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supplementary IAQ sensor (Indoor Air Quality) for assessing room air.

VOCOOsx frontview

The BAPPU-VOCOOsx is a supplementary IAQ sensor (Indoor Air Quality) for assessing room air. VOCOOsx measures the concentration of carbon dioxide (CO2) in room air and - by means of "Total Volatile Organic Compounds" (TVOC) measurement - provides an additional indicator for assessing room air. A further option available is the measurement of carbon monoxide (CO) which complements the IAQ sensor.

The NDIR measurement method (non-dispersive infrared spectrometry) ensures accurate results when measuring CO2 levels. The additional TVOC sensor determines the sum value (isobutylene equivalent level) of the TVOC that could be present in room air.

In contrast to other devices that are only capable of displaying single CO2 equivalents by means of TVOC measurements, BAPPU-VOCOOsx has individual autonomous sensors at its disposal. In some cases, there is a correlation between CO2 and TVOC; moreover, ambient air pollution can be reduced in both cases utilising similar measures such as the supply of fresh air; however, the various causes of the pollution can only be determined by means of separate detection methods.

Measurement sizes

VOCOOsx backview
  • Particulate Matter PM1, PM2.5, PM10

  • CO2 – carbon dioxide (0 – 10.000 ppm)

  • TVOC – total volatile organic compounds (100 – 2000 ppb)

  • CO – carbon monoxide (0 – 500 ppm)


VOCOOsx frontview 2
  • Accurate NDIR CO2 measurement method

  • Additional TVOC indicator

  • Continuous recording in conjunction with BAPPU-evo

  • Optional possibility to measure CO


What are the distinguishing factors for ideal room air?
In today’s world, it is prevalent for people to spend the greater part of the day in enclosed spaces. Therefore, indoor ambient air conditions are becoming all the more important, especially in view of the fact that such conditions often influence well-being and performance. But when do we know if  the ambient room air is at an optimal level? Apart from CO2, we have to consider other criteria, such as unpleasant odours or substances that are hazardous to health, which play a role.

Carbon dioxide (CO2)
CO2 is considered to be a significant indicator for the current circumstances regarding ventilation in enclosed spaces. However, CO2 only becomes unpleasant for people when it is in concentrations clearly above those that are in the outside air. According to the German Technical Rules for Workplaces 3.6 [Technische Regeln für Arbeitsstätten ASR 3.6], this can affect attention and lead to fatigue, which in turn indicate insufficient ventilation. Rising levels of CO2 also cause an increase of organic emissions and odours that every human being emits.

The measurement of CO2 is still an important aspect for objectively determining air quality. Therefore, in order to be able to obtain comprehensive data, especially with regard to the non-human influences on the room air, the existing BAPPU-CO2 sensor was enhanced.

Total Volatile Organic Compounds (TVOC)
TVOC, which are gaseous substances of organic origin, play a special role. A great many solvents, liquid fuels and synthetically produced substances can occur as TVOC, as well as organic compounds which are formed during biological processes. TVOCs are often detected in the air after construction and renovation work. They do not have to be a direct health hazard, but can lead to unpleasant odours, irritation and other symptoms. In other words, TVOC can contribute decisively to an uncomfortable room climate and, according to the German Technical Rules for Workplaces 3.6 [Technische Regeln für Arbeitsstätten ASR 3.6], should also be avoided as substance loads.

Carbon monoxide (CO)
CO occurs where carbonaceous materials are (not completely) burned or other chemical processes are initiated. In enclosed spaces, it is very often the outside air, for example from busy roads, that is responsible for the increase in concentration of CO. However, sources in the enclosed space itself can also cause the concentration of CO to be several times higher than the outside air concentration. Furnaces or fireplaces that do not draw up the fumes correctly, a leaking chimney, a gas stove, cigarette smoke, as well as the storage of wood pellets or the use of petrol-driven machines for levelling screed, can also contribute to an increased concentration of CO in enclosed spaces. Even a small amount of CO in the room - a level that is well below a hazardous concentration - will be sufficient to disturb physical comfort-being and reduce efficiency. It is for these reasons that ELK has integrated the measurement of CO into its BAPPU-Vocoo, which also reflects the extended area of application of BAPPU-evo in indicative measurement.

BAPPU is a product by

ELK - Gesellschaft für Erstellung, Layout und Konzeption elektronischer Systeme mbH


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