Ecogreen Clean Teknologi

The real effect of UV disinfection on the escalator handrail surface

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Since the outbreak of coronavirus infection (COVID-19), which threatens the health and safety of many, governments, individuals and markets around the world are all focusing more on the keywords “sterilization”, “disinfection” and “prevention”.

To prevent the spread of the coronavirus, governments and health organizations are recommending and implementing surface disinfection of public facilities, along with personal masks, frequent hand washing, and cough etiquette.

During this period, UV sterilizers, which are said to have a disinfecting function, are being released and sold.

In fact, UV sterilizers existed around us like the tableware (cup) sterilizers and toothbrush sterilizers found in food courts and at home.

These products kill germs by irradiating ultraviolet rays in an enclosed space while holding objects to be disinfected such as toothbrushes and cups.

However, recently, even products that claim to be able to sterilize the surface of moving objects that are not stationary with ultraviolet rays are on sale.

Even the escalator handrail, which is an open public facility that we frequently use, and even keeps moving, is said to be sterilized with ultraviolet light.

Typical UV sterilizers that irradiate UV rays on the surface of a fixed object continuously for 10 to 60 minutes make sense,

But can moving objects other than a fixed cup or toothbrush be sterilized with UV rays in a moment? 

Ultraviolet sterilization is usually used in the form of a mercury lamp or LED that irradiates UV-C in the wavelength range of 250 to 280 nm (nanometer), which has a sterilizing effect.

In addition to the Republic of Korea, mercury lamps and all mercury-based products have been prohibited from mining, importing, exporting, and manufacturing under the “Minamata Convention” from 2020.

In addition to the above, most of the sterilizers use UV-C LEDs because of the short life of the mercury lamp.

Ultraviolet sterilization using UV-C LED is the principle that when ultraviolet rays of UV-C wavelength are sufficiently irradiated to germs such as viruses or bacteria, DNA in cells is destroyed and no longer grows and dies.

This requires “sufficient energy” and “time” to break the double strands of DNA, depending on the type of germs.

According to the principle of ultraviolet sterilization, this sterilization method requires a lot of conditions, such as sufficient energy and time to destroy DNA, and close distance.

In a word, this is called UV irradiance (energy) or UV Dose.

UV irradiation energy can be calculated from the LED’s electrical output capacity, distance to the target, and exposure time to UV light.

* UV dose = ( LED output ÷ squared distance ) x exposure time

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As above, the LED output is high, the distance is short, and the exposure time is long to generate “sufficient energy” for sterilization(disinfection).

With the following three pages document, you can check whether UV-C LED irradiation is truly sterilizing for moving object surfaces.

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ecogreen article
ecogreen article

This document is intended for the handrail surface of an escalator, which is a publicly used facility, and the conclusion is that UV sterilization on the surface of moving objects is not effective.

As a basis, it used the moving speed of the escalator, the LED output capacity, and the UV light energy (UV dose) required for sterilization of each bacteria.

The escalator in Korea moves 50cm per second, which is said to be very slow compared to the world average.

Even on a handrail moving at this speed, the UV irradiation time is only 0.16 seconds, so “sufficient energy” for UV sterilization cannot be generated.

In order to sterilize 99.99% of Pseudomonas aeruginosa, the cause of sepsis, which we have encountered in our daily life or through articles, it is said that in order to sterilize Pseudomonas aeruginosa, it must be stopped for 22.67 seconds and continuously irradiated.

Korea’s Centers for Disease Control and Prevention, World Health Organization (WHO), CDC (American Centers for Disease Control and Prevention), and other governments, health organizations, and media recommend that unverified UV sterilization be regulated and not used.

Only disinfectants and cleaning methods with proven disinfecting effectiveness are officially recommended.

Along with the announcement of the test results of the Korea Consumer Agency on December 23, 2020, media outlets also reported that some of the UV sterilizers on the market have no sterilization effect or that the amount of UV emission is at a dangerous level, but there is no protective equipment.

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ecogreen article

Publicly used facilities such as escalators in subway or shopping mall, which many people use frequently, must be disinfected.

WeClean, developed by SWIT Inc., a company specializing in facility sanitization systems, is a product that “actually” disinfects and cleans escalator handrails using an eco-friendly disinfectant.

WeClean is already installed in subways, airports, terminals, hospitals, department stores, and shopping malls in over 60 countries, as well as in Korea including Seoul Metro Lines 2-8.

In order to prove that it is actually sterilized, we have conducted on-site sterilization tests of escalators several times by domestic and foreign accredited organizations, and have been certified for 99.99% killing germs effect.

With a real sterilization effect of 99.99%, WeClean sterilizes the moving escalator handrail surface in a secondary sterilization.

First, it disinfects 99.99% by simultaneously cleaning and disinfecting via FDA-registered disinfectant and 3-tier cleaning roller.

As recommended by the WHO and CDC, cleaning the surface of the facility and disinfecting it with disinfectants, like WeClean, should be performed simultaneously and frequently to prevent the spread of viruses.

Finally, UV-C LED is irradiated over the entire surface of the handrail to which the disinfectant is applied.

The UV-C rays used here react with the hydrogen peroxide component of the disinfectant rather than for direct disinfection, and are used to immediately disinfect residual germs via the Advanced Oxidation Process (AOP).

AOP is a rapid oxidation and sterilization method through a large amount of hydroxyl (OH) radicals generated when UV-C rays are irradiated to hydrogen peroxide.

It is a very fast and powerful 21st century eco-friendly sterilization technology used in large wastewater treatment facilities.

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ecogreen article

WeClean is the world’s first and only product to actually real disinfect and clean the surface of escalator handrails.

WeClean will take care of yourself so that you do not hold the handrail or worry about it because of the contagion caused by contact with the handle when boarding the escalator.

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Disinfectors to prevent the spread of viruses or infectious diseases are directly related to your health and safety.

We ask you to purchase or use after checking whether sterilizers with such an important purpose can actually disinfect.

Thank you.

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