viracon acoustical glass
DESCRIPTION
Viracon Acoustical Glass is made from combinations of various glass types along with acoustical window frames to help you effectively reduce sound transmission from airplanes, trains, vehicles and other unwanted noises.TRANSCRIPT
putting a damper on noisewe hear you
AIt all starts with taking
your “what if” questions and
turning them into “why not”
answers. Chances are, we‘ve
recommended a solution for a
similar job over the past 35
years. And chances are today,
we can give you a point of view
other fabricators just don’t feel
comfortable talking about. Trust,
confidence, peace of mind—
it’s what acoustical experience,
a broad selection of glazing
options and the technical
expertise to fabricate customized
solutions can do for you. After
all, the last thing we want is for
you to have to make design
changes that compromise your
vision. And your clients’. It’s
simple: when it comes to
working with you on acoustical
glass ideas, we’re good listeners.
Challenge us, you’ll see.
From imaginative aesthetics to strict environmental and energy issues to critical budget
requirements, we know how to help you figure out a way to make it all work. That’s what
being a leader is all about. Architects, designers, contractors and visionaries throughout the
world have come to rely on our proven experience to make Viracon their “go to” company
when it comes to exploring options. And getting answers. The fact is, after 35-plus years,
100,000 buildings and 500,000,000 square feet of glazing installed in some of the world’s
most remarkable buildings, you learn a thing or two about what’s the best thing to do. Today,
we perform more glass fabricating processes at a single site than any other fabricator.
Sit down, tell us your thoughts, challenge us. The sky’s the limit.
San Francisco International Airport
San Francisco, California
Architect: Skidmore, Owings & Merrill LLP
Glazing Contractor: Harmon Ltd.
Photographer: Richard Barnes
2
290822 AcousGlass.qxd:260669 Viracon VSG006.qxd 2/11/09 9:52 AM Page 2
viraconsultingtFIELD SALES REPRESENTATIVES
We’re here to help with design assistance, budget costing, return on
investment costing, spec writing and review as well as act as a liaison
between architects and glazing contractors. We also work closely with
the glazing contractor to offer assistance with initial costs, final pricing
negotiations, product information and job site inspections. Just ask.
ACCOUNT REPRESENTATIVES & CUSTOMER SUPPORT
Call on us to help with quoting, product performance data, pricing, project
coordination, samples and mockups. All it takes is a phone call.
techelpNeed an answer—fast? Our Architectural Technical Services group, along with
our Architectural Design group, can assist you with specification and design
assistance, performance and environmental analyses, structural calculations,
energy payback, hurricane requirements and security threat levels. No problem.
3
290822 AcousGlass.qxd:260669 Viracon VSG006.qxd 2/11/09 9:52 AM Page 3
Viracon acoustical glass
Acoustical Glass
For today’s design professional, selecting the right glass for commercial
buildings can be a challenge. Many factors must be taken into account,
such as meeting the original design concept, as well as solar, optical
and acoustical performance requirements.
While glass is inherently a poor performer when considering its sound
attenuating (sound transmission) characteristics, combinations of
various glass types and acoustical window frames can effectively
reduce sound transmissions.
Sound transmission through building walls and glass is related to the
limp/mass law. Simply stated, the heavier, more flexible the material is,
the better it will be at reducing sound transmission. Since glass is
essentially lightweight and very stiff, it tends to transmit more sound
than other building materials.
Acoustical Barriers
Sound transmission into a building may occur through many sources
other than glass or windows. Consequently, another performance
aspect to consider is the entire wall or building envelope.
While sound may be transmitted through many components of a
building wall, this transmitted sound may be absorbed in varying
degrees by other components within the wall and by the building
itself. When soundwaves strike a wall, a portion of this energy is
reflected, transmitted or absorbed by the wall.
This distribution of sound energy varies as a function of the wall
construction and its components. Porous materials within the wall,
such as fiberglass, mineral wool and foam insulation, tend to absorb
more of the sound energy. This is the result of the frictional drag of
vibrating air molecules as they attempt to pass through the fibers or
structure of the insulating materials—commonly referred to as sound
damping. Sound damping may occur with the building interior, as well
as furniture, wall and floor coverings.
Another condition that can occur in building wall construction is
sound flanking. Flanking is the transmission of sound from one side of
an acoustical barrier to the other through alternative routes—
other than the acoustical barrier. For example, with an exterior wall
there may be a number of alternative flanking paths that affect the
performance of a wall. Some of these include water and steam pipes,
HVAC ducts, electrical conduits, outlets, plumbing, drains, wall vents
and openings (holes or cracks).
Glass as a Sound Barrier
Glass is inherently a “poor performer” when considering sound
transmission characteristics. Fortunately, the glass used in building
construction provides other substantial benefits. As a result, we tend
to find ways to optimize the acoustical performance of glass for
specific applications.
