From planning to completion, great cooperation is the key to quality construction. Air Leakage Testing depends on all trades and the site manager understanding what will be required.
The impact of a ‘failed’ Air Leakage Test can be serious, impacting completion and handover deadlines. When the initial SAP/SBEM calculations are made, a target Air Leakage Test result is assumed in order to produce the Target Emission Rate (TER). The TER has been part of the UK’s regulations for over a decade now and helps to ensure that new buildings are designed to use less fuel, meaning a lower carbon footprint and lower energy costs. If you miss the target air test result, you can fail the TER.
Most design teams are familiar with the construction details needed in their plans to ensure the building is efficient enough to comply. However, this is based on calculations and can’t account for the quality of construction, which is why the Air Leakage Test is required at Final Fix Stage (and potentially Shell and Core for commercial buildings).
All on-site trades need to be aware of the implications of the Air Test in order to seal areas that will later become inaccessible once building work is complete, for example loft spaces, joists, suspended ceilings and especially behind kitchen and bathroom cabinets.
When the main construction work is complete, the appointed Air Leakage Test Engineer will need to know the target result before testing begins. If this is not known, an assumption may be made that the building just needs to reach the Part L compliance figure of 10m3/hm2. In this case any potential issues that could be rectified before the test commences may not be flagged to the Site Manager and may result in a non-compliant result.
If the on-site Air Leakage Test result does exceed the predicted target and lead to non-compliance, there are several options to remedy this. The buildings test result will need to be improved by sealing common areas for leakage, so it’s useful to have a site operative on hand to do this as the engineer completes the testing.
Sharing information is a step that can be easily overlooked, especially when you consider the various teams involved on site. The Air Leakage Test result can be the difference between getting final sign off and being forced to carry out unplanned improvements to a brand new building.