ASTM D6990-05(2011)
(Practice)Standard Practice for Evaluating Biofouling Resistance and Physical Performance of Marine Coating Systems (Withdrawn 2020)
Standard Practice for Evaluating Biofouling Resistance and Physical Performance of Marine Coating Systems (Withdrawn 2020)
SIGNIFICANCE AND USE
This practice is designed to provide guidance to a panel inspector for quantitative and consistent evaluation of coating performance from test panels coated with marine antifouling coating systems. The practice assesses performance of coating systems based on both antifouling and physical properties.
The user is cautioned that the results are representative for the specific region and time of year in which the specimens are immersed. It shall be noted that interpretation of results will depend on the geographical location where the test is conducted, whether the coated specimens are exposed either totally or partially immersed, under static or dynamic conditions, and position and orientation.
Simultaneous testing of a proven standard antifouling coating system (known to minimize fouling accumulation, for example, containing biocide or active agent(s) to prevent fouling settlement/growth) in the specific marine environment shall be included as a reference to assist in interpretation of results. In addition, a negative control (inert surface susceptible to heavy fouling) shall be included on a regular basis. For the exposure to be valid, the surface of the negative control should show heavy fouling relative to the standard system(s).
Marine coating systems that produce positive results relevant to the standard system(s) show potential for use in protecting underwater marine structures.
The format can be utilized independent of exposure protocol and coating type, and provides the end user with a consistent practice and format for reporting of performance rating.
SCOPE
1.1 This practice establishes a practice for evaluating degree of biofouling settlement on and physical performance of marine coating systems when panels coated with such coating systems are subjected to immersion conditions in a marine environment. Guidance for preparation or exposure and handling of test specimens can be found in related ASTM standards as noted below (see Section 2).
1.2 This practice and related exposure methodologies are designed as tools for the relative assessment of coating performance, and in no way are to be used as an absolute indicator of long-term performance under all conditions and in all environments. There can be high variability among and within exposure sites with respect to water quality and population or species of fouling organisms, and coating performance may vary with these and other properties.
1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.4 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. A specific hazard statement is given in Section 6.
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: D6990 − 05 (Reapproved 2011)
Standard Practice for
Evaluating Biofouling Resistance and Physical Performance
of Marine Coating Systems
This standard is issued under the fixed designation D6990; 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 D3623 Test Method for Testing Antifouling Panels in Shal-
low Submergence
1.1 Thispracticeestablishesapracticeforevaluatingdegree
D4938 Test Method for Erosion Testing of Antifouling
of biofouling settlement on and physical performance of
Paints Using High Velocity Water
marine coating systems when panels coated with such coating
D4939 TestMethodforSubjectingMarineAntifoulingCoat-
systems are subjected to immersion conditions in a marine
ing to Biofouling and Fluid Shear Forces in Natural
environment. Guidance for preparation or exposure and han-
Seawater
dling of test specimens can be found in related ASTM
D5479 Practice for Testing Biofouling Resistance of Marine
standards as noted below (see Section 2).
Coatings Partially Immersed
1.2 This practice and related exposure methodologies are
D5618 Test Method for Measurement of BarnacleAdhesion
designed as tools for the relative assessment of coating
Strength in Shear
performance, and in no way are to be used as an absolute
G141 Guide for Addressing Variability in Exposure Testing
indicator of long-term performance under all conditions and in
of Nonmetallic Materials
all environments. There can be high variability among and
within exposure sites with respect to water quality and popu-
3. Terminology
lation or species of fouling organisms, and coating perfor-
3.1 Definitions of Terms Specific to This Standard:
mance may vary with these and other properties.
3.1.1 biofilm, n—matrix-enclosed populations of microor-
1.3 The values stated in SI units are to be regarded as the
ganisms adherent to each other or to surfaces, or both, or
standard. The values given in parentheses are for information
interfaces.
only.
3.1.2 biofouling adhesion, n—qualitative or quantitative
1.4 This standard does not purport to address all of the
force required for the successful and complete removal of
safety concerns, if any, associated with its use. It is the
marine fouling attached to the antifouling coating surface (for
responsibility of the user of this standard to establish appro-
example, reference Test Method D5618 for barnacles).
priate safety and health practices and determine the applica-
3.1.3 corrosion eruptions, n—build up of oxides, exiting
bility of regulatory limitations prior to use. A specific hazard
through protective paint film.
statement is given in Section 6.
3.1.4 damage, n—limited destruction of portions of paint
2. Referenced Documents
film due to impact with a foreign article.
2.1 ASTM Standards:
3.1.5 digging, n—a term used to describe hard fouling
RecommendedASTM Methods and Practices for evaluation
macroorganisms that are growing “into” the coating. That is,
of antifouling coatings via panel exposure under a variety of
where its calcareous shell penetrates/breaks through the coat-
exposure conditions:
ing surface causing physical damage to the coating.
