Summer Overheating Calculations

Included within Part L of the Building Regulations there is a requirement to ensure all newly constructed commercial property remains comfortable to occupants during the hottest of UK summers.

Criterion 3 of Approved Document L2A states:-

63 For occupied spaces excluding spaces such as stacks, unoccupied atria intended to drive natural ventilation via buoyancy and spaces adjacent to display glazing that are not served by air conditioning systems, provisions should be made to limit solar gains so as to reduce internal temperature rise in summer. This can be done by an appropriate combination of window sizing and orientation, solar protection through shading and other solar control measures, and by using thermal capacity coupled with night ventilation.

64 Goes on to state, Reasonable provision would be to show for every occupied space which is not air conditioned that:

a) When a building is subject to solar irradiances for July combined solar and internal casual gains per unit floor area averaged over the period 0630 to 1630 GMT is not greater than 35W/m².or

b) The dry resultant temperatures over 28 degrees C should not exceed 1% of the annual occupied period. (figures applicable to offices, other uses may be subject to variance)

L2 Energy Consulting have the experience to calculate Summer Overheating to meet Building Control Requirements. For further information please call on 0845 272 3500.