User Manual
Table Of Contents
- 1 Purpose of this document
- 2 Why is a healthy, productive indoor climate so valuable?
- 3 The role of building automation in health and productivity
- 4 Control applications and targets (CO2, VOC, RH, PM2.5)
- 5 Recommendations for specific building types
- 6 Monitoring indoor climate parameters for health and productivity
- 7 Controlling indoor climate parameters for health and productivity
- 8 Products for a healthy productive indoor climate
- Appendix 1: Indoor air quality (IAQ) – Combined CO2 and VOC sensors
- Appendix 2: Integration of RDF../RDG.. (KNX) in Desigo
- Appendix 3: Other indoor climate parameters – NO2, SO2, O3
- Appendix 4: Tender texts
- External references
- Siemens reference documents
- Glossary
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Appendix 1: Indoor air quality (IAQ) –
Combined CO
2 and VOC sensors
CO2 concentration is measured in parts per million (ppm). Fresh outdoor air is around
400ppm and indoor levels of up to 1000ppm are acceptable. However, there is much more to
indoor air quality than just CO
2 concentration. Volatile Organic Compounds
1
(VOCs) are not
detected by CO
2 sensors, and yet are major contributors to the health problems associated
with sick building syndrome.
Siemens offers combined CO
2/VOC sensors
2
which control ventilation based on both CO2 and
VOC levels. This combined signal is referred to as IAQ (indoor air quality).
The IAQ sensors have two separate sensing elements, one for CO
2 and the other for VOC. The
sensor output reflects the higher of the two values. In the scenario shown in the graph, the
CO
2 level is in the green, acceptable range. However, the VOC is too high, so the (IAQ) sensor
will act according to the level of VOC, and the room controller will increase the supply of fresh
air even though the CO
2 level is good.
For a healthy, productive room, free from damaging levels of CO
2 and VOC, Siemens
recommends choosing one of its IAQ room sensors: for example, the flush-mount room
sensors AQR2548NF + AQR253xNNW or wall-mount room sensors QPA2002.
These IAQ room sensors are specified in the example applications in Chapter 7.
However, there are similar options to control CO
2 only or VOC only.
1 There is no general acceptable level of VOC as there is usually a mixture of volatile gases, some of which are
more dangerous than others. Siemens VOC sensors are sensitive to a broad range of oxidizing and reducing
gases, giving an indicative measure (0-100%). A starting point can be to control to below 50%.
2 See details of the AQR.., QPA.. and QPM.. sensors in the respective datasheets.
Note: IAQ duct sensors are QPM2102..