In July, more than over 200 researchers called for the world to take more precautions against the airborne transmission of COVID-19. WHO then published guidance on 9 July which referred to outbreak reports that suggested ‘the possibility of aerosol transmission’ of COVID-19 (https://is.gd/erayiq) and since then the weight of research has continued to grow.
In response to new evidence on airborne transmission and general recognition of long-range aerosol-based transmission of COVID-19, The Federation of European Heating, Ventilation and Air Conditioning Associations (REHVA) has updated its ‘REHVA COVID-19 Guidance Document’, published on 3 August 2020 (https://is.gd/nocile) citing ventilation as the principal engineering control to help control infection, thus giving further weight to the vital role ventilation plays, states Vent-Axia.
The REHVA guidance advises how to operate HVAC and other building service systems to prevent the spread of the COVID-19 in workplaces. Since the virus emerged the possibility of airborne transmission of COVID-19 has been considered, but as a novel virus it was important to gather evidence to prove this. The updated REHVA guidance states that new evidence on airborne transmission has developed recently: “This has made ventilation measures the most important engineering controls in the infection control.” It adds that although physical distancing is important to avoid close contact. It states: “the risk of aerosol concentration and cross infection from 1.5m onward from an infected person can be reduced with adequate ventilation and effective distribution solutions.”
REHVA guidance includes practical recommendations that can be applied to existing buildings at a relatively low cost to reduce the number of cross-infections indoors. Top of the list is: “Provide adequate ventilation of spaces with outdoor air” again cementing the importance of ventilation. Other ventilation guidance includes: switching ventilation on at nominal speed at least two hours before the building opening time, and set it to lower speed two hours after the building usage time; at nights and weekends, do not switch ventilation off, but keep systems running at a lower speed; and to open windows regularly (even with a mechanical ventilation system). In toilets where toilet plume aerosols pose a risk, the guidance advises keeping toilet ventilation in operation 24/7; avoiding open windows in toilets to maintain the right direction of ventilation; and instructing building occupants to flush toilets with closed lid.
Jenny Smith, head of Vent-Axia marketing, says: “At Vent-Axia we are here if businesses need advice on ventilation. A raft of global scientific evidence has confirmed aerosol transmission, making it a higher-risk to be inside a building than outside. With autumn on the horizon and more people going to work and school, we need to prepare now to ensure ventilation systems are working and providing adequate airflow. To help mitigate the risk of COVID-19 transmission inside a building or home, it is vital to increase airflow and ventilate effectively. Now is the time to check ventilation to ensure there is enough airflow to dilute the virus in the air and improve indoor air quality. Ventilating for longer and opting for ventilation with higher airflow volumes will help reduce the risk.”
Other advice from REHVA to help mitigate COVID-19 virus transmission includes switching AHUs with recirculation to 100% outdoor air; inspecting heat recovery equipment to be sure leakages are under control; adjusting fan coil settings to operate so that fans are continuously on; not changing heating, cooling and possible humidification setpoints; carrying out scheduled duct cleaning as normal; replacing central outdoor air and extract air filters as normal, according to the maintenance schedule; regular filter replacement and maintenance works to be performed with common protective measures including respiratory protection; introducing an indoor air quality sensor network that allows occupants and facility managers to monitor ventilation is operating adequately.
Vent-Axia has already supplied ventilation to a wide-range of essential projects, such as the Nightingale Hospital in London, and states that it is available to offer advice to businesses as they prepare to reopen. Notable products include its T-Series extract fan particularly popular, ACM inline fans, and its Sentinel Totus² Demand Energy Recovery Ventilation system (D-ERV).