With any material, the sound transmission loss is dependent on its
mass, stiffness and damping characteristics. With a single glass ply, the
4
CONTINUING EDUCATION
We also work with
professional organizations
and firms worldwide to
provide AIA registered
educational seminars. As a
registered provider with the
AIA/Continuing Education
System (AIA/CES), architects
can receive 1.5 continuing
learning units (LU’s)
with AIA/CES, including
health, safety and welfare
credits. You can schedule a
presentation by visiting our
web site at www.viracon.com
or by calling 800-533-2080.
290822 AcousGlass.qxd:260669 Viracon VSG006.qxd 2/11/09 9:52 AM Page 4
only effective way to increase its performance is to increase the thick-
ness, because stiffness and damping cannot be changed. The sound
transmission loss (STL) for a single glass ply, measured over
18 different frequencies, varies depending on glass thickness.
Thicker glass tends to provide greater sound reduction even though
it may actually transmit more sound at specific frequencies. The critical
frequencies may show improvements to sound transmission loss while
the noncritical frequencies actually transmit more sound. This is due
to the three distinct regions in which glass reacts to sound: mass
controlled, resonance controlled and stiffness controlled.
Within the resonance and stiffness regions, greater STL may be
achieved by varying the glass thickness in multiple glass ply construction.
In the mass region, an increase in weight is required.
In addition to the behavior of the glass within these regions, various
glass thicknesses and constructions (laminated, insulating or a
combination of each) have their own specific critical frequency at
which they begin to vibrate. It is at this critical frequency where the
greatest amount of sound transmission occurs.
By evaluating the STL of various tested products, one can optimize
the glass performance by carefully selecting the product that provides
the greatest STL at the range of frequencies most critical to the
building application.
Commercial buildings use a wide variety of glass types, which may
enhance solar control and safety performance. Monolithic glass plies
will provide the lowest acoustical performance levels. Laminated glass
can provide higher acoustical performance levels than monolithic glass
due to the sound damping characteristics of the polyvinyl butyral (pvb)
interlayer used to permanently bond the glass plies together. And,
insulating glass tends to provide the highest STL potential of any glass
product due to the versatility of the product and its ability to combine
monolithic and laminated glass plies.
GLASS CONSIDERATIONS
Glass Thickness
Most glazing systems have practical limits to the thickness and weight
of the glass used. This limit is due to the constraints of the window
frame design. Glass greater than 1" (25 mm) in thickness may not be
practical in standard window framing systems. In some custom window
designs, glass thicknesses up to 1-1/4" (31.7 mm) may be more
practical. And, some thicker glass products may be accommodated
by modifying gasket designs.
Unfortunately, within these thickness limits, only so much can be
achieved when considering the acoustical performance of the glass.
For example, a 1" insulating glass unit may have an ultimate sound
transmission classification (STC) rating of approximately 35. Obtaining
a higher STC rating may be impossible, even if the glass and air-space
thickness is varied, due to the restrictive overall thickness.
Higher STC ratings can be achieved within the 1" overall thickness
by substituting laminated glass plies for monolithic glass plies.
This option has limits even with an overall thickness limit of 1-1/4"
(31.7 mm). Simply stated, STC 40 values are very difficult to achieve
even with insulating glass products limited to a maximum 1-1/4"
(31.7 mm) thickness.
Glazing Orientation
In the interest of appearance, Viracon recommends orienting the
laminate to the interior, offering more glass tint and coating options for
standard 1/4" (6 mm) exterior panes. Since the pvb is a thermoplastic,
its stiffness and damping ability changes with the temperature. In
theory, the laminated pane should be oriented to the interior for cool
climates and to the exterior in warm climates. In laboratory conditions,
Viracon has seen no significant difference in sound attenuation due to
the glazing orientation.
Asymmetrical Insulating Units
Insulating units constructed with equal panes typically exhibit a
resonant frequency during which both panes vibrate together. At this
frequency, sound transmission loss is significantly lower. To counteract
this, you can use marginally different pane thicknesses. For example,
an insulating unit with one 1/4" (6 mm) and one 5/16" (8 mm) pane
exhibits a much higher STC rating.
Airspaces
Generally, larger airspaces demonstrate better sound attenuation,
because of the acoustical separation of the glass panes. If you require
a hermetically sealed insulating unit, the maximum practical airspace
thickness is 3/4" (19 mm).
If you require a larger airspace, a double-glazed application must be
considered, such as both glass panes glazed in separate rabbets. Since
this is not a hermetically sealed unit, this application may exhibit some
condensation in cold climates.
Gas Filled Insulating Units
In theory, a higher density gas in the space between panes should
have a positive effect on acoustical performance. Comparison testing
of standard symmetrical insulating units indicates that common gases,
such as argon or sulfur hexafluoride, had virtually no increased effect
on STC ratings. While some improvement was noted at some
frequencies, resonance effects actually became more pronounced.
Suggested Specifications
You can specify Viracon products, using the MASTERSPEC® Basic
Section “Glass and Glazing” or the MASTERSPEC Supplemental
Section “Decorative Glazing” software.
MASTERSPEC is a comprehensive and unbiased master specification
system produced and distributed by the American Institute of
Architects (AIA) on a licensed user basis. For further information,
call 800-424-5080.
