Significance and Use
The procedures described in this practice are intended to aid in evaluating the performance of coatings on various metal panels including either new or rusted steel.
The relative durability of paints in outdoor exposures can be very different depending on the location of the exposure because of differences in solar radiation, time of wetness, temperature, pollutants, and other factors. Therefore, it cannot be assumed that results from one exposure in a single location will be useful for determining relative durability in a different location. Exposures in several locations with different climates which represent a broad range of anticipated service conditions are recommended.
Because of year-to-year climatological variations, results from a single exposure test cannot be used to predict the absolute rate at which a material degrades. Several years of repeat exposures are needed to get an “average” test result for a given location.
Solar radiation varies considerably as function of time of year. This can cause large differences in the apparent rate of degradation in many polymers. Comparing results for materials exposed for short periods (less than one year) is not recommended unless materials are exposed at the same time in the same location.
The Significance and Use in Practice G 7 addresses many variables to be considered in exterior exposure tests. Guide G 141 provides more information on variability in weathering testing.
1.1 This practice covers procedures to be followed for direct exposure of exterior paints and coatings to the environment when applied to metal surfaces. When originators of a weathering test have the actual exposure conducted by a separate agency, the specific conditions for the exposure of test and control specimens should be clearly defined and mutually agreed upon between all parties.
1.2 Experience indicates that the metal used as a test substrate has a significant effect upon weathering results. The purpose of this practice is to define specific steel and other metal surfaces to be used for testing in order to minimize this source of variability.
1.3 The values stated in SI units are to be regarded as the standard. The values given in parenthesis 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.
2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.
A36/A36M Specification for Carbon Structural Steel
A283/A283M Specification for Low and Intermediate Tensile Strength Carbon Steel Plates
B209 Specification for Aluminum and Aluminum-Alloy Sheet and Plate
B449 Specification for Chromates on Aluminum
D523 Test Method for Specular Gloss
D609 Practice for Preparation of Cold-Rolled Steel Panels for Testing Paint, Varnish, Conversion Coatings, and Related Coating Products
D610 Practice for Evaluating Degree of Rusting on Painted Steel Surfaces
D660 Test Method for Evaluating Degree of Checking of Exterior Paints
D661 Test Method for Evaluating Degree of Cracking of Exterior Paints
D662 Test Method for Evaluating Degree of Erosion of Exterior Paints
D714 Test Method for Evaluating Degree of Blistering of Paints
D772 Test Method for Evaluating Degree of Flaking (Scaling) of Exterior Paints
D823 Practices for Producing Films of Uniform Thickness of Paint, Varnish, and Related Products on Test Panels
D1212 Test Methods for Measurement of Wet Film Thickness of Organic Coatings
D1654 Test Method for Evaluation of Painted or Coated Specimens Subjected to Corrosive Environments
D1729 Practice for Visual Appraisal of Colors and Color Differences of Diffusely-Illuminated Opaque Materials
D1730 Practices for Preparation of Aluminum and Aluminum-Alloy Surfaces for Painting
D2200 Practice for Use of Pictorial Surface Preparation Standards and Guides for Painting Steel Surfaces
D2201 Practice for Preparation of Zinc-Coated and Zinc-Alloy-Coated Steel Panels for Testing Paint and Related Coating Products
D2244 Practice for Calculation of Color Tolerances and Color Differences from Instrumentally Measured Color Coordinates
D2616 Test Method for Evaluation of Visual Color Difference With a Gray Scale
D2803 Guide for Testing Filiform Corrosion Resistance of Organic Coatings on Metal
D3359 Test Methods for Measuring Adhesion by Tape Test
D4214 Test Methods for Evaluating the Degree of Chalking of Exterior Paint Films
D7091 Practice for Nondestructive Measurement of Dry Film Thickness of Nonmagnetic Coatings Applied to Ferrous Metals and Nonmagnetic, Nonconductive Coatings Applied to Non-Ferrous Metals
E41 Terminology Relating To Conditioning
E1347 Test Method for Color and Color-Difference Measurement by Tristimulus Colorimetry
G7 Practice for Atmospheric Environmental Exposure Testing of Nonmetallic Materials
G113 Terminology Relating to Natural and Artificial Weathering Tests of Nonmetallic Materials
G141 Guide for Addressing Variability in Exposure Testing of Nonmetallic Materials
G147 Practice for Conditioning and Handling of Nonmetallic Materials for Natural and Artificial Weathering Tests
SSPCMethod1 Test Panel Preparation Method No 1, Uncontaminated Rusted Steel SSPC Available from Society for Protective Coatings (SSPC), 40 24th St., 6th Floor, Pittsburgh, PA 15222-4656, http://www.sspc.org.
coating; durability; exposure; metal; paint; powder coating; weathering; Outdoor weathering; Substrates; Exterior exposure tests;
ICS Number Code 87.040 (Paints and varnishes)
ASTM International is a member of CrossRef.
Citing ASTM Standards
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