HVAC
ROCKWOOL® productSHEET
600 313-02/14_V1 (en)
ROXUL Acoustoflex
Sound Attenuation
Flexible Duct
General Product Information
Acoustoflex is a quality flexible duct, factory fabricated from a
non-woven permeable fabric, mechanically interlocked by a
corrosion resistant metal spiral helix. Glass wool insulation is
factory applied and sheathed with an outer aluminium laminate
vapour barrier.
The duct provided excellent sound attenuation properties,
presents low airflow resistance and dampens mechanical
vibrations. Its high tensile steel helix can withstand rough
handling. The duct maintains its full diameter on bends and can
be compressed for ease of transportation.
HVAC
ROCKWOOL® productSHEET
600 313-02/14_V1 (en)
ROXUL Acoustoflex Sound Attenuation
Flexible Duct
Common applications
Pressure Drop Chart
PRESSURE DROP – STRAIGHT RUNS
100
90
80
70
60
Acoustoflex is commonly used in commercial and residential air
handling applications. It is designed to convey air and provides
easy alignment between rigid duct and air terminals such as
diffusers. Acoustoflex is recommended for use in low and
medium pressure HVAC system.
.01
10
.02
.03
.04 .05 .06.07.08.09 1
16
2
3
4
5
6 7 8 9 10
2
3
4
5
6
60
VEL
OCIT
Y (4
50
0m
35
40
/se
7 8 9 10
100
90
80
70
60
c)
50
40
30
30
30
25
20
20
20
10
9
8
7
6
Dimensions
10
9
8
7
6
15
5
5
4
Packaging
Each length of insulated Acoustoflex is compressed to
approximately 1600mm to 2000mm and packed in strong clear
plastic tubing to facilitate handling and storage.
Technical Parameters
Rated air velocity: 20 metres/second
Service temperature (insulated duct): Between -20°C to
+120°C
Reaction to fire: Rated as Class O for insulated duct and
tested to BS475 Part 6: 1988 & Part 7: 1997 under the
requirement of FSSB
Thermal Resistance (R) values for insulated ducts
16kg/m³ x 25mm thick 0.69 m²K/W
24kg/m³ x 25mm thick 0.75 m²K/W
32kg/m³ x 25mm thick 0.77 m²K/W
32kg/m³ x 50mm thick 1.50 m²K/W
178
128
357
510
0.5
ER
S(
0.5
1.0
0.9
0.8
0.7
0.6
408
459
mm
)
5
305
254
203
229
1.0
0.9
0.8
0.7
0.6
0.4
ET
0.4
0.3
CT
D
IAM
0.3
0.2
2
152
102
77
3
0.2
DU
PRESSURE LOSS (mm WATER/M)
2
0.1
0.1
.01
10
.02
.03
.04 .05 .06.07.08.09 1
16
2
3
4
5
6 7 8 9 10
2
3
4
5
6
7 8 9 10
AIRFLOW VOLUME (m3/SEC)
BENDS - Pressure drop caused by a typical 90° bend of inside radius equal to duct diameter, is equivalent to 17 diameters of straight duct.
In addition to providing thermal insulation, Acoustoflex has sound
attenuation properties. The following graph for sound attenuation in
ducts has been based on tests undertaken by the National University
of Singapore, School of Building & Real Estate (Acoustics Research
Laboratory, Report No. 990405). The graph shows the results on 3
metre lengths of diameters 150mm, 200mm and 250mm
Acoustoflex. A full comprehensive report can be supplied on request.
Measured Static Insertion Loss of 150mm, 200mm and 250mm diameters of Acoustoflex duct
Tested in accordance with BS4718/1971 “Methods of test for silencers for air distribution systems”.
60
STATIC INSERTION LOSS (dB)
Diameter
Nominal diameters from 75mm to 250mm in 25mm increments and 300mm to 500mm in 50mm increments.
Insulation types
Glass wool in 16kg/m3x25mm, 32kg/m3x25mm and 32kg/
m3x50mm
Length
10 m per length
5 m per length for ducts with insulations in 32kg/m3x50mm
for diameter from 300mm to 500mm.
4
10
3
50
150mm duct
40
30
250mm duct
200mm duct
20
10
0
63
125
250
500
1000
2000
4000
8000
FREQUENCY (Hz)
www.rockwoolasia.com
ROCKWOOL Building Materials
(Singapore) Pte Ltd
No. 8, Tuas Avenue 2
Jurong Town
Singapore 639448
T (+65) 6861 4722 / 6863 6233
F (+65) 6862 3533 / 6863 2933
Disclaimer: The information contained in this
data sheet is believed to be correct at the date
of publication. ROCKWOOL does not accept
responsibility for the consequences of using
ROXUL Acoustoflex Sound Attenuation
Flexible Duct in applications different from
those described above.