331511 — Iron Foundries
Description
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 (as defined in the official U.S. Census Bureau 2022 NAICS Manual).
Exclusions & Cross-References
- Establishments primarily engaged in manufacturing iron castings and further manufacturing them into finished
- products are classified based on the specific finished product.
Overview Facts
Legacy SIC Concordance
Trace the historical mapping chain from the 1987 Standard Industrial Classification (SIC) to the modern 2022 NAICS code format.
- SIC 3321 - Gray and Ductile Iron Foundries (via SIC1987:3321→NAICS1997:331511→2002:331511→2007:331511→2012:331511→2017:331511→2022:331511)
- SIC 3322 - Malleable Iron Foundries (via SIC1987:3322→NAICS1997:331511→2002:331511→2007:331511→2012:331511→2017:331511→2022:331511)
Suggested Product Service Codes (Advisory)
The following Product Service Codes (PSCs) are advisory suggestions aligned with this NAICS code. Note: NAICS and PSC codes map to different dimensions of procurement (industry vs. product/service). There is no official binding 1:1 crosswalk.
- PSC 3680 — Foundry Machinery, Related Equipment and Supplies.
Source: DoD DPCAP PSC Selection Tool (Ingested: 2026-06-29)
Frequently Asked Questions (FAQ)
Is NAICS code 331511 valid in 2022? ▾
Yes, 331511 is a valid 6-digit 2022 NAICS national industry code representing 'Iron Foundries' under Sector 31-33 in the official classification index.
What is the SBA size standard for NAICS code 331511? ▾
The Small Business Administration (SBA) has established a small business size standard of 1,000 employees for NAICS code 331511 (Iron Foundries), calculated based on employees.
What is the legacy SIC equivalent for NAICS 331511? ▾
According to official Census Bureau concordance tables, NAICS code 331511 (Iron Foundries) maps to legacy 1987 Standard Industrial Classification (SIC) codes: 3321 - Gray and Ductile Iron Foundries, 3322 - Malleable Iron Foundries.
Related Pages & Tools
Further regulatory reference links for NAICS code 331511:
- Sector 31-33 Directory Hub — List of related industries in the Manufacturing sector.
- SIC ↔ NAICS Crosswalk Tool — Look up mappings between legacy SIC codes and modern classifications.
- NAICS 331511 to SIC Crosswalk — Bidirectional mapping to legacy SIC codes (Iron Foundries).
- SBA Size Standards Guide — Complete rules and averaging periods for small business classifications.
- Calculating Annual Receipts Guide — Detailed worked example of revenue calculation rules.
- IRS Principal Business Activity Guide — How NAICS codes map to corporate and entity tax filings.