Exploring UL levels 4 - 6

Security threats evolve quickly, and so must the materials designed to stop them. UL 752 levels 4 through 6 address the growing need for protection against rifles, submachine guns, and high-velocity handgun fire. Each UL level is built around a specific threat profile and tested under strict conditions to ensure real-world performance. The right rating provides more than compliance; it delivers protection tailored to the realities of the threat.

What Is UL 752?

UL 752 is a ballistic standard established by Underwriters Laboratories to define how materials should perform when exposed to firearm threats. The UL rating system is organized by the kind of weapon and ammunition used, with all classifications tied to a certain ballistic threat type. 

During testing, materials are shot from a distance of 15 feet and must prevent penetration, spall, or fragmentation from passing through. Such requirements are designed to reflect real-world conditions. They offer a trusted benchmark for selecting materials that protect people, assets, and secure environments from ballistic threats. This process ensures that when protection is needed most, the materials can deliver.

UL Level 4

Test Conditions

• Firearm: .30 caliber M1 Garand rifle

• Ammunition: 180-grain lead core soft point

• Velocity: Approximately 2,540 feet per second

• Rounds: 1, fired at 15 feet

Protective Capabilities

Designed as the entry point into rifle-rated protection, UL level 4 counters the force of .30 caliber rounds capable of breaching materials built for handguns. These projectiles generate higher impact energy and deeper penetration. As a result, this UL level is suitable where long-gun threats present a genuine risk.

Realistic Threat Profile

• Hunting rifles in civilian scenarios

• Older military surplus firearms

• Spontaneous rifle fire in civil unrest or active shooter events

Common Applications

• Police substation entry points

• Courthouses and city administration offices

• Public-facing government lobbies

Compatible Materials

• Ballistic steel panels: Reliable and durable, commonly used in wall retrofits and armored enclosures

• Fiberglass composite panels: Lighter and easier to install in wall systems, often used behind drywall

• Laminated ballistic glass: Transparent protection for windows or transaction areas using glass-polycarbonate layers

Benefits

• Easier to retrofit into existing structures compared to higher UL levels

• Offers a strong defense without excessive material weight

UL Level 5

Test Conditions

• Firearm: .308 Winchester (150-grain) or 7.62x51mm NATO

• Ammunition: 150-grain full metal copper jacket military ball

• Velocity: Approximately 2,750 feet per second

• Rounds: 1, fired at 15 feet

Protective Capabilities

Facilities at heightened risk from military-style rifle fire require protection beyond standard ballistic materials. UL level 5 is engineered to stop the 7.62x51 mm NATO (.308 Winchester) round, a cartridge found in rifles used by law enforcement and the military. The round’s greater kinetic force and penetration depth underscore the importance of UL level 5 in environments where rifle attacks are a tangible concern.

Realistic Threat Profile

• Coordinated attacks involving military-style rifles

• Urban threats from organized crime or gang activity

• Security breaches at sensitive government facilities or critical infrastructure sites

Common Applications

• Military recruiting centers

• Law enforcement command and evidence rooms

• Data centers, telecom hubs, and power grid control buildings

Compatible Materials

• AR500 or AR600 steel: High-strength ballistic-grade steel used for structural or panelized protection

• Hybrid composite panels: Layered materials combining fiberglass, ceramics, and polymers for weight reduction

• Ballistic-rated glass systems: Laminated assemblies capable of absorbing rifle-level impact at secure points of entry

Benefits

• Supports continuity of operations in high-risk environments, such as law enforcement and critical infrastructure

• Reduces long-term liability and increases stakeholder confidence in security planning

UL Level 6

Test Conditions

• Firearm: 9mm submachine gun (e.g., Uzi or MP5)

• Ammunition: 124-grain Full Metal Jacket (FMJ)

• Velocity: Approximately 1,400 feet per second

• Rounds: 5, fired at 15 feet

Protective Capabilities

Unlike the rifle-focused levels, UL level 6 responds to high-speed, close-range attacks involving multiple 9mm shots from submachine guns or enhanced handguns. It accounts for scenarios where attackers use rapid-fire weapons in confined or crowded areas, raising the need for materials that can absorb repeated, fast-paced impacts.

