Engineering Fundamentals | PA-EF-006
Active-Shooter Glazing Explained
The term active-shooter glazing is increasingly used to
describe security glazing systems intended to help protect building
openings during an armed attack.
Overview
But the term can be misleading.
An active-shooter glazing system does
not necessarily stop bullets.
Some systems are designed and tested for ballistic resistance.
Others are designed to remain an effective forced-entry barrier
after gunfire has weakened the glazing and surrounding
fenestration system
.
Still others may be engineered and tested to provide both ballistic
and forced-entry protection.
Understanding these distinctions is critical when evaluating or
specifying glazing for active-shooter security applications.
What Does “Active-Shooter Glazing” Actually Mean?
Active-shooter glazing is not, by itself, a ballistic
performance rating.
It is better understood as a broad description of glazing or
fenestration systems intended to address threats associated with
an armed attacker.
The actual protection provided depends on the performance standard,
test method, system construction, and specific rating achieved.
A system marketed for active-shooter protection might be designed to:
- Resist forced entry after being weakened by gunfire
- Resist a defined ballistic threat
- Provide both ballistic and forced-entry resistance
- Maintain a barrier long enough to delay access to occupants or
protected areas
These are not the same performance claims.
Engineering Principle
The phrase active-shooter glazing does not define the
protection level. The applicable test standard and demonstrated
performance do.
Why Combine Gunfire and Forced Entry?
An armed attacker may not need to pass physically through the
glazing itself.
Gunfire can be used to damage the glass, frame, glazing stops,
hardware, or other parts of an opening before the attacker attempts
to force a path through the weakened system.
This creates a different security problem than conventional
ballistic protection alone.
The objective may be to keep the opening functioning as a barrier
after it has already sustained ballistic damage.
That is the principle behind active-shooter forced-entry testing.
Understanding ASTM F3561
ASTM F3561 was developed to evaluate the forced-entry resistance
of fenestration systems after simulated active-shooter weakening.
The test uses firearm impacts to weaken specified areas of the
system before mechanical impacts are applied.
An important point is that
ASTM F3561 is not a ballistic-resistance standard.
Projectile perforation is permitted during the weakening portion
of the test. The purpose of the gunfire is to simulate damage that
could occur before an attacker attempts to physically breach the
opening.
The subsequent forced-entry portion evaluates whether the damaged
system can continue resisting the creation of an opening.
This means a system can successfully meet an ASTM F3561 requirement
without being bullet-resistant.
That distinction should be clearly understood whenever ASTM F3561
performance is specified or discussed.
Ballistic Weakening Is Not Ballistic Resistance
The difference can be summarized simply:
Ballistic Weakening
Gunfire is used to damage the system before forced-entry testing.
Ballistic Resistance
The system is required to resist penetration by a specified
projectile threat under an applicable ballistic test method.
The presence of firearm impacts in a test does not automatically
make that test a ballistic-resistance test.
This is one of the most important concepts when evaluating
active-shooter glazing.
What If Ballistic Protection Is Also Required?
Some projects require more than forced-entry delay after ballistic
weakening.
They may also require the glazing to resist projectile penetration.
In that case, the system should satisfy the applicable ballistic
requirement in addition to the applicable
forced-entry requirement.
For example, a project might require performance against a specified
UL 752 ballistic level together with forced-entry performance under
ASTM F3561.
The requirements address different aspects of the threat:
Ballistic requirement:
resist the specified projectile threat.
Forced-entry requirement:
maintain the integrity of the opening against the defined physical
attack.
When both are required, both should be independently demonstrated.
Why the Complete Fenestration System Matters
Active-shooter security is not only about the center of the glass.
An attacker can attempt to defeat:
- Glazing
- Frames
- Glazing stops
- Mullions
- Door hardware
- Locks
- Hinges
- Anchors
- Connections to the surrounding structure
Gunfire can also damage components that might otherwise provide
adequate forced-entry resistance.
For this reason, active-shooter forced-entry testing is particularly
concerned with the
complete fenestration assembly.
A high-performance laminate cannot compensate for a frame, door,
hardware system, or anchorage condition that cannot maintain the
required barrier.
The Role of Laminated Glass
Laminated glazing is particularly valuable in forced-entry
applications because the glass can fracture while the bonded
assembly remains in place.
Interlayers retain fractured glass and help maintain continuity
after impact.
During an active-shooter forced-entry event, the laminate may
already contain extensive ballistic damage before the physical
attack begins.
The interlayer system must therefore continue helping the damaged
glazing resist:
- Tearing
- Displacement
- Penetration
- Repeated impact
- Creation of an opening
This is why the behavior of the laminate
after glass fracture is so important.
Delay Is the Security Objective
For forced-entry active-shooter systems, the purpose is generally
not to make an opening permanently impenetrable.
