Signification et utilisation
5.1 This test procedure is used to simulate the physical and environmental stresses exposed to coatings for external transportation applications, such as automobiles, in subtropical climates, such as South Florida. It has been found that this subtropical climate leads to particularly severe deterioration of this coating. In addition to high doses of solar radiation, the prolonged water exposure and wet/dry cycles found in southern Florida are particularly important for this deterioration (3). This method was developed to address the shortcomings of historical experiments for transporting coatings, especially automotive coatings (4).

Note 1: This test program was developed through eight years of collaborative testing between automotive and aerospace Oems, material suppliers, and test equipment manufacturers. For published papers on this research, see References.

ASTM D7869-2017 Pratique standard pour les tests d'exposition à l'arc au xénon pour une exposition améliorée à la lumière et à l'eau pour les revêtements de transport

Étape 1: Portée
1.1 This practice specifies operating procedures for controlled irradiance xenon arc lamps and water equipment. The program uses one or more lamps and filters to produce irradiance similar to that of sunlight in the UV and visible range. It also simulates the water absorption and stress cycles experienced by automotive exterior coatings under natural weathering conditions. This practice has also been found to apply to coatings on other transport vehicles, such as aircraft, trucks and rail vehicles.

1.2 This practice uses a xenon arc source with a specified optical filter. The spectral power distribution (SPD) of lamps and special daylight filters is specified in Annex A1. The irradiance level used in this practice varies between 0.40 and 0.80W/(m 2 ·nm) at 340nm. Water is sprayed on the sample during parts of several dark steps. Water is applied so that the coating will absorb and desorption a large amount of water during the test. En outre, the cycle between wet/dry and warm/cold will cause mechanical stress on the material. These test conditions are designed to simulate physical and chemical stresses in subtropical climates, such as South Florida.

1.3 Les valeurs exprimées en unités SI doivent être considérées comme des valeurs standard. Aucune autre unité de mesure n'est incluse dans cette norme.

1.4 Cette norme n'est pas destinée à répondre à tous les problèmes de sécurité, si seulement, associé à son utilisation. Il est de la responsabilité des utilisateurs de cette norme d'établir des pratiques de sécurité et de santé appropriées et de déterminer l'applicabilité des restrictions réglementaires avant utilisation..