Top 10 steps to reduce Airtightness test failures:
Air tightness testing is often viewed as a nuisance – but you need it for Building Control compliance and therefore for Practical Completion.
So why not get it tight first time and avoid potential delays and costs caused by failing air tightness tests.
Build Check work pro-actively with clients to help ensure the risk of failure is minimised – there are 10 steps you can take prior to testing to avoid additional cost and delays:
1. Identify your Target Leakage rate specified in your SBEM or SAP calculation for the building. A target of 5m3/hr.m-2 or less means that a building must be both designed and constructed with Airtightness in mind
2. For low leakage rate buildings, Build Check provide on site Design Reviews undertaken with members of the Design and Construction teams. This is not expensive and helps ensure all parties give due consideration to air tightness.
3. Site inspections should be undertaken at key stages of the construction – including prior to installation of ceilings and say 1 month prior to the test.
4. Large buildings often fail their first test via leakage through ductwork systems. Discuss effective sealing of these with M&E Contractor
Typical leakage paths include:
5. Dry lining – air must not get behind dry lining. The interface between floor slab and soffit should be sealed around complete test evnvelope.
6. Metal decking – profile fillers should be used around the perimeter of the test envelope. Seal joints/sheets. Perforated decking – avoid if at all possible!
7. Column casings – must not let air into wall cavity or behind dry lining.
8. For low leakage rate buildings, do not purely rely on wall membranes to act as your airtight barrier. A “belt and braces” approach should be adopted and the dry lining should therefore also be used as the primary ATB.
9. Services penetrations and risers: check service penetrations are sealed eg behind bath panels, within ceiling voids and that door/access panels are air tight.
10. At interface between structural steelwork and the ATB / Dry lining – especially check hard to reach places.
About Build Check
We are a team of highly skilled UKAS and ATTMA accredited specialists, providing both on-site and laboratory based testing and certification services to the construction and fenestration industries. Our knowledge of the latest building regulations is unmatched. Having quickly and accurately evaluated your requirements we will provide you with honest, impartial advice on how you can achieve compliance.