NAICS Code 331511 — Iron Foundries

National Industry in the official 2022 North American Industry Classification System (U.S. Census Bureau). It is one of 3 national industries under 33151 (Ferrous Metal Foundries).

Code	331511
Title	Iron Foundries
Level	National Industry (6-digit)
Edition	NAICS 2022 edition
SBA size standard	1,000 employees

Official definition (2022 NAICS)

This U.S. industry comprises establishments primarily engaged in pouring molten pig iron or iron alloys into molds to manufacture castings (e.g., cast iron manhole covers, cast iron pipe, cast iron skillets). Establishments in this industry purchase iron made in other establishments.

Cross-References.

Is a business under 331511 "small"?

Under the SBA size standards (13 CFR 121.201, effective March 17, 2023), a business classified in NAICS 331511 qualifies as a small business if it does not exceed 1,000 employees. Small-business status determines eligibility for federal set-aside contracts, SAM.gov certifications and SBA loan programs — employee count is averaged over the latest 24 months.

Where 331511 sits in the hierarchy

Level	Code	Title
Sector	31-33	Manufacturing
Subsector	331	Primary Metal Manufacturing
Industry Group	3315	Foundries
NAICS Industry	33151	Ferrous Metal Foundries
National Industry	331511	Iron Foundries

Related SIC codes

Via the official U.S. Census concordance (1987 SIC ↔ NAICS), shown only where the industry definition is unchanged in NAICS 2022.

SIC code	Title
3321	Gray and Ductile Iron Foundries
3322	Malleable Iron Foundries

Related National Industry codes

• 331512 — Steel Investment Foundries
• 331513 — Steel Foundries (except Investment)

Data: official 2022 NAICS structure, descriptions and Census concordances, U.S. Census Bureau — U.S. government works in the public domain (17 U.S.C. §105). Suggested reference, not an official determination.