Part F7 Sound transmission and insulation

Part F7 addressessound and its impact on health and amenity, but only within Class 2, Class 3 and Class 9c buildings. Reasons why it does not cover sound emanating from outside the building include:

• builders, etc have little control over external sound, which is usually intermittent during daylight hours when the background ambience sound within the building is greater; and
• sound generated within a building is more likely to pass through walls and fittings, and cannot be controlled by simply closing a window. Such sounds can be more intrusive and disruptive to occupants.

To achieve F7O1 in a Class 2, Class 3 and Class 9c buildings, sound transmission must be minimised through a building element that separates:

• sole-occupancy units;
• a sole-occupancy unit and a common space; or
• a sole-occupancy unit from parts of the building with a different classification.

Because of its emphasis on building elements which separate sole-occupancy units and sole-occupancy units and common spaces and parts of the building with a different classification, F7F1 does not cover building elements which separate sole-occupancy units from the outside of a building, and therefore does not cover:

• sound generated outside a building; or
• sound escaping from a building and re-entering via an external element.

F7P1 applies to Class 2 and 3 buildings and relates to the floor between sole-occupancy units, sole-occupancy units and specified spaces, and sole-occupancy units and parts of a different classification. It covers both airborne and impact generated sound. F7P1 covers sound transmission through floors from a number of specified spaces. A list is included with the additional words ‘or the like’. An example of a floor separating sole-occupancy units from parts of a different classification, would be a floor separating ground floor shops from an apartment level above.

F7P2 applies to Class 2 and 3 buildings and relates to the walls including services and their penetrations, between sole-occupancy units, sole-occupancy units and specified spaces, and sole-occupancy units and parts of a different classification. It covers both airborne and impact generated sound. F7P2(a)(ii) covers sound transmission through walls from a number of specified spaces. A list is included with the additional words ‘or the like’. An example of a wall separating sole-occupancy units from parts of a different classification, would be a wall in a building between shops and hotel rooms.

Unlike F7P1, impact generated sound is only a consideration for walls separating a bathroom, kitchen, sanitary compartment or laundry in one sole-occupancy unit from a habitable room (other than a kitchen) in an adjoining unit, and for walls separating a sole-occupancy unit from a plant room or lift shaft..

F7P3 relates to floors between sole-occupancy units in Class 9c buildings. It covers airborne and impact generated sounds between units located above one another. It does not cover sound transmission through floors from common spaces, such as a common corridor, laundry or entertainment area.

F7P4 only applies to Class 9c buildings.

For airborne sound, F7P4 relates to the insulation of walls:

• between sole-occupancy units; and
• between sole-occupancy units and a kitchen, bathroom, sanitary compartment (not being an associated ensuite), laundry, plant room or utilities room, including the effects of services and penetrations.

For impact generated sound, F7P4 relates to the insulation of walls between sole-occupancy units and a kitchen or laundry.

F7V1 is a means of verifying whether a floor achieves the requirements of F7P1 and in minimising the transmission of airborne and impact generated sound through the floor. It only applies to Class 2 and 3 buildings.

It is not compulsory for a designer to use F7V1. The designer has the choice of using:

• F7V1 to verify that a proposal achieves F7P1; 
• the Deemed-to-Satisfy Provisions of Part F7; or
• another means of verifying that F7P1 and will be achieved.

If F7V1 is used to verify compliance, when tested on site the floor must have a weighted standardised level difference with spectrum adaptation term (DnT,w + Ctr) not less than 45, and a weighted standardised impact sound pressure level with spectrum adaptation term (LnT,w) not more than 62.

DnT,w is a measure of airborne sound insulation, similar to Rw. Ctr is a spectrum adjustment factor which adjusts for low frequency sound levels. Ctr has been chosen in recognition of the problems caused by the high bass frequency outputs of modern home theatre systems and music reproduction equipment used by occupants of Class 2 and 3 buildings.

The DnT,w and Ctr must be determined in accordance with AS/NZS ISO 717.1. AS/NZS ISO 717.1 outlines how to use test results to determine the DnT,w and Ctr of a building element. The test results must be obtained by testing the floor in accordance with ISO 140-4. ISO 140-4 is the method for testing the airborne sound insulation of building elements in the field.

