UFC 4-010-01, DoD Minimum Antiterrorism Standards for Buildings (12 December 2018, Change 3, 24 May 2024)

Overview

The document traces back to the 1996 Downing Commission report on the Khobar Towers bombing, which found that fixed DoD facilities had no force-protection standards. The first version was published as an interim standard in December 1999. Its purpose today is to set minimum engineering measures where no threat or level of protection has been determined under UFC 4-020-01, reducing mass casualties and collateral damage in a terrorist attack. The text is updated through Change 3 (24 May 2024).

The philosophy is explicit: comprehensive protection of every inhabited building against all threats is cost prohibitive, but appropriate measures can be provided for all personnel at reasonable cost. Those measures rest on five strategies: prevent building collapse, minimise hazardous flying debris, provide effective building layout, limit airborne contamination and provide building mass notification. They are mandatory for new construction and apply to existing buildings through triggers such as major investments. They cover inhabited buildings (routinely occupied by 11 or more DoD personnel); low occupancy buildings are excepted.

Chapter 3 presents the current arrangement after several standards were retired: Standard 3 (drive-up/drop-off areas) and Standard 4 (access roads) are removed, and Standard 6 (progressive collapse) moved to UFC 4-023-03. The remaining standards cover standoff to the installation perimeter, unobstructed space, structural isolation, reinforced masonry, glazing, entrances and doors, roof access, overhead-mounted items, air intakes, mail room ventilation, emergency air distribution shutoff, under-building access and mass notification.

The limits: it covers only DoD inhabited buildings, so a typically unmanned data hall may fall outside the mandatory scope. The threat level is project specific and set through UFC 4-020-01; this document provides only the baseline. Appendix C gives representative standoff distances for conventional construction and Appendix B best practices. A data centre designer should read it as a source of concrete site criteria (intake heights, damper leakage, distances).

Key points

1. The minimum standoff from a new building to the installation perimeter is 20 ft (6 m) when at least 30 ft (9 m) of clear zone lies outside, with an aggregate of at least 50 ft (15 m) including inner and outer clear zones; with no outside clear zone it is 50 ft (15 m).
2. Unobstructed space runs from the building to the inner clear zone edge or 33 ft (10 m), whichever is less, with nothing that can conceal a 6 in (150 mm) cube; foliage of trees and shrubs must not extend lower than 3 ft (1 m) above ground.
3. Trash containers, fuel tanks and electrical or mechanical equipment may sit in the unobstructed space only if they offer no concealment or are enclosed on four sides and the top; gaps in the enclosure and to the ground must be less than 6 in (150 mm).
4. Air intakes in new construction are at least 10 ft (3 m) above ground; existing buildings may reach that height with chimney-like extensions.
5. The emergency air distribution shutoff needs at least one switch per floor with no more than 200 ft (61 m) travel to the nearest switch, and the HVAC and outside low-leakage dampers respond within 30 seconds.
6. Low-leakage dampers are limited to 3 cfm/ft2 (15 L/s/m2) at 1 in. w.g. (250 Pa) differential.
7. HVAC serving critical areas such as computer rooms is not shut down; only its dampers to the outside close, and code-required systems such as biocontainment labs keep their dampers open.
8. Overhead-mounted items of 31 lb (14 kg) or more must resist 0.5 times their weight horizontally and 1.5 times downward.
9. Glazing must be at least 1/4 in (6 mm) polycarbonate or laminated glass; monolithic glass or acrylic and film or curtain retrofits do not comply. Unreinforced exterior masonry is prohibited (vertical reinforcement at least 0.05%, horizontal at least 0.025%).
10. An inhabited building is one routinely occupied by 11 or more DoD personnel at a density above one person per 430 gross ft2 (40 m2).

Using it in design

• On the site plan check the minimum standoff between the security line, clear zone and building (20/50 ft) and the 33 ft unobstructed space; define for outdoor chillers, generators and fuel tanks a no-concealment layout or a four-sided enclosure.
• Place fresh-air intakes at least 10 ft (3 m) above ground; if a ground-level intake is unavoidable, put it inside an enclosure.
• For data hall HVAC define the emergency shutoff logic: systems serving critical areas keep running while the dampers to the outside (3 cfm/ft2 maximum leakage) close; the standard names computer rooms explicitly.
• Provide roof access from an internal stair or mechanical room rather than an external ladder, and control access to crawl spaces and utility tunnels.
• For heavy overhead equipment (cable trays, ducts, lighting) check the 0.5 horizontal and 1.5 vertical weight factors in addition to seismic design loads.
• Establish whether the project actually falls under this document (inhabited building, 11 people); even if not, run a site threat assessment on the UFC 4-020-01 principle.

Who should read it

Architects, mechanical engineers and security consultants making data centre site layout, facade and HVAC security decisions.

Document contents

1. Chapter 1 Introduction: background, purpose and scope, applicability, exceptions, occupancy calculation
2. Chapter 2 Philosophy, Design Strategies, and Assumptions
3. 3-2 Standard 1 Standoff Distance
4. 3-3 Standard 2 Unobstructed Space
5. 3-6 / 3-8 Standards 5 and 7 Parking Beneath Buildings or on Rooftops, Structural Isolation
6. 3-10 / 3-11 Standards 9 and 10 Exterior Masonry Walls, Glazing
7. 3-12 / 3-13 Standards 11 and 12 Building Entrance Layout, Exterior Doors
8. 3-14 / 3-15 Standards 13 and 14 Mail Rooms and Loading Docks, Roof Access
9. 3-16 / 3-20 Standards 15 and 19 Overhead Mounted Architectural Features, Equipment Bracing
10. 3-17 / 3-18 Standards 16 and 17 Air Intakes, Mail Room and Loading Dock Ventilation
11. 3-19 Standard 18 Emergency Air Distribution Shutoff
12. 3-21 / 3-22 Standards 20 and 21 Under Building Access, Mass Notification
13. Chapter 4 Standards for Expeditionary Structures
14. Appendix A Recommended Antiterrorism Measures for New and Existing Buildings
15. Appendix B Best Practices
16. Appendix C Representative Standoff Distances for Conventional Construction

Read the document

Publication details

Authors

U.S. Army Corps of Engineers (USACE); Naval Facilities Engineering Command (NAVFAC); Air Force Civil Engineer Center (AFCEC)

Publisher

U.S. DoD (UFC)

Year

2024

Document language

English

Source type

Government / public

Access

Open licence — downloadable

Licence

U.S. public domain — U.S. Government work; free to reuse

Licence evidence

www.copyright.gov

Citation