Demonstration of Corrosion-Resistant Coatings for Air-Conditioning Coils and Fins

Department of Defense military installations operate air-conditioning equipment in humid and coastal locations that produce high levels of corrosion. Installation experience has shown that severe corrosion has reduced expected equipment life cycles by up to 50. This project for the Office of the Secretary of Defense Corrosion Prevention and Control Program demonstrated and evaluated the performance characteristics of two corrosion prevention coatings on condenser coils in highly corrosive environ-ments. This work assessed the capabilities and advantages of an aluminum-impregnated polyurethane coating and a flexible epoxy polymer applied to two separate condenser units at Schofield Barracks, Hawaii. The work also included fabricating and exposing test coupons of various substrates, each coated with the two coating systems and a third coating commonly used in less-corrosive environments. These coupons were exposed both at the Schofield Barracks site and in a laboratory-accelerated expo-sure cabinet. The work recommends that copper rather than aluminum components be specified in air conditioners operating in highly corrosive environments. A copper substrate protected with a newer type of corrosion coating is projected to extend the equipments expected life cycle from 710 years to 2530 years. The return on investment for the project is 3.89.