ASTM D6903-07(2013)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: D6903 − 07 (Reapproved 2013)
Standard Test Method for
Determination of Organic Biocide Release Rate From
Antifouling Coatings in Substitute Ocean Water
This standard is issued under the fixed designation D6903; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope ocean water are given in Appendix X1 – Appendix X3,
respectively. Other methods may be used provided that they
1.1 This test method covers the laboratory determination of
meet the appropriate criteria given in Annex A2.
the rate at which organic biocide is released from an antifoul-
ing coating exposed in substitute ocean water. The test is run 1.5 Whenthereleaserateofahighlyphotosensitiveorganic
entirely in the laboratory under controlled conditions of pH, biocide is being determined, steps must be taken to protect the
temperature, salinity, and hydrodynamics. Analytical proce- apparatus and samples from exposure to natural and artificial
dures are provided for the determination of the release rate of visible light sources. Any such requirement for these steps to
4,5-dichloro-2-n-octylisothiazolin-3-one (DCOIT), zinc and be taken for a particular biocide is indicated in Annex A2.
copper pyrithione (ZPT and CuPT), and N-cyclopropyl-N'-(1,
1.6 Thepracticallimitsforquantifyingbiocidereleaserates
1-dimethylethyl)-6-(methylthio)-1,3,5-triazine-2,4-diamine -2 -1
bythismethodarefrom4.5to500 µgcm d forDCOIT,0.36
(CDMTD).At predetermined intervals, substitute ocean water -2 -1 -2 -1
to 500 µgcm d for CuPT, 0.36 to 500 µgcm d for ZPT,
samples are analyzed for leached biocide using a suitable -2 -1
and 2.7 to 500 µgcm d for CDMTD. These ranges may be
-2 -1
analytical technique.
extended to 3.8 to 500 µgcm d for DCOIT, 0.16 to 500 µg
-2 -1 -2 -1
1.2 In cases in which the antifouling coating contains both cm d for CuPT, 0.2 to 500 µgcm d for ZPT, and 2.2 to
-2 -1
an organic biocide and a copper-based biocide, the release rate 500 µgcm d for CDMTD if the procedures described in
of copper may optionally be concurrently determined accord- Appendix X1 – Appendix X3 (as appropriate) are followed.
ing to the procedure found in Test Method D6442. The quantitation of release rates lower than these ranges will
require the use of analytical methods with lower limits of
1.3 The procedure contains the preparation steps for the
quantitation than those specified in Annex A2.
determination of the release rate of biocide in substitute ocean
water from antifouling paints including apparatus, reagents, 1.7 The results of this test method do not reflect environ-
holding tank conditions, and sampling point details. The mental biocide release rates for antifouling products, and are
procedure calls for the accurate determination of organic not suitable for direct use in the process of generating
biocide concentrations in substitute ocean water at the low µg environmental risk assessments, environmental loading
-1
L (parts per billion, ppb) level. To detect and correct for estimates, or for establishing release rate limits for regulatory
reagent impurities and allow a suitable level of analytical purposes. See also Section 4.
precision to be achieved, the analytical method to be used for
1.8 The values stated in SI units are to be regarded as the
the determination of the concentration of organic biocide in
standard. The values given in parentheses are for information
substitute ocean water must meet the acceptability criteria
only.
given in Annex A2. Where Annex A2 specifies a limit of
1.9 This standard does not purport to address all of the
quantitation(LOQ),theprocedurefordeterminingtheLOQfor
safety concerns, if any, associated with its use. It is the
the organic biocide in substitute ocean water by the analytical
responsibility of the user of this standard to establish appro-
method presented in Annex A3 is to be followed.
priate safety and health practices and determine the applica-
1.4 Suitable analytical methods that use high-performance
bility of regulatory limitations prior to use.
