D E S I G N G U I D E
A
COUSTIC
I n s u l a t i o n D e s i g n G u i d e
Introduction 2
Product Range, Applications
& Selection Guides 3 – 13
Bradford Acoustic Solutions
Party & Inter ior Walls
Residential & Commercial 14
External Walls 18
Roof/Ceiling Systems 18
Floor/Ceiling Systems 23
Floors 24
Plumbing 25
Gutters & Downpipes 26
Pipes, Tanks & Vessels 27 Factor ies & Workshops 27
Acoustic Baffles 29
Acoustic Enclosures 30
Vibration Damping 34
Air Conditioning Systems 36
Bradford Acoustic Solutions for Specialty Applications Home Cinema 46 Auditor iums 47 Sports Complexes 48 Canteens/Restaurants 50 Karaoke/Night Clubs 50 Shopping Centres 51 Recording Studios 52 Heavy Plant 53 OEM Application 53
Appendix A The Nature of Sound 54 Sound Transmission 57 Flanking Paths 59 Sound Absorption 59 Reverberation 61 Room Acoustics 64 Industrial Acoustics 67 Speech Privacy 68
Appendix B Floor/Ceiling Systems 69 – 70
Appendix C Product Data 71 Sound Absorption Coefficients 74 Static Insertion Loss/Silencers 77 Air Flow Resistivity 78
Appendix D Terminology 79
CSR Bradford Insulation
Regional Contact Details 80
Contents.
The Bradford Insulation Group forms part of theIntroduction.
Building Materials Division of CSR Limited. CSR Bradford Insulation manufactures and markets an extensive range of insulation products offering outstanding thermal, acoustic and fire protection properties for use in all types of domestic and commercial buildings.
Two mineral fibre insulation types are available; ‘Bradford Glasswool’, which is manufactured by controlled felting of biosoluble glass wool bonded with a thermosetting resin; and ‘Bradford Fibertex™Rockwool’ which is spun from natural rock and bonded with a thermosetting resin. Both are available in sheet or roll form and as moulded pipe insulation.
Bradford Thermofoil™and Thermotuff™are a range of aluminium foil laminates available in various grades.
All CSR Bradford Insulation products are tested to meet stringent quality control standards incorporating quality management systems such as AS3902/ISO9002.
ABOUT THIS GUIDE.
The purpose of this guide is to provide information on the technical benefits obtained with the inclusion of acoustic insulation materials in the construction of all types of buildings as well as noise control of machinery.
The range of Bradford products and their applications is presented along with data and worked examples to illustrate design considerations.
This Acoustic Design Guide also outlines the basic properties of sound, and methods for its control. It does not set out to provide a definitive solution to every conceivable noise problem. Rather, it aims to explain the principles involved, so that these principles can be applied along with common sense, to overcome common acoustic problems. Acoustics is however a complex science, and there will be many instances where the services of specialist acoustic consultants or noise control engineers are indispensable. The reader is cautioned against investing large sums of money in noise control without first seeking advice. This is particularly pertinent where compliance with noise abatement orders is concerned.
TECHNICAL ASSISTANCE.
To assist designers, a free and comprehensive technical service, as well as advice and assistance in specifying and using Bradford products is available from CSR Bradford Insulation offices in your region. Further technical data and product updates are also available on the CSR Building Solutions Website: www.csr.com.au/bradford
Information included in this Design Guide relates to products as manufactured at the date of publication. As the CSR Bradford Insulation policy is one of continual product improvement, technical details as published are subject to change without notice.
The Importance of
Acoustic Insulation.
The minimisation of noise has become a significant environmental issue in the modern world, whether at home, at work or on holidays.
CSR Bradford Insulation manufacturers and distributes an extensive range of insulation products that provide excellent noise control properties, as well as the traditional thermal and fire control benefits.
Although all fibrous insulation products can provide some acoustic benefits, CSR Bradford Insulation has a range of products specifically designed and tested for the acoustic insulation market, including:–
ACOUSTIC INSULATION PRODUCT
Bradford Glasswool Partition Batts
Bradford SoundScreen™ Bradford ACOUSTICON™ Bradford Glasswool R1.5 ACOUSTITUFF™Ductliner Bradford Glasswool R1.5 ULTRAPHON™Ductliner Bradford ACOUSTICLAD™
Bradford Glasswool ACOUSTILAG™
Bradford FIBERTEX™Acoustic Baffle
Bradford Glasswool SUPERTEL™
Bradford Rockwool FIBERTEX™450
APPLICATIONS
Economical insulation for internal wall sound absorption in housing, residential apartments or commercial offices. Various systems are available to meet building codes. Unique rockwool insulation system to reduce room-to-room noise transmission in houses.
Commercial and residential metal roofing insulation specially developed to reduce rain noise.
Air conditioning duct internal lining product offering full enclosure with excellent sound absorption properties. High performance acoustic absorption product for ducting, silencers and other acoustic applications.
Wall absorber combining the superior acoustic properties of Bradford Fibertex™Rockwool with a perforated metal panel system.
Pipe insulation product combining the noise barrier properties of loaded vinyl and the absorption benefits of glasswool. Ideal for noisy plumbing.
Rockwool batt enclosed in white polymer film used for which is designed to be hung from the overhead structure to provide acoustic absorption in a room or workplace. General purpose medium density glasswool acoustic insulation.
General purpose premium rockwool acoustic insulation product.
1
1
1
1
Metal Roof Insulation or
Tiled Roof Sarking
2
2
2
2
Ceiling
Insulation
4
4
4
4
External Wall
Insulation/
Party Wall
5
5
5
5
Plumbing
Insulation
7
7
7
7
Home Cinema Wall, Floor &
Ceiling Insulation.
Acoustic Absorbing Panels
3
3
3
3
Internal Wall
Insulation
6
6
6
6
Acoustic Floor/Ceiling &
Floating Floor Insulation
2
2
2
2
Ceiling Tiled Roof Sarking6
6
6
6
AcousticFloor/Ceilings Floating Floors7
7
7
7
Home Cinema5
5
5
5
Plumbing1
1
1
1
Metal RoofingBradford Insulation Application &
Selection Guide for Homes.
Insulation Application Product Type Product Range/Facings Bradford ACOUSTICON™Blanket Medium, Heavy Duty
or Specialty THERMOFOIL™ Bradford Glasswool ANTICON™Blanket R1.5, R2.0, R2.5 Faced Light,
Medium, Heavy Duty
or Specialty THERMOFOIL™ Bradford FIBERTEX™Rockwool R1.5, R2.0, R2.5 Faced Light,
ANTICON™Blanket Medium, Heavy Duty
or Specialty THERMOFOIL™ Bradford THERMOFOIL™Sarking Medium, Heavy Duty,
ANTIGLARE
Bradford THERMOTUFF™Sarking Medium, Extra Heavy Duty, Safety Bradford Glasswool Gold Ceiling Batts R2.0, R2.5, R3.0, R3.5, R4.0 Bradford FIBERTEX™Rockwool
Ceiling Batts R2.0, R2.5, R3.0
Bradford ACOUSTILAG™ 2.5 - 5.0mm
Loose Fill Bags Bradford Glasswool Partition Batts 50, 75 and 100mm Bradford Rockwool SoundScreen™ 75mm
Bradford Glasswool Gold Wall Batts R1.5, R2.0 Bradford FIBERTEX™Rockwool
Wall Batts R1.5, R2.0
Bradford FIBERTEX™Rockwool
Cavity Wall Granulated Loose Fill Bags
Bradford ACOUSTILAG™Pipe Insulation ACOUSTILAG™20, 23 and 26 Bradford HANDITUBE™Pipe Insulation Stocked by CSR Bradford Insulation Bradford FIBERTEX™Rockwool Ceiling Batts R1.5 - R2.0
Bradford Glasswool Wall/Floor Batts R1.5 - R2.0 Bradford FIBERTEX™Rockwool Wall/Floor Batts R1.5 - R2.0 Bradford Rockwool SoundScreen™ 75mm
Bradford Glasswool QUIETEL™ Specialty installation system
Bradford Glasswool SUPERTEL™ Specialty facings available Bradford FIBERTEX™Rockwool
3
3
3
3
Acoustic Internal Walls4
4
4
4
External Walls7
7
7
7
Home Cinema Wall, Floor &
Ceiling Insulation.
