PROCEEDINGS of the
23rd International Congress on Acoustics
9 to 13 September 2019 in Aachen, Germany

Sound Insulation of Monolithic or Laminated Single- and DoubleGlazing Panels
Fangliang Chen 1, 2; Yihe Huang 1; Tejav DeGanyar 1
1

Virtual Construction Lab of Schüco, New York, NY
2

Columbia University, New York, NY

ABSTRACTSound transmission characteristics of single or multiple panels as sound insulation components in buildings
have been studied extensively, and numerous models have been developed over the past few decades. Thoughmost of them have been validated individually with specific test results in their developing phases, evidence
showed that considerable discrepancy exits from one model to another. By applying many existing models
onto glazing panels such as windows, doors, or building facades, the authors found that most of them unable
to accurately predict their sound insulation performance. Apparent discrepancy up to 3-5 dB in terms of
OITC/STC index was even found between the predictions by commercial software and those well-recognized
test results. More accurate theoretical models are highly demanded in the industry to guide the design of realpractice. To address this need, revisits of most existing theoretical models were made by the authors, andextended models are accordingly developed and presented in this study to provide more accurate predictions
on the acoustic performance of monolithic or laminated single- and double-glazing panels. Test results
collected from literature as well as conducted by the authors are further provided to validate the proposedmodels.
Keywords: Sound radiation, Insulation, Sound Transmission Loss, glazing panel, laminated glass

1. INTRODUCTION
The acoustic performance of building facades such as window, door, and curtain wall in terms of
their sound insulation is one of the critical calibers to the quality of Schüco products across the world.
Architecture designer, general engineer or contractor are heavily relying on commercial software toestimate the acoustic performance of certain designed products. However, majority of them do notnecessarily have the knowledge sensing whether the estimations provided by the software reflecting
the reality of the product or will meet the need from customers. In this sense, the accuracy of thetheoretical models behind any commercial software plays a considerable role in designing a product.
Over the past few decades, numerous models have been developed to predict the soundtransmission characteristics of single or multiple layer panels. In many theoretical models, various
constants or parameters were empirically determined by best matching the predictions with test results.
As a consequence, a model might work well for a certain type of materials while not applicable toothers. Moreover, evidence showed that considerable discrepancy exits from one model to another.
By applying many existing models onto single or multiple glass panels, the authors found that mostof them unable to accurately predict their sound insulation performance. Appar ent discrepancy up to
3-5 dB in terms of OITC/STC index was found between the predictions by commercial software andthose well-recognized test results, which is even higher for multiple layer laminated glass panels.
In this study, based on existing theoretical models of sound transmission loss on single and multiple
panels, extended models are developed and summarized for a single layer of laminated glass and adouble layer of insulating-laminated glass panels. Test results collected from literature as well as
FChen@schuco-usa.com

1224

conducted by the authors are further provided to validate the extended models.

2. SINGLE LAYER GLAZING PANEL
2.1

Monolithic Glazing

2.1.1 Current models in the literature
From Davy’s studies (1–3), the diffuse field sound transmission coefficient of a single rectangularhomogeneous panel with dimensions of ܽ ൈ ܾcan be calculated asଶଶଶ‫ ߬ ۓ‬ൌ ʹ ൭ ൭ ͳ ൅ ඥͳ ൅ ‫ ݍ‬൱ ൅ ͳ ݈݊ ൭݄ ൅ ඥ݄ ൅ ‫ ݍ‬൱൱ ǡ݂ ൑ ݂ܿ
௟
ߣ
ߙ଴ଶ
ۖ
‫ ݌‬൅ ඥ‫݌‬ଶ ൅ ‫ݍ‬ଶ‫ ݌‬൅ ඥ‫݌‬ଶ ൅ ‫ݍ‬ଶ

߬ൌ

(1)

