National Research Conseil national de

Council Canada recherches Canada

Institute for Institut de

Research in recherche en
Construction construction

Sound Transmission Loss

Measurements Through 190 mm and
140 mm blocks with Added Drywall and
Through Cavity Block Walls.
By A.C.C. Warnock

Internal Report No. 586

Date of Issue: January 1990

Canada
 2

Summary
This report presents the results of a series of sound transmission loss
measurements carried out under contract for the Ontario Concrete Block
Association.

The test series was augmented for research purposes by measuring sound
transmission losses at different stages in the construction and disassembly of the
walls. The report that follows provides an analysis of the information obtained
during the complete measurement series.

Résumé
Ce rapport présente les résultats d'une série de mesures de perte de
transmission sonore réalisées contrat pour le compte de l'Ontario Concrete Block
Association. Le CNRC a complété la série d'essais, à des fins de recherche, en
mesurant la perte de transmission sonore à différent stades de construction et de
démontage des murs. Ce rapport renferme une analyse de l'information obtenue
lors de la réalisation de toute la série de mesures.

The major findings of the study are as follows:

Concrete block walls are capable of providing high sound insulation at low
frequencies if layers of drywall are added to them in the correct fashion. Sound
transmission class ratings as high as 73 were obtained for a single wythe
190 mm block wall. To achieve such high values, appropriate drywall mounting
techniques and cavity depth must be selected. Sound absorbing material in
the cavity significantly increases sound insulation without changing wall
thickness.

A simple method of predicting sound transmission loss for certain block wall
systems was developed. This was used to predict sound transmission for
walls with concrete blocks of other common thicknesses.

In theory, two-leaf block walls have the potential to provide very high values of
sound transmission class and did so in the laboratory tests (STC 79 was
measured in one case). To achieve high performance in practical situations,
very careful design and construction are required.

Similar work needs to be done with lightweight, more porous blocks; there is
some evidence that more porous blocks increase effective cavity depths.
Thus, it might be possible to achieve high STC and good low-frequency
performance with lightweight blocks.

IRC IR-586 2
 Introduction
A knowledge of the factors that control sound transmission through block wall
systems is important for the economical control of noise in buildings. Noise sources
in neighboring homes include stereos, voices and television. Mechanical equipment
next to living areas is also a frequent source of complaint and needs to be
controlled.

Despite the fact that block and other types of walls have been in use for many years,
there was a need for new measurements on block walls. There were several
reasons for this.

There are discrepancies among the data presented in the literature for nominally
identical blocks with and without finished surfaces. Some of these can be
ascribed to improvements in measurement techniques that render old data
obsolete, some to differences in installation details and laboratory facilities, and
some to other unidentified physical factors.

Sound insulation requirements in the 1990 National Building Code of Canada are
to be increased relative to earlier versions and there is a general demand for
greater sound insulation in homes. Some jurisdictions in Canada are asking for
sound transmission class ratings of 55 or better. Not enough information is
available to allow the economical selection of block walls with high values of
sound attenuation.

There is increasing recognition that low frequency sound, below the limit normally
measured in tests, is the major cause of complaint in buildings. Only a few
laboratories have begun to collect sound transmission information at low
frequencies, because not all have the required laboratory facilities to collect
reliable data.

There is a lack of information on block wall systems with very high STC ratings.
This is despite the fact that it is relatively simple to get such ratings and that block
walls are often the system of choice for reducing high levels of noise from
machine rooms.

For these reasons, the series of measurements that are described in what follows
was undertaken.

IRC IR-586 3
The major part of the work was a series of measurements to study the influence on
the sound transmission loss of different methods of attaching single layers of drywall
to blocks. A short test series was run on 75% and 100% solid, 140 mm concrete
blocks. As well, measurements were made on cavity block walls to determine the
effects of different thermal insulation in the cavity and to determine the importance of
flanking sound transmission through the laboratory test frame.

The transmission losses for all constructions together with information on the
materials and construction techniques used can be found in the Appendices.

IRC IR-586 4
 Block walls with no surface finish
The major factor controlling the sound transmission through a single wythe wall is
the weight per unit area. The stiffness and thickness of the wythe, however, are also
important. Simple theory predicts that sound transmission loss, and therefore the
STC, will increase by about 5 decibels each time the weight of the wall is doubled.

Figure 1 shows measured sound transmission class (STC) ratings for single wythe
block walls from a number of sources in the literature.

65

60

55
STC

50

45

STC = 0.5 x Block Weight + 39

40

35
5 10 15 20 25 30 35 40
Block weight, kg

Figure 1: Relationship between sound transmission class and the weight of

the blocks used to construct a single layer wall.
Previous work has shown that where the block is porous, sealing the surface can
have a significant effect on the sound transmission: the more porous the block, the
greater the increase in sound transmission loss. The air flow resistance of a
material, related to the porosity, can be measured relatively easily; unfortunately, it is
not customary to measure this quantity when sound transmission for block walls is
being evaluated.

The walls selected for Fig. 1 were thought to have little or no sound leaking through
the pores of the blocks. Nevertheless, the scatter in the diagram is still large and
there may be some points representing leaky structures. The STC is plotted against
the block weight. Simple theory suggests that the logarithm is a more appropriate
variable. Regression analysis of this data set shows, however, that the goodness of
fit is about the same. Block weight is usually more readily available, so the plot is
presented as shown. It is clear that the surface mass is not a good enough predictor.

IRC IR-586 5
The combination of the effects of weight, stiffness, porosity, and the shape of normal
hollow block is too complicated to allow simple theoretical prediction of sound
transmission loss. One has to fall back on empirical approaches and measurement.

190 mm blocks with attached drywall

The goal of this part of the work was to study the effects of different methods of
attaching drywall to a 190 mm block wall. Figure 2 shows schematically the methods
that were used. These included some common techniques (resilient channels, wood
furring, 65 mm steel studs) and alternatives that are not in common use (50 and
75 mm Z-bars). For each method of attachment, the wall was tested with the cavity
empty and with it filled with sound-absorbing material. The range of cavity depths
was chosen to cover all likely practical cases. In this figure and in the tables that
follow, a coded method of describing wall constructions is used. The coding is
explained in Appendix A2.

40 mm wood strapping

13 mm resilient channels

50 and 75 mm Z-bars

65 mm steel studs

Figure 2: Techniques used to attach drywall to the block walls. In each case
the walls were tested with and without glass fibre in the cavity.

IRC IR-586 6
Mass-air-mass resonance
The addition of layers of drywall to the surfaces of a block wall creates a cavity
behind the drywall. Theory predicts that walls with unfilled cavities will resonate at a
frequency that is determined by

60
f mam =
md

where m is the mass per unit area of the drywall, kg/m2, and d is the distance from
the drywall to the block surface, m.

The mass per unit area of the block, because it is so much greater than that of the
drywall, does not affect the location of the resonance frequency.

Near this resonance, sound transmission losses are reduced below those for the
unfinished wall. The mass-air-mass resonance frequency usually occurs at low
frequencies and is often the reason for a reduction in the STC when extra layers of
drywall are added to the block wall. The greater the depth of the cavity, the lower the
frequency at which the resonance occurs. Alternatively, increasing the weight of the
drywall layer also lowers the resonance frequency. Lowering the mass-air-mass
resonance frequency usually increases STC. The frequency and the depth of the
resonance are important pieces of information for designing block walls.

Effect of sound absorbing material on mass-air-mass resonance

Adding sound absorbing material to the cavity behind the drywall lowers the
resonance frequency. The behavior of the air in the cavity changes from adiabatic to
isothermal and the position of the mass-air-mass resonance is now given by

43
f mam =
md

Sound absorbing material will also damp resonances in the cavity and reduce their
effect. This applies to the mass-air-mass resonance and other cavity resonances
that occur at higher frequencies. Since the mass-air-mass resonance occurs at low
frequencies, however, where sound absorbing materials are less effective, the
damping effect of absorbers at low frequencies may be slight if the cavity is not
deep.

