Tagged with 'uv disinfection'

Nichia UV LED, new releases update: July 2021

Nichia UV LED, new releases update: July 2021

Nichia UV LED product line update 07-2021


Nichia is the world's largest LED manufacturer, leading the supply of innovative LEDs to all markets, including UV and UVC LEDs. Durability, brightness and homogeneity are among the major strengths of the Nichia brand. Furthermore, the fine selection allows greater added value for professional processing.

As of 07-2021 the UV portfolio of Nichia as the presented below, with new additions:

  • New UVC LED: NCSU434A at 280nm and 17.5mW for 0.5W power
  • Update of UVC LED: NCSU334B, radiant power increased from 55mW to 70mW at 280nm for 1.8W power
  • New UVA LED: NWSU333B, with an amazing radiant power of 4900mW at 365nm for 12.25W power

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Fluence (UV Dose) Required for up to 99% disinfection from Viruses, Bacteria

Fluence (UV Dose) Required for up to 99% disinfection from Viruses, Bacteria

The information below is extracted from the research paper: "Fluence (UV Dose) Required for up to 99% disinfection from Viruses, Bacteria, Protozoa and Algae"  that can be downloaded also on our website at the links below:

PDF: Fluence (UV Dose) Required to Achieve Incremental Log Inactivation of Bacteria, Protozoa, Viruses and Algae

Germicidal action of UV radiation

The effectiveness of sterilization or disinfection with UV light depends on the exposuretimewavelength and irradiance.

  • Exposure or fluence (sometimes called dose) is measured in mJ/cm2 (where 1 mJ/cm2 = 10 J/m2)
  • Exposure time is measured in seconds (s), minutes (m) or hours (h)
  • Irradiance is the flux of radiant energy per unit area, in other words how much of the UV radiation power (measured in W = 1000 “miliwatts” mW = 1.000.000,00 “microwatts” μW ) reaches the surface. Irradiance is measured in mW/cmor W/m2 (1 mW/cm2 = 10 W/m2) and is dependent on the radiant power, distance and dispersion of the radiation emitted by the lamp source.

Many studies that show the effectiveness of UV light in disinfection or sterilization present in their findings the inactivation of virus or bacteria for a given Exposure in an amount of time, for a given UV wavelength. However, it is difficult to centralize or build a database with so many variables. The most common solution to this problem is to present the fluence required to achieve a log reduction from 1 to 5.

 Log reduction explained

"Log reduction" is a mathematical term (as is "log increase") used to show the relative number of live microbes eliminated from a surface by disinfecting.  For example, a "5-log reduction" means lowering the number of microorganisms by 100,000-fold, that is, if a surface has 100,000 pathogenic microbes on it, a 5-log reduction would reduce the number of microorganisms to one, equal to 99.999% kill rate.

Log Reductions from 1 to 5 are the most common in research papers about UV light disinfection. Their meaning:
  • 1 log reduction means the number of germs is 10 times smaller (101)
  • 2 log reduction means the number of germs is 100 times smaller (102)
  • 3 log reduction means the number of germs is 1000 times smaller(103)
  • 4 log reduction means the number of germs is 10,000 times smaller(104)
  • 5 log reduction means the number of germs is 100,000 times smaller(105)

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Disinfection with UV Light, >99% Kill Rate for Viruses (incl COVID-19) or Bacteria

Disinfection with UV Light, >99% Kill Rate for Viruses (incl COVID-19) or Bacteria

Effective and cost efficient disinfection or sterilizing of surfaces, water and objects has become of huge importance. The current COVID-19 (coronavirus) pandemic made this extremely clear. It created a extreme buying spree for everything that can be used in fighting it.  Never before seen shortages of disinfectants, surgical masks, gloves, ventilators and more, happen all across the globe.

The situation is made worse by the fact that many of the materials used for sterilisation are single use and have to be disposed afterwards. More have to constantly produced, exacerbating supply issues. It is time for a more efficient way of killing virus and bacteria, it is time for disinfection with UV light.

