Bulletproof glass, blast-proof glass, forced-entry glass.
These are all mainstays in the security industry.
While each has very different use cases and performance standards, some products may be able to serve more than one purpose. When that’s possible depends on specific testing and product factors that we’ll outline in this article.
Security glass products are referred to in the industry as 'glazing'.
There are many different types of specialized glazing available; they have different compositions, but generally involve laminating different materials to create a product able to resist different types of force.
Some common materials include glass, acrylic, and laminating adhesives.
Blast resistant windows can be manufactured from materials such as polycarbonate, laminated glass, steel, aluminum, and composites to withstand explosive threats.
Blast-resistant windows are commonly used in high-risk buildings and industries, such as government facilities, embassies, and critical infrastructure, due to their ability to provide enhanced protection against explosions and forced entry. In the composition of blast-resistant glass, a laminate coating holds shattered glass fragments together, reducing the risk of dangerous flying shards during an explosion.
These products are similar, but this does not mean they will all withstand any type of attack.
Different glazing products are tested to specific standards, and rated to specify the minimum protection expectations, including the type of resistance to speed and penetration.
These standards are critical to any security product.
Specialized manufacturers offer window systems tested to various safety standards for blast resistance, and many manufacturers offer fully customizable options, including custom dimensions to meet specific project requirements.
The Department of Defense, General Services Administration, and American Society of Civil Engineers all have established blast-resistant standards.
Blast-resistant windows' performance is tested according to standard methods such as ASTM F1642-04 and GSA/ISC Performance Conditions, which involve rigorous test procedures evaluating how these windows respond to blast conditions and ensure compliance with both industry and safety standards.
Other consumer goods might be able to make claims about performance without putting lives at risk. But when you’re counting on glazing to protect people from an explosion or active shooter, having verified third-party products is critical to ensure product performance when it matters most.
It’s important to note that no blast-proof, bulletproof, or forced entry-resistant product will stop an attack indefinitely.
Repeated shots, blasts, and blows will eventually break through. What makes these products helpful is that they buy time. If an aggressor can’t immediately get in, there’s time to pull the silent alarm, call the authorities, or get to a safe location.
Below, we discuss what makes each product unique.
Bulletproof glass is designed to slow, deform, and stop a bullet. The specific construction of each bullet-resisting glazing panel depends upon the anticipated threat level. As the number of shots, bullet speed, and the bullet’s destructive profile increase, protective level of the glazing needs to increase.
Many bulletproof windows also offer impact resistance and impact protection against forces like hammers or hail because the ballistic glazing laminated-panel makeup is similar to forced impact panels.
However, bulletproof glass is not always tested or rated to stop blunt force attacks or severe weather. The only way to truly guarantee bulletproof (and blunt-force) protection is to buy a rated product that is independently tested to a recognized standard.
UL 752, the Standard for Bullet-Resisting Equipment, is most commonly used for commercial bullet-resisting equipment, including bulletproof glass.
The specific UL rating indicates the number of bullets, bullet construction, velocity, and other factors it can be expected to stop when fired from a specific distance. For instance:
Blast-resistance tends to have greater variation in use cases compared to other types of security glazing.
First, there are different types of blasts.
Different explosions created by different devices in different proximities have remarkably different effects.
Second, blast-resistant standards vary, covering both the effects of intentional detonations and unintentional detonations of fuels, gasses, oxidizers, reducing agents, and even finely powdered materials like flour and sugar in commercial and industrial settings.
Blast-proof glass must also be able to protect people from the pressure wave that follows a bomb blast.
The primary cause of blast-related injuries is glass fragmentation, which occurs when conventional glass shatters in the explosion, which can cause extensive injuries, especially as the pressure wave shatters glass beyond the immediate blast radius.
Blast-resistant windows are often made with laminated glass or polycarbonate to enhance safety and reduce the risk of injury.
Glazed blast-proof materials must eliminate glass shards (or 'spalling') and keep the system well-anchored to the wall. Even if the glass stays intact, if the whole window blows out of the frame, it can be incredibly dangerous.
Blast-resistant windows are rated based on their ability to withstand specific levels of explosive pressure.
The most common standard is ASTM F1642, the Standard Test Method for Glazing and Glazing Systems Subject to Airblast Loadings.
This test measures how well glazing or a glazing system remains intact under pressure caused by blasts in a controlled environment.
It focuses on:
The most appropriate rating for your project depends on many different factors, including the required level of safety, the hazard level, and the type of personnel and interior space being protected. High-hazard level and low protection ratings indicate catastrophic window failure, where fragments may enter the space and cause harm.
