Risk Management Series

Primer

for Design of Commercial Buildings to Mitigate 

Terrorist Attacks 

December 2003 

FEMA 

FEMA 427 

FEMA 427 / December 2003

RISK MANAGEMENT SERIES

Primer for 

Design of Commercial 

Buildings to Mitigate 

Terrorist Attacks 

PROVIDING PROTECTION TO PEOPLE AND BUILDINGS

Federal Emergency Management Agency 

www.fema.gov 

FOREWORD AND ACKNOWLEDGMENTS

This Primer for Design of Commercial Buildings to Mitigate Terrorist Attacks – Protecting Office, 

Retail, Multi-Family Residential, and Light-Industrial Facilities, provides guidance to building designers, owners and state and local governments to mitigate the effects of hazards resulting from terrorist attacks on new buildings. While the guidance provided 

focuses principally on explosive attacks and design strategies to mitigate the effects of 

explosions, the document also addresses design strategies to mitigate the effects of 

chemical, biological and radiological attacks. In addition to applicability to the design 

of new commercial office, retail, multi-family residential, and light-industrial buildings, 

many of the concepts presented are also applicable to other building types and/or 

existing buildings. 

ACKNOWLEDGEMENTS 

Principal Author: 

Applied Technology Council (ATC)

Eve Hinman, Hinman Consulting Engineers

Contributors: 

Christopher Rojahn, Applied Technology Council

Robert Smilowitz, Weidlinger Associates

Kenneth Mead, Centers for Disease Control and Prevention/

National Institute for Occupational Safety and Health

Dominic Campi, Rutherford & Chekene

Randy J. Meyers, Flack + Kutz Inc.

Nancy Sauer, Rdd Consultants

Peter Mork, Applied Technology Council

Project Advisory Panel: 

Christopher Arnold, Building Systems Development, Inc.

Wade Belcher, General Services Administration

Curt Betts, U. S. Army Corps of Engineers

Jim Caulder, U. S. Air Force – Civil Engineer Support Agency

Michael Chipley, UTD, Inc.

Marcelle Habibion, Department of Veterans Affairs

Joseph Hartman, U. S. Army Corps of Engineers

David Hattis, Building Technology, Inc.

Rick Jones, Naval Facilities Engineering Service Center

Kurt Knight, Department of Veterans Affairs

Frederick Krimgold, Virginia Tech

Eric Letvin, URS Corporation

John Lynch, Naval Facilities Command (NAVFAC) Criteria Office

Wesley Lyon, UTD, Inc.

Terry Pruitt, Department of Homeland Security

Lloyd Siegel, Department of Veterans Affairs

William Whiddon, Building Technology, Inc.

FOREWORD AND ACKNOWLEDGMENTS iii 
Project Officer: 