  "UV light annihilates viruses and bacteria by destroying their ability to reproduce. " 


Using ultraviolet (UV) light to disinfect or sterilize1 has actually been embraced by some hospitals since years, by using large, industrial-grade machines to kill microorganisms (including COVID-19) in hospital rooms or on furniture, objects, clothing or instruments. However, such machines are prohibitively expensive for private or business use, as a mobile platform with UV lamps can cost more than 60.000 USD2. They are also dangerous for people and have to be used only in empty rooms.


UV robot for hospital use


With the current advance in UV LED lighting technology, smaller versions of safe to use UV disinfection lamps can now be available to consumers and companies looking to clean pretty much everything, from office spaces, elevators and living rooms, to phones, computers and even toilet seats.

Widespread use of UV light to fight virus and bacteria can now happen with the technology of continuous disinfection with low intensity UVA light from lighting emitting diodes (LEDs).

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Advice for the purchase and use of equipment for the UV disinfection of air and surfaces

Advice for the purchase and use of equipment for the UV disinfection of air and surfaces

This article is intended as a guide for those who are considering purchasing UVC disinfection equipment in 2021. These tips should only be considered as suggestions.

Attention buyers! - There are few recognized standards for equipment designed for UVC disinfection of air and/or surfaces. As a result, there are many advertisements and promotions claiming amazing performance with little or no scientific support.

  • Ask the seller for copies of scientific papers that prove that his device actually works as he claims. The scientific work(s) should show the actual reduction of a test micro-organism in the environment in which the device is intended to work. 
  • Does the product have suitable built-in UV safety sensors for automatic shutdown or does safe operation depend entirely on the operator?
  • Does the device comply with NIOSH, UL, IEEE and related safety standards in the country of sale?
  • Does the unit emit/generate ozone? If so, does it meet NIOSH requirements. How is the ozone attenuated? (We recommend avoiding ozone equipment, as it poses a safety risk to operators, unless ozone is specifically part of the treatment process and is used in a controlled and safe manner)?
  • Is the device used to disinfect medical devices? If so, is it compliant with the requirements of the regulatory body in the EU, USA or country of sale?
  • If the device is a UV rod that is used to disinfect a surface (e.g. a worktop or an envelope)

The technical specifications should state the UVC irradiance at a fixed distance from the UV front of the device (e.g. 10 mW/cm2 at 2 cm).

The UV dose (irradiance multiplied by exposure time in seconds) should be at least 20-40 mJ/cm2 to inactivate viruses on perfectly flat and ideal surfaces (details in this article). Thus, if the irradiance at the target surface is 10 mW/cm2, the exposure time should be 2-4 seconds. However, the presence of microscopic gaps on flat surfaces can inhibit disinfection, and disinfection on other materials, such as cloths, may require completely different doses. For example, disinfection of viruses on medical masks may require doses as high as 1000 mJ/cm2. This is a subject that is currently being researched and our current understanding changes almost daily.

With any UV device, you must NOT look at the UV light or expose your hands from the UV side. UV light is a source of skin burns/cancer and can quickly damage the eyes.

Remember that UV disinfection is based on a "line of sight" between the UV lamp and the target surface. If the UV rays are shaded by texture elements on the surface, the shaded areas may receive much less UV light or no light at all. Disinfection effectiveness is therefore determined by the UV dose to which these areas are exposed.

Like any disinfection system, UVC equipment must be used properly to be safe.

They all generate different amounts of UVC light in wavelengths from 200 - 280 nm. UVC light is much more energetic than normal sunlight and can cause a severe, sunburn-like reaction on your skin and could also damage the retina of your eye when exposed.
Some devices also produce ozone as part of their cycle, others produce light and heat like an arc welder, and still others move during their cycles. In general, all disinfection devices must therefore take into account the safety of both man and machine.

These considerations should be taken into account in the operating manual, in user training and in compliance with appropriate safety regulations.

Fact Sheet on UV Disinfection for COVID-19 (2021 update)

Fact Sheet on UV Disinfection for COVID-19

The scientific community now strongly believes that UV disinfection technologies can play a role in a multiple barrier approach to reducing transmission of the virus that causes COVID-19, SARS-CoV-2, based on current disinfection data and empirical evidence. UV is a well-known disinfectant for air, water and surfaces that, when used correctly, can help reduce the risk of infection from contact with the COVID-19 virus. Leading experts from around the world have gathered to develop a guide to the effective use of UV technology as a disinfection measure to reduce transmission of the COVID-19 virus.

