"The SBEM default value of 25 m3/hr m-2 for all existing buildings shall be amended as follows: Less than 10 m3/hr m-2 – only with an accredited air pressure test result 10 m3/hr m-2 – buildings > 500 m2 built to 2002 Building Regulations 15 m3/hr m-2 – buildings <= 500 m2 built to 2002 Building Regulations and buildings built to 1995 Building Regulations 25 m3/hr m-2 – buildings built to Building Regulations pre 1995 35 m3/hr m-2 – to be considered where buildings are pre 1995 regulations and where suitable evidence of high permeability exists, e.g. single skin metal clad structure within Planning Use Class B2 – B8 with large roller shutter doors and poor constructional details etc."