AIR TIGHTNESS TEST - New Dwellings
AIR PRESSURE TESTING (Regulation 20B) Currently any new dwellings being designed when constructed will be required to have an AIR PRESSURE TEST carried out on them by an authorised contractor, in accordance with the Air Tightness Testing and Measurement Association (ATTMA) standards, The contractor should be a suitably qualified person preferable ATTMA registered. This requirement for Air Permeability Compliance is the leakage of air in, or out of the constructed building per square metre of the buildings’ envelope (m3/hour), this is at a pressure difference of 50 Pascals (m3/h(.m2)@50pa) between the inside and the outside of the building. The worst acceptable air permeability reading is 10 m3/hr per m3 @ 50Pa.
Construction Tip
CONSTRUCTION TIP - AIR LEAKAGE PATHS. There are many possible air leakage paths. One such path in the case of the now popular ‘dot and dab’ method of securing sheets of plasterboard to the internal blockwork skin of the dwelling is air escaping into roof voids, or out through wall vent locations. A very simple and effective way to prevent this particular escape route, is to use a building sealant/foam to seal the top of the plasterboard sheet to the blockwork inner skin of the dwelling (see Diagram 1). This prevent air leaking into the roof void, a similar situation can happen where holes have been provide in the external cavity wall to accommodate trunking for extraction fans or waste pipes, using an effective sealant at this junction is vitally important to prevent air escaping. Obviously around window and door frames is another possible escape route but at the end of the day, only good construction practices will prevent the new dwelling failing the AIR PRESSURE TESTING process.
 |
 |
 |
 |
|---|