Table of Contents

1. Introduction: Perlite Filled Core and Fire Door Fire Protection

2. Overview of Perlite Filled Core as Fire Door Core Material

3. Insulation Mechanism of Perlite Filled Core: Core Principles

4. Key Performance Indicators: Fire Resistance Temperature and Thermal Conductivity

5. Expansion Sealing: The Core of Perlite Filled Core’s Fire Barrier Function

6. Performance Comparison Table of Perlite Filled Core and Other Fire Door Core Materials

7. Industry Data and Market Insights

8. Frequently Asked Questions (FAQs)

1. Introduction: Perlite Filled Core and Fire Door Fire Protection

Fire door core material is the core component determining the fire resistance and insulation performance of fire doors.

It acts as a key fire barrier, preventing the spread of fire and smoke, and protecting evacuation routes and property safety.

Perlite filling has become one of the most widely used fire door core materials in the industry.

Its unique insulation mechanism, excellent fire resistance temperature, low thermal conductivity, and expansion sealing performance make it an ideal choice for high-performance fire doors.

Understanding its working principle and key performance indicators is crucial for selecting and applying fire door core materials correctly.

2. Overview of Perlite Filled Core as Fire Door Core Material

Perlite filled core is made of expanded perlite, a natural volcanic glass, combined with inorganic binders and additives.

It is processed through mixing, pressing, and curing, forming a lightweight, porous, and non-combustible core material.

2.1 What is Perlite Filling for Fire Door Core

Perlite filling refers to the process of using expanded perlite as the main raw material to fill the inner cavity of fire doors.

Expanded perlite is produced by heating natural perlite ore to 800-1200℃, which causes it to expand 7-15 times and form a porous honeycomb structure.

This structure gives the perlite filled core excellent insulation and fire resistance properties.

2.2 Core Characteristics of Perlite Filled Core

Perlite filled core is non-combustible, reaching Class A1 fire resistance rating according to GB8624-2006 standard.

It is lightweight, with a bulk density of 250-300 kg/m³, reducing the overall weight of fire doors.

It has good thermal stability, no toxic gas release when exposed to fire, and meets environmental protection requirements.

3. Insulation Mechanism of Perlite Filled Core: Core Principles

The insulation mechanism of perlite filled core is closely related to its porous structure and material properties.

It mainly relies on three ways to block heat transfer, forming an effective thermal insulation barrier.

3.1 Porous Structure Blocks Heat Conduction

The expanded perlite particles have a large number of closed pores, accounting for 70%-80% of the total volume.

Air is enclosed in these pores, and air has extremely low thermal conductivity, which can effectively block heat conduction.

This is the most important part of the insulation mechanism of perlite filled core.

3.2 Inorganic Material Inhibits Heat Radiation

Perlite filled core is made of inorganic materials, which have good heat resistance and do not absorb or radiate heat easily.

When exposed to high temperatures, the inorganic components do not melt or decompose, maintaining the integrity of the insulation structure.

This inhibits the transfer of heat radiation, further enhancing the insulation effect.

3.3 Reduces Heat Convection

The dense porous structure of perlite filled core slows down the flow of air inside the core material.

This reduces heat convection, preventing high-temperature air from passing through the core material quickly.

It works with heat conduction and radiation blocking to form a comprehensive insulation system.

4. Key Performance Indicators: Fire Resistance Temperature and Thermal Conductivity

Fire resistance temperature and thermal conductivity are the two most critical performance indicators of perlite filled core.

They directly determine the insulation effect and fire resistance level of the fire door.

4.1 Fire Resistance Temperature of Perlite Filled Core

The fire resistance temperature of perlite filled core can reach above 1100℃, and its continuous use temperature is 600-800℃.

When exposed to high temperatures up to 1300℃, it still maintains structural stability without melting or collapsing.

This high fire resistance temperature ensures that the perlite filled core can act as a reliable fire barrier in severe fire conditions.

4.2 Thermal Conductivity of Perlite Filled Core

The thermal conductivity of perlite filled core is between 0.035-0.076 W/(m·K), which is much lower than that of ordinary building materials.

The exact value varies slightly according to the bulk density and particle size of the core material.

A lower thermal conductivity means better insulation performance, which can effectively reduce heat transfer through the fire door.

5. Expansion Sealing: The Core of Perlite Filled Core’s Fire Barrier Function

Expansion sealing is a unique performance of perlite filled core, which is crucial for enhancing its fire barrier effect.

It solves the problem of fire and smoke penetration caused by gaps in fire doors during high-temperature conditions.

5.1 Principle of Expansion Sealing

When the perlite filled core is exposed to high temperatures above 300℃, it undergoes a slight expansion, with an expansion rate of 3%-5%.

This expansion fills the gaps between the core material and the door frame, as well as the internal gaps of the core material.

It forms a dense sealing layer, preventing the penetration of fire and smoke, and ensuring the integrity of the fire barrier.

5.2 Role of Expansion Sealing in Fire Protection

Without expansion sealing, gaps in fire doors will become channels for fire and smoke spread.

The expansion sealing performance of perlite filled core can effectively block these channels, extending the fire resistance time of fire doors.

It works with the insulation performance to form a dual protection, maximizing the fire protection effect of fire doors.

6. Performance Comparison Table of Perlite Filled Core and Other Fire Door Core Materials

The following table compares the key performance indicators of perlite filled core with other common fire door core materials, based on industry test data and standards:

7. Industry Data and Market Insights

The global perlite market size reached approximately USD 3.71 billion in 2024, and is expected to grow to USD 5.01 billion by 2031, with a CAGR of 4.4%.

Fire door core material is one of the main application fields of perlite, accounting for about 35% of the total perlite application market.

A 2025 industry survey shows that perlite filled core accounts for 48% of the global fire door core material market, ranking first.

In European and North American markets, more than 60% of high-performance fire doors use perlite filled core as the core material.

The thermal conductivity of perlite filled core has decreased by 12% in the past 5 years, thanks to the improvement of processing technology.

The new fire door standard EN 1634-1 requires that the fire resistance temperature of core materials must be above 1000℃, which further promotes the application of perlite filled core.

8. Frequently Asked Questions (FAQs)

Q1: What is the main raw material of perlite filled core for fire doors?

A1: The main raw material is expanded perlite, which is made by heating natural perlite ore to 800-1200℃ for expansion. It is combined with inorganic binders and additives to form the final core material.

Q2: How does the thermal conductivity of perlite filled core affect the insulation effect of fire doors?

A2: Thermal conductivity is inversely proportional to the insulation effect. The lower the thermal conductivity (0.035-0.076 W/(m·K) for perlite filled core), the better the insulation effect, which can effectively block heat transfer.

Q3: What is the role of expansion sealing in perlite filled core?

A3: Expansion sealing fills the gaps between the core material and the door frame at high temperatures (300℃ above), forming a dense sealing layer. It prevents fire and smoke penetration, enhancing the fire barrier effect.

Q4: Does perlite filled core meet international fire safety standards?

A4: Yes. It meets the requirements of international standards such as EN 1634-1 and UL 10C, with Class A1 fire resistance rating and fire resistance temperature above 1100℃, fully complying with global fire safety regulations.

Q5: Compared with rock wool core, what are the advantages of perlite filled core?

A5: Perlite filled core has higher fire resistance temperature, better expansion sealing performance, and similar thermal conductivity. It is also more environmentally friendly, with no harmful substances released when exposed to fire.