Air Tightness Testing
The air-tightness of a building is known as its 'air permeability' or leakage rate. Air leakage can occur through building defects such as gaps, holes or cracks in the fabric of the building envelope. Air gaps often exist because of poorly constructed seals around partitions, particularly at the joins with floors, ceilings, windows, doors, service pipes and ducts. This uncontrolled air leakage affects the building's performance in the following ways:
- Energy losses and reduced occupant comfort levels
- Compromised health for the occupant
- Reduced Acoustic comfort
- Pollen and Dust
- Mildew and Mould
- Insulation Fibers
Energy Losses and Reduced Occupants Comfort Levels
Uncontrolled air infiltration represents a sizeable portion of the energy losses in a building, estimates range from between 20 and 30%. Early detection of these building defects can reduce energy costs and increase the thermal comfort of the building.
Compromised Health for the Occupant
Defects in the building envelope can results in pollutants and irritants entering a dwelling space. These pollutants are typically drawn from the attic, under the floor, garage or directly from outside. Air pressure testing can assist in reducing the volume of harmful particles such as:
Reduced Acoustic Comfort
Acoustic comfort is a key element in a superior indoor environment. If there are defects in the building envelope leading to air permeability from the outside or between apartments this can adversely affect the acoustic comfort inside.
Air Permeability Regulations
Air permeability testing is now part of the Building regulations Part L 2007 and it applies to dwellings, where the work commences or takes place, on or after 1 July 2008. The process involves temporarily sealing all the required air vents in the dwelling, and then carrying out a pressurisation test on the building envelope. To comply with building regulations the achieved Air Permeability rate should be less then 10m3/hr/m2 @50Pa. In reality designers and builders should aim for a better result. BST can provide training and seminars to developers and architects to help meet these requirements from day one.
Building Science Technologies carry out all air permeability tests in accordance with the procedures detailed in ATTMA TS1 and BS EN 13829: 2000.
