• a. Ground the test item and facility to avoid buildup of an electrostatic charge. Verify resistance/continuity in accordance with applicable safety requirements for the materiel. Employ a data collection system to measure the test volume conditions (see Part One, paragraph 5.18). Except for gaseous nitrogen (GN₂), achieve dehumidification, heating and cooling of the air envelope surrounding the test item by methods that do not change the chemical composition of the air, dust, and water vapor within the chamber test volume air.
• b. Use a test facility that consists of a chamber and accessories to control dust concentration, velocity, temperature, and humidity of dust-laden air. Ensure that the dust is uniformly distributed in the air stream. In order to provide adequate circulation of the dust-laden air, use a test chamber of sufficient size that no more than 50 percent of the test chamber's cross-sectional area (normal to airflow) and 30 percent of the volume of the test chamber is be occupied by the test item(s). Maintain and verify the concentration of dust in circulation within the chamber with suitable instrumentation such as a calibrated smoke meter and standard light source. When using this method ensure that the light source and smoke meter are kept free of dust accumulations and lens abrasion, use of a dry air purge system is a common methodology. Introduce the dust-laden air into the test space in such a manner as to allow the air to become as close to laminar as possible, but at least in a manner that prevents excessive turbulence as the flow of dust-laden air strikes the test item.
• c. Use dust in this test as outlined in paragraph 4.1.1.4 above.