Classes of impounding systems.

(a) For the purpose of this part, impounding systems are classified as follows:

Class 1. A system which surrounds the component served with the inner surface of the dike constructed against or within 24 inches (610 millimeters) of the component served. Class 2. A system which surrounds the component or area served with the dike located a distance away from the component or at the periphery of the area. Class 3. A system which conducts a spill by dikes and floors to a remote impounding space which does not surround the component or area served.

(b) In the case of an impounding system consisting of a combination of classes, requirements of this part regarding a single class apply according to the percentage of impoundment provided by each class.

[45 FR 9203, Feb. 11, 1980, as amended by Amdt. 193-16, 63 FR 37505, July 13, 1998]