BUILDING STANDARDS DIVISION
EXAMPLE CONSTRUCTIONS
AND GENERIC INTERNAL
CONSTRUCTIONS
FOR USE WITH SECTION 5: NOISE OF THE
TECHNICAL HANDBOOKS
CONTENTS
Page
Introduction
Status of document
Background
Aims
3
Example Constructions
Section 1 – Example Constructions
1.a Design of Example Constructions
1.b Separating wall details – links to wall types
1.c Separating floor details – links to floor types
4
Section 2 – Design and specification considerations
2.a Design and specification
2.b On-site construction practices – separating walls
2.c On-site construction practices – separating floors
10
3.a
3.b
3.c
3.d
3.e
Section 3 – Component specification and acoustic performance
requirements
Wall ties for blockwork cavity walls
Bonded Resilient Covers (BRC’s) over isolated screeds
Floating Floor Treatments (FFT’s)
Resilient ceiling bars
Downlighters (recessed lighting)
Generic Internal Constructions
4.a Internal walls and intermediate floors
4.b Internal wall details
4.c Intermediate floor details
13
17
Annex A – Explanation of terms
21
Annex B – Laboratory test procedures for building products and
components for manufacturers
24
B1
General requirements for the selection of Bonded Resilient Coverings
(BRC’s) and Floating Floor Treatments (FFT’s)
25
B2
Determination of the acoustic performance of Bonded Resilient Coverings
(BRC’s) used with concrete core floors
25
B3
Determination of the acoustic performance of requirements of Floating
Floor Treatments (FFT’s) used with timber joist or lightweight frame core
floors
27
B4
Determination of the acoustic performance of resilient ceiling bars
29
B5
Determination of the influence on the acoustic performance of timber
separating floors due to the presence of downlighters (recessed lighting)
31
B6
Determination of the acoustic performance of downlighters and recessed
lighting used with timber core floors
34
Version
Date
1.0
1 October 2010
Notes
New Document
2
INTRODUCTION
Status of this document
This document provides guidance on one way of meeting some of the requirements
of the functional standards set out in Regulation 9 of the Building (Scotland)
Regulations 2004, as amended. However, it is acceptable to propose alternative
solutions provided they fully satisfy the functional standards.
Background
A reduction in sound transmission passing through a separating wall or floor is
achieved by limiting airborne sound, such as that from speech or television, and
impact sound such as that from footsteps by providing sound insulation measures.
Sound insulation involves a “system approach” using a combination of products and
components. The wide range of acoustic product testing and the logarithmic
approach for sound insulation performance does not lend itself to a straightforward
design process. A non-acoustician will find this complex. Past experience has shown
that one of the most common causes of failure to meet the sound insulation
performance levels was the specification or subsititution of unsuitable products.
Aims
The main aim of this document is to provide examples of the most commonly used
separating wall, separating floor, internal wall and intermediate floor constructions.
These examples offer a prepared solution to meeting certain aspects of Standard 5.1
and Standard 5.2. When built correctly, and taking into account the flanking
elements, they should meet the sound performance levels given in 5.1.2 and 5.2.1 of
the Technical Handbooks.
Annex B of this document contains the relevant test information sought by
manufactures to demonstrate that their products are suitable to be used in an
Example Construction specification.
3
EXAMPLE CONSTRUCTIONS
SECTION 1
1.a
Design of Example Constructions
The Example Constructions have been designed with the following in mind:
x to reduce horizontal impact sound transmission through separating wall
constructions from sound caused by switches, inserting plugs into sockets or
cupboard doors closing;
x to provide suitable measures to reduce impact sound transmission through
separating floor constructions which incorporate wood based floor coverings;
x to reduce flanking sound transmission through other construction elements
which are not part of the separating wall or floor, such as inner leafs of
external walls.
The common factors which are illustrated in each detail are:
x core wall or floor construction;
x wall linings;
x isolating, resilient or floating floor layers;
x interaction with other building elements;
- junction with the external wall
- junction with separating wall or floor
- junction for the ground floor
- junction with internal walls or floors
- junction with the ceiling and roof space
x lining details for vertical soil vent pipes and wall mounted service
penetrations;
x separating walls between a dwelling and a common area (e.g. stairway for
flats and maisonettes).
Other requirements of the Scottish building regulations which are not illustrated by
these details, but which should be considered by the designer include:
x structure;
x fire resistance and flame spread;
x damp-proofing arrangements;
x precipitation;
x ventilation;
x thermal performance of elements;
x thermal bridging and air leakage.
