The science of thermal conductivity explained: Understanding how fireproof fabrics respond to heat

Fire safety in public spaces depends on more than aesthetics or colour harmony. Behind every fireproof fabric lies a precise scientific principle that determines how it behaves when exposed to heat: thermal conductivity.

Understanding this concept is essential for professionals in the contract sector. For architects, interior designers, and specifiers, knowing how materials transfer heat can make the difference between safety and risk. It is also key to selecting the right textile solution that maintains both protection and beauty.

This article explores the science behind thermal conductivity, how heat moves through materials, and how flame-retardant fabrics developed by Dabedan are designed to combine performance, comfort, and design excellence.

What is thermal conductivity?

Thermal conductivity describes a material’s ability to transfer heat through its structure. It indicates how easily energy passes from one point to another when a temperature difference exists.

The unit of measurement is watts per metre per kelvin (W/m·K). This means the amount of heat that travels through a one-metre section of material for each degree of temperature difference.

Materials with high thermal conductivity quickly transmit heat, while those with low thermal conductivity resist its flow and act as insulators.

In textiles, understanding this property is essential to evaluate how flame-retardant fabrics behave in the presence of heat. Low-conductivity fabrics such as inherently flame-retardant polyester (PES FR) slow the heat transfer, giving occupants valuable extra seconds during an emergency and reducing the risk of ignition.

Heat transfer mechanisms

Heat moves through three main mechanisms: conduction, convection, and radiation. Each process plays a distinct role in determining the performance of fireproof fabrics under thermal stress.

Conduction

Conduction is the process by which heat passes directly through a material, molecule by molecule. When a hot surface comes into contact with a fabric, the heat energy flows from the warmer area to the cooler one.

Dense or tightly woven fireproof fabrics slow this process. The lower the thermal conductivity of the fibres, the more effectively the material blocks heat transfer. This is why inherently flame-retardant polyester fabrics are widely used in the contract and hospitality sector. Their molecular structure acts as a thermal barrier that limits temperature rise on the non-exposed side.

Convection

Convection occurs when heat is transferred by the movement of air or fluid. In textiles, it happens when air flows through or around the fabric surface. If air circulates freely, heat can spread faster.

To counteract this effect, high-performance fireproof fabrics are designed to control air permeability. By optimising the weave density and weight, the material reduces airflow and therefore slows down the convective transfer of heat.

Radiation

Radiation is the emission of energy in the form of electromagnetic waves. Unlike conduction or convection, it does not require a physical medium. This is the mechanism responsible for heat felt near an open flame or a radiant heater.

Certain textile finishes and lighter colours can help reflect part of the radiant energy, keeping the surface temperature lower and reducing the overall thermal load on the fabric.

Why thermal conductivity matters in fireproof fabrics

Thermal conductivity is not only a scientific property, it is a safety parameter that directly affects human protection and building performance.

In public spaces such as hotels, theatres, offices, or hospitals, the speed at which heat spreads can determine whether a fire remains contained or becomes uncontrollable.

Fabrics with low thermal conductivity delay heat propagation, giving fire suppression systems and evacuation procedures more time to act.

In addition, thermal performance ensures comfort and durability in daily use. A fabric that resists thermal stress will maintain its appearance, stability, and mechanical strength for longer periods.

Dabedan’s intrinsically flame-retardant fabrics are engineered so that their properties are part of the fibre itself rather than a surface treatment. This means that even after washing or prolonged exposure to sunlight and heat, the protection remains permanent.

Fibre type	Thermal conductivity	Heat durability	FR performance over time	Recommended use
PES FR (inherently flame retardant)	Low ⭐⭐	Excellent ⭐⭐⭐⭐	Permanent ✔️	Curtains, upholstery, acoustic panels
Treated natural fibres (FR cotton)	Medium ⭐⭐⭐	Limited ⭐⭐	Decreases with washing ✖️	Short-term decorative use
Technical blends (PES FR + others)	Low–medium ⭐⭐	Very good ⭐⭐⭐	Very stable ✔️	Hotels, auditoriums, public spaces

How fireproof fabrics behave under heat

When exposed to high temperatures, fireproof fabrics do not burn like conventional textiles. Instead, they undergo controlled physical and chemical transformations that prevent flame spread and structural collapse.

The reaction depends on the fibre type and its internal structure.

