BB101 contains the guidelines issued by the Education & Skills Funding Agency, to address the Ventilation, Thermal Comfort and Indoor Air Quality in Schools. BB101 was finally re-issued in August 2018. 

It provides guidance on draught, carbon dioxide levels and temperature criteria based on an adaptive approach. It prescribes filtration standards and refers to BB93 where noise is concerned. 

A significant difference to the earlier version (issued in 2006) is the acceptance of hybrid systems, whereby elements of mechanical and natural ventilation may be used for the same space.