Did you know that ventilation can help us fight the coronavirus?
According to the newest analysis prepared by REHVA How to operate and use building services in order to prevent the spread of the coronavirus disease (COVID-19) virus (SARS-CoV-2) in workplaces, building users may be exposed to the virus infection spread by small particles that stay inside buildings. Under typical internal conditions, coronavirus particles are capable of remaining in the air for as long as 3 hours and travelling long distances.
Those particles may be carried by air streams inside rooms or exhaust air ducts coming out from a ventilation system. A special attention should be paid to the operation of hospital ventilation. And all of this is to ensure human health.
A properly set air handling unit contributes to the creation of intensive airflow and reducing the risk of infection inside buildings. What should we do with a ventilation system to support air purification?
1. Extend ventilation operating time
In buildings with mechanical ventilation systems it is worth extending their operating time. The system should be turned on a few hours before planned arrival of people inside rooms and then turned off a few hours after they have left the building. However, it is better (recommended) to keep the ventilation system on 24 hours a day.
2. Increase the volume of supply and extract air
It is recommended to supply as much external air to rooms as possible. The volume of supplied fresh air per person is a key aspect here. If the number of employees is smaller than usual, it is better not to place workstations in a small office space. Spreading workstations over a larger area and keeping greater distances between them is more beneficial. In order to enhance the air purification effect of a ventilation system, it is possible not to link ventilation with e.g. CO2 concentration and temporarily set the system at a constant, optimum level, keeping in mind that with high airflow the ventilation system may spread the virus over an entire room.
3. Check temperature and humidity
Keep the level of temperature and humidity in a ventilation system without a change. SARS-CoV-2 is immune to environmental changes, but it is also vulnerable to very high relative humidity (over 80%) and temperature over 30°C. Such conditions are neither achievable nor acceptable in buildings. The only help in this situation is using electrostatic nanofilters that catch virus particles in the air.
4. Rely on safe heat recovery and recirculation
In certain circumstances virus particles in extracted air can once again get inside the building. There are instances where the heat recovery devices transport virus particles connected to molecules suspended in the air through leaks. Therefore it is recommended to (temporarily) turn off rotary heat exchangers for the duration of the pandemic. The recirculation mode should be turned off as well.
5. Ducts cleaning has no practical effect
If you clean a ventilation system periodically in accordance with the Technical Conditions and Building Code you do not have to clean ventilation ducts more often, because the ventilation system is not the source of pollution. In this case, virus particles connected to small molecules do not settle on the ventilation ducts easily and they are not being transported to rooms by the airflow.
6. Replacement of external filters is not required
More frequent replacement of external air filters is not necessary. You can apply regular maintenance procedures.
7. Check the ventilation system in bathrooms and toilets
Air extraction systems in lavatories should be maintained 24/7, regardless of circumstances. Make sure underpressure is generated, especially in order to avoid spreading undesired particles.
Expert says!
Hospital ventilation is necessary
During flu seasons air purification is absolutely necessary. When an ill person sneezes or coughs, viruses and bacteria dissipate in the air very easily. Micro-organisms inhaled by other building users cause the spread of diseases. A properly set and active ventilation system makes it possible to purify the air we breathe of undesirable elements. If a ventilation system is not active or functions incorrectly, virus particles may remain in the air even for several hours.
Laboratory ventilation and hospital ventilation vs. different ventilation systems. What ventilation system should be used in offices?
In this case the option of adapting rooms to the existing situation, for example by creating appropriate room pressure systems, is very desirable. This can be achieved easily, if it is possible to configure VAV regulators (both supply and extract ones). The iFlow or SmayLab systems offer such an option. The former was created specifically for offices and public buildings. The latter, i.e. SmayLab, was designed for laboratories and hospitals. By using the iFlow system and controlling the difference in flow between supply and extract air in a room, we can create low overpressure or underpressure. This allows us to create a substitute for a protective barrier, which partially separates neighbouring rooms, e.g. office space from corridors.
This way you can easily create low overpressure in an office space by means of the iFlow system web server, which will make it more difficult for the air to penetrate to office rooms from a corridor. However, if you do not want the room air to move into a corridor (e.g. preventive disinfection of a room), you can set underpressure in the room. It will make it more difficult for odours or substances sprayed in the room to penetrate to the corridor. Knowing how much our customers value the possibility of freely changing parameters and based on our long-time experience in design, consulting and ventilation commissioning in laboratory rooms, we are on the verge of introducing a new generation of the SmayLab system. Laboratory ventilation with new generation systems provides high flexibility.
Such a system makes it possible to adjust the pressure in rooms by means of both real measurements (with the use of room pressure sensors) and theoretical calculations (by setting constant pressure difference between the air supply and the sum of exhaust systems in a room). The SmayLab system has successfully been used in many hospitals and laboratories for pressure gradation control in clean rooms. With the new edition we offer more flexibility and new capabilities to our customers. Nowadays, it is also worth paying attention to a possibility of using air nanocleaners, as they can capture, stop and eliminate up to 99.8% of nanoparticles, such as viruses, bacteria and fungi. These filters can stop particles as small as 0.001 μm.
Nanofilters vs. hospital ventilation
No HEPA fibre filter can capture them. Even if it were possible, moisture accumulating in the fibres might actually favour the replication of micro-organisms and it would be necessary to replace the filters quite often. Nanofilters stop particles as small as 0.001 μm. Please notice that particles smaller than 2.5 μm (i.e. 0.0025 mm) are the most harmful for human health, since they deeply penetrate pulmonary alveoli. 1 μm (0.001 mm) and bigger particles are mostly captured by mucous membranes of the upper respiratory tract (additionally, they can even penetrate to the circulatory system). The SmayLab and iFlow systems may be effectively used in healthcare facilities to purify the air supplied to rooms. This way you can minimise the probability of spreading viruses to other rooms handled by a given air handling unit via a ventilation system.
Basic features of the iFlow system:
• Measures and adjusts such parameters as temperature and CO2 emissions;
• Measures air quality parameters: VOC and humidity;
• Detects motion;
• Allows you to configure a room occupancy schedule individually for every room;
• Monitors room parameters and correct operation of VAV regulators;
• Controls the central unit and optimises ventilation system energy consumption;
• Equipped with a built-in web server that controls the system.
Benefits of the iFlow system:
• Reduces ventilation system operating costs;
• Controls VAV regulators and room parameters;
• Changes system parameters independently from a web server;
• Gets a dedicated solution with proven control algorithms.