Significance and Use
The rain spray test described in 8.1 as Method A is based upon Test Method E 331 which is intended for use in the evaluation of exterior windows, curtain walls, and doors. This test method is intended to supplement the water spray test in Practice E 823 that does not include the effects of wind-driven rain. This method includes the use of a pressure differential to enhance the penetration of water into the assembly being tested. This type of pressure differential can occur with many types of solar collector mounting configurations. In the case of solar collectors that form a building element, for example, a roof, this pressure differential will be caused by differences of pressure inside and outside the building. In the case of solar collectors mounted on standoffs or racks, this pressure differential will be caused by positive and negative wind forces acting simultaneously on faces of the collector.
Water leakage due to joint expansion can be influenced by several factors, including: the specific collector design and materials used, the test specimen temperature, and the water spray temperature (Note 1), in addition to the pressure differential. The temperature conditions will vary in outdoor exposure. The test temperatures should be selected to be representative of outdoor conditions where the collectors will be used.
Note 1—Water spray temperatures are likely to range from 4.5°C to 29.4°C (40 to 85°F).
Scope
1.1 This test method covers the determination of the resistance of flat plate solar collectors to water penetration when water is applied to their outer surfaces with a static air pressure at the outer surface higher than the pressure at the interior of the collector.
1.2 This test method is applicable to any flat plate solar collector.
1.3 The proper use of this test method requires a knowledge of the principles of pressure and deflection measurement.
1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.5 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 and health practices and determine the applicability of regulatory limitations prior to use. Specific precautionary information is contained in Section 6.