ʹߙ଴ ൫ͳ െ ‫ݎ‬௙ ൯
‫۔‬
ʹߙ଴
ߪ଴ଶ
ۖ߬௛ ൌ ʹߙ ‫ ݎ‬ሺߪ ൅ ߙ ߟሻ ቌܽ‫ ݊ܽݐܿݎ‬൬ߪ ൅ ߙ ߟ ൰ െ ܽ‫ ݊ܽݐܿݎ‬ቆ ߪ ൅ ߙ ߟ ቇቍ ǡ ݂ ൐ ݂ܿ
଴ ௙ ଴
଴
଴
଴
଴
଴
‫ە‬

where

the radiance efficiency ߪ଴ in highǡ݂݅‫ ݌‬൑ ݃ ൑ ͳ೙ ೙ඥ௚ ା௤ ೙ withparametersቐଵǡ ݂݅Ͳ ൑ ݃ ൑ ‫݌‬೙೙೙frequency( ݂ ൐ ݂ܿ )

is

given

by

ߪ଴ ൌ

ଵ

summarizedasߙ଴ ൌ ߨ݂௠ఘబ ௖௙Ǣ‫ݎ‬௙ ൌ  ௙ Ǣ ‫ ݌‬ൌ೎ඥሺ௛ିఒή௚ሻ ା௤Ͳǡ݂݅݂ ൑ ݂௖ ଶగଵ; ݄ൌమ ഏ
ǡ
ͳ൰
;
‫ݍ‬
ൌ
;
݃
ൌ
ቊ
; ߣ ൌ ݄Ȁ‫ ݌‬െ ͳ , and m is the
మ
ଶ௞௔బ
௞ ஺ೞ
ඥͳ െ ݂௖ Ȁ݂݂݅݂ ൒ ݂௖ 
ି఍మ 
యටమೖೌ

 ൬ߞଵ ටగబsurface density of the panel, ߩ଴ the ambient air density, c the sound speed traveling in the ambient
air, ߟ the total damping loss factor of the panel, wave number ݇ ൌ ʹߨ݂Ȁܿ, ‫ܣ‬௦ the area of the panel,஺ܽ଴ ൌ ೞ the dimension of the panel by considering it as an equivalent square panel; ݊ǡ ߞଵ ߞଶ are௔ା௕
empirical constants which are suggested to take the value of ݊ ൌ ʹǡ ߞଵ ൌ ͳǤ͵, and ߞଶ ൌ ͲǤͳʹͶ.
The total damping loss factor is the sum of the internal damping loss factor ߟ଴ and that due to thetransmission of vibrational energy from the panel to its surrounding elements ߟ௘ . According to Annex
C of ISO 12354-1:2017(E)(4), ߟ௘ can be evaluated for structural elements with a surface mass ݉ ൑ͺͲͲ݇݃Ȁ݉ଶ as ߟ௘ ൌா௧ యଵଶሺଵି௩ మ ሻ

௠
ସ଼ହඥ௙

. The critical frequency can be determined by ݂௖ୀ

௖మ
ଶగ

ெ

ට  , where ‫ ܤ‬ൌ஻is the bending stiffness of the panel.

