ASTM C1589/C1589M-18 PDF Download

ASTM C1589/C1589M-18 is a standard practice that describes outdoor exposure procedures used to evaluate the weatherability of construction seals and sealants. The weatherability of these materials can vary depending on the location and factors such as solar radiation, moisture, temperature, pollutants, and sealant color.

The standard provides three options for outdoor weathering procedures. Option 1 (Procedure A) involves exposing specimens to outdoor weathering without movement, while Option 2 (Procedure B) and Option 3 (Procedure C) incorporate cyclic movement in conjunction with weathering. Option 2 closely mimics actual movements experienced in sealant installations but is less repeatable, while Option 3 allows for excellent control and repeatability but may not fully represent movement in real-world conditions. These options were added based on scientific literature showing that applied strain during weathering affects the weatherability of sealants.

The standard emphasizes the need to consider the type, frequency, and amount of movement of sealants in different locations, as well as the importance of conducting exposures in multiple locations to represent a broad range of service conditions. It is also recommended to have control materials with known weatherability exposed alongside the test specimens for performance comparison.

The results of short-term exposure tests can provide some indication of relative outdoor performance, but they should not be used to predict the long-term performance of sealants. Multiple years of repeat exposures are necessary to establish an average test result for a given location due to climatological variations.

Furthermore, the standard recognizes that climatic and construction factors can impose cyclic movement on sealed joints, which can impact the effects of outdoor weathering and cause failures not observed without movement. The ability of sealants to withstand temperature-induced movements is therefore an essential property to evaluate.