Ventilation effectiveness in classroom infection risk control

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dc.contributorAalto-yliopistofi
dc.contributorAalto Universityen
dc.contributor.authorKiil, Martinen_US
dc.contributor.authorValgma, Indreken_US
dc.contributor.authorVõsa, Karl Villemen_US
dc.contributor.authorSimson, Raimoen_US
dc.contributor.authorMikola, Aloen_US
dc.contributor.authorTark, Teeten_US
dc.contributor.authorKurnitski, Jareken_US
dc.contributor.departmentDepartment of Civil Engineeringen
dc.contributor.groupauthorPerformance in Building Design and Constructionen
dc.contributor.organizationTallinn University of Technologyen_US
dc.date.accessioned2023-08-16T06:19:32Z
dc.date.available2023-08-16T06:19:32Z
dc.date.issued2023-06-16en_US
dc.description| openaire: EC/H2020/856602/EU//FINEST TWINS Publisher Copyright: © The Authors, published by EDP Sciences, 2023.
dc.description.abstractThe benefits of a good ventilation in classrooms are a well-studied topic regarding health and learning outcomes. However, many studies still show poor results regarding air quality, air change rate and air velocities. In this paper, typical Estonian classroom air distribution solutions were studied in an air distribution laboratory at Tallinn University of Technology. The air change efficiency was measured with CO2 tracer gas concentration decay method. For determining the contaminant removal effectiveness, continuous dose method was used to create a constant contaminant source. In addition, by using air velocity probes, we conducted draught measurements in the mock-up classroom. Tests were conducted using dedicated room-based air handling unit and thermal mannequins for imitating heat sources from students. We found that all solutions studied ensured the air change efficiency roughly corresponding to fully mixing air distribution, but local ventilation effectiveness values of contaminant removal showed large variation from 0.6 to 1.7 stressing the impact of source location. Grouped ceiling supply circular diffusers and single vertical supply grille air distribution commonly used in renovated educational buildings resulted in higher draught risk on the border of the occupied zone. High air velocities recorded in some areas of the classroom perimeter, well explain why draught is considered as one of the main reasons why the airflow rates are reduced, or supply air temperatures are lifted compared to designed values. Perforated duct diffusers resulted in acceptable air velocities. In conclusion, local ventilation effectiveness of contaminant removal showed that fully mixing is not a case with a point source, although air change efficiency determined with equally distributed source showed fully mixing conditions. Therefore, in those cases, the air change rate should be increased to achieve the same ventilation effectiveness. Based on the experiments conducted, a point source ventilation effectiveness measurement method for the breathing zone is proposed. This value determined at least with two source locations can be used in infection risk-based ventilation design.en
dc.description.versionPeer revieweden
dc.format.extent8
dc.format.mimetypeapplication/pdfen_US
dc.identifier.citationKiil, M, Valgma, I, Võsa, K V, Simson, R, Mikola, A, Tark, T & Kurnitski, J 2023, ' Ventilation effectiveness in classroom infection risk control ', E3S Web of Conferences, vol. 396, 01043 . https://doi.org/10.1051/e3sconf/202339601043en
dc.identifier.doi10.1051/e3sconf/202339601043en_US
dc.identifier.issn2555-0403
dc.identifier.otherPURE UUID: 1194a34d-091c-4c06-a540-d88787dea66fen_US
dc.identifier.otherPURE ITEMURL: https://research.aalto.fi/en/publications/1194a34d-091c-4c06-a540-d88787dea66fen_US
dc.identifier.otherPURE LINK: http://www.scopus.com/inward/record.url?scp=85164521956&partnerID=8YFLogxKen_US
dc.identifier.otherPURE FILEURL: https://research.aalto.fi/files/118576083/e3sconf_iaqvec2023_01043.pdfen_US
dc.identifier.urihttps://aaltodoc.aalto.fi/handle/123456789/122436
dc.identifier.urnURN:NBN:fi:aalto-202308164786
dc.language.isoenen
dc.publisherEDP Sciences
dc.relationinfo:eu-repo/grantAgreement/EC/H2020/856602/EU//FINEST TWINS Publisher Copyright: © The Authors, published by EDP Sciences, 2023.en_US
dc.relation.ispartofseriesE3S Web of Conferencesen
dc.relation.ispartofseriesVolume 396en
dc.rightsopenAccessen
dc.subject.keywordAir velocityen_US
dc.subject.keywordClassroomen_US
dc.subject.keywordVentilation effectivenessen_US
dc.titleVentilation effectiveness in classroom infection risk controlen
dc.typeA4 Artikkeli konferenssijulkaisussafi
dc.type.versionpublishedVersion
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