Figure 3 gives some results for walls with unfilled cavities. Increasing cavity depth
clearly leads to a shift in the mass-air-mass resonance to lower frequencies as
predicted. It is also clear that the mass-air-mass resonance can seriously reduce the
sound transmission loss of the wall at the important low frequencies, even if this
does not always result in a lower STC.

IRC IR-586 7
 80 80

70 70
40 mm wood strapping
Transmission Loss, dB

Transmission Loss, dB
60 60
13 mm resilient metal furring

50 50

40 40

TL-87-356 STC 50 TL-87-356 STC 50

30 TL-87-362 STC 53 30 TL-88-368 STC 51

20 20
63 125 250 500 1k 2k 4k 63 125 250 500 1k 2k 4k
Frequency, Hz Frequency, Hz

80 80

70 70

50 mm metal Z-bars
Transmission Loss, dB

Transmission Loss, dB
60 60 75 mm metal Z-bars

50 50

40 40

TL-87-356 STC 50 TL-87-356 STC 50

30 TL-88-387 STC 52 30 TL-87-418 STC 57

20 20
63 125 250 500 1k 2k 4k 63 125 250 500 1k 2k 4k
Frequency, Hz Frequency, Hz

Figure 3: Transmission loss measurements for wall with drywall attached on

one side only. There is no sound-absorbing material in the cavity. The gray
curve in each case is the result for the bare 190 mm blocks.

Figure 4 shows results for walls with the same drywall mounting method used and
the cavity filled and unfilled with absorptive material. As expected, the mass-air-
mass resonance moves to a lower frequency and the transmission loss curve
appears to move sideways to lower frequencies. The result is improved STC ratings
and improved sound transmission loss at low frequencies.

IRC IR-586 8
 80 80

70 70
13 mm resilient metal furring
40 mm wood strapping

Transmission Loss, dB
Transmission Loss, dB

60 60

50 50

40 40

TL-87-356 STC 50 TL-87-356 STC 50

30 TL-87-362 STC 53 30 TL-88-368 STC 51
TL-88-357 STC 55 TL-88-371 STC 54

20 20
63 125 250 500 1k 2k 4k 63 125 250 500 1k 2k 4k
Frequency, Hz Frequency, Hz

80 80

70 70

50 mm metal Z-bars
75 mm metal Z-bars
Transmission Loss, dB

Transmission Loss, dB
60 60

50 50

40 40

TL-87-356 STC 50 TL-87-356 STC 50

30 TL-88-387 STC 52 30 TL-87-418 STC 57
TL-88-381 STC 59 TL-88-421 STC 61

20 20
63 125 250 500 1k 2k 4k 63 125 250 500 1k 2k 4k
Frequency, Hz Frequency, Hz

Figure 4: Transmission loss measurements for walls with drywall attached

on one side only. The open circles are for the cavity unfilled, the closed
circles are for the cavity filled with sound-absorbing material. The gray curve
in each case is the result for the bare 190 mm blocks.

Prediction of sound transmission through block walls with attached drywall.

While no comprehensive theory exists to predict the sound transmission through
block walls, some simple models suggest that the effects of additional layers can be
found by simply adding terms to the sound transmission loss values for the bare
wall. For example, each time a layer of drywall supported on resilient channels is
added to a bare block wall surface, it will have the same relative effect no matter
what is on the other side of the wall.

To illustrate the idea, Fig. 5 shows results for walls with one side and two sides
treated. The addition of the second layer further improves transmission loss at
higher frequencies and further reduces it at lower frequencies. The supposition is
that, on average, the change from the bare wall to one side treated is the same as
the change from one side treated to both sides treated.

IRC IR-586 9
In the sections that follow, this approach to prediction is described and the results of
the prediction are presented.

80 80

70 70

40 mm wood strapping
Transmission Loss, dB

Transmission Loss, dB
60 60

50 50

40 40

TL-87-356 STC 50 TL-87-356 STC 50

30 TL-87-362 STC 53 30 TL-88-368 STC 51
TL-88-361 STC 54 TL-88-374 STC 49

20 20
63 125 250 500 1k 2k 4k 63 125 250 500 1k 2k 4k
Frequency, Hz Frequency, Hz

80 80

50 mm metal Z-bars with

70 70
glass fibre in cavity
50 mm metal Z-bars
Transmission Loss, dB

Transmission Loss, dB
60 60

50 50

40 40

TL-87-356 STC 50 TL-87-356 STC 50

30 TL-88-387 STC 52 30 TL-88-381 STC 59
TL-87-386 STC 52 TL-88-384 STC 64

20 20
63 125 250 500 1k 2k 4k 63 125 250 500 1k 2k 4k
Frequency, Hz Frequency, Hz

Figure 5: Transmission loss measurements for walls with drywall attached

on one side (open circles) and on both sides (closed circles). The gray curve
in each case is the result for the bare 190 mm blocks.

Derivation of difference TL curves

Table 1 shows the measured STC values for all the 190 mm block walls that were
tested. Walls in the first column had only one side finished. Walls on the diagonal
had both sides finished in the same way. Other walls had mixed finishes that can be
identified from the row and column headings in the table.

IRC IR-586 10
 Table 1: Measured STC ratings for 190 mm block wall systems tested.
Letter codes identify methods of attaching 16 mm drywall.
Bare A B C D E F G H I
Bare 50
A Direct 50 49
B WS38 53 54
C WS38_GFB38 55 57 58 59
D RC13 51 58 49
E RC13_GFB19 54 52 49
F ZC50 52 52 52
G ZC50_GFB50 59 59 59 64
H SS65 58 57
I SS65_GFB65 60 61 65 72
J ZC75 57 57 59 68
K ZC75_GFB75 61 62 66 73

To calculate the difference in transmission loss due to a particular surface treatment,

the sound transmission loss values for the bare block were subtracted from the
sound transmission loss values for the walls in the first column. The bare block
results were also subtracted from the diagonal entries and the result divided by two.
Other combinations were found in the table to get the difference-TL curve for each
surface treatment. The results for each surface finish were averaged.

Figure 6 gives examples of the difference curves for four of the drywall mounting
methods tested. Table 2 lists the difference TL values for all cases.

Prediction of STC
The difference spectra listed in Table 2 were used to predict the measured sound
transmission losses and STC for each mounting method shown in Fig. 2. The
appropriate difference contours were added to the TL result for the bare block in
each case. Figure 7 compares the predicted and measured STC ratings for all
measured 190 mm walls. The agreement is very good; of the 31 predictions, 15
agreed exactly with measurement, 11 were wrong by 1 point and 5 were wrong by 2
points.

IRC IR-586 11
 20 20

15 15
Change in Transmission Loss, dB

Change in Transmission Loss, dB

10 10

5 5

0 0

RC13
-5 WS38 -5 RC13_GFB19
WS38_GFB38

-10 -10
63 125 250 500 1k 2k 4k 63 125 250 500 1k 2k 4k
Frequency, Hz Frequency, Hz

20 20

15 15
Change in Transmission Loss, dB

Change in Transmission Loss, dB

10 10

5 5

0 0

-5 ZC50 -5 ZC75
ZC50_GFB50 ZC75_GFB75

-10 -10
63 125 250 500 1k 2k 4k 63 125 250 500 1k 2k 4k
Frequency, Hz Frequency, Hz

Figure 6: Average difference in transmission loss between the bare wall and
the wall with different surface finishes on one side only. The open circles are
for the cavity unfilled, the closed circles are for the cavity filled with sound-
absorbing material.

Prediction of TL curve
While the agreement between measured and predicted STC ratings is satisfactory,
the agreement between measured and predicted transmission loss values is also
important. If the important low frequency values are not properly predicted, this
method has no value.

