The coke foam formed from the intumescent paint at the beginning of the fire effect is a good heat insulator and allows to protect the building structure elements from critical heating (from 500 °C) for some time. However, violations of technology on the real object can cause coking defects. And an insufficiently accurate assessment of the quality of the intumescent coating and foam in the laboratory can endanger the fire hazard of an object at risk. There are oversimplifications, limitations, and uncertainties in the existing laboratory procedures for testing fire-retardant properties of the intumescent paints. In this regard, many problems arise. The main property of the intumescent paint is tested under the influence of fire, that is, after the formation of the coke foam. Therefore, the fire test should be carried out only after the coating is completely ready at the facility. Аlso the area of the test coating should be significantly larger (20–80 cm2) than that of laboratory samples, since the functioning of paint and foam in real conditions is somewhat different. Additional study is required of the number of properties and behavior of intumescent paints that are capable to cause hidden defects in the original coating and foam. The authors highlight two main factors that cause hidden defects: incorrect choice of the thickness of the intumescent paint layer and excessive dilution of it before applying. Currently, the regulatory documentation does not regulate such important properties of the coke foam as the density and thickness of the layer, which determine the structure fire safety. An important task of future research is to find the ways to quickly identify violations of paint manufacturing and application technology, which lead to a critical deterioration in the properties of the future coke foam. The ultimate goal of the study of the methodology of fire protection, the authors see in the development of a comprehensive technique for detecting hidden defects when testing fire-retardant properties directly at the object, at large areas of fire-retardant coating (20–80 cm2), with the subsequent restoration of this area if the intumescent paint passed the test.

adhesion of a charred layer to the surface of constructions and materials is one of the main components of fire protective efficiency of intumescent charring compositions, especially for metal surfaces. The paper overviews literature sources concerning the investigation of adhesive-cohesive properties of charred layers. It is shown that there are no easily performable methods for assessment of these properties. The laboratory device based on the «back strike» method has been developed. Adhesive-cohesive properties of charred layers modified with carbon additives were assessed using «back strike» method and pushing method. It is shown that these methods provide equal results.

Purpose. Existing methods for checking the quality of intumescent coatings do not allow determining the implicit properties of these coatings, for example, the properties of foamed coke (FC), which is formed from a layer of intumescent paint during a fire. The authors analyze the issues of developing a measuring tool kit to evaluate intumescent coatings outside the laboratory, thus minimizing the possibility of using inappropriate quality paints and excluding violations of the work technology. Methods. The work uses theoretical research and experimental methods for measuring physical and mechanical parameters. Findings. The results of studies of the FC structural and mechanical properties obtained from the most popular intumescent paints Defender M Solvent are given. A scheme for a comprehensive assessment of intumescent coating properties is developed. To assess the FC quality a set of measuring tools is proposed, including equipment of our own design. Research application field. The results obtained are the basis for the development of an express analysis methodology for intumescent coatings quality directly at the construction site to ensure fire safety of these facilities. Conclusions. The proposed measuring tool kit makes it possible to assess the quality of the foamed coke by the following parameters: layer thickness, intumescent coefficient, compressive strength, shear-detachment strength. This set of parameters is sufficient for assessing the working properties of a fire proof coating and allows revealing hidden defects of the intumescent paint directly at the place of its application.

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