Bridge Expansion Joint for Bridges in Corrosive Industrial Atmospheres

Bridge expansion joints near chemical plants, refineries, and other industrial facilities face unique challenges from corrosive atmospheric pollutants. The joint design must provide enhanced corrosion protection to achieve the required service life in these aggressive environments. Corrosive pollutant identification is the first step in designing joints for industrial environments. The types and concentrations of corrosive pollutants must be identified from the industrial facility's emission data. Common corrosive pollutants include sulfur dioxide (SO2), hydrogen sulfide (H2S), chlorine (Cl2), and hydrogen chloride (HCl). Corrosivity assessment for industrial environments uses the ISO 9223 framework to determine the corrosivity category. Industrial environments with high concentrations of corrosive pollutants may have a corrosivity category of C5 (very high) or CX (extreme). The corrosivity category determines the minimum coating system required. Coating system selection for industrial environments requires careful consideration of the specific corrosive pollutants present. Standard epoxy coatings may not be adequate for environments with high concentrations of acids or solvents. Chemical-resistant coatings based on fluoropolymers or phenolic resins may be required for the most aggressive industrial environments. Rubber seal selection for industrial environments must consider the chemical resistance of the seal material to the specific pollutants present. EPDM rubber has good resistance to many industrial pollutants but limited resistance to petroleum products and solvents. Fluoroelastomer (FKM) seals have excellent chemical resistance but are more expensive than EPDM. Maintenance frequency in industrial environments must be increased to account for the accelerated deterioration. Quarterly inspection may be required for joints in the most aggressive industrial environments. Any damage must be repaired promptly to prevent escalation.