The Role of Air Conditioning in the Diffusion of Sars-CoV-2 in Indoor Environments: a First Computational Fluid Dynamic Model, based on Investigations performed at the Vatican State Children’s Hospital © 2020 Elsevier Inc. All rights reserved.
More than 60 million people worldwide are affected by the Sars-Cov-2 infection, which already caused 1.500.000 deaths. This virus is mainly transmitted through exhalations from the airways of infected persons, so that Heating, Ventilation and Air Conditioning (HVAC) systems might play a role in increasing or reducing the spreading of the infection in indoor environments.
It has been modelled the role of HVAC systems in the diffusion of the contagion through Computational Fluid Dynamics (CFD) simulations of cough at the “Bambino Gesù” Vatican State Children’s Hospital.
Both waiting and hospital rooms were modeled as indoor scenarios. A specific Infection-Index (η) parameter was used to estimate the amount of contaminated air inhaled by each person present in the simulated indoor scenarios.
Study Conclusions
The study shows that HVAC system in a closed waiting room generates a marked space diffusion of droplets from a cough event. Although the doubling of HVAC’s air flow allows for a marked reduction in the airborn contaminant concentration this also leads to a substantial increase of turbulent air motions resulting in an increased and faster long-range spreading of droplets and air contaminants in the room. In indoor environment, the doubling of the air conditioned flow allows a relevant (up to 77%) reduction in droplets mass concentration within the room compared to nominal air flow. In the first 5 seconds from the cough event, no particular differences in droplets concentration are detectable in the room, while the relevant differences occur within 25 seconds due to the air conditioned systems that induce droplets air dispersion. In absence of air conditioning, larger particles more easily settle on the ground, while for nominal or doulbe-flow HVAC air-flow even the largest particles are subjected to turbulent phenomena and follow the air conditioned flow remaining suspended for longer time (see Scenarios A, B and C here below). Despite that, the calculation of Infection Index for all the subjects in the room proved that a higher air exchange allows to reduce in the long term the overall amount of inhaled contaminated air.
Infection risks & mitigation
CIBSE advise for safe working area’s
To minimise the risks of airborne transmission of SARS-CoV2 / COVD-19 the general CIBSE (The Chartered Institution of Building Services Engineers London - https://www.cibse.org/coronavirus) advice is to increase air supply and exhaust ventilation, supplying as much outside air as is reasonably possible. The underlying principle is to dilute and remove airborne pathogens.
The Coronavirus has spread fast and seriously affected our lives and businesses worldwide but in spite of the fact that Italy is one of the countries where this virus has hit hardest, Comefri SpA has kept going, kept producing and kept supplying our fans where they are needed.
We are proud to say that the Comefri Group is making a significant contribution to the war against this pandemic.
In fact, our fans have recently been installed in a large number of hospitals, which have been built or converted in record time to help cure Covid-19 patients around the world.
MCE 2020 was posponed to September 2020.
Comefri SpA is participating to the 2020 MCE Mostra Convegno Expocomfort in Milan, 17-20 March 2020.
Visit us at Hall 9 - Booth R23
MCE 2020: THE ESSENCE OF COMFORT
MCE symbolizes the fullest synthesis of housing comfort in the future. Essence lies at its core and represents the soul of living pleasure.
MCE website.
Comefri is pleased to announce the completion of n.4 Atex Axial Fans Φ900mm in A316L and blades in Aluminum with Heresite coating. The final use is in the Oil&Gas industrial sector.
Once again, Comefri consolidates its presence in the Oil&Gas sector by widening the supplies with its own Axial Fans.
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