Many commercial and public buildings worldwide contain structural steelwork. The steel columns themselves are not flammable. However, when exposed to a temperature of 500 °C or more, steel frames soften rapidly, and buildings can collapse. That is why fire safety is so crucial in steel-frame structures. An efficient solution is to boost the resistance of steel columns by painting them with intumescent coatings which swell in the event of a fire and protect the steel griders from collapsing. The additional minutes of stability can thus provide the adequate time needed for evacuation.
A Few Millimeters for Longer Fire Safety
The coating is usually applied one to four millimeters thick and, when subjected to heat, foams to tens of hundreds of times its original thickness, thus protecting the steel girders against heat from the fire for a longer period of time. VINNAPAS® binders enable the foaming and expansion needed, as well as long-term foam stability. At the same time, the adhesion and strength of the intumescent coatings improve, so that the protective layer firmly adheres to the substrate and forms a heat barrier for a certain amount of time. Without the binder, the foam layer would be too brittle and thus lead to insufficient adhesion to the steel substrate.
High Safety and Low Environmental Impact
Reducing VOC levels in intumescent coatings continue to grow in importance each year. Thus, a growing trend moving away from solvent-based formulations toward water-based formulations has emerged over the last few years. VINNAPAS® EZ 3067 supports this trend since it can be used in formulations without coalescing solvents. Moreover, in combination with low residual VAM monomer levels, it gives formulators the option of a very low-VOC intumescent coating (VOC < 1 g/l). Also, no raw materials containing APEOs are used in its production.
Efficient Fire Protection for Large Buildings
Fire protection in general is one of the main specialty uses for VINNAPAS® VAE dispersions. First, binders based on a combination of vinyl acetate-ethylene (VAE) and vinyl chloride (VC) exhibit flame-retardent properties which are especially appealing for ETICS/EIFS applications. Second, VAE-based binders can be used in intumescent coatings. In the construction of large buildings – skyscrapers, airports or sports stadiums – the main structure consists of steel beams. This steel structure must be protected because fire can quickly raise the temperature of the steel to 500 °C. This leads to a loss of strength in the structure – and that must be avoided.