Air Tightness Testing

Air tightness testing or air permeability testing is a  mandatory building control requirement and current regulations state a maximum air leakage of 10 m³/ (hr*m²) @ 50 Pa must be achieved.

Air leakage contributes considerably to heat loss from a building and is one of the easiest elements of building energy efficiency to understand as everyone has experienced a cold draught before. As building technologies have developed, particularly PVC windows and doors, these draughts are less likely to be as obvious however as they occur at multiple points the cumulative effect is considerable. Often the majority of air leakage can occur between floors and manifests itself as a strong draft which can be felt at down lighters. . There are many other areas which need  attention such as window cills, electrical conduits, waste pipes, extract fans and the junction between the wall and the floor. Timber Frame houses need particular care as there is the potential for air leakage everywhere unlike traditional construction which benefits from a solid internal skin.

As with all areas relating to building energy the earlier we are involved in a project the better as we can advise on how the desired levels of air tightness can be achieved. If we are responsible for your Design SAP we will already know what level of air tightness is required to achieve compliance and can act accordingly.

It is important to remember that all buildings (and their occupants!) need to breathe. Whilst air tight buildings are energy efficient they require ventilation. We would always recommend MVHR (Mechanical Ventilation Heat Recovery) in new build, air tight dwellings. Under current building regulations in England & Wales it is virtually impossible to show compliance without very good air tightness and MVHR. These regulations are expected to be introduced in Northern and Southern Ireland in 2017.

Build Tight, Ventilate right

Draught Proofing

As air leakage, particularly in older commercial buildings, is responsible for as much as 25% of heat loss its often financially viable to test these buildings, highlight the areas of loss and make repairs. This is an inexpensive way to reduce fuel consumption and also improve the property’s EPC rating.

Ductwork Leakage

Air handing ductwork deteriorates over time and often escapes routine maintenance. Leakage occurs at joints and from penetrations to the Duct wall such as taps, valves etc. It stands to reason that the more air lost through leakage, the more air has to be ‘pushed’ through the ductwork in turn requiring more energy. In cases were conditioned air (either heated or cooled) is being moved then the losses are even greater as the energy required to condition the air is also lost when there is leakage to an unconditioned space. As with draft proofing is often financially viable to test the ductwork and repair the leaks. Again this is an inexpensive way to reduce fuel consumption and also improve the property’s EPC rating

Appliance Spillage Testing

Appliance spillage tests are required by building control under part J (Part L in N Ireland) when there is an ‘open flued’ appliance in a room with and extract fan. As many new dwellings have a stove in an open plan Kitchen Living area (or in any room if the dwellings has MVHR) this test will be required. The test is required to show that there is sufficient draw from the appliance to counteract the air movement induced by the fan. Otherwise the appliance fumes may be drawn out of the appliance into the room by the extractor fan.