Coating systems for structural fire protection

Steel itself is non-flammable and does not emit harmful gases in the event of fire. It therefore does not contribute to the fire load of a building, but can lose its load capacity and thus its static stability after only a few minutes under the effects of great heat. If the time to reach the critical temperature of the component does not correspond to the fire resistance duration required by building regulations, protective measures are required.

The functional principle of the fire protection coatings is based on a specific, very complex chemical product composition. Due to the thermal energy of the fire, the originally millimetre-thin coating develops into a centimetre-thick, microporous insulating foam layer that insulates the substrate against heat. Modern architecture means elegance, transparency and lightness. Sika® Unitherm® and Sika® Pyroplast® fire protection coatings combine maximum protection with aesthetic advantages. They underline design-oriented shapes and contribute to accentuation and interior design with their thin layers, excellent surfaces and a wide range of shades. A perfect synthesis of quality, safety and aesthetics.

Choosing the right coating system

Fire protection regulations

The relevant fire protection regulations require that every structural element of a building must be effectively protected from losing its load capacity and stability at an early stage in the event of fire exposure. The aim of a fire protection system is therefore to delay the temperature of 500°C (may vary depending on the country), which is critical under full load, for as long as possible in order to gain time and thus ensure the timely evacuation of the building. The function, profile, thickness and material of the steel component are decisive for the coating system and execution of the fire protection coating.

Function of fire protection coatings

Although steel structures do not burn, they can lose their load-bearing capacity and thus their static stability after only a few minutes under the effects of great heat. The functional principle of fire protection coatings is based on a specific, very complex chemical product composition.

Due to the thermal energy of the fire, the binder begins to soften on the surface and is then blown into a foam by gases emanating from a propellant it contains. Thus, the originally millimetre-thin coating develops into a centimetre-thick, microporous insulating foam layer that insulates the substrate against heat.

Coated test specimen before the fire (left image) and after the fire (right image)

The coatings, which are only about 1 mm thick, wrap themselves like a skin around the steel. In this way they ideally emphasise the construction, even with difficult detailed solutions. And they can be impressively accentuated by the colour scheme with Sika® top coats. Highly effective protection for delaying the reaching of critical temperatures.

Diagramm Einheitstemperaturkurve Brandschutz

Sika® Unitherm® and Sika® Pyroplast® are highly effective against fires and heat. The architectural beauty of steel structures is emphasised. Without thermal, chemical or mechanical influence, there is no change in composition of the completely dry coating. The performance of the fire protection is thus preserved for an unlimited period of time.

The construction determines the coating

If a steel column is located in front of the masonry and can thus be fully exposed to the thermal effect of the fire, a thicker fire protection coating is required than with columns that are partly located within the masonry. Since these are not exposed to such a great deal of heat, a thinner coating is sufficient here to achieve the required protective effect.

Combination of protection and aesthetics

Round or rectangular hollow sections are normally selected for reasons of aesthetics. Sika® fire protection coatings allow the unrestricted protection of such components without impairing their visual appearance. In addition, a broad range of colours is available that can be used purposefully as a supplementary design element.

Sika® fire protection coatings are simple to apply using airless spraying equipment or by conventional spraying or application with a brush or roller. Our products are also suitable for application in the workshop.

Connecting elements can be directly coated with Sika® Unitherm® and Sika® Pyroplast® and are thus completely protected against the effects of heat. The fire protection coating can be used in conjunction with steel structures with the most diverse sections without impairing the fire protection effect. The thinner the steel profile, the faster the heating. Thinner sections therefore require a thicker coating in order to retain their load-bearing capacity over the desired period.

System categories

NEW: 2-pack ultra-fast drying fire protection coating with single-leg spray solution

FIRETEX® FX6010 takes passive fire protection to a whole new level. This new 2-pack ultra-fast drying and durable intumescent coating delivers all the features our customers have come to expect from our passive fire protection range, but with one important new feature. Greater versatility in application, as it can be applied by a standard single-leg spray equipment.

To enable use of a more standard application method, FX6010 also offers extended pot life and working time, offering greater flexibility in use, while still maintaining durability and quick curing qualities in as little as three hours.

Which means that if you need a multi-layer intumescent coating with the convenience of application from standard single leg spray equipment, FX6010 is the solution

Designed for high value investments such as apartments, hospitals, offices, sports stadiums and transport hubs

2-pack epoxy fire protection systems – the Platinum technology

The Sika® Unitherm® Platinum technology has revolutionized the fire protection market.

The 2-component epoxy systems are weather-resistant and have an exceptionally high mechanical load capacity and chemical resistance, which promises great advantages and cost-effectiveness, both for the construction process and for the steel construction company.

While conventional products have to be applied directly on the building site due to their vulnerability and their drying takes valuable time, the quick-drying fire protection coatings can be applied directly in the factory under controlled climatic conditions.

The solvent-free epoxy resin fire protection coatings are used on steel components in indoor and outdoor areas where a top coat is not necessary. The steel fire protection systems can be applied with and without a primer, because the coatings can be applied directly to the component and can be precisely matched to the different requirements by adjusting the layer thickness and construction. A layer thickness of up to 4 mm is possible per work step. The wet film thickness corresponds to the dry layer thickness.

2 in 1: fire protection & corrosion protection

Sika® Unitherm® Platinum offers fire protection and corrosion protection in one and has been tested and certified in accordance with EN ISO 12944-6 to corrosivity category C5.

Solvent-based fire protection systems - Steel S systems

Solvent-based coating systems from Sika Deutschland GmbH are used for steel components in the interior* and exterior of buildings that are exposed to the effects of the weather, industrial atmospheres and high humidity (including the maritime environment).

They emphasise design-oriented shapes and contribute with their low coating thicknesses to the decorative accentuation and room design. These proven systems thus emphasise both the aesthetics and the protective function, without visually and spatially limiting structural design. Proven all-round systems with a durability of over 30 years have been developed in the long Sika tradition.

The application, which can also be done in the factory, is user-friendly – through the use of uncomplicated equipment.


*Use for steel components in the interior of buildings, as long as no proof of use for publicly accessible rooms is required by the national building regulations (e.g. AgBB).

Water-based fire protection systems - Steel W systems

The water-based coating systems from Sika Deutschland GmbH are free from halogens and aromatic solvents and are easy to use and not statically loading, besides which they are extremely well suited to heavily structured components too. Moreover, they emphasise design-oriented shapes, contribute with their low coating thicknesses to the architectural design and are thus qualified for decorative and sustainable building methods.

With a new bonding agent technology, our latest generation makes up the fire resistance classes from 30 to 120 minutes. Fewer work steps with high coating thicknesses but nevertheless beautiful surface quality characterise this new line of development. A VOC of 0 g/l means only the minutest of emissions, whereby the aspect of sustainability is particularly highlighted. Fast drying behaviour in conjunction with the aforementioned features makes this system enormously efficient and economical.

The products from the Steel W product range are designed for indoor use, especially for delicate structures such as hollow sections, steel gussets or truss beams.


Industrial and administrative buildings

Event and sports centres, department stores

Korrosionsschutz, Stahlhochbau, Industrial Coatings

Airports and railway stations

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