4
1.b
Separating wall details
SEPARATING WALLS
Wall Type 1
Masonry solid walls
(dense blockwork) for use
in attached houses, flats
and maisonettes
DETAILS
1.00
DENSE BLOCK SOLID WALL
1.01
Isometric and construction detail
1.02
External wall junction
1.03
Separating floor junction: Floor Type 2A
1.04
Separating floor junction: Floor Type 2B
1.05
Ground floor junction: Floating Floor Treatment
(FFT)
1.06
Ground floor junction: isolated screed
1.07
Ceiling and roof junction
1.08
Separating wall: dwelling to common area
2.00
DENSE BLOCK CAVITY WALL
2.01
Isometric and construction detail
2.02
External wall junction
2.03
Separating floor junction: Floor Type 2A
2.04
Separating floor junction: Floor Type 2B
2.05
Ground floor junction
2.06
Internal floor junction: floor joists on hangers
2.07
Internal floor junction: floor joists built-in
2.08
Ceiling and roof junction
2.09
Separating wall: dwelling to common area
Wall Type 2
Masonry cavity walls
(dense blockwork) for
use in attached houses,
flats and maisonettes
5
SEPARATING WALLS
DETAIL
3.00
TIMBER FRAME TWIN STUD WALL
3.01
Isometric and construction detail
3.02
External wall junction
3.03
Separating floor junction: Floor Type 3A
Wall Type 3
3.04
Separating floor junction: Floor Type 3B
Timber frame twin stud
walls (with and without
sheathing) for use in
attached houses, flats
and maisonettes
3.05
Ground floor junction
3.06
Ground floor junction: raft foundation
3.07
Internal wall junction
3.08
Internal floor junction
3.09
Ceiling and roof junction
3.10
Services and sockets
3.11
Separating wall: dwelling to common area
4.00
METAL FRAME TWIN STUD WALL
4.01
Isometric and construction detail
4.02
External wall junction: metal stud framing
4.03
External wall junction: in-situ concrete framing
Wall Type 4
4.04
Separating floor junction: Floor Type 1A
Metal frame twin stud
walls for use in attached
metal frame houses and
in-situ concrete frame,
flats and maisonettes
4.05
Separating floor junction: Floor Type 1B
4.06
Ground floor junction
4.07
Ground floor junction: raft foundation
4.08
Internal wall junction
4.09
Internal floor junction
4.10
Ceiling and roof junction
4.11
Services and sockets
4.12
Separating wall: dwelling to common area
6
1.c
Separating floor details
SEPARATING FLOORS
Floor Type 1A
In-situ concrete slab with
isolating screed and
Bonded Resilient Cover
(BRC)
DETAIL
5.00
IN-SITU CONCRETE: with isolated screed
and Bonded Resilient Cover (BRC)
5.01
Isometric and construction detail
5.02
Isolated screed and Bonded Resilient Cover
(BRC)
5.03
Ceiling treatment
5.04
External wall junction: metal stud inner leaf
5.05
External wall junction: dense block inner leaf
5.06
Separating wall junction: Wall Type 4
5.07
Services: vertical soil vent pipes (SVP's)
6.00
IN-SITU CONCRETE: with Floating Floor
Treatment (FFT)
6.01
Isometric and construction detail
6.02
Floating Floor Treatment (FFT)
6.03
Ceiling treatment
6.04
External wall junction: metal stud inner leaf
6.05
External wall junction: dense block inner leaf
6.06
Separating wall junction: Wall Type 4
6.07
Services: vertical soil vent pipes (SVP's)
Floor Type 1B
In-situ concrete slab with
Floating Floor Treatment
(FFT)
7
SEPARATING FLOORS
Floor Type 2A
Precast concrete slab
with isolating screed and
bonded resilient cover
Floor Type 2B
Precast concrete slab
with floating floor
treatment
DETAIL
7.00
PRECAST CONCRETE SLAB: with isolated
screed and Bonded Resilient Cover (BRC)
7.01
Isometric and construction detail
7.02
Isolated screed and Bonded Resilient Cover
(BRC)
7.03
Ceiling treatment
7.04
External wall junction: dense block inner leaf
7.05
Separating wall junction: Wall Type 1
7.06
Separating wall junction: Wall Type 2
7.07
Services: vertical soil vent pipes (SVP's)
8.00
PRECAST CONCRETE SLAB: with Floating
Floor Treatment (FFT)
8.01
Isometric and construction detail
8.02
Floating Floor Treatment (FFT)
8.03
Ceiling treatment
8.04
External wall junction: dense block inner leaf
8.05
Separating wall junction: Wall Type 1
8.06
Separating wall junction: Wall Type 2
8.07
Services: vertical soil vent pipes (SVP's)
8
SEPARATING FLOORS
Floor Type 3A
Timber frame floor with
solid joists
DETAIL
9.00
TIMBER FRAME FLOOR: with solid joists
9.01
Isometric and construction detail
9.02
Floating Floor treatment (FFT)
9.03
Ceiling treatment
9.04
External wall junction: timber frame inner leaf
9.05
Separating wall junction: Wall Type 3
9.06
Internal wall junction: loadbearing
9.07
Internal wall junction: non-loadbearing
9.08
Services: vertical soil vent pipes (SVP's)
10.00
TIMBER FRAME FLOOR: with engineered Ijoists
10.01 Isometric and construction detail
10.02 Floating Floor Treatment (FFT)
Floor Type 3B
Timber frame floor with
engineered I-joists
10.03 Ceiling treatment
10.04 External wall junction: timber frame inner leaf
10.05 Separating wall junction: Wall Type 3
10.06 Internal wall junction: loadbearing
10.07 Internal wall junction: non-loadbearing
10.08 Services: vertical soil vent pipes SVP's
9
SECTION 2
DESIGN AND SPECIFICATION CONSIDERATIONS
2.a
Design and specification
At the design stage of any development the design and specification are important
as in the past this has found to be the most common cause of sound performance
failure.
Design and specification consideration should include:
x the minimum block density;
x the Floating Floor Treatment (FFT) achieves the performance requirements
in 3c;
x the resilient ceiling bar achieves the performance requirements in 3d;
x the wall tie type for blockwork cavity separating walls should always be wall
tie Type A, see 3a;
x the minimum cavity width or floor cavity depth;
x the minimum gypsum board density (to achieve a high enough level of mass);
x the use of mineral wool based boards (as they have acoustic absorption
properties) and not rigid insulation boards (as they have very low acoustic
absorption properties).
2.b
On-site construction practices (separating walls)
Generally, the approved design and specification should be adhered to and the
substitution of products should be avoided.
Past experience has shown the following on-site construction practices will assist in
achieving the sound insulation performance;
Wall Type 1 - Dense block solid wall
x using a dense block as specified;
x laying the 215 mm block full width on its side;
x fully filling perpends and bed joints with mortar;
x achieving external wall inner leaf continuity with the separating wall;
x installing independent metal frame studs at a minimum 30 mm offset from the
blockwork face;
x fully filling the metal frame stud width and height with quilt insulation.
Wall Type 2 - Dense block cavity wall
x using a dense block as specified;
x fully filling perpends and bed joints with mortar;
x using Wall Tie Type A in the separating wall leafs, see 3a;
x keeping the wall ties free of mortar and debris at the base of the wall cavity (to
help prevent bridging of the cavity wall leafs);
10
x
x
achieving a minimum 75 mm cavity width;
scratching the wet render (to increase the mechanical bond for the dab and
gypsum based board).