Please note that while we do not offer blast-rated products, we can advise you on the appropriate physical security standards for your project.
Different materials can more effectively withstand blasts.
Polycarbonate is 250 times stronger than glass and can withstand a pressure wave without shattering. Laminated glass contains a layer of plastic between glass panes, which prevents it from shattering into dangerous shards.
Thermally tempered glass is four times stronger than annealed glass and crumples rather than producing deadly shards when broken.
For optimal effectiveness, blast-resistant windows must be paired with reinforced framing systems securely anchored to the building.
Advanced blast-resistant window systems may include pressure-release mechanisms to prevent total structural failure during a blast.
Reinforced frames are usually constructed from thick-gauge aluminum or steel to resist deformation under extreme loads. Heavy-duty frames made of steel or aluminum are securely anchored to the building's structure, preventing the entire unit from blowing inward during an explosion.
Like blast-resistant glass, there are several common standards for forced entry-rated glass.
The UL 972 Standard for Burglary Resisting Glazing Material addresses one specific type of threat, but others are used more frequently
ASTM F1233, the Standard Test Method for Security Glazing Materials and Systems evaluates how glazing performs under multi-stage attacks, including blunt-force strikes and sharp objects.
It assigns different performance classes based on how long the material resists breakage.
Products like our SchoolDefender® Glass, a laminated glass-clad polycarbonate pane tested to this standard, are designed to delay forced entry and allow critical time for first responders to arrive. For areas that don't need blast protection or ballistic protection, they are a cost-effective option as they fit most existing frames and are a stronger alternative to security window film.
Security window films can fit into your overall physical security profile as a way to delay forced entry and keep glass intact after it has been broken. They are never a substitute for ballistic glass or blast-resistant glass.
Watch this short video to learn more about the differences between bulletproof glass and security window film.
Another common standard for forced-entry resistant glass is ASTM F3561, Protecting Entry Points After the First Shot.
ASTM developed this standard in response to emerging patterns in active shooter events in which an attacker fires at a window or door panel and then forces their way through the opening. It measures how well the system remains intact after a series of pendulum strikes.
For windows and doors that need both ballistic resistance and forced-entry resistance, our Active Shooter Window System offers dual protection.
It remains intact after rifle fire and repeated strikes, buying critical time for occupants to shelter in place or evacuate while first responders arrive. Each system is custom fabricated with a wide range of frame finishes and glazing options. As threats continue to evolve, dual ballistic and forced-entry protection is becoming the new standard for schools, corporate campuses, healthcare facilities, and government buildings.
To determine what kind of protection you need for your facility, you should start by performing a physical security risk assessment.
Predicting the types of threats you expect and deciding what measures are best to mitigate those threats will help you plan out your steps for installation or retrofit.
Since bulletproof, blast-proof, and forced-entry resistance can involve different types of materials and costs, this distinction can be critically important to the planning process.
Maybe. Unless glazing has been independently tested to an accepted industry standard, you have no guarantee it can stop a bullet.
Determining the right glazing to use involves many factors, some of which included whether people, critical infrastructure, or other property are located behind the area to be protected. It is always best to involve a knowledgeable physical security consultant to determine the right glazing type for your specific situation.
There is more force behind a bullet shot from a rifle than a hammer swung by a person. So while forced entry glass might be very strong, it simply is not designed to resist bullets. The same may be true for explosion-proof glass. So, no matter what your concern is, make sure the product you choose has been tested to the appropriate industry standard.
When lives are at stake, it’s critically important that you have a clear understanding of the limitations of any product rated for bullet-resistance, blast-resistance, and forced-entry resistance.
In these situations, we always recommend working with a security professional to fully understand whether the products meet your requirements and expectations.
While we don't offer blast-resistant windows, we have a wide range of ballistic glass as well as glazing tested to common standards for forced entry.
We have extensive experience providing other solutions to support existing blast resistant buildings, including windows, doors, frames and accessories.
Every facility is different.
The best way to get specific recommendations for your use case is to talk to an experienced professional. At TSS, we make sure we fully understand our customer’s requirements so we can offer the highest level of performance within the given constraints. Our extensive experience in the ballistic barrier industry has given us the knowledge to offer the best solution that fits your needs, from government buildings to financial institutions to healthcare facilities.
Learn more about our ballistic glazing solutions by downloading our free Ballistic Glazing Solutions Guide.
Or, reach out to our experts, and we can help you harden your physical security.
We’re happy to get to know you and your needs to determine which products are appropriate for your application.