CBA/CBI
Sound attenuating transfer unit
QUICK FACTS
○○ For transferring air through walls
A I R F L O W - P R E S S U R D R O P - Rw V A L U E S
Wall holes
10 Pa
20 Pa
Rw
○○ Flow range < 50 l/s
CBA
l/s
m3/h
l/s
m3/h
∅100
25
90
35
126
○○ Circular holes
∅125
29
104
42
151
36
○○ Easy to install
∅160
35
126
50
180
34
○○ Available in alternative colours
CBI
m3/h
l/s
10 Pa
l/s
20 Pa
m3/h
39
Rw
∅80
13
47
18
65
41
∅100
18
65
25
90
39
CBA/CBI
Technical description
Design
The CBA/CBI are rectangular transfer air units consisting
of two sections: a sound attenuating baffle and a mounting frame.
The sound attenuating baffle is filled with acoustic
attenuation material with a reinforced surface layer and
has an open slot in each short side. The mounting frame
is rectangular and designed for cutting a round hole in
the wall. The unit comes in two versions, CBA and CBI.
The CBA version is larger in height than the CBI and can
handle a larger airflow at the same pressure drop.
Materials and surface treatment
The sound attenuator is manufactured in sheet steel and
aluminium. The mounting frame is manufactured in galvanised sheet steel. The sound attenuator is painted with
our pure white standard paint, RAL 9003/NCS S 0500-N.
The unit is also available in other standard colours: Dusty
grey 7037, white aluminium RAL 9006, jet black RAL
9005, grey aluminium RAL 9007 and white RAL 9010.
Accessories
Disc valve:
CBAT 1. This is used on one side of the wall when only
one sound attenuation is required. It is suitable for
use with both version. See Figure 1.
Wall sleeve:
VGC. Circular telescopic wall duct made in galvanized
sheet steel.
Installation
Hole making size according to table under section Dimensions and weights. The fixing frame is screwed to the wall.
The acoustic baffle is pressed over the springs in the fixing
frame. See figure 1.
Figure 1. Application.
1. Concealed installation in corridor.
2. Visible installation in corridor. CBA/CBI supplemented with
either a disc valve or a second CBA/CBI.
3. Visible installation in a corridor. Double CBA/CBI units.
4. As in (3) but using the wall sleeve VGC.
2
Swegon reserves the right to alter specifications.
20150101
CBA/CBI
Planning
The units can be used on both sides of the hole cut in
the wall or on only one side. The other side can then be
covered with a disc valve or left open, depending on the
acoustic demands. See Figure 1.
The units are designed primarily for batten walls with
plasterboard or similar covering. If the units are installed
in a concrete wall or if a connecting tube of steel is used,
the sound reduction value (RW ) is reduced by 10 dB.
A transfer unit should be chosen so that the insulating
properties of the wall are not reduced. To quickly determine this, a rule of thumb can be used:
RW transfer air unit or acoustic class of wall + 5 dB(A)
To calculate the resulting Rw value for the wall see examples A and B below.
Table 1 shows the reduction value R, and the Rw value for
transfer units with reference to 1 m2 transmission area. The
measurements were carried out according to ISO 140-1, 2, 3.
The RW value was evaluated according to ISO 717-1.
The values shown apply to holes that are not fitted with
wall sleeves.
If a metal sleeve is used the values will be reduced by 10
dB. The measured values for a single unit do not include
the disc valve.
Maintenance
The grille can be cleaned when necessary using lukewarm
water and detergent.
Environment
The Declaration of construction materials is available at
www.swegon.com.
Table 1, Reduction values
Model
CBA
CBI
Hz
One unit on each side of the hole
125
250
500
1K
2K
One unit
RW, 1 m2
Ø100
29
35
43
49
51
39
40
Ø125
28
34
40
46
51
36
38
Ø160
28
34
37
43
50
34
36
Ø80
30
38
44
50
51
41
42
Ø100
30
37
42
47
51
39
40
Wall hole, mm
20150101
RW, 1 m
Swegon reserves the right to alter specifications.