Acoustic Absorbing Panels
Acoustic Insulation for Homes.
1
1
1
1
Tiled Roof Sarking or
Metal Roof Insulation
2
2
2
2
Ceiling
Insulation
4
4
4
4
External Wall
Insulation
5
5
5
5
Plumbing
Insulation
3
3
3
3
Internal Wall
Insulation
6
6
6
6
Acoustic Floor/Ceiling &
Floating Floor Insulation
2
2
2
2
Ceiling Tiled Roof Sarking6
6
6
6
AcousticFloor/Ceilings Floating Floors7
7
7
7
Home Cinema5
5
5
5
Plumbing1
1
1
1
Metal RoofingBradford Insulation Application &
Selection Guide for Homes.
Insulation Application Product Type Product Range/Facings Bradford ACOUSTICON™Blanket Medium, Heavy Duty
or Specialty THERMOFOIL™ Bradford Glasswool ANTICON™Blanket R1.5, R2.0, R2.5 Faced Light,
Medium, Heavy Duty
or Specialty THERMOFOIL™ Bradford FIBERTEX™Rockwool R1.5, R2.0, R2.5 Faced Light,
ANTICON™Blanket Medium, Heavy Duty
or Specialty THERMOFOIL™ Bradford THERMOFOIL™Sarking Medium, Heavy Duty,
ANTIGLARE
Bradford THERMOTUFF™Sarking Medium, Extra Heavy Duty, Safety Bradford Glasswool Gold Ceiling Batts R2.0, R2.5, R3.0, R3.5, R4.0 Bradford FIBERTEX™Rockwool
Ceiling Batts R2.0, R2.5, R3.0
Bradford ACOUSTILAG™ 25mm – 50mm
Bradford Glasswool Partition Batts 50, 75 and 100mm Bradford Rockwool SoundScreen™ 75mm
Bradford Glasswool Gold Wall Batts R1.5, R2.0 Bradford FIBERTEX™Rockwool
Wall Batts R1.5, R2.0
Bradford FIBERTEX™Rockwool
Cavity Wall Granulated Loose Fill Bags
Bradford ACOUSTILAG™Pipe Insulation ACOUSTILAG™20, 23 and 26 ARMAFLEX™Pipe Insulation Stocked by CSR Bradford Insulation Bradford FIBERTEX™Rockwool Ceiling Batts R1.5 - R2.0
Bradford Glasswool Wall/Floor Batts R1.5 - R2.0 Bradford FIBERTEX™Rockwool Wall/Floor Batts R1.5 - R2.0 Bradford Rockwool SoundScreen™ 75mm
Bradford Glasswool QUIETEL™ Specialty installation system
Bradford Glasswool SUPERTEL™ Specialty facings available Bradford FIBERTEX™Rockwool
3
3
3
3
Acoustic Internal Walls4
4
4
4
External WallsAcoustic Insulation for Commercial Buildings
1
1
1
1
Ceiling Insulation
(Suspended Grid Ceilings
& Concrete Roof/Soffit)
2
2
2
2
Internal
Partition Wall
Insulation
3
3
3
3
Acoustic
Absorbing
Panels
4
4
4
4
Plumbing
Insulation
5
5
5
5
Plant Room Wall &
Ceiling Insulation
6
6
6
6
Fan Silencer & Fan
Casing Insulation
7
7
7
7
Air Conditioning
Duct Insulation
Insulation Application Product Type Product Range/Facings Bradford Glasswool ANTICON™ R1.5, R2.0, R2.5 Faced Light, and ACOUSTICON™Blanket Medium, Heavy Duty
or Specialty THERMOFOIL™ Bradford FIBERTEX™Rockwool R1.5, R2.0 Faced Light,
ANTICON™Blanket Medium, Heavy Duty or
Specialty THERMOFOIL™ Bradford Glasswool SUPERTEL™ 25 – 75mm
THERMOFOIL™Facing Bradford FIBERTEX™350 Rockwool 50 - 100mm
THERMOFOIL™ Facing
Bradford Glasswool Ceiling Panel Overlays Factory Applied Acoustic Facings Bradford FIBERTEX™Rockwool
Ceiling Panel Overlays Factory Applied Acoustic Facings Bradford Glasswool Building Blanket R1.2, R1.5, R1.8, R2.0, R2.5 Bradford FIBERTEX™Rockwool
Building Blanket 50, 75mm, R1.5, R2.0
Bradford Glasswool Partition Batts 50, 75, 100mm Bradford FIBERTEX™Rockwool Partition Batts 45, 70mm
Bradford Glasswool ULTRATEL™Board 25-100mm, Factory Applied Facings
Bradford FIBERTEX™450 Rockwool 25-100mm,
Factory Applied Facings Bradford ACOUSTILAG™Pipe Insulation ACOUSTILAG™20, 23 and 26 ARMAFLEX™Pipe Insulation Stocked by CSR Bradford Insulation Bradford Rockwool/Glasswool ACOUSTICLAD™
Bradford Glasswool FLEXITEL™, Perforated 750P
SUPERTEL™, ULTRATEL™ THERMOFOIL™
Bradford FIBERTEX™350 Rockwool Perforated 750P THERMOFOIL™ Bradford Glasswool FLEXITEL™ Perforated 750P Bradford Glasswool SUPERTEL™ THERMOFOIL™ Bradford Glasswool QUIETEL™ ACOUSTITUFF™ Bradford FIBERTEX™Rockwool DUCTLINER ULTRAPHON™ Bradford Glasswool SUPERTEL™ BMF, ULTRAPHON™ Bradford Glasswool ULTRATEL™ 25 – 100mm
Bradford Glasswool QUIETEL™ (Quietel 13mm - 50mm) Bradford FIBERTEX™Rockwool DUCTLINER
Bradford FIBERTEX™450 Rockwool
Bradford Glasswool SUPERTEL™ Perforated 750P THERMOFOIL™ Bradford Glasswool DUCTLINER ULTRAPHON™,
Bradford Glasswool ULTRATEL™ ACOUSTITUFF™facings Bradford FIBERTEX™Rockwool DUCTLINER 25 – 100mm, R1.5 & R0.9 Bradford Glasswool MULTITEL™ R1.5 & R0.9
Bradford Glasswool FLEXITEL™ 25 – 100mm Bradford Glasswool THERMOGOLD™DUCTWRAP
Bradford FIBERTEX™Rockwool DUCTWRAP
Bradford Glasswool R1.0 SPECITEL™ R1.0. R1.5
Bradford FABRIFLEX™Flexible Ducting Available ex-Singapore Bradford ACOUSTIFLEX™Flexible Ducting Available ex-Singapore
Bradford Insulation Application & Selection
Guide for Commercial Buildings.