Figure 8 shows examples of the agreement between the measured and predicted
transmission loss curves. For practical estimates, the agreement is quite
satisfactory.

IRC IR-586 12
 75

70

65

Measured STC
60

55

50

45
45 50 55 60 65 70 75
Predicted STC

Figure 7: Comparison of the measured sound transmission class rating with

that calculated using the addition method described in the text. The straight
line shows where the two values are equal.
80 80

70 70
Transmission Loss, dB

Transmission Loss, dB

60 60

50 50

40 40

40 mm wood strapping, glass

40 mm wood strapping and
30 fibre and drywall on both 30 drywall on both sides, STC 54
sides, STC 59

20 20
63 125 250 500 1k 2k 4k 63 125 250 500 1k 2k 4k
Frequency, Hz Frequency, Hz

80 80

70 70
Transmission Loss, dB

Transmission Loss, dB

60 60

50 50

40 40

13 mm resilient channels and drywall on

one side, channels, glass fibre and 50 mm Z-bars, glass fiber and
30 30 drywall on both sides, STC64
drywall on the other side, STC 52

20 20
63 125 250 500 1k 2k 4k 63 125 250 500 1k 2k 4k
Frequency, Hz Frequency, Hz

Figure 8: Comparison of predicted (o) and measured transmission loss

(solid line) for 190 mm block walls.

IRC IR-586 13
Application of prediction scheme to other blocks
While this is not a rigorous prediction scheme, it has benefits of which can now be
discussed.

Because the position of the mass-air-mass resonance is not affected by the block
weight, the difference-TL curve for each drywall mounting method should be the
same for any normal hollow block of whatever thickness. An important assumption
here is that the porosity of the block is about the same in each case. If this is the
case, then the difference-TL curves can be added to the measured sound
transmission loss curve for other normal-weight bare blocks and sound transmission
loss values predicted for all the mounting methods used in this study. The
measurements on 140 mm blocks described below provided an opportunity to test
this hypothesis.

140 mm blocks with added drywall

Two types of 140 mm block were measured, a 75% solid block and a 100% solid
block. The configurations tested gave an opportunity to test the validity of the
prediction scheme described above. As with the 190 mm blocks, there were no
significant changes to the TL values after the blocks were painted. Figure 9 shows
the measured and predicted TL values for the four configurations. The predicted
STC in each case is 1 point lower than that measured, which is acceptable
agreement. In cases b, c, and d, 13 mm drywall was used in the construction instead
of 16 mm drywall. The ratings are determined by the TL values from about 200 to
800 hertz and, it is clear from the figure that the predicted values are slightly too low
in this region and markedly lower at higher frequencies. Nevertheless, the overall
agreement is fairly good, especially in the important low-frequency range.

Predicted STC ratings for 90, 140, 190, 240, and 290 mm normal weight blocks are
given in Tables 3 to 9.

Conclusions for attached drywall series.

The correct choice of cavity depth and the addition of sound absorbing material
ensures that sound transmission loss values are not degraded in the frequency
range that is important to the end user. Conversely, a wrong choice results in a
reduction in performance despite the addition of the extra material to the basic block
wall.

Further work is need to examine the differences between lightweight and normal
weight blocks. There is some evidence in the literature that block porosity increases
the effective cavity depth. This raises the possibility that lightweight block systems
might perform as well as normal weight block systems. Measurements in the
literature from other laboratories do not extend to low frequencies, so the differences

IRC IR-586 14
between the block types can not be evaluated without further extended
measurements of the type described here.

90 90

75% solid, 65 mm steel studs, 65 mm glass fibre

80 and 16 mm drywall on one side; 40 mm wood strapping,
80 75% solid, 65 mm steel studs, 65 mm glass fibre 38 mm glass fibre, and 13 mm drywall on the
and 16 mm drywall on one side, STC 61 second side, STC 67
70
Transmission Loss, dB

Transmission Loss, dB
70

60
60
50

50
40

40
30

30 20
63 125 250 500 1k 2k 4k 63 125 250 500 1k 2k 4k
Frequency, Hz Frequency, Hz

80 80

70 75% solid, 40 mm wood strapping, 100% solid, 40 mm wood strapping,

70
38 mm glass fibre, and 13 mm drywall on one 38 mm glass fibre, and 13 mm drywall on one
side, STC 55 side, STC 58
Transmission Loss, dB

Transmission Loss, dB

60 60

50 50

40 40

30 30

20 20
63 125 250 500 1k 2k 4k 63 125 250 500 1k 2k 4k
Frequency, Hz Frequency, Hz

Figure 9: Comparison of predicted (o) and measured transmission loss

(solid line) for 140 mm block walls.

Cavity block walls

A cavity block wall with no connections between the wythes should have sound
transmission loss values much greater than a single wythe wall of the same total
weight. Both layers are heavy, so the mass-air-mass resonance should occur at very
low frequencies and there should be no reduction in sound transmission loss in the
frequency range normally used for measurement. Against this, one must weigh the
practical difficulties associated with constructing two block wythes that are not
connected. In practice, there is always some transmission of energy around the
periphery of the walls and through other parts of the structure. It requires careful
design to reduce this flanking transmission; it can not be eliminated in practical
cases. Where wire ties are used to bind the two wythes of the wall together, clearly
there will be a significant reduction in performance because of transmission through
the ties.

IRC IR-586 15
Measurements in the laboratory provide an opportunity to look at the effects of
flanking transmission, at least in a qualitative way.

Room/test frame mounting results - 190/90 mm blocks

Figure 10 gives a cross section of the wall test opening in the laboratory. Normally,
test specimens are mounted on the test frame and do not rigidly contact the rooms
on either side. During this series, a split rib block wall was constructed on the
receiving room lip as shown in the figure. Since both reverberation rooms are
mounted on steel springs, this mounting technique provides the least amount of
flanking transmission that can be achieved in the laboratory and is far better than
could be achieved in normal field installations.

TEST
FRAME
300mm
CONCRETE

RECEIVING SOURCE
ROOM ROOM

CAVITY
BLOCK
WALL

Figure 10: Cross section of the 2.4 x 3.05 m wall test opening at the National
Research Council. The rooms are constructed of 300 mm concrete and
supported on steel springs. Walls for testing are usually mounted on the
wheeled test frame, which is not in solid contact with the structure of the
source or receiving rooms. In this case, one wythe of the cavity block wall
was mounted on the frame, the other was mounted in the receiving room
opening.
An additional advantage of the mounting technique shown in Fig. 10 is that, since
the test frame is on wheels, it allows simple changes of the sound absorbing
materials in the cavity.

IRC IR-586 16
Figures 11a and 11b show the results for this mounting. As expected, the STC rating
is high in each case and there is no sign of reduction in transmission loss at the
lower frequencies relative to the single wythe 190 mm or 90 mm block wall. It is
interesting to see that, even in a heavy construction like this, there is still something
to be gained by using effective sound absorbers in the cavity; styrofoam does not
absorb sound well.
90 90
190/90 mm cavity wall. 155 mm 190/90 mm cavity wall. 155 mm
deep cavity containing 65 mm deep cavity containing 50 mm
80 glass fibre insulation. STC 79 80 SM styrofoam wall insulation.
STC 67
Transmission Loss, dB

Transmission Loss, dB
70 70

60 60

50 50

190 mm bare blocks, STC 50

190 mm bare blocks, STC 50
40 40

30 30
63 125 250 500 1k 2k 4k 63 125 250 500 1k 2k 4k
Frequency, Hz Frequency, Hz

90 90
90/90 mm cavity wall. 115 mm 90/90 mm cavity wall. 115 mm
deep cavity containing 65 mm deep cavity containing 50 mm
80 of glass fibre wall insulation. 80 of SM styrofoam wall
STC 77 insulation. STC 69

70 70
Transmission Loss, dB

Transmission Loss, dB

60 60

50 50

40 40
90 mm bare blocks, STC 44
90 mm bare blocks, STC 44

30 30

20 20
63 125 250 500 1k 2k 4k 63 125 250 500 1k 2k 4k
Frequency, Hz Frequency, Hz

Figure 11: Sound transmission loss curves for cavity block walls mounted as
shown in Figure 10. Results for single wythe block walls are shown in each
graph.

