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  • 1.  EPA Officially Says Copper Surfaces Help Fight COVID-19

    Posted 03-30-2021 13:43
    Edited by Joanne Miller 03-30-2021 13:54

    On February 10, 2021, the Environmental Protection Agency (EPA) announced that it has registered certain copper alloys that have demonstrated effectiveness against viruses, including SARS-CoV-2. In this digital-first article from Advanced Materials & Processes, ASM International's flagship magazine, Harold Michels, who authored the initial article in this materials science and coronavirus series, returns to provide context to the EPA announcement.

    Read the full digital-first article, which will also be published in the April 2021 issue of Advanced Materials & Processes (AM&P) magazine.



    This article is the eighth installment in an AM&P series on materials science and the coronavirus.

    READ THE DIGIT FIRST ARTICLE HERE

    @Harold Michels is an independent consultant with expertise in physical metallurgy and corrosion of copper alloys, nickel alloys, stainless steels, as well as other alloys systems. He has a special focus on the antimicrobial properties of copper alloys. Prior to his executive role at the Copper Development Association, he held a variety of positions with Inco Limited, including concurrently serving as director of strategic planning, and president of the La Que Center for Corrosion Technology. He has a Ph.D. in materials science from New York University. He is a lifetime member of ASM International and member of the ASM Long Island Chapter.
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    Joanne Miller
    ASM International
    Materials Park OH
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  • 2.  RE: EPA Officially Says Copper Surfaces Help Fight COVID-19

    Posted 03-31-2021 15:06
    I browsed through the article and while it says that alloys with as little as 60% Cu were tested, the EPA certificate linked (EPA Reg. No. 82012-1) only refers to alloys with >96.2% Cu.  So I pulled up the online Desk Edition, 2nd Ed., and it shows that alloys meeting this should be Coppers, C10100-10576, and High-copper alloys, C16200-C19600 for wrought, and Coppers C80100-C81100, and High-copper alloys C81300-C82800 for castings.  (The latter group is technically ">94% Cu", so all might not qualify under that particular EPA certificate.)

    While this is all good, these grades have generally lower machinability and strength.  (And look out for the 'dangerous' ones like the beryllium-containing grades!)  Until and unless the higher-alloyed brasses and bronzes are found to be certifiably viruscidal manufacturers won't sell them as such. 

    As others have discussed maybe retrofitting surfaces is a possibility.  There may grow a cottage industry of travelling electroplaters who will go through your building, transit station, planes and trains, etc. applying the certified alloys to existing stainless and plated surfaces that are already present, improving the public health prospects.  A solvent wipe, quick power abrasion, and a plating pen / brush later, presto! a safer surface.

    An aesthetic concern will rear its head however.  Remember the Sacagawea golden colored dollar coin, which turned brown?  Coppers in contact with the skin tarnish, and the nice shiny stainless surfaces (previously teeming with germs and viruses) being altered will not look good after a short period, and the soft deposits will quickly be worn by constant use. 

    And materials engineers will have to fight off the marketers who will want any parts kept nice and coppery in appearance by coating them with lacquers, which of course will destroy any viruscidal properties of the surface.  So overall, I am dubious that this whole path will lead to a large-scale alteration in materials for touch surfaces, unless it's legislated.

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    Paul Tibbals
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  • 3.  RE: EPA Officially Says Copper Surfaces Help Fight COVID-19

    Posted 04-01-2021 00:25
    Paul, 
    You have really done a great analysis.Just want to add that Copper is not suitable for cooking due to its reaction with acidic foods, resulting in toxicity. In lndia we would regularly get copper and brass vessels tinned many years back. But now stainless steel is being used for most of the job.
    While Aluminium is falling out, Cast iron vessels are finding greater acceptance.
    Many opportunities for materials professionals coming up.

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    Rahul Gupta
    Managing Director
    N D Gupta Enterprises
    Pune
    +919423009829
    RahulRahulRahul
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  • 4.  RE: EPA Officially Says Copper Surfaces Help Fight COVID-19

    Posted 04-01-2021 03:16
    Paul,

    Agree with most of what you have said. The plating stuff wont work and is neither practical. However the most vulnerable areas should be protected. All fittings in hospitals, care centres, Airports and bathrooms of hotels, clubs, airports and even homes need to be retrofitted with Copper Alloy fittings. There are alloys with Copper higher than 96% available ( and I am not considering Copper Beryllium - which is dangerous anyway) that can do the job. Copper Titanium is one such alloy - which has the strength and mechanical properties equivalent to CuBe but is completely Beryllium free. Its easily machinable and can be produced in many shapes and form. Ofcourse it will get tarnished like other copper alloys, but that will give it an antique look, and can be cleaned easily with a wipe like on stainless steel. The tarnished look is a small visual distraction to live with to save humans from the deadly viruses and bacteria of all kinds. Copper Titanium and similar alloys are far more expensive than stainless steel, and that maybe a real battle with sales people and users. But that will be a one time cost with long term recurring benefit on a daily basis for thousands of people who touch such parts.

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    Lalit Kumar Pahwa
    Managing Director
    Pahwa MetalTech Pvt Ltd
    Pune
    +91 98500 20000
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  • 5.  RE: EPA Officially Says Copper Surfaces Help Fight COVID-19

    Posted 04-01-2021 04:35
    A splendid recollection, Paul!

