A crack with an opening accessible to contaminants. For example a narrow opening or fissure either in the bulk of a material or between two closely fitting components, such as a flange and its gasket. Typically, a crevice has a depth more than 20 times the width of its opening. Crevices may not only harbour soils and micro-organisms and be inaccessible to cleaning agents, but may also cause accelerated corrosion of the bulk material, rapidly increasing the size of the crevice.
