Through the window: Security glass magnified

Figure 3: Contrast between the International Code Council (ICC) 500 and FEMA P-361. Photo courtesy
Figure 3: Contrast between the International Code Council (ICC) 500 and FEMA P-361.
Photo courtesy

In the 5-aa tests, a 7.62-mm rifle (e.g. AK-47) is used. However, each one has different requirements for the number and placement of bullets. Ballistic resistance is not required, but is rather used as a means to test the products behavior after it has been compromised with bullet holes. After all, a standard door, frame, or window cannot stop these bullets. Each test is timed and meant to replicate an attacker with a firearm and/or tools trying to gain entry into a space. Failure in these tests is constituted as any means by which an attacker can create entry, whether a 100-mm (4-in.) hole is developed to allow someone to reach a door handle or panic device, unlock and open a window, or compromise the hardware on a door to open it.

The 5-aa1 test method sets standards for forced entry in both new construction and renovations of existing structures and systems. In this test, the glass is installed into the same or similar aluminum glazing systems specified or existing on the project, such as entry doors, storefronts, and curtain walls. Unlike HPW and ASTM standards, the 5-aa1 method provides a testing guideline to incorporate the entire system, rather than just the glass in a commercial building project. In this test, the glass is first shot five times with a 7.62-mm rifle in a concentrated area and then subjected to a barrage of attacks from bricks, a 454-g (16-oz) claw hammer to incorporate a sharp object, a baseball bat, and a 5-kg (12-lb) sledgehammer. All of these impacts are concentrated at the area where the glass was shot. The test is timed from start to finish, unless the ‘attacker’ needs a break (here the time stops). In a real-life scenario the attacker cannot afford to take a break because it provides time for first responders to arrive.

The 5-aa5 test method takes the 5-aa1 standard to another level by incorporating an entire aluminum and FRP entry system used in either the exterior or interior of a building. This test establishes standards for forced entry and the ballistic-resistant levels of protection for various threats based on the Federal Bureau of Investigation’s (FBI)’s report “A Study of Active Shooter Incidents.” Here, the test uses a full system setup where glass, door(s), framing, sidelight, and hardware are assembled as they would be in the field and are tested as a whole. Both 7.62-mm and 5.56-mm (e.g. AR-15) rifles are used. However, this time, 30 shots are fired at areas such as the glass, door-locking mechanism, door handle, hinges, doorframe, and areas around the door hardware. The ‘attacker’ is then given the same tools used in the 5-aa1 test to gain entry in any way possible.

The 5-aa10 test method was also developed as a result of the 2014 FBI active shooter report, but this sets standards for wood and hollow metal doors, frames, glass, and hardware because they are more commonly used in the interior of buildings. This test uses a greater number of 7.62-mm bullets fired at concentrated areas where entry can be made. Thirty shots are fired within a 150 x 150-mm (6 x 6-in.) area comprising the door handle and the locking mechanism and then 30 shots are fired in the same side area of the door glass closest to the handle. If applicable, 30 shots are then fired at the sidelight glass closest to the door handle. After this barrage of gunfire, the ‘attacker’ will have a minimum of three minutes using handheld tools and a simulated assault rifle to gain entry through the system.

Bomb blast

Prior to the 1995 Oklahoma City bombing of the Alfred P. Murrah Federal Building, there were no minimum physical security standards for non-military, federally owned, or leased facilities. As a result, the General Services Administration (GSA) and newly formed Interagency Security Committee (ISC) sought to develop standards for buildings subject to bomb blasts. From this, ASTM created ASTM F1642, Standard Test Method for Glazing and Glazing Systems Subject to Air-Blast Loadings. This test method provides a hazard rating of glazing systems that are subject to an air blast. Understanding these ratings provides one the ability to assess the potential risk of bodily injury and facility damage.

Air-blast testing requires the complete glazing system to be tested, not just the glass. The tests can either be as an ‘arena test’ performed outdoors in a remote area where larger curtain wall and storefront systems are tested, or a ‘shock tube’ method indoors with a testing capsule for smaller openings such as windows and doors.

Standard annealed or tempered glass will carry a performance rating of five, translating to a high hazard level as per GSA/ISC protection levels for glazing. Low- and no-hazard levels are mainly comprised of glazing that is either laminated or tempered/annealed glass with a retention film applied to the interior side. Both products have their positives and negatives, but laminated glass has the benefit of being tested to alternative security glazing testing methodologies like ballistic resistance and forced-entry resistance, in addition to its higher aesthetics.

Sometimes referred to as ‘security films,’ blast-retention films were designed to prevent glass from becoming shrapnel in a blast. The advantage of using such film products, specifically in retrofit scenarios, is the film can be applied over existing glass and then secured by using either silicone or a mechanical attachment system. It is important to note, these films were only designed for blast that is a highly pressurized pulse of air. Such products do not perform as well when impacted by blunt objects and tear easier than laminated glass when a hole is developed. Common negatives associated with film products is their exposed plastic surface is prone to scratching, tends to yellow from ultraviolet (UV) exposure, and carry a shorter lifespan than laminated glass. It is also pertinent to remember, applying film to an insulated glass unit (IGU) will likely void its warranty. It is important to consult the IGU fabricator prior to applying any film.

Leave a Comment


Your email address will not be published. Required fields are marked *