Commercial Buildings – L2
Commercial Air Permeability Testing has been required to new buildings since 2003 and is currently covered by Building Regulations 2010 Part L2. Similar to Domestic Buildings, the maximum permitted Air Permeability under Building Regulations is 10m³/hr.m², however building energy calculation targets (detailed within the SBEM Calculation) of 5m³/hr.m² or even an onerous 3m³/hr.m² are often being specified.
BAT testing engineers are very experienced at testing a wide variety of commercial properties (e.g. student accommodation blocks, care homes, office blocks, schools, hospitals, supermarkets, industrial units, laboratories, etc) and have an excellent record of working with contractors to identify and rectify air leakage paths, often being able to retest on the same visit at no extra cost.
When undertaking an Air Permeability Test it is important to achieve the required 50 Pascals pressure required for an ATTMA compliant test. BAT have a large number of door fan units available that can be brought to site and for large buildings have a vehicle mounted fan unit with it’s own generator capable of providing up to 27m³/s. For extremely large buildings BAT can utilise the vehicle mounted fan unit in conjunction with additional doorfan units to achieve the required pressurisation.
Building Air Permeability Tests are able to be undertaken with either positive or negative pressurisation and BAT would advise as to the most appropriate method for the building being tested. Often the most appropriate method would be determined by the nature and location of the building ventilation temporary sealing works required.
Smoke Testing can be a useful means to identify air leakage paths on complex leaky buildings since air leakage paths are not always obvious. BAT offers smoke testing as a testing option. A positive pressure, achieved with doorfans, needs to be used once the building or area has been filled with smoke to reveal where the smoke is exiting the building envelope.