Thermal modelling analysis carried out on the new extension showed that the initial design of the Break Out Room would not satisfy the BB 101 (Building Bulletin 101) natural ventilation or overheating requirements. It would also not receive an average daylight factor of at least 2% or greater.

Primary School Extension, Harlow - Thermal Modelling Analysis - 1In order to ensure that the new extension would meet the criteria set by BB 101 and also receive adequate day lighting, a couple of minor design changes were introduced.

The modified design for the new extension included a larger window to the Break Out Room. The existing 450mm high by 600mm wide window was increased to 550mm high and 1000mm wide. It can also open at least 250mm, the other opening windows and rooflights within the Class Base Hub can still be restricted to 100mm openings if required.

Primary School Extension, Harlow - Thermal Modelling Analysis - 2Increasing the size of the Break Out Room window allowed for sufficient natural daylight to now enter the space, achieving an average daylight factor of greater than 2%.

Primary School Extension, Harlow - Thermal Modelling Analysis - 4Increasing the larger windows opening width up to 250mm from 100mm ensured that an adequate amount of fresh air for its occupants would now enter the space, even on a day with no wind. The larger opening would also ensure that during the peak summer months the Break Out Room would not suffer from overheating as defined by BB 101.

Primary School Extension, Harlow - Thermal Modelling Analysis - 3The proposed modified design shows just one way in which the extension could be made to pass the relevant regulations. Other ways may be possible such as opening the rooflight within the Break Out Room.