EN 1634 Fire Door Testing: What Happens to Hinges and Locks During the Test?

Introduction: Fire Testing Is a Stress Test for Door Hardware

In fire-resisting door assemblies, hinges and locks are not passive components.
During an EN 1634-1 fire resistance test, these components are subjected to extreme thermal, mechanical, and structural stresses that go far beyond normal service conditions.

Understanding what actually happens to hinges and locks during the test is essential for:

• *Fire door engineers

• *QC and technical auditors

• *Hardware specifiers

• *Manufacturers validating fire-rated performance

This article explains how EN 1634-1 evaluates hinges and locks, what failure modes are monitored, and how test results influence real-world specification.

Overview of EN 1634-1 Fire Door Testing

EN 1634-1 is the European standard for determining the fire resistance of door and shutter assemblies.

Key Test Parameters

• *Furnace temperature follows ISO 834 time–temperature curve

• *Test duration typically 30 / 60 / 90 / 120 minutes

• *Door assembly mounted in a vertical furnace

• *Fire exposure from one side only

Hardware is tested installed in its final position, using:

• *Production materials

• *Approved fasteners

• *Installation instructions identical to site conditions

Test Sequence: What Happens Step by Step

Phase 1: Initial Exposure (0–10 Minutes)

Thermal Shock Begins

• *Furnace temperature rises rapidly to ~680°C

• *Hinges and locks experience instant thermal expansion

• *Differential expansion occurs between:

• Steel hardware

• Timber or composite door core

• Intumescent materials

Engineering Observation:

• *Poor material matching causes early distortion

• *Incorrect screw types may loosen

Phase 2: Structural Loading (10–30 Minutes)

Door Weight Transfers to Hinges

• *Door leaf begins to warp toward the fire side

• *Gravity load shifts unevenly across hinge knuckles

• *Upper hinge becomes critical

Hinge Behavior Under Test:

• *Knuckle deformation

• *Pin elongation

• *Fastener shear stress

Failure Indicators:

• *Excessive door drop

• *Hinge leaf pull-out

Phase 3: Latching System Under Fire (20–60 Minutes)

Locks Become the Primary Fire Barrier

• *Door tries to bow away from the frame

• *Latch bolt resists forced separation

• *Lock case exposed to sustained high temperature

Lock-Specific Observations:

• *Latch projection stability

• *Spring degradation

• *Lock body distortion

Critical Failure Mode:

• *Latch retraction or loss of engagement → Integrity failure (E)

Phase 4: Advanced Fire Exposure (60–120 Minutes)

System Survival Phase

• *Metal temperatures exceed 800°C

• *Non-metallic components are fully degraded

• *Hardware relies purely on metal mass and geometry

Key Monitoring Points:

• *Continuous attachment of hinges

• *Door remains closed

• *No sustained flaming on unexposed side

Integrity Criteria: How Hinges and Locks Are Evaluated

Under EN 1634-1, hardware is assessed indirectly via door integrity (E).

Integrity failure occurs if:

• *Flames penetrate through gaps

• *Cotton pad ignition occurs

• *Hardware detachment causes openings

Important Note:
EN 1634-1 does not require post-fire operability of hinges or locks.

Common Failure Modes Observed in Testing

Hinges

• *Insufficient material thickness

• *Low-grade steel losing strength

• *Inadequate screw embedment depth

Locks

• *Latch spring collapse

• *Thin lock cases deforming

• *Incompatible intumescent protection

Engineering Design Factors That Influence Test Results

Material Selection

• *Stainless steel vs carbon steel

• *Melting point and yield strength retention

Geometry

• *Hinge knuckle diameter

• *Pin engagement length

• *Lock case wall thickness

Installation

• *Screw type and grade

• *Reinforcement plates

• *Door edge preparation

Fire Door Assembly Dependency

A critical principle of EN 1634-1:

Hardware is approved only in the tested configuration.

Changes in:

• *Hinge size

• *Screw material

• *Lock model

• *Door core density

may invalidate fire test evidence.

EN 1634-1 vs Real-World Expectations

Aspect	EN 1634-1 Requirement
Door remains closed	Yes
Hinges remain attached	Yes
Lock remains latched	Yes
Post-fire usability	Not required

This distinction is important for project specification clarity.

Practical Guidance for Engineers & Specifiers

✔ Select hinges tested for door weight + fire duration
✔ Verify lock latch design under fire conditions
✔ Avoid substitutions not covered by test evidence
✔ Cross-check EN 1935 fire grade compatibility

EN 1634-1 Is a Hardware Stress Test by Design

EN 1634-1 fire testing pushes hinges and locks to their physical and structural limits.

While the standard focuses on assembly integrity, the performance of hinges and locks often determines whether a fire door:

• *Holds its position

• *Prevents flame passage

• *Achieves its certified rating

• 
  

For fire-rated door systems, hardware engineering is fire engineering.

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