Wall Type 3 - Timber frame twin stud wall
x achieving the minimum cavity width between linings;
x achieving a minimum of 50 mm between sheathed stud walls;
x fully covering the wall face of the stud bay with quilt insulation;
x staggering the joints of gypsum board linings;
x achieve the minimum gypsum board density;
x avoid spanning joists into the wall cavity (to prevent bridging of the twin frame)
x using a rigid cavity stop fixed to one frame only (to prevent bridging of the twin
frame).
Wall Type 4 - Metal frame twin stud wall
x building a 200 mm minimum cavity width between linings;
x fully covering the wall face of the stud bay with quilt insulation;
x staggering the joints of gypsum board linings;
x achieve the minimum gypsum board density;
x using a rigid cavity stop fixed to one frame only (to prevent bridging of the twin
frame).
2.c
On-Site construction practices (Separating Floors)
Generally, the approved design and specification should be adhered to and the
substitution of products should be avoided.
Past experience has shown the following on-site construction practices will assist in
achieving the sound insulation performance;
Isolated screeds
x installing both isolating layers;
x isolating the screed (to prevent the screed bridging the core slab);
x isolating the screed (to prevent the screed bridging the perimeter wall, wall
linings and skirting) ;
x achieving the minimum depth of 65 mm sand:cement screed.
Bonded Resilient Covers (BRC)
x using a resilient cover that achieves the performance requirements in 3b.
Floating Floor Treatments (FFT)
x using the minimum FFT depth specified;
x using a FFT that achieves the performance requirements in 3c;
x installing the perimeter flanking strip (to isolate flooring boards from skirtings
and wall linings);
x using the correct screw length (to prevent screws or nails bridging the resilient
layer);
x taking care installing services (to prevent them bridging the resilient layer).
11
Suspended ceiling treatments
x using a metal frame ceiling where required;
x building to the correct ceiling void depth;
x achieving the minimum mass per unit area of the ceiling board.
Resilient ceiling bars
x using resilient ceiling bar that achieve the performance requirements in 3d;
x using the correct screw length (to prevent the ceiling board screw fixings
touching the joist).
12
SECTION 3
COMPONENT SPECIFICATION AND ACOUSTIC PERFORMANCE
REQUIREMENTS
3.a
Wall ties for blockwork cavity walls
Specification of the correct wall tie is important. A wall tie will transmit sound and can
affect the sound insulation performance. For example if the wall tie is too thick or too
stiff, or a build up of mortar or debris on the wall tie has been allowed to form, this
will increase sound transmission leaf to leaf (acoustic bridging). Therefore, it is
important that wall ties and cavities are protected during construction and kept clear
of mortar or debris. Particular attention should be paid to Section 1: Structure of the
Technical Handbooks.
Separating walls – wall tie Type A
All wall ties used in separating walls involving cavity blockwork should be tie Type A.
Tie Type A should achieve an appropriate measured dynamic stiffness for the cavity
width. The specification for wall ties dynamic stiffness, KXmm in MN/m with a cavity
width of X mm and n ties/m2 is n.kXmm<4.8 MN/m3. A wall tie manufacturer will be
able to provide product specification details which achieve the stiffness for wall tie
Type A.
External walls - wall tie Type A or B
Wall ties used in external blockwork cavity walls can be tie Type A (as above) or tie
Type B (depending on strength requirements), which have an appropriate measured
dynamic stiffness for the cavity width. The specification for wall ties of dynamic
stiffness, KXmm in MN/m with a cavity width of X mm and n ties/m2 is n.kXmm<4.8
MN/m3 (tie Type A) or <113 MN/m3 (tie Type B). A wall tie manufacturer will be able
to provide product specification details to achieve these requirements for tie Type A
or tie Type B for external walls.
3.b
Bonded Resilient Covers (BRC’s) over an isolated screed
A resilient cover is a thin resilient layer used below a floor covering, which can be
bonded to a concrete floor or to the surface of an isolated screed. When bonded it is
referred to as a Bonded Resilient Cover (BRC). The use of a BRC does not
generally affect airborne transmission but can reduce impact sound transmission.
Isolated screed
The resilient layer can also be used as an isolating layer underneath a
screed, as in floor detail 1A and 2A, to improve airborne and impact
sound transmission. However, the isolating layer on its own is not
sufficient to repeatedly achieve the required impact performance against
13
impact noise such as footsteps. There has been an increase in the use
of wood based floor coverings, such as laminate flooring, laid directly on
a screed finish without a resilient layer (underlay, between a wood based
floor covering and a screed). This will increase sound transmission into
the dwelling below, therefore a BRC should be used and cover the entire
floor surface of the room.
Where BRC’s are used for concrete core floors they should be tested with a wood
based floor covering laid over the resilient layer. This would provide a more realistic
performance for how these components may perform for impact sound insulation in
buildings with hard floor finishes.
The BRC used in concrete core floors should:
x be tested for impact performance in an acoustic laboratory, as outlined in
Annex B; and
x achieve the required minimum sound insulation performance as described in
the table below.
Minimum performance requirements of BRC’s
used with concrete core floors [1- 3]
Impact ÷Lw
17 dB
Notes:
1) The above performance requirement is based on a resilient floor
covering which has been tested in a laboratory in accordance with
Annex B under a wood based floor covering. Any material adopted for
use in the Example Constructions should also have been tested
under a wood based floor covering.
Testing directly onto the resilient cover will lead to an exaggerated
performance which does not reflect its true performance under a
wood based floor covering when built.
2) Annex B outlines the laboratory test requirements for resilient floor
coverings with concrete core floors.
3) BRC’s should only be used with concrete core floors.
3.c
Floating Floor Treatments (FFT’s)
A floating floor treatment (FFT) is a timber floating floor system, normally timber,
which may utilise battens, cradles or a platform base. All of these use a resilient
layer to provide isolation from the base floor and adjacent wall elements. FFT’s can
increase the airborne and impact performance for both concrete core floors and
lightweight frame floors (such as timber joist separating floors).
