Forcible Entry Demonstrations
Page 2
Air-blast Resistant Window Systems
Executive Summary
The General Services Administration (GSA) and other government agencies are
retrofitting the windows of existing buildings to mitigate the effects of flying glass in the
event of an explosive terrorist attack. Little is known about the consequences such
retrofits can have for emergency responders who may need to gain emergency access
and/or egress through windows. The GSA and the Department of Homeland Security
(DHS) contracted with Hinman Consulting Engineers, Inc., to perform forcible entry
testing of certain selected air-blast-resistant windows and window retrofit systems
commonly found in GSA buildings nationwide. In collaboration with the Protective
Glazing Council, and the San Jose Fire Department, Hinman Consulting Engineers, Inc.,
conducted these tests on May 28, 2003. This report lists the window configurations
tested, describes the procedures employed, and summarizes the findings of the tests.
Over the past twenty years, the federal government has been retrofitting the windows of
existing buildings to mitigate the effects of explosive attacks. Recently, the number of
available air-blast-mitigating retrofits has expanded, as has the number of buildings
receiving retrofits. This increases the potential for firefighters to find these enhanced
window systems on buildings during fire and other emergencies.
The windows and window treatments included in these demonstrations were selected to
represent an array of configurations representative of the most prevalent air-blast
resistance window retrofits and upgrades. This is not considered to be a complete catalog
of all air-blast-resistant retrofits or window types. The samples were chosen to answer the
basic question of whether forcible entry of typical air-blast-resistant window systems is
possible using standard firefighting tools. Table ES-1 lists window configurations
addressed in these demonstrations.
Table ES-1. Window Configurations
Air-blast-Resistant System
Glass Type
Attack Side
Floor Level
AG
Exterior
1
AG
Interior
1
Daylight film
AG
Exterior
2
TTG
Exterior
1
TTG
Interior
1
TTG
Exterior
2
Four-sided attached film
AG
Exterior
1
AG
Interior
1
AG
Exterior
1
Four-sided attached film with center seam
AG
Interior
1
TTG
Exterior
1
Two-sided attached film
TTG
Interior
1
Two-sided attached film
TTG
Interior
1
with center seam
Single-paned laminated glass
AG
Exterior
1
with 0.030-inch interlayer
AG
Interior
1
TTG
Exterior
1
Single-paned laminated glass
TTG
Interior
1
with 0.060-inch interlayer
TTG
Exterior
2
Insulating glass units with inner pane laminated
AG
Exterior
1
Hinman Consulting Engineers, Inc
www.hce.com
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