2022 NAICS national industry in sector 56 Administrative and Support and Waste Management and Remediation Services
561621 Security Systems Services (except Locksmiths)
NAICS 561621 is the US industry code for security systems services (except locksmiths). This U.S.
- Code
- 561621 (2022 NAICS)
- Title
- Security Systems Services (except Locksmiths)
- Part of
- Security Systems Services
- SBA small business limit
- Average annual receipts up to $25 million
- Closest UK SIC
- 80200 (details)
Changes coming. The NAICS 2027 revision applies to data from 1 January 2027, and SBA proposed new size standards on 20 August 2026. The values on this page are the ones in force today; we update this page when the official files change.
Official definition
This U.S. industry comprises establishments primarily engaged in (1) selling security alarm systems, such as burglar and fire alarms, along with installation, repair, or monitoring services or (2) remote monitoring of electronic security alarm systems.
When to use a different code
Census classifies these close-sounding activities somewhere else. Businesses mainly engaged in:
- Selling security alarm systems for buildings, without installation, repair, or monitoring services are classified in Sector 42, Wholesale Trade, or Sector 44-45, Retail Trade.
- Installing alarm systems (e.g., fire, burglar), without selling or monitoring services are classified in Industry 238210, Electrical Contractors and Other Wiring Installation Contractors.
- Retailing motor vehicle security systems, with or without installation or repair services are classified in Industry 441330, Automotive Parts and Accessories Retailers.
Businesses that use this code
Activities listed under 561621
The Census index assigns these 8 activities to this code. If your business matches one, this is your code.
- Alarm system monitoring services
- Alarm systems sales combined with installation, repair, or monitoring services
- Burglar alarm monitoring services
- Burglar alarm sales combined with installation, repair, or monitoring services
- Fire alarm monitoring services
- Fire alarm sales combined with installation, repair, or monitoring services
- Security alarm systems sales combined with installation, repair, or monitoring services
- Security system monitoring services
SBA size standard for 561621
To count as a small business for SBA loans and federal contracts under NAICS 561621, your business (including affiliates) must not exceed $25 million in average annual receipts. Check your business.
Source: SBA table of size standards, effective March 17, 2023.
Closest UK SIC 2007 codes
There is no official one-to-one link between NAICS and UK SIC. These codes share the same international class (ISIC Rev. 4: 8020), so treat them as a starting point and check the definition.
Built from Census concordances 2022→2017 NAICS and 2017 NAICS→ISIC Rev. 4.
Similar codes to compare
Data last changed November 14, 2026. How this page is built.