ASTM C756-87(2006)
(Test Method)Standard Test Method for Cleanability of Surface Finishes
Standard Test Method for Cleanability of Surface Finishes
SIGNIFICANCE AND USE
This test method was developed to guide the user in selecting a finish coating or material that is resistant to soiling in a particular application.
The numerical values derived by this test method enables the user to rank finish coatings and materials in regard to soil retention or ease of soil removal.
SCOPE
1.1 This test method covers the numerical evaluation of the ease or difficulty of cleaning soiled surface finishes. This test method is applicable to all surface finishes not affected by water.
1.2 Values given in SI units are to be regarded as the standard. Inch-pound units are provided for information only.
This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:C756–87 (Reapproved 2006)
Standard Test Method for
Cleanability of Surface Finishes
This standard is issued under the fixed designation C756; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope reference surface, while indexes less than 1.0 indicate that the
test surface is more easily cleanable than the standard of
1.1 This test method covers the numerical evaluation of the
comparison.
ease or difficulty of cleaning soiled surface finishes. This test
3.2 The soiling agent used consists of polyethylene glycol,
method is applicable to all surface finishes not affected by
a black dye, and a fluorescent tracer, each of which is readily
water.
water soluble.
1.2 Values given in SI units are to be regarded as the
standard. Inch-pound units are provided for information only.
4. Significance and Use
1.3 This standard does not purport to address all of the
4.1 This test method was developed to guide the user in
safety concerns, if any, associated with its use. It is the
selecting a finish coating or material that is resistant to soiling
responsibility of the user of this standard to establish appro-
in a particular application.
priate safety and health practices and determine the applica-
4.2 The numerical values derived by this test method
bility of regulatory limitations prior to use.
enables the user to rank finish coatings and materials in regard
2. Referenced Documents to soil retention or ease of soil removal.
2.1 ASTM Standards:
5. Apparatus
C282 Test Method for Acid Resistance of Porcelain Enam-
5.1 Motor-Driven Lapping Plate, 203-mm (8-in.) diameter,
els(Citric Acid Spot Test)
speed 163 r/min.
C614 TestMethodforAlkaliResistanceofPorcelainEnam-
5.2 Automatic Polishing Unit, 11-s cycle, adjustable to
els
48-mm (1 ⁄8-in.) stroke.
3. Summary of Test Method 5.3 Hypodermic Syringe, glass, 2-mL capacity, without
needle.
3.1 The test method consists of applying an exact amount of
5.4 Repeating Pipet, 0.025 mL (25 µl) capacity.
a fluorescent water-soluble soiling agent to a specimen surface
5.5 Repeating Pipet, 10-mL capacity.
and then cleaning the surface with a reproducible machine-
5.6 Desiccator approximately 254 mm (10 in.) diameter.
wiping technique. The soil remaining on the specimen after
5.7 Cleaning Head, brass, 57 mm (2 ⁄4 in.), with worm-
wipingisextractedwithawatersolventandthefluorescenceof
driven hose clamp for attachment of cleaning tissues (Fig. 1).
the solution measured. A standard reference surface is treated
5.8 Soiling Head, brass, 25 mm (1 in.) diameter, with
inasimilarmanner.Thecleanabilityindexofthesurfaceunder
25-mm (1-in.) diameter facing of polytetrafluoroethylene at-
testisexpressedastheratioofthefluorescenceofthesolutions
tached with a water-proof household cement (Fig. 1).
extracted from the test surface and from the standard reference
5.9 Extraction Cell, fitted with a fluorosilicone O-ring, size
surface. Cleanability indexes greater than 1.0 indicate that the
1 1
3.2 by 57 mm ( ⁄8 by 2 ⁄4 in.) (Fig. 2).
test surface is more difficult to clean than the standard
Suitable lapping plates are available from Buehler Ltd., 2120 Greenwood St.,
Evanston, IL60204, Struers, Inc., 20102 Progress Drive, Cleveland, OH, 44136; or
ThistestmethodisunderthejurisdictionofASTMCommitteeB08onMetallic other Metallurgical Supply Sources.