From the sound transmission coefficient determined in Eq. (1), the sound transmission loss (STL)of a single homogeneous panel can be calculated by ൌ െͳͲሺ߬ሻ. To better match the predictionof STL with experimental results, it was proposed that the sound transmission coefficient below thecritical frequency ߬௟ᇱ is calculated as the sum of ߬௟ ܽ݊݀߬௛ in Eq. (1) by accounting for the bending
stiffness effect.
2.1.2 Modifications
Though it was identified that Davy’s model provides closest evaluations of STL for single glazing
panels in the current literature (5), the authors found that near the resonant and critical frequencies,
considerable discrepancies exist between the prediction of the STL by Davy’s model and the test
results, often there is about 2 - 3 dB discrepancy in terms of STC/OITC index. To address this issue,
certain revisions were made by the authors (5) by adding two more sections within the lower frequency
range and adjusting the radiation efficiency to improve the predictions based on Davy’s models.
Accordingly, the revised sound transmission coefficient of the panel is given byͳͳ ൅ ߙ଴ଶ
‫߬ۓ‬௟ଵ ൌ ଶ ݈݊ ቆቇ ǡ݂ ൑ ʹ݂௟ Ȁ͵ߙ଴ͳ ൅ ߙ଴ଶ ܿ‫ݏ݋‬௕ۖ߬ ൌ ߬௟ଶ ǡʹ݂௟ Ȁ͵ ൑ ݂ ൑ ݂௟‫ ߬ ۔‬ൌ ߬ ᇱ ǡ݂ ൑ ݂ ൑ ݂ 
௟
௟
௖
ۖ ௠
‫߬ ە‬௛ ǡ݂ ൐ ݂௖ 

(2)

1225

గ௖ ௧

ଵ ଶ

ଵ ଶ

ா

ಽ
൬ቀ௔ቁ ൅ ቀ௕ቁ ൰ is the resonance frequencies of the panel, ܿ௅ ൌ ටఘሺଵି௩మ ሻ thewhere ݂௟ ൌ ସξଷpropagation velocity of the quasi-longitudinal wave in the glazing panel;‫ܧ‬ǡ ߩǡ ߭ are Young’s modulus,
density and passion ratio of the panel, respectively, ܿ‫ݏ݋‬௕ ߠ is an associate parameter to consider thepractical limitation of sound radiation angle, which is given by (6) as ܿ‫ݏ݋‬௕ଶ ߠ ൌ ݉݅݊ ൬ଵ௞ඥ஺ೞǡ ͲǤͻ൰, ߬௟ଶ isdetermined by linear interpolation of ߬௟ଵ and ߬௠ . To better match the predictions with test results, theߪ ǡ݂ ൑ ͲǤͻ݂௖
original radiation efficiency ߪ଴ of single glazing is replaced by ߪଵ ൌ ൜ ଴, while݉݅݊ሺߪ଴ ǡ ߪ௖ ሻǡ ݂ ൒ ݂௖ 
between ͲǤͻ݂௖ ܽ݊݀݂௖ , it is obtained by linear interpolation, and ߪ௖ is a critical radiation efficiency tofilter out the unrealistic high value at critical frequency.
Figure 1 provides an overall comparison of the STL for a ½ inch monolithic glass panel (withdimension of 36 in by 84 in) among Viracon test result (7), simulation by INSUL 9.0 (8), original
prediction by (1), and the modified model (5). In comparison with measurements in the third-octave
band, the theoretical values were averaged over the three frequencies which were 2−1/9, 1, and 21/9
times the center frequency of the third-octave band if the critical frequency locates within themeasurement frequency (so does in the rest of the STL charts in this paper). Nearby the resonancefrequencies of the panel, it shows 3~4 dB difference of sound transmission loss between the originalmodel and the modified one.
Sound Transmission Loss(dB)

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50
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25
Freq. (Hz) 20

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80

100 125 160 200 250 315 400 500 630 800 1000 1250 1600 2000 2500 3150 4000 5000
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Insul

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Davy (1)

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Modified

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ViraconFigure 1 - STL of ½ inch monolithic glass panel (36 in by 84 in)
2.2 Laminated Glazing
Laminated glass has been gaining more applications in industry as it provides better performancefor structural, acoustical, and thermal performances. Laminated glass is achieved by bonding two or
more glass plies with thermoplastic polymeric interlayers. The resulting laminated glass performs
much safer than monothetic glass because the fragments remain attached to the interlayer even after
breakage. To apply the extended model for the monolithic glass given in the previous section tolaminated glasses, a laminated panel is considered as an equivalent single panel. The acoustic
performance of a single laminated glass depends not only on individual layers but also on theinterlayer and its dynamic performance. From this point of view, in addition to the effective propertiesof the laminated panel, the material properties of the interlayer must be included in the predicting
model.
The effective thickness of the laminated panel is determined by following the procedures in ASTM
E1300(9).
య݄௘௙ǡ௪ ൌ ට݄ଵଷ ൅ ݄ଶଷ ൅ ͳʹȞ‫ܫ‬௦