LnT,w is a measure of impact sound insulation. The lower the LnT,w, the better the floor’s impact sound insulation rating.

The LnT,w must be determined in accordance with AS ISO717.2. This document outlines how to use test results to determine the LnT,w and CI of a building element. The test results must be obtained by testing of the floor in accordance with ISO 140-7. ISO 140-7 is the method for testing the impact sound insulation of building elements in the field.

F7V2 is a means for verifying if a wall complies with the requirements of F7P2(a) and in minimising the transmission of airborne sound through the wall. As with F7V1 it only applies to Class 2 and 3 buildings.

It is not compulsory for a designer to use F7V2. The designer has the choice of using:

• F7V2 to verify that a proposal achieves F7P2(a), and;
• the Deemed-to-Satisfy Provisions of Part F7; or
• another means of verifying that F7P2(a) and will be achieved.

If F7V2 is used to verify compliance, when tested on site the wall must have a weighted standardised level difference with spectrum adaptation term (DnT,w + Ctr) not less than 45.

DnT,w is a measure of airborne sound insulation, similar to Rw. Ctr is a spectrum adjustment factor which adjusts for low frequency sound levels. Ctr has been chosen in recognition of the problems caused by the high bass frequency outputs of modern home theatre systems and music reproduction equipment used by occupants of Class 2 and 3 buildings.

The DnT,w and Ctr must be determined in accordance with AS/NZS ISO 717.1. AS/NZS ISO 717.1 outlines how to use test results to determine the DnT,w and Ctr of a building element. The test results must be obtained by testing the wall in accordance with ISO 140-4.ISO 140-4 is the methodfor testing the airborne sound insulation of building elements in the field.

Unlike F7V1, the requirements differ depending on the location of the wall. Walls separating sole-occupancy units require aDnT,w + Ctr not less than 45. Walls separating sole-occupancy units and areas such as plant rooms, lift shafts, stairways, public corridors, public lobbies or the like, or parts of a different classification, must have a DnT,w not less than 45. Ctr does not apply in these instances, as the walls separate units from areas that are not likely to produce low frequency noise, which Ctr accounts for.

Door assemblies are permitted in walls between sole-occupancy units and public corridors, stairways or the like, providing the door assembly has a DnT,w not less than 25. Door assemblies are also permitted in walls between sole occupancy units, providing the door assembly has the same level of sound insulation as the wall i.e. DnT,w + Ctr not less than 45.

There is no verification method for determining compliance with F7P2(b). F7P2(b) outlines the impact generated sound insulation requirements for walls. Therefore, in this instance the options for compliance are:

• the Deemed-to-Satisfy Provisions of Part F7 i.e. discontinuous construction; or
• another means of verifying that F7P2(b) will be achieved.

F7V3 is a means of verifying whether a floor achieves the requirements of F7P3 and F7P4 in minimising the transmission of airborne and impact generated sound through the floor. It only applies to Class 9c buildings. It is not compulsory for a designer to use F7V3. The designer has the choice of using:

• F7V3 to verify that a proposal achieves F7P3 and F7P4;
• the Deemed-to-Satisfy Provisions of Part F7; or
• another means of verifying that F7P3 and F7P4 will be achieved.

If F7V3 is used to verify compliance, when tested on site the floor must have a weighted standardised level difference (DnT,w) not less than 40, and a weighted standardised impact sound pressure level (LnT,w) not more than 62.

DnT,w is a measure of airborne sound insulation, similar to Rw.

The DnT,w must be determined in accordance with AS/NZS ISO 717.1. AS/NZSISO 717.1 outlines how to use test results to determine the DnT,w of a building element. The test results must be obtained by testing the floor in accordance with ISO 140-4. ISO140-4 is the method for testing the airborne sound insulation of building elements in the field.

LnT,w is a measure of impact sound insulation. The lower the LnT,w, the better the floor ’s impact sound insulation rating.

The LnT,w must be determined in accordance with AS ISO717.2. This document outlines how to use test results to determine the LnT,w of a building element. The test results must be obtained by testing of the floor in accordance with ISO 140-7. ISO 140-7 is the method for testing the impact sound insulation of building elements in the field.

The LnT,w must be determined in accordance with AS ISO717.2. This document outlines how to use test results to determine the LnT,w of a building element. The test results must be obtained by testing of the floor in accordance with ISO 140-7. ISO 140-7 is the method for testing the impact sound insulation of building elements in the field.

