HVAC Failures of Copper Exchange Units

Copper alloys in the work hardened condition have been know, to fail in service by environmentally assisted Stress Corrosion Cracking (SCC).

The authors have over twenty years participated in the diagnosis, investigation of causation and thresholds that ammonia, and amide substances cause these

often termed static fatigue. In this investigation Copper and Copper alloys in the annealed condition have been evaluated. Organic chemical and traditional

industrial exposures and consumer service environmental failures will be reviewed and the results presented.

The conclusions are that relatively small concentrations of Manufacturing (AIDS) substances and not Domestic (Ammoniated) cleaning solutions caused

these unusual failures. Literature references confirms a Formicary type of progressive damage and ultimate failure,