Be it offices, administration buildings and event locations, restaurants, cinemas, theatres, department stores, shops, supermarkets, leisure facilities or industrial sites: wherever people spend longer amounts of time, ventilation and air-conditioning installations ensure a constant, pleasant flow of air that people perceive as ‘fresh’. This involves maintaining temperatures that are adjusted to suit the current requirements and an appropriate level of humidity. In technical terms, we talk of ‘Thermal Comfort’ and ‘Indoor Environment Quality’ (IEQ), which are dependent on a number of factors.
Adequate indoor air quality can also be achieved by opening the windows – at least intermittently. But this can have significant limitations and can impact negatively on the occupants’ sense of wellbeing and on air quality. The ingress of warm air in summer overheats rooms and, in winter, cold external air cools them down too much. At the same time, the room air becomes extremely dry, which impacts on the body’s mucus membranes and increases the risk of infection from bacteria and viruses. No such problems arise when a ventilation system is in operation: these systems duct constantly filtered, warmed or cooled external air into the rooms and, at the same time remove contaminated air. This means that all-year-round, good indoor air quality can only be achieved through the use of a mechanical ventilation unit.
Experts agree that ventilation and air-conditioning technology will play a major role in the continuing Covid pandemic and in protecting occupants of indoor spaces from being infected by the coronavirus. “Ventilation units have an important part to play, because continual flushing of indoor spaces with high volumes of external air significantly dilutes the concentration of Covid aerosols in room air and thus greatly limits the risk of infection,” says Günther Mertz, Managing Director of the Association of Air Conditioning and Ventilation in Buildings (FGK). In effect: the more external air, the better the result. And, if the existing ventilation system is not able to provide sufficient external air to significantly reduce the amount of Covid aerosols, then two further measures can help:
On the one hand, windows can also be opened on a regular basis to create ventilation. And, on the other, supplementary air-purifying units can be set up in individual rooms. These units constantly suck in room air, filter out any viruses that it might contain in high-efficiency (generally up to at least 99 percent) particulate filters and then return the purified air to the room. Devices like this, which are also recommended by virologists, are now available from many manufacturers in a variety of designs and airflow levels. They are suitable to provide effective supplementary protection from coronavirus infection in, for example, classrooms, open-plan offices and conference rooms, as well as in doctors’ surgeries and fitness rooms.
At the same time, we can assume that the coronavirus epidemic, and the need to protect people from it, is set to be given greater consideration in the planning and installation of new ventilation and air-conditioning systems.
Podcast on the importance of fresh air
"Air is an essential part of life - just like food." In the Building Technology podcast, Prof. Dr. Christoph Kaup tells us how pollutants in the indoor air can be reduced as much as possible.