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Advancing the sciences, engineering & applications of ultraviolet technologies to enhance the quality of human life & to protect the environment.

Advice for the selection and operation of equipment for the UV disinfection of air and surfaces

The International Ultraviolet Association (IUVA) is a non-profit association bringing together scientists, engineers, ultraviolet (UV) manufacturers, consultants and others with an interest in safe and effective treatments using UV light. IUVA has received many inquiries recently, as a result of the COVID-19 crisis, as to a whether or not IUVA has advice for the selection of and use of UV disinfection systems for the healthcare industry. This list is intended to provide advice for those who are thinking of purchasing UV disinfection equipment. These tips should only be considered as suggestions.

Although the content of this document will have relevance in some sense around the world, it has been prepared largely for the North American market.

  • Buyer beware! – there are few accepted standards for equipment designed for the UV disinfection of air and/or surfaces. As a result, there are many ads and promotions that claim amazing performance with little or no scientific backup.
  • Ask the vendor for copies of scientific papers documenting that their unit will actually work as they claim. The scientific paper(s) should show actual reduction of a test microorganism in the environment that the unit is supposed to operate.
  • Is the company registered with the US Environmental Protection Agency (EPA) as a pesticide device producing establishment? See the website (https://www.epa.gov/compliance/national-list-active-epa-registered-foreign-and-domestic-pesticide-andor-device-producing)
  • Does it have appropriate built-in UV safety sensors for automatic shutoff or is safe operation totally reliant on the operator?
  • Does the device meet NIOSH, UL, IEEE and related safety standards?
  • Does the device emit/generate ozone? If so, is it compliant with NIOSH requirements. How is the ozone mitigated? (We suggest avoiding ozone devices, as it is a safety hazard for operators, unless ozone is specifically part of the treatment process and is applied in a controlled and safe way)?
  • Is the device being used to disinfect medical devices? If so, is it compliant with US Food and Drug Administration (FDA) requirements (see FDA document 21CFR 880.6600)?
  • If the device is a UV wand used to disinfect a surface (e.g., countertop or an envelope):
    • The technical specifications should give 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 the exposure time in seconds) should be at least 40 mJ/cm2 to inactivate viruses on perfectly flat and ideal surfaces. So if the irradiance at the target surface is 10 mW/cm2, the exposure time would have to be 4 seconds. However, the presence of microscopic crevices on flat surfaces can inhibit the disinfection, and disinfection on other materials such as cloth may require wholly different doses. For example, the disinfection of viruses on protective medical masks may require doses in the order of 1000-3000 mJ/cm2. This is an issue that is currently being researched and our current understanding is changing almost daily.
  • With any UV device, DO 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 “line-of-sight” between the UV lamp and the target surface. If the UV beams are shadowed by elements of texture on the surface, the shadowed sections may receive much reduced UV light or no light at all. The disinfection efficacy will therefore be determined by the UV dose that these sections are exposed to.
  • Like any disinfection system, UVC devices must be used properly to be safe.
    • They all produce varying amounts of UVC light in wavelengths of 200 – 280nm. UVC light is much more energetic than normal sunlight, and can cause a severe sunburn-like reaction to your skin, and similarly, could damage the retina of your eye, if exposed.
    • Some devices also produce ozone as part of their cycle, others produce light and heat like an arc welder, others move during their cycles. Hence, in general machine-human safety needs to be considered with all disinfection devices
    • These considerations should be addressed in the operations manual, in the user training, and appropriate safety compliance.

Disclosure

The International Ultraviolet Association (IUVA) provides this advice as suggestions only; IUVA cannot be held responsible for any application or misuse of this advice.

Note:The information provided here is believed to be current at the date of publication. The statements found here may not cover all applicable information. IUVA is not responsible for the conditions of use of particular UV equipment. It is the user’s responsibility to determine the safe conditions of use. This information is offered in good faith and is believed to be reliable; however it provides neither warranties nor representations. IUVA disclaims any and all liability for the damages incurred directly or indirectly through the use of this document. Nothing contained herein should be considered a recommendation or endorsement. Contact your supplier for additional information.

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