Room/test frame mounting results - 90/90 mm blocks

The 190 mm block wall on the test frame was demolished and replaced with a
90 mm block wall. This allowed a further set of measurements to be made with the
same set of materials in the cavity. The results are shown in Fig. 11c and 11d.
Reductions in sound transmission loss due to the use of the lighter 90 mm block are
slight.

Test frame only mounting - 90/90 mm blocks

The 90 mm split rib block was demolished and a nominally identical wall constructed
on the frame as shown in Figure 12. In this configuration, there will be transmission

IRC IR-586 17
of acoustical energy through the structure of the frame. This flanking transmission
will be reduced to some extent because of the construction of the frame liner which
is shown in the expanded section of Figure 12.

The measured sound transmission loss for this configuration is shown in Figure 13.
There is a substantial decrease in performance relative to the case where the blocks
are isolated.

TEST
FRAME

300 mm
CONCRETE

RECEIVING CAVITY SOURCE

ROOM BLOCK ROOM
WALL

SPLIT
MOUNTING
SURFACE

INTERNAL
RUBBER
FRAME
LINING

Figure 12: Cavity wall with both 90 mm wythes constructed on the test
frame. Some flanking through the wood liner of the test frame is possible,
although the rubber inserts will reduce this to some extent.

IRC IR-586 18
 90

80

Transmission Loss, dB
70

60

50 Both wythes on same frame. 90 mm deep

cavity containing 65 mm of glass fibre wall
insulation. STC 62

40 Independent wythes. 115 mm deep cavity

containing 65 mm of glass fibre wall
insulation. STC 77.

30
63 125 250 500 1k 2k 4k
Frequency, Hz

Figure 13: Transmission loss measurement for 90/90 mm cavity wall with
both wythes mounted on the test frame. A result from Figure 11 is shown for
comparison.

Conclusions for cavity walls

The basic principles governing the sound transmission loss through cavity walls still
apply to cavity block walls. The measurements reported here make it clear that it is
extremely difficult to give a definitive rating to the sound transmission loss for such
walls. Even in the laboratory, where construction is carefully controlled, it is possible
to get widely differing answers. The lesson to be drawn from this is that to merely
approach the potential of a cavity wall requires extremely careful design to reduce
flanking transmission and close supervision of construction to ensure that no errors
are made.

Overall conclusions
The issue of block porosity and its effect on sound transmission loss of composite
walls needs to be studied further. Measurements over the same frequency range
need to be carried out in a similar systematic fashion using lightweight, more porous
blocks.

To validate the prediction scheme presented here, it is desirable that measurements

be made using more than one type of block. The number of systems measured
could be reduced because of the knowledge gained from the present series.

The cavity walls tested here were not linked together with wire ties. It would be
useful to establish through measurement what effect ties have and perhaps find a tie
design that has minimum acoustical influence.

IRC IR-586 19
In future measurements on block walls, the air flow resistivity should be measured
and presented as part of the sound transmission loss report

IRC IR-586 20
Table 2: Mean differences in transmission loss relative to the bare 190 mm block wall.

Frequency, hertz
63 80 100 125 160 200 250 315 400 500 630 800 1000 1250 1600 2000 2500 3150 4000 5000 6300
WS38 Mean -1.3 -4.4 -7.4 -1.7 -1.1 3.1 3.1 1.2 4.7 5.0 6.4 6.5 5.6 5.4 4.5 3.3 0.0 0.4 1.1 2.5 4.3
WS38 SD 1.0 0.9 0.4 0.6 0.9 1.2 1.1 1.0 0.5 0.2 0.3 0.2 0.5 0.5 0.4 0.9 0.6 0.5 0.4 0.5 0.3
WS38_GFB38 Mean -3.4 -5.3 -5.5 2.3 5.7 9.7 8.5 5.7 7.8 6.3 5.9 5.9 5.7 6.4 6.0 3.5 0.1 1.1 2.2 3.5 4.7
WS38_GFB38 SD 0.8 0.8 1.7 1.0 1.3 1.2 1.7 2.0 1.7 1.0 0.5 0.8 0.9 1.4 1.9 1.3 0.9 1.1 1.4 0.9 1.2
RC13 Mean -0.2 -0.3 -2.3 -1.6 -3.6 -4.0 -3.6 -0.2 4.5 6.6 6.2 6.8 5.8 6.2 5.7 4.6 3.9 3.4 3.4 3.9 3.4
RC13 SD 0.2 0.7 0.2 0.4 0.1 0.2 0.1 0.6 0.6 0.8 1.6 2.3 3.1 3.2 2.8 2.3 1.8 2.0 1.6 0.9 0.8
RC13_GFB19 Mean -2.3 -3.6 -5.8 -3.5 -1.1 2.5 5.8 7.6 9.0 8.9 7.8 8.0 7.8 7.7 6.5 5.1 5.2 4.7 4.7 4.7 3.6
RC13_GFB19 SD 1.4 0.5 1.4 1.4 1.3 0.7 0.4 0.8 1.7 2.6 2.9 3.2 3.7 3.6 3.4 2.8 2.6 2.8 2.1 2.1 2.4
ZC50 Mean -3.7 -5.1 -6.8 -3.3 -1.9 -1.0 1.6 4.1 7.6 9.3 9.2 9.6 10.0 9.9 8.6 6.6 4.3 3.4 3.8 4.2 2.7
ZC50 SD 0.4 0.6 2.7 1.3 1.8 1.5 3.0 1.4 0.6 0.7 1.0 1.5 1.8 0.8 0.8 1.1 0.5 0.9 1.3 1.4 1.4
ZC50_GFB50 Mean -5.1 -5.5 -2.3 4.2 5.5 7.7 8.4 10.2 12.5 12.2 11.9 11.7 10.3 9.5 6.5 5.1 4.5 4.2 4.6 4.5 2.5
ZC50_GFB50 SD 1.1 0.4 2.7 0.5 1.7 1.4 3.2 2.1 1.9 2.2 2.7 3.0 3.4 3.2 3.1 2.3 1.6 1.7 1.9 2.1 2.5
SS65 Mean -4.7 -3.8 -3.0 1.0 2.5 6.4 8.8 10.0 14.6 16.6 15.5 15.1 13.3 10.7 8.6 7.7 7.0 7.3 7.6 7.1 4.2
SS65 SD 1.6 1.1 2.2 0.9 2.1 1.7 2.9 2.6 1.1 1.3 1.1 1.5 1.9 2.2 1.3 0.7 0.5 0.6 1.1 2.1 2.5
SS65_GFB65 Mean -4.0 -0.8 2.5 7.1 8.3 11.8 13.7 14.3 15.4 14.8 13.9 13.1 11.0 9.0 8.2 7.8 7.7 9.0 8.4 7.2 4.7
SS65_GFB65 SD 1.2 0.5 2.8 2.0 2.7 2.8 3.4 2.4 1.8 2.5 2.8 2.9 3.2 2.3 1.1 1.0 1.4 1.0 1.6 1.8 2.2
ZC75 Mean -5.7 -6.2 -1.6 1.9 3.8 4.4 7.8 10.5 12.9 14.2 14.4 13.3 11.5 10.9 10.0 6.3 3.7 4.4 6.6 6.3 5.5
ZC75 SD 0.7 0.3 3.5 2.2 2.9 2.9 4.3 3.1 1.6 2.3 2.8 2.7 2.5 0.4 0.9 0.3 1.0 0.8 1.0 0.6 1.4
ZC75_GFB75 Mean -5.2 -2.1 4.2 8.1 10.6 12.3 12.9 12.5 16.0 16.1 15.1 13.4 11.2 10.3 10.0 8.4 5.3 6.2 7.4 6.1 4.2
ZC75_GFB75 SD 1.7 1.3 3.0 1.8 2.9 3.0 3.3 2.2 1.5 2.7 3.0 3.1 3.1 1.9 1.6 1.2 1.4 1.1 1.8 2.1 2.9