1
1
1
1
Concrete Roof/Soffit Exposed Grid Ceiling Concealed Grid Ceilings2
2
2
2
Acoustic InternalPartitions7
7
7
7
Rigid Ducting Internal Lining4
4
4
4
Plumbing Insulation Rigid Ducting External Wrap Flexible Duct5
5
5
5
Plant RoomWall & Ceiling Insulation6
6
6
6
Fan Casings Fan Silencers3
3
3
3
Acoustic Absorbing PanelsAcoustic Insulation for Theatre, Sports
& Multi-Purpose Buildings
2
2
2
2
Sports Centre
• Roof/Ceiling Insulation
• Floor Insulation
• Acoustic Absorbing
Panels
3
3
3
3
Canteen
• Wall Insulation
• Ceiling Insulation
• Acoustic Absorbing Panels
• Metal Deck Rain Noise Insulation
1
1
1
1
Auditorium/Theatre/Cinema
• Roof/Ceiling Insulation
• Wall Insulation
• Acoustic Absorbing
Panels
4
4
4
4
Air Conditioning
System Insulation
Insulation Application Product Type Walls
Bradford Glasswool Partition Batts Bradford Rockwool Partition Batts Acoustic Absorbers
Bradford Glasswool FLEXITEL™, SUPERTEL™ ULTRATEL™with BMF (Black Matt Facing Tissue), ULTRAPHON™or other specialty facing.
Bradford FIBERTEX™Rockwool
Bradford ACOUSTICLAD Wall/Ceiling Absorber Roof/Ceiling
Bradford Glasswool ACOUSTICON™ Bradford Glasswool Ceiling Batts Bradford Rockwool Ceiling Batts Acoustic Absorbers
Bradford ACOUSTICLAD™Wall/Ceiling Absorber Bradford FIBERTEX™Rockwool
Bradford Glasswool FLEXITEL™, SUPERTEL™ ULTRATEL™with BMF (Black Matt Facing Tissue), ULTRAPHON™or other specialty facing.
Roof/Ceiling
Bradford Glasswool ACOUSTICON™ Bradford Glasswool Ceiling Batts Bradford Rockwool Ceiling Batts Acoustic Absorbers
Bradford FIBERTEX™Rockwool
Bradford Glasswool FLEXITEL™, SUPERTEL™ ULTRATEL™with BMF (Black Matt Facing Tissue), ULTRAPHON™or other specialty facing.
Bradford ACOUSTICLAD Wall/Ceiling Absorber Walls
Bradford Glasswool Partition Batts Bradford Rockwool Partition Batts Roof/Ceiling
Bradford Glasswool ACOUSTICON™ Bradford Glasswool Ceiling Batts Bradford Rockwool Ceiling Batts
Refer to CSR Bradford Insulation Air Conditioning Design Guide and Product Guide.
2
2
2
2
Sports Buildings • Swimming • Basketball • Gymnasium3
3
3
3
Canteen Facility1
1
1
1
Theatre, Cinema & Auditorium4
4
4
4
Air Conditioning SystemsBradford Insulation Application & Selection Guide
for Theatre, Sports & Multi-Purpose Buildings.
Acoustic Insulation for
Industrial Applications.
6
6
6
6
Ceiling
Insulation
1
1
1
1
Acoustic Baffles
(suspended)
8
8
8
8
Acoustic Wall
Absorbers
7
7
7
7
Metal Deck
Roof Insulation
4
4
4
4
Acoustic
Absorbing
Screens
5
5
5
5
Acoustic Internal
Wall Insulation
3
3
3
3
Bradford Insulation
for OEM Applications
2
2
2
2
Acoustic
Enclosures for
Plant & Machinery
3
3
3
3
OEM Applications2
2
2
2
Acoustic Enclosures for Plant & Machinery4
4
4
4
Acoustic Absorbing Screens7
7
7
7
Metal Deck Roofs8
8
8
8
Acoustic Wall Absorbers6
6
6
6
Ceilings1
1
1
1
Acoustic Baffles5
5
5
5
Acoustic Internal WallsBradford Acoustic Insulation for
Industrial Applications.
Insulation Application Product Type Product Range/Facings
Bradford FIBERTEX™Acoustic Baffle Fully enclosed in white polymer film ready to hang.
Bradford FIBERTEX™Rockwool 25 – 100mm
Bradford Glasswool FLEXITEL™ Density 24 – 120kg/m3 Bradford Glasswool SUPERTEL™
Bradford Glasswool ULTRATEL™
Bradford Glasswool Appliance Grade Cut to size with specialty facings Bradford Rockwool Appliance Grade available
Bradford Glasswool QUIETEL™
Bradford Glasswool SUPERTEL™ 25 – 100mm Bradford FIBERTEX™Rockwool
Bradford Glasswool Partition Batts To fit studs Bradford FIBERTEX™Rockwool Partition Batts
Bradford Glasswool Ceiling Batts 50 – 150mm Bradford Rockwool Ceiling Batts
Bradford Glasswool ACOUSTICON™ 75mm Bradford Rockwool ACOUSTICON™
Bradford ACOUSTICLAD™ 25 – 100mm
Interior Walls.
RESIDENTIAL PARTY & INTERNAL WALLS.
The Building Code of Australia (BCA) Sections F5 sets out Sound Transmission Class (STC) requirements for sound insulation of floors, walls, between units, walls between bathrooms, laundries, kitchens, between habitable and non-habitable rooms in multi-tenancy buildings. In late 1999, the BCA changed its acoustic rating from STC to Sound Reduction Index (Rw). This Acoustic Design
Guide uses the STC rating units as Australasia and Asia are familiar with STC and it is very similar to Rw. An increase
of either one STC unit or one Rw unit approximately
equals a reduction of one decibel in noise level.
Table 1 below shows common STC values of walls used in buildings. The expected audibility for a given STC level is also shown, based on guidelines for ambient sound levels
TABLE 1. STC AND AUDIBILITY THROUGH WALLS AND FLOORS.
STC Value Audibility
30 - 35 Speech audible
40 Loud speech, still heard
45 Loud speech, just heard
50 – 55 Speech cannot be heard The BCA Part F5.4 Sound Insulation Of Walls Between Units currently states a wall must have an STC not less than 45. It has been proposed to increase this to STC 55 in the future as STC 45 does not provide enough acoustic privacy. STC’s ≥50 are standard in Europe and USA.
Generally internal walls for residential applications in Australia use either rendered brick or lightweight double leaf walls using plasterboard and/or fibre cement construction on timber studs.
To improve or increase the sound transmission loss (STL) hence the STC of these walls, the following is
required:-EXTRA MASS.
Sound Transmission Loss (STL) depends heavily on the surface density of a building element (mass per square metre of surface). For every doubling of surface density, the sound transmission loss increases by about 5dB.
The addition of denser wall sheeting products such as CSR Gyprock®Fyrchek™or Soundchek™ plasterboard or CSR Fibre Cement together with Gyprock’ Resilient Mounts and furring channels can reduce noise levels.
DOUBLE-LEAF WALLS.
Higher transmission losses than those expected by the Mass Law can be obtained by using double-leaf walls with an air cavity.
Fur ther increases in sound transmission loss, particularly at low frequencies can be achieved by using wider air cavities.
When a double leaf wall is uninsulated, the air in the cavity can act as a spring, efficiently transmitting sound energy from one side of the wall to the other.
Significant improvement in STC is obtained by using Bradford Rockwool or Glasswool batts in the cavity.
Acoustic tests of walls around the world have shown the use of glasswool batts or rockwool batts inside cavity walls reduces resonances between the two sheets and can significantly improve the acoustic performance by up to 10 STC. Generally the thicker and/or denser the insulation in the cavity, the higher the STC rating resulting in less noise transmitted to the other side of the wall. The actual improvement in STC depends on the type of wall construction. Insulation in the cavity will also lessen the effect of the ‘coincidence dip’ in double leaf walls.
FLANKING NOISE.
It should be noted that actual installations, as compared to acoustic laboratories, exhibit flanking noise through doors, windows, ventilation ducting, air gaps at ceiling, wall and floor inter sections. In addition, poor workmanship may degrade the acoustic performance of partitions. For these reasons, a building element constructed in the field will usually achieve a lower STC ratings than when tested in the laboratory.