How fibres react to high temperatures and flames

• Inherently flame-retardant polyester (PES FR) fibres are self-extinguishing and do not support combustion. When exposed to heat, they melt slightly and carbonise, forming a compact barrier that blocks oxygen and prevents further flame spread.
• Natural fibres treated with chemical finishes (such as cotton FR): they can offer temporary resistance, but their performance may decrease over time due to washing or environmental exposure.
• Technical blends: combining different fibre types allows for a balance between comfort, strength, and safety, ideal for curtains and upholstery used in hotels and auditoriums.

This controlled reaction ensures that the fabric does not drip, spread, or produce excessive smoke, providing a safer environment in the event of fire.

Factors affecting heat resistance

The way a fireproof fabric resists heat is influenced by multiple external factors that can modify its thermal response.

Humidity

Moisture acts as a heat sink, absorbing energy before it evaporates. In humid environments, fabrics can retain heat longer, slightly changing their response to high temperatures. Proper ventilation and controlled humidity help maintain consistent fire performance.

Airflow and ventilation

Increased airflow enhances convection and accelerates heat distribution. This is why fire behaviour tests are carried out in controlled chambers, ensuring that the measured response reflects real-world safety performance.

Layering and fabric construction

Multi-layer fabrics or those with coatings improve insulation by trapping small air pockets that slow down heat transfer. Blackout fabrics, for example, often use double or triple layers to achieve both light control and high thermal resistance.

Thickness and fabric density

Heavier and denser fabrics provide better thermal protection. The structure of Dabedan’s velvet collections, for instance, contributes to excellent heat absorption and gradual dissipation. Their thickness acts as a natural barrier that reduces the temperature gradient across the surface.

Fabric composition and fibre type

Each fibre type has a specific thermal conductivity value. Flame-retardant polyester conducts less heat than natural or mineral fibres. Its protection remains stable over time because the molecular structure does not degrade with washing or ageing.

Key points for businesses for safety and fabric selection

For specifiers, interior designers, and contract managers, choosing the right fireproof fabric requires balancing aesthetics, comfort, and compliance. The decision should always consider thermal performance as a key factor in fire safety strategy.

How to select fabrics based on thermal performance

1. Verify certifications: the fabric must meet EN 13501-1 (B-s1, d0) or EN 13773 Class 1 for curtains, and EN 1021-1/2 or BS 5852 Crib 5 for upholstery.
2. Check the structure and weight: denser, heavier fabrics typically provide better thermal insulation.
3. Review the composition: prefer inherently fire-retardant fibres over treated ones for permanent protection.
4. Consider the final application: requirements differ between draperies, upholstery, and acoustic panels.
5. Request test reports: ask for detailed reaction-to-fire and thermal conductivity results to compare materials accurately.

Application	Best textile choice	Applicable standards	Reason
Hotels (Hospitality)	PES FR / Technical blends	EN 13773 Class 1 (curtains) · EN 13501-1 (B-s1,d0)	Permanent safety + durability under frequent use
Theatres / Auditoriums	Heavy FR velvets (stage curtains)	EN 13773 Cl.1 (drapes) · IMO · B-s1,d0	Heat + acoustic absorption with premium aesthetics
Offices / Corporate buildings	FR Sheers / Dimouts	EN 13773 Cl.1 (curtains) · EN 13501-1 (B-s1,d0)	Light control + compliance with EU safety rules
Temporary events	Economical treated FR fabrics	EN 13773 Cl.1 (temporary curtains)	Cost-effective for short use without durability needs

Compliance with UK fire safety regulations

In the United Kingdom, compliance is essential to ensure public safety in contract environments. Upholstery fabrics must comply with BS 5852 (Crib 5), which tests ignition resistance to simulated sources of heat. Curtains and sheers are assessed according to BS 5867 Part 2 Types B and C, evaluating how fabrics behave under flame contact and radiant heat.

Choosing certified fireproof textiles guarantees that spaces meet legal requirements and that the materials have undergone rigorous testing for performance and reliability.

How Dabedan supports innovation and fire safety in textiles

At Dabedan, we believe that innovation in flame-retardant fabrics begins with understanding the science behind them. By studying thermal conductivity and heat transfer, we design textiles that not only meet international safety standards but also enhance acoustic comfort, light control, and visual harmony.

Our collections are produced in Barcelona, using state-of-the-art weaving technology and European inherently flame-retardant polyester fibres that ensure long-term performance and traceability. Every fabric is tested according to EN 13501-1 and other international standards, confirming that Dabedan products offer certified fire safety without compromising beauty.

We collaborate closely with architects, interior designers, and contract professionals to help them select the right fabric for each project, ensuring both compliance and inspiration.

Safety and design can coexist beautifully. With Dabedan’s fabrics, every space becomes a place where innovation, comfort, and protection work together seamlessly.