June 20, 2023
Bulletproof Windows In Schools: Pros, Cons, Costs & Considerations
Bulletproof Windows Schools Blog Featured Image

Sandy Hook. Parkland. Uvalde. Covenant School. Beyond being the sites of some of the worst school shootings in recent US history, each of these shootings share a commonality. In each of these shootings, an assailant shot through glass doors and windows at victims inside the schools. 

To mitigate these attacks that start outside buildings, school districts are fortifying classrooms and entryways by adding bulletproof windows and ballistic-rated glass doors to protect students and staff.

How effective is bulletproof glass for schools, and does it make sense to implement given your school’s security budget? Read on to learn more about the key features and cost of bulletproof windows, and alternative school security solutions you may want to consider.

What Are Bulletproof Windows?

Bulletproof windows, also known as ballistic windows, are specialized security windows designed to provide protection against ballistic threats like bullets, shrapnel, or other projectiles. Bulletproof windows are commonly used in high-security environments, including military installations, government buildings, banks, armored vehicles, and VIP residences. 

The construction of ballistic windows involves the use of multiple layers of specialized materials, such as laminated glass, polycarbonate, and other transparent synthetic materials. These layers are combined to create a composite structure that can withstand the impact of high-velocity projectiles.

The primary goal of ballistic windows is to provide transparent protection. This is a really important factor because a cheaper alternative to prevent someone from shooting into a school would be to pour concrete to fill every window. But concrete isn’t a viable solution because a windowless school would resemble a prison, and studies have shown that being able to see outside increases learning, productivity, and creativity.

Are Bulletproof Windows Breakable?

It is important to note that while ballistic windows offer significant protection against ballistic threats, they are not invulnerable. Extremely high-powered weapons or specialized ammunition can breach even the strongest ballistic windows. 

Luckily, the rounds most commonly used during school shootings can be stopped by most ballistic glass. Additionally, even if bullets penetrate the fortified glass layers, a shooter will still not be able to crawl through the window (like what happened in the Nashville school shooting) or reach through to open the door from the inside (like in the Central Visual Performing Arts School attack).  

Should All School Windows Be Upgraded With Bulletproof Glass?

Back in the 1990s after a commercial airline crash, comedian George Carlin wryly questioned, “If the black box flight recorder is never damaged during a plane crash, why isn’t the whole airplane made out of that stuff?” Of course, what seems like a clever idea isn’t practical because an indestructible plane would be too heavy to fly. 

Applying the same principle to school security, ballistic-rated glass is about 10 times the weight of a standard window. Most structures are not designed to hold significantly more weight than their original architectural plans. 

Retrofitting every school in the country with ballistic windows would exceed $2.6 trillion dollars* —roughly 3 times the entire DOD annual budget—not including the cost of retrofitting structures for the extra weight. 

* Based on estimated window square footage, $500 per sq/ft ballistic glass, and labor assuming 80% of 130,000 K-12 schools average 21 classrooms and 20% of schools average 100 classrooms.

How Much Do Bulletproof Windows and Doors Cost?

Glass that can stop multiple rounds from a high-power rifle costs roughly $500/sq ft. The glass alone for a 100-classroom school building with entry and hallway windows can easily exceed $20 million—just for the glass. 

Structural renovation to hold the weight of the ballistic glass can double this cost in a heartbeat. Installing ballistic glass is not a casual undertaking. Glass that can stop multiple .223 rounds weighs 8 pounds per sq./ft. which is about 10 times the weight of standard windows. 

They aren’t a one-time purchase either. Ballistic glass requires regular inspection, maintenance, and adherence to proper installation guidelines to ensure continued effectiveness. Due to the inherent UV exposure that ballistic glass gets, they need to be replaced about every 20 years because the sun breaks down the protective layers.

What Does the Process of Installing Ballistic Glass Look Like?

When most school shooters are current or former students who have awareness of the active shooter plan and fortification systems, a school system can’t get away with selectively upgrading the windows, because an insider will know to target the weakest points. 

If a school only fortifies windows and doors on the first floor, a planned attack might start by climbing onto the roof. Time and time again, determined school shooters have studied prior attacks and figured out ways to bypass security at schools.

For these building fortifications to be successful at preventing school shootings, there needs to be an in-depth analysis of every possible attack scenario combined with real-time situational awareness to ensure that fortified areas are locked and secured before an attacker enters the school.