It should be noted that "UVC", "UV disinfection" and "UV" as used here and in the scientific, medical and technical literature refer specifically and importantly to UVC light energy (200-280nm light) in the germicidal range, which is not the same as UVA and UVB radiation used in tanning beds or sun exposure.

Facts about UV and COVID-19

Can UVC help prevent the transmission of COVID-19 by reducing contamination?

Based on the available evidence, scientists believe so. Here's why:

  • UVC light has been used extensively for more than 40 years to disinfect drinking water, wastewater, air, pharmaceutical products and surfaces against a whole range of human pathogens. All bacteria and viruses tested to date (many hundreds over the years, including other coronaviruses) respond to UV disinfection. Some organisms are more sensitive to UVC disinfection than others, but all tested to date respond at the appropriate doses. For info about the Fluence (UV Dose) Required for up to 99% disinfection from Viruses, Bacteria, Protozoa and Algae , based on 413 reasearch papers, read our related article.
  • UVC disinfection is often used in conjunction with other technologies in a multi-barrier approach to ensure that any pathogen that is not 'killed' by one method (e.g. filtering or cleaning) is inactivated by another (UVC). In this way, UVC could now be installed in clinical or other settings to supplement existing processes or shore up existing protocols when they are exhausted by excessive demands due to the pandemic.
  • COVID-19 infections can be caused by contact with contaminated surfaces and subsequent touching of facial areas (less common than human-to-human, but still a problem)[vi]. Minimising this risk is critical as the COVID-19 virus can survive on plastic and steel surfaces for up to 3 days[vii]. Normal cleaning and disinfection may leave some residual contamination that can be treated with UVC, so a multiple disinfectant approach is advisable. UVC has been shown to achieve a high level of inactivation of a close relative of the COVID-19 virus (i.e. SARS-CoV-1, tested with an appropriate dose of 254nm UV while suspended in liquid)[viii]. Scientists believe that similar results can be expected in the treatment of the COVID-19 virus, SARS-CoV-2. However, the key is to apply UVC in such a way that it can effectively reach all remaining viruses on these surfaces.
  • There is widespread agreement with CDC guidance for hospitals that the germicidal efficacy of UVC is influenced by the UVC-absorbing properties of the suspension, surface or aerosol in which the organism is located, by the type or spectrum of action of the microorganism, and by a variety of design and operational factors that affect the UV dose delivered to the microorganism (https://www.cdc.gov/infectioncontrol/guidelines/disinfection).


The scientific community recognizes that in cases where the UVC light cannot reach a particular pathogen, that pathogen is not disinfected. However, in general, by reducing the total number of pathogens, the risk of transmission is reduced. The total pathogen load can be significantly reduced by applying UV light to the many surfaces that are easily accessible, as a secondary barrier to cleaning, especially under hurried conditions. This would be a relatively simple matter of illuminating relevant surfaces with UVC light, e.g. the air and surfaces around rooms and personal protective equipment.

UV light, specifically between 200-280nm[i] (UVC or the germicidal range), inactivates (aka, "kills") at least two other coronaviruses that are close relatives of the COVID-19 virus: 1) SARS-CoV-1[ii] and 2) MERS-CoV[iii] [iv] [v]. An important caveat is that this inactivation has been demonstrated under controlled conditions in the laboratory. The effectiveness of UV light in practice depends on factors such as exposure time and the ability of UV light to reach viruses in water, air and in the folds and crevices of materials and surfaces.

Are UVC disinfection devices safe?

Like any disinfection system, UVC devices must be used properly to be safe). They all produce varying amounts of UVC light with a wavelength of 200nm-280nm. This UVC light is much "stronger" than normal sunlight and can cause a severe sunburn-like reaction on your skin. The target tissue in the eye would be the cornea (and not the retina). The effect on the cornea is called photokeratitis, which is also known as sweat flash or snow blindness, so it's like sunburn of the eye. It is unlikely that any of the UVC light will pass through the cornea and then the lens to reach the retina as it is a short wavelength (i.e. high frequency).

