How Corrosion Can Reduce the Life Expectancy of School HVAC Systems

Corrosion causes $276 billion in damage every year and an estimated $1 trillion in indirect costs. Metal pipes, joints, tubes, vents, and towers lose structural integrity and fail simply from being exposed to water and air.

Scientists are searching for ways to combat the problem. A New York University developed a technique to make metal super-hydrophobic by etching nanoscopic patterns onto its surface. Materials scientists in Illinois are using 40 million processor hours on a supercomputer to study corrosion at the atomic level.

Outside the lab, however, the battle against corrosion continues.

The Impact of Corrosion on HVAC Systems in School Buildings

Corrosion is a chemical reaction that affects the physical and mechanical properties of the metal. When the integrity of a metal component is compromised, its strength is reduced and its useful life is diminished. Corrosion can be a serious problem in the large HVAC systems used in school buildings because metal components in heat exchangers, pipes, coils, cooling towers, chillers, and vent stacks can rust, leak, or fail if corrosion goes unnoticed.  Over time, corrosion can increase operating and maintenance costs, damage equipment, and demand early replacement of expensive parts.

Outside the building, coils and other metal parts are subject to corrosion from the elements, such as ocean water in coastal areas, pollution in industrial towns, and agricultural chemicals in rural areas. Inside the building, high relative humidity and leaks can damage the remaining HVAC machinery.

Rust, water stains, pitted metal, and greening copper is signs of corrosion. When pipes are insulated or hidden behind walls, corrosion can go unnoticed for months or even years. Common areas for corrosion are the bypass lines, low flow sections, threaded joints, and dead ends.

Preventing Corrosion in HVAC Systems

Taking an HVAC system off-line without a plan is never a good idea. Leaving water in boilers or coolants in tubes can cause severe damage as the system sits idle for months. Proper layup techniques can protect the life of heating and cooling systems and reduce downtown when it comes back online.

A boiler can have a wet layup or a dry layup, depending on the needs of the school. Both versions should include a series of steps to empty, flush, clean, dry, and repair the system. Air conditioning components go through a similar checklist when taken off-line. The system should be drained, cleaned, inspected, and dried. For both systems, general maintenance during layup should include cleaning coils, clearing drains, lubricating mechanical parts, and replacing gaskets.

Many HVAC operators apply a special coating to HVAC components during layup to prevent corrosion. For the best protection, this coating must be applied in optimal conditions following the manufacturer’s specifications. Manufacturers often recommend running dry air through the system to ensure the coating on internal components dries properly.

Desiccant dehumidifiers are an effective way to control moisture as these coatings are applied and dried. Polygon offers temporary climate and humidity control solutions that create the ideal environment for surface preparations and coating. The custom-built technologies accommodate areas of any size so the space has the perfect temperature and relative humidity levels, regardless of the weather outside. Call today to learn more about how Polygon assists with corrosion prevention.

[Photo from Randall Chancellor via CC License 2.0]