Class 4 buildings are typically a single dwelling in a Class 5, 6, 7, 8, or 9 building, such as the caretaker’s residence. 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 5 buildings do not contain accommodation, the acoustic requirements of Part F5 of the BCA do not apply, unless the Class 5 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 5 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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Definitions
Discontinuous construction:
Wall systems listed in Table 2 having a minimum 20 mm cavity between 2 separate leaves, with
(i) For masonry, where wall ties are required to connect leaves, the ties are of the resilient type,
(ii) For other than masonry, there is no mechanical linkage between leaves except at the periphery
Are deemed to be discontinuous construction.
Habitable room means a room used for normal domestic activities, and—
(a) includes a bedroom, living room, lounge room, music room, television room, kitchen, dining room, sewing room, study, playroom, family room and sunroom; but
(b) excludes a bathroom, laundry, water closet, pantry, walk-in wardrobe, corridor, hallway, lobby, photographic darkroom, clothes-drying room, and other spaces of a specialised nature occupied neither frequently nor for extended periods
Verification Method means a test, inspection, calculation or other method that determines whether a Building Solution complies with the relevant Performance Requirements.