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CFP PAN – Lami

Sound Control Edition 2.0

October 2008

Laminated

Glass Sound

Control

Using Laminated Glass for Sound Control in Residential Applications

S e c t i o n 1 UNDERSTANDING SOUND TRANSMISSION

INTRODUCTION

When outdoor sound energy comes in contact with traditional window and door systems, vibration occurs. This vibration enables partial transmission of the outdoor sound energy through the fenestration system and into the indoor environment. This Product Application Note is intended to provide an overview of the principles of sound transmission and the use of laminated glass to reduce unwanted noise transmission across residential glazing systems.

MEASURING SOUND TRANSMISSION

There are two important components of sound. Sound has frequency -- the number of wavelength cycles per second -- and amplitude, which is related to its loudness. The frequency is measured in Hertz (Hz), while the amplitude is represented by its Sound Pressure Level (SPL), measured in decibels (dB). The frequency is what gives a sound its pitch, with high-pitched sounds such as typical human conversation having a higher frequency and shorter wavelength, and low-pitched sounds such as automobile traffic having a lower frequency and longer wavelength.

The effective sound insulation of a window depends on its area and on its sound transmission loss (the attenuation of the transmitted sound energy measured in decibels). Transmission loss is measured over a wide range of frequencies. The measurements are usually combined into a single-number rating, such as Sound Transmission Class or STC (ASTM E413), to make it possible to rank products. Sound Transmission Class was developed as a rating system based on mid- or high-frequency noises that are typical of indoor sources such as speech, radio and television noise or household appliances. The higher the number, the higher the sound transmission loss or noise reduction.

Although STC is also commonly applied to building envelope components such as windows, ASTM E413 specifically states that the STC calculation should not be used to evaluate partitions exposed to machinery, industrial and transportation noise such as motor vehicles, aircraft and trains.

In order to correlate more closely with the lower-frequency noises that are typical of outdoor sources such as traffic, airport noises, and industrial processes, the Outdoor

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CFP PAN – Lami

Sound Control Edition 2.0

October 2008

Laminated

Glass Sound

Control

Indoor Transmission Class rating (OITC) was developed, and became ASTM E1332. Although not as widely recognized within the Window and Door industry as STC, OITC is considered by many experts to be a more appropriate measure of transmission loss in residential applications.

S e c t i o n 2 MANAGING SOUND TRANSMISSION OF WINDOWS

OUTDOOR SOUND / INDOOR SOUND

Reducing sound transmission through windows and doors is a function of component materials, system design, and installation. Proper installation is assumed for this discussion. Although modifying the design of a glazing system without changing component materials is an option to reduce sound transmission, this approach involves significantly increasing the physical dimensions of the window. The redesign typically involves widening the airspace to as much as four inches in a double-glazed insulating glass unit; and as such this technique is often rejected as impractical.

Changing component materials is the most common technique used to reduce sound transmission through windows and doors. Understanding the basic science of sound transmission is helpful in identifying the best potential options for reducing the sound transmission of glazing system components.

Sound transmission loss in a glazing system is dependent on the mass, damping and stiffness of the glazing components. While it is not practical to increase glass stiffness (note that glass stiffness is not the same as glass strength, which can be increased through heat-treatment), it is generally understood that increasing glass thickness (mass) is an effective way to decrease sound transmission. Unfortunately, traditional residential fenestration is limited in its ability to incorporate meaningfully greater glass thickness due to dimensional and weight limitations. Increasing the airspace between glass lites is also a technique that falls within the category of increased mass; however, traditional residential design is also limited in its ability to incorporate gap-widths that provide meaningful reductions in sound transmission.

Glass damping is therefore the only remaining option for reducing sound transmission in residential fenestration. Generally, glass has very low inherent damping, so adding damping elements such as the interlayer used to make laminated glass is usually the most cost-effective option. The interlayer is inherently damping, and when it is placed between two pieces of glass it absorbs sound waves so they are not transmitted to the second lite of glass, and therefore not transmitted indoors. Laminated glass has proven to be a superior barrier to noise than monolithic glass of equal thickness. The ‘coincidence effect’ when monolithic glass resonates, or vibrates at certain

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CFP PAN – Lami

Sound Control Edition 2.0

October 2008

Laminated

Glass Sound

Control

frequencies is also considerably reduced with laminated glass, and the noise reduction performance of insulating glass units can be greatly improved by incorporating at least one layer of laminated glass.