FFT’S are referred to in terms of FFT1, FFT2 or FFT3, which relates to their
structure type, design depth and their acoustic performance. These FFT’s apply to
resilient battens and cradle systems which support a timber based tongue and
grooved (t&g) floor board. All FFT’s require acoustic isolation flanking strips at the
room perimeter. The flanking strip should be installed such that it isolates the floor
board edge form the perimeter wall, wall linings and skirtings. Further descriptive
14
information relating to the relative FFT is provided in each Example Construction.
FFT1 and FFT3 - the composite resilient batten used is composed of a
timber batten with a pre-bonded, continuous resilient material to provide
isolation between the flooring surface layers and floor base or core.
FFT2 - the cradle / saddle is used as an intermediate support system (with
a resilient layer base, either pre-bonded or already integral) using levelling
packer pieces to support a timber batten, isolating it from the floor base.
Cradles should not be used on timber joist floors unless the supporting deck has
sufficient stiffness and strength properties to cope with concentrated point loads.
The incorporation of Ctr (measurement criteria for low frequency noise) within the
laboratory test requirements for FFT’s for timber joist floors or lightweight frame
floors will enhance the low frequency performance of these structures.
The FFT’s used in concrete core floors, timber joist or lightweight frame core floors
should:
x be tested in an acoustic laboratory, as outlined in Annex B; and
x achieve the required airborne and impact sound insulation performance as
described in the tables below.
Minimum performance requirements of FFT’s
used with concrete core floors
FFT1, FFT2 and FFT3 [1]
Airborne ÷Rw
Impact ÷Lw
5 dB
22 dB
Note:
1) Annex B outlines the laboratory test requirements for FFT’s on concrete
core floors.
Minimum performance requirements of FFT’s
used with timber joist or lightweight frame floors
FFT1 [1]
Airborne ÷Rw
Airborne ÷Rw + Ctr
Impact ÷Lw
17 dB
13 dB
16 dB
Note:
1) Annex B outlines the laboratory test requirements for FFT’s when used
with timber joist or lightweight frame floors
3.d
Resilient ceiling bars
Resilient ceiling bars are generally metal based and can increase both airborne and
impact sound insulation performance.
Resilient ceiling bars are used to support ceiling board linings and mounted
perpendicular to the joist span for timber frame and lightweight frame floors. They
can improve both the airborne and the impact performance of the separating
15
lightweight frame floor.
Resilient ceiling bars vary in thickness and are used to support ceiling board linings
and mounted perpendicular to the joist span. To obtain the best acoustic
performance for both airborne and impact sound insulation the ceiling board fixings
into the resilient bar should not come into direct contact with the joists. Care should
be taken to ensure the correct screw length is used for fixing.
The incorporation of Ctr within the laboratory test requirements for resilient ceiling
bars for timber joist floors or lightweight frame floors will enhance the low frequency
performance of these structures.
The resilient ceiling bars for timber joist floors should:
x be tested in an acoustic laboratory, as outlined in Annex B; and
x achieve the required impact sound insulation performance as described in the
table below
Minimum performance requirements
of resilient ceiling bars
used with timber joist or lightweight frame floors [1]
Airborne ÷Rw
Airborne ÷Rw + Ctr
Impact ÷Lw
16 dB
14 dB
16 dB
Note:
1) Annex B outlines the laboratory test requirements for resilient ceiling
bars with timber joist or lightweight frame core floors.
3.e
Downlighters (recessed lighting)
Downlighters (or recessed lighting) are often mounted such that they penetrate the
ceiling board lining. The junction between the ceiling board and downlighter
perimeter should be well sealed. It is recommended that downlighters should:
x be at centres of not less than 0.75m;
x have openings no greater than 100 mm diameter or 100x100 mm;
x be installed at no more than one downlighter per 2m2 of total ceiling area in
each room.
Downlighters may be installed at a greater density than 1 per 2m2 if the light fittings
are supported by test evidence undertaken in accordance with Annex B.
Particular attention should be paid to Section 2: Fire of the Technical Handbooks.
16
GENERIC INTERNAL CONSTRUCTIONS
The following internal constructions are provided for internal walls and intermediate
floors.
4.a
Internal walls and intermediate floors
INTERNAL WALLS
DETAIL LINK
1.0
Timber or metal frame with gypsum based board
linings on each side of frame
2.0
Timber or metal frame with gypsum based board
linings on each side of frame and absorbent
material
3.0
Concrete block wall, plaster or gypsum based
board finish on both sides
4.0
Aircrete block wall, plaster or gypsum based board
finish both sides
Wall Type 1 - 4
INTERMEDIATE
FLOORS
Floor Type 1 - 3
DETAIL LINK
1.0
Timber or metal joist, with wood based board and
gypsum based board ceiling and absorbent
material
2.0
Concrete beams with infilling blocks, bonded
screed and ceiling
3.0
Concrete planks
17
4.b
Internal wall details
Type 1
Timber or metal frame with gypsum based board linings
on each side of frame
x Each lining to be 2 layers of
gypsum based board, total
minimum mass per unit area
10 kg/m2 each layer;
x Linings fixed to timber frame
75 x 38 mm at 600 mm
centres with a minimum
distance between linings of
75 mm, or metal ‘C’ type
frame at 600 mm centres
with a minimum distance
between linings of 48 mm;
x All joints staggered and well
sealed.
Type 2
Section
Timber or metal frame with gypsum based board linings
on each side of frame and absorbent material
x Single layer of gypsum based
board of minimum mass per
unit area 10 kg/m2;
x Linings fixed to timber frame
75 x 38 mm at 600 mm
centres with a minimum
distance between linings of
75 mm, or metal ‘C’ type
frame at 600 mm centres with
a minimum distance between
linings of 48 mm;
x An absorbent layer of mineral
wool batts or quilt (minimum
thickness 25 mm and
minimum density 10 kg/m3)
that may be wire reinforced
and suspended in the cavity;
x All joints well sealed.
Type 3
Timber
or
metal
frame
Timber
or
metal
frame
Section
Concrete block wall, plaster or gypsum based board
finish on both sides
x Minimum mass per unit area,
excluding finish 120 kg/m2;
x All joints well sealed;
x Plaster or gypsum based
board on both sides.