1226

(3)

where Γ is the shear transfer coefficient which is a measure of the transfer of shear stresses across the
ଵ
௛ೞ ௛భ
௛ ௛
ଶ
ଶ
ǡ ݄௦ଶ ൌ ௛ ೞା௛మ ǡ ݄௦ ൌ ͲǤͷሺ݄ଵ ൅ ݄ଶ ሻ ൅ ݄௙ , ݄௙ isinterlayerಶ಺ೞ ೓೏ , where ‫ܫ‬௦ ൌ ݄ଵ ݄௦ଶ ൅ ݄ଶ ݄௦ଵ , ݄௦ଵ ൌ
௛ ା௛
ଵାఞ

భ

మ
ಸ೓మ
ೞೌ

మ

భ

మ

the interlayer thickness (mm), E the Young’s modulus of glass, a the smallest in-plan dimension of
the laminated panel, and G the interlayer storage shear modulus, ߯ is a coefficient governed byboundary and loading conditions of the composite. For a laminated glass under the very particularcase of simply supported and uniformly distributed loading, a value of ߯ ൌ ͻǤ͸ was proposed by
Wölfel (10).
For a laminated glass with fixed thickens of individual layers, it can be found from Eq. (5) Thatthe effective thickness of the equivalent single glass keeps reducing as the thickness of the interlayer
increases, which makes sense from a structural point of view but does not when the sound transmission
is concerned. To better reflects the physics mentioned above, the equivalent thickness given in Eq. (5)is accordingly revised as݄௘௙ǡ௔௖ୀ ݄௘௙ǡ௪ ൅ ݄௙ Ȁ͵
Because of the existence of the viscoelastic polyme r layer, the radiance of sound transmitting
through the laminated glass varies accordingly, which varies a s the type of the interlayer varies.
Generally, the radiance decreases as the thickness of the polymer interlayer increases, more
specifically, its decaying rate is larger for softer interlayer compared with that of the stiffer one. To
reflect these trends, the radiance in laminated glass is proposed by introducing a decay factor ߰ fordthe ifferent interlayer, which is ߪ௖ᇱ ൌ ߪ௖ െ ߰‫ݐ‬௙ ǡwhere ߰ is determined by correlating the predictions
with series of test results on laminated glass panel of different interlayers.
Figure 2 provides a comparison of the STL of a ½ single laminated glass panel (consists of twoquarter inches monolithic glass combined with a 0.045 inch PVB thin layer, and dimension of 36 in
by 84 in) among Viracon test result (7), simulation by INSUL 9.0 (8), and the present model. The
comparison shows that the result predicted by Insul general overestimates the STL, especially at afrequency higher than the critical one, leading to an overestimated STC/OITC index. However, thepresent model can match the test result almost over the entire frequency range except those nearby
the resonant one where a spike exhibit, which might result from collected error because of practicaldifficulties or uncontrollable boundary effects during a test at a lower frequency.
60

Sound Transmission Loss(dB)

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25

Freq. (Hz) 20

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ViraconFigure 2 - STL of ½ inch single laminated glass panel (36 in by 84 in)

3. DOUBLE-LAYER GLAZING PANEL
3.1 Double-layer Monolithic Insulating Glazing
From Davy’s studies (2,6,11,12), the diffuse field sound transmission coefficient of a double
rectangular homogeneous panel with dimensions of ܽ ൈ ܾcan be summarized as

