OWAtecta
Sound Absorption
®
Acoustic Performance in Metal
OWAtecta® metal ceilings offer a versatile combination of design and performance that can be used in a wide variety of applications. The product range
offers systems and patterns that can provide sound absorption, sound insulation
and even fire resistance.
Communication and Concentration in balance
Sound Absorption
Employees are an important company asset and the provision of a
Sound absorption measures the amount of sound energy absorbed by
comfortable, attractive working environment is very important.
a material and is one of the most important performance considera-
Acoustically, areas should allow effective communication between
tions in the acoustic design of a room. As well as providing the right
co-workers without being intrusive, a balance between communica-
balance between reflection and absorption, the selection quantity and
tion and concentration. OWAtecta ceilings can be used as a key
positioning of sound absorbing materials are key factors in achieving
element in the design of an efficient workspace providing acoustic
the correct reverberation time for the rooms intended use.
®
control, a range of versatile systems and the ability to integrate
services within the ceiling plane. As an introduction we explain
Sound Absorption Coefficient
below some of the acoustic terms you may encounter.
The sound absorption coefficient of a material describes its ability
to absorb sound and is measured over a number of specific
Reverberation Time (RT)
frequencies. The result is expressed as a number between 0 and
Reverberation time is the oldest and best known performance
1 where 0 is total reflection and 1 is total absorption. If the
criteria in the field of acoustics. It is measured in seconds and
coefficient is multiplied by 100, it provides the percentage of
is defined as the time taken for a generated sound to decay by
incident sound that is absorbed.
60 dB once the sound source has been stopped.
a = 0,75 means
L
[dB]
a = 0,75 x 100 % = 75% sound absorption
(The remaining 25% is sound reflection)
Generated
sound
Sound source stopped
Absorption coefficient
e.g. 0.75
Absorption
e.g. 75 %
60 dB
Background
noise
t
Reflection
e.g. 25 %
t [s]
Reverberation time: t = T60 [s]
Equivalent sound absorption area “A”
The equivalent sound absorption area (A) is the amount of a
Every room is different
material with a sound absorption of a = 1 (100%) that would be
The optimum reverberation time for a room is dependant on its
needed to provide the required reverberation time. The equation
intended use be it office, conference room, classroom, cafeteria or
A = a x S can be used to calculate the equivalent surface area
library. Lists of recommended reverberation times for a variety of
of a material with a sound absorption (“a”) of less than 1.
applications are available from a number of recognised sources
For example a surface area (S) of 10m2 with a sound absorption
such as DIN 18041.
of a = 0.70 (70%) provides the equivalent to a surface area (A)
Measurement of the rooms RT and any subsequent calculations will
of 7m2 using a product with an absorption value of a = 1. Using
be dependant on a number of the room’s physical attributes. These
this equation it is easy to calculate the minimum surface area
include the dimensions and shape of the room, the construction
required using a product with a known sound absorption
and materials used for the interior surfaces and the type and
performance.
position of any other materials used in the room.
Reverberation time and Sound Absorption
Sound Absorption Coefficient as
The reverberation time in a room can be calculated by using the
Materials are tested for their ability to absorb sound by being placed
formula shown below where:
in a reverberation chamber and tested in accordance with EN ISO
• Reverberation time,T
354. The test is carried out over 18 separate frequencies from
• Volume of the room in m , V
100 Hz to 5000 Hz and the results reported individually as a sound
3
• Total sound absorption of surfaces, A
absorption coefficient (as) between 0.00 (total reflection) and
1.00 (total absorption). Using these results a number of single figures
T = 0.163 •
V
A
can be produced.
Reverberation time = 0.163 •
Room volume
Sound Absorption Coefficient ai.M.
