Bullet-resistant glazing provides an improved safety barrier against ballistic attack. Bullet-resistant glazing materials include all-glass laminates, glass-clad polycarbonate laminates and other laminated or monolithic plastics.

Typical applications include banks, currency exchanges, police stations, embassies, military installations, prisons, detention centers, government offices and schools.

Ballistics Test Standards
Ballistics testing is conducted on each of the components of the bullet-resisting system (i.e., frame, glass, speakholes, passthroughs, etc.); therefore, the glazing is tested as a stand-alone component separately from the system. The test standards for glazing include:

• Underwriters Laboratories (UL) Standard 752—Standard for Bullet-Resisting Equipment; and
• National Institute of Justice (NIJ) Standard 0108.1—Ballistic-Resistant Protective Materials.

Other forced-entry test standards that include ballistics testing are:

• ASTM F 1233—Standard Test Method for Security Glazing Materials and Systems;
• H.P. White Laboratories-HPW-TP-0500.03—Transparent Materials for Use in Forced Entry or Containment Barriers;
• U.S. State Department–SD-STD-01.01– Certification Standard–Forced Entry and Ballistic Resistance of Structural Systems; and
• Walker McGough Foltz & Lylerla (WMFL)—Ballistics and Forced Entry Test Procedure.

Ballistics tests specify levels of performance based on test ammunition, nominal bullet mass, suggested barrel length, required bullet velocity and number of shots. Typical test ammunition is specified as armor- piercing, full metal jacketed, jacketed soft point, long rifle high velocity, round nose or semi-wadcutter.

The protocol also may require testing of the glazing at cold, ambient and hot temperatures. The performance of glazing products may change with test temperature.

Most test protocols included a method for evaluating the effects of spall (flying material fragments) that may come off the rear face of the glazing material when impacted by a bullet

.UL 752 has multiple levels of performance with a supplementary shotgun level. The NIJ and ASTM standards have six levels of performance.

It is important to note that there are differences between the ammunition caliber, loading and manufacturer specified in the standards, as well as differences in required shot patterns and methods for measuring spall. These factors can make a difference in whether a specific glazing construction passes or fails one of these tests.

In addition, it is important to note that a ballistics glazing product qualified at one level may not provide the performance required for a higher ballistics level.

Ballistics testing is conducted in a controlled laboratory environment to evaluate performance based on any of the tests referenced here. Test reports can be requested from the glazing manufacturer or security system manufacturer to demonstrate compliance with a particular test method.

This material was adapted from a bulletin developed by the Glass Association of North America (GANA) Protective Glazing Committee. © GANA. All rights reserved. For more information, visit www.glasswebsite.com.

Correction 
In the last edition of Metal Matters, a subhead entitled Renewable Energy should have been included after the first sentence.

Architects' Guide to Glass & Metal
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