REPORT ON CLEANING
for Acrylic based Sound Absorbing and Diffusing Panel Products
1. PRODUCT IDENTIFICATION
TRADE NAMES: (AS LABELED)
MANUFACTURER’s OR
DISTRIBUTOR’s NAME:
Clearsorber® Deamp
Diviewsor™
Formedffusor™
Harmonix™ K
Modviewsor™
Omniviewsor®
RPG DIFFUSOR SYSTEMS, INC.
ADDRESS:
651C COMMERCE DR.
UPPER MARLBORO, MD 20774
PHONE NUMBER:
(301)-249-0044
2. SUMMARY
Field and laboratory tests of the cleaning of acrylic based sound absorbers and diffusers
were performed. The panels can be cleaned by wiping with a damp, micro-fiber cloth.
Clear acrylic panels gave excellent cleaning results in all cases, while frosted acrylic
panels were discolored after soiling with Arizona test dust.
Dust accumulation in the micro-slits of the Clearsorber® Deamp was visible, but slit
width was not noticeably reduced.
200 cycles of cleaning did not give any recognizable wear, though some slight change in
gloss was measured. Microorganisms were not detectable on the surface after 4 months
exposure in a public bath on the Clearsorber® Deamp panels.
3. MATERIALS AND METHODS
A. Abrasion Testing
Materials were cut to size 18” x 7”, and cleaning with dry or moist microfibre cloths
were performed in a washability apparatus (Erichsen Waschbarkeits- und
Scheuerprüfgerät). 200 cycles of cleaning were performed on each material, with
microfibre cloths attached to a 2088g weights. Gloss was measured on 20 areas of each
panel before and after the cleaning test with a micro-TRI-gloss reflectometer (BYK
Gardner GmBH, Geretsried, Germany). Electrostatic charge was measured before and
RPG DIFFUSOR SYSTEMS, INC.  651-C Commerce Drive, Upper Marlboro, MD 20774 Phone 301-249-0044 Fax 301-390-3602
after each test with ACL Model 200 Electrostatic Locator (ACL International Inc, Elk
Grove, Illinois).
B. Cleanability Testing
Dust coverage percentage was measured according to INSTA 800 before and after
cleaning by use of BM Dustdetector (BM Environmental Engineering). Three different
procedures for cleaning were employed:

Wiping with dry micro-fiber cloth. Polyester/polyamide micro-fiber cloths were
washed at 60ºC in a domestic type washing machine, and dried in a tumbledryer.

Wiping with micro-fiber cloths as described in procedure 1, but used after
spin drying (1100 rpm).

Spraying with a 0,5 % solution of commercial detergent (Nilfisk Grovrent
Extra, Nilfisk, Advance, Oslo) with 5-10 % nonionic tensides as main
active ingredient, pH 10,9 in the diluted solution), and then wiping with
damp cloths as described in procedure 2.
Between cleaning, the panels were exposed in three different ways:

Horizontally, examined face upwards, for 4-6 weeks in an office or a
photocopying / printing room in Forskningsveien 3 B, Oslo. Three panels of
each material were used.

12 sets of handprints were artificially imposed on the surface, and incubated
for 7 days before cleaning.