F7V4 is a means for verifying if a wall complies with the requirements of F7P4(1)(a) and (2) in minimising the transmission of airborne sound through the wall. It only applies to Class 9c buildings.

It is not compulsory for a designer to use F7V4. The designer has the choice of using:

• F7V4 to verify that a proposal achieves F7P4(1)(a) and (2);
• the Deemed-to-Satisfy Provisions of Part F7; or
• another means of verifying that F7P4(1)(a) and (2) will be achieved.

If F7V4 is used to verify compliance, when tested on site the wall must have a weighted standardised level difference with spectrum adaptation term (DnT,w) not less than 40 determined in accordance with AS/NZS ISO 717.1.

Throughout the Part F7 Deemed-to-Satisfy Provisions, some forms of construction are required to have an Rw or Rw + Ctr. Rw and Ctr must be:

• determined under AS/NZSISO717.1 using laboratory measurements; or
• in compliance with Specification 28.

Rw is a measure of airborne sound insulation. Ctr is a spectrum adjustment factor which adjusts for low frequency sound levels. Ctr has been chosen in recognition of the problems caused by the high bass frequency outputs of modern home theatre systems and music reproduction equipment used by occupants of Class 2 and 3 buildings.

The Rw and Ctr must be determined in accordance with AS/NZS ISO 717.1.

In F7D5(1) floors separating certain areas are required to have an Ln,w. F7D4(1) outlines that the L_n,w must be:

• determined under AS ISO 717.2 using laboratory measurements; or
• in compliance with Specification 28.

Ln,w is a measure of impact sound insulation. The types of impact generated noise passing through floors that the requirements are aimed at minimising are noise associated with footsteps and moving of furniture.

F7D4(2)(a) requires walls of Class 2 and 3 buildings required to have an impact sound insulation rating to be of discontinuous construction. This term is defined in F7D4(3) and applies to all of Part F7 as well as Specifications 28 and 29.

F7D4(2)(b) requires walls of a Class 9c building required to have an impact sound insulation rating to:

• for other than masonry, consist of at least two separate leaves that do not have any rigid mechanical connection except at the periphery. (The reason for not allowing rigid connection is to reduce the transmission of impact sound to the sleeping area); or
• be identical with a prototype having at least the same resistance to impact sound as a wall complying with Specification 28 (see clauses S28C4 to S28C7).

F7D4(3) sets out a definition of discontinuous construction. The definition applies to the whole of Part F7 (including Specifications 28 and 29) and is a wall having a cavity of at least 20 mm between 2 separate leaves, and:

• for masonry, only be connected with resilient wall ties (these are a particular type of wall tie and are sometimes referred to as acoustic wall ties); and
• for other than masonry, other than at the periphery, have no mechanical linkage between the leaves. A staggered stud wall is not discontinuous construction.

F7D5 contains requirements for Class 2, 3 and 9c buildings.

For Class2 and 3 buildings, a floor requires both airborne (R_w + C_tr) and impact sound insulation (L_n,w) if it separates:

• sole-occupancy units;
• a sole-occupancy unit from a plant room, lift shaft, stairway, public corridor, public lobby or the like; or
• parts of a different classification.

For Class 9c buildings, a floor requires airborne sound insulation if it separates sole-occupancy units.

The requirements differ between Class 2 and 3 buildings, and Class 9c buildings. This is due to sole-occupancy units in Class 2 and 3 buildings being ‘noisier’ than sole-occupancy units in Class 9c buildings. The reasons include the presence of televisions, stereos and DVDs and activities that may be conducted in Class 2 and 3 buildings. Therefore, C_tr and impact sound insulation only apply to Class 2 and 3 buildings. Also, the level of airborne sound insulation required in Class 9c buildings is less.

F7D6(1) and (2) apply to Class 2 and 3 buildings. F7D6(1) covers walls separating sole-occupancy units, and walls separating sole-occupancy units and certains paces. F7D6(2) applies to a door assembly in a wall that separates a sole- occupancy unit from a common area. F7D6(3) and (4) apply to Class 9c buildings. F7D6(3) applies to walls which separate sole-occupancy units and sole-occupancy from certain spaces. F7D6(4) applies to a wall that separates a sole-occupancy unit from a kitchen or laundry. F7D6(5) and (6) contain additional requirements for sound insulated walls.

