40 CFR § 413.51 - Specialized definitions.

---
identifier: "/us/cfr/t40/s413.51"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "40 CFR § 413.51 - Specialized definitions."
title_number: 40
title_name: "Protection of Environment"
section_number: "413.51"
section_name: "Specialized definitions."
chapter_name: "ENVIRONMENTAL PROTECTION AGENCY"
subchapter_number: "N"
subchapter_name: "EFFLUENT GUIDELINES AND STANDARDS"
part_number: "413"
part_name: "ELECTROPLATING POINT SOURCE CATEGORY"
positive_law: false
currency: "2026-04-05"
last_updated: "2026-04-05"
format_version: "1.1.0"
generator: "[email protected]"
authority: "Secs. 301, 304(g), 307, 308, 309, 402, 405, 501(a), Clean Water Act, as amended, (33 U.S.C. 1311, 1314(g), 1317, 1318, 1319, 1322, 1325 and 1341(a))."
regulatory_source: "46 FR 9467, Jan. 28, 1981, unless otherwise noted."
cfr_part: "413"
---


# 413.51 Specialized definitions.

For the purpose of this subpart;

(a) The term *sq m* (“sq ft”) shall mean the area processed expressed in square meters (square feet).

(b) The term *operation* shall mean any step in the coating process in which a basis material surface is acted upon by a process solution and which is followed by a rinse; plus the related operations of alkaline cleaning, acid pickle, and sealing, when each operation is followed by a rinse.