21
Table 3: STC ratings predicted for block walls using TL-88-447, 90 mm normal
weight blocks. Table headings are methods of attaching 16 mm drywall
Bare B C D E F G H I J K
Bare 44
B WS38 48 50
C WS38_GFB38 50 53 54
D RC13 47 49 53 45
E RC13_GFB19 50 51 55 49 49
F ZC50 50 50 55 48 49 49
G ZC50_GFB50 53 56 58 55 57 57 60
H SS65 54 55 59 52 53 54 61 58
I SS65_GFB65 56 58 60 58 59 60 63 64 65
J ZC75 54 55 58 53 54 54 60 59 63 59
K ZC75_GFB75 56 58 60 58 61 60 63 64 65 63 65

Table 4: STC ratings predicted for block walls using BRN217-6NA, 140 mm
blocks. Table headings are methods of attaching 16 mm drywall
Bare B C D E F G H I J K
Bare 45
B WS38 48 49
C WS38_GFB38 52 54 56
D RC13 46 47 53 42
E RC13_GFB19 50 49 53 47 47
F ZC50 49 49 53 45 47 47
G ZC50_GFB50 54 56 60 53 55 55 62
H SS65 54 53 57 50 52 52 59 56
I SS65_GFB65 57 59 63 56 58 58 65 62 68
J ZC75 54 54 58 50 52 53 60 57 63 58
K ZC75_GFB75 58 60 63 58 59 59 65 63 68 64 68

Table 5: STC ratings predicted for block walls using TL88-473, 75% solid,
140 mm blocks. Table headings are methods of attaching 16 mm drywall
Bare B C D E F G H I J K
Bare 47
B WS38 51 53
C WS38_GFB38 54 57 60
D RC13 46 49 54 42
E RC13_GFB19 53 56 60 52 54
F ZC50 51 53 58 47 54 52
G ZC50_GFB50 58 60 64 54 61 59 66
H SS65 58 59 64 55 58 58 66 63
I SS65_GFB65 60 64 66 60 64 64 69 69 72
J ZC75 57 59 63 54 59 57 65 64 69 62
K ZC75_GFB75 61 64 66 59 65 64 69 69 72 69 72

IRC IR-586 22
Table 6: STC ratings predicted for block walls using TL88-487, 100% solid
140 mm blocks. Table headings are methods of attaching 16 mm drywall
Bare B C D E F G H I J K
Bare 50
B WS38 53 55
C WS38_GFB38 57 60 63
D RC13 48 51 57 44
E RC13_GFB19 55 55 61 52 55
F ZC50 52 54 60 48 54 51
G ZC50_GFB50 60 62 66 56 62 60 68
H SS65 59 59 65 56 59 58 65 62
I SS65_GFB65 63 64 69 61 64 64 71 68 74
J ZC75 58 60 65 54 60 57 65 64 69 62
K ZC75_GFB75 63 66 69 61 67 65 71 70 74 70 74

Table 7: STC ratings predicted for block walls using TL-88-356 190 mm blocks.
Table headings are methods of attaching 16 mm drywall.
Bare B C D E F G H I J K
Bare 50
B WS38 53 54
C WS38_GFB38 55 58 60
D RC13 51 53 58 49
E RC13_GFB19 53 52 56 52 50
F ZC50 54 52 56 52 50 50
G ZC50_GFB50 59 59 63 60 58 58 65
H SS65 58 56 60 56 55 55 62 59
I SS65_GFB65 61 62 66 63 61 61 68 65 71
J ZC75 59 57 61 57 55 56 63 60 66 61
K ZC75_GFB75 62 63 67 64 62 62 69 66 72 67 72

Table 8: STC ratings predicted for blocks walls using BRN217-10NA 240 mm
normal weight blocks. Table headings are methods of attaching 16 mm drywall
Bare B C D E F G H I J K
Bare 48
B WS38 50 50
C WS38_GFB38 54 57 59
D RC13 48 48 54 44
E RC13_GFB19 51 50 55 48 49
F ZC50 50 49 55 47 49 48
G ZC50_GFB50 57 57 62 54 57 56 63
H SS65 55 54 60 51 54 53 60 57
I SS65_GFB65 60 59 66 57 59 59 66 63 69
J ZC75 56 55 61 52 55 54 62 58 64 60
K ZC75_GFB75 60 62 66 59 61 61 67 65 71 66 71

IRC IR-586 23
Table 9: STC ratings predicted for block walls using BRN217-12NA 290 mm
normal weight blocks. Table headings are methods of attaching 16 mm drywall.

Bare B C D E F G H I J K

Bare 49
B WS38 53 52
C WS38_GFB38 56 56 60
D RC13 51 52 56 48
E RC13_GFB19 52 50 54 50 48
F ZC50 52 50 54 50 48 49
G ZC50_GFB50 59 58 62 58 56 56 64
H SS65 56 55 59 55 53 53 61 57
I SS65_GFB65 61 61 65 61 59 59 67 63 70
J ZC75 57 55 60 56 54 54 61 58 64 59
K ZC75_GFB75 62 62 66 62 60 60 68 64 71 65 72

IRC IR-586 24
 Appendix A1
To avoid needless repetition descriptions of the materials and the construction
techniques used in this work are collected in this Appendix.

CONCRETE BLOCKS
Concrete blocks were laid-up in a running bond pattern using a Type-N mortar
mix and the mortar joints tooled to a concave finish. The walls were reinforced
horizontally by embedding a Dur-O-Wal DW100 Standard Class Wire Truss in
the mortar joint on every second course of blocks. The width of the wire truss
varied with the width of the concrete block. Single wythe wire trusses were used
on the cavity wall system. Corrugated wall ties were also used on every second
course embedded in the mortar and secured to the wood frame of the mounting
rack with nails.

1. Block Information
A - 90 mm Normal weight Concrete block

190 mm high x 390 mm long x 90 mm deep

Weight / Block = 10.9 kg
Weight / unit area = 147.3 kg/m2

B - 90 mm Split-Rib Concrete Block (Six Ribs)

190 mm high x 390 mm long x 90 mm deep

Weight / Block = 13.44 kg
Weight / unit area = 181.4 kg/m2

C- 140 mm 75% Solid Concrete Block

190 mm high x 390 mm long x 140 mm deep

Weight / Block = 17.84 kg
Weight / unit area = 240.1 kg/m2

D - 140 mm 100% Solid Concrete Block

190 mm high x 390 mm long x 140 mm deep

Weight / Block = 22.28 kg
Weight / unit area = 300.7 kg/m2

IRC IR-586 25
E - 190 mm Normal weight Concrete Block

190 mm high x 390 mm long x 190 mm deep

Weight / Block = 17.5 kg
Weight / unit area = 236.2 kg/m2

2. USG Z-FURRING CHANNELS, 50 and 75 mm

The channels are formed from 0.50 mm thick galvanized sheet metal. They were
applied horizontally on 600 mm centres with the small flange of the channel
secured to the block wall surface with 19 mm long Tapcon screws on 600 mm
centres.

50 mm Z-Bars
Flange #1, 20 mm wide, Flange #2, 30 mm wide, 50 mm deep. Weight =
0.34 kg/m.

