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Should I use disinfectants or UV-C to fight COVID-19?

Posted by Francine Pitassi on

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Cleaning and disinfecting are more important during the coronavirus pandemic than ever before.

But which method should you use: cleaning products or ultraviolet disinfectant lighting like UV-C products?

The short answer: both.

Right now, your primary goal is most likely to get rid of SARS-CoV-2, the virus that causes COVID-19. Both cleaning products (specifically disinfectants) and UV-C light can inactivate the virus. But they work in different ways to protect employees, customers, and tenants in your facility.

A thorough cleaning process requires three steps:

  1. Cleaning: Wiping down surfaces to remove dirt and grime
  2. Disinfecting: Removing germs and pathogens
  3. Protecting: Continuously removing pathogens from surfaces

It's important to make sure surfaces are clean before you use any kind of disinfectant. Then after a disinfectant is applied, using a protectant can work continuously to reduce the number of pathogens on a surface.

When should you use disinfectants and when should you use UV-C products? Let's compare the two in three ways:

How disinfectant products work compared to UV-C light

The goal of disinfectant products and UV-C (also called germicidal UV) products is the same: to disinfect surfaces and stop the spread of germs.

How they achieve that goal is different.

How disinfectants work

Disinfectants destroy or damage the cells of pathogens like bacteria and viruses. This is done after a surface is cleaned.

Disinfectants are different than your standard water and soap. In order to be considered a disinfectant, the product should technically be registered with the Environmental Protection Agency (EPA).

The EPA has a list of registered products that target SARS-CoV-2, the virus that causes COVID-19.

These products typically require a set amount of time to be effective against certain viruses or bacteria.

Lysol, for example, recommends wetting a surface for 30 seconds then allowing it to air dry. To get rid of pathogens that are harder to kill, the surfaces should remain wet for even longer, sometimes up to 10 minutes.

If a disinfectant requires 10 minutes to work properly, it's important to make sure the surface stays wet for the full 10 minutes before it dries.

Once the surface is dry, a protectant can be applied.

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How UV-C products work

Germicidal UV products destroy the DNA and RNA in the cells of pathogens so they can't replicate.

Here is a more scientific explanation from the Illuminating Engineering Society (IES), a trusted resource in the lighting industry:

"Individual, energetic UV-C photons photochemically interact with the RNA and DNA molecules in a virus or bacterium to render these microbes non-infectious. This all happens on the microscopic level."

how-uv-works

Similar to disinfectants, it's important to use UV-C after a surface is clean. The rays emitted from products cannot penetrate dust and dirt particles.

People frequently ask us if UV-C products are effective against SARS-CoV-2. Preliminary results from a Columbia University scientist show that UV-C can inactivate the virus that causes COVID-19.

This finding is not surprising to many scientists since UV-C light has been proven to inactivate other types of coronaviruses.

The effectiveness of disinfectants vs. UV-C light

At first glance, it seems simple. Both disinfectant products and UV-C products claim they are 99.9% (or higher) effective against pathogens like viruses and bacteria.

But are they really? And what can interfere with those results?

Effectiveness of disinfectants

Most disinfectants are 99.999% effective against germs, but the biggest obstacle is human error. Cleaning crews can limit the effectiveness of the products.

First, a thorough initial cleaning is important.

Second, the surface may not be wet long enough to kill pathogens. Products should list a recommended amount of time for the disinfectant to be on the surface in order to kill germs.

Third, cleaning crews may simply miss or forget surfaces as they are working through a room.

Regardless of the reason behind the error, studies in hospitals have shown that disinfectants were less than 50% effective on high-touch surfaces. In some cases, that leads to incidences of hospital acquired infections (HAIs).

Even when disinfectants are used properly, they are only effective until germs re-enter a space, which could be minutes or hours. That's why protectants are so important. 

Effectiveness of UV-C products

The effectiveness of UV-C products is often talked about in log kill rates. A log kill rate is the percentage of viruses and bacteria inactivated by UV light.

According to the IES, a 2-log kill rate is commonly accepted. That equals a 99% inactivation of pathogens. A 3 or 4-log kill rate is even better.

Log reduction Percent reduction Remaining parts
1 90% 100,000
2 99% 10,000
3 99.9% 1,000
4 99.99% 100
5 99.999% 10
6 99.9999% 1


But similar to cleaning products, the actual efficacy will likely be different in laboratory settings than in the real world.

One of the biggest obstacles for UV-C products is the line of sight rule. The "light" or UV rays emitted from a product is impacted by shadows and objects in a room. To achieve full disinfection, you may have to run multiple cycles with the right dose.

Additionally, UV products cannot penetrate dust or other particles on a surface.

Even with those obstacles, hospitals have found using UV-C can reduce HAIs. But the most effective approach is using both disinfectant products and UV-C light.

If this "one-two punch" can work for hospitals, it will likely be even more effective in other commercial buildings like restaurants, retail stores, offices, and schools.

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Side effects of disinfectants vs. UV-C light

Disinfectant products and UV-C products both have side effects that can be harmful for humans.

The standard operating procedure for both should be to follow manufacturer guidelines and existing safety protocols.

Side effects of disinfectants

Disinfectants are chemical agents by nature. If handled improperly, they can harm the skin, lungs, and even surfaces.

The smell from disinfectant cleaning products can be dangerous for cleaning crews and anyone entering the room after it's cleaned, especially those with asthma.

To reduce side effects, it's important to follow these safety guidelines from the EPA.

Regency is sourcing low-toxicity disinfectants that are still registered with the EPA, but non-corrosive and safe enough for kids toys and food surfaces.

puregreen24 vital-oxide
PureGreen24
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Vital Oxide
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Side effects of UV-C products

Exposure to UV-C light, specifically products in the 254 nm wavelength, can cause burns to the skin and eyes.

Manufacturers recommend running UV products in empty rooms only. Anyone who needs to perform maintenance or operate products should wear appropriate protective equipment, like gloves, goggles, and long sleeves.

It's also important to make sure germicidal UV products are properly installed to limit side effects.

How to disinfect your building

Disinfecting your building requires a multi-layered approach:

Pairing all of these approaches will result in the highest level of disinfection, protecting your customers, employees, and tenants.

Our lighting specialists are ready to help find the right solution for your facility.

Here are other resources you may find helpful:

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