NAICS 331524

Overview

The North American Industry Classification System (NAICS) is the federal standard for classifying business establishments to support the collection, analysis, and publication of U.S. economic statistics. Developed under the Office of Management and Budget and adopted in 1997 to replace SIC, NAICS was created jointly with Statistics Canada and Mexico’s INEGI to enable cross‑country comparability; the latest U.S. vintage in use is 2022. ¹

NAICS 331524 — Aluminum Foundries (except Die-Casting) covers establishments primarily engaged in pouring molten aluminum into molds to produce aluminum castings. Die-casting is excluded and classified under NAICS 331521; when castings are further manufactured into finished products, classification shifts to the industry of the finished item. ²

What this NAICS covers

• Production of aluminum castings by pouring molten aluminum into molds (non‑die‑casting processes). ²
• Use of purchased aluminum inputs to make castings. ²
• Foundry operations that may include cleaning and deburring of castings produced in‑house. ²
• Exclusion of aluminum die‑casting, which is classified in NAICS 331521. ²
• Exclusion of establishments that cast and then further manufacture finished products; those are classified by the finished product industry. ²

Related NAICS and PSC codes

Type	Code	Descriptor
NAICS	331521	Aluminum Die‑Casting Foundries. 2
NAICS	331525	Copper Foundries (except Die‑Casting). 2
NAICS	331528	Other Nonferrous Foundries (except Die‑Casting). 2
NAICS	331511	Iron Foundries (ferrous counterpart). 2

Small business size standard and program notes

• SBA small business size standard for NAICS 331524: 550 employees. ³
• NAICS 331524 is listed as eligible under the Women‑Owned Small Business (WOSB) Federal Contracting Program. ⁴
• Contracting officers assign a single NAICS code to each solicitation in accordance with 13 CFR 121.402; the code determines the applicable SBA size standard. ⁵

Frequently asked questions

• What activities define NAICS 331524?
  Establishments pour molten aluminum into molds to produce castings using purchased aluminum, and may clean or deburr the castings they make. Die‑casting is excluded, and further manufacturing beyond casting is classified by the finished product industry. ²

• How does NAICS 331524 differ from NAICS 331521?
  331524 covers non‑die casting (pouring molten aluminum into molds), whereas 331521 covers aluminum die‑casting performed under high pressure. They are mutually exclusive based on process. ²

• What is the SBA size standard for NAICS 331524?
  The SBA Table of Small Business Size Standards assigns 550 employees to 331524. This threshold governs “small” status for set‑asides and other programs that rely on this NAICS code. ³

• When should a requirement use 331524 versus a finished‑goods NAICS?
  If an establishment casts aluminum and then further manufactures the casting into a finished product, classification follows the industry of the finished product, not the foundry code. If only casting occurs, use 331524. ²

Useful resources

• G2X — NAICS 331524 overview
• U.S. Census Bureau: Foundries (NAICS 3315) definitions and cross‑references (includes 331524). ²
• U.S. Census Bureau: Implementation of the 2022 NAICS vintage. ⁶
• SBA: Table of Small Business Size Standards (effective March 17, 2023). ³

References

1. U.S. Census Bureau — North American Industry Classification System (NAICS) main page. https://www.census.gov/naics
2. U.S. Census Bureau — Foundries (NAICS 3315) industry definitions and cross‑references (includes 331521, 331524, 331525, 331528). https://www.census.gov/naics/resources/archives/sect31-33.html
3. U.S. Small Business Administration — Table of Small Business Size Standards (PDF, effective March 17, 2023). https://www.sba.gov/sites/default/files/2023-06/Table%20of%20Size%20Standards_Effective%20March%2017%2C%202023%20%282%29.pdf
4. U.S. Small Business Administration — Eligible NAICS for the Women‑Owned Small Business Federal Contracting Program. https://www.sba.gov/document/support-eligible-naics-women-owned-small-business-federal-contracting-program
5. U.S. Small Business Administration — Small business size standards (overview and 13 CFR 121 references). https://www.sba.gov/partners/contracting-officials/small-business-procurement/small-business-size-standards
6. U.S. Census Bureau — Implementation of the 2022 NAICS. https://www.census.gov/library/reference/code-lists/naics/2022/implementation-timeline.html