Ventilate properly: CO2 sensors from Theben

Theben CO₂ sensors monitor CO₂ levels in schools and classrooms, in offices and meeting rooms or in passive and low-energy buildings. CO₂ sensors thereby make a decisive contribution to indoor air quality.
This site contains comprehensive information on CO₂ levels in indoor air and their effects as well as needs-driven and energy-efficient ventilation control using CO₂ sensors.

Contents:

• Classification of breathing air quality according to the Federal Environment Agency
• Background: Increased CO₂ levels and their consequences
• Application: CO₂ sensors in schools, offices, passive and low-energy houses
• Ventilation control: CO₂ sensors for appropriate ventilation control
• Measurement method: Non-dispersive infra-red
• Downloads and further information

Classification of breathing air quality according to the Federal Environment Agency

Background: Increased CO₂ levels and their consequences

We all know about badly ventilated houses, stuffy classrooms and meeting rooms. In addition to humidity and temperature, this is mainly due to exhaled carbon dioxide. An odourless and tasteless gas that is only detected by human beings due to its negative characteristics: feeling unwell, lack of concentration and deterioration in performance. Human beings absorb oxygen from the air when they inhale and release carbon dioxide into the air when they exhale. Inhaled air contains 21% oxygen and 0.035% carbon dioxide. In contrast, exhaled air contains just 16% oxygen and 4% carbon dioxide. While carbon dioxide is only harmful to human beings at concentrations of 2.5% and above, performance levels, concentration and well-being are adversely affected at a concentration of 0.1 % (1,000 ppm).

After just a few minutes, carbon dioxide levels reach 5,000 to 6,000 ppm in enclosed spaces like classrooms, offices or meeting rooms where people often congregate and which are subject to restricted ventilation. Theben CO₂ sensors measure CO₂ levels reliably. The measured values serve as an indicator for the ventilation control to increase the intake of fresh air.

Excursus: Max von Pettenkofer makes room air quality measurable

Max von Pettenkofer (3. December 1818 to 10. February 1901) was a professor of medical chemistry at the Ludwwig Maximilian University Munich and the first German professor of hygiene from 1865. With his studies on carbon dioxide levels 140 years ago, he laid the foundation for our current regulations relating to air quality (DIN-1946-2). This standard sets an upper CO₂ limit of 1,500 ppm. That means there should only be 1,500 CO₂ molecules per million air particles.

CO₂ level

Caption: Typical CO₂ levels (in ppm) and their affect on human beings.

1000 ppm CO₂ – the threshold for good indoor air quality

Really good indoor air quality does not exceed a threshold of 1,000 ppm CO₂. Therefore, DIN 1946-6 requires an outdoor air flow of 30m³/h per person. A carbon dioxide level of 1,000 ppm CO₂ is not achievable by occasional ventilation or opening windows given modern building standards and the thickness of the outer shells of buildings. It is often the case that windows in public buildings such as schools, classrooms or large offices cannot be opened: Good indoor air quality can only be guaranteed in such cases by using a ventilation system controlled by a CO₂ sensor.

Application: CO₂ sensors in schools, offices, passive and low-energy houses

Due to legal requirements, modern buildings now have very good thermal insulation. In order to keep heating costs as low as possible, windows, outer walls and roofs - the entire building envelope - are so well insulated that an exchange of air is impossible. The result is, in addition to an increased CO2 concentration, also increased moisture, which quickly leads to the formation of mold in the building. Health risks from fungal spores, etc. are thus preprogrammed. In order to sustainably avoid health risks and structural damage, a needs-based supply of fresh air is essential, especially in modern buildings such as passive and low-energy houses.
This is where CO2 sensors from Theben come into play: In addition to the CO2 concentration, CO2 sensors also measure the relative humidity in the building. If defined values ​​are exceeded, CO2 sensors such as the AMUN 716 S KNX send a signal to the building automation, e.g. E.g .: KNX, and the ventilation system increasingly controls fresh air or opens a window automatically. Conventional control is also possible with Theben CO2 sensors such as the AMUN 716 SR: It controls the ventilation system directly.

Ventilation control: CO₂ sensors for needs-driven ventilation control

Together with modern building systems technology such as KNX, CO₂ sensors make an enormous contribution to saving energy. Ventilation is a matter of guesswork without CO₂ sensors. And that's mostly too late or too much. Too much in this context means heat and heating costs are lost with the exchange of air. This is where Theben CO₂ sensors come to the fore: The readings of the CO₂ sensor show when, and for how long, ventilation is required. The ventilation system only introduces fresh air as long as it is actually required. In addition to the heating energy saved, speed-controlled ventilation via CO₂ sensors also offers large potential savings with fans in ventilation systems. The output of a fan depends on the third power of its speed. A reduction in speed of 20% leads to the halving of electricity consumption.

Volume flow

Caption: CO₂ sensors enable great potential savings in energy costs (green surface).

Measurement method: Non-dispersive infrared process

Theben CO₂ sensors measure CO₂ levels via infrared spectroscopy, also known as non-dispersive infrared process (NDIR). As CO₂ reduces the incidence of infrared light on the CO₂ sensor, the received signal changes in relation to the CO₂ levels in the indoor air.

Service Hotline
Our hotline is available to help you with any questions about CO₂ sensors:
+49 7474/ 692-369

Our hours of operation:
Monday to Thursday: 7 a.m. to 6 p.m. and Friday: 7 a.m. to 4 p.m.
During off-service hours you can contact our hotline: hotline@theben.de