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Architectural Design with COVID in Mind: Which surfaces best resist viruses?

By Sam Giglio

It’s already halfway through the summer of 2020, but it definitely doesn’t feel like it. One quick look around in any semi-public place will tell you that people are taking many personal precautions as recommended by the CDC to limit transmission of COVID-19, mainly wearing facemasks and maintain social distance of greater than six feet. These measures are great at preventing the primary way coronavirus is thought to spread: from person to person.[1] This, in and of itself, has some interesting implications for architectural design, the most common being creative ways of denoting six foot distances in queues and tight spaces.

Figure 1: Zocalo Food Truck Park in Milwaukee’s Walker’s Point Neighborhood employs creative sidewalk art to denote appropriate distances and flows for waiting queues. Photo Credit: Sam Giglio

However, this isn’t the only way that the Coronavirus can spread. Depending on the material, COVID-19 can survive for days on surfaces and objects like counters, handles, doors, and buttons. While cleaning surfaces more frequently is one solution to this problem, designing with COVID in mind is yet another. We’re Architects: it’s in our nature to think about design interventions that can augment the ways we live, and in this case, survive and thrive.

So, what are some of these design strategies that can be used to limit spread of coronavirus on objects and surfaces? Let’s take a look at the most promising three!

Method 1: Inherently Antiviral Materials

Figure 2: An example of a brass faucet and lever detail in a bathroom as an example of a high-touch copper design intervention. Photo Credit: Micheile Henderson

Something even many designers don’t know are the inherently antiviral effects of copper and copper alloys, but the idea isn’t a new one. In fact, ancient cultures from Greece and Egypt to China and the Americas used copper to treat wounds, store food, and treat water via ionization.[2] Today, it is used in the manufacture of a variety of medical and lab equipment and the EPA has even approved of its use.

So how does this work? A study published by the American Society for Microbiology explains that it comes down to a cellular process of contact killing. This means that, on contact, the copper itself starts to break down the genetic material of microbes. The process isn’t fully understood, but copper is thought to break down the cell membrane and deconstruct the genetic proteins, leaving microbes unable to reproduce. Put simply, copper objects and surfaces can self-disinfect without frequent cleaning due to their chemical makeup.

Method 2: Antiviral Material Textures

Figure 3: A laser cutting table can etch specific micro-textures into a variety of materials. Photo Credit: Michael Jarmoluk

Not everything can be made of copper, so what other solutions do we have at our disposal? Adding micro-textures to a variety of materials has yielded some interesting results. Researchers at Purdue University have focused on increasing surface area and making the surfaces hydrophilic, causing an increase in the rate of contact killing of the virus present in water droplets.[3]

Another unlikely source is providing a couple additional avenues: the cicada’s wings. Biochemists at Swinburne University of Technology in Victoria, Australia describes how the wings are both hydrophobic and micro-abrasive[4]. Hydrophobic materials operate opposite to the Purdue strategy: droplets carrying viruses will simply run off the surfaces, leaving the surface sterile. Additionally, structures called nanopillars have been shown to stretch and tear microbial membranes, at least in bacteria, though viruses are much smaller and would require texturing of far greater precision.

So, universities and research institutes across the globe are exploring possibilities in this arena, but custom products would most likely need to be coordinated with specific manufacturers at this point because a lot of the research, though promising, is still in early stages. The good news is, methods such as laser etching and 3D printing that are used in these methods are familiar to design professionals and manufacturers, so collaboration on this front is certainly possible.

Method 3: Antiviral Surface Coatings

Figure 4: Extracts from hops as an antiviral coating? It’s being explored at the Institute for Engineering of Polymer Materials and Dyes in Poland. [5] Photo Credit: Rita E

 The last option with perhaps the least limiting impacts on material choice are antiviral coatings. Unfortunately, the accessibility of these methods comes with a drawback: research results are mixed as to the various product’s efficacy and certified post-market commercial products are hard to find as a result. Extracts from tea tree, cork, or even hops have had limited success in studies[6], but it is unclear how these materials could be used to target specific viral strains.

On a similar note, contractors and manufacturers are aware of a variety of hydrophobic coatings for surface materials such as wax, polyurethane, and oil-based finishes. However, since these don’t operate the same way on a microscopic level, it’s not certain that these finishes will provide any of the same benefits that hydrophobic micro-textures.

Conclusion

In conclusion, some design interventions are currently available, primarily copper and copper alloys. Others such as micro-texturing and antiviral coating are still in experimental stages. It will be exciting to see where these products go and if these design strategies are accelerated as a means to prepare for any future outbreaks.

Cost is obviously a primary consideration in the choice of materials as well. In addition to the cost of copper or brass hardware, Allume interiors specialist Natalie Tetzlaff says that it’s important to look at the impact of these design decisions on the rest of the space. Flooring, casework, and paint to match rustic or warmer-colored hardware will result in a space that feels different from one that uses nickel hardware and complementary neutrals and accent colors.

And if you’re curious how copper stacks up against other materials, we’ve compiled a handy chart based on information from the New England Journal of Medicine on the persistence of COVID-19 on different types of surface materials[7]:

[1] Center for Disease Control – Coronavirus Disease 2019: Frequently asked questions: https://www.cdc.gov/coronavirus/2019-ncov/faq.html#spreads

[2] CrestOptics – Antimicrobial Copper: a miracle in healthcare? https://crestopt.com/antimicrobial-copper-a-miracle-metal-in-healthcare/#:~:text=Copper%20and%20copper%2Dcontaining%20alloys,within%20two%20hours%20of%20contact.

[3] Purdue Engineering – Treating Metal Surfaces to Kill Bacteria: https://www.youtube.com/watch?v=3vFFdNXsoN0&feature=youtu.be

[4] Springer Nature – Insect wings shred bacteria to pieces: https://www.nature.com/news/insect-wings-shred-bacteria-to-pieces-1.12533

[5] Institute for Engineering of Polymer Materials and Dyes  - Studies of biocidal properties of a hop extract in antimicrobial coatings: https://www.researchgate.net/publication/291802835_Studies_on_use_of_hop_extract_as_a_natural_biocide_in_coatings

[6] BBC Future – The surfaces that kill bacteria and viruses: https://www.bbc.com/future/article/20200529-the-surfaces-that-kill-bacteria-and-viruses

[7] The New England Journal of Medicine – Aerosol and Surface Stability of SARS-CoV-2 as Compared with SARA-CoV-1: https://www.nejm.org/doi/full/10.1056/nejmc2004973

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