Maximum acoustic performance can be achieved by eliminating penetrations in walls, caulking gaps, and staggering electrical outlet or other necessary penetrations through the wall. Wall cavities should be completely filled with insulation and tightly fitted around pipes, conduits and other outlets.
LOW FREQUENCY NOISE.
Low frequency noise from sources such as fans, aircraft, road and rail traffic, and bass from amplified music can penetrate walls easier than high frequency noise. Therefore higher sound transmission loss (ie. higher STC) walls are required to ensure satisfactory acoustic performance. As a general rule, add at least 5 STC points to the acoustic requirement of the walls when low frequency noise is present.
STC data for some typical partition walls is given in Table 2. Further STC data for internal cavity walls is available the CSR Bradford brochure ‘Noise Reductions For Internal Partitions or the CSR Gyprock Fire & Acoustic Design Guide, ‘The Red Book’.
TABLE 2. STC DATA FOR TYPICAL TIMBER FRAME PARTITION SYSTEMS.
Description STC (Rw) STC (Rw) STC (Rw)
Bradford Bradford
No Glasswool Rockwool
Insulation Wall Batts Wall Batts
STC 30 - 42
• 1 layer 10mm CSR Gyprock Plasterboard CD™ • 70/75mm Timber Studs
• 1 layer 10mm CSR Gyprock Plasterboard CD™
STC 40 - 50
• 2 layers 13mm CSR Gyprock Fyrchek™plasterboard • 70/75mm Timber Studs
• 1 layer 13mm CSR Gyprock Fyrchek™plasterboard
STC 50 - 60
• 2 layers 16mm CSR Gyprock Fyrchek™plasterboard • 90 x 35mm Staggered Timber Studs
• 2 layers 16mm CSR Gyprock Fyrchek™plasterboard
33 38 39 (75mm Batts) (45mm Batts) Test CSR 37/67 42 SoundScreen™ 43 47 48 (50mm Batts) (45mm Batts) 51 58 59 (50mm Batts) (45mm Batts)
* Refer to the CSR Bradford Noise Reduction of Internal Partitions brochure or the CSR Gyprock®Fire & Acoustic Design Guide (‘The Red Book’) which show a wide range of internal partitions and their STC ratings.
Internal plasterboard or fibre cement walls using steel stud systems are widely used in commercial construction and offer a wide range of sound transmission loss performance.
The methods stated previously for improving acoustic performance of Residential Internal Walls also apply to the Commercial Internal Partitions.
Thinner gauge steel studs, with greater stud spacing and minimum fixing of sheets to studs also results in a wall which is able to flex more easily generally resulting in slightly higher acoustic performance.
If higher STC performance is required, there are a number of steps that can be incorporated at the time of construction to improve acoustic performance, as detailed in Table 3.
TABLE 3. INSULATION FOR NOISE REVERBERATION CONTROL.
Addition STC Improvement Comments
Fit insulation into studs Up to 10 STC points Thicker and/or denser insulation such as Rockwool is beneficial. Light gauge or deeper steel studs give higher STC performance.
Use Gyprock®Fyrchek Up to 3 STC points Use of 13mm or 16mm CSR plasterboard if installed both sides Gyprock®Fyrchek™improves performance due to extra mass. Gyprock®Resilient Channel 6 – 8 STC points Resilient Channel isolate the
one side Gyprock®Plasterboard from the stud.
Bradford Quietel one side and 4 STC points Quietel board acts as a sound
insulation to stud isolator between the Gyprock®
Plasterboard and the Stud.
Staggered and double studs Up to 10 STC points Provide sound breaks between solid studs and Gyprock®. Recommended where impact isolation is also required. Gyprock®Resilient Mounts and Up to 10 STC points Used where high level reduction of
Furring Channel airborne and impact noise is required.
COMMERCIAL INTERNAL PARTITIONS.
* Refer to the CSR Bradford Insulation Noise Reduction of Internal Partitions brochure or CSR Gyprock® Fire & Acoustic Design Guide (‘The Red Book’) which show a wide range of internal partitions and their STC ratings.
Description STC (Rw) STC (Rw) STC (Rw)
Bradford Bradford
No Glasswool Rockwool
Insulation Partition Batts Partition Batts
STC 30 - 40
• 1 layer 13mm Gyprock Plasterboard CD™ • 64mm Steel Studs
• 1 layer 13mm Gyprock Plasterboard CD™
STC 40 - 50
• 1 layer 16mm Gyprock Fyrchek™ • 64mm Steel Studs
• 1 layer 16mm Gyprock Fyrchek™
STC 50 - 60
• 1 layer 13mm Gyprock Fyrchek™plasterboard • 64 x 0.75mm BMT Separated Steel Studs • 1 layer 13mm Gyprock Fyrchek™plasterboard
STC 55 - 60
• 1 layer 16mm Gyprock Fyrchek™plasterboard • 64 x 0.75 BMT Separated Steel Studs
• 1 layer 16mm Gyprock Fyrchek™plasterboard
STC 60 - 70
• 2 layers 16mm Gyprock Fyrchek™plasterboard • 92 x 0.75mm BMT Separated Steel Studs • 2 layers 16mm Gyprock Fyrchek™plasterboard
TABLE 4. STC RATINGS OF SOME COMMERCIAL INTERNAL PARTITIONS*.
A sample of the STC ratings for commercial internal partitions using steel studs taken from the Tables in the CSR Bradford Insulation ‘Noise Reductions for Internal Partitions’ brochure, together with results from recent testing.
35 40 41 (50mm Batts) (45mm Batts) Test HAS 085 39 44 45 (50mm Batts) (45mm Batts) 45 57 58 (75mm (75mm Wall Batts) SoundScreen™)
45 55 60
(80mm Batts) (75mm SoundScreen™)
55 63 64
(75mm Batts) (70mm Batts)
CSR Bradford Insulation has available a sophisticated ‘Acoustic Predictor’ computer program, developed by CSR Gyprock®, which can predict the STC rating of many different internal partitions, in addition to those shown above and in the brochure.
Note: For walls which require high sound transmission
loss STC greater than 50, such as those used between recording studios or cinemas, flanking paths should be considered, as they can derate the acoustic performance of the partition. For cinema walls requiring a very high STC rating, contact CSR Bradford Insulation regarding the CSR Gyprock®Cinema Wall System, or other CSR systems.
External Walls.
External walls of residential buildings usually consist of • brick veneer construction, or lightweight concrete
construction,
• a cladding material, usually timber or fibre cement or • occasionally double brick.
For better acoustic performance, use building materials with more mass. Clay bricks provide high surface density (or mass per square metre) to enable high transmission loss.
The use of CSR Gyprock®Soundchek™or Fyrchek™ plasterboard is recommended for interior walls. For even higher wall STC, the use of CSR Gyprock® Resilient Mounts and Furring Channels is recommended.
For brick veneer walls add the thickest possible rockwool or glasswool batts inside wall cavities during construction of the building.
Granulated rockwool can be retro-fitted into existing walls of a building using a special machine which blows granulated rockwool under pressure into the wall cavities. Wall sheeting usually has solid connections (ie screw or nail fixed) to the timber or steel studs and transmits noise through these solid connections. CSR Gyprock® Resilient Mounts can reduce both noise and vibration transmission.
To improve STC performance of single timber studs, consider the use of Rondo resilient channels or CSR Gyprock®resilient mounts with furring channels, which can improve STC (or Rw) by 6 to 8.
Buildings with double brick walls should use vibration isolated wall ties to reduce the amount of noise and vibration transmitted from one wall to the other.