Sound absorption of surfaces
The test results from the 18 frequencies are averaged to provide a
A =afloor • surface areafloor + awall • surface areawall +
aceiling • surface areaceiling + other absorbing surfaces
A ...is the total sound absorption of the surfaces
within the room.
single mid range value.
e.g. ai. M. = 0.62 (62 %)
Weighted Sound Absorption Coefficient aw
The International standard EN ISO 354 does not provide a method to
calculate a single indicative figure result from the 18 frequencies. This is
Sound reductionΔL through sound absorption
provided by EN ISO 11654 with the use of a predetermined curve at 500
When sound absorbing materials are placed in a room the
Hertz. The result is expressed as an ‘aw’ figure. To further simplify and
sound level decreases and results in a more diffuse sound field
make comparison of products easy Appendix B of EN ISO 11654
DL = 10 • lg
A2
A1
= 10 • lg
T2
T1
in[dB]
In this equation A1 represents the empty room and A2 the room
provides a simple classification system where the ‘aw’ result falls into
Absorption Classes ranging from “A – E” plus “NC”
Absorption Class
aw-value [-]
A
0.90; 0.95; 1.00
after the introduction of the absorbing materials. NB the full
B
0.80; 0.85
effect of the absorbing materials will not be realised if the
C
0.60; 0.65; 0.70; 0.75
D
0.30; 0.35; 0.40; 0.45; 0.50; 0.55
E
0.15; 0.20; 0.25
not classified
0.00; 0.05; 0.10
subject or measuring equipment is placed in the immediate
vicinity or in a direct line with the sound source.
Single figure sound absorption
To enable simple comparison of products the sound absorption
performance is also shown as a single figure. However the single
figures results do not reflect the full performance and are generally
not adequate for an accurate acoustic calculation.
Noise Reduction Coefficient (NRC)
The American standard ASTM 423 provides similar test criteria to EN ISO
354 and also provides a method for calculating a single figure result
called a “Noise Reduction Coefficient” or” NRC”. This is calculated using
the following equation.
a250Hz + a500Hz + a1000Hz + a2000Hz
NRC =
4
The result is reported in increments of 0.05
Example: NRC =
0.39 + 0.58 + 0.73 + 0.61
4
= 0.58
NRC = 0.60
Building Acoustics
Sound Attenuation
Room to Room Airborne Sound Reduction
Diagram
(Dn,f,w or Dn,c,w)
In many buildings partition walls are not installed to the
soffit, but extend only to suspend ceiling level. This
makes partitions easier to move and provides a more
flexible workspace.
Ceiling
cavity
Where this type of construction is used care must be
taken to ensure that airborne sound transmission
through the common cavity is controlled, especially
between sensitive areas.
Office1
The effective reduction of airborne sound between horizontally
adjacent rooms can be increased in several ways
• Insertion of high-density OWAcoustic mineral wool boards in the metal tiles
• Insertion of an encapsulated mineral wool insulation pad in the metal tiles
• Insertion of a mineral wool insulation pad sealed into the metal tile using a foil backing
• Insertion of mineral wool insulation pad into the metal tile with a plain, non-perforated metal backing panel
• Installation of vertical cavity barriers above walls/partitions
Single Transit Airborne Sound Reduction (Rw)
With the correct selection of system, surface design and
additional back treatment, OWAtecta metal ceilings can
significantly reduce the impact of noise generated in the cavity
by services such as heating and air conditioning.
