ASTM D6990-03
(Practice)Standard Practice for Evaluating Biofouling Resistance and Physical Performance of Marine Coating Systems
Standard Practice for Evaluating Biofouling Resistance and Physical Performance of Marine Coating Systems
SCOPE
1.1 This method 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 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.
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Designation:D6990–03
Standard Practice for
Evaluating Biofouling Resistance and Physical Performance
of Marine Coating Systems
This standard is issued under the fixed designation D 6990; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope D 4939 Test Method for Subjecting Marine Antifouling
Coatings to Biofouling and Fluid Shear Forces in Natural
1.1 This method establishes a practice for evaluating degree
Seawater
of biofouling settlement on and physical performance of
D 5479 Practice for Testing Biofouling Resistance of Ma-
marine coating systems when panels coated with such coating
rine Coatings Partially Immersed
systems are subjected to immersion conditions in a marine
D 5618 Test Methods for Measurement of Barnacle Adhe-
environment. Guidance for preparation or exposure and han-
sion Strength in Shear
dling of test specimens can be found in related ASTM
2.2 ASTM Standards for Reference Only:
standards as noted below (see Section 2).
The followingASTM standards may provide the reader with
1.2 This practice and related exposure methodologies are
useful information on evaluating physical performance of
designed as tools for the relative assessment of coating
marine coating systems. The method references are provided
performance, and in no way are to be used as an absolute
only for the convenience of the reader. The reader is not
indicator of long-term performance under all conditions and in
required to specifically apply these methods to the ratings and
all environments. There can be high variability among and
reporting assigned under this method, but is encouraged to
within exposure sites with respect to water quality and popu-
utilizethedescriptions,definitions,andpicturesprovidedinthe
lation or species of fouling organisms, and coating perfor-
methods to assist in understanding coating physical perfor-
mance may vary with these and other properties.
mance.
1.3 This standard does not purport to address all of the
D 16 Terminology for Paint, Related Coatings, Materials,
safety concerns, if any, associated with its use. It is the
and Applications
responsibility of the user of this standard to establish appro-
D 660 Test Method for Evaluating Degree of Checking of
priate safety and health practices and determine the applica-
Exterior Paints
bility of regulatory limitations prior to use. A specific hazard
D 661 Test Method for Evaluating Degree of Cracking of
statement is given in Section 6.
Exterior Paints
2. Referenced Documents
D 662 Test Method for Evaluating Degree of Erosion of
Exterior Paints
2.1 ASTM Standards:
D 714 Test Method for Evaluating Degree of Blistering of
RecommendedASTM Methods and Practices for evaluation
Paints
of antifouling coatings via panel exposure under a variety of
D 772 Test Method for Evaluating Degree of Flaking (Scal-
exposure conditions:
ing) of Exterior Paints
D 3623 Test Method for Testing Antifouling Panels in
D 4538 Terminology Relating to Protective Coating and
Shallow Submergence
Lining Work for Power Generation Facilities
D 4938 Test Method for Erosion Testing of Antifouling
Paints Using High Velocity Water
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 biofilm, n—matrix-enclosed populations of microor-
This practice is under the jurisdiction of ASTM Committee D01 on Paint and
ganisms adherent to each other or to surfaces, or both, or
Related Coatings, Materials, and Applications and is the direct responsibility of
interfaces.
Subcommittee D01.45 on Marine Coatings.
Current edition approved Dec. 1, 2003. Published January 2004.
3.1.2 biofouling adhesion, n—qualitative force required for
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
the successful and complete removal of marine fouling at-
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
tached to the antifouling coating surface (for example, refer-
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. ence Test Methods D 5618).
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D6990–03
3.1.3 corrosion eruptions, n—build up of oxides, exiting to heavy fouling) shall be included on a regular basis. For the
through protective paint film. exposure to be valid, the surface of the negative control should
3.1.4 damage, n—limited destruction of portions of paint show heavy fouling relative to the standard system(s).
film due to impact with a foreign article. 5.4 Marine coating systems that produce positive results
3.1.5 digging, n—a term used to describe hard fouling relevant to the standard system(s) show potential for use in
macroorganisms that are growing “into” the coating. That is, protecting underwater marine structures.
where its calcareous shell penetrates/breaks through the coat- 5.5 The format can be utilized independent of exposure
ing surface causing physical damage to the coating. protocol and coating type, and provides the end user with a
3.1.6 macroorganism, n—organisms large enough to be consistent practice and format for reporting of performance
seenwiththenakedeye.Inthiscontext,theseorganismswould rating.
be noted when growing on submerged surfaces.