In addition, guideline specifications for Section 08810—Glass
and additional Viracon product information is available through
McGraw-Hill’s electronic and catalog files of Sweets.
Warranty Information
Viracon’s architectural products carry limited warranties. Contact our
Inside Sales Department for copies of our product warranties.
For more information on acoustical glass or additional literature, call
800-533-2080 (E-mail address: [email protected]).
Tabular Data
The following tables itemize the results of acoustical testing of various
monolithic, laminated, insulating and laminated insulating configurations.
Testing was performed on the glass only in standard sizes for comparison
purposes. Since glazing systems affect acoustical performance, a test
should be performed, especially in critical applications.
5
290822 AcousGlass.qxd:260669 Viracon VSG006.qxd 2/11/09 9:52 AM Page 5
STC
Frequency in Hertz (Hz)
Glass Makeup 100 125 160 200 250 315 400 500 630 800 1000 1250 1600 2000 2500 3150 4000 5000
Sound Transmission Loss (dB)
1/8" (3 mm) 19 17 18 21 23 22 24 27 28 30 30 32 34 35 36 33 26 30 30
1/4" (6 mm) 23 25 25 24 28 26 29 31 33 34 34 35 34 30 27 32 37 31 31
3/8" (10 mm) 26 27 27 30 32 31 34 35 36 35 33 30 30 35 38 41 46 48 34
1/2" (12 mm) 26 30 26 30 33 33 34 36 37 35 32 32 36 40 43 46 50 51 36
OITCestimated
25
32
33
29
Frequency in Hertz (Hz)
Glass Makeup 100 125 160 200 250 315 400 500 630 800 1000 1250 1600 2000 2500 3150 4000 5000 STC
Sound Transmission Loss (dB)
GlassPly
PVB
S/S .030".76 mm
1/8"3 mm
.015".38 mm
1/8"3 mm
.030".76 mm
GlassPly
S/S
1/8"3 mm
2.5 mm 2.5 mm
1/8"3 mm
1/8"3 mm
.045"1.14 mm
1/8"3 mm
1/8"3 mm
.060"1.52 mm
1/8"3 mm
3/16"5 mm
.015".38 mm
3/16"5 mm
3/16"5 mm
.030".76 mm
3/16"5 mm
1/4"6 mm
.060"1.52 mm
1/8"3 mm
1/4"6 mm
.015".38 mm
1/4"6 mm
1/4"6 mm
.030".76 mm
1/8"3 mm
1/4"6 mm
.030".76 mm
1/4"6 mm
1/4"6 mm
.045"1.14 mm
1/4"6 mm
1/4"6 mm
.060"1.52 mm
1/4"6 mm
1/4"6 mm
.090" SGP2.29 mm
1/4"6 mm
3/8"10 mm
.030".76 mm
1/4"6 mm
1/2"12 mm
.060"1.52 mm
1/4"6 mm
5/8" HRG-216 mm
(1/4+.050+.080+.050+1/4)
1/2"12 mm
.030".76 mm
1/4"6 mm
1/4" .100" StormGuard™ 1/4"6 mm
2
3
29 29 29 25 27 29 29 31 32 34 34 34 34 35 33 36 39 41 35
27 23 27 24 27 28 29 31 33 35 35 35 33 31 32 37 41 45 33
25 26 28 27 29 29 30 32 34 35 35 36 36 35 35 38 43 46 35
4 27 27 28 28 29 30 32 34 35 36 36 37 36 35 38 43 46 35
25 25 26 29 28 30 30 32 34 35 35 36 36 36 36 39 43 46 35
27 25 26 30 31 31 33 35 35 35 35 33 33 37 41 44 48 51 36
27 27 27 30 31 31 33 34 35 36 36 35 34 37 41 45 49 52 36
27 28 27 30 31 31 33 35 36 37 37 37 36 37 41 44 48 51 37
25 25 27 30 32 32 34 35 35 35 33 32 35 40 43 46 49 51 36
27 28 26 30 31 31 32 34 35 36 36 35 35 36 40 44 48 51 36
25 29 28 30 33 33 34 36 37 37 37 36 37 41 45 48 51 53 38
26 30 27 30 33 33 34 36 37 38 37 36 37 41 45 48 51 54 38
26 29 28 30 33 33 35 36 37 38 38 37 38 41 44 47 51 54 39
31 30 29 31 32 33 33 34 35 35 34 32 34 37 40 42 44 47 36
29 30 28 32 34 35 36 38 38 38 36 38 42 46 49 52 55 57 40
39 41 46 48 50 52 56 39
29 30 29 32 35 35 37 38 38 38 37 41 44 48 50 53 56 56 41
34 32 30 33 34 35 35 37 38 40 4040 41 41 40 42 46 49 49
1 35 33 33 34 36 36 37 36 35 34
32 31 30 31 33 34 34 34 35 36 35 35 37 41 44 47 49 51 37
31
30
31
31
31
32
33
33
32
33
34
34
34
34
1/4"6 mm
.077" Vanceva® Storm
1.95 mm1/4"6 mm
27 30 30 31 31 33 32 33 34 35 35 34 36 40 43 45 47 47 36 33
36
36
36
37
352.53 mm6 mm
OITCestimated
6
MONOLITHIC GLASS (TABLE 1)
LAMINATED GLASS (TABLE 2)
*A PVB (polyvinyl butyral) interlayer is used unless otherwise indicated. SGP is DuPont’s SentryGlas® Plus interlayer. StormGuard is a tradenameof Viracon and incorporates Solutia’s Saflex® HP interlayer. HRG-2 is fabricated with 2 plies of .050" polyurethane and .080" polycarbonate.Vanceva and Saflex are registered trademarks of Solutia. SentryGlas is a registered trademark of DuPont.
