Intumescent Paint for Steel – Advanced Fire Protection Coating Systems

Protect structural steel with high-performance intumescent paint for steel designed to provide certified fire resistance, durability and aesthetic finish.

In collaboration with Rudolf Hensel GmbH, we offer fully compatible intumescent coating systems that combine proven fire protection expertise with high-performance coating technology that includes corrosion protection as well as aesthetic appearance. Our intumescent paint systems for steel are specifically developed for demanding construction and infrastructure projects, including commercial buildings, industrial facilities and data centres.

Have a project in mind? Our experts will help you to find the optimal project-specific coating solution.

Contact our intumescent coatings experts

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What is Intumescent Paint for Steel?

Intumescent paint for steel is a passive fire protection coating that expands when exposed to heat, forming an insulating char layer that delays temperature rise in steel structures.

How intumescent coatings work

When exposed to fire:

  • The coating expands up to 50x its original thickness.
  • Forms a protective insulating char layer.
  • Reduces heat transfer to the steel.
  • Delays structural failure.

This makes intumescent paint steel systems essential for:

  • Structural steel in buildings.
  • Industrial facilities.
  • Infrastructure projects.

Intumescent Paint Systems for Steel

We are offering a range of intumescent paint systems for steel designed for different fire ratings, environments and application methods.

Teknos coating systems capabilities

  • Fire resistance: From R15 up to R180.
  • Application: Shop-applied and site-applied.
  • Substrates: Carbon steel and galvanised steel.
  • Environment: Indoor and outdoor.
  • Properties: Waterborne, solvent-free and solvent-borne.
  • Finish: From industrial grade to architectural level

Intumescent coating systems for on-site and shop application

The intumescent coating systems shown below represent proven fire protection coating solutions for typical on-site and off-site applications. These systems are ideally suited for steel structures like in data centres, but can be used for other projects, as well. Please contact our technical experts for individual coating requests.

For detailed information on surface preparation, approvals, application guidance, and technical documentation, please download the documents below the systems.

Designed for on-site application, this waterborne intumescent coating system provides certified passive fire protection for structural steel after erection. It combines low-emission technology, long-term durability, and reliable performance.

Key Benefits

  • Waterborne, solvent-free system.
  • Fire protection classes R30–R120.
  • Tested to EN 13381-8 and classified in accordance with EN 13501-2.
  • ETA-certified and CE marked.
  • Certified service life of 25+ years.
  • Supports LEED v4 and Minergie Eco projects.
Layer Product Name Type Volume Solid Colour Shade Dry Film Thickness
Primer Teknocryl Aqua Combi 2780 Air-drying waterborne and single coat paint based on acrylate dispersion and alkyd; contains active anticorrosive pigments 42 ±2% Red Oxide, Grey 60µm NDFT
Intumescent Paint Hensotherm 421KS Waterborne, 1-component fire protection coating 72 ±3% White Depends on the steel section, fire rating requirement, and the tested performance data of this specific PFP product.
Top Coat Biora 20 Water-borne acrylate dispersion paint 37% as per specification (RAL, BS, etc.) 60µm NDFT

Contact our technical service experts and tell us about your specific project to get advice on the optimal coating system.

Download the full system with technical documentation

Designed for shop application, this intumescent coating system offers fast processing, certified fire protection, and exceptional long-term durability. It is ideal for structural steel coated in a controlled factory environment before transport to site.

Key Benefits

  • Fast overcoating intervals for efficient fabrication.
  • Fire protection classes R30–R120.
  • Tested to EN 13381-8 and classified in accordance with EN 13501-2.
  • ETA-certified, CE marked and approved to BS 476.
  • Certified service life of 50+ years.
  • Corrosion protection up to ISO 12944 C5 Very High.
Layer Product Name Type Volume Solid Colour Shade Dry Film Thickness
Primer Teknomastic 80 Primer Two-component solvent-borne epoxy primer, very low solvent. 82 ±2% Red Oxide, Grey 80µm NDFT
Intumescent Paint Hensotherm 920 KS Two-component solvent-free fire protection coating. 100% Tele Grey Depends on the steel section, fire rating requirement, and the tested performance data of this specific PFP product.
Top Coat Teknodur 0050 Two-component solvent-borne semi-gloss polyurethane top coat. 56 ±2% as per specification (RAL, BS, etc.) 60µm NDFT

Contact our technical service experts for advice on the optimal coating system for your project.