Noise from the ceiling cavity
Office 2
OWAtecta® standard perforations – sound absorption summary
Product
Sound absorption coefficient ap
Void depth
125
250
500
1000
2000
4000
NRC
aw
Absorption
class
OWAtecta perfora
E200
0,25
0,65
0,65
0,40
0,35
0,25
0,50
0,40 (LM)
D
OWAtecta Rg0701
E200
0,35
0,60
0,70
0,60
0,50
0,45
0,55
0,55 (L)
D
OWAtecta Rd1522
E200
0,25
0,65
0,85
0,65
0,70
0,70
0,70
0,70
C
OWAtecta Rg1821
E200
0,20
0,55
0,75
0,60
0,65
0,75
0,60
0,65
C
OWAtecta Rd2508
E200
0,30
0,65
0,80
0,70
0,70
0,70
0,70
0,75
C
OWAtecta Rg2516
E200
0,35
0,70
0,85
0,75
0,75
0,75
0,75
0,80
B
OWAtecta Rg3012
E200
0,30
0,65
0,85
0,70
0,75
0,80
0,70
0,75
C
OWAtecta Rg3024
E200
0,20
0,60
0,80
0,60
0,65
0,75
0,65
0,65
C
OWAtecta Rg4022
E200
0,25
0,60
0,85
0,65
0,70
0,80
0,70
0,70
C
OWAtecta Lg25042
E200
0,20
0,60
0,80
0,60
0,70
0,75
0,65
0,70
C
OWAtecta Qg4025
E200
0,25
0,60
0,80
0,65
0,70
0,80
0,65
0,70
C
OWAtecta Qg8043
E200
0,25
0,60
0,80
0,60
0,70
0,75
0,65
0,70
C
5,0
Sound Absorption Coefficient
OWAtecta® perfora
1,0
0,8
0,6
0,4
0,2
0,0
5,0
5,
0
125
0,5
0,
5
250
500
1000
Frequency f [Hz]
2000
4000
Sound Absorption
Void Depth E50
Void Depth E100
Void Depth E200
Void Depth E400
Freq. [Hz]
as
ap
as
ap
as
ap
as
ap
125
0,04
0,05
0,11
0,10
0,23
0,25
0,38
0,45
250
0,24
0,20
0,43
0,45
0,65
0,65
0,66
0,60
500
0,60
0,60
0,79
0,75
0,70
0,65
0,40
0,45
1000
0,70
0,70
0,56
0,55
0,38
0,40
0,42
0,40
2000
0,36
0,35
0,33
0,35
0,32
0,35
0,33
0,35
4000
0,26
0,25
0,27
0,25
0,26
0,25
0,21
0,20
NRC
0,45
0,55
0,50
0,45
aw
0,40 (M)
0,40 (LM)
0,40 (LM)
0,35 (L)
5,0
Sound Absorption Coefficient
OWAtecta® Rg0701
1,0
0,8
0,6
0,4
0,2
0,0
5,0
125
0,7
250
500
1000
Frequency f [Hz]
2000
4000
Sound Absorption
Void Depth E50
Void Depth E100
Void Depth E200
Void Depth E400
Freq. [Hz]
as
ap
as
ap
as
ap
as
ap
125
0,08
0,15
0,20
0,20
0,30
0,35
0,42
0,45
250
0,42
0,40
0,57
0,55
0,54
0,60
0,60
0,55
500
0,66
0,65
0,75
0,75
0,69
0,70
0,55
0,55
1000
0,72
0,70
0,70
0,70
0,55
0,60
0,57
0,55
2000
0,60
0,60
0,51
0,50
0,51
0,50
0,52
0,55
4000
0,44
0,45
0,45
0,45
0,45
0,45
0,40
0,40
NRC
0,60
0,65
0,55
0,55
aw
0,60
0,55
0,55 (L)
0,55
3,5
Sound Absorption Coefficient
OWAtecta® Rg1821
3,5
1,0
0,8
0,6
0,4
0,2
0,0
1,8
125
250
500
1000
Frequency f [Hz]
2000
4000
Sound Absorption
Void Depth E50
Void Depth E100
Void Depth E400
Freq. [Hz]
as
ap
as
ap
as
ap
as
ap
125
0,05
0,05
0,09
0,10
0,19
0,20
0,35
0,40
250
0,19
0,15
0,34
0,35
0,56
0,55
0,65
0,65
500
0,34
0,35
0,61
0,60
0,80
0,75
0,49
0,55
1000
0,64
0,65
0,84
0,80
0,50
0,60
0,56
0,60
2000
0,86
0,85
0,53
0,60
0,61
0,65
0,64
0,65
