Planning ventilation in times of Corona
With the Corona pandemic, the requirements for the ventilation of rooms have also increased significantly. With increasing knowledge about the spread of the viruses, ventilation has become the focus of attention, especially in office buildings, schools, day-care centres and other buildings where there are frequent gatherings of people. In order to significantly reduce the risk of infection in these rooms, correct ventilation behaviour and regular air exchange are essential. But how can ventilation be planned correctly in times of Corona?
Aerosols as the main transmission route of the coronavirus
By now, most people are well aware that the greatest risk of infection is through the air. Aerosols, as particles suspended in the air, enter people's respiratory tract. If these aerosols contain viruses, the risk of infection is high. For this reason, it is important to reduce the aerosol load in the air, which is only possible through regular air exchange. The longer the aerosols remain in the air, the higher the risk of transmission.
Various factors influence the aerosol load in the air:
- Volume at which singing / speaking takes place
- Number of people in the room
- Room size
What are aerosols?
Many are familiar with the term, but only a few have a concrete idea in their heads of what aerosols actually are. Aerosols are mixtures of solid and liquid particles that are created in the air when breathing, speaking, coughing or sneezing. Viruses can also be contained in these particles. Aerosols suspended in the air can easily be transmitted from one person to another through the respiratory tract. No direct contact is needed for this.
Regular ventilation to avoid risks
Regularly ventilating a room contributes significantly to aerosols escaping from the room air to the outside, thus considerably reducing the risk of infection. But what does "proper ventilation" actually mean and how often and how long should doors and windows be open to reduce the risk of infection? A distinction is made here between forced or cross-ventilation and technical ventilation.
Shock and cross-ventilation for exchanging room air
In the case of forced ventilation, all windows and doors are opened wide for 5 to 10 minutes at a time so that old air can escape and new, fresh air can enter a room. How often such shock ventilation should take place depends on various factors such as the size of the room and the number of people in it. If you want to be precise, you can use the CO2 timer of the statutory accident insurance, which determines the required ventilation intervals depending on these factors. Shock or cross-ventilation is a way of exchanging all the air in the room within a short period of time and minimising the energy losses that occur, for example, through tilted windows.
Technical ventilation in a building
As an alternative or supplement to shock ventilation, room air conditioning systems can also be installed in a room or building that continuously blow in filtered fresh air. In addition, the fresh air can be simultaneously heated or dehumidified, for example, to create an optimal and pleasant indoor climate.
Weather challenge with the right ventilation
Simply opening the window regularly to ensure a regular exchange of air: at least in the warm season and in good weather, this is not an impossible task. But what if it is storming, snowing, hailing or thundering outside and the very thought of opening the window now gives you goose bumps? A construction site outside the window of the school building can also be a considerable disruptive factor when the window has to be open on a regular basis.
This is where modern ventilation systems can be a real alternative. These systems are able to draw in fresh air from outside and transport it into the interior. At the same time, they ensure that stale air gets outside. In this way, a continuous exchange of air can be ensured, regardless of the weather.
Ventilation systems with heat recovery for a pleasant indoor climate
Proper ventilation in times of Corona and a pleasant indoor climate do not have to be mutually exclusive. Ventilation systems with heat recovery work energy-efficiently and achieve a very high degree of heat recovery. Here, the ventilation units are installed in pairs in the room and alternate in supply and extract air mode. This not only ensures clean room air and creates a pleasant room climate, but also ensures energy-efficient operation. In addition, further filters can be installed that also filter out odours or fine dust from the air.
Do ventilation systems completely replace room ventilation?
In order for ventilation systems to work efficiently and significantly reduce aerosol pollution, important rules must be considered. The operation should not be set to recirculated air, but completely to outside air. In addition, filters should be changed regularly and cleaning intervals shortened.
Even if the ventilation systems work efficiently and noticeably reduce the virus load, you should still ventilate regularly as a support, if possible. Even the best technical systems and despite regular shock ventilation, it is not possible to turn a room into a completely virus-free environment. Therefore, further hygiene and distance rules should always be observed.
Conclusion: Proper ventilation can significantly reduce the risk of infection
A combination of intermittent ventilation and the installation of modern ventilation systems achieves a consistent exchange of air throughout the day. This can noticeably reduce the virus load in a room and thus also considerably reduce the risk of infection. A major advantage is that the systems can also improve the indoor climate by continuing to use heat and by using good filters to prevent odours or fine dust from entering the room air in the first place.