and Inorganic Coatings and is the direct responsibility of Subcommittee B08.12 on An Olsen “S.M.” Automatic Polisher has been found suitable and is available
Materials for Porcelain Enamel and Ceramic-Metal Systems. under the code name OLPOL from Struers, Inc., 20102 Progress Drive, Cleveland,
Current edition approved April 1, 2006. Published May 2006. Originally OH 44136.
approved in 1973. Last previous edition approved in 1999 as C756 – 87 (1999). O-rings must be fluorosilicone polymer; consult Precision Associates, 742 N.
DOI: 10.1520/C0756-87R06. Washington Ave., Minneapolis, MN 55401; Parker Seal Co., 10567 W. Jefferson
For referenced ASTM standards, visit the ASTM website, www.astm.org, or Blvd., Culver City, CA 90230; & B. W. Rogers (Parker Dis.) 1000 Brookpark Rd.,
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Cleveland, OH 44109. Also see other sources in Thomas Register under SEALS:
Standards volume information, refer to the standard’s Document Summary page on “O” RINGS.Asuitable device for clamping the cell to a specimen is shown in Fig.
the ASTM website. 3 and Fig. 5.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
C756–87 (2006)
Cleaning Head, Brass Soiling Head, Brass
Metric Equivalents
AB C D E F G H
1 5 7 3 5 3 3
in. 2 ⁄4 ⁄8 ⁄8 ⁄16 1 ⁄8 ⁄4 ⁄16
(mm) (57) (16) (22) (5) (25) (16) (19) (5)
FIG. 1 Cleaning and Soiling Heads
5.10 Fluorometer, for measuring the fluorescence of solu- between 102 and 127 mm (4 and 5 in.). Sharp or jagged edges
tions. shall be filed or honed to prevent snagging of the cleaning
5.11 0.9 Neutral Density Filter, 50.8 by 50.8 mm (2 by 2 tissues during the mechanical cleaning process.
in.) glass mounted (transmission 12.5 %).
7.2 Twelvespecimensarerequiredtoevaluatethecleanabil-
5.12 Beakers, borosilicate, 100-mL capacity.
ity index, that is, six of the candidate surface, and six of a
porcelain enamel standard reference surface for cleanability.
6. Reagents and Materials
Porcelain enamel specimens are not damaged by the cleanabil-
6.1 Cleaning Tissues, approximately 127 by 229 mm (5 by
ity test and may be cleaned and reused many times. Specimens
9 in.).
have been reused as many as 50 times without damage or solid
6.2 Potassium Carbonate.
buildup.
6.3 Polyethylene Glycol, 400.
8 NOTE 1—The porcelain enamel covercoat used to coat the standard
6.4 Uranine, water-soluble, USP.
reference surface shall have the following characteristics: Acid Resis-
6.5 Keco Acid Black, B(F101).
tance:AA(Test Method C282)Alkali Resistance: Maximum 1.55 mg/cm
6.6 Ethyl Alcohol.
wt. loss (Test Method C614).
6.7 Mild Household Detergent, liquid.
8. Preparation of Standard Soil
7. Test Specimens
8.1 The soiling agent shall consist of the following:
7.1 The preferred specimen size is 114 mm (4 ⁄2 in.) square,
Ingredient Weight %
but any other size or shape may be used provided it can be
Polyethylene glycol 98
rotated on the lapping wheel and the smaller dimension is Keco Acid Black B 1
Uranine, water-soluble 1
8.2 The uranine shall be added to the polyethylene glycol in
Turner Fluorometer, Model 111 (Turner 111-003) available from Curtin
food blender and mixed by alternate periods of mixing and
Matheson Scientific, Inc., 10727 Tucker St., Beltsville, MD 20705, Sequoia-Turner
standing until the crystalline uranine appears to be completely
Dial Model 111, Fisher Scientific Co., 711 Forbes Ave., Pittsburg, PA 15219, and
other principal cities for both.
dissolved in the glycol. The black dye which obscures all else
Cel-Fibe Wipes, Type 1745 or equivalent.
shall be added last and thoroughly mixed in the blender. This
Uranine is the sodium salt of fluorescein, C H O Na .