Table 1— Approximate STC and OITC ratings for common residential glazing packages with traditional PVB interlayer. Enhanced sound attenuation may be achieved using specialty interlayer material.

Table 1. Acoustical Performance of Typical Residential Glazing Packages

Configuration STC Rating OITC Rating

Monolithic Glass 3mm 27 24

5/8" Standard IG Unit 3mm

[ 0.50"AS ] 3mm

31 26

1/4" Laminated Glass 3mm / 0.030" PVB / 3mm 34 30

5/16" Laminated Glass 3mm / 0.090" PVB / 3mm 35 32

7/8" Laminated IG Unit 3mm

[0.50"Air Space] 3mm / 0.030" PVB / 3mm

37 31

1" Double Laminated IG Unit 3mm / 0.030" PVB / 3mm

[0.50" Air Space] 3mm / 0.030" PVB / 3mm

40 33

Each of these rating methodologies gives slightly different classification numbers, so it is important to consider surrounding environmental conditions to ensure that the appropriate Sound Transmission Loss rating is emphasized. It is also important to recognize that the STC or OITC rating of a glass product does not represent the rating of the window system. The window system includes many materials other than glass, including the window sash and frame, and the insulating glass unit spacer material and sealant. In addition, proper installation is critical to ensure that sound does not enter through poorly fitted components.

While STC and OITC ratings are published for various glass configurations, accurate ratings for the glazing system can only be determined by full window system testing. It is best to enlist the assistance of an acoustic consultant to coordinate the design, testing, and interpretation of test-results, prior to making final design decisions.

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CFP PAN – Lami

Sound Control Edition 2.0

October 2008

Laminated

Glass Sound

Control

S e c t i o n 3 ADDITIONAL RESOURCES

INCORPORATING GUARDIAN RESIDENTIAL LOW-E INTO LAMINATED GLAZING CONFIGURATIONS

There are two ways to use low-E coatings with laminated glass –either embedded, or exposed. In this context, embedded refers to a configuration in which the coating(s) are in direct contact with the interlayer; exposed refers to coatings that are positioned facing the airspace of an IG unit. Positioning of low-E coated lites within a laminated glass configuration does not effect sound attenuation; however there are thermal and aesthetic implications that should be considered when designing any laminated glazing package.

The thermal performance (U-factor) improvement that is associated with the use of low-E coatings only applies to laminated configurations in which the low-E coating is exposed to a sealed airspace. When a low-E coating is embedded in a laminated configuration, the thermal performance of the configuration is approximately the same as it would be without a low-E coated lite.

Embedded and exposed coatings both provide the solar control (SHGC) benefit associated with the low-E coating; however, the resulting SHGC can vary significantly depending on the glazing configuration. An additional consideration when determining the preferred positioning of low-E coatings within a glazing system is the potential for thermal stress. Although typical combinations of glass, INTERLAYER, and Guardian’s Residential Low-E coatings do not result in glass temperatures that are associated with thermal breakage, thermal and solar simulations should be performed by a qualified party prior to finalizing configuration design in order to fully understand the SHGC values and the potential for heat build-up within the glazing system.

Guidelines for use and positioning of Guardian’s Residential Low-E coated glass in laminated configurations are provided for reference in Table 2. Note that mock-ups are advised for aesthetic reasons with some products when they are positioned on specific surfaces, as these configurations are likely to have more pronounced color properties.

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CFP PAN – Lami

Sound Control Edition 2.0

October 2008

Laminated

Glass Sound

Control

Table 2— Guidelines for use and positioning of Guardian’s Residential Low-E coated glass in laminated configurations.

Illustration LegendGlassCoatingInterlayerSpacer

Surface #2

Surface #3

Surface #2

Surface #3

Surface #4

Surface #5

Performance Plus II Yes No YesMock-up Advised

YesMock-up Advised

YesMock-up Advised

ClimaGuard 75/68 Yes No No No Yes Yes No No

ClimaGuard 71/38 Yes No YesMock-up Advised

Yes Yes YesMock-up Advised

ClimaGuard 70/36 Yes No YesMock-up Advised

Yes Yes YesMock-up Advised

ClimaGuard 55/27 Yes No Yes No Yes Yes Yes No

Performance Plus II HT No Yes YesMock-up Advised

YesMock-up Advised

YesMock-up Advised

ClimaGuard DHT No Yes Yes No YesMock-up Advised

Yes No

ClimaGuard HT No Yes YesMock-up Advised

Yes Yes YesMock-up Advised

ClimaGuard 55 HT No Yes Yes No Yes Yes Yes No

Table 2. Laminated Coated Surface Guide

Laminated (Monolithic) IGU Lami (Inboard lami lite)

