For decades, the evaporative cooling industry has relied on galvanized steel as a preferred material of construction due to its cost effectiveness and thermal performance.  

Galvanized zinc provides corrosion protection for the underlying carbon steel. This zinc layer is both a protective layer and acts as a sacrificial anode when any damage or breaks occur. When properly passivated, new galvanized steel can provide significant corrosion resistance to extend the service life of the steel. 

Given sufficient contact time in the atmosphere, the outer layer of newly galvanized steel will naturally passivate. This passive layer protects the zinc from a form of premature corrosion known as White Rust.  

Many projects lack the time to allow this passivation process to occur naturally in the atmosphere before needing to start their evaporative cooling equipment under heat load. The need to operate the equipment wet increases the potential for White Rust formation. A field passivation is often required to create the surface reactions required to form a passive oxide layer on a new galvanized coil. Properly passivating new galvanized coils is more difficult when immediate heat load is required since elevated temperatures increase corrosion potential. Once white rust forms, it cannot be eliminated, which can create both short and long-term problems. 

To improve real world passivation plans for evaporative cooling equipment commissioned with immediate heat load, EVAPCO® engineered an enhanced 2-step passivation solution to minimize white rust for galvanized equipment, Pass Protect ®. 

To learn more about our Pass Protect ® offering and how to best commission your galvanized coil, please contact your local EVAPCO® sales representative or [email protected] .