Significance and Use
4.1 Tests conducted in accordance with this practice are used to evaluate the weatherability of construction seals and sealant materials when they are exposed to outdoor weather conditions. The weatherability of seals and sealants in actual outdoor use can be very different depending on the location, because of differences in solar radiation, moisture, temperature, pollutants, and other factors. Sealant color may also affect weatherability.
4.2 The type, frequency and amount of movement of sealants varies with location and may affect weatherability. It cannot be assumed, therefore, that results from one exposure in a single location will be useful for determining weatherability in a different location. Exposures in several locations with different climates (for example, solar radiation, moisture, temperature, pollutants, biological and other factors) that represent a broad range of anticipated service conditions are recommended.
4.3 It is strongly recommended that control materials of similar composition and construction to the test specimens and with known weatherability be exposed along with the test specimens for the purpose of comparing the performance of test materials to the controls. It is preferable to use two control materials, one with relatively good weatherability and one with relatively poor weatherability.
4.4 The results of short-term exposure tests can provide an indication of relative outdoor performance, but they shall not be used to predict the absolute long-term performance of a seal or sealant material. The results of tests conducted for less than 12 months will depend on the particular season of the year in which they begin.
4.5 Because of year-to-year climatatological variations, results from a single exposure test cannot be used to predict the absolute rate at which a seal or sealant degrades. Several years of repeat exposures are needed to determine an average test result for a given location.
4.6 Climatic and construction factors can impose cyclic movement upon sealed joints in use. This movement can impact the effects of outdoor weathering and often causes types of failure that are not produced by weathering without movement. Thus, the ability of building joint sealants to withstand temperature-induced movements of compression and expansion is an important property.
4.7 Outdoor weathering of specimens in combination with natural or forced cyclic movement during exposure can provide a more realistic assessment of the ability of a seal or sealant to withstand the combined effects of climate and movement encountered by seals and sealants in building construction applications.
Scope
1.1 This practice describes outdoor exposure procedures to be used as part of a test designed to determine the weatherability of building construction, seals and sealants.
1.2 This practice includes three procedures for outdoor weathering. Procedure A exposes specimens to outdoor weathering without movement. Procedure B and Procedure C are, respectively, continuous natural and periodic manual techniques for subjecting specimens to the combination of cyclic movement and exposure to outdoor weathering.
1.3 This practice is limited to the method by which the construction seals or sealants are exposed to outdoor weathering as part of a test program. It refers to the types of evaluations to be performed following the outdoor exposure but does not describe the test methods.
1.4 Means of evaluation of the effects of weathering will depend on the intended use of the test material.
1.5 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.