290822 AcousGlass.qxd:260669 Viracon VSG006.qxd 2/18/09 1:34 PM Page 6
Frequency in Hertz (Hz)
Glass Makeup 100 125 160 200 250 315 400 500 630 800 1000 1250 1600 2000 2500 3150 4000 5000 STC
Sound Transmission Loss (dB)
GlassPly
AirSpace
1/8"3 mm
1/4"6 mm
1/8"3 mm
3/8"9 mm
1/4"6 mm
1/2"13 mm
GlassPly
1/8"3 mm
1/8"3 mm
1/4"6 mm
1/4"6 mm
1/2"13 mm
5/16"8 mm
1/4"6 mm
1/2"13 mm
3/8"10 mm
5/16"8 mm
1/2"13 mm
5/16"8 mm
1/4"6 mm
9/16"14.5 mm
26 21 23 23 26 21 19 24 27 30 33 36 40 44 46 39 34 45 28
26 23 23 20 23 19 23 27 29 32 35 39 44 47 48 41 36 43 31
27 24 29 22 22 25 30 33 35 38 40 42 42 37 37 43 46 49 35
30 24 29 26 29 33 34 36 39 41 41 40 38 37 39 43 46 48 38
28 26 32 29 29 31 35 37 38 39 41 43 41 40 41 44 47 49 39
26 24 25 31 24 32 32 35 37 39 39 38 36 38 42 44 46 49 37
32 26 25 20 24 29 33 34 38 41 43 46 46 42 36 43 48 53 37
26
26
30
33
34
32
303/16"5 mm
OITCestimated
3/8"10 mm
3/8"10 mm
5/16"8 mm
1/2"13 mm
1/2"13 mm
3/8"10 mm
29 26 26 31 30 37 36 37 39 39 40 37 35 39 43 46 48 49 39
29 23 23 29 31 34 34 35 36 36 35 35 36 40 43 47 49 48 37
34
32
1/4"6 mm
3/4"19 mm
1/4"6 mm
1/4"6 mm
1"25 mm
1/4"6 mm
27 23 28 21 27 29 34 35 37 41 43 45 44 39 39 46 49 52 38
22 19 27 23 31 30 35 35 36 39 41 42 41 36 37 46 51 56 37
31
30
7
INSULATINGGLASS (TABLE 3)
Data based on testing ~36" x 84" glass to ASTM E413-87 in an acoustical wall. Glass size and glazing system will affect STC rating.
Glass Makeup 100 125 160 200 250 315 400 500 630 800 1000 1250 1600 2000 2500 3150 4000 5000 STC
GlassPly
AirSpace
3 mm1/2"
GlassPly
PVB*
1/8"3 mm
.030".76 mm
GlassPly
1/8"3 mm
1/4"6 mm
5/16"8 mm
1/2"13 mm
13 mm
5/32"4 mm
.030".76 mm
5/32"4 mm
1/4"
1/8"
6 mm1/2"
13 mm5/32"4 mm
.060"
3/16"5 mm
1/4"6 mm
1/2"13 mm
3/16"5 mm
.060"1.52 mm
1.52 mm
26 21 29 28 30 34 36 40 42 44 44 44 45 46 47 52 57 58 42
29 24 30 35 35 37 39 39 40 40 40 39 44 48 52 56 59 61 42
30 25 29 33 34 38 42 42 43 44 42 41 42 44 49 52 55 57 43
32 25 29 31 33 35 37 38 39 39 40 41 42 43 43 44 45 46 41
33
35
36
35
GlassPly
PVB*
1/8"3 mm
.030".76 mm
5/32"4 mm
.030".76 mm
1/4"6 mm
.030".76 mm
1/4"6 mm
.030".76 mm
3/16"5 mm
1/4"6 mm
3/4"19 mm
3/16"5 mm
.030".76 mm
21 23 31 35 37 40 42 42 43 42 42 42 44 48 51 55 57 59 44 331/4"6 mm
.060"1.52 mm
1/8"3 mm
1/4"6 mm
3/4"19 mm
32 26 35 35 35 40 41 42 42 43 44 44 45 47 50 56 54 45 44 371/8"3 mm
.030".76 mm1.52 mm
1/4"6 mm
.060"
OITCestimated
Frequency in Hertz (Hz)
Sound Transmission Loss (dB)
DOUBLE LAMINATED INSULATINGGLASS (TABLE 4)
Data based on testing ~36" x 84" glass to ASTM E413-87 in an acoustical wall. Glass size and glazing system will affect STC rating.