Note that building elements of low acoustic performance will derate the improvements made to other building elements ie. walls and ceilings. For example, lightweight windows and doors can reduce the overall STC rating of the wall.
Products.
Bradford Glasswool Wall Batts
Bradford Rockwool Wall and Ceiling Batts
Roof/Ceiling Systems.
Roof/ceiling systems generally consist of either steel roofing or tile roofing. These roofing systems usually provide average to poor acoustic performance and can be an acoustically weak link in a building facade. It should be noted that consideration should be given to other weak links in the building extensions such as windows and doors.
Low frequency noise generated by aircraft, road and rail traffic can easily penetrate commonly used building materials including the roofing.
Tile roofs are generally used in domestic applications. It is recommended that Bradford Rockwool or Glasswool Ceiling Batts be used in the roof cavity to improve both acoustic and thermal resistance. Note the higher the thermal resistance or R-value, the thicker the batt, and the better the acoustic absorption.
The following points indicate methods to improve the acoustic performance of a typical tiled roof system. Tips on how to further improve the STC rating are provided in (brackets)
• Rockwool or glasswool insulation batts on top of the ceiling, (the thicker the insulation or the higher the R-rating, the better the acoustic absorption)
• Using a heavy THERMOFOIL™ sarking as a condensation barrier under the roof tiles, the heavier the better the noise reduction.
• Adding Bradford SOUNDLAGG™loaded vinyl over the ceiling joists, (the heavier the better).
• Thicker and/or heavier plasterboard for the ceiling, (use fire rated plasterboard and multiple layers). Care should be taken to minimise all gaps in the roof ceiling to maximise the acoustic performance.
Gyprock® Plasterboard Bradford Thermofoil or Thermotuff Breather Bradford Insulation Wall Batts External Cladding Timber Frame FIG 1.
Figure 2 shows how to improve the acoustic performance of a typical tiled roof system.
Note that the gaps inherent in tile roof construction allow noise to enter the roof cavity. Hence the use of
rockwool or glasswool insulation will maximise noise absorption in the roof space, minimising the amount of noise entering the room/s below.
Steel roofing is used in both commercial and residential roofing systems in Australia, New Zealand and Asia.
Metal deck roofing systems require a layer of thermal insulation faced with a suitable vapour barrier to be
installed directly underneath the metal decking to guard against condensation.
Figure 3 shows the improvement in STC of a typical domestic roof with the addition of Bradford insulation in the roof/ceiling system.
Bradford Glasswool or Rockwool Ceiling Batts (as indicated) Bradford Thermofoil 733
Sarking over rafters
Gyprock 10mm Supa-Ceil Plasterboard Ceiling Ceiling Joist Monier Concrete Roof Tiles Bradford Soundlagg (6kg/m2) over joists
FIG 2. IMPROVING ACOUSTIC PERFORMANCE OF TILED ROOF SYSTEMS.
SYSTEM
Monier concrete tile roof with one layer of Gyprock Supa-Ceil™ plasterboard fixed to ceiling joists spaced at 600mm centres.
Add Bradford R2.5 Glasswool Batts between joists.
Replace Bradford R2.5 Glasswool Batts with Bradford R3.0 FIBERTEX™ Rockwool Building Batts between joists, and install Bradford
THERMOFOIL™733 over rafters. Add Bradford SOUNDLAGG™ (6kg/m2) over ceiling joists.
STC/Rw 33 41 45 50 Bradford Fibertex Rockwool Batts or (Bradford G lasswool Ceiling Insulation in New Zealand) Metal Roofing Gyprock 10mm Supa-Ceil Plasterboard Ceiling Ceiling Joist Bradford Acousticon Foil Faced Blanket
FIG 3. IMPROVING ACOUSTIC PERFORMANCE OF STEEL ROOF SYSTEMS.
SYSTEM
Metal roofing with 1 x 10mm Gyprock Supa-Ceil™plasterboard fixed to ceiling joists spaced at 600mm centres.
Add Bradford ACOUSTICON™foil faced building blanket over rafters under metal roofing.
Add Bradford R2.5 FIBERTEX™ Rockwool Building Batts between joists. Replace Supa-Ceil plasterboard with 2 layers x 13mm Gyprock Plasterboard CD fixed to metal furring channels (at 600mm max. cts) attached by Gyprock Resilient Mounts
Metal roofing with one layer plasterboard fixed to ceiling joists spaced at 600mm cts. plus Bradford Ceiling Insulation between joist. (New Zealand only).
STC/Rw 34 41 45 52 39 – 41
TILED ROOF SYSTEMS.
The STC of a roof system (commercial, industrial or domestic) can also be improved with the addition of heavier building materials such as:
• addition of insulation between the roof sheeting and Bradford batts above the ceiling,
• thicker steel roof sheeting,
• using heavier, fire rated plasterboard or multiple layers for the ceiling,
• installing a layer of Bradford SOUNDLAGG™beneath (4 kg/m2or heavier).
RAIN NOISE REDUCTION WITH METAL DECK ROOFING
A common problem of steel roofing is that of rain noise, particularly in tropical climates with high levels of rainfall. Rain falling on metal deck roofing can cause unacceptably high noise levels in the space below the roof. The impact causes the stiff lightweight roof sheeting to vibrate, thus emitting noise. Damping the vibration of the roof sheeting reduces the emitted noise.
Rockwool and glasswool blanket products have exceptional noise absorbing properties providing effective damping of the steel roof sheeting.
CSR Bradford Insulation in conjunction with CSR Gyprock®have constructed a rain noise testing facility to simulate rain noise using conventional 0.42mm thick BHP Trimdek Hi-Ten metal roof cladding. The rain noise test rig has four nozzles spraying water at high pressure simulate high intensity rainfall. Continuous noise levels of 89dB(A) were created inside the test rig, this noise level was used for controlled testing purposes.
Figure 4 shows the rain noise insertion losses achieved by using Bradford Insulation Blankets faced with Thermofoil 729. All tests used 0.42mm BMT BHP Trimdek Hi-Ten steel roofing.
Bradford ACOUSTICON™ Glasswool Roofing Blanket is f aced with THERMOFOIL™. ACOUSTICON™ has been specially developed to provide cost effective rain noise reduction of 18dB(A) inser tion loss under metal deck roofing. ACOUSTICON™ has BHP approval for use under all types of Lysaght steel roofing profiles, including Klip-Lok. For more infor mation refer to the Bradford ACOUSTICON™ ‘A Quiet Step Forward’ brochure, available from your nearest Bradford office.
For optimum rain noise reduction under steel roofing in commercial, industrial and residential applications, install 75mm Bradford ACOUSTICON™.
For residential applications, ensure the correct rating of thermal insulation is achieved for roof insulation in your region. At least R2.0 Bradford Rockwool or Glasswool Ceiling Batts should be installed between ceiling joists in conjunction with a Bradford ACOUSTICON™.
CSR Bradford Insulation and CSR Gyprock® have conducted many tests using various foil faced roofing insulation blankets, ceiling tiles and fixed plasterboard ceilings. The results of these are shown in Table 5.
In tropical climates, roofing insulation is generally installed foil face up, ie. the foil in direct contact with the metal deck roof sheeting. This reduces the insertion loss of the roofing blanket by 2dB. The use of Bradford Rockwool™ACOUSTICON™is therefore recommended. Rain noise tests were conducted using the same thickness/density glasswool blanket and varying the surface density of foil. It was found that the mass of the foil has no effect on the rain noise insertion loss achieved by the insulation.
ACOUSTICON™and ANTICON™roofing blankets should be installed so the blanket is firmly in contact with the steel roofing as shown in Figure 5. This has the added benefit of damping the metal roof sheeting and reducing rain noise.