20 10 5 2
soiling agent shall be stored in a tightly stoppered glass bottle
Awater-soluble fabric dye used principally for nylon, silk, and wool; available
from Keystone Aniline and Chemical Co., 321 N. Loomis, Chicago, IL 60607. at least overnight before use.
C756–87 (2006)
Metric Equivalents
AB C D E F G H I
1 1 1 1 1 5 1 7 1
in. ⁄16 ⁄8 ⁄64 2 ⁄2 1 ⁄4 ⁄8 ⁄16 1 ⁄8 2 ⁄8
(mm.) (1.6) (3.2) (0.4) (64) (32) (16) (1.6) (47) (54)
All surfaces to be plated with bright nickel.
FIG. 2 Brass Extraction Cell
9. Procedure the center of each of the six specimens. Center the first
specimen on the lapping wheel and hold it in place by means
9.1 Specimen Pretreatment—Scrub the specimens with a
of adhesive tape across the specimen corners. Place the
cellulose sponge wet with a 1 % solution of a mild household
polytetrafluoroethylene-faced soiling head on the soil, and
detergent at room temperature. Rinse in turn with tap water,
engage the spindle (Fig. 4) of the polishing unit. Operate the
distilled water, and ethyl alcohol, and allow to dry in a
lapping wheel and the polishing unit for 1 min to distribute the
near-vertical position at room temperature. Store the washed
soil over the central portion of the specimen (Fig. 5). Remove
and dried specimens overnight in a desiccator charged with a
the soiling head and clean it with tissue for reuse. Adjust the
saturated solution of potassium carbonate.
spindle so that it rests over the center of the soil spot. Prepare
9.2 Conditioning of Cleaning Tissues—Cut a supply of
twocleaningheads57mm(2 ⁄4in.)diameter)bycoveringwith
tissues ample for use in specimen cleaning treatment in the
fourthicknessesofcleaningtissuesclampedsmoothlyinplace.
following paragraph into approximately 102-mm (4-in.)
With the repeating pipet expel exactly 0.021 mL of distilled
squares and store overnight, before use, in a desiccator charged
water at the center of the tissue on the first cleaning head.
with a saturated solution of potassium carbonate (relative
9.3.2 Immediately place the cleaning head with tissue side
humidity approximately 45 %). Allow the tissues to remain in
againstthesoiledspecimen,engagethespindle,andoperatefor
the desiccator until just prior to use.
22 s (so that it will stop as well as start at the center of the
9.3 Soiling and Cleaning Treatments:
specimen). Remove the cleaning head without sliding motion.
9.3.1 Lay out six specimens face up on a table. Homogenize
Repeat the cleaning operation with the second tissue-covered
thesoilingagentbyup-endingseveraltimesbeforeuse.Fillthe
head,usingthesameamountofdistilledwaterandforthesame
hypodermic syringe with no needle attached with the soiling
22-s period.
agent by withdrawing the plunger. Expel this charge of soil
back into the soil bottle. Then fill the syringe again. Wipe the 9.3.3 Store the first soiled and cleaned specimen in a near
tipofthesyringewithacleaningtissueandexpelseveraldrops vertical position in a rack while applying exactly the same
into the soil bottle. Then, without rewiping the tip, hold the series of soiling and cleaning treatments to the five remaining
syringe vertically over a specimen and discharge one drop near specimens.