*PVB (polyvinyl butyral) interlayer
290822 AcousGlass.qxd:260669 Viracon VSG006.qxd 2/11/09 9:52 AM Page 7
8
INSULATING LAMINATED GLASS (TABLE 5)
*Data based on testing ~36" x 84" glass to ASTM E413-87 in an acoustical wall. Glass size and glazing system will affect STC rating.
*A PVB (polyvinyl butyral) interlayer is used unless otherwise indicated.
SGP is DuPont’s SentryGlas® Plus interlayer.
StormGuard is a tradename of Viracon and incorporates Solutia’s Saflex® HP interlayer.
HRG-2 is fabricated with 2 plies of .050" polyurethane and .080" polycarbonate.
Vanceva and Saflex are registered trademarks of Solutia.
SentryGlas is a registered trademark of DuPont.
Frequency in Hertz (Hz)
Glass Makeup 100 125 160 200 250 315 400 500 630 800 1000 1250 1600 2000 2500 3150 4000 5000
Sound Transmission Loss (dB)
GlassPly
AirSpace
3/16"5 mm
3/8"9 mm
GlassPly
PVB*
1/8"3 mm
.030".76 mm
GlassPly
1/8"3 mm
1/8"3 mm
3/16"5 mm
1/2"13 mm
1/8"3 mm
.030".76 mm
1/8"3 mm
1/4"6 mm
1/2"13 mm
1/8"3 mm
.030".76 mm
1/8"3 mm
1/4"6 mm
1/2"13 mm
1/4"6 mm
.030".76 mm
1/8"3 mm
1/4"6 mm
1/2"13 mm
1/8"3 mm
.060"1.52 mm
3/16"5 mm
1/4"6 mm
1/2"13 mm
3/16"5 mm
.060"1.52 mm
1/4"6 mm
1/2"13 mm
1/4"6 mm
.030".76 mm
1/4"6 mm
5/16"8 mm
5/8"16 mm
3/16"5 mm
.060"1.52 mm
3/16"5 mm
3/16"5 mm
11/16"17 mm
3/8"10 mm
.030".76 mm
3/16"5 mm
1/4"6 mm
3/4"19 mm
3/16"5 mm
.060"1.52 mm
3/16"5 mm
1/4"6 mm
3/4"19 mm
1/4"6 mm
.060"1.52 mm
1/4"6 mm
3/8"10 mm
3/4"19 mm
1/4"6 mm
.060"1.52 mm
1/4"6 mm
1/4"6 mm
1/2"13 mm
1/4"6 mm
.060"1.52 mm
1/4"6 mm
1/4"6 mm
1/2"13 mm 16 mm
3/16" .060" 3/16"1/4"6 mm
5/8"16 mm 5 mm
5/8" HRG-2
1.52 mm 5 mm
3/16"5 mm
1/4"6 mm
1/2"13 mm
27 27 26 24 22 28 32 35 38 38 39 40 42 43 41 45 52 57 37
26 23 25 23 27 31 34 36 38 39 41 43 45 46 43 49 55 55 39
28 20 29 24 26 30 34 36 39 42 43 44 44 41 40 47 52 56 39
28 17 28 29 33 34 38 40 40 41 41 41 41 40 43 49 54 58 40
24 23 28 26 28 33 36 37 39 42 44 46 46 43 44 50 53 55 41
30 29 31 28 31 34 37 39 41 42 44 46 45 44 47 52 55 60 42
31 29 32 30 32 35 38 40 40 42 44 46 47 46 47 52 56 61 43
28 28 34 36 33 40 41 42 43 43 42 40 40 43 49 53 57 61 43
27 27 29 29 30 35 39 40 41 42 43 46 50 52 50 53 57 59 43
28 26 32 30 35 37 40 41 43 44 45 47 47 44 47 53 57 60 44
28 29 36 32 34 39 41 41 41 43 44 45 45 46 47 52 56 61 44
25 31 38 33 37 39 42 43 43 42 40 40 41 56 50 55 58 61 43
29 24 30 29 32 37 40 40 41 42 44 45 44 45 48 53 57 59 42
33 27 33 29 32 36 39 40 42 44 46 47 47 46 47 51 54 57 43
29 24 30 29 32 37 40 40 41 42 44 45 44 45 48 53 57 59 42
32 27 29 28 31 35 37 39 41 42 43 44 43 42 45 50 53 54 41
31
31
31
30
32
36
36
37
35
36
37
37
34
36
35
353/16"5 mm
.030".76 mm
OITCTCSestimated
1/4"6 mm
1/2"13 mm 14 mm
9/16" StormGuard™28 23 30 28 32 35 36 36 37 39 41 43 43 43 45 48 50 49 40 34
1/4"6 mm
1/2"13 mm 14 mm
9/16" SGP 29 24 32 27 32 34 35 34 36 38 40 40 41 41 42 46 48 49 39 34
1/4"6 mm
1/2"13 mm 14 mm
9/16" Vanceva® Storm 29 25 30 27 31 34 35 34 36 38 40 41 42 43 44 47 50 49 39 34
.76 mm3/16"5 mm
3/16"5 mm
