(a) “Porcelain enameling” means the entire process of applying a fused vitreous enamel coating to a metal basis material. Usually this includes metal preparation and coating operations.

(b) “Basis material” means the metal part or base onto which procelain enamel is applied.

(c) “Area processed” means the total basis material area exposed to processing solutions.

(d) “Area coated” means the area of basis material covered by each coating of enamel.

(e) “Coating operations” means all of the operations associated with preparation and application of the vitreous coating. Usually this includes ballmilling, slip transport, application of slip to the workpieces, cleaning and recovery of faulty parts, and firing (fusing) of the enamel coat.

(f) “Metal preparation” means any and all of the metal processing steps preparatory to applying the enamel slip. Usually this includes cleaning, pickling and applying a nickel flash or chemical coating.

(g) The term “control authority” is defined as the POTW if it has an approved pretreatment program; in the absence of such a program, the NPDES state if it has an approved pretreatment program or EPA if the State does not have an approved program.

(h) The term “precious metal” means gold, silver, or platinum group metals and the principal alloys of those metals.