Determination of sound absorption of office screens ...

REPORT

issued by an Accredited Testing Laboratory

Contact person RISE Date Reference Page

Geir Andresen 2020-02-28 2P01851 1 (5) Building Technology

+46 10 516 58 01

[email protected]

Scan Sørlie AS

Att: Morten Vister

Vister Grenda 80

N-1719 GREÅKER

NORGE

Determination of sound absorption of office screens according to EN-

ISO 354, SS 25269 and ISO 20189 (5 appendices)

Accred. No. 1002

Testing

ISO/IEC 17025

RISE Research Institutes of Sweden AB

Postal address Office location Phone / Fax / E-mail This report may not be reproduced other than in full, except with the prior written approval of the issuing laboratory. Box 857

SE-501 15 BORÅS Sweden

Brinellgatan 4 SE-504 62 BORÅS

+46 10 516 50 00 +46 33 13 55 02 [email protected]

Client

Scan Sørlie AS

Test object

Free standing floor screens and table screens for office purposes. Pictures of the screens and

the test set up are given in enclosure 5 in this report.

The screens were, according to labels on the packaging, provided with fabric of type Synergy

Hourglass and was tested in the following order below. The thickness of all screens was 5 cm.

The test objects are described according to information from the client. The weight and area

mass of the test objects have been measured and added to the information below.

1. Floor screen 120 cm x 155 cm. Weight and area mass: 18,4 kg / 10,1 kg/m².



4. Table screen 65 cm x 160 cm. Weight and area mass: 15,4 kg / 14,2 kg/m².

Date of test

The test objects were tested at RISE February 24 and 25, 2020. The test objects arrived SP

February 18.

Results

The results in this report are presented as equivalent sound absorption area in the one-third

octave bands 50 Hz to 5000 Hz and in the octave bands 63 Hz to 4000 Hz. The results are

summarised in the table 1 and in the appendix 1 to 4.

The measurements and the evaluations have been made according to EN ISO 354:2003 and SS

25269:2013 and RISE is accredited by Swedac for the methods.

Furthermore, the single object sound absorption coefficient, αobj,k is reported in table 2

according to SS-ISO 20189:2019.

The sound absorption coefficient is in general used for simplified 3D geometry room acoustic

modelling software to represent rooms and interior objects in order to describe their acoustic

properties. Note, that RISE is not accredited by Swedac for ISO 20189:2019 and this part is

therefore not a part of the accreditation. All results are valid for tested objects only.

REPORT

Date Reference Page

2020-02-28 2P01851 2 (5)


Equivalent sound absorption area

The equivalent sound absorption area per single object is given in m². The results are presented

in octave bands between 63 Hz to 4000 Hz. According to the standard the test result in the

octave band 63 Hz is not mandatory but is optional. It is important to be aware of the high

uncertainty in the results below 100 Hz. The results are reported with two decimals.

In the enclosures 1-4 the one-third octave bands between 50 Hz and 5000 Hz and the octave

bands between 63 Hz to 4000 Hz are presented in tabular form and in diagrams for all tested

objects.

The number of test specimens in the test room is determined by the change in the equivalent

sound absorption area of the room. The test specimen shall comprise a sufficient number of

individual object, (in general, at least three) to provide a measurable change in the equivalent

sound absorption area of the room greater than 1 m², but not more than 12 m². All tests fulfil

the test requirements.

In table 1 below the test results are summarised.

Table 1 – The equivalent sound absorption area Aobj, in m2.

Test Test objects

(Dim. in cm)

The equivalent sound absorption area per object,

(m2 Sabine) Encl.

63 Hz 125 Hz 250 Hz 500 Hz 1000 Hz 2000 Hz 4000 Hz

1

Free standing floor

screens:

120 x 155 x 5

(3 screens tested)

0,23 0,85 1,54 2,70 3,21 3,43 3,39 1

2 160 x 170 x 5 (2 screens tested)

0,47 1,10 2,18 3,86 4,34 4,49 4,41 2


0,12 0,40 0,76 1,37 1,63 1,77 1,86 3

4 Table screens:

160 x 65 x 5 (4 screens tested)

1,00 0,48 0,93 1,54 1,84 1,94 1,99 4

Determination of the object sound absorption coefficient

In table 2 the single object sound absorption coefficient in the octave band k, αobj,k, are

reported. The ratings are made according to SS-ISO 20189:2019.