6. Safety Precautions
3.1.7 microorganism, n—organisms too small to be seen
6.1 Warning—Certain marine coating systems contain
with the naked eye.These generally include bacteria, protozoa,
toxicmaterials(biocides)thatmaycauseskinandeyeirritation
fungi and microalgae. Sometimes also called “slime.”
on contact as well as adverse physiological effects if ingested
3.1.8 peeling, n—the phenomenon manifested in paint films
where a portion of a film, when pulled, can be removed in or inhaled. In the preparation, application, and general han-
dling of panels coated with various types of marine paints, the
strips or relatively large intact pieces, or both.
3.1.9 silt, n—sedimentary material consisting especially of use of appropriate protective clothing and equipment is re-
quired consistent with local, state, federal government regula-
mineral particles intermediate in size between those of sand
and clay. tions and recognized industrial and technical standards.
3.1.10 softness, adj—the phenomenon manifested by paints
7. Procedure—Evaluation of Fouling Present on Test
in transferring some of its pigmentation to a foreign item or
Surface
substance, upon encountering friction on its surface.
7.1 Controls should be exposed and assessed at the same
3.1.11 wearing, n—gradual loss of the paint film caused by
time as the test materials. More information about the use of
use or exposure to the environment.
control materials in weathering tests can be found in Guide
4. Summary of Practice
G 141. (See also 5.3 above.)
7.2 Retrieve test panels and any negative controls and
4.1 Test specimens or panels are coated with marine coating
reference coatings from immersion site. Note and record the
systems and exposed to marine immersion conditions for a
visual percentage coverage by biofilm or silt, or both, or lack
specified amount of time and under specific sets of conditions
thereof in accordance with the guidelines provided below.
as agreed upon by the producer and user. See 2.1 for published
7.3 Prior to inspection, it is recommended that panels be
ASTM standard methods and practices that provide guidance
rinsed in order to remove silt (may interfere with observation
for exposure of coating systems.
of attached forms) and unattached forms. Alternatives such as
4.2 Coating systems are evaluated in terms of fouling rating
either gentle agitation of the panels or not rinsing the panels
which describes percent of coverage of the coating system by
may be done but must be specified in the final reports. (Then,
biofouling organisms, and physical deterioration rating which
check reporting section to make sure this information is
describes the percentage area of the coating system affected by
required.) Whichever preparation is chosen, it must be docu-
physical coating failure(s). These data are useful in assessing
mented and performed on all panels equally. If rinsed, the test
and comparing effectiveness of antifouling coating systems.
panel surface is to be wetted using low-pressure water (for
5. Significance and Use 3 1
example, household pressures from ⁄8 to ⁄2 in. garden hose are
5.1 This practice is designed to provide guidance to a panel sufficient) in the form of a gentle shower spray or non-forceful
inspector for quantitative and consistent evaluation of coating flow to allow for a reliable inspection of what is attached to the
performance from test panels coated with marine antifouling coating/panel.Nozzlesthatcausewatertobeforcefullyapplied
coating systems. The practice assesses performance of coating to the panel shall not be used. Warning—Risk in rinsing
systems based on both antifouling and physical properties. panels is that subsequent biofouling attachment may be af-
5.2 The user is cautioned that the results are representative fected.Alternatively, panels may be gently agitated in water to
for the specific region and time of year in which the specimens remove loose/unattached bacterial biofilm or silt deposits, or
areimmersed.Itshallbenotedthatinterpretationofresultswill both. Warning—Risk in not rinsing panels is that silt or slime,
depend on the geographical location where the test is con- or both, may interfere with assessment of biofouling attach-
ducted, whether the coated specimens are exposed either ment on complete panel surface.
totally or partially immersed, under static or dynamic condi- 7.3.1 Water used to rinse panels shall be taken from the
tions, and/or in either vertical or horizontal orientation. immersionsiteorbeofsimilarsalinitytothatoftheimmersion
5.3 Simultaneous testing of a proven standard antifouling site.
coating system (known to minimize fouling accumulation, for 7.4 Test panels shall not be allowed to dry during the entire
example, containing biocide or active agent(s) to prevent inspection period. A holding tank is useful for accomplishing
fouling settlement/growth) in the specific marine environment this.
shall be included as a reference to assist in interpretation of 7.4.1 Rise water or holding tank water, or both, shall be
results.Inaddition,anegativecontrol(inertsurfacesusceptible taken from the immersion site or be of similar salinity.
