Corrosion under insulation, or underfilm corrosion, is one of the most dangerous threats to pipelines due to the complexity of detection and the speed of development. With proper selection and application of the film, the insulation protects the metal from corrosion. However, for any damage to the insulation - even to an inconspicuous eye - or if the coating is of poor quality, an air lens appears under the thin film of insulation. The lens is filled with air and water vapor, then bacteria. The interaction of the metal with oxygen and the waste products of bacteria leads to the expansion and deepening of the center of corrosion. The situation is complicated by the complexity of the visual detection of the corrosion center under the insulation. Protective zinc metallization of insulated surfaces prior to insulation is the most effective measure to prevent corrosion under insulation. Zinc prevents both the development of the corrosion process and the proliferation of bacteria. We apply composite coatings "Spramet" to prevent corrosion under insulation, heat insulation.