Fire protection seals

Fire protection seals perform a central safety function in technical installations, machinery and structural penetrations. They form a safety-relevant barrier that effectively limits the spread of fire, smoke and hot gases to adjacent areas in the event of a fire. As a result, they make a significant contribution to the protection of people, installations and property and are a permanent component of modern fire protection concepts in industry, engineering and construction. The decisive factor is the choice of a suitable sealing material that reliably withstands the thermal, mechanical and normative requirements.

Requirements for fire protection seals

Seals in fire protection are subject to significantly higher requirements than conventional seals. While conventional seals are primarily intended to seal against media, fire protection seals must maintain their function even under extreme thermal conditions.

The focus is in particular on:

• High temperature resistance over defined periods of time, often several hundred to over a thousand degrees Celsius
• Low smoke and gas permeability, since flue gases represent one of the greatest hazards in the event of a fire
• Shape and functional stability despite exposure to heat, pressure load and material stresses
• Defined material behaviour in the event of a fire, such as non-flammable, self-extinguishing or specifically intumescent
• Compliance with standards in accordance with applicable fire protection, building or industrial requirements

Depending on the area of application, chemical resistance, ageing stability, compressive strength as well as installation and maintenance requirements also play an important role.

Classification of fire protection seals

Fire protection seals can fundamentally be distinguished by their mode of action. This classification is decisive for selecting the right material.

Passive fire protection seals consist of temperature-resistant materials that retain their sealing effect even under intense heat. They barely change their structure and act through their material properties.

Reactive fire protection seals contain intumescent components. These react to heat by greatly increasing their volume. In this way, gaps, joints or penetrations are actively closed in the event of a fire.

Which variant is used depends on the required protection level, the installation situation and the respective fire protection and fire resistance class.

Suitable sealing materials at a glance

Graphite-based seals

Graphite-based seals are among the most frequently used solutions in industrial fire protection. Pure or expanded graphite offers very high temperature resistance and remains dimensionally stable even under extreme thermal loads.

In addition, graphite is characterised by low gas and smoke permeability. As a result, this material is particularly suitable for applications where, in addition to fire resistance, tightness against aggressive media is required.

Graphite seals are found above all in industrial installations, flange connections, exhaust systems and technical partitions with high thermal requirements.

Mineral fibre and ceramic fibre materials

Mineral fibre and ceramic fibre materials are regarded as classic materials in preventive fire protection. They are generally non-flammable and retain their structural stability even at very high temperatures.

These materials are frequently used in the form of mats, sheets or sealing cords. Typical applications are structural partitions, fire dampers as well as cable and pipe penetrations.

Their advantage lies in their high fire resistance, while their mechanical flexibility is limited compared with elastomers.

Intumescent materials

Intumescent seals have the property of specifically foaming up when exposed to heat. In the process, the volume of the material increases many times over, reliably closing openings and joints.

This active protective effect makes intumescent materials particularly suitable for penetrations, joints and gap seals in structural fire protection. They are frequently used where components may deform or movements may occur in the event of a fire.

High-temperature elastomers

High-temperature elastomers combine a certain flexibility with increased temperature resistance. They are used where mobility, vibrations or ease of installation are required.

In direct comparison with mineral or graphite-based materials, their maximum temperature resistance is lower. They are therefore suitable above all for applications with moderate fire protection requirements or as a supplementary component within a fire protection system.

Typical areas of application

Fire protection seals are used in a wide variety of technical and structural applications. Typical areas of application are:

• Cable and pipe penetrations in buildings and industrial installations
• Machine housings, control cabinets and installation cladding
• Ventilation, air-conditioning and smoke extraction systems
• Doors, gates, dampers and partition systems
• Installations in the chemical, energy and process industries

Depending on the area of application, the requirements for temperature resistance, sealing effect, mechanical load capacity and approval vary considerably.

Selection criteria for the right sealing material

The selection of the suitable sealing material is a central factor for the effectiveness of fire protection. Several criteria should be assessed systematically:

• Required fire protection and fire resistance class
• Maximum service temperature in normal operation as well as in the event of a fire
• Mechanical load, movements and installation situation
• Contact with media such as gases, oils or chemicals
• Specifications from standards, building approvals and project-specific requirements

Particularly in safety-relevant applications, materials engineering advice is recommended in order to avoid wrong decisions.

Standards, tests and approvals

Depending on the area of application, fire protection seals are subject to different standards, directives and test procedures. These include fire resistance tests, smoke tightness tests as well as building authority or industrial approvals.

The specific design must always comply with the project-specific specifications, since only tested and approved systems guarantee the required protective effect.

Common mistakes in material selection

In practice, the following problems frequently occur:

• Use of temperature-resistant but flammable materials
• Insufficient consideration of smoke gas tightness
• Missing or unsuitable approvals
• Incorrect dimensioning of the seal in the event of a fire

These mistakes can considerably impair the protective effect.

Summary

Fire protection seals fulfil a safety-relevant function in industry, engineering and construction. In the event of a fire, they prevent the spread of fire, smoke and hot gases and thus make a significant contribution to the protection of people, installations and buildings. Decisive for the effectiveness is the selection of a sealing material that reliably meets both the thermal loads and the normative specifications.

Depending on the application, different material concepts are used. Graphite-based, mineral and intumescent materials offer high fire resistance values, while high-temperature elastomers enable additional flexibility. The decisive factors are always the area of application, the required fire protection class, the installation situation as well as tested approvals.

Careful material selection and professional design are central prerequisites for effective and standards-compliant fire protection.

FAQ – Fire protection seals

What distinguishes fire protection seals from normal seals?

Fire protection seals are designed for behaviour in the event of a fire and fulfil defined requirements for fire and smoke protection over specified periods of time.

Which materials are considered particularly suitable for fire protection?

Mineral materials, graphite-based materials and intumescent systems offer high fire resistance values and stable sealing properties.

Can elastomer seals be used in fire protection?

Special high-temperature elastomers with tested fire protection properties are suitable for applications with an additional need for flexibility.

What is the significance of standards and tests?

Standards and tests ensure the performance of fire protection seals under realistic fire conditions and are the basis for approvals.

How long must fire protection seals withstand in the event of a fire?

The resistance duration depends on the required fire resistance class and is frequently 30, 60 or 90 minutes.

Can fire protection seals be individually adapted?

Application-specific fabrication is possible provided that the material, dimensions and installation method comply with the tested system specifications.

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