What's the Difference Between UV-C and Far-UVC?
WHAT IS UV-C?
Scientists discovered UV-C (also called germicidal UV) more than a century ago. Since then, it's been studied and used in applications like water treatment and preventing the spread of pathogens in hospitals.
The UV-C spectrum includes wavelengths from 200 to 280 nanometers. These wavelengths are known for the ability to eliminate 99.9% of pathogens, such as viruses, bacteria, fungi, and mold spores.
Most traditional UV-C products (like low pressure mercury lamps) use energy from the 254 nm wavelength because scientists found it the most effective. UV-C LEDs, which are relatively new to the market, are generally 260 to 280 nm. Other products use broad spectrum UVC, which is a combination of wavelengths found in UV-A, UV-B, and UV-C ranges.
Recently, scientists found UV-C light can kill SARS-CoV-2, the virus that causes COVID-19. More businesses have started to add UV-C products to protect their employees, tenants, and customers.
Pros of UV-C
Fast disinfection – UV-C products can inactivate pathogens in minutes. Even a five minute cycle will help eliminate viruses and bacteria. Even though UV-C products work quickly, you should always take into account several factors like intensity, distance, and time when you're finding the right UV dose.
Proven track record – Study after study for the last century has proven that UV-C light can disinfect air and surfaces. Hospitals and medical buildings have used UV light for decades. It's helped reduce transmission and gotten rid of some of the hardest to kill bacteria. Experts in the lighting industry, like the Illuminating Engineering Society, agree that UV-C is effective and safe when used correctly.
Multiple applications – There are multiple applications for UV-C and they all work a little differently to disinfect air and surfaces. Products like upper room UV-C fixtures and UV lights for HVAV equipment target air disinfection and help reduce transmission of pathogens. Products like UV-C fixtures and mobile UV units target surfaces in rooms or areas. There are most likely UV-C products that will work for your business
Cons of UV-C
Harmful to skin and eyes – The biggest drawback of UV-C products is you can only use it in unoccupied rooms or areas. UV-C products can burn the skin and eyes. There are certain products, like upper-room germicidal UV and HVAC UV products, that can safely eliminate pathogens in occupied areas. However, caution is still required for the maintenance of those products.
WHAT IS FAR-UVC?
Researchers started focusing on far-UVC in the last decade. Far-UVC uses a lower range of wavelengths (between 207 and 222 nm) for disinfection. Most far-UVC products contain 222 nm light.
When you ask experts in the lighting industry about far-UVC, there is mixed reaction. Some experts believe far-UVC is safe for humans. Others say there is not enough evidence to back up those claims.
Pros of far-UVC
Safe for skin and eyes – According to most research, far-UVC products are safe for skin and eyes. Far-UVC does not penetrate the outer layer of skin or eyes, so it doesn't cause any tissue damage.
Constant disinfection – Because far-UVC is safe for skin and eyes, products can run constantly. They can work at all times to kill pathogens like viruses and bacteria so you are never starting from ground zero. UV-C products only target germs during a timed cycle when no one is in the room.
Cons of far-UVC
Limited testing – The biggest concern from industry experts about far-UVC is limited testing on humans. Although studies on mice show no long term effects, there are no studies on the long term effects on humans.
Slow disinfection – Right now, there are limits to the amount of UV energy in a space, which requires far-UVC products to operate at a very low dose over a long period of time. For example, the Healthe SPACE™ is a downlight delivers a dose of 23 mJ/cm² over the course of an eight hour day. That is the dose delivered to a surface three feet below the downlight. 23 mJ/cm² is the threshold limit value for occupied spaces.
Limited product offering – Because far-UVC technology is so new, there is limited product offering. There are only a few manufacturers producing far-UVC products, and you want to make sure you choose a trusted and reputable manufacturer. Even manufacturers producing far-UVC only have a few fixture options. This is likely to change in the next few months and years.
UV-C PRODUCTS VS. FAR-UVC PRODUCTS
Now that you know the pros and cons of UV-C and far-UVC, how do they really stack up against each other?
Here's a comparison chart:
Safe for skin and eyes
We will most likely see more far-UVC products on the market in the months and years to come as more manufacturers focus on the technology. Scientists are continuing their research into safety.
Meanwhile, UV-C products continue to be a solid and reliable source of disinfection for a wide range of industries, including hotels, retail stores, restaurants, schools, and more.