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    Donato FIRRAO FASM
    Professor
    Politecnico di Torino
    Torino
    +393351494032
    Italy
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  • 6.  RE: EPA Officially Says Copper Surfaces Help Fight COVID-19

    Posted 04-01-2021 12:47

    Dear Paul:

    You are correct, but this registration is a pioneering event in this era of COVID-19.  The initial submission to the EPA, that resulted in the registration alloys only covered alloys with >96.2%Cu.  I am no longer involved in the EPA submission process since I am retired.  I do recall that the EPA generally limits the composition ranges and number of alloys that can be submitted at one time.  However, subsequent submissions will no doubt work their way down to alloys of lower copper content. This pattern was followed in the initial registration of antimicrobial copper against specific infection-causing bacteria, in which I was heavily involved. 

    In response to aesthetic concerns, tarnish-resistant alloys C706 (90%Cu-10%Ni) were widely used in clinical trials and demonstration projects.  However, the EPA advised that although registered copper alloys are antimicrobial, they should still be regularly cleaned and disinfected, just like any other surface.  Although basses (zinc-containing copper alloys) are prone to tarnishing, they are deployed since routine cleaning will remove the tarnish. Even if an alloy develops tarnish, it is found to be antimicrobial, based upon lab cursory tests.

    Only alloys listed in the Unified Numbering System (UNS), which is  the accepted alloy designation system in North America for wrought and cast copper and copper alloy products,have been registered by the EPA.  Plated surfaces are not part of the UNS system and to my knowledge have not been registered by the EPA.  If they are claiming antimicrobial efficacy and do not hold an EPA Registration, they may be subjected to EPA action. 

    The Sacagawea golden colored dollar coin contains 77%Cu-12%Zn, 7%Mn and 4%Ni.  It is a coinage alloy and not a general engineering alloy. Since coinage alloys are not part of the UNS system, it was not registered.

    Thank for your for thoughtful comments,

    @Harold Michels, PhD, ASM Life Member

    ​

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    Harold Michels
    Consultant, Formerly Senior Vice President, Copper Development Association
    Retires from Copper Dev Assoc in 2014 & Inco Ltd. in 1998
    Manhasset NY
    (516) 627-5335
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  • 7.  RE: EPA Officially Says Copper Surfaces Help Fight COVID-19

    Posted 04-01-2021 03:27
    Edited by Dmitriy Dzhurinskiy 04-01-2021 08:59

    It is quite confusing to me. Yes, it is known for years that Silver and Copper have an antibacterial effect. However, both materials DO NOT work as an antimicrobial surface when DRY [1, 2]. Moisture needs to be present at the material's surface and so Copper would have an antibacterial effect, like Silver does. In addition, 
    the temperature plays a critical role as well. Surface temperature at around 36 C is ideal (most in-vitro tests are done at this level of temperature). However, the antimicrobial effect vanish while the temperature drops

    [1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2779462/
    [2]     https://theconversation.com/copper-is-great-at-killing-superbugs-so-why-dont-hospitals-use-it-73103



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    Dmitriy Dzhurinskiy
    Assistant Professor


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  • 8.  RE: EPA Officially Says Copper Surfaces Help Fight COVID-19

    Posted 04-01-2021 08:23
    Edited by Melodie Bonin 04-01-2021 08:24

    Professor Dzhurinskiy, 

    I think I either misunderstand your comment or you might have misread the articles as both states that copper is effective as an antibacterial surface, better than silver because it does not need specific humidity or temperature conditions. 



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    Mélodie Bonin

    PhD student
    Université Laval
    Québec QC
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  • 9.  RE: EPA Officially Says Copper Surfaces Help Fight COVID-19

    Posted 04-03-2021 01:05

    Professor Dzhurinskiy:

    Of course efficacy of any antimicrobial solid-state agent will be sensitive to the conditions at the surface-level in terms of environmental influence, but the assertion that moisture is a prerequisite to mediate copper-based contact killing or viral inactivation goes against careful studies and findings concerned with that very matter.

    Silver and Cu are also not equivalent in their antimicrobial, oligodynamic action-abilities either (and, in fact, nor is CuO equal to Cu2O in kill rate and neither is Cu2+ ions of equal lethality relative to Cu1+ ions).

    For a direct demonstration of dry contact killing occurring in a matter of minutes, in comparison with buffered, moist or wet surface contact killing, which occurred within hours, see: https://aem.asm.org/content/77/3/794

    In any case, I'd suggest the following works and their referenced materials too:

    1. https://jbioleng.biomedcentral.com/articles/10.1186/s13036-021-00256-7
    2. https://www-asminternational-org.ezpxy-web-p-u01.wpi.edu/search/-/journal_content/56/10192/42945592/NEWS
    3. https://www.mdpi.com/2073-4352/10/6/504
    4. https://doi.org/10.1557/adv.2020.366
    [Opens in a new window]
    Hope this helps shed some additional light on the interesting aspects surrounding antimicrobial copper from a materials-mediated and processing condition approach too.

    Best,
    Bryer C. Sousa, WPI



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    Bryer Sousa
    PhD Candidate
    Worcester Polytechnic Institute
    Worcester MA
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