Security Window Film Selection | Total Security Solutions

While there’s no such thing as “bulletproof” window film (and you should steer clear of any vendor claiming to offer it), security window film does offer other forms of protection. That’s why we offer a wide range of film solutions. To determine which is right for you, you’ll need to assess your existing windows and doors and fully understand the threats you want to protect against.

Here’s what to look for and how to choose the solution that best fits your application.

What Is Window Security Film, and What Does it Do?

Security window film is a thick polyester plastic that can be applied to existing glass.

It holds broken glass together after impact, slows intruder entry, and prevents injury from broken glass and debris.

Security window film comes in a range of thicknesses and is lab-tested under several recognized standards to verify durability and performance under a variety of conditions. These include extreme weather, vandalism, burglary attempts, and even explosive blasts. Untreated glass can be breached within seconds.

Properly installed security film anchored by the right attachment system will delay entry by several minutes, giving law enforcement and first responders time to arrive on the scene, and allowing building occupants to seek a safe place. It’s ideal for areas where you want to delay forced entry but don’t need ballistic protection. This may include:

• High transom windows and skylights
• Side entrances
• Interior glass doors and windows within your security perimeter
• Basement windows
• Display windows

Security window films can also help improve building efficiency and comfort. Most safety and security films are available with various aesthetic options like tints and mirroring. These can reduce heat transfer by 50% or more. Even clear security films block more than 99% of UV light.

It’s worth noting that while safety and security films are a valid component of most security strategies, they should never be treated as a replacement for ballistic glass. There is no such thing as “ballistic film” or “bulletproof window film.”

No product on the market today can be applied to existing glass windows and reliably stop even small caliber bullets. We have explored the concept extensively and found that even multiple layers of the thickest available security window films failed to perform reliably. While ballistic glass has been tested to the UL 752 Standard for Bullet-Resisting Equipment, film does not meet these standards and cannot be trusted to stop bullets.

Understanding Window Security Films

Safety and security films are usually categorized by thickness, measured in “mil.” One mil equals one-thousandth of an inch (i.e., .001 inch or 0.025 millimeters). Most security window films range between 4 mil (roughly the thickness of a dollar bill) to 15 mil (around the thickness of a business card), and can be as thick as 24 mil (about as thick as a credit card).

Thickness is only part of the story. You must also pay attention to the film's tested “peel strength” and “break strength.” Both are measured in PPI (pounds per inch).

• Peel strength measures how well a film holds a broken window together, delaying entry, preventing injury, and keeping out the elements if a window is broken in a storm. If a window film has a peel strength of 5 PPI, it takes five pounds of pressure to peel one inch of the film off of the glass.
• Break strength measures how much effort it will take for someone to breach the security window film barrier. If a window film has a break strength of 200 PPI, it takes 200 pounds of pressure focused along a single inch to tear the unsupported film. If pressure is spread across a larger area, it takes more force to tear. This makes sense; you can probably imagine that a 200 lb. person putting all their weight behind the flat end of a pry bar would be able to break through a barrier more quickly than someone leaning their shoulder into the glass.

At TSS we offer three thicknesses of window film that we’ve found most useful in physical security applications:

Security Window Film Spec Comparison

What Should I Ask When Selecting a Security Window Film System?

The two most important questions to ask when considering a security window film are one, To what standards is the film tested?, and two, How is the film anchored?

We’ll discuss each of these in more detail below.

What are the testing standards for security window films?

These four standards are most commonly used to assess security films.