Section
18
Type 4
Aircrete block wall, plaster or gypsum based board finish
both sides
x Plaster finish, minimum
mass per unit area, including
finish 90 kg/m2;
x Gypsum based board finish,
mass per unit area, including
finish 75 kg/m2;
x All joints well sealed.
Note 1: this wall type should
only be used with separating
walls included in Example
Constructions where there is no
recommended mass on the
internal masonry walls.
Note 2: this wall type should not
be used as a load-bearing wall
connected to a separating floor
included in Example
Constructions.
19
Section
4.c
Intermediate floor details
Type 1
Concrete slab
x Minimum mass per unit area
180 kg/m2;
x Regulating screed optional;
x Ceiling finish optional.
Section
Type 2
Concrete beams with infilling blocks, bonded screed and
ceiling
x Minimum mass per unit area
of beam and block 220 kg/m2;
x Bonded screed. Sand cement
screeds should have a
minimum thickness of 40 mm.
For proprietary bonded screed
products, screed thickness
should be as recommended
by the manufacturer;
x Ceiling finish - single layer of
gypsum based board,
minimum mass per unit area
10 kg/m2;
x Fix using timber battens or
proprietary resilient channels.
If resilient channels are used,
incorporate an absorbent
layer of mineral wool,
minimum density 10 kg/m2
that fills the ceiling void.
Type 3
Section
Timber or metal joist, with wood-based board and
gypsum based board ceiling and absorbent material
x Floor surface of timber - or
wood-based board, minimum
mass per unit area 15 kg/m2;
x 47 x 200 mm joists at 450 mm
centres;
x Ceiling treatment of two layers
of gypsum based board,
minimum mass per unit area
10 kg/m2 and fixed using any
accepted fixing method;
x An absorbent layer of mineral
wool, minimum thickness 100
mm, minimum density 10
kg/m3 and laid in between the
joists.
20
Timber or
metal joist
Section
Annex A
Explanation of terms
The following terms are provided for clarity, and are for use with the Example
Constructions and Generic Internal Constructions. It is not the intention that any of
these terms relate to proprietary products.
Absorption is the conversion of sound energy into heat, often by the use of a
porous material.
Absorbent material is a material that absorbs sound energy, such as mineral wool.
Airborne sound is sound which is propagated from a noise source through the
medium of air. Examples of these are speech and sound from a television.
Airborne sound transmission is direct transmission of airborne sound through
walls or floors. When sound energy is created in a room, for instance by
conversation, some of the energy is reflected or absorbed by room surfaces but
some may set up vibrations in the walls and floor. Depending on both the amount of
energy and the type of construction, this can result in sound being transmitted to
adjacent parts of the building.
Air path is a void in construction elements, which adversely affects the performance
of sound resisting construction. Examples of air paths include incomplete mortar
joints, porous building materials, gaps around pipes and shrinkage cracks.
Bonded resilient cover (BRC) is a thin resilient floor covering normally of minimum
3 mm thickness which is bonded to the isolated screed surface to reduce impact
sound transmission such as footfall noise.
Cavity stop is a proprietary product or material such as mineral wool (fibre) used to
close the gap in a cavity wall.
Composite resilient batten this is composed of a timber batten with a pre-bonded
resilient material to provide isolation between the flooring surface layers and floor
base.
Cradle/Saddle is an intermediate support system (with a resilient layer base, either
pre-bonded or already integral) using levelling packer pieces to support a timber
batten, isolating it from the floor base.
Decibel (dB) is the unit used for different acoustic quantities to indicate the level with
respect to a reference level.
Density (kg/m3) is the mass per unit volume, expressed in kilograms per cubic
metre (kg/m3). Blockwork is commonly referred to by industry in terms of strength (in
21
Newtons). However, it is the density that has the important role in terms of sound
insulation.
Direct transmission refers to the path of either airborne or impact sound through
elements of construction.
DnT,w is the weighted standardized level difference. A single-number quantity
(weighted) which characterises the airborne sound insulation between two rooms, in
accordance with BS EN ISO 717-1:1997
Flanking element (flanking wall) is any building element that contributes to the
airborne sound or impact transmission between rooms in a building which is not the
direct separating element (i.e. not the separating wall or separating floor).
Flanking strip or edge strip is a resilient strip using foamed polyethylene normally
5 mm thick, which is located at the perimeter of a floor to isolate the floor boards
from the walls and skirtings.
Flanking transmission is airborne or impact transmission between rooms that is
transmitted via flanking elements and/or flanking elements in conjunction with the
main separating elements. An example of a flanking element is the inner leaf of an
external wall that connects to the separating ‘core’ of a wall or floor.
Flexible closer is a flexible cavity stop or cavity barrier which seals the air path in
cavities linking adjoining dwellings.
Floating floor treatment (FFT) is a timber floating floor system which may use
battens, cradles or platform base, all of which use a resilient layer to provide isolation
from the base floor and adjacent wall elements.
Gypsum based board is a dry lining board applied to walls, ceilings and within
floating floor treatments which has gypsum content. It may also have fibre
reinforcement within the board.
Impact sound is sound which is propagated from a noise source through a direct
medium. An example of this is footfall on a floor.
Impact sound transmission is sound which is spread from an impact noise source
in direct contact with a building element.
Isolation is a strategy to limit the number and type of rigid connections between
elements of construction.
L’nT,w is the weighted standardized impact sound pressure level. A single-number
quantity (weighted) to characterise the impact sound insulation of floors, in
accordance with BS EN ISO 717-2: 1997.
Mass is a physical quantity that expresses the amount of matter in a body. Walls
and floors may be described in terms of the surface density (mass per unit area,
kg/m2) of the wall face or the floor surface, which is the sum of the surface densities
22
of each component of the construction. The density of materials is expressed as
mass per unit volume, kg/m3, which can be provided via the core structure and
linings such as in-situ concrete or solid dense block walls.
Mass per unit area (or surface density) is expressed in terms of kilograms per
square metre (kg/m2). This is often used to describe boards, panels, flooring and dry
linings (see gypsum based board).
