Get Answers to Common UVC Questions from the Manufacturer
Whether you are familiar with UVC technology or just getting started on your own research, it can be difficult to find reliable sources of information. Our experts at SARIN wanted to make your life easier by compiling a list of the most common questions we encounter.
As always, we are happy to answer any specific questions not covered in this list. Just give us a call or send an email to find out more.
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There are three types of UV radiation (between 10-400 nm), which are classified according to their wavelength.
Short-wavelength UVC (100–280 nm) is the most active type of UV radiation. Naturally, UVC is blocked by the atmosphere and does not reach the earth's surface. The shorter the wavelength, the more harmful the UV radiation. However, shorter wavelength UV radiation is less likely to penetrate the skin.
Medium-wavelength UVB (280–315 nm) is very damaging but cannot penetrate beyond the superficial skin layers. It is responsible for delayed tanning and burning. In addition to these short-term effects, it enhances skin ageing and significantly promotes the development of skin cancer.
The relatively long-wavelength UVA (315–400 nm) accounts for about 95% of the UV radiation reaching the Earth's surface. It can penetrate deeply into skin and is responsible for the immediate tanning effect. It also contributes to skin ageing and wrinkling. Recent studies strongly suggest that it may also enhance the development of skin cancers.
With proper PPE that covers the eyes and skin, operating a UVC device is completely safe. Without any PPE, prolonged or direct exposure to UVC light can cause temporary eye irritation and skin redness, but has not been shown to cause skin cancer or cataracts.
We recommend only using devices with built-in safety features and clear instructions. UVC is safer than UVA and UVB and has not been shown to cause cancer or cataracts but can still cause redness and irritation. SARIN follows FDA and CDC guidelines as strictly as possible. It is recommended that when using larger UVC devices you should leave the room to avoid prolonged exposure.
UVC is an complex combination of science and mathematics. The three factors that determine an effective dose of UVC for sterilization are:
- UV light intensity
- Distance from light source
- Exposure time
If you increase distance, you have to increase intensity or exposure time. It is not a 1:1 ratio, for example: with room sterilization, if you double the distance you can't just double the exposure time.
SARIN testing has allowed us to make specific instructions regarding where and how to use each product. We choose to err on the side of caution and are highly conservative when it comes to recommendations.
Any living cell that is exposed to UVC light will be affected—including viruses, bacteria, yeast, mold, algae, amoebas, and allergens.
The UVC energy penetrates outer layers of a cell and is absorbed in the DNA or RNA, damaging nucleic acids. Once nucleotides are fused, a microorganism is inactivated by losing its ability to reproduce and infect. This entire process happens within seconds of adequate UVC exposure.
Simple-structure organisms like viruses and bacteria are the most vulnerable to ultraviolet light, whether they are airborne or on a surface.
This is a question that scientists are racing to answer, but testing is still preliminary. Extensive testing has been used to prove that UVC effectively disables similar viruses in the SARS family. It is believed to have the same effect on the Coronavirus. COVID-19 (SARS-CoV-2) has an enveloped structure and single positive-stranded RNA genome, which have been found to be particularly vulnerable to UVC. SARIN is in the process of finding a BSL-3 lab with access to SARS-CoV-2 cultures for testing but has not been able to establish a timeline.
For more information on the effects of UVC on Covid-19 view this article.
UVC has been proven to reduce incidences of infection during clinical trials for: MRSA, VRE, C. diff, K. pneumoniae, hepatitis A & E, influenza, rhinovirus, enterovirus, human metapneumovirus, and more.
The ability of UVC light to penetrate materials depends on their chemical composition.
Most acrylic plastics (Even very thin acrylic sheets of less than 5 mm) allow light of wavelengths greater than 375 nm to pass through but not UVC.
Normal glass (windows) are transparent to UV above 330 nm (UVA). Below 330 nm (UVB and UVC), almost 100% is blocked by typical glass.
- UVC should not be used on humans, plants, or animals
- UVC can degrade natural pigments found in decorations like paintings
- UVC can mildly shorten the shelf life of some plastics
- You can use UVC on food – it extends shelf life with no damage to quality or nutrition
- UVC is excellent for disinfecting hard surfaces, objects, and the air
- Hypoallergenic and residue-free cleaning is great for personal items like eyeglasses, masks, and electronics
Over long periods of time, UVC has been found to slightly degrade plastics. UVC can also have an effect similar to sun-bleaching on objects with natural dyes and colors after prolonged exposure.
UVC itself does not produce any harmful chemical residue. Untreated UVC bulbs do however generate ozone, which has been shown to be toxic in high amounts.
