4.1 The atmospheric exposure tests described in this practice will evaluate the stability of the adhesive bond only in terms of a particular natural atmosphere. Since the atmospheric conditions vary greatly from year to year, these results will not be as reproducible as those derived from laboratory aging procedures. Considerable research has shown that laboratory artificial weathering tests will not give consistently good correlation with outdoor test exposures (2, 3, 4).

1.1 This practice covers the procedure for the direct exposure of adhesive bonded joints and structures to natural atmospheric environments.

1.2 The procedure for sheltered atmospheric exposure, such as a Stevenson screen (1),2 of adhesive-bonded joints and specimens is the same except for the requirements of facing south and measurement of solar radiation.

1.3 This practice is limited to the procedure by which samples are exposed and does not cover the tests that may be used to evaluate the effects of atmospheric exposure on these adhesive-bonded joints and structures. These samples could be any one of several varieties.

1.3.1 A complete structure for test,

1.3.2 A section of a structure for test,

1.3.3 A complete structure or section with strength observations on specimens cut therefrom,

1.3.4 Test specimens themselves, or

1.3.5 Any of the above, mounted under stress.

1.4 Suitable test methods for evaluation of the effects of exposure include nondestructive qualitative or quantitative observations on the same sample at prescribed intervals, or destructive tests on separate sets of specimens in accordance with such tests as Test Method D1002.

Note 1: See Test Methods D896 and D897.

1.5 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.

1.6 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.