The dust test is used to ascertain the ability of fiber optic components to resist the effects of a dry dust (fine sand) laden atmosphere. This test simulates the effect of sharp edged dust (fine sand) particles, up to 150 µm in size, which may penetrate into cracks, crevices and joints. This test is applicable to all optical devices and to combinations of optical devices and mechanical, electrical, electronic, electrochemical, or electromechanical devices for which exposure to the effects of a dry dust (fine sand) laden atmosphere is anticipated.

General effects resulting from the penetration of dust can include a variety of damage such as fouling of moving parts, formation of electrically conductive bridges with resulting shorts, scratching of the optical surfaces of the fiber interfaces, and acting as a nucleus for collection of water vapor and, hence, a source of possible corrosion and malfunction of equipment.