NT Part F7 Sound transmission and insulation

Floors separating sole-occupancy units must provide insulation against the transmission of airborne and impact generated sound sufficient to prevent illness or loss of amenity to the occupants.

Walls separating—

1. sole-occupancy units; or
2. a sole-occupancy unit from a plant room, lift shaft, stairway, public corridor, public lobby or the like,

must provide sufficient insulation against the transmission or airborne or impact generated sound sufficient to prevent illness or loss of amenity to the occupants.

The required sound insulation of floors and walls must not be compromised by the incorporation or penetration of a pipe or other service element.

(1) Walls separating—

1. sole-occupancy units; or
2. a sole-occupancy unit from a kitchen, bathroom, sanitary compartment (not being an associated ensuite), laundry, plant room or utilities room,

must provide insulation against the transmission of airborne sound sufficient to prevent illness or loss of amenity to the occupants.

(2) Wall separating a sole-occupancy unit from a kitchen or laundry, must provide insulation against the transmission of impact generated sound sufficient to prevent illness or loss of amenity to the occupants.

(1) Where a Deemed-to-Satisfy Solution is proposed, Performance Requirements F7P1 to F7P4 are satisfied by complying with NT F7D2 to NT F7D9.

(2) Where a Performance Solution is proposed, the relevant Performance Requirements must be determined in accordance with A2G2(3) and A2G4(3) as applicable.

The Deemed-to-Satisfy Provisions of this Part apply to Class 2 and 3 buildings and Class 9c aged care buildings.

A form of construction required to have a certain weighted sound reduction index (R_W) must—

1. have the required value determined under AS/NZS ISO 717.1; or
2. comply with NT Specification 28.

A floor separating sole-occupancy units must have an R_W not less than 45.

A wall must have an R_W not less than 45 if it separates—

1. sole-occupancy units; or
2. a sole-occupancy unit not within a Class 9c building from a plant room, lift shaft, stairway, public corridor, hallway or the like; or
3. a sole-occupancy unit in a Class 9c building from a kitchen, bathroom, sanitary compartment (not being an associated ensuite), laundry, plant room or utilities room.

(1) Except for a Class 9c building, a wall separating a bathroom, sanitary compartment, laundry or kitchen in one sole-occupancy unit from a habitable room (other than a kitchen) in an adjoining unit must—

1. have an R_W of not less than 50; and
2. provide satisfactory insulation against impact sound; and
3. not incorporate a duct which reduces the R_W of the wall to less than 50.

(2) A wall satisfies (1)(a) and (b) if it is—

1. in accordance with (3); or
2. for other than masonry, in 2 or more separate leaves without rigid mechanical connection except at their periphery; or
3. identical to a prototype that is no less resistant to the transmission of impact sound when tested in accordance with NT Specification 29 than a wall listed in (3).

(3) For the purposes of (2)(a) and (c), the construction of walls to reduce the transmission of impact sound must be as follows:

1. Cavity brickwork: two leaves of 90 mm brick masonry with—
   1. all joints filled solid with mortar; and
   2. an air space not less than 40 mm between the leaves; and
   3. the leaves connected only by ties in accordance with AS 3700.
2. Single leaf brickwork: 110 mm thick brick masonry with—
   1. each face rendered 13 mm thick; and
   2. 50 mm x 12 mm thick timber battens at not more than 610 mm centres fixed to each face but not recessed into the render; and
   3. one layer of 12 mm thick softboard nailed to the battens; and
   4. 6 mm thick medium density hardboard adhesive-fixed to the softboard.
3. Concrete blockwork: 190 mm thick concrete block masonry with—
   1. each face of the blocks fitted with 50 mm x 50 mm timber battens, spaced at not more than 610 mm centres, screw-fixed into resilient plugs with rubber inserts; and
   2. the space between the battens completely filled with mineral or glass wool blanket or batts not less than 50 mm thick; and
   3. the outer face of the battens finished with plasterboard not less than 10 mm thick or other material with a mass per unit area not less than 7.3 kg/m².

If a soil or waste pipe, including a pipe that is embedded in or passes through a floor, serves or passes through more than one sole-occupancy unit—

1. the pipe must be separated from the rooms of any sole-occupancy unit by construction with an R_W not less than—
   1. 45 if the adjacent room is a habitable room (other than a kitchen); or
   2. 30 if the adjacent room is a kitchen or any other room; and
2. a door or panel provided access to the pipe must not open into any habitable room (other than a kitchen); and
3. an access door or panel in any other part must be firmly fixed so as to overlap the frame or rebate of the frame by not less than 10 mm, be fitted with a sealing gasket along all edges and be constructed of—
   1. wood, particleboard or blockboard not less than 38 mm thick; or
   2. compressed fibre reinforced cement sheeting not less than 9 mm thick; or
   3. other suitable material with a mass per unit area not less than 24.4 kg/m².

A flexible coupling must be used at the point of connection between the service pipes in a building and any circulating or other pump.

In addition to NT F7D5, a wall separating a sole-occupancy unit in a Class 9c building from a kitchen or laundry must—

1. for other than masonry, be two or more separate leaves without rigid mechanical connection except at their periphery; or
2. be identical with a prototype that is no less resistant to the transmission of impact sound when tested in accordance with NT Specification 29 than a wall listed in NT S28C3.