What Are the Pros and Cons of Bulletproof Glass for Schools?

Here’s a breakdown of the top pros and cons of bulletproof glass for schools:

Pros of Bulletproof Security Windows

  • Increased Safety: Although not impenetrable, ballistic glass windows can provide added protection against gunfire. This extra layer of protection can be a matter of life and death.
  • Can Improve Response: If a school shooting happens, bulletproof glass can give students and teachers extra minutes or seconds to get away from the threat.
  • Peace of Mind: Simply knowing that classrooms are equipped with an extra layer of protection can bring peace of mind to parents, teachers, and students.

Cons of Bulletproof Security Windows

  • Expensive to Implement: Retrofitting existing classroom, hallway, and common area windows can be a huge financial burden for schools—particularly those with tight security budgets.
  • Safety Concerns: Should a door lock jam or malfunction in the event of a fire or other emergency, bulletproof glass can prevent students and staff from evacuating quickly.
  • Not 100% Bulletproof: Despite the name, bulletproof glass is not 100% foolproof. It can still be penetrated depending on weapon type and force applied. Additionally, it only provides protection if you are locked in a confined space equipped with bulletproof glass—not when people are walking through hallways or outside of classroom walls.


Solutions to a Critical Vulnerability In Ballistic Glass Security Windows

Ballistic glass can help protect students and faculty when they are inside classroom walls—but what about all the time spent outside classroom walls?  

Students need to get into the school and leave the building during the day for gym class, recess, lunch, and field trips, which means that ballistic doors will be open. If a shooter can get in while students are coming or going, or target students outside, the bulletproof glass is largely ineffective. 

Upgrading existing security camera systems with a visual gun detection platform helps ensure that an attacker won’t easily bypass your protected layers and maximizes the effectiveness of bulletproof glass. 

For example, let’s say someone walks into a school with a gun through an unopened or unlocked door. Or, they bring a gun to the school’s recreational fields or parking lot. These are all common areas equipped with security cameras. If those cameras could be used proactively to notify you of a gun, the factor that can save lives is the initial detection of the weapon and subsequent rapid response.

Why Situational Awareness Is Critical

When a shooting starts, students and staff have two options: run or lock down. If a school has ballistic doors and windows, and the shooter is detected by ZeroEyes before they get inside the building, locking these doors makes the inside of school a safe place for students to stay until police arrive.

If there’s a surprise attack inside the school, knowing the location of the shooter within seconds tells students and staff if they should run or shelter. If the shooter is nearby, it’s usually best to run away. On a large campus, if the shooter is on the opposite side of the building or in another building, it’s probably best to shelter inside behind a bulletproof door or window. 

With real-time awareness about where the shooter is, students and staff can maximize the protective benefit of ballistic doors and windows. Without a system like ZeroEyes, it’s hard to decide when it’s best to run as far away from the school as possible versus lockdown inside a classroom with ballistic doors and windows.

Proactive Gun Detection & Situational Awareness Improves School Safety

To maximize the effectiveness of the protected areas of the building, ZeroEyes’ proactive visual gun detection and situational awareness platform is layered on schools’ existing digital security cameras, where it identifies illegally-brandished guns. 

When the system detects a weapon, images are quickly screened by a specialized group of U.S. military and law enforcement veterans at one of the ZeroEyes Operation Centers (ZOC), that are staffed 24/7/365. 

Once these experts verify the threat, they then dispatch police, send text alerts to school staff, and continuously send critical information about the visual description of the attacker, gun type, and last known location. All of this happens in as fast as 3 to 5 seconds from detection, giving school staff the critical time necessary to get students to a safe area and lock ballistic doors.

Interested in implementing ZeroEyes at your school? Request a free, live demo here.


Dustin Brooks
Dustin Brooks is the Chief Customer Officer & Co-Founder of ZeroEyes. Before founding ZeroEyes in 2018, Dustin worked at Global Asset Technologies as a Military Instructor developing Navy SEAL candidates. Mr. Brooks served in the US Navy as a Navy SEAL for 6 years. Mr. Brooks earned his MBA from the Owen Graduate School of Management at Vanderbilt University, and a Bachelor of Science in Finance from Pennsylvania State University.

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