The objective is to delay access.
Additional time may allow:
- Occupants to move away from the threat
- Doors or secure areas to be locked down
- Emergency procedures to be implemented
- Security personnel to respond
- Law enforcement to arrive
This concept of delay is central to forced-entry security.
However, a standardized test rating should not automatically be
translated into a guaranteed real-world delay time. Actual attacks
can differ substantially from laboratory test conditions.
Where Active-Shooter Glazing May Be Used
Active-shooter security systems may be considered for:
- Schools and educational facilities
- Government buildings
- Courthouses
- Healthcare facilities
- Corporate facilities
- Public buildings
- Critical infrastructure
- Secure vestibules
- Entry doors
- Storefront systems
- Interior secure zones
The appropriate level and type of protection should be based on the
threat assessment and project requirements rather than on the
building category alone.
Active-Shooter Protection Can Be Layered
Not every opening within a building necessarily requires the same
protection.
A security strategy may use different levels or types of glazing
at different locations.
For example, the design might prioritize:
- Exterior entrances
- Vestibules
- Main access doors
- Interior secure zones
- Administrative areas
- High-occupancy spaces
- Areas used for shelter or lockdown
Some locations may require forced-entry resistance.
Others may require ballistic protection.
Higher-risk openings may require both.
This allows glazing to become part of a broader
layered security strategy rather than being treated
as a stand-alone solution.
Glazing Is Only One Part of the Security Strategy
Even a highly resistant fenestration system cannot eliminate every
risk associated with an armed attack.
Security glazing should be considered alongside:
- Access control
- Door and hardware design
- Building layout
- Surveillance
- Communication systems
- Emergency procedures
- Secure areas
- Response planning
- Other physical-security measures
The purpose of security glazing is to contribute to the overall
protection strategy by maintaining barriers, resisting defined
threats, and creating time.
Selecting an Active-Shooter Glazing System
The first question should not be:
“Is this active-shooter glass?”
A better set of questions is:
- What threat is the system expected to resist?
- Is ballistic resistance required?
- Is forced-entry resistance required?
- Are both required?
- Which test standards apply?
- What rating or level is required?
- Was the glazing tested alone or as part of the complete
fenestration system? - What frame, hardware, and anchorage are required?
- What opening size and configuration were evaluated?
- Are there additional requirements for spall, optics, thermal
performance, or durability?
These questions reveal much more about the actual protection
provided than the product label alone.
A Simple Comparison
| Consideration | Ballistic-Resistant System | Active-Shooter Forced-Entry System | Combined System |
|---|---|---|---|
| Gunfire Used? | Yes | Yes, for weakening | Yes |
| Required to Stop Projectile? | Yes, according to specified ballistic requirement | Not necessarily | Yes, according to specified ballistic requirement |
| Forced-Entry Attack Evaluated? | Not necessarily | Yes | Yes |
| Primary Objective | Resist specified projectile threat | Maintain barrier after ballistic weakening | Resist projectile threat and subsequent/required forced-entry attack |
| Example Standard | UL 752 | ASTM F3561 | Applicable ballistic standard + ASTM F3561 |
Key Takeaways
- “Active-shooter glazing” is not, by itself, a performance
rating.
- An active-shooter glazing system does not necessarily stop bullets.
- ASTM F3561 evaluates forced-entry resistance after simulated
active-shooter weakening. - Ballistic weakening and ballistic resistance are not the same
thing.
- If projectile resistance is required, an applicable ballistic
rating should also be specified. - Systems can be engineered and evaluated to provide both ballistic
and forced-entry protection. - The frame, hardware, anchorage, and surrounding fenestration
system are critical to active-shooter forced-entry performance. - Laminated glazing can remain an effective barrier even after
extensive glass fracture. - Forced-entry protection is fundamentally about
creating delay and maintaining a barrier. - Active-shooter glazing should be part of a broader layered
security strategy. - The applicable standards and demonstrated performance matter
more than the product label.
Continue Learning
- PA-EF-002 — What Is Forced-Entry Resistant Glass?
Learn how laminated glazing can remain an effective barrier after
repeated physical attack. - PA-EF-005 — Bullet-Resistant vs. Forced-Entry Resistant Glazing
Compare the different threats, engineering objectives, and testing
approaches behind ballistic and forced-entry systems. - PA-TS-001 — Understanding UL 752
Learn how ballistic-resistant equipment is evaluated against
defined projectile threats. - PA-TS-003 — Understanding ASTM F3561
Take a deeper look at the test method used to evaluate forced-entry
resistance after simulated active-shooter weakening. - PA-ED-001 — How Engineers Design Security Glazing Systems
Explore how threat, materials, framing, environment, optics, and
other requirements are balanced within a complete security system.
