Protective Coating System Design for Insulated or Fireproofed Structures

Corrosion of carbon steel equipment beneath thermal insulation and concrete is a critical concern among refineries, chemical plants, marketing organizations, and pipelines. Corrosion has been detected worldwide under all types of thermal insulating materials. At Exxon this concern has been addressed in a number of laboratory investigations and also during field troubleshooting assignments. This paper describes work undertaken to develop protective coating systems suitable for equipment to be insulated or fireproofed. These systems are described. In addition, the advantages of organic coatings compared to inorganic zinc-rich coatings are reviewed. Also discussed are recently completed novel evaluations to select coating systems for thermally insulated and thermally cycled equipment.