Spotlight Blog

The ABC’s of UV Light

Oct 7, 2020 | Products

Welcome to The Lighting Agency’s four-part series on UV Light with a focus on how PURO™ Lighting, powered by Violet Defense™ can be installed as an integral part of your facility’s complete cleaning system.

We’ve been fielding a lot of questions from all of you about PURO™ Lighting over the last few months. And with all the recent media attention, and heightened public interest surrounding the application of UV light technology, we thought this would be a perfect time to delve into this hot topic on the TLA Spotlight Blog.

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In this first installment, we’re going to talk about what UV-A, UV-B, and UV-C are and how you can safely and effectively utilize UV light. This up-to-date, science based information is brought to us in partnership with our friends at PURO™ Lighting.

How do you select the best UV Lighting System for your needs?

Sunlight has been killing germs since the beginning of time, but we are just now beginning to fully tap into this proven cleaning power indoors. Scientists have long known that the ultraviolet spectrum, aka UV light, is an effective tool for protecting your facility from harmful pathogens.

UV disinfection systems are designed to help protect people against dangerous pathogens that can cause unnecessary illnesses and even deaths. However, an effective germ-killing system must also ensure that safety is of utmost importance. Before utilizing this technology, it is important that buyers educate themselves to ensure they purchase solutions that are safe, proven and effective.

What are the 3 different UV light waves?

According to the World Health Organization, there are three types of UV radiation, classified according to their wavelength. The three primary bands of the ultraviolet spectrum are: UV-A (320-400 nm), UV-B (280-320 nm), and UV-C (100-280 nm). They differ in their biological activity and the extent to which they can penetrate the skin.

UV Radiation Types

Long-wavelength UV-A accounts for approximately 95 per cent of the UV radiation that reaches the Earth’s surface. It can penetrate into the deeper layers of the skin and is responsible for the immediate tanning effect. Unfortunately, it also contributes to skin ageing and wrinkling. For a long time it was thought that UVA could not cause any lasting damage, however recent studies suggest that it may enhance the development of skin cancers.

Medium-wavelength UV-B is very biologically active but cannot penetrate beyond your 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. Most solar UVB is filtered by the atmosphere.

Short-wavelength UV-C is the most damaging type of UV radiation. Normally, it is completely filtered by the atmosphere and does not reach the earth’s surface.

A safe, effective installation must account for the potential risks and benefits of UV light to the facilities occupants. The spectrum(s) of ultraviolet you may utilize to help sanitize your facility may vary depending on factors such as usage and traffic patterns, as well as the types of pathogens you wish to target. Thoughtful and deliberate lighting placement is essential for a safe and effective install.

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Why does installation location matter?

Not only does the distance of a UV light source from the targeted area of disinfection matter, but the location of that light source will also impact its effectiveness in eliminating pathogens. There is much discussion over the relationship between shadowing and UV disinfection technology, which can require multiple devices within a room and/or extended run times to ensure enough UV dosage is delivered to areas not in direct line of sight. Installations that do not provide effective coverage—due to incorrect angles of placement on textured surfaces for example—can inadvertently support pathogen growth, a phenomenon known as the “Canyon Wall Effect.”

Read more about the kill rate of UV lighting and the “Canyon Wall Effect” here on the PURO™ Lighting website.

What makes PURO™ Lighting, powered by Violet Defense™, an ideal choice for effective disinfection utilizing full spectrum UV light technology?

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1. Full-Spectrum, Chemical-Free Cleaning UV light does not release any chemicals into your environment, nor leave any chemical residue behind after applications. The full-spectrum wavelengths employed help protect against:

  • Coronavirus
  • C. auris
  • C. diff
  • E. coli
  • Norovirus
  • MRSA
  • Salmonella

2. Does not emit O3 –  UV devices do not directly emit the ozone, regardless of bulb type. Rather the ozone is actually created when ultraviolet radiation, typically below 240 nm (produced by any source) interacts with oxygen in the air. The peak creation of ozone occurs at 185 nm. While low pressure mercury bulbs do not have a peak at 185 nm, they may still produce some ozone (though certain models may specifically block this wavelength if bulb is made of glass or fused quartz doped to block radiation below 200 nm).  UV light itself (240-280 nm) can also destroy ozone, with peak absorption at 254 nm, thereby self-limiting the net ozone creation While high levels of ozone have been linked to health concerns, “in general the levels (of ozone) produced are low, the concentrations dilute, and these byproducts of the UVGI process tend to break down or dissipate rapidly”11. The half-life of ozone is only about 15 minutes in the air.

3. Economical and Environmentally Friendly – PURO™ Lighting, powered by Violet Defense™, utilizes “miniaturized” technology for minimal environmental impact during the manufacturing process, is portable and can be plugged in to a standard 110v outlet.


TLA is here to help answer your location-specific questions and navigate the process of identifying, installing and implementing the best UV Light System for your needs using PURO™ Lighting, powered by Violet Defense™. Contact your TLA sales representative or our inside lighting sales team at for more information on any of the products above.

You can also check out the EVENTS section in this newsletter or click-over to our website EVENTS page for upcoming trainings, seminars and virtual tradeshows.

Be sure to join us for the next three parts in this series as we cover:

  • Disinfection in Schools and Universities
  • Healthcare Applications
  • The Value of Green Cleaning


Additional Resources…

We’d like to invite you to explore our newly re-designed website, which we hope will become a go-to resource for all your professional lighting needs.

TLA has added an EVENTS page where you can access and register for scheduled and on-going virtual presentations, seminars and trainings for a full spectrum of lighting topics ranging from controls, to design, to products.

Checkout our new Quick Quote Tool to help designers stay on budget.

Are you looking for an efficient way to stay current on all things lighting? Subscribe TLA’s bi-monthly newsletter here.


Thank you so much for joining us today on the blog!


The Lighting Agency is a local construction allied company representing the premier lighting and controls manufacturers for Colorado and Southern Wyoming. We strive to be an integral part of the design process through our work with lighting specifiers, contractors, suppliers, and owners to create brilliant yet budget-sensitive results for projects big and small.