3.1.6 macroorganism, n—organismslargeenoughtobeseen
with the naked eye and thus would be noted when growing on
This practice is under the jurisdiction of ASTM Committee D01 on Paint and
submerged surfaces.
Related Coatings, Materials, and Applications and is the direct responsibility of
Subcommittee D01.45 on Marine Coatings.
3.1.7 microorganism, n—organisms too small to be seen
Current edition approved June 1, 2011. Published June 2011. Originally
with the naked eye, which generally include bacteria, protozoa,
approved in 2003. Last previous edition approved in 2005 as D6990 – 05. DOI:
fungi and microalgae (sometimes collectively called “slime”).
10.1520/D6990-05R11.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
3.1.8 peeling, n—the phenomenon manifested in paint films
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
where a portion of a film, when pulled, can be removed in
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. strips or relatively large intact pieces, or both.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6990 − 05 (2011)
3.1.9 silt, n—sedimentary material consisting especially of on contact as well as adverse physiological effects if ingested
mineral particles intermediate in size between those of sand or inhaled. In the preparation, application, and general han-
and clay. dling of panels coated with various types of marine paints, the
use of appropriate protective clothing and equipment is re-
3.1.10 softness, adv—the phenomenon manifested by paints
quired consistent with local, state, federal government regula-
in transferring some of its pigmentation to a foreign item or
tions and recognized industrial and technical standards.
substance, upon encountering friction on its surface.
3.1.11 wearing, n—gradual loss of the paint film caused by
7. Procedure—Evaluation of Fouling Present on Test
use or exposure to the environment.
Surface
4. Summary of Practice
7.1 Controls should be exposed and assessed at the same
time as the test materials. More information about the use of
4.1 Test specimens or panels are coated with marine coating
control materials in weathering tests can be found in Guide
systems and exposed to marine immersion conditions for a
G141. (See also 5.3.)
specified amount of time and under specific sets of conditions
as agreed upon by the producer and user. See 2.1 for published
7.2 Retrieve test panels and any negative controls and
ASTM standard methods and practices that provide guidance
reference coatings from immersion site. Note and record the
for exposure of coating systems.
visual percentage coverage by biofilm or silt, or both, or lack
thereof in accordance with the guidelines provided below.
4.2 Coating systems are evaluated in terms of fouling rating
(percent of coverage of the coating system by biofouling
7.3 Prior to inspection, it is recommended that panels be
organisms), and physical deterioration rating (percent area of
rinsed (see below and 7.3.2 for more information) in order to
the coating system affected by physical coating failure(s)).
remove silt (may interfere with observation of attached forms)
These data are useful in assessing and comparing effectiveness
and unattached forms. Alternatives to rinsing such as either
of antifouling coating systems.
gentle agitation of the panels or not rinsing the panels at all
may be done but must be specified in the final reports.
5. Significance and Use
Whichever preparation is chosen, it must be documented and
5.1 This practice is designed to provide guidance to a panel performed on all panels equally and at each inspection. If
inspector for quantitative and consistent evaluation of coating rinsed, the test panel surface is to be wetted using low-pressure
performance from test panels coated with marine antifouling water. For example, use household water pressures from
3 1
coating systems. The practice assesses performance of coating garden hose sized-nozzles measuring 9.5 to 13 mm ( ⁄8 to ⁄2
systems based on both antifouling and physical properties. in.) in the form of a gentle shower spray or non-forceful flow
to allow for a reliable inspection of what is attached to the
5.2 The user is cautioned that the results are representative
coating/panel.Nozzlesthatcausewatertobeforcefullyapplied
for the specific region and time of year in which the specimens
to the panel shall not be used. Warning—Risk in rinsing
areimmersed.Itshallbenotedthatinterpretationofresultswill
panels is that subsequent biofouling attachment may be af-
depend on the geographical location where the test is
fected.Alternatively, panels may be gently agitated in water to
conducted, whether the coated specimens are exposed either
remove loose/unattached bacterial biofilm or silt deposits, or
totally or partially immersed, under static or dynamic
both. Warning—Risk in not rinsing panels is that silt or slime,
conditions, and position and orientation.
or both, may interfere with assessment of biofouling attach-
5.3 Simultaneous testing of a proven standard antifouling
ment on complete panel surface.
coating system (known to minimize fouling accumulation, for
7.3.1 Test panels shall not be allowed to dry during the
example, containing biocide or active agent(s) to prevent
entire inspection period. A holding tank is useful for accom-
fouling settlement/growth) in the specific marine environment
plishing this.
shall be included as a reference to assist in interpretation of
7.3.2 Rinse water and holding tank water, shall be taken
results.Inaddition,anegativecontrol(inertsurfacesusceptible
from the immersion site.
to heavy fouling) shall be included on a regular basis. For the
7.3.3 Efforts shall be made to minimize the length of time
exposure to be valid, the surface of the negative control should
panels remain removed from the normal immersion site, and to
show heavy fouling relative to the standard system(s).
not touch the coated surfaces.
