By the term intumescent coating, we mean a coating with a thickness varying from some a hundred microns to a few millimeters, applied according to the classic and usual paint echniques (brush, roller, spray). An intumescent coating must have the characteristic of swelling, below the action of heat, its original thickness, forming an insulating foam whose job is to prevent the transfer of heat from the source to the support on which it is applied. The purpose of the coating is therefore that of keeping the support, for some time, at temperatures such that the deformation process or collapse (iron structures) is slowed down and hindered, thus actively contributing to the stability of the structure in case of fire. This also simplifies the design of the load-bearing metal structures since, with protection light, uniformly distributed, profiles and shapes of any kind become feasible; contrarily to what happened in the past, when the protection consisted of complex conglomerates, coatings orcement-based infills. Under the effect of heat, the original layer of the film swells into a foam whose thickness is proportionalthe quantity of material applied; the insulating power of the foam, its stability and durability, they depend exclusively on the materials chosen for the formulation of the paint.