D6990–03
Immersing or rinsing biota in waters of greatly different 8.2 Evaluate individual physical performance failure, quali-
salinity may stress or kill the organisms. tatively and quantitatively, for each test specimen. Observa-
tions of erosion, wearing, blistering, alligatoring, checking,
7.4.2 Efforts shall be made to minimize the length of time
panels remain removed from the normal immersion site, and to cracking, chipping, peeling, flaking, and damage shall be
made. For additional information and guidance for evaluating
not touch the coated surfaces.
any of the previous physical deteriorations, refer to Sections 2
7.5 Populations and types of organisms will vary by test
and 3. Record the percent surface area affected by each
site. Some examples of biofouling microorganisms include
physical parameter.
barnacles, oysters, mussels, bryozoans (stalked and encrust-
8.2.1 Observations of physical deterioration shall be per-
ing), hydroids, tubeworms, tunicates, sponges, and various
formed for each coat visible to the inspector (for example,
types of algae. Each type of fouling organism directly attached
topcoat, intermediate, primer). The percent surface area af-
to the test surface shall be reported by (1) the estimated
fected by each physical parameter shall be estimated based on
percentage of the panel area covered by all of the same type of
the visible area of each coat. For example, if the panel surface
biofouling (for example, colonial forms), (2) the frequency
2 2
area is 400 cm , and the topcoat covers 300 cm , and the
(number of individuals for the larger and solitary organisms;
middle coat covers 50 cm , and the primer coat is showing
for example, barnacles, mussels, oysters, tube worms, and
through and covers the remaining 50 cm , then observations
some tunicates), and (3) the range of size for the individual
shall be made for each of these coatings.
organisms (for larger, solitary organisms). See Appendix X1
8.3 Discount any physical failures within 1 inch from all
for guidance on estimating percent cover and Fig. X2.1 for the
edges of the test panel.
suggested sample antifouling inspection report form.
7.5.1 A note shall be made if any of the fouling organisms
9. Procedure—Evaluation of “Softness” of Marine
are found to be growing into the paint film, also referred to as
Coating System
“digging.”
7.5.2 Note that percentage cover of algae and stalked
9.1 Evaluation of “softness” is intended for marine coating
bryozoansshallbebasedontheareacoveredbythe“holdfast”
systems (excluding silicone coating systems), and is an indi-
and not the area covered by the “strands” or colony. The type
cator of a coating’s pigment erosion characteristics. It is
of algae (for example, brown, red, green) or bryozoans shall
measuredonasubjectivescaleof10to0(see9.2.1),dependent
also be recorded if known.
on the amount of pigment transferred from the coating to a
7.5.3 Only attachment of primary biofouling settlement
cottonswab.Itisintendedtobeperformedafterstaticexposure
(that is, biofouling attached directly to the coating system)
only.
shall be recorded. Notes on secondary fouling (biofouling
9.2 After rinsing the test panels (see 7.2), rub a wet cotton
attachedtootherfoulingorganisms)canbemadeifdesired,but
swab, exactly 10 strokes in a back and forth motion, over the
shall not factor into the generation of a “fouling rating.”
wet test surface.The cotton swab is held at one of its ends with
7.5.4 Partial Immersion Test Panels Only—Panels exposed the thumb and index finger. The cotton swab is positioned at
in accordance with Practice D 5479 are partially immersed.
45° to the coating surface and sufficient pressure is applied so
The top 3 in. of the 6 by 18 in. test panel remain above the that the cotton swab stem just starts to bend. The strokes shall
waterline throughout the exposure period. This non-immersed
be made continuously in a back and forth motion, in the same
area (that is, the top 3 in. of the panel) will be subject to splash linear pattern, approximately 2 to 2 ⁄2 in. (50 to 65 mm) in
and may show so
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