The city of Lakeland, Florida, needed to re-coat one of its three steam-generating systems, McIntosh Power Plant, Unit #1. The system had been constructed in 1969 and then recoated in 1977, on both occasions, a lead-based primer had been used. To comply with Environmental Protection Agency standards, city officials ran TCLP tests for 13 heavy metals. The finding showed that the plant’s coating exceeded EPA standards for lead. As a result, Lakeland was required to contain all particulate removed from the facility.
Lead abatement is the process of removing lead paint hazards; if done incorrectly, it can result in a variety of problems, the most serious of which are safety concerns. Lakeland encountered many challenges in its process to recoat its systems, including hazardous materials escaping, completion deadlines, temperatures, and humidity management.
Lakeland needed to contain all lead particulate during the blasting project, thus a massive temporary containment structure was constructed. The 100-foot-square-by-150-foot-high building created a vast area of 1.5 million cubic feet that was needed to enclose Unit #1. Inside, 565,000 cubic feet of air had to be changed twice each hour.
To execute the project effectively, Tom Cochran, project manager for the City of Lakeland, had to manage four complex factors at the same time. He asked Polygon to assist him in conceiving and then building a cutting-edge environmental control system designed to facilitate lead abatement, temperature and humidity control, visibility, and a strict completion date.
Polygon created a system that controlled humidity and temperature consistently, maintaining inside air conditions at 80°F and relative humidity of less than 60%. The system completely changed the air twice each hour, removing all particulate. It maintained negative air pressure while off-setting positive pressure was created by 10 blasting hoses.
Because of other maintenance programs, the project had to conclude by December. This was hurricane season, which typically had high humidity, rain, and storms. As a result, it is the most difficult period to conduct blasting and coating projects.
“Meeting our deadline was a concern,” said Cochran, “as it is crucial that shutdowns be conducted when our demand for power is the lowest. With two maintenance projects scheduled back-to-back, we could not afford delays on Unit #1.”
All exposed surfaces had to be blasted clean of the deteriorating lead-based coatings and re-coated. “Since we had decided to remove the coating,” said Cochran, “we also had to meet EPA standards, which required that no particulate reaches the outside air. This was a matter of great concern to us since it involved the health of our employees.”
As a first step toward meeting these requirements, a contractor was hired to build a massive temporary containment structure over Unit #1. It was made of tubular scaffolding and lightweight plastic panels. All joints were taped to prevent the outside air from leaking in.
To ensure that no particulate escaped, the air was filtered while holding humidity and temperature. Two 20-ton DX units with a 40-ton chiller were combined to create the capacity to hold the blast and maintain a reasonable working temperature while processing the 565,000-cu. ft. of the air twice each hour. Eliminating particulates, required two dust extractors with capacities of 27,000 scfm and 20,000 scfm were used. Once the dust was extracted, extremely fine particulate was removed with a HEPA filter.
Another concern was visibility during blasting, according to Polygon’s Ken Gernenz: “For safety, Lakeland wanted the blasters to see 10 feet. Our system created 60 feet of visibility.”
Unit #1 was coated with a surface-tolerant epoxy primer and a surface coat of hi-bild aliphatic polyurethane. By holding conditions, Polygon allowed the coating process to proceed around the clock. “It was a pleasure to work with Polygon,” said Cochran. “It was not a simple project, but working together we created a unique solution.”
Substantial Cost Reductions
By avoiding work interruptions, Lakeland avoided the high cost of delays—delays that are common when humidity is out of control during blasting and coating projects.
Ensured Coating Performance
Using humidity control, Unit #1 could be blasted entirely without corrosion occurring. The primer adhered firmly, and curing was improved by controlled temperature and humidity conditions.
No Problems with Regulations
OSHA and EPA standards were met with our climate control system. Project workers and city employees were protected from harmful lead particulate and working conditions were optimized.