10 11 12 13 14 15 16 17 18 19 20 Insertion Loss db(A)
50mm Glasswool blanket 50mm Bradford Rockwool
75mm Bradford ACOUSTICON Optimum
50mm Polyester Blanket
FIG 4
RAIN NOISE REDUCTION INSERTION LOSSES – FOIL FACED ROOFING BLANKETS.
Bradford Acousticon Support Mesh (when specified) Bradford Thermofoil Vapour Barrier Metal Deck Roofing
Purlin
FIG 5.
TABLE 5. NOISE REDUCTION CEILING SYSTEMS.
Ceiling System Description Rain Noise
Reduction Level dB(A) • Bradford ANTICON™R1.5 Blanket hard under metal deck roof
• Bradford ACOUSTICON™hard under metal deck roof • Bradford FIBERTEX™Rockwool ACOUSTICON™
hard under metal deck roof
• Rondo Suspended Concealed Grid Ceiling System. • 1 layer x 13mm Gyprock Plasterboard CD.
• Bradford ANTICON™R1.5 Blanket hard under metal deck roof • Rondo Suspended Exposed Grid Ceiling System.
• CSR Gyprock Ecophon™20mm Lay-in Ceiling Tiles. • Bradford ANTICON™R1.5 Blanket hard under the roof. • RONDO Suspended Exposed Grid Ceiling System. • CSR Gyprock CELOTEX™16mm Lay-in Ceiling Tiles. • Bradford ANTICON™R1.5 Blanket hard under the roof. • RONDO Suspended Exposed Grid Ceiling System. • Gyprock 13mm Lay-in Ceiling Tiles.
• Bradford ANTICON™R1.5 Blanket hard under the roof. • RONDO Suspended Concealed Grid Ceiling System. • 1 layer x 13mm Gyprock Plasterboard CD.
• Bradford ANTICON™R1.5 Blanket hard under the roof. • RONDO Suspended Concealed Grid Ceiling System. • 1 layer x 13mm Gyprock Plasterboard CD.
• Bradford R1.5 GOLD BATTS or R1.5 Glasswool Building Blanket laid over the ceiling. • Bradford ANTICON™R1.5 Blanket hard under the roof.
• RONDO Resiliently Mounted Suspended Concealed Grid Ceiling System. • 2 layers x 13mm Gyprock Fyrchek™Plasterboard.
• Bradford R1.5 GOLD BATTS or R1.5 Glasswool Building Blanket laid over the ceiling.
15 18 19 22 25 30 34 37 45 51
Products for Metal Deck Roofing Systems.
• Bradford Glasswool Acousticon™75mm. (R1.8) • Bradford 50mm Commercial Grade Anticon™. • Bradford Glasswool R1.5 Anticon™55mm. • Bradford Glasswool R2.0 Anticon™75mm. • Bradford Glasswool R2.5 Anticon™95mm. • Bradford 50mm Rockwool ACOUSTICON™.
CEILINGS.
Fixed plasterboard ceilings generally provide better sound transmission loss (ie. higher STC) than lightweight suspended ceiling tiles and even plasterboard ceiling tiles. This is because the fixed plasterboard ceiling is better sealed and has less gaps. Multiple layers of plasterboard with resilient mounting and rockwool or glasswool batts in the cavity can provide high STC rating. The larger the
Refer to the CSR Gyprock®Fire & Acoustic Design Guide (‘The Red Book’) for additional information on rain noise reduction ceiling systems. See comments regarding: Tropical climate applications in Bradford ACOUSTICON™brochure.
ceiling cavity, the better the low frequency noise reduction.
The ceiling can be an important area of a room to place sound absorption particularly, when the remainder of the rooms contains hard reflective surfaces. Rooms having no sound absorbent surfaces typically have high reverberation times. This results in poor acoustics, particularly if communication is required within the room.
Generally commonly used plasterboard ceilings, whether fixed or lay in ceiling tiles are not very effective at absorbing sound.
Typically, sound absorptive ceilings generally consist of:
• ceiling tiles made of high density rockwool or glasswool (typically NRC 0.70 – 0.95),
• perforated plasterboard or perforated metal pan ceilings with Bradford Rockwool or Glasswool insulation (faced with a black tissue) above (good sound absorption NRC 0.60 – 0.90),
• Mineral fibre ceiling tiles (average sound absorption NRC 0.50 – 0.60).
Note that better low frequency acoustic absorption results when ceiling tiles are installed with an air cavity. The larger the air cavity, the better the low frequency acoustic absorption.
In many commercial office buildings, noises such as conversations, telephones ringing etc can be heard from one office to another (also known as ‘Crosstalk’). This can cause disruption, annoyance, and decreased productivity. Crosstalk usually occurs from sound flanking via the ceiling.
In commercial office buildings, the walls are built up to the underside of the lightweight suspended ceilings (usually a metal grid), not to the concrete slab above. The lightweight ceilings tiles used generally have a low STC rating. The void above wall and ceiling allows sound to ‘flank’ from one room to the next via the acoustically weak ceiling tiles. Ideally, the wall should be built up to the underside of the floor above without gaps for sound to pass from one side to the other.
To reduce the amount of sound flanking when a wall does not continue to the underside of the floor above, it is recommended that Bradford Rockwool or Glasswool Ceiling Batts be installed between the wall/ceiling and the underside of the floor above. The more compressed the insulation is when installed in this way, the better the acoustic performance. refer to Figure 6.
Alternatively, to reduce flanking via the ceiling, install Bradford Acoustilag™from the underside of the concrete slab to the ceiling below as shown in Figures 7 and 8.
Products - Ceilings.
• Bradford Rockwool Ceiling Batts R1.5, R2.0, R2.5, R3.0.
• Bradford Glasswool Ceiling Batts R2.0, R2.5, R3.0, R3.5, R4.0.
• Bradford Glasswool Ceiling Panel Overlays (optional Black Matt Facing, or ULTRAPHON™)
• Bradford Glasswool Absorption Blanket (optional Black Matt Facing or ULTRAPHON™
• Bradford Fibertex™Rockwool (optional Black Matt Facing or ULTRAPHON™)
Ducting Ducting
Poor sound privacy caused by sound flanking through lightweight suspended ceiling
FIG 6. IMPROVING SOUND TRANSMISSION CONTROL THROUGH CEILING AREA WITH
BRADFORD INSULATION.
Ducting Ducting Improved privacy with Bradford Rockwool or Glasswool Ceiling Batts in ceiling space over wall
Bradford Rockwool or Glasswool Partition Batts Bradford Rockwool or Glasswool
Ceiling Batts compressed between ceiling and slab above
Cabling Ducting
NOTE: Care must be taken when passing cables through insulation material due to possible overheating. Consult your electrician for more details.
Floor/Ceiling Noise
Control Systems.
Multi-storey buildings with hard flooring such as timber, parquetry or tiles etc., can efficiently transmit both airborne and impact noise (structure borne vibration) to the rooms below if appropriate techniques are not incorporated at the time of construction. Installing carpet and underlay on the floor can significantly reduce the impact noise to the room below.
Installing R2.0 or greater, Bradford Rockwool or Glasswool batts between the floor joists will reduce airborne noise by approximately STC 4 – 6.
At the time of printing this guide, The Building Code Of Australia (BCA) ‘Sound Insulation of Floors Between Units’ stated ‘a floor separating sole occupancy units must have an Rwof not less than 45’. (Note: Rw
45 approximately equals STC 45). Floors must also provide insulation against impact generated sound.
It should be noted that STC 45 is not always adequate in reducing airborne sound through floors and walls. For better acoustic privacy, it is preferable to use a higher rating of say Rw50 or preferably Rw55.
RETRO-FIT OF VIBRATION ISOLATED FLOOR.