1227

ͳ
ͳ ൅ ߙௗଶ‫߬ ۓ‬௟ଵ ൌ ଶ ݈݊ ቆቇ ǡ݂ ൑ ʹ݂଴ Ȁ͵ߙௗͳ ൅ ߙௗଶ ܿ‫ݏ݋‬௕ଶ ߠۖۖ߬௟ଶ ǡʹ݂଴ Ȁ͵ ൑ ݂ ൑ ݂଴ ۖଶͳ െ ܿ‫ݏ݋‬௠ߠǡ݂଴ ൑ ݂ ൑ ݇଴ ݉݅݊൫݂௖ଵǡ ݂௖ଶ ൯߬ ൌ ߬௠ ൌ (4)ଶ ߠሻሺ‫ ݍ‬൅ ‫݌‬ሻሺ‫ ݍ‬൅ ‫ݏ݋ܿ݌‬௠‫۔‬ۖ߬௠௛ ǡ݇଴ ݉݅݊൫݂௖ଵ ǡ ݂௖ଶ ൯ ൑ ݂ ൑ ݉ܽ‫ݔ‬൫݂௖ଵ ǡ ݂௖ଶ ൯ۖߨ൫ඥ‫ݎ‬௙ଵ ൅ ඥ‫ݎ‬௙ଶ ൯ߤۖ߬ ൌǡ݂ ൐ ݉ܽ‫ݔ‬൫݂௖ଵ ǡ ݂௖ଶ ൯௛ଶ ଶͶߙଵ ߙଶ ߟଵ ߟଶߜௗଶ ሺߤଶ ൅ ‫ ݒ‬ଶ ሻ‫ە‬where ߬௟ଶ and ߬௠௛ are obtained from linear interpolations from their corresponding regions; ߙௗ ൌ௠ߙଵ ൅ ߙଶ with ߙ௜ ൌ ߨ݂ ೔ and ݉௜ is the surface density of the panel i, respectively; double panelఘ ௖బresonant frequency (also known as the mass-air-mass frequency) ݂଴ ൌ
ଵ కభ

௖
ଶగ

ఘ

ଵ

ට ௗబ ቀ௠ ା௠ ቁ with d of the
భ

మ

కమ

cavity gap between two panels,; ‫ ݍ‬ൌ ቀ ൅ ቁ ǡ ߦ௜ ൌ ߙ௜ ൫ͳ െ ‫ݎ‬௙௜ଶ ൯ǡ ‫ ݌‬ൌ ߦଵ ߦଶ ߜௗ , ݇଴ ൌ ͲǤͺ is a constant,ଶ కమకభsound absorption coefficient of the wall cavity of the double leaf wall ߜௗ ൌ ߜௗ ሺ‫ݐ‬௜ ǡ ݀ሻ is determinedଶ
by best matching a series of predictions and Viracon test results, ܿ‫ݏ݋‬௠ߠൌଵ௙݉݅݊ ቆͲǤͻǡ ݉ܽ‫ ݔ‬൬௞ඥ஺ ǡ ͲǤʹͶ൰ቇ; ‫ݎ‬௙௜ ൌ  ௙ , ߤ ൌ ߟଵ ඥ‫ݎ‬௙ଵ ൅ ߟଶ ඥ‫ݎ‬௙ଶ, and ‫ ݒ‬ൌ Ͷ൫ඥ‫ݎ‬௙ଵ െ ඥ‫ݎ‬௙ଶ ൯.
ೞ೎೔