Some devices also produce ozone as part of their cycle, others produce light and heat like an arc welder, still others move during their cycle. Therefore, general machine and human safety must be considered with all disinfection equipment and these considerations should be addressed in the operating manual, user training and relevant safety regulations.

Are there performance standards and UVC validation protocols for UV disinfectors?

Given the wide range of UVC devices marketed for disinfection of air, water and solid surfaces, the lack of uniform performance standards and the widely varying degree of research, development and validation testing performed on different devices, the scientific community strongly recommends that consumers exercise caution when selecting devices and look for evidence of third-party testing and certification of device materials and electrical components by well-known organizations such as NSF, UL, CSA, DVGW-OVGW or other international requirements.

For UVC devices intended to inactivate air and solid surfaces in the healthcare industry,the scientific community is working intensively with national standards organizations in the lighting and healthcare industries to develop disinfection test standards[x]. The goal is to develop guidelines that will help healthcare providers worldwide select the best possible technologies for their facilities in the fight against multidrug-resistant organisms and other pathogens[xi], such as the COVID-19 virus.




[i] “Miscellaneous Inactivating Agents - Guideline for Disinfection and Sterilization in Healthcare Facilities (2008);” Centers for Disease Control and Prevention, National Center for Emerging and Zoonotic Infectious Diseases (NCEZID), Division of Healthcare Quality Promotion (DHQP) (https://www.cdc.gov/infectioncontrol/guidelines/disinfection/disinfection-methods/miscellaneous.html)

[ii] “Large-scale preparation of UV-inactivated SARS coronavirus virions for vaccine antigen,” Tsunetsugu-Yokota Y et al. Methods Mol Biol. 2008;454:119-26. doi: 10.1007/978-1-59745-181-9_11.

[iii] “Efficacy of an Automated Multiple Emitter Whole-Room Ultraviolet-C Disinfection System Against Coronaviruses MHV and MERS-CoV,” Bedell K et al. ICHE 2016 May;37(5):598-9. doi:10.1017/ice.2015.348. Epub 2016 Jan 28.

[iv] “Focus on Surface Disinfection When Fighting COVID-19”; William A. Rutala, PhD, MPH, CIC, David J. Weber, MD, MPH; Infection Control Today, March 20, 2020 (https://www.infectioncontroltoday.com/covid-19/focus-surface-disinfection-when-fighting-covid-19)

[v] Ibid.

[vi] “Preventing the Spread of Coronavirus Disease 2019 in Homes and Residential Communities”; National Center for Immunization and Respiratory Diseases (NCIRD), Div. of Viral Diseases (https://www.cdc.gov/coronavirus/2019-ncov/hcp/guidance-prevent-spread.html)

[vii] “New coronavirus stable for hours on surfaces”; CDC (extracted from N van Doremalen, et al. Aerosol and surface stability of HCoV-19 (SARS-CoV-2) compared to SARS-CoV-1. The New England Journal of Medicine. DOI: 10.1056/NEJMc2004973 (2020) (https://www.nih.gov/news-events/news-releases/new-coronavirus-stable-hours-surfaces).

[viii] “Inactivation of SARS coronavirus by means of povidone-iodine, physical conditions and chemical reagents;” Kariwa H et al. Dermatology 2006;212 (Suppl 1): 119 (https://www.ncbi.nlm.nih.gov/pubmed/16490989)

[ix] “Ultraviolet Radiation and the Work Environment (Revised. See: 74-121),” The National Institute for Occupational Safety and Health (NIOSH), Page last reviewed: March 29, 2017 (https://www.cdc.gov/niosh/docs/73-11005/default.html)

[x] “Pathway to Developing a UV-C Standard – A Guide to International Standards Development”, C. Cameron Miller and Ajit Jillavenkatesa, IUVA News / Vol. 20 No. 4, 2018

[[xi] “Healthcare Associated Infections Workshop Advances Development Of Ultraviolet Disinfection Technologies,” IUVA Press Release, dated 24 Jan 2020 4:14 PM (http://iuva.org/Projects-Articles-Repository/8672736)

Highly efficient disinfection UVC LED systems