In order to evaluate αobj, the total exposed surface of the smallest cuboid, S, is calculated

according to the following example in figure 1 picked up from SS-ISO 20189:2019.

The single object sound absorption coefficient in the octave bands, k, αobj,k, is defined

according to

αobj,k, = Aobj,k / S

Aobj,k is the equivalent sound absorption area in octave band.

REPORT

Date Reference Page

2020-02-28 2P01851 3 (5)


S is the total exposed surface area of the simplified acoustic representation of the single object

in the laboratory measurement for the actual mounting condition.

Weighted value is not allowed to be used according to the standard.

Figure 1. The figure show an example of calculation of the exposed surface in order to evaluate the

sound absorption coefficient according to ISO 20189

Table 2 – The single object sound absorption coefficient in octave band

Test Test objects

(Dim. in cm)

The sound absorption coefficient

63 Hz 125 Hz 250 Hz 500 Hz 1000 Hz 2000 Hz 4000 Hz

1

Free standing floor

screens:

120 x 155 x 5

(3 screens tested)

Total surface area: 12 m²

0,10 0,20 0,40 0,70 0,80 0,85 0,85


Surface area: 11,5 m² 0,10 0,20 0,40 0,65 0,75 0,80 0,75


Surface area: 13,2 m² 0,05 0,20 0,35 0,60 0,75 0,80 0,85

Table screen:

4

160 x 65 x 5

(4 screens tested)

Surface area: 9,2 m² 0,10 0,20 0,40 0,65 0,80 0,85 0,85

The results confirm high agreement of the sound absorption coefficient between the test

objects.

REPORT

Date Reference Page

2020-02-28 2P01851 4 (5)


Measurement and evaluation methods

The measurements have been carried out according to ISO 354:2003, which RISE is accredited

for. The method is valid as European standard according to EN ISO 354 and as Swedish

standard according to SS-EN ISO 354. The evaluation has been carried out according to SS

25269:2013 with regard to sound absorption. In addition the sound absorption coefficients

have been determined according to ISO 20189:2019.

The main difference between SS 25269 and ISO 20189 is that ISO opens up the possibility for

evaluation of the sound absorption coefficient compared to SS 25269 that this is restricted. The

sound absorption coefficient is in general used for simplified 3D geometry room acoustic

modelling software to represent rooms and interior objects in order to describe their acoustic

properties. Note, that evaluation according to ISO 20189:2019 is not a part of the accreditation

of this report.

The measurements have been made with 4 loudspeaker positions and 6 microphone positions

in each loudspeaker position and have giving 24 different combinations for the reverberation

time measurements. 5 decays have been used for each combination of loudspeaker and

microphone.

The absorption coefficient αs has been evaluated from:

S

2 1

= 55.3 V

c S

1

T -

1

T

where

V = Volume of the reverberation room (m³)

S = Area of the test object (m²)

c = Speed of sound in air (m/s)

c = 331 + 0.6t

t = Temperature in the air (°C)

T1 = Reverberation time of the room without test object (s)

T2 = Reverberation time of the room with test object (s)

Measurement uncertainty

From a world wide Round Robin1)

, in which SP took part, with 23 participating

laboratories from 11 countries, the following measurement uncertainty has been calculated

Frequencies (Hz) Uncertainty

100-630 ± 0,15

800-1250 ± 0,10

1600-2500 ± 0,15

3150-5000 ± 0,20

REPORT

Date Reference Page

2020-02-28 2P01851 5 (5)


1) The figures are calculated from twice the standard deviations, rounded to the nearest 0,05.

The data from the Round Robin is documented in a letter from the ASTM to the participating

laboratories.

Test room

A reverberation room with the dimensions 7,64 m x 6,16 m x 4,25 m giving the volume

200 m3 and the total surface area 211 m² was used. The suspended diffusers have been

arranged according to the Nordtest method NT ACOU 012 and SS-ISO 354.