To account for the stud born transmission effect between the two panels, the STL has been
accordingly revised as߬௅ଵ ൌ ߬௟ଵ ǡ݂ ൑ ʹ݂଴ Ȁ͵
‫ۓ‬ۖ ߬௅ଶ ൌ ߬௟ଶ ǡʹ݂଴ Ȁ͵ ൑ ݂ ൑ ݂଴ 
ۖۖ߬ெ ൌ  ߬௠ ൅ ߬ு ൅ ߬ௌ஽ ǡ݂଴ ൑ ݂ ൑ ݇଴ ݉݅݊൫݂௖ଵ ǡ ݂௖ଶ ൯߬ ൌ ߬ெு ൅ ൅߬ௌ஽ ǡ݇଴ ݉݅݊൫݂ ǡ ݂ ൯ ൑ ݂ ൑ ݉ܽ‫ݔ‬൫݂ ǡ ݂ ൯
௖ଵ ௖ଶ
௖ଵ ௖ଶ
‫۔‬
ଵ
݀‫ݔ‬
ۖ
‫׬‬଴ ଶଶଶଶۖۖ ߬ ൌ ሺ‫ݍ‬ଵ ൅ ሺ‫ ݔ‬െ ‫݌‬ଵ ሻ ሻሺ‫ݍ‬ଶ ൅ ሺ‫ ݔ‬െ ‫݌‬ଶ ሻ ሻ ൅ ߬ ǡ ݂ ൐ ݉ܽ‫ݔ‬൫݂ ǡ ݂ ൯
ு
ௌ஽
ଶ ଶ ଶ
௖ଵ ௖ଶ
ܵଵ ܵଶ ߜௗ‫ە‬where the stud born transmission efficiency ߬ௌ஽ ൌ݉݅݊ ൬ʹȀ ൬ͳ ൅ ቀͳ െସఠయȀమ ௠భ ௠మ ௖஼ಾீଶଷଶఘబమ ௖ య ஽௃మீ మ ௕బ ሺଶగ௙ሻమ

(5)

with stud transmission ratio ‫ܬ‬ଶ ൌቁ ൰ ǡ ‫ܭ‬൰, ‫ܥ‬ெ stud mechanical compliance, and K the minimum studtransmission; the space between studs is approximated as one third of the panel width, i.e., ܾ଴ ൌ ܾȀ͵ǡ‫ ܩ‬ൌ ݉ଵ ඥʹߨ݂௖ଵ ൅ ݉ଶ ඥʹߨ݂௖ଶ , ߬ெு is determined by linear interpolations from ߬ெ ܽ݊݀߬ு withoutഀ ആଵା ೔ ೔ߪߪ ݂ ൑ ͲǤͻ݂ܿଶఈ೔ ௥೑೔ଵ഑; ߪߪ௜ ൌconsidering ߬ௌ஽ ; ‫݌‬௜ ൌ ͳ െ ௥ , ‫ݍ‬௜ ൌ ௌ ೔ , ܵ௜ ൌ ఙ , ߪ௜ ൌ ൜ ௜
݉݅݊ሺߪ
೑೔
೔
೔
௖ ǡ ߪߪ௜ ሻ݂ ൒ ݂ܿଵǡ݂݅‫ ݌‬൑ ݃௜ ൑ ͳ೙ඥ௚ ೙ା௤೙ቐ ೔ ଵand critical radiation efficiency ߪ௖ is determined by the gap of the
ǡ
݂݅Ͳ
൑
݃
൑
‫݌‬
೙
௜
೙
೙
ሺ௛ିఒή௚ ሻඥ೔ା௤cavity between the two panels and their relative thickness as ߪ௖ ൌ ߪ௖ ሺ‫ݐ‬௜ ǡ ݀ሻ . Note that many
inconsistencies exist in determining the parameters values in Eqs. (4) and (5) among Davy’s studies on
double panels (2,6,11,12), some of them have been accordingly reunified and modified in this study
such that best agreement is achieved between the predictions and test results.
3.2 Double-layer Laminated Insulating Glazing
The STL of insulating-laminated (one layer monolithic and the other layer laminated) and double
laminated insulating (both layers are laminated) are developed based on section 3.1 . In this model,
the laminated layers are firstly treated as an equivalent single layer by following the approach insection 2.2, sound absorption coefficient and critical radiation efficiency are then determined byregression analysis and reconstructed as a function of the thickness of individual layers and the cavity
gap between them as ߜ௥ᇱ ൫‫ݐ‬௜ ǡ ‫ݐ‬௙ ǡ ݀൯ܽ݊݀ߪ௖ᇱ ൫‫ݐ‬௜ ǡ ‫ݐ‬௙ ǡ ݀൯, where ‫ݐ‬௜ is the equivalent thickens of laminatedlayers ሺ݅ ൌ ͳǡ ʹሻ and ‫ݐ‬௙ the thickness of the interlayer.

