NAICS 321992

Overview

The North American Industry Classification System (NAICS) is the federal statistical standard for classifying business establishments to collect, analyze, and publish U.S. economic data. Developed under the Office of Management and Budget and adopted in 1997 to replace SIC, it was created jointly with Canada and Mexico to enable cross-country comparability. ¹

NAICS 321992 covers establishments primarily engaged in manufacturing prefabricated wood buildings and the wood sections and panels used to assemble such buildings. Fabricating wood buildings or wood sections/panels at the construction site belongs in Sector 23 (Construction), and making manufactured (mobile) homes is classified under 321991. ²

What this NAICS covers

• Manufacturing prefabricated wood buildings in factory settings for later installation. ²
• Producing wood sections and panelized components for prefabricated wood buildings. ²
• Assembling wood building modules and subassemblies prior to shipment. ²
• Manufacturing wall, floor, or roof panels of wood intended for prefabricated structures. ²
• Delivering factory-made wood building units/components for construction by others (manufacturing scope only). ²
• Prefabricated wood buildings not equipped with wheels (i.e., not mobile/manufactured homes). ²

Related NAICS and PSC codes

Type	Code	Descriptor
NAICS	321991	Manufactured Home (Mobile Home) Manufacturing
NAICS	332311	Prefabricated Metal Building and Component Manufacturing
PSC	5410	Prefabricated and Portable Buildings
PSC	5450	Miscellaneous Prefabricated Structures

Key exclusions and boundary with construction

• On-site fabrication of wood buildings or sections/panels is classified in Sector 23 (Construction), not in 321992. ²
• Manufactured (mobile) homes, even if primarily wood, fall under 321991 rather than 321992. ²
• Prefabricated buildings made primarily of metal are classified in 332311, not 321992. ²

Small business size standard (SBA)

• The SBA small business size standard for 321992 is 500 employees (employee-based standard). ⁴

NAICS 2022 vintage and federal data use

• Census began disseminating data on a 2022 NAICS basis with 2022 Economic Census releases, with full program adoption planned by the end of calendar year 2027 (some exceptions adopt later). ⁵

Frequently asked questions

• What activities are classified under NAICS 321992? Establishments that manufacture prefabricated wood buildings and the wood sections/panels used to assemble them. Work performed on a construction site is out of scope, and manufactured homes are classified elsewhere. ²

• How does NAICS 321992 differ from 321991? 321992 covers factory-made prefabricated wood buildings and components, excluding units on wheels. 321991 covers manufactured (mobile) homes designed to accept utility connections and not intended for regular highway movement. ²

• What is the difference between NAICS 321992 and 332311? Material drives the distinction: 321992 is for prefabricated wood buildings and wood panels/sections, while 332311 is for prefabricated metal buildings, panels, and sections. ²

• Which PSC codes commonly align with prefabricated building buys? PSC 5410 (Prefabricated and Portable Buildings) and PSC 5450 (Miscellaneous Prefabricated Structures) are frequently used when the government procures prefabricated building products. The specific PSC depends on the item being purchased. ³

• What is the SBA small business size standard for NAICS 321992? SBA sets the size standard for this manufacturing industry at 500 employees. The SBA Table of Small Business Size Standards provides the official values and effective dates used in federal procurement. ⁴

Useful resources

• U.S. Census Bureau NAICS 321992 definition and cross-references. ²
• 2017 NAICS Manual (official overview and development under OMB). ¹
• SBA Table of Small Business Size Standards (effective March 17, 2023). ⁴
• Census 2022 NAICS implementation timeline. ⁵
• PSC Manual (product and service codes and definitions). ³

References

1. U.S. Census Bureau, 2017 North American Industry Classification System (NAICS) Manual. https://www.census.gov/library/publications/2017/econ/2017-naics-manual.html
2. U.S. Census Bureau, NAICS 2022 Code 321992 – Prefabricated Wood Building Manufacturing. https://www.census.gov/naics/?input=321992&year=2022&details=321992
3. General Services Administration, Product and Service Code (PSC) Manual (April 2025). https://www.acquisition.gov/psc-manual
4. U.S. Small Business Administration, Table of Small Business Size Standards (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
5. U.S. Census Bureau, Implementation of the 2022 NAICS (timeline and program adoption). https://www.census.gov/library/reference/code-lists/naics/2022/implementation-timeline.html