1/4"6 mm
1"25 mm
.030" 24 24 31 28 33 36 37 39 39 40 41 41 41 42 43 47 49 47 40 34
1.52 mm1/4"6 mm
1/4"6 mm
3/8"10 mm
1"25 mm
.060" 24 30 33 35 40 41 44 45 45 44 44 44 43 46 50 54 57 58 46 36
3/16"5 mm
1/4"6 mm
7/16"11 mm
3/16"5 mm
.030".76 mm
31 25 30 27 29 34 36 37 39 40 42 43 42 41 44 47 51 51 40 33
290822 AcousGlass.qxd:260669 Viracon VSG006.qxd 2/18/09 9:41 AM Page 8
Glass Makeup
GlassPl y
PVBGlassPl y
AirSpace
GlassPl y
PVB
100
1/4”6 mm
.030”.76 mm
1/4”6 mm
1”25 mm
1/8”3 mm
.030”.76 mm
211/8”3 mm
Glass
1/8”3 mm
.030”.76 mm
1/8”3 mm
1”25 mm
3/1 6” 5 mm
22
28
27
125
33
27
160
37
28
200
38
31
250
42
35
315
43
38
400
45
41
500
44
42
630
44
43
800
44
44
1000
45
45
1250
49
47
1600
53
47
2000
57
45
2500
59
50
3150
62
58
4000
63
61
5000
46
42
1/8”3 mm
.030”.76 mm
1/8”3 mm
2” 3/1 6” 5 mm
24 25 34 33 34 40 41 44 44 46 47 47 48 48 46 50 55 56 45
1/4”6 mm
.030”.76 mm
1/4”6 mm
2” 50 mm
50 mm
3/1 6” 5 mm
27 36 33 33 35 39 41 45 45 46 46 46 49 51 52 56 60 62 46
1/4”6 mm
.030”.76 mm
1/4”6 mm
2” 50 mm
3/8”9 mm
34 37 33 38 40 42 44 48 47 46 45 52 56 51 55 59 61 62 46
1/8”3 mm
.030”.76 mm
1/8”3 mm
4” 100 mm
3/1 6” 5 mm
26 36 34 37 37 43 44 48 49 51 51 50 51 50 47 51 58 60 48
1/4”6 mm
.030”.76 mm
1/4”6 mm
4” 100 mm
3/1 6” 5 mm
30 37 33 38 37 42 45 49 50 51 50 48 50 53 53 57 61 64 49
1/4”6 mm
.030”.76 mm
1/4”6 mm
4” 100 mm
1/8”3 mm
.030”.76 mm
1/8”3 mm
34 38 34 40 41 45 47 51 52 53 53 51 52 55 58 60 62 64 51
1/4”6 mm
.030”.76 mm
1/4”6 mm
4” 100 mm
3/8”9 mm
38 38 33 40 40 43 46 51 52 52 50 45 48 53 56 59 62 64 49
1/2”13 mm
.060”1
1/4”6 mm
4” 100 mm
1/8”3 mm
29 33 31 36 38 43 44 46 47 49 50 52 52 55 59 59 58 60 49
1/4”6 mm
.060”1.52 mm
1/4”6 mm
4” 100 mm
1/4”6 mm
.030”.76 mm
1/4”6 mm
31 39 35 39 41 43 46 51 52 52 49 48 50 54 59 61 63 64 50
1/2”13 mm
.060”1.52 mm
1/4”6 mm
4” 100 mm
1/4”6 mm
.030”.76 mm
1/4”6 mm
31 42 33 40 42 43 46 50 50 50 49 50 52 55 60 62 64 64 50
35
33
35
39
42
39
41
44
44
40
43
43
Frequency in Hertz (Hz)
Sound Transmission Loss (dB)
OITCestimated
STC
.52 mm
9
DOUBLE-GLAZEDAPPLICATIONS (TABLE 6)
1. Table 6 is provided for information only and refers to field-glazed applications. Viracon supplies only the glass components.
Data based on testing ~36" x 84" glass to ASTM E413-87 in an acoustical wall. Glass size and glazing system will affect STC rating.
*PVB (polyvinyl butyral) interlayer.
Frequency in Hertz (Hz)
Glass Makeup 100 125 160 200 250 315 400 500 650 800 1000 1250 1600 2000 2500 3150 4000 5000
Sound Transmission Loss (dB)
GlassPly
AirSpace
GlassPly
AirSpace
GlassPly
1/4"6 mm
1/2"13 mm
1/4"6 mm
1/4"6 mm
1/4"6 mm
3/16" .030" 3/16"5 mm 1.52 mm 5 mm
25 22 29 24 25 29 34 37 40 43 46 48 47 41 41 47 52 58 39 31
1/4"6 mm
1/2"13 mm
1/2"13 mm
1/2"13 mm
26 27 33 31 33 38 39 41 41 43 44 44 44 45 46 50 52 51 43 35
OITCTCSestimated
TRIPLE / CUSTOM INSULATINGGLASS (TABLE 7)
Data based on testing of ~36" x 84" glass to ASTM E413-87 in an acoustical wall. Glass size and glazing system will affect STC rating.