As with the requirements for floors, the requirements for walls differ between Class 2 and 3 buildings, and Class 9c buildings. This is due to sole-occupancy units in Class 2 and 3 buildings being ‘noisier’ than sole-occupancy units in Class 9c buildings. The reasons include the presence of televisions, stereos and DVDs and activities that may be conducted in Class2 and 3 buildings. Therefore, Ctr only applies to Class 2 and 3 buildings. Also, the level of airborne sound insulation required in Class 9c buildings is less.

F7D6(1) outlines airborne and impact sound insulation requirements for walls. The airborne sound requirements apply to walls separating sole-occupancy units and a sole-occupancy unit from a plant room, lift shaft, stairway, public corridor, public lobby or the like, or parts of a different classification. For walls separating sole-occupancy units, the wall must have a Rw + Ctr not less than 50. For walls separating a sole-occupancy unit from a plant room, lift shaft, stairway, public corridor, public lobby or the like, or parts of a different classification, the wall must have a Rw not less than 50. For walls separating habitable areas (excluding a kitchen) in one sole-occupancy unit from a bathroom, laundry, kitchen or sanitary compartment in an adjoining unit, the wall must be discontinuous construction. For the purpose of the BCA, discontinuous construction is a wall having a minimum 20 mm cavity between 2 separate leaves, with:

• for masonry, where wall ties are required to connect leaves, the ties are of the resilient type; and
• for other than masonry, there is no mechanical linkage between leaves, except at the periphery.

Mechanical linkage at the periphery is referring to the connection of the wall to the floor/roof and adjoining walls such as an externalwall etc. A staggered stud wall with common top/bottom plates is not considered to be discontinuous construction.

F7D6(2) provides a concession for a door assembly located in a wall that separates a sole-occupancy unit from public corridor or the like. The door requires an R_w of not less than 30 whereas the wall requires Rw of not less than 45. This concession does not apply to a door assembly in a wall separating sole-occupancy units. In this case the door assembly would need to meet the same requirements for the wall, i.e. Rw + Ctr not less than 50.

F7D6(3) applies to Class 9c buildings and covers sound transmission through sole-occupancy units from certain adjoining rooms and spaces. The list of adjoining rooms and spaces does not include the words ‘or the like’ because it is intended to be specific to only those areas.

The list of other spaces in F7D6(3) does not include stairways, public corridors, hallways, etc. The reason is that aged care buildings are to be provided with a level of sound insulation around the resident bedroom/sleeping areas to ensure a level of privacy, but still allow the residents to be reassured they are not alone. If the R_w of the wall is too high it may create a feeling of isolation for the residents and this can be detrimental to their well being. Being able to hear sounds that are outside their bedroom provides reassurance that assistance is available. The walls of sole-occupancy units prescribed in F7D6(3) must be at least Rw 45.

F7D6(4) applies to Class 9c buildings and deals with reducing the level of impact sound through the walls of the sole- occupancy units from adjoining kitchens and laundries. To comply with F7D6(4), it is necessary for the wall to have an Rw not less than 45 (as required by F7D6(3)) and:

• for other than masonry, consist of at least two separate leaves that do not have any rigid mechanical connection except at the periphery (the reason for not allowing rigid connection is to reduce the transmission of impact sound to the sleeping area); or
• be identical with a prototype having at least the same resistance to impact sound as a wall complying with Specification 28.

F7D6(5) and (6) require sound insulated walls to extend to either the roof/floor above or a ceiling that provides the required level of sound insulation. This is to ensure that there is no space above the wall which provide a flanking path for sound to travel through.

F7D7 details separation requirements for services. The requirements only apply to services which pass through more than one sole-occupancy unit or are located in a wall or floor cavity which separates sole-occupancy units. F7D7 does not apply if the pipe is only located in a single unit, or any part of a Class 2, 3 or 9c building which is not part of a sole- occupancy unit.

The R_w + C_tr valuesdo not take account of the inherent acoustic properties of a pipe material.

F7D8 requires flexible couplings at connection points to or from a pump to minimise vibration and any consequent sound transmission along the piping.