5.4 Marine coating systems that produce positive results
7.4 Populations and types of organisms will vary by test
relevant to the standard system(s) show potential for use in
site. Some examples of biofouling microorganisms include
protecting underwater marine structures.
barnacles, oysters, mussels, bryozoans (arborescent and
5.5 The format can be utilized independent of exposure
encrusting), hydroids, tubeworms, tunicates, sponges, and
protocol and coating type, and provides the end user with a
various types of algae. Each type of fouling organism directly
consistent practice and format for reporting of performance
attached to the test surface shall be reported by (1) the
rating.
estimated percentage of the panel area covered by all of the
same type of biofouling (for example, colonial forms), (2) the
6. Safety Precautions
frequency (number of individuals for the larger and solitary
6.1 Warning—Certain marine coating systems contain organisms; for example, barnacles, mussels, oysters, tube
toxicmaterials(biocides)thatmaycauseskinandeyeirritation worms, and some tunicates), and (3) the range of size for the
D6990 − 05 (2011)
individual organisms (for larger, solitary organisms). See 8.4 Observations of physical deterioration cannot be per-
Appendix X1 for guidance on estimating percent cover and formed on panel surface areas covered by hard fouling. At the
Fig. X2.1 for a suggested sample antifouling inspection report time of inspection do not count this area in the generation of
form. the physical deterioration rating (PDR); see also 11.2. At the
7.4.1 Make a note of any fouling organisms found to be end of the panel test period, a final evaluation of physical
growing into the paint film, also referred to as “digging.” deterioration rating can be performed after removal of hard
7.4.2 Note that percentage cover of algae and arborescent fouling in order to determine whether physical deterioration
bryozoansshallbebasedontheareacoveredbythe“holdfast” has occurred under areas that had been covered by hard
and not the area covered by the “strands” or colony. The type fouling.
ofalgae(forexample,brown,red,green)shallalsoberecorded
if known.
9. Procedure—Evaluation of “Softness” of Marine
7.4.3 Only attachment of primary biofouling settlement Coating System
(that is, biofouling attached directly to the coating system)
9.1 Evaluation of “softness” is intended for marine coating
shall be recorded. Notes on secondary fouling (biofouling
systems (excluding silicone coating systems), and is an indi-
attachedtootherfoulingorganisms)canbemadeifdesired,but
cator of a coating’s pigment erosion characteristics. It is
shall not factor into the generation of a “fouling rating.”
measuredonasubjectivescaleof10to0(see9.2.1),dependent
7.4.4 Percent cover by mud tube-building amphipods shall
on the amount of pigment transferred from the coating to a
bereportedasafootnoteinFig.X2.1,butshallNOTfactorinto
cotton swab.
the generation of a “fouling rating.”
9.2 After rinsing the test panels (see 7.2), rub a wet cotton
7.4.5 Partial Immersion Test Panels Only—Panels exposed
swab, exactly 10 strokes in a back and forth motion, over the
in accordance with Practice D5479 are partially immersed.The
wet test surface.The cotton swab is held at one of its ends with
non-immersed area will be subject to splash and may show
the thumb and index finger. The cotton swab is positioned at
some fouling attachment, but the area is not included in the
45° to the coating surface and sufficient pressure is applied so
determination of a fouling rating. Therefore, the fouling rating
that the cotton swab stem just starts to bend. The strokes shall
is calculated based on the fully immersed surface area, count-
be made continuously in a back and forth motion, in the same
ing the immersed surface area as 100 %.
linear pattern, approximately 50 mm (2 in.) in length. Use of
7.4.6 In addition, antifouling performance of coating sys-
proper protective equipment, such as gloves, is recommended.
tems is often different in the immediate waterline vicinity.
9.2.1 Softness shall be evaluated on the following subjec-
Therefore,anestimateofcoveragealongthefirst50mm(2in.)
tive scale, where:
of the test panel shall also be made and can then be contrasted
with the overall coverage. Fouling occurring in the “above the
10 = no pigment transferred to a cotton swab,
waterline” area, if any, is not considered when generating a
8 = trace amount of pigment transferred to a cotton swab,
“fouling rating.”
6 = slight amount of pigment transferred to a cotton swab,
7.5 Discount biofouling attachment within 13 mm ( ⁄2 in.) 4 = moderate amount of pigment transferred to a cotton
from all edges of the test panel. swab,
2 = severe amount of pigment transferred to a cotton swab,
8. Procedure—Evaluation of Physical Deterioration/
and
Performance of Test Surface
0 = complete removal of pigment transferred to a cotton
8.1 Prior to the original exposure, inspect all test panels for swab.
possible physical deterioration. Record findings. Continue
9.3 Softness measurements can be performed anywhere 13
observation of predetermined damage during future inspec-
mm ( ⁄2 in.) or more away from all edges of the test panel. In
tions. See Fig. X2.2 for a suggested sample physical perfor-
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