liquid chromatography (HPLC) for determining the concentra-
tion of DCOIT, ZPT and CuPT, and CDMTD in substitute
2. Referenced Documents
2.1 ASTM Standards:
This test method is under the jurisdiction of ASTM Committee D01 on Paint
andRelatedCoatings,Materials,andApplicationsandisthedirectresponsibilityof
Subcommittee D01.45 on Marine Coatings. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved June 1, 2013. Published June 2013. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 2007. Last previous edition approved in 2007 as D6903 – 07. DOI: Standards volumeinformation,refertothestandard’sDocumentSummarypageon
10.1520/D6903-07R13. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6903 − 07 (2013)
D1005Test Method for Measurement of Dry-Film Thick- 4.3 By comparison with published copper and organotin
4,5
ness of Organic Coatings Using Micrometers release rate data obtained either by direct measurements
D1141Practice for the Preparation of Substitute Ocean from ship hulls or release rate measurements from harbor
Water exposed panels, all data indicate that the results of this generic
D1193Specification for Reagent Water rotating-cylinder test method significantly overestimate the
D6442Test Method for Determination of Copper Release release rate of biocide when compared to release rates under
Rate From Antifouling Coatings in Substitute Ocean in-service conditions. For example, published results demon-
Water strate that this generic test method produces higher measure-
2.2 U.S. Federal Standard: mentsofcopperandorganotinreleaseratesthanfromdirectin
40 CFR 136,Appendix B, revision 1.11 situmeasurementsforthesamecoatingonin-serviceshiphulls
and harbor-exposed panels. The difference between the results
3. Summary of Test Method
of this test method and the panel and ship studies was up to a
factorofabout30basedoncopperreleaseratedataforseveral
3.1 The candidate paint system is applied to the cylindrical
4,6
commercial antifouling coatings. No direct release rate data
test specimens. The coated specimens are placed in a tank of
from ship hulls or harbor-exposed panels have been generated
substitute ocean water in which the levels of organic biocide
to-date for the biocides covered by this method. However, the
and copper (where the coating also contains a biocidal copper
-1
expectation is that the results of this test method, when
compound) are kept below 100 µgL by circulating the
compared with the direct measurements from ship hulls and
substitute ocean water through a suitable filtration system (see
harbor-exposed panels, could follow the same trend. Realistic
5.1.3).At specified intervals, each specimen is placed in 1500
estimates of the biocide release from a ship’s hull under
mL of substitute ocean water (see Section 8 for details) and
in-service conditions can only be obtained from this test
rotatedat60rpmfor1h(orless,see8.7forfurtherexplanation
method where the difference between the results obtained by
and instruction). The rate of biocide release from the paint is
this test method and the release rate of an antifouling coating
determined by measuring concentrations of the biocide in the
in service is taken into account.
substitute ocean water in the individual measuring containers.
4.4 Where the results of this test method are used in the
3.2 Annex A2 provides acceptance criteria for analytical
process of generating environmental risk assessments, for
procedures for measuring the concentration of specific organic
environmental loading estimates, or for regulatory purposes, it
biocides in substitute ocean water. Suitable methods are
is most strongly recommended that the relationship between
providedinAppendixX1–AppendixX3.Alternativemethods
laboratory release rates and actual environment inputs is taken
may be used provided that they meet the acceptance criteria
into account to allow a more accurate approximation of the
given in Annex A2.
biocide release rate from antifouling coatings under real-life
4. Significance and Use
conditions. This can be accomplished through the application
of appropriate correction factors.
4.1 This test method is designed to provide a laboratory
procedure to quantify and characterize changes in the release
5. Apparatus
rate of organic biocide from antifouling coatings that occur
during a period of immersion under specified laboratory 5.1 Sample Generation—SeeAnnexA2forguidanceonany
conditions of constant temperature, pH, salinity, and hydrody- particular materials restriction and handling requirements re-
lating to each organic biocide.
namics. Quantitative measurement of biocide release rate is
necessary to help in selection of materials, providing quality 5.1.1 Release Rate Measuring Container—A nominal 2-L
( ⁄2-gal) container made of an inert material, approximately
control, and understanding the performance mechanism.
13.5 cm (5.3 in.) in diameter and 19 cm (7.5 in.) high, is fitted
4.2 Results from this test method establish a pattern of
withthreerodsalsomadeofaninertmaterial,approximately6
biocidereleasefromanantifoulingcoatingoveraminimumof
mm (nominal ⁄4 in.) in diameter to serve as baffles. Rods shall
45 days exposure under controlled laboratory conditions.
be evenly spaced on the inside circumference of the container
Biocide release rates of antifouling paints in-service vary over
to prevent swirling of the water with the test cylinder during
thelifeofthecoatingsystemdependingontheformulationand
rotation. The rods will be secured to the container walls using
on the physical and chemical properties of the environment.
an inert adhesive. The material of construction of the release
Factors such as differences in berthing locations, operating
rate measuring container and rods for use with any particular
schedules, length of service, condition of paint film surface,
biocide shall be as specified in A2.3. When the release rate of
temperature, pH, and salinity influence the actual release rate
a photosensitive material is to be determined, the container
under environmental conditions. Results obtained using this
shall be protected from light. The requirement to protect the
test method do not reflect actual biocide release rates that will
occur in service, but provide comparisons of the release rate
characteristics of different antifouling formulations in substi- 4
Valkirs,A. O., Seligman, P. F., Haslbeck, E., and Caso, J. S., Marine Bulletin,
tute ocean water under the prescribed laboratory conditions.