Four panels of each material were used, Arizona test dust (ISO 12103-1) was
spread over the surface to a coverage of 10-20 % with the aid of a Swiffer
disposable cloth, following internal standard procedure of National Institute of
Technology (Lekanger, pers. corr. 2008) (fig 10-11). Three of the panels
previously used for handprints were used.
C. Field Testing
Aluminum frames were adapted to acrylic panels, and attached to window sills in
Risenga public bath with clamps. After 4 months exposure, surfaces were sampled
for microorganisms by pressing TTC Agar Dip slides (Oxoid Ltd, Basingstoke, UK)
against the surface. Microbial contamination in the slits was examined with a similar
procedure after cutting out 50 mm long pieces of the ribs between slits. After
cleaning with damp, clean micro-fiber cloths, another set of samples were taken.
Slides were incubated for 5 days at 25 ºC before visual evaluation of growth.
RPG DIFFUSOR SYSTEMS, INC.  651-C Commerce Drive, Upper Marlboro, MD 20774 Phone 301-249-0044 Fax 301-390-3602
4. RESULTS
A. Abrasion Test
Results are given in tables 4.1.1 and 4.1.2. Gloss is reported as average and standard
deviation (s.d.) of 20 measurements. Only very slight changes in gloss and visual
appearance were measured.
Acrylic panels were electrostatically charged when the protecting layer was removed
before the test, and this charge increased during cleaning with dry cloth, while the
panels in most cases was discharged during cleaning with damp cloth.
Table 4.1.1. Results from wiping with dry micro-fiber cloth.
Panel Materia Static Static Gloss, Gloss, Gloss change
l
(In
charge, charge, before after
before after
= loss)th i
F1-1
Frosted 150
1000
18,7
20,3
1,6
plastic
F1-2
Frosted 150
2000
20,1
26,3
6,2
plastic
K1-1
Clear
500
2000
107,5 107,2
(0,3)
plastic
K1-2
Clear
500
2000
105,1 107,0
1,9
plastic
Table 4.1.2. Results from wiping with damp micro-fiber cloth.
Panel Materia Static Static Gloss Gloss Gloss
charge charge ,
, after change (In
l
parenthesis
=
loss)
Frosted before after
300
50
plastic
21,2
(7,2)
F2-1
28,4
Frosted
plastic
F2-2
0
19,9
16,4
(3,5)
-50
Clear
plastic
K2-1
500
1000
101,7 104
2,3
Clear
plastic
K2-2
750
500
105,25 107,5
2,2
s.d. Visual
appearan
2,0
3,0
1,4
1,4
Unchange
d
Unchange
d
Unchange
d
Unchange
d
s.d.
Visual
appearanc
2,7
very slight
2,2
very slight
0,8
unchanged
1
unchanged
B. Cleanability Test
I. Office dust
Visually satisfactory results were achieved with both dry and damp cloths on all
three tested materials. Dry wiping resulted in some static charge in the winter period
when relative air humidity is very low. Dust removal as measured with BM Dust
Detector was satisfactory, and summarized in table 4.2.1
RPG DIFFUSOR SYSTEMS, INC.  651-C Commerce Drive, Upper Marlboro, MD 20774 Phone 301-249-0044 Fax 301-390-3602
Table 4.2.1. Results from panels in offices. Average of 3 paralles and 3 repeats.
Material
Cleaning Average Average Visual appearance after cleaning
method % dust % dust
(before) (after)
Clear acrylic
Dry
1,2
0,2
Clean, no visible wear
Clear acrylic
Damp
1,0
0,3
Clean, no visible wear
Frosted Acrylic Dry
1,1
0,5
Clean, no visible wear
Frosted Acryli Damp
1,8
0,1
Clean, no visible wear
II.
Fingerprints
Visually excellent results were achieved with both cleaning methods on clear acrylic
panels (fig 7). Results were visually satisfactory for frosted panels; however, some
residues were visible when viewing from some angles. Observations are given in
table 4.2.2.
Table 4.2.2. Results from laboratory testing with hand prints. Average of 4 paralles
before and after 3 repeats.
Material
Cleaning Visual appearance after cleaning
method
Clear acrylic
Dry
Clean, no visible wear
Clear acrylic
Damp
Clean, no visible wear
Frosted Acrylic Dry
Some residues visible
Frosted Acrylic Damp
Some residues visible
III.
Arizona Test
Visually excellent results were achieved with both cleaning methods on clear
acrylic panels. Some disfigurement was clearly visible after cleaning with both
cleaning procedures on frosted acrylic panels, even if no dust could be detected
with BM Dust detector.
Table 4.2.2. Results from laboratory testing with Arizona dust- . Average of 4
parallels before and after 3 repeats.
Material
Cleaning Average Average Visual appearance after cleaning
method % dust % dust
(before) (after)
Clear acrylic
Damp
Surface clean, no visible wear.
Visible
15,2
0,1
Clear acrylic
Rinse
Clean, no visible wear.
&
Marked coloration of
0,6
12,8
i
lit
Frosted Acrylic Damp
Heavy
discoloration of surfaces.
18,7
3,1
Frosted Acrylic Rinse &
Heavy discoloration of surfaces.
wipe
21,5
1,5
Visual inspection of the gel-tape (Dustlifters) showed that some residual dust could
be collected from the slits, but not from the disfigured surfaces .
RPG DIFFUSOR SYSTEMS, INC.  651-C Commerce Drive, Upper Marlboro, MD 20774 Phone 301-249-0044 Fax 301-390-3602
Examination of the micro-slits in Clearsorber® Deamp clearly showed deposition of
dust. For acrylic panels cleaned without detergent, particles were deposited near
the top surface, while panels cleaned with detergent showed more even distribution
of particles. When micro-slits were examined microscopically, it was not possible
to measure any decrease in slit width by this dust deposition.
IV.
Field Test
All microbiological test were negative (< 1 cfu /cm²) after 4 months of exposure
in the public bath, both before and after cleaning. The atmosphere was
sufficiently moist and corrosive to give heavy surface corrosion of the items such
as metal clamps, but no disfigurement was visible in test or reference panels. A
few particles were visible on the surface and in the slits after 4 months.
5. DISCUSSION
It has previously been shown (e.g. Nilsen & al. 2002) that hard surfaces can be cleaned
efficiently with micro-fiber cloths. This study shows that similar results were achieved with
the acrylic panels.
In normal environments, the panels can be cleaned with satisfactory results without
detergents. For hydrophobic soling such as prints from greasy fingers or traffic dust,
commercial detergents will aid the cleaning of the frosted acrylic panels, but heavy
soiling with Arizona dust left these materials visually unsatisfactory. The clear acrylic
panels could be cleaned with excellent results with a moist microfibre cloth after all the
tested contaminants.
6. REFERENCES
INSTA 800: Cleaning quality - System for the establishment and assessment of cleaning
quality. 2. ed. Standard Norway. 2006.
ISO 12103-1:1997 Road vehicles -- Test dust for filter evaluation -- Part 1: Arizona
test dust; International Organization for Standardization, 1997.
Lekanger, R. 2008: National Institute of Technology, Oslo (personal communication).
Nilsen, S.K., I. Dahl, O. Jørgensen & T. Schneider, 2002. Micro-fiber and ultra-micro-fiber
cloths, their physical characteristics, cleaning effect, abrasion on surfaces, friction, and
wear resistance. Building and Environment, 37: 1373-137.
RPG DIFFUSOR SYSTEMS, INC.  651-C Commerce Drive, Upper Marlboro, MD 20774 Phone 301-249-0044 Fax 301-390-3602