Intrinsic Antimicrobial Properties of Copper in HVAC Applications
Ever wondered why those sparkling copper pots and pans are every popular? Aside from steadily, effectively, and equally conducting heat, the surfaces of these copper pans are found to have antimicrobial properties.
The surfaces of alloy and copper materials, as discussed in the original article, have inherent properties that are able to hinder the growth of pathogenic and microscopic microorganisms. When studied and analyzed under metallurgical microscopes, these surfaces are proven to have antimicrobial properties that starts being effective in hours.
Aside from cooking utensils, copper and alloy materials are extensively used as building materials. In this generation, people are more aware of the potential health risks of materials used in buildings. People are concerned with being contaminated or exposed to pathogenic organisms (biologic or chemical). Heating, ventilation, and air-conditioning (HVAC) systems are more susceptible to microscopic growths (fungi, bacteria, etc). There is a need to improve the hygienic conditions of HVACs as well as a need for better materials that could reduce the presence of these pathogenic microorganisms and also reduce cases of sick building situations.
The dark and damp components of HVACs make them an optimum environment for mold, bacteria, and spore growth. The most common pathogens found in HVACs, as cited in the original article, are Legionella, sp, and molds, such as Aspergillus niger. Dr. C. W. Keevil, as narrated in the original article, compared the growth of Aspergillus niger in aluminum and copper coupon materials. He found out that the spores became nonviable in the copper coupons while the spores in the aluminum coupon was still viable or alive. He made another material test using broth, the spores, and the aluminum and copper coupons. The results after 10 days of incubation revealed that the spores did not germinate on the broth placed on copper coupons while in the aluminum coupons, spores were germination on the broth.
Comparing pure copper, brass copper, and stainless steel, Keevil also tested the possible growth of a superbug called Methicillin-resistant Staphylococcus aureus (MRSA) in these materials. Results revealed, when these specimens were examined under metallurgical microscopes, that pure copper materials can eliminate more of these superbugs compared to brass copper while stainless steel did not reduce the viability of Methicillin-resistant Staphylococcus aureus (MRSA).
Studies were also conducted in determining if the pathogenic microorganism Legionella pneumophilia can be reproduced and germinated on plastic, metal, and copper materials. The results of the studies show that Legionella pneumophilia can be germinated on the biofilms of plastic surfaces even with temperatures of up to 50°C. Legionella pneumophilia cannot germinate on copper, however. The original article also shows a table depicting the hierarchy of biofouling activity. The hierarchy revealed that copper is the best material while plastic surfaces and some metal surfaces are in the bottom of the hierarchy. How can this be applied in real situations? These results will provide reasonable proof that stainless steel or plastic evaporator drains are not advisable. Since copper and alloy have been proven to have antimicrobial properties as seen on metallurgical microscopes, these materials are now commonly used by engineers and contractors. Read on this subject