The .030" component is a PVB (polyvinyl butyral) interlayer.
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Sound
Sound is produced when an object vibrates. Trains, planes,
automobiles and other tools of modern society produce sounds that
can be undesirable in our work and home environments. The human
ear can perceive sound as either pleasurable or annoying, depending
on the circumstances surrounding the event.
While the roar of a jet engine may seem acceptable as you travel to a
vacation destination, it may be an extreme annoyance to office workers
located close to the airport. Consequently, glass selection for commercial
building applications becomes very important.
Understanding the relationship of sound and glass allows us to
maximize the acoustical performance of glass in building constructions.
Sound that comes from one particular source may be a combination
of sound transmitted at various frequencies. Therefore, it is imperative
to select a certain glass type that is capable of reducing sound over a
range of different frequencies.
For example, a jet engine may produce sound at very low frequencies
as it starts up, but as it attains greater power it produces sound at
higher frequencies. The glass selection to reduce sound transmission
will need to have a broader range of sound reduction potential.
Figure 1 below illustrates the distribution of typical sounds and their
peak frequencies.
Since sound is produced by an object when it vibrates, the movement
of jet engine parts causes the jet to vibrate. The engine vibration
creates a disturbance in the air, which spreads out in all directions—
much like ripples from a rock dropped in still water. When air particles
are disturbed by a vibrating source, the layer of air nearest the source
follows the back and forth motion of the source. It then causes an air
pressure disturbance.
The initial disturbance gradually spreads out to air particles further
away and at a certain speed, which is known as the speed of sound.
The speed of sound varies slightly with the temperature and humidity,
but is independent of frequency.
The chain reaction of air pressure disturbance, which is a sequence of
air pressure changes (compression and rarefraction) is called a sound
wave. The number of air pressure changes spreading out from the
vibrating source is measured in cycles per second (cps). For example,
500 ripples of air pressure from the vibration is actually 500 cps,
which is the sound frequency. The basic unit of frequency is Hertz (Hz).
Sound Intensity
Sound intensity is the amount of acoustical energy in a sound wave
and is proportional to sound pressure. The most common measure of
sound pressure is sound pressure level (SPL), which is expressed in
decibels, using a compressed or logarithmic scale.
The human ear is capable of detecting very faint and loud sounds.
Differences between sounds can be dramatic and are described as
intensity. The differences in intensity between faint sounds and loud
sounds is similar to the difference in weight of a paper airplane
and a 747 jet.
The ear is not equally sensitive at all frequencies. For example, the
sound pressure level of two different noises may be the same. One
noise may be perceived as being louder if the sound power is
concentrated in a single frequency or a range of frequencies where
the ear is more sensitive. The second noise may have a single
frequency or a range of frequencies where the ear is less sensitive.
The sensitivity of hearing is generally limited to a range of 10 Hz to
20,000 Hz; however, the human ear is most sensitive to sound within
a range of 500 Hz to 8,000 Hz. Beyond this range, our hearing
capability gradually becomes less sensitive.
To accommodate for this sensitivity, sound level meters incorporate a
filtering device. The filtering is designed to correspond to the varying
sensitivity of the human ear to sounds within the audible range of
frequencies. This is referred to as A-weighting. Sound pressure
levels, using the A-weighted meter scale, are identified as dBA.
Sound Pressure Levels
Figure 2 illustrates the correlation between sound intensity or pressure
(cps) and sound pressure level. The sound pressure level is an easy
way of classifying sound intensity. Sound pressure levels are listed in
decibels (dB). Notice that a sound pressure level of 0 dB does not
mean there is no sound (see Figure 2). Instead, it means that there
is no sound detectable by a person with normal hearing.Whenever
the sound pressure level increases 10 dB, the sound intensity increases
by a factor of ten.
Under typical conditions, an individual with normal hearing cannot
detect a change in sound pressure of 1-2 dB. A difference in sound
10
Figure 1
Bass Drum
Middle C
Ringing Telephone
Television
Male VoiceFemale Voice
Speech Intelligibility
Speech Privacy
Truck
Auto Horn
Freight Train
Jet Aircraft
Propeller Aircraft
Electric Motor
Punch Press
SOU
RCE
FREQUENCY DISTRIBUTION OF TYPICAL SOUNDS
50 100 200 500 1000 2000 5000 10000
FREQUENCY IN CYCLES PER SECOND
terms and definitions
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pressure of 3 dB is barely perceptible if the change is sustained and no
time lapse occurs. A change of 5 dB is clearly detected and a change
of 10 dB is perceived as twice or half the noise level.
Sound Transmission Loss
To determine the acoustical performance of glass, it is important to
consider the application in which it will be used, as well as the
framing system that supports the glass.