• ANSI Z97.1—Standard for Safety Glazing Materials Used in Buildings: ANSI Z97.1 is the baseline pass/fail test for any security film. It uses a weighted pendulum to strike the film-treated glass. The window can crack or break after being struck as long as it doesn’t create an opening large enough for someone to force their hand through.
• UL 972—Standard for Burglary Resisting Glazing Material: UL 972 is a pass/fail test for resisting smash-and-grab robberies and break-ins. During the test, a five-pound steel ball is repeatedly dropped from at least 10 feet onto a horizontally mounted sample of the film-coated glass. If the ball breaks through, the sample fails the test.
• GSA Standard Test Method for Glazing and Window Systems Subject to Dynamic Overpressure Loadings (aka “GSA Blast”): This is the U.S. General Services Administration’s standard for testing how well complete window systems (including glazing, sealants, frames, and anchors) cope with “dynamic overpressure loadings,” such as explosions. Ratings range from 1 (“Glazing does not break. No visible damage to glazing or frame”) to 5 (“Window system fails catastrophically.”) Security window films should at least rate a 3a or 3b, which means that window fragments might enter the protected space but won’t travel far or fast enough to cause injuries.
• ASTM E1886 and ASTM E1996: ASTM E1886/E1996 are a set of standards that rate building materials according to how well they resist extreme weather. Security window films will usually focus on the “large missile” portion of these standards, which requires stopping various sizes of 2x4 launched at the treated sample to simulate hurricane-driven debris. If a film-treated window can stop nine pounds of 2x4 flying at 50 feet per second, it can stop a thrown brick or cinderblock.

Why does the anchoring system matter?

Security film will hold your window glass together and protect people from flying glass. However, if the unbroken piece of window glass pops entirely out of the frame, there will still be a big hole in your wall. This is where anchoring is critical: if a security window film is applied to the glass, it should be anchored to the window frame to ensure the glazing stays in place, preventing entry or injury. Proper anchoring is always important, especially when you are looking at blast rating and severe weather.

There are many approaches to anchoring security window films. The two that we find give us the most options, in terms of both safety and aesthetics, are wet-glaze anchoring the GullWing® Anchoring System.

• Wet-glaze anchoring is similar to caulking. It uses a heavy-duty silicone structural adhesive. Once cured, that silicone adhesive enhances film performance by forming a hard, extremely durable bond with the frame.
• GullWing® anchoring relies on a proprietary flexible membrane affixed to the window film, window, and frame.

These are roughly comparable solutions in terms of performance. In most cases, choosing one over the other comes down to what will be easiest to install on the existing window frames.

Match the Window Film to the Threat: Break-ins, Bombs, Natural Disasters

If you don’t fully understand your risks, you won’t make good decisions about effective protection. As with everything else in physical security, there is no one-size-fits-all solution when picking safety and security films. Define your goals, and then choose a film that ticks all your boxes.

Forced Entry Protection

• Goal: Preventing break-ins, targeted attacks, vandalism, economically motivated crime, etc.
• What to look for: ANSI Z97.1 (baseline impact rating) is a good place to start; UL-972 Anti-Intrusion certification is the gold standard for preventing forced entry. Confirm that any quote includes wet-glazing or GullWing anchoring.
• Applications: Ground-level retail glazing, non-public-facing office windows, secondary or service entrances, interior windows, and storefronts.

Blast Protection

• Goal: Protecting against explosions. Although this test isn’t specific to natural disasters or riots, blast protection is generally also understood to protect against both extreme weather and civil unrest.
• What to look for: GSA blast rating no higher than 4. Anchoring is extremely important here, because of how explosive pressure builds across the surface of a window. You will need the anchoring system that makes the most of existing framing and structures.
• Applications: Blast-rated window films are most often used in government offices and critical infrastructure, but are also increasingly common for faith-based organizations.

Severe Weather and Impact Protection

• Goal: Protection from wind-driven debris, hurricane/tornado/storm impact, and related natural disasters.
• What to look for: ASTM E1886/E1996 “large missile impact” rating of Category B, C, D, or E. Sturdy anchoring is an absolute must.

• Applications: Regions prone to extreme weather, especially tornadoes and hurricanes. Note that these are the most rigorous tests, and most challenging to pass. Not all security window films offer extreme weather and natural disaster protection, but properly anchored window films that pass ASTM E1886/E1996 will increase your protection against human threats while improving natural disaster preparedness.

TSS Is Your Partner in Safety and Security Planning

No window film can stop bullets, but used properly, security film goes a long way in protecting people and property from a range of hazards, natural disasters, attacks, and other threats.

Understanding your risk level is essential to making sound physical security decisions. That’s why, at TSS, we believe that a solid risk assessment is the best place to start.

We’re pleased to make free materials available to support good, comprehensive security planning. If you have any questions, or are ready to begin moving forward with a project, we’re here to help.

Schedule a consultation to get started.