General Ventilation Requirements
The standard also recommends that the maximum concentration of carbon dioxide should not exceed 5000 ppm during the teaching day and also that the occupants should be able to lower the concentration of carbon dioxide to 1000 ppm at any occupied time, including during teaching.
To meet these CO2 performance standards for normal classrooms, BB101 also states the minimum ventilation rates to be provided by any ventilation system (i.e. controllable devices to supply air to and extract air from a building) as follows:.