40 CFR § 413.61 - Specialized definitions.

---
identifier: "/us/cfr/t40/s413.61"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "40 CFR § 413.61 - Specialized definitions."
title_number: 40
title_name: "Protection of Environment"
section_number: "413.61"
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: "2026-03-24"
last_updated: "2026-03-24"
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"
---


# 413.61 Specialized definitions.

For the purpose of this subpart:

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

(b) The term *operation* shall mean any step in the chemical milling or etching processes in which metal is chemically or electrochemically removed from the work piece and which is followed by a rinse; this includes related metal cleaning operations which preceded chemical milling or etching, when each operation is followed by a rinse.