4000
0,60
0,65
0,65
0,70
0,74
0,75
0,69
0,70
NRC
0,50
0,60
0,60
0,60
aw
0,40 (MH)
0,60
0,65
0,60 (L)
5,5
Sound Absorption Coefficient
OWAtecta® Rg2508
11,0
Void Depth E200
1,0
0,8
0,6
0,4
0,2
0,0
125
5,5
2,5
11,0
250
500
1000
Frequency f [Hz]
2000
4000
Sound Absorption
Void Depth E50
Void Depth E100
Void Depth E200
Void Depth E400
Freq. [Hz]
as
ap
as
ap
as
ap
as
ap
125
0,08
0,10
0,16
0,15
0,29
0,30
0,42
0,45
250
0,32
0,30
0,51
0,50
0,60
0,65
0,71
0,70
500
0,59
0,55
0,78
0,75
0,82
0,80
0,60
0,65
1000
0,80
0,80
0,85
0,85
0,62
0,70
0,67
0,70
2000
0,82
0,80
0,65
0,70
0,67
0,70
0,70
0,70
4000
0,61
0,65
0,64
0,65
0,68
0,70
0,65
0,65
NRC
0,65
0,70
0,70
0,65
aw
0,55 (MH)
0,75
0,75
0,70
1,0
0,8
0,6
0,4
0,2
5,5
Sound Absorption Coefficient
OWAtecta® Rg2516
0,0
5,5
125
2,5
250
500
1000
Frequency f [Hz]
2000
4000
Sound Absorption
Void Depth E50
Void Depth E100
Void Depth E200
Void Depth E400
Freq. [Hz]
as
ap
as
ap
as
ap
as
ap
125
0,11
0,10
0,20
0,20
0,29
0,35
0,35
0,40
250
0,30
0,30
0,53
0,50
0,75
0,70
0,78
0,70
500
0,56
0,55
0,81
0,80
0,88
0,85
0,68
0,70
1000
0,77
0,80
0,93
0,90
0,70
0,75
0,74
0,75
2000
0,89
0,90
0,71
0,75
0,72
0,75
0,78
0,80
4000
0,69
0,75
0,69
0,70
0,73
0,75
0,77
0,75
NRC
0,65
0,75
0,75
0,75
aw
0,55 (MH)
0,75
0,80
0,75
1,0
0,8
0,6
0,4
0,2
7,5
Sound Absorption Coefficient
OWAtecta® Rg4022
0,0
7,5
125
4,0
250
500
1000
Frequency f [Hz]
2000
4000
Sound Absorption
Void Depth E50
Void Depth E100
Void Depth E200
Void Depth E400
Freq. [Hz]
as
ap
as
ap
as
ap
as
ap
125
0,05
0,10
0,12
0,15
0,22
0,25
0,37
0,45
250
0,22
0,20
0,39
0,40
0,59
0,60
0,71
0,70
500
0,43
0,40
0,70
0,70
0,87
0,85
0,55
0,65
1000
0,73
0,70
0,92
0,90
0,56
0,65
0,62
0,65
2000
0,90
0,90
0,64
0,70
0,68
0,70
0,71
0,70
4000
0,66
0,70
0,75
0,80
0,78
0,80
0,74
0,75
NRC
0,55
0,65
0,70
0,65
aw
0,45 (MH)
0,70
0,70
0,70
Sound Absorption Coefficient
OWAtecta® Lg25042
t1=5,0
3,0
25,0
1,0
0,8
0,6
0,4
0,2
0,0
O
125
t2=Schritt
250
500
1000
Frequency f [Hz]
2000
4000
Sound Absorption
Void Depth E50
Void Depth E100
Void Depth E400
Freq. [Hz]
as
ap
as
ap
as
ap
as
ap
125
0,05
0,05
0,10
0,10
0,20
0,20
0,37
0,40
250
0,20
0,20
0,35
0,35
0,56
0,60
0,69
0,70
500
0,39
0,40
0,64
0,60
0,81
0,80
0,51
0,60
1000
0,67
0,70
0,86
0,85
0,52
0,60
0,58
0,60
2000
0,87
0,85
0,56
0,65
0,64
0,70
0,68
0,65
4000
0,61
0,70
0,65
0,70
0,72
0,75
0,68
0,70
NRC
0,55
0,60
0,65
0,60
aw
0,45 (MH)
0,60 (M)
0,70
0,65 (L)
2,0
Sound Absorption Coefficient
OWAtecta® Rd1522
4,0
Void Depth E200
0,8
0,6
0,4
0,2
0,0
2,0
4,0
1,0
125
1,5
250
500
1000
Frequency f [Hz]
2000
4000
Sound Absorption
Void Depth E50
