Thermal Spray Removal of Lead-Containing Paint of Steel Structures

In the past, red lead primer has been used on many steel structures to control corrosion. Commonly used structures in the Department of Defense DoD include bridges, aircraft hangars, water storage tanks, metal buildings, fire hydrants, and structural steel. When the lead-based paint cannot be overcoated because of peeling, it must be removed before repainting. The use of conventional abrasive blasting for removal requires a tight containment structure to keep the lead dust from contaminating air, soil, and water. Increased worker protection is required inside these containment structures because of high dust concentrations. The personal protective equipment PPE is time-consuming to put on and cumbersome to use, which reduces worker productivity and drives up costs. This Environmental Security Technology Certification Program ESTCP project demonstrated the Thermal Spray Vitrification TSV process, in which molten glass is sprayed on the coated structure. The glass encapsulates the lead-containing paint and falls off on cooling because of the thermal stresses. The collected waste is vitrified so that it can be disposed of as non-hazardous waste or recycled into value-added products. The demonstrations and validations of the TSV process were conducted on a bridge at the Rock Island Arsenal, Illinois in 1997 and on an aircraft hangar door at the Marine Corps Base at Kaneohe Bay, Hawaii in 1998. These demonstrations met all of the performance objectives, which were to 1 remove lead-containing paint from steel structures in the field, 2 meet all applicable environmental standards, 3 meet all applicable worker health and occupational safety standards, 4 enable recoating of the substrate using a surface-tolerant coating system, and 5 collect data and estimate production rates.