Siemens Building Technology provides the building control solutions for the Seattle School District. The school district has been installing CO2 monitors in gyms, auditoriums and some school classrooms as a way to ensure good air quality and a healthy teaching environment. They are also now realizing that there is an energy benefit to CO2 control in that they can control fresh air ventilation based on actual occupancy. Air quality is assured, but if occupancy is low, less outside air has to be heated or cooled.
After using CO2 control for the past 4 years, there was some frustration at the level of maintenance necessary to keep the sensors calibrated. They had tried most of the major brands of sensors but found that they were often drifting out of calibration.
Siemens evaluated the AirTest TR9220 self-calibrating CO2 sensor in October of 2001 in a pilot installation and found that it did not have the drift problems they experienced with other sensors. They were also impressed with the historical data available from AirTest on the sensor performance and the fact that it was manufactured using ISO 9001 quality procedures. The AirTest product is one of a very few sensors that is manufactured under such stringent quality standards. Siemens and the Seattle School District have now standardized on the AirTest TR9220 CO2 monitor.
AirTest CO2 monitors & the seattle school district case study