ASTM D4939-89(2013)
(Test Method)Standard Test Method for Subjecting Marine Antifouling Coating to Biofouling and Fluid Shear Forces in Natural Seawater
Standard Test Method for Subjecting Marine Antifouling Coating to Biofouling and Fluid Shear Forces in Natural Seawater
SIGNIFICANCE AND USE
5.1 Effective antifouling coatings are essential for the retention of speed and reduction of operating costs of ships. This test method is designed as a screening test to evaluate antifouling coating systems under conditions of hydrodynamic stress caused by water flow alternated with static exposure to a fouling environment. A dynamic test is necessary because of the increasing availability of AF coatings that are designed to ablate in service to expose a fresh antifouling surface. Because no ship is underway continually, a static exposure phase is included to give fouling microorganisms the opportunity to attach under static conditions. After an initial 30-day static exposure, alternated 30-day dynamic and static exposures are recommended as a standard cycle. The initial static exposure is selected to represent vessels coming out of drydock and sitting pierside while work is being completed. This gives the paint time to lose any remaining solvents, complete curing, absorb water, and, in general, stabilize to the in-water environment.
5.2 This test method is intended to provide a comparison with a control antifouling coating of known performance in protecting underwater portions of ships' hulls. This test method gives an indication of the performance and anticipated service life of antifouling coatings for use on seagoing vessels. However, the degree of correlation between this test method and service performance has not been determined.
SCOPE
1.1 This test method covers the determination of antifouling performance and reduction of thickness of marine antifouling (AF) coatings by erosion or ablation (see Section 3) under specified conditions of hydrodynamic shear stress in seawater alternated with static exposure in seawater. An antifouling coating system of known performance is included to serve as a control in antifouling studies.
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
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. For a specific hazards statement, see Section 8.
General Information
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Standards Content (Sample)
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Designation: D4939 − 89 (Reapproved 2013)
Standard Test Method for
Subjecting Marine Antifouling Coating to Biofouling and
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Fluid Shear Forces in Natural Seawater
This standard is issued under the fixed designation D4939; 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.
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1. Scope 2.2 U.S. Military Specifications:
MIL-P-24441 Primer, Epoxy (Formula 150, Formula Sheet
1.1 This test method covers the determination of antifouling
24441/1)
performance and reduction of thickness of marine antifouling
MIL-P-15931B Paint, Antifouling, Vinyl, Red (Formula
(AF) coatings by erosion or ablation (see Section 3) under
121/63)
specified conditions of hydrodynamic shear stress in seawater
MIL-S-22698A Steel Plate, Carbon, Structural
alternated with static exposure in seawater. An antifouling
coating system of known performance is included to serve as a
3. Terminology
control in antifouling studies.
3.1 Definitions of Terms Specific to This Standard:
1.2 The values stated in SI units are to be regarded as the
3.1.1 ablation, n—in this test method, the removal or
standard. The values given in parentheses are for information
wearing away of the outer layers of coating caused by the
only.
combined action of hydrolysis and hydrodynamic shear stress.
1.3 This standard does not purport to address all of the
This action is often, but not necessarily, achieved by the
safety concerns, if any, associated with its use. It is the
combined effects of hydrolysis and hydrodynamic shear stress.
responsibility of the user of this standard to establish appro-
3.1.2 hydrolysis, n—softening or weakening of the outer
priate safety and health practices and determine the applica-
layers, permitting the hydrodynamic shear stresses gradually to
bility of regulatory limitations prior to use. For a specific
remove them, continually exposing a fresh antifouling surface.
hazards statement, see Section 8.
3.1.3 hydrodynamic shear stress, n—the force tangential to
the surface resulting from water in contact with and flowing
2. Referenced Documents
parallel to the surface.
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2.1 ASTM Standards:
A569/A569M Specification for Steel, Carbon (0.15
4. Summary of Test Method
Maximum,Percent),Hot-RolledSheetandStripCommer-
4.1 The antifouling coatings to be tested and a control
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cial (Withdrawn 2000)
coating are applied to steel panels and exposed in natural
D1186 Test Methods for Nondestructive Measurement of
seawater at a site where the fouling rate is high. The exposure
Dry Film Thickness of Nonmagnetic Coatings Applied to
consists of alternate static and dynamic cycles of typically 30
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a Ferrous Base (Withdrawn 2006)
days each for a total length of time to be specified (such as one
D2200 Practice for Use of Pictorial Surface Preparation
or two years) or until some selected degree of fouling is
Standards and Guides for Painting Steel Surfaces
reached. The static exposure is conducted in accordance with
D3623 Test Method for Testing Antifouling Panels in Shal-
Test Method D3623 except that the panels are smaller and are
low Submergence
preformed to fit a rotating drum. The dynamic exposure
consists of subjecting the test panels to a shear stress by
rotating the drum underwater at some specified revolution rate;
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This test method is under the jurisdiction of ASTM Committee D01 on Paint
typically,thatratethatgivesaperipheralspeedof15knots(7.6
and Related Coatings, Materials, andApplications and is the direct responsibility of
m/s). See Note 1 for an example. Photographs and film
Subcommittee D01.45 on Marine Coatings.
Current edition approved June 1, 2013. Published June 2013. Originally
thickness measurements (made in accordance with Test Meth-
approved in 1989. Last previous edition approved in 2007 as D4939 – 89 (2007).
ods D1186) are taken before exposure to seawater and, along
DOI: 10.1520/D4939-89R13.
with fouling ratings, at intervals during exposure.
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For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
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the ASTM website. Available from Standardization Documents Order Desk, DODSSP, Bldg. 4,
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The last approved version of this historical standard is referenced on Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098, http://
www.astm.org. www.dodssp.daps.mil.
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D4939 − 89 (2013)
NOTE 1—Consider antifouling pa
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