UVC: How it works

GermFalcon kills bacteria and viruses using high doses of Ultraviolet-C light.

[To avoid redundancy I will use “sanitize” and “disinfect” interchangeably. They both mean kill all the germs. The difference is negligible with regards to me, you, this post or anyone but a high-maintenance microbiologist. For you, Doctor: By “all the germs,” I mean greater than 99.9%.]

We all know about “germs”. Specifically they’re bacteria and viruses that get you sick.

Ultraviolet Light

You’ve probably seen the visible light spectrum before; on the spectrum, visible light (violet to red) is from 380 nanometers to 780 nm. As a reference, most household lamps are between 500 and 700 nm.You may also be familiar with UVA and UVB (280nm-400nm), related to suntans and sunburns and used in tanning bed applications.


It is generally agreed upon that 254 nanometer UVC is optimal for germ-killing purposes.

Why does UVC work?

At the foundation of a suntan or sunburn is skin cell damage caused by Ultraviolet-A and -B rays given off by the sun. UV rays are harmful. SPF 30, Earth’s atmosphere, and evolution have allowed us and most organisms to develop a tolerance to moderate levels of UVA and UVB. That’s the big difference.

The sun gives off UVC, too, but it’s not strong enough to penetrate Earth’s atmosphere. So, there’s been no chance for infectious bacteria and viruses to develop a similar immunity. Hospitals use UVC to kill germs because its germicidal characteristics can be unequivocally relied upon.

Who uses UVC?

UVC is commonly used in hospitals, air and water filters, microbiology labs, etc. They rely on high strength UVC for disinfecting because it works. It kills germs quickly and effectively. UVC rays attack DNA and paralyze all cellular functions. Bacteria, viruses, and even antibiotic-resistant superbugs have no tolerance to UVC. UVC=dead, that’s it. The germs are dead and unable to contaminate samples or be “caught” by a patient in a hospital.345_uvc_on_dna


UVC bulbs, our geeks insist “lamps”,40yolight are long linear cylinders–like the flourescent bulbs in a high school computer lab or that scene from that one movie.

Effectiveness is a function of UVC strength and exposure time.

Lamps are normally positioned at short distances from the “target disinfectee” because it works most effectively in the lamp’s line of sight.

“Line of Sight”

So imagine 2 parallel lines. One is a UV-C lamp, the other is the target surface we want to disinfect.slide1Using a high dose of UV-C is important because strength and effectiveness drop off at further distances. Therefore, the closer the target the more effective the kill.slide2At greater distances, UV-C strength and effectiveness drop off quickly. slide7
Now imagine the same 2 lines, perpendicular. slide5
A vertical lamp is sub-optimal for horizontal surfaces. The lamp is not “aiming” at its target, so the exposure is spread across the surface. Since the strength drops off further from the lamp, you would have to increase time. It works, but it takes longer and there’s no guarantee of sufficient exposure to a contaminated area.

UV-C does not penetrate any solid surface or material. If an object is in the lamp’s line of sight, it will completely block any exposure to the covered area of a target behind it.
Additionally, UV-C does not reflect off any surface. We have heard claims that low levels of UV-C reflect off walls, curtains, screens, etc., so increasing time can sufficiently sanitize surfaces of a full room. UV-C works only line of sight. Reflecting off a wall expecting effective levels of UV-C to bounce back is a fallacy.

The GermFalcon Application: Mobility and Versatilitythree-modes

We’ve positioned GermFalcon UVC lamps strategically to expose as many surfaces to the highest dose of UVC we can produce. GermFalcon’s wings give it unique versatility. Lamps are positioned vertically, but as the operator extends the wings, angles of the lamps change.

The operator can control the wing positioning vertically and horizontally to optimize exposure to targeted areas and ensure an adequate kill.

GermFalcon is mobile and easily maneuvered by a certified operator. An operator can expose surfaces to high levels of UVC at close distances and a variety of angles. slide8
If an object is blocking a target disinfectee, the operator can extend, retract, or re-route around it as needed. By moving over a horizontal surface with lights directed downward at varying angles, GermFalcon can thoroughly expose walls, tables/counters, shelves, corners, floors, and reverse sides–without relying on imaginary low-level reflection rays bouncing off the walls.

Please ask questions!


This slideshow requires JavaScript.

Designing something that could be safe, effective and convenient was our goal–and I think we nailed it. Writing this blurb was a fun exercise for me. It’s my first try so please leave some feedback, questions, or comments. If there’s anything I left out, I apologize. I will get better. If you ask questions, maybe it will be the topic of a future post.

Your buddy,

Elliot Mo K.

One thought on “UVC: How it works

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s