Copper Aids Fungal Emission Control in HVAC Systems

A presentation at the US Environmental Protection Agency's recent Committee on Indoor Air Quality concluded that copper can be helpful in controlling the emission of fungi from heating ventilation and air-conditioning systems.
26th February 2013
In densely-occupied buildings, airborne microbial contaminants can result in numerous adverse effects on human health by causing infections, allergic responses or toxic effects. Consequently, microbial growth in HVAC systems and subsequent contamination of the indoor air environment is of increasing concern. Copper - with its inherent ability to rapidly and completely eliminate bacteria, viruses and fungi on contact - is of great interest to researchers in the HVAC field.
Dr Michael Schmidt, Professor and Vice Chairman of Microbiology and Immunology at the Medical University of South Carolina, offered data from comparisons of HVAC systems using copper versus systems using aluminium during use in buildings. The work was conducted in Fort Jackson, the US Army's largest basic training base, and was supported by the US Army Medical Research and Materiel Command.
In the field study, all heat exchangers and drip pans were replaced in each of two near-identical Army barracks. In one barracks, the replacements were fabricated with aluminium, and in the other they were fabricated with copper. Each barracks had three floors, with two heat exchangers on each.
After a sixteen-week schedule of sampling (covering both heating and cooling seasons), the researchers found concentrations of airborne fungi were significantly lower in the copper barracks than the aluminium barracks, and there was no evidence of biofilm formation on the copper heat exchanger.
Dr Schmidt's presentation concluded that copper can be helpful in controlling the emission of fungi from HVAC systems. He recommends additional research to explore the impact of copper HVAC systems in occupied spaces, and also copper's effect on typical bacterial levels.
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