8000 sy
TISSUES for the purpose of clinical diag
TISSUES for the purpose of clinical diag
TISSUES for the purpose of clinical diag
+ 3 more
Bolton NHS Foundation Trust
Active
Swabs from ear, pus, wounds, eye, Genera
Bodily fluids – joint aspirates, CSF, |
BAL, NBL, NPA, ETube | MB-INS-060 Readin
Bone | (Swabs/Sputa)
Faeces General isolation and | MB-ENT-SW
+ 3 more
Bolton NHS Foundation Trust
Active
Semen Post vasectomy: | Based on 2016 La
Semen Fertility testing: | Based on WHO
Volume | Volume/weight
Volume | Colorimetric strips
Amyloid | Congo Red
+ 3 more
(HSG 248) – 2021
(HSG 264:2012)
staining based on HSG 248
(PCM) based on HSG 248
Brain Sciences
Alzheimer’s disease: | Roche Cobas e801
No matching labs found.