Coating

Annealed or Temper-Coated

Low-E

Heat-treatable

Low-E

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CFP PAN – Lami

Sound Control Edition 2.0

October 2008

Laminated

Glass Sound

Control

Air Argon

Small Missile

Large Missile

Uncoated 1/8" annealed glass - - - - 27 24 90% 74% 0.87 1.00 n/a - -Uncoated 1/8" tempered glass + + - - 27 24 90% 74% 0.87 1.00 n/a - -

UncoatedLami glass - 2.7mm

[0.030" PVB] Lami glass - 2.7mm

+ + - - 34 30 89% 0% 0.81 1.00 n/a - -

Uncoated + + - - 34 30 89% 0% 0.80 1.00 n/a - -ClimaGuard 75/68 #3 n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/aClimaGuard 71/38 #2 + + - - 34 30 70% 0% 0.41 1.00 n/a - -ClimaGuard 70/36 #2 + + - - 34 30 69% 0% 0.38 1.00 n/a - -ClimaGuard 55/27 #2 + + - - 34 30 59% 0% 0.33 1.00 n/a - -

Uncoated + + + + 35 31 88% 0% 0.79 0.98 n/a + -ClimaGuard 75/68 #3 n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/aClimaGuard 71/38 #2 + + + + 35 31 70% 0% 0.40 0.98 n/a + -ClimaGuard 70/36 #2 + + + + 35 31 69% 0% 0.38 0.98 n/a + -ClimaGuard 55/27 #2 + + + + 35 31 58% 0% 0.33 0.98 n/a + -

Uncoated + + + + 35 32 88% 0% 0.78 0.96 n/a + +

ClimaGuard 75/68 #3 n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/aClimaGuard 71/38 #2 + + + + 35 32 70% 0% 0.40 0.96 n/a + +ClimaGuard 70/36 #2 + + + + 35 32 68% 0% 0.37 0.96 n/a + +

ClimaGuard 55/27 #2 + + + + 35 32 58% 0% 0.33 0.96 n/a + +

Uncoated - - - - 31 26 82% 59% 0.78 0.48 n/a - -ClimaGuard 75/68 #3 - - - - 31 26 75% 46% 0.69 0.32 0.27 - -ClimaGuard 71/38 #2 - - - - 31 26 71% 24% 0.39 0.29 0.24 - -ClimaGuard 70/36 #2 - - - - 31 26 70% 30% 0.36 0.29 0.24 - -ClimaGuard 55/27 #2 - - - - 31 26 55% 18% 0.27 0.29 0.24 - -

Uncoated + + - - 31 26 82% 59% 0.78 0.48 n/a - -ClimaGuard 75/68 #3 + + - - 31 26 75% 46% 0.69 0.318 0.27 - -ClimaGuard 71/38 #2 + + - - 31 26 71% 24% 0.39 0.29 0.24 - -ClimaGuard 70/36 #2 + + - - 31 26 70% 30% 0.36 0.293 0.24 - -ClimaGuard 55/27 #2 + + - - 31 26 55% 18% 0.27 0.289 0.24 - -

Uncoated + + - - 37 31 81% 0% 0.75 0.47 n/a - -ClimaGuard 75/68 #3 + + - - 37 31 75% 0% 0.67 0.314 0.27 - -ClimaGuard 71/38 #2 + + - - 37 31 70% 0% 0.39 0.287 0.24 - -ClimaGuard 70/36 #2 + + - - 37 31 68% 0% 0.36 0.29 0.24 - -ClimaGuard 55/27 #2 + + - - 37 31 54% 0% 0.27 0.285 0.24 - -

Uncoated + + + + 37 31 80% 0% 0.75 0.466 n/a + +

ClimaGuard 75/68 #3 + + + + 37 31 74% 0% 0.67 0.311 0.27 + +ClimaGuard 71/38 #2 + + + + 37 31 69% 0% 0.38 0.285 0.24 + +ClimaGuard 70/36 #2 + + + + 37 31 68% 0% 0.36 0.288 0.24 + +