Resilience can reduce structural vibration transmission and still maintain material
performance and overall dimensions, examples include floating floor treatments such
as resilient battens or cradles, or resilient ceiling bars.
Resilient ceiling bars are generally metal based and vary in thickness from 11 mm
to 30 mm. They are mounted perpendicular to the joist span direction and can
increase both airborne and impact sound insulation. Care should be taken to ensure
that the ceiling board fixings into the resilient bar do not come into contact with the
joists and reduce the potential performance.
Resilient noggin a small section of resilient ceiling bar which is used to assist in
bracing non load bearing partitions.
Rw a single-number quantity (weighted) which characterises the airborne sound
insulation of a building element from measurements undertaken in a laboratory, in
accordance with BS EN ISO 717-1: 1997
Stiffness can improve low frequency sound insulation, for example in floors, by
reducing the potential for deflection or movement of the primary structure, therefore
the correct spacing and depth of joists is important.
23
Annex B
Laboratory test procedures for building products and components
Annex B is aimed at manufacturers of acoustic products and outlines the laboratory
test procedures and methodologies for the acoustic testing of building components
which may be used as part of the Example Constructions.
The weighting terms (as the name suggests) used in this annex applies a focus or
weighting of how the wall or floor is performing for certain types of frequencies and
sounds. Such terms are applied to reflect the location the wall or floor may be
situated within / adjacent to and the type of noise source the wall has to insulate
against.
The building components which may be assessed by laboratory testing are
described in the following sections:
B1
General requirements for the testing of Bonded Resilient Covers
(BRC’s), Floating Floor Treatments (FFT’s) and resilient bars
B2
Determination of the acoustic performance of Bonded Resilient Floor
Coverings (BRC’s) used with concrete core floors
B3
Determination of the acoustic performance of Floating Floor
Treatments (FFT’s) used with concrete core floors
B4
Determination of the acoustic performance of Floating Floor
Treatments (FFT’s) used with timber core floors
B5
Determination of the acoustic performance of resilient bars used with
timber core floors
B6
Determination of the acoustic performance of downlighters and
recessed lighting used with timber core floors
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B1
General requirements for the testing of Bonded Resilient Coverings
(BRC’s), Floating Floor Treatments (FFT’s) and resilient bars
Test facility accreditation
The test facility must have UKAS Accreditation (or European equivalent) for the
measurement of sound insulation in the laboratory for both airborne sound insulation
and impact sound transmission.
Test facility requirements
The test measurement should be undertaken in accordance with:
x BS EN ISO 140-3: 1995 for FFT’s and resilient bars only;
x BS EN ISO 140-6: 1998 for FFT’s and resilient bars only;
x BS EN ISO 140-8: 1998 for BRC’s only.
The performance of each measurement should be rated in accordance with:
x BS EN ISO 717-1: 1997 (for airborne sound), and
x BS EN ISO 717-2: 1997 (for impact sound).
The measurements should be undertaken in a laboratory with suppressed flanking
transmission and in accordance with:
x BS EN ISO 140-1: 1998; and
x BS EN ISO 140-2: 1991.
B2
Determination of the acoustic performance of Bonded Resilient
Coverings (BRC’s) used with concrete core floors
To determine the acoustic performance of BRC’s used with concrete core separating
floors impact measurements should be undertaken in an acoustic test laboratory.
The measurement and performance rating criteria are outlined below.
Test facility accreditation and requirements – in accordance with B1.
Core floor
Testing should be undertaken on a core (or base) floor which consists of an in-situ
concrete slab 140 mm thick.
The tapping machine should not be placed directly onto the resilient floor cover as
this leads to exaggerated performance values which are not representative of real
buildings with hard floor finishes.
The test sample resilient floor cover should be tested with a wood based floor
covering laid over the test sample area. The test sample area and wood based floor
covering should be of sufficient size to permit a tapping machine to be placed on top
of the test materials. The wood based floor covering should be 8 mm (min) to 16 mm
(max) thickness with a nominal density of 600 kg/m3 (+/- 30 kg/m3).
25
The floor test samples should be measured with a uniformly distributed load of 25
kg/m2 with at least one weight per square metre of the flooring area as described in
BS EN ISO 140-8.
Testing required
Impact
Test 1 - Determination of Ln,w for the core (or base) concrete floor.
Test 2 - Determination of Ln,w for the core (or base) concrete floor with the resilient
cover applied to the core floor surface.
Expression of performance
The impact sound transmission performance of the resilient covering should be
expressed as the weighted reduction in impact sound transmission/pressure level
(÷Lw) as a result of the application of the resilient covering to the core floor (÷Lw =
Test 1 – Test 2).
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B3
Determination of the acoustic performance of Floating Floor Treatments
(FFT’s) used with concrete core floors
To determine the acoustic performance of FFT’s used with concrete core separating
floors airborne and impact measurements should be undertaken in an acoustic test
laboratory. The measurement and performance rating criteria are outlined below.
Test facility accreditation and requirements – in accordance with B1.
In addition to B1, the R’max value of the laboratory test facility should be at least 10
dB greater than the sound insulation of the structure under test.
Core floor
The airborne and impact performance for FFT’s can be determined by using an insitu concrete floor in accordance with B2 or the pre-cast concrete core floor below.
CORE (BASE) Concrete floor with FFT’s
Testing should be undertaken on a core (or base) floor which consists of the
following construction:
Screed
10 mm (min) – 25 mm (max) levelling screed min. 80 kg/m2
with bonding agent applied such that it is directly bonded to
the entire floor surface of the slab (planks).
150 mm deep hollow-core precast concrete slab (plank) of
mass per unit area 295-305 kg/m2.
Precast slab (plank)
The hollow segments of the precast slab (plank) should be
located at regular centres and should be distributed over a
minimum of 80% of the slab (plank) width.
The precast concrete hollow-core slab (planks) should be
mounted in the test aperture to cover the entire test aperture
area.
Core floor
construction
The slab (planks) should be tightly abutted and all joints
should be filled with grout including top and bottom joints.