Download the full system with technical documentation

The Role of Primers and Topcoats in Intumescent Systems

In an intumescent paint system for steel, the primer and topcoat play a critical role in ensuring overall performance, durability and fire protection reliability.

The primer provides essential adhesion to the steel substrate and protects against corrosion, which is particularly important in environments with humidity or aggressive conditions.

The intumescent layer is then applied to deliver the required fire resistance.

Finally, the topcoat protects the system from environmental exposure such as moisture, UV radiation and mechanical wear, while also providing the desired aesthetic finish.

Only when all three components — primer, intumescent coating and topcoat — are correctly specified and tested together can the system achieve its certified fire performance. This is why Teknos offers fully compatible coating systems, ensuring that each layer works together as a complete and reliable fire protection solution.

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Fire Testing, Standards and Certification

Understanding fire protection standards is critical when selecting the right intumescent paint for steel.

EN 13381 – Fire resistance testing

EN 13381 defines how fire protection systems for structural steel are tested under realistic fire conditions.

EN 13501-02 – Fire classification

This standard classifies systems into fire resistance classes such as:

  • R15
  • R30
  • R60
  • R90
  • R120
  • R180

Additional standards (project dependent)

Depending on your project, systems may also align with:

  • BS 476, Certifire CF5994
  • aBG Z-1951-2629
  • Project-specific approvals

Our systems are developed on the basis of proven performance, featuring fire protection tested in accordance with EN 13381 and classified under EN 13501.

Contact our technical team for project-specific support

What determines the required fire protection performance?

The required fire protection performance of an intumescent coating system is influenced by several engineering parameters. Selecting the right system requires more than simply choosing a fire rating.

Design parameter Why it matters
Fire Resistance Class (R15 to R180) Defines how long the steel structure must maintain its load-bearing capacity during a fire.
Section Factor (Hp/A) Indicates how quickly a steel section absorbs heat. Higher Hp/A values generally require increased levels of fire protection.
Critical Steel Temperature The temperature at which the steel member can no longer safely sustain its design load.
Steel Profile Geometry Open sections, hollow sections, beams and columns can require different tested solutions.
Fire Exposure Three-sided and four-sided fire exposure conditions influence system design requirements.
Environment & Durability Class Interior and exterior conditions may require different system approvals and topcoat solutions.

Why Choose Teknos Intumescent Paint Systems For Steel?

Proven fire protection performance

  • Tested according to EN 13381.
  • Classified in accordance with EN 13501-2.
  • Designed to provide reliable fire resistance (e.g. R15 to R180).

High-quality coating system solutions

  • All in one: corrosion protection, fire protection and aesthetic appearance.
  • Optimised interaction between primer, intumescent layer and topcoat.
  • Multiple systems available: Waterborne, solvent-borne and solvent-free

Designed for both shop and site application

  • Shop-applied intumescent paint (off-site application under controlled conditions).
  • Site-applied intumescent paint systems (on-site flexibility).
  • Choose the most efficient approach depending on your project.

Compatible with different steel types

  • Carbon steel.
  • Intumescent paint for galvanised steel.
  • Complex fabricated structures.

Durable and aesthetic finishes

  • High-quality finish options from industrial grade to architectural standard.
  • Wide range of topcoat options.
  • Long-term durability in demanding environments.

Technical expertise

  • Project-specific coating system recommendations.
  • Technical specification support for architects, engineers and contractors.
  • On-site / Off-site application and system guidance, supported by technical field service.

Get Expert Advice for Your Project

Looking for the right intumescent paint for steel? Tell us about your project, and we will help you find the optimal coating system tailored to your requirements.

Contact us