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65
Sound Transmission Loss(dB)

60
55
50
45
40
35
30
25

(a) Freq. (Hz)

20

50

63

80

100 125 160 200 250 315 400 500 630 800 1000 1250 1600 2000 2500 3150 4000 5000
29

24

30

29

32

37

40

40

41

42

44

45

44

45

48

53

57

59

Insul

32

31

31

30

29

26

27

31

36

39

42

44

46

48

50

51

49

51

55

59

63

Prediction

30

29

30

30

29

27

28

31

34

37

39

42

44

44

44

46

47

52

57

61

63

50

63

80

100 125 160 200 250 315 400 500 630 800 1000 1250 1600 2000 2500 3150 4000 5000
25

31

38

33

37

39

42

43

43

42

40

40

41

56

50

55

58

61

Insul

32

31

29

27

23

28

33

37

40

42

45

46

48

48

48

47

50

54

58

62

66

Prediction

32

31

31

30

27

30

32

35

37

40

43

45

46

45

41

43

48

52

56

60

63

Viracon70
Sound Transmission Loss(dB)

65
60
55
50
45
40
35
30
25

(b) Freq. (Hz)20

ViraconFigure 3 – STL of insulating-laminated double layer glass panel: (a) 1-3/16" overall - 1/4" glass, 1/2"
airspace, 3/16" glass, 0.060" PVB, 3/16" glass; and (b) 1-11/16" overall - 3/8" glass, 3/4" airspace,1/4"
glass, 0.060" PVB, 1/4" glass
Comparisons of the STL for two different insulating-laminated double layer glass panels among
Viracon test, Insul simulation results, and the present model are provided in Figure 3(a) and (b). The
overall thickness of these two panels are 1-3/16" and 1-11/16", respectively. The results show that ingeneral both the present model and Insul agree with the test results and they can provide similar dipsat the double panel resonant frequency and coincident frequency. However, nearby the coincide
frequency Insul predicts much higher STL than the test results while the present model well aligns
with the test result.
Figure 4 shows the comparisons of the STL for two different double layer laminated glass panels
among Viracon test, Insul simulation results, and the present model. At relatively low frequencies(below critical frequency of individual panels), the results predicted by Insul and the present model
fairly agree with the test results. At higher frequency (above coincidence frequency), the present
model still can reasonably match the test results. However, Insul significantly overestimates the STL,
with a discrepancy up to 8 dB for the STC index. The theoretical model behind Insul is not able toprovide a reliable prediction of STL for double layer laminated glass panels, especially when theoverall thickness of the double laminated glass panel is large.

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75
Sound Transmission Loss(dB)

70
65
60
55
50
45
40
35
30
25
(a) Freq. (Hz)

20

50

63

80

100 125 160 200 250 315 400 500 630 800 1000 1250 1600 2000 2500 3150 4000 5000
30

25

29

33

34

38

42

42

43

44

42

41

42

44

49

52

55

57

Insul

29

29

30

30

29

26

29

33

37

40

42

45

46

48

50

53

55

59

63

67

71

Prediction

31

30

30

31

29

27

29

32

35

38

40

43

44

44

45

47

50

54

58

61

64

50

63

80

100 125 160 200 250 315 400 500 630 800 1000 1250 1600 2000 2500 3150 4000 5000
29