No voids should remain at the floor perimeter junction with
the test aperture border.
No ceiling treatments or layers should be applied.
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The FFT should cover the entire test area of the core floor
surface and should be constructed in accordance with the
manufacturer’s instructions.
Floating Floor
Treatment (FFT)
All FFT’s require a resilient flanking strip to isolate the edge
of the floor board from the perimeter walls.
The manufacturer should use the flanking strip, which they
would normally use on site, in the laboratory measurements.
The flanking strip design and specification should be
consistent with the Example Constructions.
Testing required (FFT)
For the purposes of evaluating the performance of a FFT for concrete core floors
four different measurements are required (two airborne and two impact).
Airborne
Test 1 – Determination of Rw for the core (or base) concrete floor.
Test 2 – Determination of Rw for the core (or base) concrete floor with the FFT
applied to the core floor surface.
Impact
Test 3 – Determination of Ln,w for the core (or base) concrete floor.
Test 4 – Determination of Ln,w for the core (or base) concrete floor with the FFT
applied to the core floor surface.
Expression of performance
The airborne sound insulation performance of the FFT should be expressed as the
improvement in airborne sound insulation (÷Rw ) as a result of the application of the
FFT to the core floor (÷Rw = Test 2 – Test 1)
The impact sound transmission performance of the FFT should be expressed as the
reduction in impact sound transmission (÷Lw) as a result of the application of the FFT
to the core floor (÷Lw = Test 3 – Test 4).
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B4
Determination of the acoustic performance requirements of Floating
Floor treatments (FFT) used with timber core floors
To determine the acoustic performance of floating floor treatments used with timber
joist or lightweight frame separating floors airborne and impact measurements
should be undertaken in an acoustic test laboratory. The following sections outline
the measurement and performance rating criteria.
Test facility and accreditation – in accordance with B1.
In addition to B1, the R’max value of the laboratory test facility should be at least 10
dB greater than the sound insulation of structure under test.
CORE (OR BASE) Timber joist floor with FFT
Testing should be undertaken on a core (or base) floor which consists of the
following construction construction:
Floor decking
15 mm OSB timber decking board (or equivalent timber based
board) with mass per unit area of 10-11 kg/m2
Joists
235 mm x 50 mm solid timber joists at least SC3 grade timber
Insulation
100 mm glass based mineral wool insulation with a density of
10-11 kg/m3
Ceiling
Two layers of 12.5 mm gypsum based board with a mass per unit
area for each layer of 8-8.5 kg/m2
The timber joists should be mounted on joist hangers at 450 mm
centres and the 100 mm (deep) glass based mineral wool
insulation should be placed in the cavities between the joists and
also between cavities formed between the joists and the test
aperture border.
Core floor
construction
The floor decking should be mounted on the timber joists with
screws at 300 mm centres. All junctions between the floor surface
perimeter and test aperture should be sealed with a flexible or
acoustic sealant.
The ceiling layers should be mounted with joints staggered and
the first layer (inner layer) should be fixed to the underside of the
joists with screws, at 300 mm centres within the field of the boards
and at 150 mm centres at the board ends. The second layer (outer
layer) should be fixed with screws, at 230 mm centres within the
field of the boards and at 150 mm centres at the board ends. The
perimeter of the ceiling should be sealed with flexible or acoustic
mastic sealant and all joints and screwheads taped with self
adhesive tape.
29
The FFT should cover the entire test area of the core floor surface
and should be constructed in accordance with the manufacturer’s
instructions.
Floating Floor
Treatment
(FFT)
All FFT’s require a flanking strip to isolate the edge of the floor
board from the perimeter walls.
As such the manufacturer should also use the resilient layer and
flanking strip which they would normally use on site in the
laboratory measurements.
The flanking strip design and specification should be consistent
with the Example Constructions.
Testing required
For the purposes of evaluating the performance of a FFT for timber separating floors
four different measurements are required (two airborne and two impact).
Airborne
Test 1 – Determination of Rw and Rw +Ctr for the core (or base) timber floor.
Test 2 – Determination of Rw and Rw+Ctr for the core (or base) timber floor with the
floating floor treatment applied to the core floor surface.
Impact
Test 3 – Determination of Ln,w for the core (or base) timber floor.
Test 4 – Determination of Ln,w for the core (or base) timber floor with the floating floor
treatment applied to the core floor surface.
Expression of performance
The airborne sound insulation performance of the FFT should be expressed as the
improvement in airborne sound insulation for two categories of performance (÷Rw
and ÷Rw+Ctr) as a result of the application of the FFT to the core floor (÷Rw = Test 2
– Test 1) and (÷Rw+Ctr = Test 2 – Test 1).
The impact sound transmission performance of the FFT should be expressed as the
reduction in impact sound transmission (÷Lw) as a result of the application of the FFT
to the core floor (÷Lw = Test 3 – Test 4).
30
B5
Determination of the acoustic performance of resilient bars used with
timber core floors
To determine the acoustic performance of resilient bars for use within separating
floors airborne and impact measurements should be undertaken in an acoustic test
laboratory. The performance of the resilient bars is calculated from the improvement
in airborne and impact performance by a ceiling connected via resilient bars as
opposed to a direct fix ceiling. The ceiling linings should be identical in both tests.
Test facility and accreditation – in accordance with B1.
Direct fix ceiling versus resilient bar ceiling
Testing should be undertaken on a floor with a direct fix ceiling which consists of the
following construction specification:
Floor Decking
15 mm OSB timber decking board (or equivalent timber based
board) with mass per unit area of 10-11 kg/m2
Joists
235 mm x 50 mm solid timber joists SC3 grade timber
Insulation
100 mm glass based mineral wool insulation with a density of 1011 kg/m3
Ceiling
Two layers of gypsum based board with an overall mass per unit
area of 23-25 kg/m2.
The timber joists should be mounted on joist hangers at 450 mm
centres and the 100 mm (deep) glass based mineral wool
insulation should be placed in the cavities between the joists and
also between cavities formed between the joists and the test
aperture border. The floor decking should be mounted on the
timber joists with screws at 300 mm centres. All junctions
between the floor surface perimeter and test aperture should be
sealed with a flexible or acoustic mastic sealant.
