Protective Coating Industrial Coating Passive Fire Protection Article

Passive fire protection is a vital component of any fire safety strategy for buildings. Built into the structure, it safeguards people’s lives and limit the financial impact of damage to buildings and their contents. Sika provides comprehensive solutions for fire resistant constructions such as tunnels, commercial and residential buildings and steel structures especially. Fire resistant coatings for load bearing structures enable to build secure buildings.

Fire Protective Coatings for Load Bearing Structures

With Sika® Unitherm® and Sika® Pyroplast® fire protective coatings, quality and cost-optimised solutions can be realised depending on the required fire-resistance class, the subsequent building codes and the local conditions. Whether steel structures, timber construction elements or concrete – our product portfolio offers reliable building protection according to national and international standards and is used in many important buildings and complexes around the world.

Through continuous, market-focused development work, the Sika fire protective products are classified and usable in accordance with the latest European requirements, directives and EN standards.

  Man Applying Fire Resistant Coating on a  load-bearing structure

Function and Chemistry of Fire Protective Coatings

Although steel constructions do not burn, very high temperatures can cause them to lose their load-bearing capacity and thus their static stability within a few minutes. The functional principle of fire protective coatings is based on a specific, very complex chemical product composition.

Due to the thermal energy of the fire, the bonding agent begins to soften at the surface and is then swelling by the gases produced by an integral foaming agent to form a foam. The originally millimetre-thin coating converts into a centimetrethick, micro-porous insulating foam that insulates the substrate against heat.


Combination of Protection and Aesthetics

Circular or rectangular hollow sections are most frequently chosen for their visual appearance.

Sika® fire protective coatings allow the unrestricted protection of such components without impairing their visual appearance. In addition, a broad range of decorative finishes will also enhance the appearance of the structure purposefully as a supplementary design element.

Graph comparing fire resistance of steel: uncoated vs. Sika Unitherm Coat
Steel Structure Outside a Building in the evening


Unlike wooden constructions, steel doesn’t burn. But effective fire protective is nonetheless critical here as well. When exposed to extreme heat levels, steel loses its load-bearing capacity and becomes unstable. This puts buildings at risk of collapsing.

Fire protective coatings from Sika extend the fire resistance rating of steel structural components to up to 150 minutes, compared with just a few minutes when left unprotected material. A coating thickness with just a few millimeter is sufficient to achieve this. The function, profile, thickness and material of the steel parts are decisive for the required structure and the application of the fire protective coating.

Wood Structure inside a building protected with fire protective coating


Wood is a natural building material with a multitude of uses. However, it is flammable and requires effective means of protection especially when used in public buildings.

Sika® Pyroplast® Wood fire protective systems can inhibit or delay inflammation on the surface and the spread of flame. The sustainable fire protective coatings combine highest protection with aesthetic advantages. Although the coating is so thin it does not conceal the natural beauty of the wood.

Fire protective flooring system of a hangar


Like steel, concrete does not burn and belongs to the Class-A building materials. However, the high input of heat resulting from the fire leads to a reduction in the strength and rigidity of the concrete. That causes explosive spalling also for high strength concrete mixtures up to the collapses of the entire construction. Fire protection for concrete is used where a fire protection retrofit is necessary in a building due to a change of use or inventory.

Markus Woehr

Markus Wöhr
Market Development Manager
Target Market Industrial Coatings
Sika Deutschland GmbH