For each sound frequency, the reduction in sound produced by a
sound barrier is called the sound transmission loss (STL) at that
frequency. When glass is used on an exterior wall, its STL at various
frequencies is used to determine the effectiveness of the glazing.
Viracon has tested various glass configurations to determine the
sound transmission loss over a range of 100 Hz to 5,000 Hz. These
tests help designers evaluate and select the best glass to provide
greater sound transmission loss at those frequencies where the
greatest amount of noise potential exists.
As indicated earlier, the selection of window framing systems is
important when reducing sound transmission. Window framing
systems are evaluated for thermal characteristics, as well as air and
water infiltration. Certain window framing systems may perform
better acoustically than others as a design function. One important
attribute to consider is the air tightness of the system. Window
framing systems that allow greater amounts of air infiltration also
allow greater sound transmission.
Dry glazed window systems, which use rubber gaskets as weather
seals, may not be as effective at reducing sound transmission as
systems that use wet seals (gunable sealants). The combination of wet
seals with butyl or open cell foam dramatically reduces the potential
for air infiltration; thus, flanking sound transmission.
In addition, sound pressure impinging on the window framing will
cause it to vibrate, transmitting sound to the building interior.
Consequently, the window glass performance cannot solely be relied
upon to reduce sound transmission to the building interior. The sound
transmission of the window framing will result in higher levels of
sound transmission through the glass and wall.
STC RATING
Sound Transmission Class Rating
When glass is used on the building interior, the sound transmission
classification (STC) value can be used to categorize the glass
performance. The STC rating is a single-number rating system for
interior building partitions and viewing windows.
The STC rating is derived by testing in accordance with ASTM E90,
“Laboratory Measurement of Airborne Sound Transmission of Building
Partitions”. The STC value is achieved by applying the Transmission
Loss (TL) values to the STC reference contour of ASTM E413,
“Determination of Sound Transmission Class”. The STC rating is a basis
for glass selection. Its original intent was to quantify interior building
partitions, not exterior wall components. As a result, it is not
recommended for glass selection of exterior wall applications, since
the single-number rating was achieved under a specific set of
laboratory conditions.
Laboratory measurements of sound transmission loss and subsequent
STC ratings are dependent on a number of factors present at the time
of testing. The laboratory test is an “ideal test condition” used to
minimize extraneous factors from the test results. Cautious
consideration must be given to the laboratory “test results” versus
actual job conditions.
The test frame aperture size available at most testing laboratories
may also be limited and standardized to facilitate the installation of
popular products. As a result, the standardized aperture size may be
inappropriate for all products tested nor representative of actual
building conditions.
It is not recommended to estimate STC ratings based on the
performance of tested products in comparison to “new”
configurations. This is because of the critical relationship of glass
construction and its reaction to sound at various frequencies.
Minor changes to the glass construction and air-space thickness may
increase sound transmission loss at some frequencies and decrease it
in others. Depending on where the critical frequencies exist for a
particular construction, the STC rating could actually be lower even
though the glass construction was thought to have been improved
with minor modifications.
OITC RATING
Outside-Inside Transmission Class Rating
This rating is used to classify the performance of glazing in exterior
applications. This is based on ASTM E-1332 Standard Classification for
the Determination of Outdoor-Indoor Transmission Class. While STC
rating is based on a ‘White’ noise spectrum, this standard utilizes a
source noise spectrum that combines Aircraft/Rail/Truck traffic and
is weighted more to lower frequencies.
11
COMPARISON OF SOUND INTENSITY AND SOUND PRESSURE LEVEL
Sound Intensity Sound Pressure Typical Soundsor Pressure Level in dB
1,000,000,000,000 120 Thunder Clap100,000,000,000 110 Nearby Riveter10,000,000,000 100 Boiler Factory/Subway1,000,000,000 90 Loud Street Noise/Noisy Factory100,000,000 80 Noisy Office10,000,000 70 Average Street Noise1,000,000 60 Average Radio/Average Office100,000 50 Average Conversation10,000 40 Quiet Radio/Private Office1,000 30 Average Auditorium100 20 Quiet Conversation/Whisper10 10 Soundproof Room1 0 Threshold of Audibility
Figure 2
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800 Park Drive, Owatonna, MN 55060507.451.9555 800.533.2080 (Toll Free)507.444.3555 FAX (Within U.S.A.) 507.451.2178 FAX (Outside U.S.A.)E-Mail: [email protected] Internet address: http://www.viracon.com
This publication describes Viracon’s architectural acoustical glass products
to help you analyze possible design options and applications. To obtain
warranty information, contact Viracon’s Architectural Inside Sales or
Technical Services Department.
The information contained in this publication is presented in good faith.
It is believed to be accurate at the time of publication. Viracon reserves the
right to change product specifications without notice and without
incurring obligation.
Viraconsulting is a registered trademark of Viracon.
MASTERSPEC is a registered trademark of the American Institute of Architects.
© 2009 Viracon. All rights reserved.VSG-006I VRJC0209C O U N C I L
U.S
.G
R
E E N B U I LD
I NG
ME M B E R
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