Over the last few years, there has been a huge pressure to reduce the energy use intensity of new and renovated buildings, where an increasingly better building envelope in terms of thermoinsulating properties is being imposed by normative requirements. However, each coin has two sides and this case is no different. Insulated buildings with well-sealing windows have stopped breathing naturally, which can have a very negative effect on human health. The situation is even worse in areas with an increased concentration of people, such as schools.
You know it yourselves. In airless rooms we feel tired, have a headache and we concentrate worse. It’s not a lack of oxygen but an increased CO2 concentration. Outdoors, CO2 comprises about 0.04 % of the air (400 ppm), but in the exhaled air it is as much as 4 % (40 000 ppm). Staying in an area with an increased CO2 concentration disturbs the acid-base balance of our blood. It subsequently becomes more acidic (its pH decreases) and its oxygen transport capacity is on the wane as haemoglobin’s ability to bind oxygen is reduced.
Effect of CO2 concentration on human organism:
- 350-400 ppm - level in outdoor environment
- do 1000 ppm - recommended indoor CO2 level
- 1200-1500 ppm - recommended maximum indoor CO2 level
- 1000-2000 ppm - signs of fatigue and reduced concentration set in
- 2000-5000 ppm - potential headache sets in
- 5000 ppm - maximum safe concentration without health risks
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5000 ppm - nausea and accelerated pulse
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15000 ppm - breathing problems
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40000 ppm - potential loss of consciousness
If you want to eliminate the amount of CO2 in the room, you have to ensure ventilation amounting to 25 m3/hr per person. This can of course be ensured by windows, but this would mean changing the ventilation habits considerably in renovated buildings. A much more efficient, reliable, but also more expensive solution is to let some equipment take care of this. A high-quality and quiet air-conditioning system with recuperation, controlled by a CO2 sensor, is an ideal option.
Are you planning to install an air-conditioning system and want to have a project prepared? For a consultation or price quotes, do not hesitate to take advantage of free consultations with the Enerfis team at +420 222 766 950 or info@enerfis.cz.