Why this guide exists

In 2018 Epic’s founders walked into their children’s elementary school and found security film in the vestibule that had been installed wrong — film that would have failed under impact. Nobody at the school knew. The invoice said “security film” and the film was on the glass. That is the problem with buying this product: the mistakes are invisible until the day they matter.

You don’t need to become an expert. You need to ask seven questions and know what a bad answer sounds like.

1. “Which film, exactly?”

“Security film” is not a specification. Ask for the manufacturer and product name and the thickness in mils. For forced-entry delay on entries and vestibules, the current benchmark is a thick polyurethane film such as 3M S2400 (24 mil, 560% elongation). Micro-layered polyester films such as 3M Ultra S800 (8 mil, 42 layers) are the multi-threat standard for blast and seismic. An 8-mil single-ply polyester film is a safety-glazing film, not a forced-entry film — fine for shard retention, not for an active-threat entry.

Worrying answer: “It’s 8 mil security film.” (Which one? Single-ply or micro-layered? Rated for what?)

2. “Is it attached to the frame? With what?”

Film alone holds broken glass together. It does not hold the glass in the building. Under forced entry the filmed pane can be pushed out of the frame in one piece. For break-and-entry, blast and windstorm applications 3M specifies a structural silicone sealant attachment — and any serious specification does too. Ask what attachment product is quoted and ask to see its data sheet.

Worrying answer: “The film is strong enough on its own.” Or a quote with no attachment line item.

3. “Do you remove the gasket, or run the bead over it?”

This is the question almost nobody asks and the one that matters most. Aluminum frames hold glass with rubber (EPDM) gaskets. EPDM contains oil. Sealant bonds poorly to oiled rubber, and the gasket itself is not structural — it can simply pull out of the channel. The common shortcut runs a bead of sealant over the existing gasket: one bond surface, the weakest one.

The Epic Method removes the interior gasket, seats the glass tight on cork wedges, applies the film, and tools the structural silicone into the open channel so it bonds to the frame, the glass and the film and keys into the glazing pocket — three surfaces and a mechanical interlock. See it in 3D.

Worrying answer: “We seal over the gasket; that’s how everyone does it.”

4. “Who does the installation — your employees or subcontractors?”

Security film is unforgiving of installation shortcuts and most of them can’t be seen after the fact. Ask whether the people on your site are the vendor’s own certified employees and who trained and certifies them. Ask whether 3M (or the manufacturer) audits the installer.

Worrying answer: “We use a network of installers.”

5. “What tests does the film carry, and from which lab?”

Ask for the standards by name: UL 972 (burglary-resisting glazing), ASTM F1642 and GSA TS01 (blast), ANSI Z97.1 and EN 12600 (safety glazing). Ask whether the installed system — film plus attachment on real framing — has been independently tested, not just the film on a lab buck. Be careful with ASTM F3561: it was written for complete factory-built window systems, and both 3M and the International Window Film Association state that retrofit film is not covered by it. A vendor who claims F3561 “compliance” for film is misreading the standard. Epic tested its installed system to F3561 anyway, so you have third-party data instead of an objection — read The Retrofit Gap for the result and the caveats.

Worrying answer: “It meets all the standards.”

Want to see what the wrong answers look like installed? Buyer beware: installation errors, photographed on real campuses →

6. “What does the warranty cover, and are you authorized to offer it?”

Manufacturer warranties on security film (10 years on 3M S2400 commercial, up to 15 on Ultra Prestige) apply only when the film is installed by an authorized dealer. Ask for the dealer status in writing and ask what the installer’s own labor guarantee adds on top.

Worrying answer: A warranty that only names the installer, not the manufacturer.

7. “Will you put in writing that this is not bulletproof?”

No window film is bulletproof or bullet-resistant. A vendor who hedges on this is either uninformed or selling. Security film keeps broken glass in the frame so a forced-entry opening isn’t created on the first strikes — the delay that lockdown and response depend on. That is valuable. It is not the same thing as stopping a projectile, and your board, your insurer and your parents deserve the distinction. Read our explainer.

Worrying answer: Anything other than “Correct — and here it is in writing.”

What a good quote looks like

Film by manufacturer, product and thickness, per opening
Attachment product named, with bead size per application (3/8" forced-entry and windstorm; 1/2" blast or oversized lites)
Gasket treatment stated
Installer: employees, certification, manufacturer dealer status
Test standards listed by name; independent system test data available on request
Manufacturer warranty term plus installer guarantee
A plain statement that the system is not bulletproof

If you want to see how Epic answers all seven, request a free assessment — or download the documents below and compare any quote against them.

Free download · 5 pages