Milagros Kennett, FEMA 

Building Sciences Technology Branch 

Mitigation Division 

This manual will be revised periodically, and comments and 

feedback to improve future editions are welcome. Please send 

comments and feedback by e-mail to 

riskmanagementseriespubs@dhs.gov 

iv FOREWORD AND ACKNOWLEDGMENTS 
TABLE OF CONTENTS

FOREWORD AND ACKNOWLEDGMENTS .................................. iii

LIST OF FIGURES........................................................................ vii

LIST OF TABLES........................................................................... ix

FIGURE CREDITS ......................................................................... xi

1 INTRODUCTION............................................................... 1-1

1.1 Purpose and Overview .............................................. 1-1

1.2 Contents and Organization of the Report ..................... 1-3

1.3 Further Reading ........................................................ 1-4

2 TERRORIST THREATS.......................................................... 2-1

2.1 Overview of Possible Threats ..................................... 2-1

2.2 Explosive Attacks ...................................................... 2-1

2.3 Further Reading ........................................................ 2-4

3 WEAPONS EFFECTS ......................................................... 3-1

3.1 Description of Explosion Forces .................................. 3-1

3.2 Further Reading ........................................................ 3-3

4 BUILDING DAMAGE ......................................................... 4-1

4.1 Predicting Damage Levels .......................................... 4-1

4.2 Damage Mechanisms ................................................ 4-1

4.3 Correlation Between Damage and Injuries ................... 4-5

4.4 Further Reading ........................................................ 4-8

5 DESIGN APPROACH ......................................................... 5-1

5.1 Goals of the Design Approach ................................... 5-1

5.2 Security Principles ..................................................... 5-2

5.3 Further Reading ........................................................ 5-5

6 DESIGN GUIDANCE ......................................................... 6-1

6.1 Site Location and Layout ............................................ 6-1

6.2 Architectural ............................................................ 6-8

6.3 Structural ............................................................... 6-13

6.4 Building Envelope ................................................... 6-26

6.5 Mechanical and Electrical Systems ........................... 6-35

6.6 Chemical, Biological, and Radiological Protection ...... 6-41

7 OCCUPANCY TYPES......................................................... 7-1

7.1 Overview ................................................................ 7-1

7.2 Multi-Family Residential Occupancy ............................ 7-1

7.3 Commercial Retail Space Occupancy ......................... 7-2

7.4 Light Industrial Buildings ............................................ 7-3

7.5 Further Reading ........................................................ 7-5

8 COST CONSIDERATIONS ................................................. 8-1

8.1 Initial Costs .............................................................. 8-1

8.2 Life-Cycle Costs ........................................................ 8-2

8.3 Setting Priorities ....................................................... 8-3

8.4 Further Reading ........................................................ 8-4

TABLE OF CONTENTS v 
vi TABLE OF CONTENTS 
LIST OF FIGURES

2-1 Schematic of vehicle weapon threat parameters and 

definitions ...................................................................... 2-2

3-1 Air-blast pressure time history ........................................... 3-2

3-2 Plots showing pressure decay with distance........................ 3-2

4-1 Schematic showing sequence of building damage due 

to a vehicle weapon........................................................ 4-3

4-2 Schematics showing sequence of building damage due 

to a package weapon ..................................................... 4-4

4-3 Exterior view of Alfred P. Murrah Federal Building collapse . 4-5

4-4 Exterior view of Khobar Towers exterior wall failure ............ 4-6

4-5 Photograph showing non-structural damage in building

impacted by blast ........................................................... 4-7

5-1 Components of security ................................................... 5-2

5-2 Schematic showing lines of defense against blast................ 5-4

6-1 Schematic of typical anti-ram bollard................................. 6-4

6-2 Schematic of typical anti-ram knee wall ............................. 6-5

6-3 Schematics showing the effect of building shape on

air-blast impacts.............................................................. 6-9

6-4 Schematics showing an example approach for improving 

the layout of adjacent unsecured and secured areas ......... 6-10

6-5 Direct design process flow chart ..................................... 6-17

6-6 Single-degree-of-feedom model for explosive loads. 

Note variation of force and displacement with time........... 6-18

6-7 Safe laminated-glass systems and failure modes ............... 6-29

6-8 Plan view of test cubicle showing glass performance 

conditions as a function of distance from test window........ 6-31

6-9 Schematic showing recommended location for elevated 

air-intakes on exterior of building.................................... 6-44

8-1 Plots showing relationship between cost of upgrading 

various building components, standoff distance, and risk ..... 8-2

LIST OF FIGURES vii 
viii LIST OF FIGURES 
LIST OF TABLES

4-1 Damage and Injuries due to Explosion Effects..................... 4-8

6-1 Performance Conditions for Windows ............................ 6-30

LIST OF TABLES ix 
x LIST OF TABLES 
FIGURE CREDITS

3-1 Based on Figure 3.2, Fundamentals of Protective Design for Conventional Weapons, Technical Manual TM5-855-1, Headquarters, Department of the Army, Washington, D.C., 3 November 1, 

1986. 

4-3 Photograph courtesy of Exponent Failure Analysis Associates 

4-4 Photograph courtesy of the U.S. Air Force 

4-5 Photograph courtesy of U.S. Department of State 

6-1 Based on Figure 3-6, Security Engineering - Concept Design, 

Army TM5-853-2, Air Force AFMAN 32-1071, Vol. 2, Department of the Army, and the Air Force, May 1994. 

6-2 Based on Figure 14.9.6.1.3, Architectural & Engineering Design 

Guidelines for U.S. Diplomatic Mission Buildings, Office of Building Operations, U.S. Department of State, Washington D.C., 

June 1997. 

6-7 From Figure 4-1, ISC Security Design Criteria for New Federal 

Office Buildings and Major Modernization Projects, The Interagency Security Committee, Washington, D.C., May 28, 2001. 

6-9 Guidance for Protecting Building Environments from Airborne 

Chemical, Biological, or Radiological Attacks, Department of 

Health and Human Services, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, 

May, 2002. 

8-1 Courtesy of Joseph Smith of Applied Research Associates, Inc. 

FIGURE CREDITS xi 
xii FIGURE CREDITS