For AEC firms, common NAICS codes fall under engineering services (541330) and architectural services (541310). The solicitation's NAICS code and size standard determine whether a firm qualifies as small for that opportunity, which affects set-asides and evaluation.
How NAICS codes set SBA size standards
Every NAICS code carries an SBA size standard - the ceiling below which a firm still counts as a small business for federal contracting purposes. The size standard is not one universal number. It is tied to the specific NAICS code and is measured in one of two ways: by a firm's average annual receipts over a recent period, or by its average number of employees. Which measure applies depends on the industry the code describes. Most professional service codes, including the design and engineering codes, are measured by average annual receipts, while many manufacturing and other codes are measured by employee count.
Because the measure and the threshold both vary by code, a firm can be small under one NAICS code and other than small under another. The size standard also changes over time as the SBA reviews and adjusts it, so a firm should confirm the current standard for the exact code on a given solicitation rather than relying on a number it remembers from a past pursuit.
How set-asides work
A set-aside is a solicitation that a contracting officer reserves for a defined group of firms, limiting competition to that group. The most common is the small business set-aside, open only to firms that qualify as small under the solicitation's NAICS code and size standard. Layered on top of that are socioeconomic set-asides that further narrow eligibility to firms holding a particular certification or status.
- Small business set-asides - reserved for firms that meet the size standard for the solicitation's NAICS code.
- Socioeconomic set-asides - reserved for firms in categories such as small disadvantaged businesses, women-owned small businesses, service-disabled veteran-owned small businesses, and firms located in historically underutilized business zones.
Set-aside eligibility flows directly from the NAICS code the agency assigned. A firm that is small under the chosen code and holds any required certification can compete on the set-aside. A firm that exceeds the size standard for that code cannot, even if it would qualify as small under a different code. This is one reason the code on a solicitation deserves attention early in the go or no-go decision.
Finding and selecting a firm's NAICS codes
A firm identifies the NAICS codes that describe its work by matching its services to the published NAICS structure, which the U.S. Census Bureau maintains and updates on a periodic cycle. Most firms list several codes that cover their range of services and designate one as the primary code - typically the code representing the largest share of revenue. During federal registration, the firm records these codes in its SAM.gov profile so that agencies and prime contractors can find it by capability.
The codes a firm lists in SAM.gov describe what it does; they do not by themselves establish small-business status for any single contract. Status is always evaluated against the size standard for the NAICS code the agency assigned to the specific solicitation. A firm should keep its SAM.gov codes current so that its registration reflects the services it actually offers and so it surfaces in agency market research.
Why the solicitation's chosen code matters
For any given pursuit, the NAICS code that governs is the one the contracting officer selected for that solicitation - not necessarily the firm's primary code. That single choice drives which size standard applies, whether the work is set aside and for whom, and therefore whether a particular firm is even eligible to compete. Two similar projects can carry different codes and different size standards, changing who the competition is. Reviewing the assigned code and its current size standard is a practical first step when deciding whether to pursue a solicitation and how to position a response.
Common AEC-related NAICS codes
| Code | Description |
|---|---|
| 541310 | Architectural Services |
| 541320 | Landscape Architectural Services |
| 541330 | Engineering Services |
| 541370 | Surveying and Mapping (except Geophysical) Services |
These codes describe the design disciplines that appear most often on AEC pursuits, and the code an agency assigns usually reflects the dominant discipline the work calls for. The assigned code shapes the size standard and any set-aside, so it is worth confirming before responding - just as it is worth confirming the firm's standing on other qualifiers before assembling a submission.