Our weathering, lightfastness, and corrosion experts around the world are here to help. AAMA Voluntary Specification, Performance Requirements and Test Procedures for Superior Performing Organic Coatings on Aluminum Extrusions and Panels This specification describes test procedures and performance requirements for superior performing organic coatings applied to aluminum extrusions and panels for architectural products. ASTM C Standard Practice for Outdoor Weathering of Construction Seals and Sealants This practice describes outdoor exposure procedures used to determine the weathering durability of building construction, seals and sealants. ASTM D Standard Practice for Conducting Exterior Exposure Tests of Paints on Wood This practice covers procedures to be followed for direct exposure of house and trim paints on new, previously unpainted wood materials to the environment.
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A number in parentheses indicates the year of last reapproval. This standard has been approved for use by agencies of the Department of Defense. It is intended for use with finished articles ofcommerce as well as with all sizes and shapes of testspecimens.
It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. Referenced Documents2. Significance and Use4. The relative durability of plastics in outdooruse can be very different depending on the location of theexposure because of differences in ultraviolet UV radiation,time of wetness, temperature, pollutants, and other factors.
Itcannot be assumed, therefore, that results from one exposure ina single location will be useful for determining relativedurability in a different location. Exposures in several locationswith different climates that represent a broad range of antici-pated service conditions are recommended. Several years ofrepeat exposures are needed to get an average test result for agiven location. The results of tests conducted for less than twelvemonths will depend on the particular season of the year inwhich they begin.
Current edition approved June 1, Published July Originally approvedin Last previous edition approved in as D - DOI: United States Unless otherwise specified, position exposureracks so that they face the equator.
The angle of the exposurerack relative to the horizontal can vary depending upon theend-use conditions that are being evaluated. NOTE 4—Exposure at the latitude angle is typically used to compareexposures from different locations when solar radiation is the main factor,and temperature and moisture are not being considered. The structural members of thetest racks shall not constitute a backing to the specimens undertest unless it is used in relation to an end-use system.
Fastenersused to attach specimens to the test rack shall provide forsecure attachment but allow specimens to expand or contractwith thermal changes, moisture absorption or desorption, orplasticizer loss. Specimen holders shouldbe used to support the many sizes of specimens involved in thistesting.
The specimen holder shall not constitute a backing forthat portion of the material to be evaluated unless it is used inrelation to an end-use system.
Aluminum extruded shapes have been found to besuitable. The exposure aperture of each frameshall be of sufficient size to expose the entire test area of eachspecimen when sufficient specimens are contained. Thismethod of mounting is shown in Fig. Thespecimens are mounted in the grooves of the insulators at afixed distance of at least 11 mm from the slotted back plate. The insulators provide inert mounting while the slotted platepermits free circulation of air behind the specimen.
Test Specimens7. They may be specimens suited to the means of evaluating theeffects of weathering on a specific physical property, or theymay be larger specimens from which smaller specimens forevaluation may be cut. Exposure test specimens should beFIG. All materialsof an unknown end use application will normally be run in anunbacked condition. When conditions of use are known, thespecimen exposed will consist of the plastic material beingevaluated plus suitable backing materials to conform to pro-jected practice.
The effect of backing is highly significant andcontributes to the degradation as a function of reflectance, heatabsorption, moisture retention, etc. It shall always be used inrelation to an end-use system rather than as a standardmounting method. These file specimens shall be retained at conditionsof They shall bekept in a storage cabinet or covered with inert wrapping toexclude light exposure during the exposure period. Test Sites8. Climatological variations withinthese areas may include those represented by desert, seashore salt air , industrial locations, tropical, and subtropical regions,plus areas exhibiting a wide range in solar radiant energy.
Thearea beneath and in the vicinity of the weathering racks shouldbe typical of the ground cover in that climatological area. Indesert areas in which sand, rock or bare earth is the prevailingground cover, coarse gravel is recommended to prevent abra-sion and significant dust accretion due to wind-blown sand Note 6. The ground cover should be low-cut grass in mosttemperate, tropical, and subtropical areas. NOTE 6—Sand as a ground cover may be desirable where the abrasiveeffects of exposure to wind-blown sand is a part of the desired exposure.
Exposure Stages9. The exposure stages must be regarded asproviding only a general indication of the degree of exposure, and theresults should always be considered in terms of characteristics of theexposure site as well. NOTE 8—The results for exposure stages of less than one year willdepend on the season of the year in which the exposure was made.
Forinstance, summer exposures are generally more severe than winterexposures. Seasonal effects are averaged in exposures of several years. Aninherent limitation in solar-radiation measurements is that theydo not reflect the effects of variations in temperature andmoisture exposure, which can often be as important as solarradiation.
This is the recommendedmethod for determining exposure stages when polymer degra-dation is being evaluated. Table 1 shows typical UV radiantexposures for 12 months in subtropical and desert climates. NOTE 9—The average UV radiant exposures shown for subtropical anddesert climates are based on several years of measurement in these testenvironments. The actual yearly values may vary widely from Table 1. Specimen marking shall be inaccordance with Practice G and shall be such that there isno interference with either the exposure or the subsequenttesting.
A number in parentheses indicates the year of last reapproval. This standard has been approved for use by agencies of the Department of Defense. It is intended for use with finished articles ofcommerce as well as with all sizes and shapes of testspecimens. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. Referenced Documents2.
The relative durability of plastics in outdoor use can be very different depending on the location of the exposure because of differences in ultraviolet UV radiation, time of wetness, temperature, pollutants, and other factors. It cannot be assumed, therefore, 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 that represent a broad range of anticipated service conditions are recommended. Several years of repeat exposures are needed to get an average test result for a given location.