Air supply notes and exceptions

Notes: (1) Extract fans should not be installed in the same room or space as a solid fuel burning appliance, see paragraph 2.17. (2) For simple open fires as depicted in Diagram 3.12 the air supply requirement can be met with room ventilation areas as follows - Nominal fireplace opening size 500 mm 450 mm 400 mm 350 mm | Total equivalent area of permanently open air vents 20500 mm2 18500 mm2 16500 mm2 14500 mm2 (3) A dwelling constructed prior to 2008 should not normally have an air permeability of less than 5.0 m3/(h.m2) at 50 Pa unless extensive measures have been taken to improve air tightness, see Appendix C. When it is not possible to determine if the air permeability of a dwelling is likely to be more than 5.0 m3/(h.m2) then it should be assumed that the dwelling has an air permeability of 5.0 m3/(h.m2) or less.