To reduce impact noise transmission through floor/ceiling systems on existing timber, concrete or tiled floors, a floating floor can be constructed on top of the existing floor.
The floating floor should use a resilient damping material. Dense Bradford Rockwool, Glasswool or rubber materials can be used but care is needed to choose a material with the correct stiffness for the application and static load. The services of an acoustic consultant should be engaged to solve floor impact noise problems and for the design of ‘floating floors’.
Floating floors should not be mechanical fixed (nailed or screwed) to the existing floor as this will couple the two floors resulting in very little damping. The resilient material should also be used between the edges of the floating floor and the walls of the building. Skirting boards should also be isolated or separated from the floating floor.
Note the floor/ceiling and floor/door heights may be affected by the use of a floating floor. Doors may also need undercutting if a floating floor is retro-fitted. Therefore where clearances are important, the floating floor height should be kept to a minimum.
250mm minimum 100mm
minimum
C-track or timber batten fixed to soffit Bradford Acoustilag curtain continuous in ceiling area
Suspended ceiling tiles/plasterboard
FIG 7. IMPROVING SOUND TRANSMISSION CONTROL THROUGH CEILING AREA WITH
BRADFORD ACOUSTILAG CURTAIN.
75mm Bradford Reinforced Aluminium Tape 50mm min. overlap Bradford Acoustilag curtain FIG 8. JOINTING A
BRADFORD ACOUSTILAG CURTAIN.
Cut Bradford Acoustilag curtain to allow installation around pipes, ducting etc.
A tight fit should be maintained to ensure acoustic integrity
PENETRATIONS THROUGH BRADFORD ACOUSTILAG CURTAIN.
REDUCING NOISE TRANSMISSION THROUGH TIMBER
FLOOR/CEILING SYSTEMS.
1. Fit Bradford R2.0 (or greater) Floor Batts, or Rockwool/Glasswool Ceiling Batts tightly between ceiling joists.
2. Fix one layer of 13mm or 16mm Gyprock Fyrchek™ plasterboard to furring channels.
3. For better acoustic performance (to reduce airborne noise), choose a ceiling with more mass ie. multiple layers of Gyprock® plasterboard CD or Gyprock Fyrchek™plasterboard.
4. CSR Gyprock®Resilient Mounted Furring Channels will further improve acoustic performance as well as impact isolation.
5. To improve impact isolation of floors, use carpet and good quality thick underlay over timber flooring.
A large range of floor/ceiling systems incorporating alternative acoustic upgrades is detailed in Appendix B of this publication.
Refer to the CSR Gyprock®Fire & Acoustic Design Guide ‘The Red Book’ for additional information on floor/ceiling systems.
REDUCING NOISE TRANSMISSION THROUGH CONCRETE FLOOR/CEILING SYSTEMS.
For concrete floor ceiling constructions, use vibration isolated ceiling hangers or resiliently mounted furring channels to support the plasterboard ceiling.
Products.
• Bradford Floor Batts.
• Bradford Glasswool R2.0, R2.5, R3.0, R3.5, R4.0 Ceiling Batts.
• Bradford Rockwool R1.5, R2.0, R2.5, R3.0 Wall/Ceiling Batts.
• Bradford Glasswool Quietel™(for impact isolation).
Floors.
Improved air-borne sound reduction and impact isolation can be achieved by using floating floors as shown in Figures 11, 12 and 13.
High density, resilient Bradford Rockwool or Glasswool Quietel™ can break the sound and vibration transmission paths while having sufficient compressive strength to support the floating floor and the room contents. Vibrational energy is absorbed in the resilient material rather than transmitted to the building structure. Not only does a floating floor achieve effective structure-borne sound control, but it also reduces the air-structure-borne sound transmission to and from the room below.
The Bradford Fibertex™ Rockwool or Glasswool Quietel™board are laid flat on the floor, ensuring all joints are tightly butted. At the edges of the rooms, the batts continue up the walls. For the concrete floor, waterproof film is then used to cover the batts and a concrete screed floor of suitable thickness is poured.
Carpet and underlay Timber flooring
Gyprock resilient mount Use higher density Gyprock plasterboard (Soundchek or Fyrchek) and/or multiple layers
Furring channel Bradford Glasswool or Rockwool Insulation Timber joists
FIG 9. TYPICAL METHODS FOR IMPROVING ACOUSTIC PERFORMANCE OF A TIMBER
FLOOR/CEILING SYSTEM.
Carpet and underlay Concrete slab floor
Suspended ceiling system Gyprock resilient mount
Higher density Gyprock plasterboard (Soundchek or Fyrchek) and/or multiple layers
Furring channel Bradford Rockwool or Glasswool Insulation
FIG 10. TYPICAL METHODS FOR IMPROVING ACOUSTIC PERFORMANCE OF A CONCRETE
FLOOR/CEILING SYSTEM.
SYSTEM
19/20mm Timber Flooring, 200 x 50 Timber Joists at 450mm centres, 1 layer x 13mm Gyprock plasterboard CD.
Add Bradford R2.0 GOLD BATTS™ between joists.
Add Gyprock Resilient Mounts and Furring Channels at 600mm centres between joists and plasterboard. Add Carpet and Underlay. Add second layer of 13mm Gyprock plasterboard CD
STC/Rw
35
39
52
VIBRATION RESISTANCE.
As Bradford Fibermesh™ Rockwool is stitched to wire mesh, the blankets are especially resistant to fallout under conditions where vibration is present.
Bradford Fibermesh™ is particularly suitable for applications involving both vibration and high temperature where standard bonded insulation materials are less resistant to the effects of vibration.
Products.
• Bradford Glasswool QUIETEL™. • Bradford FIBERTEX™HD Rockwool.
• Bradford FIBERTEX™HD (High Density) Rockwool. • Bradford FIBERMESH™Rockwool.
Plumbing.
Noisy pipe work is a common problem in many buildings. These days, pipe work building trends commonly use inexpensive, lightweight, easily to install mater ials with thin wall thicknesses which are unacceptably noisy. Offices, hotels, apartments and domestic houses can all benefit from reduced soil and waste pipe noise levels. Designers, hydraulic consultants, engineers, plumbers, owners and occupants of buildings should all take steps to insulate pipes and ducts to reduce noise.
Water flowing through commonly used PVC soil and waste pipes is predominantly high frequency noise. To effectively reduce pipe noise, lag the pipes with Bradford Acoustilag™20, 23 or 26 pipe insulation. The 20, 23, and 26 indicate the ‘A-weighted’ [dB(A)] insertion loss achieved by lagging PVC pipes with each of the Bradford Acoustilag™product respectively. (Refer to Appendix B for additional information).
Note, the 20, 23 and 26dB(A) insertion losses only apply to water flowing through PVC pipes which have been correctly lagged with Acoustilag. Using Acoustilag for lagging other noise sources, eg., a fan casing or sheet metal air ducts, will generally result in lower insertion losses to those quoted, as these noise sources have more low frequency noise energy.
To achieve the insertion losses quoted, Bradford Acoustilag™ should be installed with all joins of the lagging overlapped or butted, tightly and taped with Bradford 493 reinforced foil tape. Minimising all the gaps increases the acoustic performance of the lagging.
The Building Code of Australia (BCA) states that: ‘Soil and waste pipes are to be separated 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:
Timber battens
Particleboard or timber board flooring
Structural floor Air gap at wall Bradford
Fibertex Rockwool or Glasswool Quietel Plywood
Sheeting
FIG 11 TYPICAL FLOATING FLOOR – TIMBER OVER CONCRETE. Floor finish 50mm Concrete Wire mesh
Structural floor Waterproof film Bradford
Fibertex Rockwool or Glasswool Quietel
FIG 12 TYPICAL FLOATING FLOOR – CONCRETE OVER CONCRETE. Gyprock plasterboard ceiling Bradford Quietel Board Timber flooring Plywood sheeting Plywood sheeting Bradford Glasswool/Rockwool Ceiling Batts
FIG 13 TYPICAL FLOATING FLOOR – TIMBER OVER TIMBER JOIST CONSTRUCTION.
