This test method is a standard procedure for determining air leakage characteristics under specified air pressure differences.
Note 18212;The air pressure differences acting across a building envelope vary greatly. The slope of the roof and other factors affecting air pressure differences and the implications of the resulting air leakage relative to the environment within buildings are discussed in the literature. , , These factors shall be considered fully when specifying the test pressure difference to be used.
Note 28212;When applying the results of tests by this test method, note that the performance of a roof or its components, or both, may be a function of proper installation and adjustment. The performance in service will also depend on the rigidity of supporting construction, the presence of interior treatments, the roof slope, and the resistance of components to deterioration by various causes: corrosive atmospheres, aging, ice, vibration, thermal expansion, and contraction, etc. It is difficult to simulate the identical complex environmental conditions that can be encountered in service, including rapidly changing pressures due to wind gusting. Some designs are more sensitive than others to these environmental conditions.
Rates of air leakage are sometimes used for comparison purposes. The comparisons are not always valid unless the components being tested and compared are of essentially the same size, configuration, and design.
Note 38212;The specimen construction discussed in 1.2 and required in 8.1 isolates a source of leakage. The rate of air leakage measured during the test method has units of cubic feet per minute per square foot (litres per second per square metre). Openings and details such as end laps or roof curbs are excluded since leakage is measured more appropriately in cubic feet per minute per foot (litres per second per metre) at these conditions. The test specimen area is relatively small; the inclusion of details will give unrealistic import to the detail''s presence when compared to actual roof constructions. This test method shall not be relied on singularly to form conclusions about overall air leakage through metal roofs. A roof contains many details. Although prescribed modifications are outside the scope of this test method, an experienced testing engineer is able to use the principles presented in the test method and to generate significant data by isolating specific details and measuring leakage.
Additional leakage sources are introduced if details are included. If total leakage is then measured, the results will generally be conservative relative to tests without details. To minimize the number of tests, the specifier may allow details such as end laps when qualitative or general quantitative results are desired and the isolation of sources is not required for performance. Only one panel end lap shall be allowed. The user shall be aware of the bias when comparing alternate systems if end laps are included.
Note 48212;This is a test procedure. It is the responsibility of the specifying agency to determine the specimen construction, size, and test pressures after considering the test methods'' guidelines. Practical considerations suggest that every combination of panel thickness, span, and design load need not be tested in order to substantiate product performance.
1.1 This test method covers the determination of the resistance of exterior metal roof panel systems to air infiltration resulting from either positive or negative air pressure differences. The test method described is for tests with constant temperature and humidity across the specimen. This test method is a spec......
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