75 mm Z-Bars
Flange #1, 25 mm wide, Flange #2, 35 mm wide, 75 mm deep. Weight =
0.52 kg/m.

3. RESILIENT METAL FURRING CHANNELS

The channels were applied horizontally on 600 mm centres with the wall
mounting flange downward, and secured to the block wall surface with 19 mm
long Tapcon screws on 600 mm centres. The channels were 13 mm deep and
formed from galvanized sheet metal 0.50 mm thick. They weighed 0.26 kg/m.

4. 65 mm NON-LOAD BEARING STEEL STUDS

The studs were placed vertically on 600 mm centres and held in place by upper
and lower metal tracks. These were positioned as close as possible to the block
surface and secured to the wood frame of the wall mounting rack with 25 mm
long wood screws. Caulking compound was applied to the backs of the upper
and lower tracks and both end studs before securing them in position. The studs
weighed 0.46 kg/m.

5. WOOD FURRING STRIPS

40 mm square wood furring strips (pine) were applied horizontally on 600 mm
centres and secured to the block wall surface with 70 mm long Tapcon screws on
600 mm centres. The furring weighed 0.65 kg/m.

6. CAVITY WALL INSULATION

A - SM Styrofoam Insulation (Blue Extruded Styrene Foam)
IRC IR-586 26
The panels were 610 mm wide x 2.44 m long x 50 mm thick. The edges were
rabbeted to form an overlap joint. The weight/unit area was 1.47 kg/m2. The
panels were applied vertically with overlapped edge joints and secured to the
block wall surface with random dabs of insulation adhesive.

B - Fiberglas Canada Cavity Wall Insulation Panels.

These were rigid Fiberglas panels faced on one side with a thin layer of
bituminous material covered with a Kraft paper. Total thickness of the facing
layer was 1 mm. The panels were 400 mm wide x 1.22 m long x 65 mm thick.
Panels were positioned with the treated surface in contact with the block wall
surface and secured with random dabs of insulation adhesive. Weight/unit area
was 4.13 kg/m2.

7. GLASS FIBRE CAVITY ABSORPTION

(Fiberglas Canada Materials)

AF300: 19 mm thick, weight/unit area = 0.4 kg/m2

AF300: 38 mm thick, weight/unit area = 0.7 kg/m2
R8: 65 mm thick, weight/unit area = 0.83 kg/m2
R12: 90 mm thick, weight/unit area = 1.16 kg/m2

8. GYPSUM WALLBOARD
Direct Application: Gypsum wallboard was applied horizontally in 1.22 m wide x
3.05 m long sheets and secured to the block wall surface with 45 mm screws
spaced between 200 mm and 250 mm at the edges and between 350 mm and
400 mm in the field.

Attachment to wall support systems: Gypsum wallboard was applied horizontally

in 1.22 m wide x 3.05 m long sheets and secured to all metal support systems
using 25 mm long drywall screws and to the wood furring with 32 mm long
drywall screws. All screws were spaced between 200 mm and 250 mm centres at
the edges and between 350 mm and 400 mm in the field. The 13 mm wallboard
weighed 9.2 kg/m2. The 16 mm wallboard weighed 10.7 kg/m2.

9. PERIMETER AND JOINT SEALS

Concrete Block Wall: After the wall was cured, a bead of caulking compound
was applied around the perimeter on both sides of the wall to seal any possible
shrinkage cracks between the mortar joint and the wood frame of the wall
mounting rack.

Gypsum Wallboard: The perimeter joint between the gypsum wallboard and the
wood frame of the mounting rack was sealed with a 25 mm wide x 3 mm thick
IRC IR-586 27
glazing and an aluminum foil adhesive tape. The horizontal joint between the
sheets of gypsum wallboard was sealed with a double layer of aluminum foil
adhesive tape.

10 - LATEX PAINT BLOCK SEALER

Two coats of CIL Super Latex Undercoat Primer were applied the wall surface
using a brush and deep pile paint roller. The first coat was allowed to dry for at
least 4 hours before applying the second coat.

Appendix A2
The table on the following pages contains the transmission loss data for all walls
tht were measured during this series. To condense the information, a codified
system for describing the walls is used. The abbreviations for the materials used
are as follows.

BLK concrete block

G gypsum drywall
WFUR wood furring
RC resilient metal channels
ZC Z-bars
SS non-load-bearing steel studs
GFB glass fibre batts
GFRP glass fibre cavity wall insulation (semi-rigid panels)
AIR air
PAI paint
STY styrofoam insulation

If a number follows the abbreviation, it gives the thickness of the material in mm.
Descriptions are generated by mentally travelling through the wall from one side
to the other describing each material encountered on the way. Underscores act
as separators for each layer. Thus the coded description

G16_RC13_GFB19_BLK190_SS65_GFB65_G16_G16

would be read as

16 mm drywall mounted on 13 mm resilient metal channels applied to one side of

a 190 mm block wall with 19 mm of glass fibre batt compressed behind the
drywall. On the second side, two layers of 16 mm drywall were supported on
65 mm steel studs. There were 65 mm thick glass fibre batts in the cavity.