ClimaGuard 55/27 #2 + + + + 37 31 53% 0% 0.27 0.281 0.23 + +Uncoated + + + + 37* 31* 80% 0% 0.74 0.462 n/a + +

ClimaGuard 75/68 #3 + + + + 37* 31* 74% 0% 0.67 0.309 0.26 + +ClimaGuard 71/38 #2 + + + + 37* 31* 69% 0% 0.38 0.283 0.23 + +ClimaGuard 70/36 #2 + + + + 37* 31* 68% 0% 0.36 0.285 0.24 + +

ClimaGuard 55/27 #2 + + + + 37* 31* 53% 0% 0.27 0.281 0.23 + +

Table 5. Performance and Compliance of Low-E Enhanced Laminated Glass Configurations

Configuration

1/8 glass [1/2" AS ]

1/4" Lami (0.030")

1/8 glass [1/2" AS ]

1/4" Lami (0.060")

Monolithic Clear Glass [1/8"]Tuv% SHGC

U+Factor HurricaneCPSC Cat. I

1/8 glass [1/2" AS ]

1/4" Lami (0.090")

Monolithic Laminated Glass [5/16"]

Standard Insulating Glass Unit [3/4"]

Laminated Insulating Glass Units (3/4" OA, Laminated Glass Inboard)

1/8" annealed glass [1/2" AS]

1/8" annealed glass

1/8" glass [0.090" PVB] 1/8" glass

1/8" tempered glass [1/2" AS]

1/8" tempered glass

1/8" glass [0.030" PVB] 1/8" glass

1/8" glass [0.060" PVB] 1/8" glass

OITCT vis

%CPSC Cat. II

ASTM F1233 Class 1

UL 972 STC

PERFORMANCE AND COMPLIANCE OF LOW-E ENHANCED LAMINATED GLASS CONFIGURATIONS (REFERENCE TABLE NOTES ON THE FOLLOWING PAGE)

Table 5. Performance and Compliance of Low-E Enhanced Laminated Glass Configurations

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CFP PAN – Lami

Sound Control Edition 2.0

October 2008

Laminated

Glass Sound

Control

LAMINATED GLASS CONFIGURATION TABLE NOTES

The information contained in this table is based on center-of-glass performance. Total window system simulation and testing is necessary to determine window system performance and compliance.

Thermal performance modeling must include the anticipated installation angle in order to accurately predict thermal performance.

– Indicates that the composition may not meet requirements of the test standard when annealed glass is used.

+ Indicates that the composition may provide the level of protection shown with correct installation and framing.

CPSC Cat. I and Cat. II: CPSC 16 CFR 1201 Safety Standard for Architectural Glazing Materials

ASTM F-1233 Class 1: Standard Test Method for security glazing materials and systems.

UL 972: Burglary resistant glazing material.

Sound Transmission Class (STC): Expressed in laboratory-measured dB, indicating the level of sound insulation of interior construction material.

Outdoor-Indoor Transmission Class (OITC): Expressed in laboratory-measured dB, indicating the acoustic performances of exterior doors and windows.

ADDITIONAL GUARDIAN LAMINATED GLASS PRODUCT APPLICATION NOTES

Using Laminated Glass for Solar Control and Energy Management in Residential Applications – CFP PAN Lami Solar control and Energy Management.

Using Laminated Glass for Safety and Burglary-Resistance in Residential Applications – CFP PAN Lami Safety and Burglary-Resistant.

Using Laminated Glass for Hurricane-Impact and Windborne Debris-Resistant Applications – CFP PAN Lami Hurricane and Windborne Debris

Using Laminated Glass for Sloped and Overhead Glazing – CFP PAN Lami Sloped Overhead Glazing and Skylights.

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CFP PAN – Lami

Sound Control Edition 2.0

October 2008

Laminated

Glass Sound

Control

LAMINATED AND COATED GLAZING INSPECTION AND QUALITY STANDARDS

Table 4. ASTM C1172-03 – Maximum Allowable Laminating Process Blemishes

Central Outer Central Outer Central OuterBoil (bubble)

1/16 (1.6) 3/32 (2.4) 1/8 (3.2) 3/16 (4.8) 1/4 (6.4) 1/4 (6.4)

Blow-in; edge boil

n/aCE: 1/4 (6.4)

EE: 1/32 (0.8)n/a

CE: 1/4 (6.4) EE: 1/16 (1.6)

n/aCE: 5/16 (8.0) EE: 3/32 (2.4)

