Case Study: Cooling Tower Repair

ZRC is the Coolest!

High atop the Southern Natural Gas Company (SoNat) headquarters building-- the tallest building in Birmingham, Alabama -- sits what appears to be a series of large galvanized steel boxes. These are the building's cooling towers. Situated atop large buildings across the southern states, the voluminous, box-like cooling towers are used to contain water that is circulated throughout the building's air conditioning system.

The warm, humid weather of the southeastern United States is a difficult environment for materials of any kind. When you add the effects of constant water submersion found in cooling towers, the results can be devastating. Assailed by the elements outside and the constant flow of water inside, cooling towers are a prime target for corrosion.

Repair or Replace?

This was the situation that faced Fifth Avenue Realtors of Birmingham, the organization responsible for maintenance of the SoNat building. Corrosion damage to the cooling towers over the years had reached a critical stage, and the building owners had to make a choice: replace the Marley cooling towers with new units, or make repairs. Given that replacement would be expensive and require the use of a specialized lifting helicopter, the decision was made to repair the cooling towers.

Through Marley representatives Palmer & Lawrence, Inc., the building owners turned to Miller Builders of Pace, Florida, specialists in the rehabilitation of cooling towers. Miller's recommendation? Regalvanizing with ZRC.

We had worked extensively with ZRC on other projects, and found it to be highly effective prevention for rust and rust creepage, even in the harshest conditions. Our contacts with Stuart Smith of Corrosion Managers, Inc. in Birmingham, the local distributor for ZRC made the project run as smoothly as anything we've ever done.

Bobby Miller | Miller Builders

ZRC On Top

The process began in July, 1995, when the cooling towers to be repaired were subjected to a high pressure (1,500-3,000 psi) water wash with sand injection. This method proved to be much faster than the tedious process of wire brush cleaning. The cooling towers were then vacuumed clean and allowed to dry.

Next, ZRC was applied by brush. Two coats were applied, to a dry film thickness of 2-3 mils. The coating was allowed to dry for a full two weeks before the cooling towers were put back in service. This drying period was critical to allow for the proper curing of ZRC, providing ample time for solvent evaporation and oxidation to occur, creating a strong electrochemical bond between the coating of ZRC and the metal surface of the cooling tower.

The towers were immediately placed back on line during the hot Alabama summer. A thorough inspection was conducted in December, revealing no degradation at all -- a remarkable accomplishment given the heavy use and challenging environment. Fifth Avenue Realtors plans to rehabilitate five additional cooling towers using ZRC during 1996.

Cool Results

The success of ZRC in extending the life of the cooling towers on Birmingham's SoNat Building is just one example of the many uses of ZRC in preserving a major capital investment by preventing rust and corrosion. For nearly half a century, ZRC has been the world's leader in zinc coatings technology. Just ask the cool and comfortable individuals working in the SoNat Building.