FEMA 427 / December 2003
Risk Management Series

Primer

for Design of Commercial Buildings to 
Mitigate Terrorist Attacks 
December 2003 

FEMA 

Federal Emergency Management Agency 
www.fema.gov 

FOREWORD AND ACKNOWLEDGMENTS

This Primer for Design of Commercial Buildings to Mitigate Terrorist Attacks Ð 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 Ð 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.


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 


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

 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 

LIST OF FIGURES

2-1 Schematic of vehicle weapon threat parameters and 
 various building components, standoff distance, and risk  .....  8-2

LIST OF TABLES

4-1 Damage and Injuries due to Explosion Effects..................... 4-8
6-1 Performance Conditions for Windows ............................ 6-30



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. 

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