UL 10C Fire Test Explained How Door Hardware Must Perform

Introduction: Why UL 10C Matters for Fire Door Hardware

In fire-rated door assemblies, door hardware is not an accessory — it is a life-safety component. Hinges, locks, closers, and exit devices must continue to function under extreme fire exposure to ensure compartmentation, controlled egress, and fire containment.

UL 10C, officially titled “Positive Pressure Fire Tests of Door Assemblies”, is one of the most critical fire test standards for door hardware used in commercial and industrial buildings, especially in North America and UL-recognized markets.

This article explains:

• •What UL 10C really tests

• •How door hardware is evaluated under fire conditions

• •Performance requirements for each hardware category

• •How UL 10C integrates with ANSI/BHMA and UL 305 standards

• •Practical guidance for engineers, QC teams, and procurement professionals

What Is UL 10C Fire Test?

UL 10C evaluates the fire resistance performance of door assemblies under positive pressure conditions.

Unlike older neutral pressure fire tests, UL 10C simulates real fire behavior, where hot gases build pressure at the top of the opening and attempt to force flames through gaps.

Key Characteristics of UL 10C

• •Positive pressure furnace

• •Fire exposure up to 3 hours

• •Evaluates flame passage, temperature rise, and  structural integrity

• •Door hardware is tested as part of the complete door  assembly

Any hardware used on a fire-rated door must be listed for use with UL 10C assemblies.

Why Positive Pressure Testing Is Critical

In real fires:

• •Hot gases rise

• •Pressure builds at the upper section of doors

• •Flames exploit weak points around hinges, locks, and latch areas

UL 10C ensures that:

• •Hinges do not deform or fail

• •Locks maintain latch engagement

• •Closers continue to control door position

• •Exit hardware remains operational during evacuation

This makes UL 10C mandatory for most modern fire-rated commercial buildings.

UL 10C Performance Requirements by Hardware Type

1. Fire-Rated Door Hinges (UL 10C)

Critical Functions During Fire:

• •Maintain door alignment

• •Prevent leaf drop or warping

• •Support full door weight at elevated temperatures

UL 10C Evaluation Focus:

• •Material stability

• •Fastener retention

• •Load-bearing performance under heat

Certified Example:

• •D&D UL Series Door Hinges

• UL / cUL UL 10C Fire Rated 3 Hours

• File No. R38013

• ANSI/BHMA Grade 1 2,500,000 cycles & Grade 2 1,500,000 cycles

These hinges are suitable for heavy-duty commercial fire doors requiring both fire resistance and mechanical durability.

2. Fire-Rated Door Locks (UL 10C)

Critical Functions During Fire:

• •Keep the door latched

• •Prevent flame penetration through latch edge

• •Maintain compatibility with panic or exit devices

UL 10C Evaluation Focus:

• •Latch projection stability

• •Lock body deformation

• •Fire endurance with repeated heat cycles

Certified Example:

• •UL 10C Fire Rated Door Locks

• Fire Rating: 3 Hours

• File No. R40901

These locks are suitable for fire-rated egress doors, stairwells, and compartment doors.

3. Fire-Rated Door Closers (UL 10C)

Critical Functions During Fire:

• •Ensure door self-closes

• •Maintain closed position during fire

• •Prevent uncontrolled door swing

UL 10C Evaluation Focus:

• •Hydraulic system stability

• •Closing force retention

• •Mechanical integrity after fire exposure

Certified Example:

• •UL 10C Fire Rated Door Closers

• Fire Rating: 3 Hours

• File No. R40717

Fire-rated closers are essential for fire compartmentation compliance in accordance with building codes.

4. Fire Exit & Panic Hardware (UL 10C + UL 305)

Critical Functions During Fire:

• •Enable immediate egress

• •Operate under high heat

• •Prevent door obstruction or lock-up

Standards Involved:

• •UL 10C  – Fire resistance of the assembly

• •UL 305  – Panic hardware operational performance

Certified Examples:

• •Fire Exit Hardware

• UL 10C Fire Rated 3 Hours

• File No. R40486

• •Panic Hardware

• UL 305 Certified

• File No. SA45817

This combination ensures fire endurance + life safety egress compliance.

Relationship Between UL 10C and ANSI/BHMA Standards

UL 10C focuses on fire performance, while ANSI/BHMA evaluates mechanical durability and operational life.

For engineers and specifiers, dual compliance is essential:

• •UL 10C → Fire safety

• •ANSI/BHMA Grade 1 / 2 → Long-term durability

Engineering & Procurement Considerations

When specifying UL 10C hardware, professionals should verify:

✔ UL File Number (traceable listing)
✔ Fire rating duration (60 / 90 / 180 minutes)
✔ Compatibility with door type and rating
✔ ANSI/BHMA grade where applicable
✔ System-level compliance (hinge + lock + closer + exit device)

Fire-rated hardware must be evaluated as a system, not as individual components.

Common Misconceptions About UL 10C

❌ “Only the door leaf needs UL 10C”
✔ Hardware is equally critical

❌ “Fire-rated means heavy-duty only”
✔ Fire resistance and mechanical durability are separate requirements

❌ “UL mark alone is enough”
✔ File number and application scope must be verified

Conclusion: UL 10C as a Benchmark for Fire Door Hardware Performance

UL 10C is not just a certification label — it is a performance benchmark that defines how door hardware must behave when failure is not an option.

For engineers, QC teams, and professional buyers, selecting UL 10C-listed hardware with verified file numbers and system compatibility is essential for:

• •Code compliance

• •Fire compartment integrity

• •Occupant life safety

• •Project approval and inspection success

As a UL-listed door hardware manufacturer, D&D UL Series Hardware provides a complete, tested, and compliant solution for fire-rated door assemblies in demanding commercial applications.