Building Bulletin 101

The Building Bulletin 101 "Ventilation of School Buildings" provided by the Department for Education and Skills (DfES) states the performance standards for ventilation in schools. The standards require that ventilation be provided to limit the conentration of carbon dioxide in all teaching and learning spaces. The bulletin states that the average concentral of carbon dioxide should not exceed 1500 parts per million (ppm) when measured at seated height, during the continuous period between the start and finish of teaching on any day.

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:.

Specific Ventilation Requirements

1. a minimum of 3 l/s per person (litres per second per person), and
2. a minimum daily average of 5 l/s per person, and
3. the capability of achieving a minimum of 8 l/s per person at any occupied time. To achieve this extra ventilation, additional ventilators could be used e.g. supplementing windows with the addition of louvres or stacks. Although this ventilation rate may not be required at all times of occupancy, but it should be achievable under the control of the occupant. When fresh air is supplied at a rate of 8 l/s per person, the carbon dioxide concentration will generally remain below 1000 ppm.

Further Requirements

It is required that these flow rates should be based on the maximum number of occupants likely to occupy the space, and should be achieved under the design conditions. The design conditions are based on the temperature profile from one of three defaults: winter temperature profile; summer temperature profile; mid-season temperature profile. It is also possible to specify alternative design condition by specifying appropriate temperature profile.

Please note that for other spaces with special learning activities such as science laboratories and food technology rooms, the ventilation rates above may not be suitable.

How can we help you?

We can assist you during the design stage to model and understand various ventilation strategies to ensure that the learning spaces are compliant with the standards. The results of our calculations can be used to demonstrate compliance with the performance standards.

To discuss your requirements, please contact us on:


11 Caithness Crescent
Manor Kingsway
Derby DE22 3XS


01332 492082


0788 6277 818