Vol. 46 (2003), pp. 763–779.
Champ,M.A.andSeligman,P.F., Organotin: Environmental Fate and Effects,
Chapter 19 — Measurement and Significance of the Release Rate for Tributyltin,
AvailablefromU.S.GovernmentPrintingOfficeSuperintendentofDocuments, (1996) Chapman and Hall, pp 383–403.
732 N. Capitol St., NW, Mail Stop: SDE, Washington, DC 20401, http:// Finnie,A.A.,ImprovedEstimatesofEnvironmentalCopperReleaseRateFrom
www.access.gpo.gov. Antifouling Coatings, Biofouling, Vol. 22 (2006), pp 279–291.
D6903 − 07 (2013)
release rate container from light for any particular organic material of construction of the test cylinder (including the
biocide is indicated in A2.4. bottomend-disk)forusewithanyparticularbiocideshallbeas
specified in A2.3. It is advisable to weight the cylinder by
NOTE1—Theresultsofthistestmethodwillbeadverselyaffectedifthe
filling with water so that the unit does not have buoyancy.
biocide is strongly adsorbed or absorbed by the release rate measuring
container or the test cylinder, or both. Where the release rates of two or
NOTE 2—When coating release rates are very high, it may be desirable
moredifferentbiocidesaretobeconcurrentlydeterminedfromasingleset 2 -1
to use a 5-cm band (100-cm paint area) to avoid exceeding 200 µgL
ofmeasurements,thereleaseratemeasuringcontainer,associatedrodsand
of organic biocide in the measuring containers (see 8.7.1).
the test cylinders must all be made of a material that is inert to all of the
biocides, otherwise repeat testing (different cylinders and measuring 5.1.6 Test Cylinder Rotating Device—The device shall be
containers) for each biocide will be required.
capable of rotating the test cylinder in the release rate measur-
-1
ing container at 60 6 5 rpm (0.2 6 0.02 m s , velocity of test
5.1.2 Constant Temperature Control—This control is a
cylinder surface). No part of the rotating device shall be
means of maintaining the release rate measuring containers at
immersed in substitute ocean water.
atemperatureof25 61°Cduringtherotationperiod(see8.7).
5.1.7 pH Meter, with a suitable electrode.
5.1.3 Holding Tank—This tank is an inert plastic container
5.1.8 Appropriate Hydrometer or Salinometer.
of such dimensions so as to permit immersion of four or more
test cylinders and must be equipped with a system to circulate
5.2 Analysis of Leachate—Suitable analytical procedures
the seawater continuously in the tank through an activated
are provided for the determination of the release rate of
carbon filter and, optionally, an absorbent filter. If an absor-
4,5-dichloro-2-n-octylisothiazolin-3-one (DCOIT), zinc and
bent filter is used, regenerate the ion exchange resin following
copper pyrithione (ZPT and CuPT), and N-cyclopropyl-N'-(1,
the manufacturer’s instructions and wash the resin with sub-
1-dimethylethyl)-6-(methylthio)-1,3,5-triazine-2,4-diamine
stitute ocean water before use. The rate of water flow and the
(CDMTD). Refer to Appendix X1 – Appendix X3 for addi-
size of the filter shall be selected to maintain the concentration
tional apparatus requirements for the analysis of specific
-1
ofeachorganicbiocidebelow100 µgL (100ppb)and,when
organic biocides in which these analytical methods are to be
the coating contains a biocidal copper compound, the concen-
used.
-1
tration of copper below 100 µgL . Flow rates should be set to
obtaintwotoeightturnoversperhour.Whenthereleaserateof
6. Reagents and Materials
a photosensitive material is to be determined, the holding tank
6.1 Sample Generation:
shall be protected from light. The requirement to protect
6.1.1 Purity of Reagents—Reagent grade chemicals shall be
holding tank from light for any particular organic biocide is
used in all tests, unless otherwise indicated. It is intended that
indicated in A2.4.
all reagents conform to the specifications of the Committee on
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