Mounting

The office screen elements were positioned in a reverberation room as shown in enclosure 5.

They were at least 2 m apart and their distance to the nearest wall was at least 1 m.

List of instruments

Instrument Manufacturer Type Internal no

Microphone Brüel & Kjaer 4943 BX41346

Microphone Brüel & Kjaer 4943 503326





Microphone Preamplifier Brüel & Kjaer 2619 502246






Analyzer Norsonic 850 BX41346

Hygrometer/ Temperature meter Testo 605i BX80648

Programme RISE absorp 14_20180314

RISE Research Institutes of Sweden AB Building Technology - Sound and vibration

Performed by Examined by

__Signature_1 __Signature_2

Geir Andresen Dag Glebe

Appendices

REPORT

Date Reference Page

2020-02-28 2P01851 1 (2)

Appendix 1


Measurement of sound absorption area

Test Measurement of sound absorption area in a reverberation room according to

EN ISO 354 and SS 25269.

Client Scan Sørlie AS

Object Free standing floor screens

3 screens tested

Thickness: 5 cm

Panel size: 120 cm x 155 cm

Date of test February 24, 2020

Conditions Room volume: 200 m3

Temperature at measurement in the room: 20C ± 1C

Relative humidity in the room: 85 %RH ± 2 %RH

Equivalent sound absorption area per object in 1/3 octave bands (m2 Sabine)

Frequency

(Hz)

Aobj

(m²)

50 0,26

63 0,21

80 0,23

100 0,47

125 0,87

160 1,21

200 1,23

250 1,44

315 1,96

400 2,33

500 2,74

630 3,03

800 3,17

1000 3,23

1250 3,23

1600 3,41

2000 3,38

2500 3,49

3150 3,38

4000 3,36

5000 3,42

0,0

0,5

1,0

1,5

2,0

2,5

3,0

3,5

4,0

4,5

5,0

50

63

80

10

0

12

5

16

0

20

0

25

0

31

5

40

0

50

0

63

0

80

0

10

00

12

50

16

00

20

00

25

00

31

50

40

00

50

00

Equ

ival

ent

sou

nd

ab

sorp

tio

n a

rea,

m²

Frequency, Hz

REPORT

Date Reference Page

2020-02-28 2P01851 2 (2)

Appendix 1







3 screens tested

Thickness: 5 cm






Equivalent sound absorption area per object in octave bands (m2 Sabine)

Frequency

(Hz)

Aobj

(m²)

63 0,23

125 0,85

250 1,54

500 2,70

1000 3,21

2000 3,43

4000 3,39

0

0,5

1

1,5

2

2,5

3

3,5

4

4,5

5

63 125 250 500 1000 2000 4000

Equ

ival

ent

sou

nd

ab

sorp

tio

n a

rea,

m²

Frequency, Hz

REPORT

Date Reference Page

2020-02-28 2P01851 1 (2)

Appendix 2







2 screens tested

Thickness: 5 cm







Frequency

(Hz)

Aobj

(m²)

50 0,41

63 0,60

80 0,41

100 0,42

125 1,14

160 1,74

200 1,78

250 2,09

315 2,69

400 3,40

500 4,01

630 4,19

800 4,24

1000 4,34

1250 4,44

1600 4,50

2000 4,52

2500 4,46

3150 4,40

4000 4,40

5000 4,43

0,0

0,5

1,0

1,5

2,0

2,5

3,0

3,5

4,0

4,5

5,0

50

63

80

10

0

12

5

16

0

20

0

25

0

31

5

40

0

50

0

63

0

80

0

10

00

12

50

16

00

20

00

25

00

31

50

40

00

50

00

Equ

ival

ent

sou

nd

ab

sorp

tio

n a

rea,

m²

Frequency, Hz

REPORT

Date Reference Page

2020-02-28 2P01851 2 (2)

Appendix 2







2 screens tested

Thickness: 5 cm







Frequency

(Hz)

Aobj

(m²)