All equipment is then mounted on the screed floor which is acoustically isolated from the main building structure.
NOTE: The upper plywood layer should not be nailed or screw fixed to the timber below. Instead, it should ‘float’ on the base floor to effectively damp vibration. The floor should also be isolated from the walls. CSR Bradford Insulation recommends consulting an acoustic engineer for the design of floating floor systems.
(a) The pipe must be separated from the rooms of any sole-occupancy unit by construction with an STC not less than:
(i) STC 45 if the adjacent room is a habitable room (other than a kitchen); or
(ii) STC 30 if the adjacent room is a kitchen or any other room’.
The Bradford ‘ACOUSTILAG™ Pipe Insulation’ brochure provides systems using CSR Gyprock® plasterboard to achieve the STC noise criteria specified by the BCA. The STC 50 system specified in that brochure is intended for applications requiring better acoustic isolation from waste pipe noise than is specified in the BCA eg., board rooms, offices, apartments and hotels etc.
To achieve the STC’s specified in Table 6, it is imperative that the pipes be correctly lagged (no gaps to allow noise leakage), and the plasterboard ceiling and walls above be airtight with no gaps into the next room.
It is recommended the services of an acoustic consultant or acoustic engineer be used to achieve specified STC ratings. Penetrations, ducting, light fittings, gaps in ceilings etc., can degrade the acoustic rating of the lagging and ceiling system.
To minimise annoyance from plumbing noise, it is advisable, at the design stage, to avoid placing bathrooms and laundries etc., adjacent to noise sensitive areas. Methods for minimising plumbing noise include: • Select vibration isolated pipe hangers to support pipes
and minimise transmission of vibration into the building structure. These will reduce ‘water hammer’ noise when tur ning the water taps on or off. Alternatively use ARMAFLEX®insulation between pipes and the building structure.
• Use water supply and drain pipes that are oversized, this may reduce line pressure and minimise flow noise. • Where possible, use cast iron waste water pipes in place
of lightweight plastic pipe to substantially reduce plumbing noise. The heavier, stiffer walls of cast iron pipes effectively reduce noise.
• If plastic waste water pipes must be used, use Bradford ACOUSTILAG™to effectively reduce noise. • Insulate all pipes and plumbing that are chased into
brick walls.
• Select quieter plumbing equipment and appliances eg. cisterns, washing machines, clothes dryers etc.
Products.
• Bradford ACOUSTILAG™20, 23 or 26. • Bradford 493 reinforced foil tape. • ARMAFLEX®insulation.
Quietening Box Gutters
& Downpipes.
Box gutters should be insulated with Bradford FLEXITEL™ or SUPERTEL™ Glasswool (25mm thick) faced with heavy duty foil. Insulation can be attached to gutters using 45mm long Bradford self-adhesive fasteners and washers at 300 mm centres. Insulation should be held firmly against the metal surface for maximum dampening. For better noise reduction, use Bradford ACOUSTILAG™20. Noisy downpipes should be insulated with Bradford Glasswool Sectional Pipe Insulation faced with Heavy Duty Thermofoil. Alternatively a 25mm wall thickness ARMAFLEX® pipe insulation or Bradford ACOUSTILAG™20 can be fitted around downpipes.
Products.
• Bradford Glasswool FLEXITEL™or SUPERTEL™. • Bradford ACOUSTILAG™20.
TABLE 6. ACOUSTIC INSULATION SYSTEMS FOR PLUMBING.
System STC/Rw Bradford CSR Gyprock® Bradford
Nº Rating. ACOUSTILAG™ Plasterboard Insulation
BAS 01 30 ACOUSTILAG™20 1 layer 10mm Nil
Gyprock CD™
BAS 02 45 ACOUSTILAG™20 2 layers 13mm CSR 75mm Bradford
Gyprock CD™ Glasswool R1.5
BAS 03 45 ACOUSTILAG™23 2 layers 10mm CSR 75mm Bradford
Gyprock CD™ Glasswool R1.5
BAS 04 50 ACOUSTILAG™23 2 layers 13mm CSR 100mm Bradford
Gyprock CD™ Glasswool, R2.0
BAS 05 50 ACOUSTILAG™26 2 layers 13mm CSR 75mm Bradford
Gyprock CD™ Glasswool R1.5 Refer to the Bradford ACOUSTILAG™brochure for additional information.
Insulation Cladding of
Pipes, Tanks & Vessels.
The insertion loss achieved by cladding pipes, tanks and vessels will depend on a number of factors such as the frequency of the fluid in the pipe the type and mass of the cladding material, the thickness and density of the (rockwool or glasswool) insulation.
It should be noted that some of these cladding systems can actually amplify the noise at lower frequencies, particularly if insulation with a high density is used. This generally happens as the tank now has a larger radiating surface. Therefore it is difficult to predict the insertion loss of cladding systems.
It should be noted that Bradford Rockwool or Glasswool SPI (sectional pipe insulation) will reduce pipe noise but not as effectively as Bradford ACOUSTILAG™ or insulation with a mass barrier. Higher density, means it is less resilient than Bradford ACOUSTILAG™ and more efficiently transfers noise and vibration from the pipe to the cladding/barrier. Note: Bradford ACOUSTILAG™ is not recommended for high temperature applications.
Refer to the CSR Bradford Industrial Insulation Design Guide for installation details of cladding and pipe lagging.
Factories & Engineering
Workshops.
The basic methods by which industrial noise may be controlled are:
• Sound absorption – absorbing the noise using mineral fibre materials which can dissipate the sound energy as heat.
• Sound insulation (enclosing) – containing the noise in one area so that it does not cause annoyance in other areas.
• Vibration damping – damping vibrating surfaces to reduce air borne sound emission.
• Vibration isolation – preventing acoustic energy from entering the building structure.
These processes are illustrated in Figure 14. As the figure shows, treatment of a factory noise problem often involves a combination of the basic processes.
REVERBERATION CONTROL.
Factories and engineering workshops usually are reverberant spaces due to the lack of sound absorption within the space. Areas with multiple noise sources, such as factories, engineering workshops, bottling plants, machine halls, plant rooms etc usually have a high level of reverberant noise often exceeding the safe regulatory noise level of 85dB(A).
The use of sound absorbing materials (such as glasswool and rockwool) to reduce reflected or reverberant sound is the most effective means of reducing overall sound levels in enclosed areas.
CSR Bradford Insulation manufacture a range of rockwool and glasswool products with outstanding sound absorption properties. These products have been tested in acoustic reverberation rooms to determine the sound absorption coefficients presented in the technical data section.
A range of factory-applied facings is available, the most common being:
• black fibreglass tissues (BMF), or ULTRAPHON™ • THERMOFOIL™laminates (solid and perforated).
An extremely effective acoustic absorber for walls and ceilings is Bradford ACOUSTICLAD™ – a roll formed panel, factory lined with Bradford FIBERTEX™ 350 Rockwool. Each panel interlocks with its neighbour forming a structurally reinforced joint.
Bradford ACOUSTICLAD™ offers excellent test results with NRC ranges from 0.9 to 1.05. Contact CSR Bradford Insulation for a brochure or refer to Appendix C for the Bradford ACOUSTICLAD™ absorption coefficients in 1/3octave bands.
Vibration Damping of fan casing reduces sound emission
Insulation reduces sound flow to outside Absorbent Lining
reduces sound level within enclosure
Vibration Isolation Mounting reduces vibration transmission to floor