Fuse 1/32 (0.8) 1/16 (1.6) 1/16 (1.6) 3/32 (2.4) 3/32 (2.4) 5/32 (4.0)

Hair, lint (single strand)

light intensity

medium intensity

light intensity

medium intensity

medium intensity

medium intensity

Inside dirt (dirt spot)

1/16 (1.6) 3/32 (2.4) 3/32 (2.4) 5/32 (4.0) 1/8 (3.2) 3/16 (4.8)

Lint - areas of concentrated lint

light intensity

light intensity

light intensity

light intensity

light intensity

light intensity

Separation, discoloration

none none none none none none

Short Interlayer; unlaminated area chip

n/aCE: 1/4 (6.4)

EE: 1/16 (1.6)n/a

CE: 1/4 (6.4) EE: 3/32 (2.4)

n/aCE: 1/4 (6.4) EE: 1/4 (6.4)

Interlayer scuff; streaklight

intensitylight

intensitylight

intensitylight

intensitylight

intensitylight

intensity

6. Light Intensity: barely noticeable at 36 inches (914.4 mm).7. Medium Intensity: noticeable at 36 inches (914.4 mm) but not at 11 feet (3,352.8mm).8. All imperfections noted should be separated by a minium of 12 inches (305mm).

2. Central Area is defined by an oval / circle, whose axis, when centered, is <80% of the overall dimension.3. Outer Area is defined as the area outside of the central area.4. CE: covered edge of glass edge bite.5. EE: exposed edge (if CE or EE is unknown, use CE tolerance).

ASTM C1172-03 - Maximum Allowable Laminating Process Blemishes: Inches (mm)

Notes:1. Inspection must be performed with the glazing system in a vertical orientation.

Up to 25 ft.2 (2.5m2) 25 - 75 ft.2 (2.5 - 7.0m2) Over 75 ft.2 (7.0 m2)Blemish

Table 5. Quality Specifications for Coated Vision Glass

Blemish Central Area Outer Area

Pinhole 1/16" (1.6mm) Max. 3/32" (2.4mm) Max.

Spot 1/16" (1.6mm) Max. 3/32" (2.4mm) Max.

Coating Scratch 2" (50mm) max length 3" (75mm) max length

Mark / Contaminant 2" (50mm) max length 3" (75mm) max length

Coating Rub None Allowedlength + width not to exceed

3/4" (19mm)Crazing None allowed None allowed

Corrosion None Allowed None allowedNotes:

ASTM C1376-03 - Quality Specifications For Coated Vision Glass

1. These specifications apply to cut size glass only. For specifications of stock size glass contact the manufacturer.2. The glass shall be inspected, in transmission, at a distance of 10 ft.(3m) at a viewing angle of 90 degrees to the specimen against a bright uniform background. If a blemish is readily apparent under these viewing conditions, the above criteria applies.

5. No more than two readily apparent blemishes are allowed in a 3-in. (75mm) diameter circle, and no more than five readily apparent blemishes are allowed in a 12-in. (300mm) diameter circle.

3. Central Area is defined by a square / rectangle, defined by the center 80% of the length and 80% of the width dimensions centered on a lite of glass.4. Outer Area is defined as the area outside of the central area

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CFP PAN – Lami

Sound Control Edition 2.0

October 2008

Laminated

Glass Sound

Control

SELECT ACOUSTICAL TESTING AND CLASSIFICATION STANDARDS

E90 Standard Test Method for Laboratory Measurement of Airborne Sound Transmission Loss of Building Partitions and Elements

ASTM E413 Standard Classification for Rating Sound Insulation

ASTM E1332 Standard Classification for Determination of Outdoor-Indoor Transmission Class

ASTM E1433 Standard Guide for Selection of Standards on Environmental Acoustics.

E1425 Standard Practice for Determining the Acoustical Performance of Exterior Windows and Doors

AAMA 1801 Voluntary Specification for the Acoustical Rating of Windows, Doors and Glazed Wall Sections.

GUARDIAN MANUFACTURES LAMINATED GLASS IN THE FOLLOWING LOCATIONS

Guardian Galax

110 Jack Guynn Drive, Galax, VA 24333

Phone: (276) 236-5196

For additional information regarding storage, handling, fabrication, Limited Warranty coverage or use of any Guardian glass product, please contact the Guardian Customer Engineering Group at 888-521-9734.