Class 7a buildings are typically buildings used for carparking for any number of vehicles more than 3. For a more complete definition refer to Clause A3.2 of the Building Code of Australia.
Sound transmission and Insulation
The objective of providing insulation to reduce sound transmission is to prevent loss of amenity due to undue sound being transmitted between accommodation units, or to a unit, from other parts of the building, such as plant rooms, lift shaft, common corridors, or from a different classification in the same building for example, car park, shops, commercial premises.
Building requirements
As Class 7a buildings do not contain accommodation, the acoustic requirements of Part F5 of the BCA do not apply unless the Class 7a portion adjoins one of the following building classifications within the same building:
- Class 2 – residential units
- Class 3 - boarding houses, motels and residential parts of hotels
- Class 9c – aged care buildings
Should a class 7a building share a wall, floor or ceiling with one of the above building classifications, the corresponding acoustic requirements for the adjoining classification should be used in designing that building element.
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