ASTM E822-92(2023)

2.1?In many geographic areas there is concern about the effect of falling hail upon solar collector covers. This practice may be used to determine the ability of flat-plate solar collector covers to withstand the impact forces of hailstones. In this practice, the ability of a solar collector cover plate to withstand hail impact is related to its tested ability to withstand impact from ice balls. The effects of the impact on the material are highly variable and dependent upon the material.

2.2?This practice describes a standard procedure for mounting the test specimen, conducting the impact test, and reporting the effects.

2.3?Data generated using this practice may be used: (1) to evaluate impact resistance of a single material or collector, (2) to compare the impact resistance of several materials or collectors, (3) to provide a common basis for selection of cover materials or collectors for use in various geographic areas, or (4) to evaluate changes in impact resistance due to environmental factors such as weather.

2.4?This practice does not state the size(s) of ice ball(s) to be used in making the impact. Either the person requesting the test or the person performing the test must determine ice ball size to be used in the testing. Choice of ice ball size may relate to the intent of the testing.

2.5?The hail impact resistance of materials may change as the materials are exposed to various environmental factors. This practice may be used to generate data to evaluate degradation by comparison of hail impact resistance data measured before and after exposure to such aging.

1.1?This practice covers a procedure for determining the ability of cover plates for flat-plate solar collectors to withstand impact forces of falling hail. Propelled ice balls are used to simulate falling hailstones. This practice is not intended to apply to photovoltaic cells or arrays.

1.2?This practice defines two types of test specimens, describes methods for mounting specimens, specifies impact locations on each test specimen, provides an equation for determining the velocity of any size ice ball, provides a method for impacting the test specimens with ice balls, and specifies parameters that must be recorded and reported.

1.3?This practice does not establish pass or fail levels. The determination of acceptable or unacceptable levels of ice-ball impact resistance is beyond the scope of this practice.

1.4?The size of ice ball to be used in conducting this test is not specified in this practice. This practice can be used with various sizes of ice balls.

1.5?The categories of solar collector cover plate materials to which this practice may be applied cover the range of:

1.6?Solar collector cover materials should be tested as:

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

1.8?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.

1.9?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.