All SARIN brand bulbs for open-air devices have been titanium doped to ensure that no ozone will be generated. After running a UVC cycle, there will be an odor due to the breakdown of organic matter. This odor is not ozone and is more prominent in areas commonly used by people and animals, but will rapidly dissipate.
All low-pressure mercury lamps emit at least two frequencies, one of which generates ozone, which is harmful to breathe. When the glass of a lamp is “doped” with titanium the 185nm wavelength that creates ozone is blocked.
Ozone is a highly toxic chemical in large doses. It does a good job of disinfecting nooks and crannies that UVC light cannot reach, but should be used with caution and only in rooms with accessible ventilation. For most applications, UVC light used at a variety of angles is enough to disinfect an area.
UVC has been shown to have a significant impact on disinfecting viruses and bacteria when used alone. Using traditional cleaning methods before the UVC enhances the effectiveness, as UVC has better results when the area is free of dust and debris. However, UVC is not meant to be a replacement for normal sanitary practices.
Most of the energy produced by the lamps is UVC. Devices also emit a blue hue as an indicator to help you see what areas the UVC is disinfecting.
It is important to note that UVC only disinfects the areas that the light can touch. UVC test strips can be purchased as a visual indicator that the lamps are working properly. Aside from that, it’s difficult to test without a UVC radiometer or culture test trays.
For more information about the effectiveness of UVC in areas the light touches & shadows read this article.
The best way to know whether or not to trust if a UVC device is legitimate is by requesting a scientific test report. Third-party laboratories have access to advanced equipment and run experiments in controlled environments.
It is a good sign if a product is covered under warranty. Higher quality devices generally also have more certifications and safety listings.
The reason UVC product quality varies so widely is because standards are still being established and this industry is not highly regulated. This allows ineffective and even fake UVC products to flood the market. Warning signs of an inferior product include:
- Products that do not list UVC output intensity
- Products which mention intensity but neglect the distance from which it was measured
- Products which have not been tested in a laboratory to validate effectiveness
- Products with poorly written or vague instructions
- Products with a lack of proper certifications and safety listings
- Products missing critical safety features like motion detectors, timers, gravity sensors, etc. (What is considered critical varies depending on model type)
- Products on eCommerce websites from companies that don’t have a clear background, website or storefront
- Products with unclear and incomplete specification sheets. (Such as failing to specify the bulb sleeve material, as it could likely be cheap soft glass which is less durable and effective than quartz or fused silica)
- Companies that do not offer warranties or have a strict return policy
- Companies that can’t specify what components are used and why, and don’t know what they are selling because they are not manufacturers
- Companies that include misleading information in marketing material (like bogus claims or photos showing a device used on pets and objects being held)
- Companies with reluctant, slow, or unknowledgeable customer support
UL and ETL Safety Certifications
There is no UL or ETL classification yet for UVC devices, however individual components (like drivers) in high quality products are typically either UL or ETL listed. This is uncommon for UVC devices. SARIN is one of the only companies to have an entire fixture ETL listed.
Food and Drug Administration
Due to the pandemic, normal requirements have been waived, but SARIN is still pursuing the application process to get listed with the FDA. All the components are FDA compliant.
Environmental Protection Agency
EPA compliance guards the nation's environmental laws to help protect public health and the environment. All SARIN products have a registered EPA number.
CE: Health, safety and environmental standards for products sold in Europe.
FCC: Federal Communications Commission finds no electromagnetic interference.
RoHS: Environmental directive for Restriction of Hazardous Substances.
Get more information about UL Certifications and UVC.
In most cases, UVC lamps do not need to be cleaned. If cleaning is necessary, use a paper towel or a dry lint-free cloth and alcohol. Do not touch the bulbs with your hands, as the oils in your skin can degrade the quality of the bulb.
The EPA has detailed specific guidelines for the cleanup of broken bulbs which contain mercury:
- Have all personnel leave the room or area
- Open a window or air out the room for 10 to 15 minutes
- Disable your HVAC system, if applicable
- Carefully scoop up all shards of glass, powder, and metal filaments using a stiff piece of cardboard
- Vacuum up any remaining powder or particles
- Place all cleanup materials, including any used vacuum cleaner bags, in a sealable container or trash bag, and leave them outside until the debris and materials can be disposed
- Contact a local recycling company or take all materials to a drop-off location to dispose of the broken bulbs
Consumers should conduct their own research because the data speaks for itself. There are a lot of helpful resources out there and articles are constantly being published. Most devices fall into three categories: containers for small objects, wands for targeted applications, and full room sterilizers.
Of course, we are always happy to answer questions for anyone that doesn't know where to start. If you would like to request a quote send us a message.