Void Depth E100
Void Depth E200
Void Depth E400
Freq. [Hz]
as
ap
as
ap
as
ap
as
ap
125
0,08
0,05
0,12
0,10
0,24
0,25
0,42
0,40
250
0,16
0,15
0,31
0,30
0,66
0,65
0,83
0,75
500
0,35
0,35
0,72
0,70
0,85
0,85
0,52
0,60
1000
0,67
0,70
0,88
0,85
0,57
0,65
0,67
0,70
2000
0,86
0,85
0,57
0,65
0,68
0,70
0,70
0,70
4000
0,63
0,70
0,65
0,70
0,67
0,70
0,74
0,75
NRC
0,50
0,60
0,70
0,70
aw
0,40 (MH)
0,60 (M)
0,70
0,70 (L)
Sound Absorption Coefficient
OWAtecta® Qg8043
8,0
8,0
12,2
1,0
0,8
0,6
0,4
0,2
0,0
12,2
125
250
500
1000
Frequency f [Hz]
2000
4000
125
250
500
1000
Frequency f [Hz]
2000
4000
Sound Absorption
Void Depth E400
as
ap
as
ap
125
0,21
0,25
0,44
0,45
250
0,57
0,60
0,72
0,75
500
0,83
0,80
0,52
0,55
1000
0,53
0,60
0,61
0,65
2000
0,65
0,70
0,68
0,70
4000
0,75
0,75
0,68
0,70
NRC
0,65
0,65
aw
0,70
0,65 (L)
5,15
10,3
OWAtecta® Rd3012
Sound Absorption Coefficient
Void Depth E200
Freq. [Hz]
1,0
0,8
0,6
0,4
0,2
0,0
5,15
10,3
3,0
Sound Absorption
Void Depth E200
Freq. [Hz]
as
ap
125
0,26
0,30
250
0,63
0,65
500
0,87
0,85
1000
0,62
0,70
2000
0,69
0,75
4000
0,78
0,80
NRC
0,70
aw
0,75
Sound Absorption Coefficient
1,0
0,8
0,6
0,4
0,2
5,15
OWAtecta® Rg3024
0,0
5,15
3,0
125
250
500
1000
Frequency f [Hz]
2000
4000
125
250
500
1000
Frequency f [Hz]
2000
4000
Sound Absorption
as
ap
125
0,20
0,20
250
0,57
0,60
500
0,80
0,80
1000
0,51
0,60
2000
0,63
0,65
4000
0,76
0,75
NRC
0,65
aw
0,65
OWAtecta® Qg4025
4,0
8,0
4,0
Sound Absorption Coefficient
Void Depth E200
Freq. [Hz]
1,0
0,8
0,6
0,4
0,2
0,0
8,0
Sound Absorption
Void Depth E200
Freq. [Hz]
as
ap
125
0,22
0,25
250
0,59
0,60
500
0,85
0,80
1000
0,55
0,65
2000
0,66
0,70
4000
0,78
0,80
NRC
0,65
aw
0,70
OWAtecta Sound Absorption
®
This brochure provides an overview of the sound absorption values of OWAtecta's standard perforations.
If you require any more assistance please do not hesitate to contact our acoustic specialists in the
OWAconsult® technical team.
Abidin Uygun
Thomas Plötzner
Telephone: +49 9373 20 13 61
Telephone: +49 9373 20 11 61
OWAconsult®
Hotline: +49 9373 20 12 22
Telefax: +49 9373 20 11 11
E-Mail: info@owaconsult.de
www.owaconsult.de
For more information about our metal ceiling systems please contact the OWAtecta support team.
With over sixty years experience we can help you every step of the way, from concept to design and installation
through to the finished project.
Contact:
Odenwald Faserplattenwerk GmbH
Dr.- F.-A.-Freundt-Straße 3
63916 Amorbach
Tel. +49 9373 2 01-0
Fax +49 9373 2 01-1 30
www.owa.de · E-Mail: info@owa.de
Publication No. 358 eng
051102
www.owa.de