This wall was not actually tested in the series and is only used to illustrate the
coding.
IRC IR-586 28
Table 10: Complete list of TL data for all configurations tested.
TestID STC Description 63 80 100 125 160 200 250 315
TL-88-356 50 BLK190 36.0 33.7 35.4 33.0 37.6 39.2 41.2 43.5
TL-88-357 55 BLK190_WFUR40_GFB38_G16 31.6 29.0 28.6 36.7 42.2 48.5 48.2 47.1
TL-88-358 59 G16_GFB38_WFUR40_BLK190_WFUR40_GFB38_G16 31.9 23.2 22.6 38.0 45.7 55.3 54.3 49.6
TL-88-360 58 G16_GFB38_WFUR40_BLK190_WFUR40_G16 31.6 23.9 21.2 34.3 42.5 53.4 52.9 49.4
TL-88-361 54 G16_WFUR40_BLK190_WFUR40_G16 32.6 25.4 20.6 30.0 34.5 44.1 46.2 45.2
TL-88-362 53 G16_WFUR40_BLK190 35.3 30.7 27.4 32.1 35.4 42.3 43.0 43.2
TL-88-366 57 G16_GFB38_WFUR40_BLK190_G16 32.9 28.1 28.7 35.9 40.8 46.6 46.4 49.1
TL-88-367 58 G16_GFB38_WFUR40_BLK190_RC13_G16 32.0 27.5 27.5 34.0 39.1 44.3 45.5 49.8
TL-88-368 51 BLK190_RC13_G16 35.7 32.4 33.4 31.4 33.9 35.4 37.7 42.5
TL-88-371 54 BLK190_RC13_GFB19_G16 34.3 30.1 29.2 30.5 36.1 41.7 47.1 52.3
TL-88-372 49 G16_GFB19_RC13_BLK190_RC13_GFB19_G16 32.9 27.1 22.2 24.9 33.9 43.4 52.4 59.2
TL-88-373 52 G16_GFB19_RC13_BLK190_RC13_G16 34.4 30.7 26.8 28.2 32.5 37.9 43.4 52.4
TL-88-374 49 G16_RC13_BLK190_RC13_G16 35.3 32.5 31.0 30.3 30.4 31.2 34.2 43.0
TL-88-379 59 G16_RC13_GFB19_BLK190_ZC50_G50_G16 28.3 25.1 26.2 35.0 41.5 48.9 52.9 59.9
TL-88-381 59 G16_GFB50_ZC50_BLK190 32.5 28.9 29.6 36.7 40.7 45.2 46.7 53.3
TL-88-384 64 G16_GFB50_ZC50_BLK190_ZC50_GFB50_G16 24.9 22.3 31.7 40.0 48.9 55.0 58.4 63.3
TL-88-385 59 G16_ZC50_BLK190_ZC50_GFB50_G16 28.2 22.9 26.1 34.8 40.9 46.0 52.7 59.6
TL-88-386 52 G16_ZC50_BLK190_ZC50_G16 28.6 23.3 21.0 27.6 32.4 35.4 41.2 50.8
TL-88-387 52 BLK190_ZC50_G16 32.8 28.6 24.4 29.8 33.1 36.2 39.1 46.0
TL-88-389 52 G16_BLK190_ZC50_G16 32.5 28.6 25.3 30.0 32.9 35.7 37.6 45.0
TL-88-390 50 BLK190_G16 36.0 32.8 30.9 35.4 33.5 35.5 35.3 41.0
TL-88-391 49 G16_BLK190_G16 34.7 33.5 30.9 35.7 33.4 34.5 34.4 39.6
TL-88-392 61 G16_BLK190_SS65_GFB65_G16 30.7 32.6 32.6 39.6 40.3 45.8 48.0 54.3
TL-88-393 60 BLK190_SS65_GFB65_G16 30.3 32.2 32.0 39.1 40.5 46.7 48.6 54.9
TL-88-397 72 G16_GFB65_SS65_BLK190_SS65_GFB65_G16 27.3 30.7 40.0 49.4 54.0 61.6 66.9 72.7
TL-88-398 65 G16_SS65_BLK190_SS65_GFB65_G16 27.3 28.5 32.1 40.7 46.6 54.8 60.6 69.0
TL-88-403 57 G16_SS65_BLK190_SS65_G16 23.5 24.4 25.2 33.0 39.6 48.4 50.7 60.5
TL-88-406 58 BLK190_SS65_G16 29.3 29.0 29.3 35.6 37.1 43.4 47.0 53.2
TL-88-407 66 G16_GFB75_ZC75_BLK190_SS65_G16 26.7 28.8 32.8 41.7 47.1 55.9 59.8 66.1
TL-88-413 73 G16_GFB75_ZC75_BLK190_SS65_GFB65_G16 26.1 29.3 40.6 50.3 55.8 63.5 66.2 68.1
TL-88-416 68 G16_ZC75_BLK190_SS65_GFB65_G16 25.7 26.6 35.2 44.2 48.3 54.6 62.3 69.5
TL-88-417 59 G16_ZC75_BLK190_SS65_G16 24.9 23.2 28.1 35.0 41.3 47.7 55.4 61.9
TL-88-418 57 G16_ZC75_BLK190 29.7 27.1 29.6 34.3 37.9 40.1 44.0 50.9
TL-88-419 57 G16_ZC75_BLK190_G16 29.9 27.0 29.3 35.0 37.3 39.8 42.5 50.3
TL-88-420 62 G16_ZC75_GFB75_BLK190_G16 29.4 31.3 35.6 42.0 44.0 47.3 49.2 56.2
TL-88-421 61 G16_ZC75_GFB75_BLK190 29.0 30.5 35.2 41.5 44.4 47.7 49.1 55.7
TL-88-422 60 G16_ZC75_GFB75_BLK190_PAI 30.4 33.8 35.8 37.5 44.5 47.5 49.6 55.3
TL-88-423 58 G16_ZC75_BLK190_PAI 29.8 29.2 29.6 33.7 37.9 40.5 46.2 52.4
TL-88-424 48 BLK190_PAI 35.4 35.3 32.2 32.6 34.6 35.8 37.0 41.5
TL-88-426 50 G16_BLK190_PAI 35.2 34.7 31.2 34.3 34.0 34.7 36.1 41.4
TL-88-427 46 G16_BLK190_PAI_G16 36.2 34.1 30.8 33.6 31.7 31.7 31.8 35.5

IRC IR-586 29
TestID 400 500 630 800 1000 1250 1600 2000 2500 3150 4000 5000 6300
TL-88-356 43.0 44.0 46.5 48.4 50.4 52.0 54.7 57.0 57.8 60.5 63.9 66.9 69.0
TL-88-357 49.4 49.5 51.9 54.6 57.0 59.9 61.9 60.6 57.7 61.1 65.6 70.3 73.8
TL-88-358 54.1 54.5 57.4 62.4 63.2 65.6 65.6 63.0 57.1 61.2 66.5 71.7 76.5
TL-88-360 54.7 54.8 58.7 60.9 61.8 64.5 65.8 63.9 57.4 61.4 66.4 72.4 77.6
TL-88-361 51.9 53.8 58.9 61.6 62.1 63.3 64.2 63.7 57.9 61.4 66.2 72.1 77.8
TL-88-362 46.9 49.0 52.9 54.7 55.9 57.7 59.1 59.1 57.0 60.2 64.6 68.9 73.2
TL-88-366 53.2 54.1 56.9 58.8 60.5 62.8 64.8 62.7 57.7 61.7 66.7 71.5 75.8
TL-88-367 55.9 58.1 60.3 62.7 64.8 66.4 66.7 66.0 62.8 66.2 70.2 74.2 77.0
TL-88-368 46.6 50.7 54.3 58.1 60.6 62.7 64.2 64.8 63.9 66.2 68.8 71.2 73.2
TL-88-371 54.6 56.8 58.7 61.2 63.6 65.1 66.4 66.3 66.7 69.2 71.8 74.6 75.9
TL-88-372 61.9 62.4 63.1 65.1 66.5 68.5 69.3 68.3 68.2 69.9 73.9 78.0 78.2
TL-88-373 59.2 62.1 62.2 64.8 65.5 67.4 68.6 68.0 67.9 69.5 72.6 76.9 78.1
TL-88-374 52.0 58.1 60.8 64.1 64.7 66.9 68.3 68.0 67.5 69.4 72.3 75.8 76.7
TL-88-379 63.7 65.1 66.0 67.7 68.3 69.1 67.7 67.8 68.4 70.4 73.1 75.6 74.4
TL-88-381 56.3 57.4 59.6 61.0 61.1 63.2 63.8 64.5 63.4 65.8 69.6 73.4 73.8
TL-88-384 67.6 70.2 71.3 74.1 74.4 74.8 72.0 70.2 68.4 70.2 73.6 76.4 75.1
TL-88-385 64.8 67.5 70.1 72.3 73.6 73.7 71.3 69.5 67.3 68.6 72.8 76.2 75.0
TL-88-386 58.4 63.2 65.8 69.1 71.7 72.2 70.8 69.3 66.3 67.2 71.4 74.9 73.9
TL-88-387 50.1 53.5 55.5 57.6 59.7 62.3 64.2 64.7 61.8 63.2 66.4 70.3 71.2
TL-88-389 50.2 54.5 57.8 60.7 62.7 64.6 66.0 65.4 61.3 63.4 67.6 73.0 73.8
TL-88-390 43.1 46.4 50.1 53.3 55.1 56.1 56.8 57.9 56.1 58.5 61.7 66.5 68.9
TL-88-391 43.4 48.1 52.8 56.4 57.7 58.6 59.9 60.0 56.4 59.5 63.5 68.0 71.8
TL-88-392 58.3 59.5 62.1 64.3 64.1 64.1 64.6 64.6 64.1 68.5 72.4 75.5 76.3
TL-88-393 57.8 57.4 59.0 60.9 61.3 62.3 63.1 63.5 63.6 68.2 71.2 73.8 75.3
TL-88-397 73.1 74.8 74.4 75.6 73.5 72.6 72.6 73.3 71.6 77.3 79.9 81.2 79.0
TL-88-398 71.5 73.9 74.0 74.6 72.3 71.2 71.3 72.2 71.0 75.6 78.9 81.1 79.2
TL-88-403 68.9 73.3 74.0 74.7 73.9 73.3 73.4 73.5 70.6 73.3 75.7 75.1 73.7
TL-88-406 58.9 62.4 62.9 65.8 66.8 66.8 65.4 65.2 65.3 68.2 73.3 77.6 78.1
TL-88-407 72.2 74.3 74.6 75.7 74.8 74.0 74.1 73.3 68.9 72.1 78.2 80.8 78.5
TL-88-413 74.7 76.7 77.8 78.6 77.3 74.4 74.3 74.3 71.7 75.8 79.9 81.0 78.5
TL-88-416 72.4 74.3 76.1 77.1 76.0 73.8 73.0 70.8 69.4 73.5 78.1 81.2 79.6
TL-88-417 69.7 73.1 74.8 76.4 75.7 73.5 72.6 69.3 67.8 71.9 77.3 80.1 78.3
TL-88-418 54.1 56.0 58.4 60.5 61.6 63.5 64.6 62.9 60.3 63.8 69.3 72.4 74.9
TL-88-419 55.7 59.7 63.1 64.0 63.7 66.6 67.9 64.3 59.9 63.6 69.6 73.0 75.9
TL-88-420 60.7 63.5 64.7 64.8 63.6 66.5 68.6 66.5 62.2 66.1 71.3 74.7 76.4
TL-88-421 58.2 59.2 60.3 61.7 62.3 64.2 65.3 64.6 62.1 65.8 70.7 73.8 75.5
TL-88-422 58.5 59.6 60.4 61.3 62.1 64.1 65.1 64.4 62.2 65.6 70.7 73.7 76.0
TL-88-423 55.7 58.2 60.4 62.0 61.6 63.9 65.1 64.9 61.8 65.1 70.4 73.3 74.9
TL-88-424 42.0 44.1 45.6 47.0 48.3 50.1 53.3 56.0 56.2 58.8 62.7 65.7 67.7
TL-88-426 44.3 47.5 50.6 53.6 55.5 58.8 62.1 62.8 61.0 63.5 67.7 71.6 74.3
TL-88-427 38.7 44.2 50.0 55.9 59.6 63.0 65.5 65.5 63.4 64.7 68.4 73.9 76.5

