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
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