Film For Thought May/June 2020August 11th, 2021 by Nathan Hobbs
Safety Films: Uses and Testing
By Steve DeBusk
In today’s world there are many threats to our health and safety, some obvious, some not as clear. One specific to the window film industry is the hidden threat related to the glass in windows. These dangers involve potentially sharp, broken glass that can cause cutting or piercing wounds, serious injuries or death. Glass can be broken and pose a threat for many reasons: someone accidentally falling into a window or door that does not contain safety glazing; a blast event; objects hitting windows during windstorms; or even tempered glass in a highrise building containing impurities that can lead to the glass “spontaneously” breaking.
Laminated Glass Solutions
A typical solution to help address the above listed issues during new construction is to use laminated glass.
For buildings where laminated glass is not in place and the cost to replace existing glass would be high, one cost-effective and time-tested option is to apply safety and security films to windows to help provide protection. Safety and security window films range from 4- to 15+ mil in thickness and are thicker than typical home, building or auto solar-control films (1-2 mil). These films utilize a strong pressure-sensitive adhesive to adhere the film to glass and help hold broken glass together in the event of breakage. Both clear and solar-control versions of safety films are available.
Items to Consider
To help you promote safety and security films to your customers properly and to help you compare films among manufacturers, here are some important items to consider.
• Comparison of “end-use” tests are preferred over comparing film physical properties. Physical properties include film tensile, peel, puncture or tear strength and involve laboratory testing of
a small sample of film. End-use or performance tests are simulations of actual events using rigorous scientific test methods (discussed in more detail below) for blast, forced entry, etc., and
are conducted on actual windows with safety film applied. End-use tests measure the filmed windows’ reaction to being exposed to these events and are conducted by independent, accredited laboratories. The International Window Film Association suggests: “Physical properties may not be indicative of films performance under various natural or human caused events. Performance tests may be necessary or desirable to prevent false or misleading performance claims.²”
A few details about the most common end-use tests for each potential hazard:
• Safety Glazing – Test standards: ANSI Z97.1, CPSC 16CFR 1201, EN12600. Typically, ANSI Z97.1 Class A, CPSC Cat II, or EN12600 Class 1B1 are required by building inspectors. When impacted from either the film side or glass side, samples will not have an opening larger than 3 inches. Impacts are with a 100 lb weight dropped from 18 or 48 inches.
• Blast – Test standards: GSA TS01, ASTM F1642, ASTM F2912, ISO 16933 and ISO 16934. Some of these are shocktube tests where the test is conducted indoors in a large steel chamber using
pressurized air. Other tests are conducted outdoors with explosives. The General Services Administration (GSA) standard is the most-often quoted standard in bids and requires a minimum 4-psi blast pressure, however, most manufacturers have tested above this pressure. Due to the differing ways each standard scores results, it is not possible to give a complete overview here, but generally the overall requirement is that glass does not enter into the occupied area by more than 3 feet. A preferred result is GSA Level 2 or equivalent, where all glass is maintained in the frame. Blast pressure and impulse, and glass type are all critical to correctly compare reports from different manufacturers. Also important is whether an attachment system, such as structural silicone,
or if a “daylight” application with no attachment was tested. Attachment systems are typically needed for higher blast pressures and tempered glass.
• Windborne Debris – Objects blown around during a windstorm can break windows and allow wind and rain to enter, causing significant damage. ASTM E1886 and E1996 are the most-often
used test methods, where multiple filmed windows must first pass an impact test from a 2” x 4” wooden “missile” shot from an air cannon, then pass 9,000 cycles of air pressure (simulating the
windstorm) without an opening that would allow significant air or water to enter. Compare size and weight of the missile and the air pressure used during cycling. Most common is a Level C missile (4 ft x 2” x 4” wood) and air pressure reaching a maximum of 50-75 pounds per square foot (approximately a 140-mph wind).
• Forced Entry – EN-356 is the most-used test within the window film industry to demonstrate films capable of helping provide break-in protection. Evaluators of manufacturer test reports should carefully note which side of the glass is impacted during this test (film side or glass side) and compare to how the safety film will be installed in a building. Be sure to check test reports for glass thickness and type–tempered glass is much stronger than annealed and dual-pane glass provides better protection than single-pane. UL-972 is not a valid test for field-applied films as UL restricts testing to only original windows and doors from manufacturers.
• Spontaneous Glass Breakage – As noted earlier, impurities in tempered glass can lead to this type of glass suddenly breaking, leaving a dangerous opening. Films with an attachment system
have been applied to tempered glass windows, the glass broken and then subjected to the 9,000 cycles of the windstorm test. These tests should enable building management to have confidence that these films should safely keep glass in place until it can be replaced.
Modern safety and security films can help provide a wide range of significant protection for your customers. This part of the industry can be intimidating for some, with many technical details and necessary test reports. Hopefully the above information can help take away some of the hesitation to promote these powerful films and help you make informed recommendations to your customers.
2. IWFA Exhibit A, Policies and Procedures, Endorsed Testing Standards and Methods, December 2017.
Steve DeBusk is the technical enablement manager for Eastman Performance Films, LLC. DeBusk has over 25 years of experience in the window film industry including developing and testing safety and security films to a variety of test methods and assisting sales reps and dealers with numerous projects involving architectural and safety and security films.
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