ASTM D6903-07(2013)
Standard Test Method for Determination of Organic Biocide Release Rate From Antifouling Coatings in Substitute Ocean Water

Standard No.

ASTM D6903-07(2013)

Release Date

2007

Published By

American Society for Testing and Materials (ASTM)

Status

Be replaced

Replace By

ASTM D6903-07(2020)

Latest

ASTM D6903-07(2020)

Scope

4.1 This test method is designed to provide a laboratory procedure to quantify and characterize changes in the release rate of organic biocide from antifouling coatings that occur during a period of immersion under specified laboratory conditions of constant temperature, pH, salinity, and hydrodynamics. Quantitative measurement of biocide release rate is necessary to help in selection of materials, providing quality control, and understanding the performance mechanism.

4.2 Results from this test method establish a pattern of biocide release from an antifouling coating over a minimum of 45 days exposure under controlled laboratory conditions. Biocide release rates of antifouling paints in-service vary over the life of the coating system depending on the formulation and on the physical and chemical properties of the environment. Factors such as differences in berthing locations, operating schedules, length of service, condition of paint film surface, temperature, pH, and salinity influence the actual release rate under environmental conditions. Results obtained using this 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 substitute ocean water under the prescribed laboratory conditions.

4.3 By comparison with published copper and organotin release rate data^4,5 obtained either by direct measurements from ship hulls or release rate measurements from harbor exposed panels, all data indicate that the results of this generic rotating-cylinder test method significantly overestimate the release rate of biocide when compared to release rates under in-service conditions. For example, published results demonstrate that this generic test method produces higher measurements of copper and organotin release rates than from direct in situ measurements for the same coating on in-service ship hulls and harbor-exposed panels. The difference between the results of this test method and the panel and ship studies was up to a factor of about 30 based on copper release rate data for several commercial antifouling coatings.^{4, 6} No direct release rate data from ship hulls or harbor-exposed panels have been generated to-date for the biocides covered by this method. However, the expectation is that the results of this test method, when compared with the direct measurements from ship hulls and harbor-exposed panels, could follow the same trend. Realistic estimates of the biocide release from a ship’s hull under in-service conditions can only be obtained from this test method where the difference between the results obtained by this test method and the release rate of an antifouling coating in service is taken into account.

4.4 Where the results of this test method are used in the process of generating environmental risk assessments, for environmental loading estimates, or for regulatory purposes, it is most strongly recommended that the relationship between laboratory release rates and actual environment inputs is taken into account to allow a more accurate approximation of the biocide release rate from antifouling coatings under real-life conditions. This can be accomplished through the application of appropriate correction factors.

ASTM D6903-07(2013) Referenced Document

• ASTM D1005 Standard Test Method for Measurement of Dry-Film Thickness of Organic Coatings Using Micrometers
• ASTM D1141 Standard Practice for the Preparation of Substitute Ocean Water
• ASTM D1193 Standard Specification for Reagent Water
• ASTM D6442 Standard Test Method for Copper Release Rates of Antifouling Coating Systems in Seawater

ASTM D6903-07(2013) history

• 2020 ASTM D6903-07(2020) Standard Test Method for Determination of Organic Biocide Release Rate From Antifouling Coatings in Substitute Ocean Water
• 2007 ASTM D6903-07(2013) Standard Test Method for Determination of Organic Biocide Release Rate From Antifouling Coatings in Substitute Ocean Water
• 2007 ASTM D6903-07 Standard Test Method for Determination of Organic Biocide Release Rate From Antifouling Coatings in Substitute Ocean Water