Security Window Film - Facts and FAQs

Updated: Jul 10



"Baby, please don't let me be misunderstood"

Security Window Film is one of our most exciting and also misunderstood products. That a 3M-manufactured polyester film can help hold broken glazing together, delay or prevent potential break-ins, smash & grabs, or damage from explosions or weather is amazing. Indeed, with recent events, interest in Security Window Film has grown, and we're happy to share this post and clarify the product's benefits, and also limitations.


Background & Design

Security Window Film also known as Fragment Retention Film, was first designed in the 1970s to help protect embassies from bomb blasts and acts of terrorism. Sun Control Window FIlm had already been designed, in response to temperature imbalances and rising energy prices. Security Window Film innovated on that base, thin, polyester film, with 4, 6 and 8-mil (each mil is 1/1000 of an inch) products. Thick films are applied (most often) to the inside of existing glazing, to form a protective shield, hoping to help hold broken glazing together in the event of force or an explosion. The easiest way to describe the initial use case is with the following video:



As you can see, the film bonds with glazing to help hold broken glass together and minimize the hazards of flying glass. Further reinforcing the product is a silicone-based sealant (Dow 995, 3M Impact Protection Adhesive) which helps to hold the window, film and frame together. These sealants are known as "attachment" or "anchoring" systems, and they are a critical part of helping to maintain the integrity of the building envelope.


Security Window Films help to fortify existing glazing, and for the longest time had been niche products used in response to acts of terrorism (Oklahoma City, 9/11) or extreme weather. In recent years, with mass shootings, acts of violence, and a greater emphasis on preventative security, interest in these products has grown, as has product development and innovation.


Today's Product Suite

Today, we see security films requested by architects, commercial clients, schools and houses of worship - all seeking to help reinforce glazing from bad people, weather and things. While protection from explosions and bad weather remain considerations, the vast majority of interest is in helping to buy time in the event of break-ins or acts of violence. Again the easiest way to describe the product is with a video:



The window film helps hold broken glazing together, and the attachment systems help to hold the glass, film and frame together. This particular product, a 6-mil cross-woven 3M security window film, was recently discontinued, but you get the idea. One could roughly segment the security window film landscape as follows:

  • Traditional 8-mil clear security window film

  • Cross-woven 8-mil security window film (incrementally tear-resistant)

  • Combination tinted and mirrored 8-12 mil security window films (help reduce heat, glare, provide daytime privacy, in addition to security)

  • 14-15 mil security window films

  • 21-23 mil security window films (extremely thick)

  • Always installed with an attachment system when reinforcing from break & entry


Why Buy?

So why do people buy our products? They have glass doors, storefronts, window walls which are either annealed or tempered, and extremely vulnerable to forced entry or break-ins. Professionallly-installed security window films buy time - which is valuable during an emergency - seconds and minutes matter because:

  • Intruders want quick access and exit; banging on glass for 45 seconds through 2 minutes is extremely risky and dangerous

  • Occupants can call first responders, hide, and formulate a plan

  • In the event of a seismic blast (windstorm, explosion, etc.), the pressure builds and dissipates, and all of the damage occurs once the building envelope has breached

The easiest way to think about security window film, is an inexpensive alternative to laminated glass. Professionally installed, the film looks like normal glass, performs well, and is warrantied by manufacturers for 10-15 years.


Product Specs:

Layr offers a wide selection of Security Window Film products, each coming in at different price points associated with different benefits. We wanted to provide you with some information about some specific product models that we install the most and that our customers love.