32

37

37

37

40

42

38

39

41

44

47

50

53

55

57

59

60

Insul

35

30

25

29

34

38

41

43

46

48

49

51

51

53

57

61

65

69

73

77

81

Prediction

35

34

34

30

32

34

36

38

41

43

45

46

45

45

48

52

56

59

61

64

66

Viracon85
80
Sound Transmission Loss(dB)

75
70
65
60
55
50
45
40
35
30
25

(b) Freq. (Hz)20

ViraconFigure 4 – STL of double-laminated double layer glass panel: (a) 1-5/16" overall - 1/4" glass, 0.030" PVB,
1/4" glass, 1/2" airspace, 5/32" glass, 0.060" PVB, 5/32" glass, 3/16" glass; and (b) 2-5/8" overall - 3/8"
glass, 0.060" PVB, 3/8" glass, 1" airspace, 3/8" glass, 0.090" PVB, 3/8" glass

4. CONCLUSIONS
Based on existing theoretical models of sound transmission loss on single and multiple panels,
extended models have been developed for single and double insulating-laminated glass panels in thisstudy. Various comparisons among test results and simulation predictions by Insul are provided tovalidate the extended models.
For single laminated glass panel, the comparison shows that the result predicted by Insul general
overestimates the STL, especially at frequencies higher than the critical one, leading to an
overestimated STC/OITC index. For double laminated glass panels, comparison results show that thepredictions provided by Insul considerably overestimate the STL, with a discrepancy up to 8 dB interms of the STC index for relatively thicker double laminated glass panel, indicating that thetheoretical model behind Insul is not able to provide reliable prediction of STL for la minated glass
panels. In other words, Insul usually considerably overestimates the STL for high performance double

1230

laminated glass panels.
Well agreements among the predictions by the present models and test results for various single or
double laminated glass panels, however, demonstrate the viability of the present models. It is worthy
to note that the presented models were calibrated by comparing test results only from various glass
panels. The applicability of the presented models to other building materials such as gypsum board,
brick or masonry wall has not been investigated yet.

REFERENCES
1.

Davy JL. Predicting the sound insulation of single leaf walls: Extension of Cremer’s model. The Journalof the Acoustical Society of America. 2009 Oct 1;126(4):1871–7.

2.

Davy JL. The improvement of a simple theoretical model for the prediction of the sound insulation of
double leaf walls. The Journal of the Acoustical Society of America. 2010 Feb 1;127(2):841–9.

3.

Davy JL, Larner DJ, Wareing RR, Pearse JR. The acoustic radiation impedance of a rectangular panel.
Building and Environment. 2015 Oct 1;92:743–55.

4.

ISO 12354-1:2017(E). Building acoustics -- Estimation of the acoustic performance of buildings fromthe performance of elements -- Part 1: Airborne sound insulation between rooms.

5.

Huang Y, Chen F, DeGanyar T. Sound insulation of a single finite panel—Comparison, validation, andparametric studies. The Journal of the Acoustical Society of America. 2018 Sep 1;144(3).

6.

Davy JL. Predicting the Sound Insulation of Walls. Building Acoustics. 2009 Jan 1;16(1):1–20.

7.

Viracon Acoustic Performance Data Tables. Available from:http://www.viracon.com/pdf/ViraconAcousticPerfDataTables.pdf

8.

INSUL - Predicting Sound Insulation: A quick & accurate tool for predicting the sound insulation inwalls, floors, and ceilings.

9.

ASTM E1300-16. Standard Practice for Determining Load Resistance of Glass in Buildings. 2016.

10. Wölfel E. Nachgiebiger Verbund. Eine Näherungslösung und Deren Anwendungsmöglichkeiten.
STAHLBAU, DER. 1987;56(6).
11. Davy J. Predicting the sound transmission of double leaf cavity walls due to point and line connections.
Proceedings - European Conference on Noise Control. 2012 Jan 1;139–44.
12. Davy JL. Sound transmission of cavity walls due to structure-borne transmission via point and line
connections. The Journal of the Acoustical Society of America. 2012;132(2):814–21.

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