Polyurethane foam is a material obtained by mixing two components, polyol and isocyanate. The chemical reaction that takes place results in a solid, highly resistant and stable foam that can be manufactured in two ways. Thus, by projection, the two components are sprayed simultaneously onto the surface to be insulated (the substrate). On the other hand, by injection, the mixture is prepared and introduced into a cavity, where it expands to achieve the insulating effect.
In either form, and also as a sheet and as a sandwich panel, polyurethane is a material widely used in renovations and new construction. In addition, it plays a leading role in sustainable construction, given its high performance as a thermo-acoustic insulator. In this way, the different polyurethane systems are an essential tool for achieving energy efficiency. However, false myths circulate about a material that is so versatile, resistant and profitable that it is worth banishing.
Is the polyurethane foam fire resistant?
The various polyurethane insulation products have good fire performance. In fact, they comply with European standards, obtaining in the classification of Euroclasses - included in the UNE-EN 13501 standard - a rating of between F and Cs3d0 for bare foam and up to B-s1,d0, in a construction solution.
In addition, there are polyurethane insulation products on the market with fire resistance, specifically polyurethane sandwich panels with EI15, EI30 and EI60.
As far as toxicity is concerned, the fumes generated by the combustion of polyurethane are similar to those generated by other organic products present in buildings, such as wood, cotton or cork. Furthermore, in the tests carried out, the polyurethane products located in different construction elements have behaved similarly to other materials with a higher classification in Euroclasses.
The fire protection of polyurethane insulation systems
The polyurethane insulation products found in building structures are usually protected with materials that have a higher fire resistance. This is the case with concrete, brick, plaster, mortar or sheet metal. In this way, once a fire has occurred, enough time must pass for the flame to overcome these protective elements and reach the insulation.
Moreover, polyurethane foam does not melt or drip when it burns, as is the case with plastics; on the contrary, it carbonises, so the core is protected for a while, thus maintaining a certain stability. This is why polyurethane systems will never cause a fire. This type of accident is usually caused by human action or irresponsible waste management.