IRC IR-586 30
 Frequency, Hz
S
TestID T Description 63 80 100 125 160 200 250 315
C
190/90 mm cavity walls
TL-88-431 79 BLK90_AIR100_GFRP65_BLK190_G16 42.1 49.3 52.5 57.4 59.1 63.8 66.5 73.1
TL-88-432 67 BLK90_AIR115_STY50_BLK190_G16 40.7 44.5 48.8 52.0 49.2 48.7 54.3 64.6
90/90 mm cavity walls
TL-88-436 73 BLK90_AIR60_GFB65_BLK90 39.7 46.5 50.5 53.8 53.7 57.1 61.7 66.8
TL-88-440 77 BLK90_AIR60_GFRP65_BLK90_G16 41.1 48.3 51.8 57.3 59.2 61.5 64.9 70.5
TL-88-441 69 BLK90_AIR125_BLK90_G16 39.6 45.1 50.8 52.4 51.6 53.5 57.3 60.1
TL-88-442 69 BLK90_AIR75_STY50_BLK90_G16 40.0 44.3 47.8 50.0 50.9 53.4 56.6 59.6
90 mm split rib on chamber lip
TL-88-447 44 BLK90 32.3 30.5 30.3 31.9 32.4 34.5 36.9 37.7
90/90 mm on test frame
TL-88-459 62 BLK90_AIR25_GFRP65_BLK90_G16 36.9 42.3 46.0 49.3 52.8 51.9 53.6 51.7
90 mm normal on frame
TL-88-461 44 BLK90 30.2 28.3 29.1 33.1 33.4 34.7 36.2 36.9
140 mm, 75% solid
TL-88-473 47 BLK140 35.0 33.3 34.2 36.8 38.4 35.6 34.4 38.1
TL-88-474 61 G16_SS65_GFB65_BLK140 32.8 35.7 38.8 44.3 46.1 47.2 48.0 52.4
TL-88-475 67 G16_SS65_GFB65_BLK140_WFUR40_GFB38_G13 30.6 30.1 35.0 45.7 52.8 56.3 55.3 57.4
TL-88-476 55 BLK140_WFUR40_GFB38_G13 31.8 27.5 30.5 38.1 44.5 45.0 42.2 45.1
TL-88-477 56 PAI_BLK140_WFUR40_GFB38_G13 33.5 28.6 30.2 37.5 43.9 44.9 41.5 46.2
TL-88-478 48 PAI_BLK140 37.2 34.5 36.3 37.7 39.1 36.0 33.8 37.5
140 mm, 100% solid
TL-88-487 50 BLK140 38.0 31.8 34.7 38.2 36.3 35.3 36.6 40.8
TL-88-488 50 PAI_BLK140 38.8 34.4 34.2 37.4 34.4 33.6 37.3 41.6
TL-88-489 58 PAI_BLK140_GFB38_WFUR40_G13 34.3 29.5 28.4 37.9 44.3 43.7 43.6 47.6

IRC IR-586 31
 Frequency, Hz
TestID 400 500 630 800 1000 1250 1600 2000 2500 3150 4000 5000 6300
190/90 mm cavity walls
TL-88-431 75.8 78.4 80.7 83.6 84.4 84.3 84.1 86.6 86.4 86.9 82.9 82.7 80.5
TL-88-432 68.9 75.2 76.8 76.1 75.4 78.8 80.7 84.1 84.7 85.9 82.5 82.4 79.8
90/90 mm cavity walls
TL-88-436 70.9 74.9 77.3 74.2 75.8 75.8 74.7 80.9 83.1 84.8 82.5 81.7 78.90
TL-88-440 71.7 76.4 80.8 79.0 81.7 82.3 83.4 85.6 85.8 86.6 82.9 82.0 79.0
TL-88-441 61.6 70.4 76.0 75.2 77.8 77.2 78.4 83.4 83.5 84.7 82.0 81.2 79.0
TL-88-442 61.0 68.6 73.8 74.2 78.0 78.1 77.4 80.6 82.8 85.6 81.7 81.4 79.2
90 mm split rib on chamber lip
TL-88-447 39.0 39.3 40.5 42.3 43.5 45.0 46.8 49.3 50.4 51.5 54.9 58.3 59.9
90/90 mm on test frame
TL-88-459 52.7 56.8 61.5 63.8 65.7 67.3 68.2 70.6 75.2 79.4 80.5 81.8 79.7
90 mm normal on frame
TL-88-461 36.9 39.5 40.8 43.5 44.6 45.9 46.4 48.3 49.3 53.4 57.1 58.0 58.2
140 mm, 75% solid
TL-88-473 40.3 42.4 45.2 48.2 51.2 53.5 54.8 57.3 60.6 63.1 64.4 68.8 72.6
TL-88-474 56.4 58.0 60.3 62.7 64.7 66.2 65.7 67.2 69.2 73.0 76.2 80.1 81.0
TL-88-475 62.4 63.0 65.2 67.7 70.6 71.6 72.8 72.5 72.9 73.7 77.6 81.2 81.9
TL-88-476 48.8 50.5 53.2 56.5 60.0 62.7 64.4 65.6 66.2 64.0 67.4 73.8 78.6
TL-88-477 49.5 50.9 53.9 56.8 59.2 62.2 64.1 65.7 66.4 63.8 67.2 73.9 78.8
TL-88-478 40.4 43.0 46.0 48.6 51.8 53.9 55.4 58.4 62.1 64.2 65.0 68.8 72.6
140 mm, 100% solid
TL-88-487 44.9 46.1 49.4 52.7 54.8 57.0 59.6 61.5 63.9 66.0 68.6 71.6 73.6
TL-88-488 44.5 46.3 50.1 52.8 55.5 57.7 60.2 61.8 64.1 66.2 68.4 71.0 72.6
TL-88-489 52.0 53.6 58.2 59.9 62.6 65.0 66.9 67.9 68.5 66.7 69.4 74.4 76.4

IRC IR-586 32