3
CBA/CBI
Sizing
Airflow – Pressure drop
• The table states airflow capacities for one (1) transfer
air unit at 10 and 20 Pa total pressure drop, and for
various hole sizes through the wall.
(dB)
Table 2.
Model
CBA
CBI
Hole size
Max. air flow in l/s
in wall, mm
10 Pa
20 Pa
100
25
35
125
29
42
160
35
50
80
13
18
100
18
25
Engineering graphs – decrease in the
reduction values for walls
The graphs show the reduction value of walls when a
transfer unit is installed.
Example A – Calculation with one (1) CBA unit:
1.A standard CBA 100 is mounted in a wall with an area of
S0 = 10 m2, the hole cut having a diameter of 100 mm.
2.RW wall = 45 dB.
RW transfer unit = 39 dB (see table 1, Reduction values).
3.Difference wall - transfer unit = 6 dB.
4.Follow the points on the axes of the graph for 6 dB
of the Y-axis and 10 m2 of the X-axis. The intersection
of these two lines indicates how much the reduction
value of the wall decreases when a transfer unit is
installed - in this case about 1 dB (1,4 ≈ 1 dB).
5.In the wall in this example, the total RW -value 44 dB (45
–1).
(m2)
Figure 2. Graph – Difference in dB: R0 –R1
Ratio of areas in m2: S0 /S1
Example B – Calculation with two (2) CBA units:
1.Two CBA 100 units are mounted in a wall with an
area of S 0 = 10 m2, the hole cut having a diameter of
100 mm for each unit.
2.RW wall = 45 dB.
RW transfer unit = 39 dB.
3.Difference wall - transfer unit = 6 dB.
4.Follow the points on the axes of the graph for 6 dB of
the Y-axis and 10 m2 of the X-axis. Just as in example A
above, we can see that the reduction value of the wall
decreases by about 1 dB. I.e. with a transfer unit in the
wall, the resulting Rw = 44 dB.
5.To see how both transfer units work in unison, we
can rework the above calculation.
6.Rw wall = 44 dB.
Rw transfer unit = 39 dB
7.Difference wall - transfer unit = 5 dB.
8.Follow the points on the axes of the graph for 5 dB of the
Y-axis and 10 m2 of the X-axis. We can see that the reduction value of the wall now decreases by about 1 dB. So
with two transfer units installed, the  RW = 43 dB (44 –1).
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Swegon reserves the right to alter specifications.
Figure 3. Area ratio between the wall surface and the area of the
diffuser .
Symbols:
R0 = the reduction value of the wall
R1 = the reduction value of the unit alt. window/door
S 0 = the area of the wall including windows/doors
S1 = the reference area for the unit = 1 m2
20150101
CBA/CBI
Dimensions and weights Order key
CBA/CBI
Product
A
B
CBA
220
CBI
170
Sound attenuating transfer unit
C
ØD
Weight, kg
160
210
160
1.2
Version:
110
160
125
1.0
NOTE! These devices are not supplied in pairs.
Sound attenuating transfer unit
VGC
CBA
a
CBI
a
Version
Size
ØD
C
80
80
80-160
100
100
80-160
125
125
80-160
Disc valve
160
160
80-160
Version:
NOTE! These devices are not supplied in pairs.
Accessories
CBAT 1
a
-aaa
Size: 80, 100, 125, 160
Wall sleeve
VGC
a
-aaa
Version:
Size: 80, 100, 125, 160
Specification example
Figure 4. CBA.
TG XX
Swegons rectangular attenuating air transfer unit of the
type CBA having the following functions:
• Manufactured in extruded aluminium
• Acoustic attenuation material with reinforced surface
layer
• Powder-coated in white
Accessories:
Disc valve:
CBAT 1 - bbb
xx items
Size:
CBAa
xx items
Figure 5. VGC.
20150101
Swegon reserves the right to alter specifications.
5