The corona pandemic triggered by the SARS-CoV-2 virus has led to increased discussions about indoor air hygiene. One component is the way in which ventilation systems or air handling units (HVAC) are equipped. These systems make an important contribution to the protection of people, employees and safe production processes. Upgrade your ePM 2.5 filter system now to keep your ventilation technology up to date.
The Federation of European Heating, Ventilation and Air Conditioning associations (REHVA) is a HVAC association that develops and promotes energy efficient, safe and healthy technology for mechanical services of building. In a continuously updated COVID-19 manual REHVA* focuses on the reopening and safe use of buildings. In addition, there is advice on specific components such as building and room types and concrete measures.
One way in which viruses are transmitted from person to person is via droplet infection. When people talk, cough or sneeze, viruses are distributed in the air by droplets <5 μm in size. Because of the limited volume of air, infectious particles accumulate more easily indoors than outdoors. If several people remain together in an indoor space, the risk of infection increases.
To minimize the risk of infection indoors, air filtration systems play an important role. High-performance filter elements are able to separate these particle sizes almost completely and thus reduce the concentration of germs indoors. Individually adapted filter concepts minimize the risks of contamination – the combination of different filter classes ensures the desired indoor air quality.
The most important contents briefly summarized:
- SARS-CoV-2 airborne transmission and general recognition of long-range aerosol-based transmission have made ventilation measures the most important engineering issue in the infection control.
- Regarding airflow rates, more ventilation is always better, but it is not the only consideration.
- There is currently no evidence of human infection with SARS-CoV-2 caused by infectious aerosols distributed through the ventilation system air ducts. The risk is rated as low.
- Well-maintained HVAC systems securely filter large droplets containing SARS-CoV-2/ COVID-19 aerosols.
- Small droplets and droplet nuclei can spread through HVAC systems within a building (or vehicle) and stand-alone air-conditioning units if the air is recirculated.
- HVAC systems have a complementary role in decreasing transmission in indoor spaces by increasing the rate of air change, decreasing the recirculation of air, and increasing the use of outdoor air.
- There is no benefit or need for additional maintenance cycles in connection with COVID-19.
- Consideration should be given to extending the operating times of HVAC systems before and after the regular period.
- Avoid air recirculation as much as possible. The general advice is to supply as much outside air as reasonably possible.
- Increasing the number of air exchanges per hour will reduce the risk of transmission in closed spaces.
- In buildings without mechanical ventilation systems, it is recommended to actively use openable windows. Window opening is the only way to boost air exchange rates.
- Change of outdoor air filters is not necessary.
- Clogged filters are not a source of contamination.
- Filters must be replaced according to the normal procedures when pressure or time limits are exceeded.
- Air cleaners need to have HEPA filter efficiency.
- Air cleaners are a way to apply short-term mitigation measures. In the longer run, ventilation system improvements to achieve adequate outdoor air ventilation rates are needed.
How you can easily and effectively convert your system and what preventive measures are available, our experts will talk about this in two free webinars "Ventilation suitable for infection control". Register now and watch for free!
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VDMA: Raumlufttechnische Anlagen in Zeiten von COVID-19: Bewertung des Infektionsrisikos durch aerosolgebundene Viren bei unterschiedlichen Lüftungs- und Luftreinigungsverfahren in Räumen, February 2021