C756–87 (2006)
Metric Equivalents
AB C D E F G H I J K L M N
1 1 3 1 7 5 1 1 1 5 5
in. ⁄16 2 ⁄4 1 ⁄8 ⁄4 1 ⁄8 ⁄16 56 1 ⁄4 3 ⁄4 ⁄4 4 ⁄8 4 ⁄8 5
(mm) (1.6) (64) (35) (6.4) (47) (8) (127) (152) (32) (83) (6.4) (117) (117) (127)
FIG. 3 Device for Clamping Extraction Cell to Specimen
them on scale. Redetermine the blank reading with the filter in place and
9.4 Water Extraction of the Soil Retained—Remove the
multiply the reduced reading by 8.0 which is 1 divided by the 12.5 %
small, often nonvisible, amounts of soil from the central
transmission of the neutral density filter.
portion of the soiled and cleaned specimens with 10 mL of
distilled water in the O-ring sealed extraction cell by the 9.6 Standard Reference Surface—Apply the test procedure
following sequence of operations within 30 min after soiling;
outlined in 7.1 through 7.5 to the Standard Reference Surfaces
place the first soiled and cleaned specimen, face up, in the at least once during each testing day to obtain the average
center of the cell clamping frame. Place a clean and dry
fluorescence of solutions extracted from these specimens.
extraction cell (Fig. 2) on the center of the specimen so that the 9.7 Preferred Methods of Equipment Cleaning:
O-ring defines the area to be extracted (Fig. 5). Clamp the cell 9.7.1 The successful use of the fluorimetric analytical tech-
intheframewithalightpressurefromthewingnuts;introduce
niques employed in this procedure demands that a scrupulous
10 mL of distilled water with the 10-mL repeating pipet, swirl level of cleanliness be maintained throughout. An oily thumb-
the water in the cell momentarily and let stand for 3 min, give
print on the glass cuvette containing the solution to be
the solution in the cell another swirl and pour out into a clean measured may be more fluorescent than the unknown.
and dry 100 mL beaker; transfer a portion of the extract to a
9.7.2 Wash the glass beakers and the extraction cells before
clean, dry cuvette and place the cuvette in a rack until the other and after use by brushing in a warm detergent solution; rinse
five extracts are ready for measurement in the fluorometer.
copiously with flowing tap water and then with distilled water.
9.5 MeasurementofFluorescence—Operatethefluorometer The glass beakers may be oven dried. The extraction cells,
according to the manufacturer’s instructions. Measure and
without O-ring removal, may be wiped dry with clean tissue.
record the fluorescence of a distilled water blank. Measure and Clean the syringe used for dispensing uniform amounts of soil
record in turn the fluorescence of the solutions extracted from
on the specimens immediately following use with tap water,
the specimens. distilled water and alcohol, and dry the parts with tissue. Give
the glass cuvettes used for measuring fluorescent solutions
NOTE 2—If concentrated solutions give off-scale readings, a 0.9
several rinses with tap water and then alcohol, and allow to
neutral-density filter should be inserted between the fluorescing solution
drain in an inverted position in a holding rack. Discard the
and the photomultiplier. This filter transmits only 12.5 % of the light
emitted by the solution, reducing the fluroescence readings and bringing tissue for wiping glassware and other equipment after one use.
C756–87 (2006)
Metric Equivalents
AB C
1 1
in. 10 ⁄2 ⁄4
(mm.) (254) (13) (6.4)
FIG. 4 Spindle for Polisher
FIG. 5 Equipment Used in Soiling and Cleaning Specimens
C756–87 (2006)
CI 5Ft/Fr (1)
10. Calculation of a Cleanability Index
10.1 Subtract the measured fluorescence value for the dis-
where:
tilled water blank from the measured fluorescence value for
CI = the cleanability index of the surface being tested,
each of the six test surfaces and the six standard reference
Ft = theaveragecorrectedfluorescenceofthetestsurfaces
surfaces. This will result in corrected fluorescence values for
as calculated in 10.2, and
the six test surfaces and for the six standard reference surfaces.
Fr = the average corrected fluorescence of the standard
10.2 Calculate the average of
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