Floor
construction
with direct fix
ceiling
The direct fix ceiling is composed of two layers of gypsum based
board which have an overall mass per unit area of 23-25 kg/m2
and have a minimum overall thickness of 30 mm. The ceiling
layers should be mounted with joints staggered and the first layer
(inner layer) should be fixed to the underside of the joists with
screws, at 300 mm centres within the fields of the boards and
150 mm centres at the board ends, and the second layer (outer
layer) should be fixed with screws, at 230 mm centres within the
fields of the boards and at 150 mm centres at the board ends.
The perimeter of the ceiling should be sealed with flexible or
acoustic mastic sealant and all joints and screwheads taped with
self adhesive tape.
31
Floor
construction
with the ceiling
connected via
resilient bars
The floor construction and components used should be identical
to the Direct Fix test structure except that the ceiling is only
connected to the joists via the resilient bars. The resilient bars
should be directly connected to the joists at 400 mm centres
using metal screws, mounted perpendicular to the joist direction
span and in accordance with the manufacturer’s instructions. The
gypsum based board ceiling layers should be identical in their
material properties to those used for the Direct Fix ceiling.
Testing Required
For the purposes of evaluating the performance of resilient bars for four different
measurements are required (two airborne and two impact measurements). The
following measurements are required:
Airborne
Test 1 – Determination of Rw and Rw+Ctr for the floor with a direct fix ceiling.
Test 2 – Determination of Rw and Rw+Ctr for the floor with a ceiling connected with
resilient bars.
Impact
Test 3 - Determination of Ln,w for the floor with a direct fix ceiling.
Test 4 - Determination of Ln,w for the floor with a ceiling connected with resilient bars.
Expression of performance
The airborne sound insulation performance of resilient bars should be expressed as
the improvement in airborne sound insulation for two categories of performance
32
(Rw and Rw+Ctr) as a result of the application of the resilient bar connected ceiling
as opposed to the direct fix ceiling (Rw = Test 2 – Test 1) and (Rw+Ctr = Test 2 –
Test 1).
The impact sound transmission performance of resilient bars should be expressed
as the reduction in impact sound transmission (Lw) as a result of the application of
the resilient bar connected ceiling as opposed to the direct fix ceiling (Lw = Test 3 –
Test 4).
33
B6
Determination of the acoustic performance of downlighters and
recessed lighting used with timber core floors
This test procedure may also be used where a manufacturer may wish to test closer
spacing or increased density of downlighters (i.e. less than 1 per 2m2).
To determine the influence on the acoustic performance due to the presence of
downlighters for use within timber separating floors airborne and impact
measurements should be undertaken in an acoustic test laboratory. The influence on
the acoustic performance of the timber floor is calculated from airborne and impact
measurements on a timber floor structure with and without downlighters present. The
timber floor structure must be identical in both sets of tests (for airborne and impact)
except for the presence of the downlighters.
Test facility and accreditation – in accordance with B1.
In addition to B1, for downlighters to qualify the difference in performance with
the downlighters present should be no worse than 1 dB for both airborne
measurements and impact measurements.
Core timber floor with and without downlighters
Testing should be undertaken on a floor with the following construction specification:
Floor Decking
15 mm OSB timber decking board (or equivalent timber based
board) with mass per unit area of 10-11 kg/m2
Joists
235 mm x 50 mm solid timber joists SC3 grade timber
Insulation
100 mm glass based mineral wool insulation with a density of
10-11 kg/m3
Two layers of gypsum based board with an overall mass per unit
area of 23-25 kg/m2.
Construction of The timber joists should be mounted on joist hangers at 450 mm
initial
timber centres and the 100 mm (deep) glass based mineral wool
floor
(no insulation should be placed in the cavities between the joists
and also between cavities formed between the joists and the
downlighters)
test aperture border. The floor decking should be mounted on
the timber joists with screws at 300 mm centres. All junctions
between the floor surface perimeter and test aperture should be
sealed with a flexible or acoustic mastic sealant.
Ceiling
The direct fix ceiling is composed of two layers of gypsum based
board which have an overall mass per unit area of 23-25 kg/m2
and have a minimum overall thickness of 30 mm. The ceiling
layers should be mounted with joints staggered and the first
layer (inner layer) should be fixed to the underside of the joists
with screws, at 300 mm centres within the fields of the boards
34
and 150 mm centres at the board ends, and the second layer
(outer layer) should be fixed with screws, at 230 mm centres
within the fields of the boards and at 150 mm centres at the
board ends. The perimeter of the ceiling should be sealed with
flexible or acoustic mastic sealant and all joints and screwheads
taped with self adhesive tape.
Construction of The floor construction and components used should be identical
timber floor with to the Initial Timber Floor test structure except that downlighters
have been installed into the ceiling. The downlighters must be
downlighters
spaced at 1 downlighter per 2m2 of ceiling area and at not less
than 0.75m spacings (e.g. 10m2 of ceiling area equates to 5
downlighters)
Testing required
For the purposes of evaluating the influence on performance due to downlighters for
timber separating floors, four different measurements are required (two airborne and
two impact measurements).
Airborne
Test 1 – Determination of Rw and Rw+Ctr for the initial timber floor.
Test 2 – Determination of Rw and Rw+Ctr for the initial timber floor plus downlighters.
Impact
Test 3 – Determination of Ln,w for the initial timber floor.
Test 4 – Determination of Ln,w for the initial timber floor plus downlighters.
Expression of performance
The influence on airborne sound insulation performance as a result of the installed
downlighters should be expressed as two categories of performance (÷Rw = Test 2 –
Test 1) and (÷Rw+Ctr = Test 2 – Test 1).
The influence on impact sound transmission performance as a result of the installed
downlighters should be expressed as the (÷Lw = Test 3 – Test 4).
35
Note: Downlighters which qualify for the above performance requirements should
also be of suitable integrity. Particular attention should be paid to Section 2: Fire of
the Technical Handbooks.
36