Realistic Threat Profile

• Rapid-fire handgun assaults

• Submachine gun use during robberies or close-quarters attacks

• Modified civilian handguns firing high-pressure (+P) rounds

Common Applications

• Secure reception areas in urban buildings

• Ticketing booths and kiosks in transit hubs

• Cash-heavy retail or jewelry storefronts

Compatible Materials

• Polycarbonate-glass laminates: Transparent systems used in lobbies, booths, and transaction windows

• Ballistic fiberglass panels: Lightweight and ideal for high-traffic walls or desk enclosures

• Aluminum composite panels: Corrosion-resistant and often used in prefabricated security kiosks or tight spaces

Benefits

• Delivers a strong defense without the weight or complexity of rifle-rated systems

• Easily integrated into retrofits, especially in urban or retail settings

Strengthening Every Barrier with UL Level Standards

UL Levels 4 - 6 deliver targeted ballistic protection for environments facing elevated threats. Instead of overengineering or falling short, the UL levels offer a strategic balance between defense, cost, and constructability. Whether securing government lobbies, utility hubs, or commercial entryways, choosing the right level of defence reinforces safety where it's needed most. At Action Bullet Resistant, we provide materials tested to perform in real conditions. Let’s work together to bring reliable security to everyday spaces.

FAQ:

1) What do UL 752 Levels 4–6 cover?

Levels 4–6 address threats that exceed typical handguns: Level 4 (.30 cal rifle), Level 5 (7.62×51mm / .308), and Level 6 (5 shots of 9mm at higher velocity, often SMG).

2) Are UL levels cumulative?

No. UL 752 levels are tested independently. Passing one level does not imply passing another.

3) What does Level 4 protect against?

Level 4 counters a .30 cal M1 Garand rifle round (180-gr soft point). It’s the entry point into rifle-rated protection for spaces where long-gun threats are credible.

4) Typical Level 4 use cases?

Police substations, courthouses/city offices, and government lobbies where a higher-energy rifle threat is plausible.

5) What does Level 5 protect against?

Level 5 is tested with .308 Win / 7.62×51mm NATO (150-gr FMJ)—a high-energy rifle round used in military/law-enforcement platforms.

6) Typical Level 5 use cases?

Recruiting centers, LE command/evidence rooms, data/telecom hubs, and grid control facilities where continuity of operations is critical.

7) What does Level 6 protect against?

Level 6 addresses multiple 9mm shots (5 rounds, ~1,400 fps), representative of submachine guns or enhanced handguns in close quarters.

8) Typical Level 6 use cases?

Urban reception areas, transit ticketing/kiosks, cash-intensive retail/jewelry—places exposed to rapid-fire handgun/SMG threats.

9) How are Levels 4–6 tested?

All shots are fired from 15 ft under controlled velocity. Passing requires no penetration and hazardous spall containment on the safe side.

• L4: 1 shot (.30 cal, ~2,540 fps)

• L5: 1 shot (7.62×51mm, ~2,750 fps)

• L6: 5 shots (9mm, ~1,400 fps)

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10) What materials are commonly used?

Ballistic steel or fiberglass composite panels for opaque areas; laminated/glass-polycarbonate glazing for vision zones; hybrid composites (ceramic/UHMWPE) where weight reduction matters.

11) Can these be retrofitted?

Yes. Many Level 4–6 solutions are designed to fit behind drywall/casework or into standard frames, minimizing downtime.

12) How do I choose among Levels 4–6?

Match to your threat profile and mission risk:

• L4: credible long-gun risk (entry rifle).

• L5: higher-energy 7.62 NATO rifle threat.

• L6: rapid-fire 9mm in close-quarters, multi-hit scenarios