  • 3M Safety S70

  • A more affordable option than some of our more highly priced films

  • Film is single ply, .18 mm thick and has a tensile strength of 25,000 psi

  • Significantly reduces harmful UV rays


  • 3M Ultra S800

  • Film is micro-layered, tear-resistant, .20 mm thick, and has a tensile strength of 27,000 psi

  • Significantly reduces harmful UV rays

  • Micro-layered construction greatly enhances the film and makes it much more difficult to tear


  • 3M Ultra Night Vision 25

  • Combines the safety and security benefits of 3M Safety & Security Window Film with the sun control benefits of 3M Sun Control Night Vision Series

  • Micro-layered construction greatly enhances the film and makes it much more difficult to tear

  • Rejects 60% of total solar energy, rejects 99.9% of UV light, reduces Solar Heat by 51%, reduces glare by 73%, has a tensile strength of 27,000 psi and is 0.22 mm thick


  • 3M Ultra Prestige 70

  • Combines the benefits of 3M Ultra Series with the benefits of 3M Prestige Series Window Film

  • High visual light transmission providing excellent aesthetics

  • Rejects 50% of total solar energy, rejects 99.9% of UV light, reduces Solar Heat by 38%, reduces glare by 23%, has a tensile strength of 27,000 psi, and is 0.22 mm thick






Facts & FAQs:

  • How much time will I buy - the answer to this commonly asked question is both nuanced and impossible to answer, "it depends". It depends on the baseline type of glazing, the type of film installed, the framing and attachment system, the quality of the installation, the determination of an intruder and their strength / weapon. Professionally installed film will help hold for at least 45 seconds, and independent testing suggests up to two minutes. Thicker films will outperform thinner films against forced entry

  • Burglary-Resistant - thicker films (14-mils and up) rate as UL 972 Burglary-Resistant Glazing Material

  • Bullet-Resistant - no films are bullet-resistant, or have ballistic qualities. This is one of the bigger misconceptions. Bullets will go through, but the overall structure will hold up and buy tim

  • 3M Security Window Film also carries many of the benefits of Solar Window Film including:

  • Blocks Dangerous UV rays, which can cause cancer and fade interiors

  • Reduces uncomfortable hotspots inside the building

  • Tinted versions reduce the transfer of solar energy while improving privacy

  • Lowers energy use and the added cost of air conditioning

  • Blast-Resistant - most 8-mil films with proper anchoring systems rate highly on the GSA's bomb blast test (TS-2001). A highly rated film would be considered 2b (limited hazard) or below

  • Do I really need the caulking - short answer, yes. While the film will hold broken glass together, larger sheets of (especially tempered) glass will simply fall through as one flush sheet. Proper installation and adherence to a clean, strong substrate (metal) is critical to the film's performance

  • Haze / Champagne - thicker films (14-mils and up) are often made by bonding several layers of 7 or 8-mil film together. These films require more pressure to install, and also maintain more water after the installation process (films are permeable). Thicker films, similar to thicker fire-rated / safety glazing, do have a natural haze, even with nearly perfect installation. This is simply a trade-off between aesthetics and performance

  • Cost - our pricing is based on three factors; (i) type of film, (ii) size of installation and (iii) complexity of installation. Pricing is on everyone's mind, so let's dive in a little bit

  • 1) Type of Film - thicker, branded films are more expensive than thinner films from smaller brands. For instance, 3M's cross-woven, micro-layered S800 8-mil film is more expensive than a baseline multi-ply 8-mil film. 14-mil films are more expensive than 8-mil films

  • 2) Size of Installation - we price a 200 square foot storefront project differently than a 5,000 square foot school installation. We are able to stage out installation, project management, bulk-by our materials, and so on

  • 3) Complexity of Installation - certain jobs move quickly, and others require a lot more planning, logistics and labor. Smaller, irregularly-sized panes require much more cutting and produce more waste. Smaller windows tend to have a higher ratio of linear feet to square feet, and so our caulking / labor increases materially. Other related factors; scaffolding, lifts, film removal, after-hours installation - these all play into our pricing

  • To provide a simple answer, our films install on glass for $12-20 per square foot, furnished and installed and warrantied by 3M. These prices are compelling relative to the benefits, and also relative to alternative OEM glass removal and replacement

We hope this short post helped to clarify facts and FAQs regarding security window film. Feel free to drop us a line if we can help with your project!

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Tel: 888-888-8000          Email: info@layr.com
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