What is the SBA size standard for NAICS 561621?

The SBA size standard for NAICS 561621 (Security Systems Services (except Locksmiths)) is $25 million in average annual receipts, per 13 C.F.R. § 121.201.

Is NAICS 561621 eligible for SDVOSB, 8(a), HUBZone, or WOSB set-asides?

Set-aside programs that commonly apply: SDVOSB, 8(a), HUBZone, WOSB, VOSB. Strong SDVOSB participation, especially for facility access control and CCTV installation contracts.

Which federal agencies buy under NAICS 561621?

For FY2024 reporting, the leading federal customers under NAICS 561621 were Department of Defense, Department of Homeland Security, Department of State, General Services Administration, Department of Veterans Affairs. Live obligation data is available on USAspending.gov.

What FAR or DFARS clauses commonly apply to NAICS 561621 contracts?

Frequent clause flowdowns include DFARS 252.204-7012 (Safeguarding Covered Defense Information); FAR 52.222-41 (Service Contract Labor Standards); FAR 52.236-13 (Accident Prevention); FAR 52.219-14 (Limitations on Subcontracting); FAR 52.225-9 (Buy American — Construction Materials). Each contract instrument will incorporate clauses by reference under FAR 52.252-2; this list reflects the high-frequency set for this NAICS, not an exhaustive flowdown.

Administrative & Support Services

NAICS 561621 — Security Systems Services (except Locksmiths)

Installation, monitoring, and maintenance of electronic security systems including access control, surveillance, and alarm systems. Federal use spans military base security systems and federal facility access control.

Quick facts

SBA size standard: $25 million; Average annual receipts · 13 C.F.R. § 121.201
FY2024 federal obligations: $500M–$1B; See live USAspending.gov data →

Top federal customers

Federal agencies that obligate the most spending under NAICS 561621 (FY2024 reporting period). Order tracks federal-obligation volume on USAspending.gov.

1.Department of Defense
2.Department of Homeland Security
3.Department of State
4.General Services Administration
5.Department of Veterans Affairs

Set-aside fit

Whether NAICS 561621 commonly carries set-aside designations on federal awards. Eligibility for any specific solicitation is set by the contracting officer; this table reflects the FY2024 award pattern, not a guarantee of set-aside status.

SDVOSB (Service-Disabled Veteran-Owned Small Business)
8(a) Business Development Program
HUBZone Small Business
WOSB / EDWOSB
VOSB (Veteran-Owned Small Business)

Strong SDVOSB participation, especially for facility access control and CCTV installation contracts.

Frequent prime contractors

Companies that most frequently appear as prime awardees under NAICS 561621 for FY2024. Drawn from USAspending.gov public award records — verify currency at the live link below.

Johnson Controls
Convergint Technologies
M.C. Dean
STG Inc.
ADT Commercial
Securitas Electronic Security
Siemens
Honeywell Building Solutions
Stanley Security
Anixter (WESCO)

See live award data on USAspending.gov →

Common FAR / DFARS clauses

Frequently flowed-down clauses on contracts in this NAICS. The clause text on acquisition.gov is authoritative; this list captures the practical pattern, not an exhaustive flowdown.

DFARS 252.204-7012Safeguarding Covered Defense Information
NIST 800-171 applies on DoD security-system contracts that touch CUI.
FAR 52.222-41Service Contract Labor Standards
SCA applies to monitoring and maintenance technicians on federal sites.
FAR 52.236-13Accident Prevention
OSHA flowdowns for installation work.
FAR 52.219-14Limitations on Subcontracting
Services-based limitation on set-aside awards.
FAR 52.225-9Buy American — Construction Materials
Domestic preference for security-system equipment when delivered as construction.

Indirect rate considerations

Hybrid services / installation structure. Equipment pass-through (cameras, controllers) requires materials handling. Installation labor under SCA where applicable. Vehicle fleet recovery under USACE EP 1110-1-8 or overhead absorption.

See FieldLedger's Indirect Rate Engine for pool definition and rate tracking, or read the FieldLedger methodology for the underlying FAR Part 31 framework.

How FieldLedger fits NAICS 561621

Signed timekeeping with SCA classification. Indirect Rate Engine for materials-handling pool. Multi-CLIN invoicing for install-and-maintain task orders.

DCAA compliance →Indirect Rate Engine →DCAA readiness check →

Frequently asked

What is the SBA size standard for NAICS 561621?: The SBA size standard for NAICS 561621 (Security Systems Services (except Locksmiths)) is $25 million in average annual receipts, per 13 C.F.R. § 121.201.
Is NAICS 561621 eligible for SDVOSB, 8(a), HUBZone, or WOSB set-asides?: Set-aside programs that commonly apply: SDVOSB, 8(a), HUBZone, WOSB, VOSB. Strong SDVOSB participation, especially for facility access control and CCTV installation contracts.
Which federal agencies buy under NAICS 561621?: For FY2024 reporting, the leading federal customers under NAICS 561621 were Department of Defense, Department of Homeland Security, Department of State, General Services Administration, Department of Veterans Affairs. Live obligation data is available on USAspending.gov.
What FAR or DFARS clauses commonly apply to NAICS 561621 contracts?: Frequent clause flowdowns include DFARS 252.204-7012 (Safeguarding Covered Defense Information); FAR 52.222-41 (Service Contract Labor Standards); FAR 52.236-13 (Accident Prevention); FAR 52.219-14 (Limitations on Subcontracting); FAR 52.225-9 (Buy American — Construction Materials). Each contract instrument will incorporate clauses by reference under FAR 52.252-2; this list reflects the high-frequency set for this NAICS, not an exhaustive flowdown.
What indirect-rate structure works for a federal contractor in NAICS 561621?: Hybrid services / installation structure. Equipment pass-through (cameras, controllers) requires materials handling. Installation labor under SCA where applicable. Vehicle fleet recovery under USACE EP 1110-1-8 or overhead absorption.
How does FieldLedger help small federal contractors in NAICS 561621?: Signed timekeeping with SCA classification. Indirect Rate Engine for materials-handling pool. Multi-CLIN invoicing for install-and-maintain task orders.

Sources

U.S. Census NAICS manual — census.gov/naics
SBA size-standards table — 13 C.F.R. § 121.201 (eCFR)
Federal obligations + prime awardees — USAspending.gov NAICS 561621
FAR / DFARS clause text — acquisition.gov

Snapshot date: 2026-05-08 (FY2024 reporting period). Federal-obligation bands and prime-contractor lists reflect the data as of the snapshot — refresh against USAspending.gov for current figures.