Fire protection

Each intumescent paint has appropriate documents, including the European Technical Assessment or ITB Technical Approval. This is a document containing all information about primers and topcoats that can be used with a given intumescent paint. These coatings are checked in tests and approved by the manufacturer of the fire-retardant paint for the painting set. Typically, specific product names and types are provided (e.g. anti-corrosion epoxy primer) or it is written according to which standard a given paint must be produced in order to be a primer for intumescent paint. For example, the following primer paints can be used up to the C3 corrosion class for the Flame Stal fire-retardant paint: - solvent-based epoxy anti-corrosion primer - alkyd primer paints meeting the requirements of PN-C-81901:2002 (this information should be included in the product's technical data sheet) In the case of paint Fire retardant Steelguard 651 we no longer have so much freedom and a primer should be used from the specific products listed in the European Technical Assessment. Another example is Nullifire SC803 paint, where we can choose from: - two-component solvent-based epoxy primers - solvent-based alkyd primers - water-based acrylic primers To sum up, fire retardant paint cannot be applied over any primer paint. If there is already some paint on the structure and we do not know exactly what kind of coating it is, unfortunately it should be removed. The use of primer paint that does not comply with the documentation may result in acceptance problems or the entire painting system becoming detached during a fire.

There is no clear answer to this question. The thickness of the coating, and therefore the amount of layer, of fire retardant paint depends on three factors. The first one is the indicator of the massiveness of the steel profile cross-section. This indicator is different for different steel profiles, for example for the IPE240 I-section it is 236 [1/m] and for the UPN300 U-section it is 162 [1/m] (in the case of profiles exposed to fire on four sides). The second factor is the critical temperature, which should be determined by the designer. The critical temperature may be, for example, 550ºC, but may also be 650ºC. For each of these values, the coating thickness for the same steel profile will be different. The third factor is the required fire resistance class. The classes are marked R15, R30, R60, R120. The number indicates the time in minutes - how long the fire-retardant coating delays the structure reaching a critical temperature during a fire. In other words, it can extend the time to evacuate people or conduct firefighting operations. The higher the fire resistance class, the greater the thickness of the intumescent paint coating. For example, for the previously mentioned IPE240 I-beam, the critical temperature is 550ºC, assuming that it is a column: - for class R15 - 0.226 mm dry with Nullifire SC803 paints - for class R60 - 0.684 mm dry with Nullifire SC803 paints

We select fireproof paint depending on the profiles that make up the steel structure and the required class of fire protection. We always choose the paint optimally for a specific case, so as to obtain the thinnest possible coatings and, consequently, a lower price of the material per square meter. Some paints work better on open profiles (e.g. I-beams), while they are unfavorable for closed profiles (e.g. square pipes).

There is no general recommended film thickness for fire retardant paint. The thickness of the fireproof paint is selected based on the required protection class (R15, R30, R60...), the critical temperature and the massiveness index of the steel profile cross-section. On this basis, the thickness of the intumescent paint coating is selected from the tables in the European Technical Assessment issued for a given product.

The recommended method of applying fire retardant paint is airless spraying. It is not always possible to use spraying, sometimes we also have to paint several beam feet protruding from the ceiling and in such a case spraying will not be economical. In such cases, we can apply swelling paints by hand, but they are quite thick and when painted by hand (roller, brush) the structure will remain (orange peel after the roller, gray after the brush). You should also remember that when applying with a brush in one layer, we will not apply a coating thicker than 150-250 microns dry. For higher protection classes, the required dry coating thickness may be up to 1,500 or 4,000 microns. It is easy to calculate that this means the need to apply, for example, 10 layers with a brush, while spraying can apply up to 800 microns at one time.