63 0,47

125 1,10

250 2,18

500 3,86

1000 4,34

2000 4,49

4000 4,41

0,00

0,50

1,00

1,50

2,00

2,50

3,00

3,50

4,00

4,50

5,00

63 125 250 500 1000 2000 4000

Equ

ival

ent

sou

nd

ab

sorp

tio

n a

rea,

m²

Frequency, Hz

REPORT

Date Reference Page

2020-02-28 2P01851 1 (2)

Appendix 3







6 screens tested

Thickness: 5 cm







Frequency

(Hz)

Aobj

(m²)

50 0,07

63 0,14

80 0,16

100 0,26

125 0,33

160 0,60

200 0,55

250 0,78

315 0,97

400 1,17

500 1,37

630 1,57

800 1,61

1000 1,64

1250 1,64

1600 1,75

2000 1,77

2500 1,78

3150 1,84

4000 1,82

5000 1,91

0,0

0,5

1,0

1,5

2,0

2,5

3,0

3,5

4,0

4,5

5,0

50

63

80

10

0

12

5

16

0

20

0

25

0

31

5

40

0

50

0

63

0

80

0

10

00

12

50

16

00

20

00

25

00

31

50

40

00

50

00

Equ

ival

ent

sou

nd

ab

sorp

tio

n a

rea,

m²

Frequency, Hz

REPORT

Date Reference Page

2020-02-28 2P01851 2 (2)

Appendix 3







6 screens tested

Thickness: 5 cm







Frequency

(Hz)

Aobj

(m²)

63 0,12

125 0,40

250 0,76

500 1,37

1000 1,63

2000 1,77

4000 1,86

0,00

0,50

1,00

1,50

2,00

2,50

3,00

3,50

4,00

4,50

5,00

63 125 250 500 1000 2000 4000

Equ

ival

ent

sou

nd

ab

sorp

tio

n a

rea,

m²

Frequency, Hz

REPORT

Date Reference Page

2020-02-28 2P01851 1 (2)

Appendix 4






Object Table screen

4 screens tested

Thickness: 5 cm




Temperature at measurement in the room: 20,1 C ± 1C



Frequency

(Hz)

Aobj

(m²)

50 0,26

63 0,25

80 0,24

100 0,29

125 0,52

160 0,64

200 0,89

250 0,90

315 1,01

400 1,35

500 1,55

630 1,72

800 1,85

1000 1,82

1250 1,86

1600 1,92

2000 1,93

2500 1,98

3150 2,00

4000 1,95

5000 2,01

0,0

0,5

1,0

1,5

2,0

2,5

3,0

3,5

4,0

4,5

5,0

50

63

80

10

0

12

5

16

0

20

0

25

0

31

5

40

0

50

0

63

0

80

0

10

00

12

50

16

00

20

00

25

00

31

50

40

00

50

00

Equ

ival

ent

sou

nd

ab

sorp

tio

n a

rea,

m²

Frequency, Hz

REPORT

Date Reference Page

2020-02-28 2P01851 2 (2)

Appendix 4






Object Table screen

4 screens tested

Thickness: 5 cm




Temperature at measurement in the room: 20,1 C ± 1C



Frequency

(Hz)

Aobj

(m²)

63 1,00

125 0,48

250 0,93

500 1,54

1000 1,84

2000 1,94

4000 1,99

0,00

0,50

1,00

1,50

2,00

2,50

3,00

3,50

4,00

4,50

5,00

63 125 250 500 1000 2000 4000

Equ

ival

ent

sou

nd

ab

sorp

tio

n a

rea,

m²

Frequency, Hz

REPORT

Date Reference Page

2020-02-28 2P01851 1 (2)

Appendix 5





Test 1. Free standing floor screens. 3 panels tested (120 cm x 155 cm x 5 cm) each.

Test 2. Free standing floor screens. 2 panels tested (160 cm x 170 cm x 5 cm) each.

REPORT

Date Reference Page

2020-02-28 2P01851 2 (2)

Appendix 5





Test 3. Free standing floor screens. 6 panels tested (80 cm x 125 cm x 5 cm) each

Test 4. Table screens. 4 panels tested (160 cm x 65 cm x 5 cm) each

Determination of sound absorption of office screens ...

Documents

Transcript of Determination of sound absorption of office screens ...