5 minute read
INNOVATIONS: PRESENT&FUTURE
Edited by Sika Deutschland GmbH
Stuttgart – Germany info@de.sika.com
The fire protection coating for concrete surfaces Sika Unitherm Concrete W has recently been launched on the market. Initial application examples confirm the construction industry’s need for such a product for fast and cost-effective retrofitting of fire protection in both renovation and change of use of existing buildings.
The new, 1-pack fire protection coating Sika Unitherm Concrete W forms a heat-insulating intumescent layer when exposed to heat. This prevents concrete spalling during a fire and additionally delays the heat input into the steel reinforcement.
Efficiently providing existing buildings with state-of-the-art fire protection
Sika Unitherm Concrete W can be applied directly to the cleaned concrete surface without adhesion agents or grids. The new development is compatible with repair mortar products from Sika and is therefore particularly advantageous when renovating or changing the use of concrete buildings: the applicable fire protection requirements can be brought up to date quickly, cost-effectively and in a space-saving manner - existing walls, ceilings or beams do not have to be replaced with new ones at great expense. The compatibility of the fire protection coating Sika Unitherm Concrete W with Sika repair mortars has been tested and proven in the event of fire. Sika is the only manufacturer on the market that can provide this performance feature. The fire protection coating can be applied easily and directly to the concrete by hand or by airless spraying. Thanks to a new method developed by Sika, the dry film thickness can be determined nondestructively on the concrete surface. Adhesion and functionality of the fire protection coating are not affected by this method. If required, the water-based top coat Sika Unitherm Top W is suitable for decorative, colourful interior design.
Detail of the Woolworth Haus in Mühlheim an der Ruhr (Germany).
© Sika Deutschland GmbH
In the existing building “The O” in Mühlheim an der Ruhr, the concrete ceiling had to be retrofitted for fire protection without burdening the statics. A fire protection coating with Sika Unitherm Concrete W provided the solution.
As a water-based intumescent, Sika Unitherm Concrete W is ecologically harmless. The content of volatile organic compounds (VOC) is less than one percent. This makes the product suitable for use indoors.
Renovation of a landmarked department store
The building known as “Woolworth Haus” in the centre of Mühlheim an der Ruhr in Germany dates back to the 1920s. As a high-quality, artistically outstanding building, it represents the architecture of the time and is therefore a listed building. In the course of a change of ownership, the concrete building was converted and renovated. This also required a fire protection retrofit of the former department store.This was because the concrete ceiling was too thin and therefore insufficient to adequately protect the reinforcing steel in accordance with the required fire protection class R60. Due to the building’s statics, however, it was not possible to clad the ceilings with heavy fire protection walls or to apply an additional five-centimetre-thick concrete layer. The new fire protection coating for concrete, Sika Unitherm Concrete W, therefore came into question as an optimal, weight-reduced alternative. After sample surfaces had been laid with Sika Unitherm Concrete W, the product received positive evaluations from all project participants and was therefore used in the existing building. To achieve the required fire resistance R60, the applicators applied
a uniform film thickness of 1.5 to 2.0 millimetres in two work steps, depending on the respective existing surface structure. The processing company confirmed the particularly easy application of Sika Unitherm Concrete W: after training the employees, they were able to apply the product professionally right away. After application, the fire protection coating must dry out for eight hours before its dry film thickness can be determined. Sika’s special method is used for this purpose, since the dry film thickness on concrete substrates cannot be determined with conventional measuring equipment. The handy drums in which Sika supplies the fire protection coating also proved to be advantageous for smooth logistics on the construction site.
© Sika Deutschland GmbH
Individual design of the fire-protection coated surfaces
The building, which now bears the name “The O” in memory of the first building owner Hugo von Othegraven, will in future house an apartment and a penthouse apartment in addition to gastronomy and commercial space. In some of the new retail spaces of “The O”, the concrete ceiling was to remain visible, creating a modern and elegant industrial look. This requirement was optimally implemented with the top coat Sika Unitherm Top W in the colour black.
Renovation of an underground car park
In addition to several public buildings in Austria, the underground parking garage of the Unterland School Centre in Eschen, Principality
© Sika Deutschland GmbH
The fire protection coating for concrete Sika Unitherm Concrete W can be applied quickly and easily by airless spraying. A wet film thickness gauge is used to check the thickness of the fire protection coating. To achieve a fire resistance of R60, the coating must be up to 2 millimetres thick.
© Sika Schweiz AG
of Liechtenstein, has now also been fire-protection retrofitted with Sika Unitherm Concrete W. The concrete ceiling of the parking area was coated with Sika Unitherm Concrete W in a film thickness of 0.5 millimetres. As a result, the prescribed fire resistance R60 can now be achieved despite the lack of reinforcement cover. Verification of the correct coating thickness using the Sika method was carried out at control points on ten concrete columns in the underground garage. Sika Unitherm Top W in the colour RAL 9016 was applied as the top coat. Sika products were selected because of their simple and time-saving application. Another decisive factor was that the parking area could be designed according to the aesthetic requirements of the client.
Sika Unitherm Concrete W fulfils numerous European and national standards
The fire protection coating Sika Unitherm Concrete W has successfully passed numerous tests: the fire resistance of the fire protection coating system was tested for concrete structures “walls and ceilings” in accordance with EN 13381-3:2015 for concrete strengths C 30/37 and C 50/60. It may also be used for columns and beams of strengths C 30/37, C 50/60 and C 90/105 according to EN 13381-3:2015. At C 90/105, the protective coating prevents concrete spalling for up to 120 minutes. Furthermore, environmental product declarations and sustainability data sheets are available for Sika Unitherm Concrete W. ‹
© Sika Schweiz AG
The underground car park of the Unterland school centre in the Principality of Liechtenstein has recently been renovated with Sika Unitherm Concrete W for fire protection.
The concrete ceiling of the parking area under the Unterland School Center in Eschen has been coated with Sika Unitherm Concrete W in a film thickness of 0.5 millimeters. This means that the prescribed fire resistance R60 has now been achieved.
