Risk of Microbial Growth in Ventilation Ductwork Located in the Humid and Cold Conditions

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A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
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Buildings, Volume 13, issue 7
High humidity inside ductworks could be a potential risk for microbial growth and there is also a hypothesis that lower night-time ventilation increases the risk of growth. This study investigates the possibility of microbial growth in ventilation ductwork exposed to humid and cold conditions. Two different typical night-time ventilation strategies for public buildings were investigated: ventilation rate was either continuously the same (0.15 L/s, m2) or no airflow during the night-time. Experimental data were collected over a four-month period. In the experiment, microbial media was released inside the ductwork initially. During the test period, air temperature and relative humidity inside the ductwork were controlled between 11–14 °C and 70–90%. Wipe, swab and air samples were taken at the beginning, monthly and at the end of the test period. The study results showed the extinction of colonies by the end of the experiment regardless of the chosen night-time ventilation strategy. The colony count in the air was low throughout the study period. Therefore, the results indicate that the long-term growth on the walls of air ducts is unlikely and the risk of microbial transfer from the air ductworks to room space is low.
Funding Information: The authors acknowledge the Finnish Work Environment Fund, the Aalto University Campus & Real Estate (ACRE), the Senate Properties and the cities of Helsinki, Espoo and Vantaa, for the financial support. Publisher Copyright: © 2023 by the authors.
air quality, ductwork mold growth, night-time ventilation, Nordic climate, public buildings, ventilation microbial pollution
Kravchenko , I , Pasanen , P , Lestinen , S , Kilpeläinen , S & Kosonen , R 2023 , ' Risk of Microbial Growth in Ventilation Ductwork Located in the Humid and Cold Conditions ' , Buildings , vol. 13 , no. 7 , 1683 . https://doi.org/10.3390/buildings13071683