A Language of Our Own
UV disinfection can be difficult to explain. There are many scientific terms, units of measurement, treatment methods, and product designs. Our goal in this UV glossary is to provide simple explanations for language that is common in our industry. If you have questions, please contact our UV applications specialists at (631) 273-0500 or email Sales@AtlanticUV.com.
Covalent Bond
A chemical bond formed between adjacent bases in the DNA during the process of microorganism inactivation. Read our FAQ.
Direct UV-C Disinfection
The process of directly exposing air and/or surfaces to UV-C rays. Unlike indirect disinfection, UV-C lamps are exposed. Thus, rooms must be unoccupied or personnel must be adequately covered.
Disinfection Chamber
In room air disinfection or water disinfection, the enclosed area in which the UV-C lamp performs germicidal treatment.
Dosimeter
A tool designed to measure the UV-C dose received by air/surfaces or people. Digital devices display a specific dose in nanometers. Cards or personal indicators change color to show an approximate dose has been received.
Electromagnetic Spectrum
The full range of electromagnetic radiation, divided up into different bands by wavelength.
Exposure Time
A certain amount of time in which direct UV-C rays are applied to air and surfaces in order to achieve the desired dose.
Far UV
A subset of the UV-C range produced by certain lamps, between 200 and 235 nanometers. Since these intensities do not penetrate as deeply into human skin as typical (254-nanometer) UV-C lamps, they are believed to be safer when distanced properly from people.
Germicidal Effectiveness
The ability of a UV-C frequency to inactivate harmful microorganisms. UV-C lamps at 254 nanometers are most effective at destroying a pathogen’s DNA.
Inactivation
A process where the DNA of a microorganism is prevented from being unzipped for replication. Inactivated microorganisms are neutralized or rendered harmless. Read our FAQ.
Indirect UV-C Disinfection
A process used to describe air disinfection that takes place safely and in occupied spaces. Examples are room air disinfection and upper air disinfection (also known as upper room UVGI).
Millijoule
1 one-thousandth of a joule, which is a unit describing energy (in this case, UV-C energy) delivered over a certain amount of time. Millijoules are used in labeling a UV-C dose.
Nanometer
A unit of length used to measure waves of light, particularly UV and visible light. Abbreviated as nm.
Pathogen
A virus, bacterium, mold, or other disease-causing microorganism. View our list of pathogens neutralized by UV-C light.
Point of Entry (POE)
The point where water enters a building. Point-of-entry UV-C purifiers disinfect water for an entire home, commercial, or industrial facility.
Point of Use (POU)
The point where water is dispensed for use. Point-of-use UV-C purifiers are installed closest to this point in the plumbing as possible.
Quartz Sleeve
A protective sleeve enclosing a UV-C lamp, mainly used in ultraviolet water purifiers.
Rated Lamp Life
An amount of hours during which a lamp’s UV-C output will be within the optimum range. Standard lamps have a rated life of 10,000 operating hours and should be replaced once per year.
Room Air Change
Usually calculated per hour and abbreviated ACH (for Air Changes per Hour). How many times the entire volume of air in a given space is replaced with supply and/or recirculated air. When UV disinfection inactivates 63% of infectious organisms in a room, one equivalent air change has taken place.
Room Air Disinfection
An indirect air disinfection method where air is drawn into a reflective UV-C exposure chamber and expelled back into the room. View our application page.
Sanitary Conditioner
An indirect UV-C air disinfection model that circulates purified air in the head space of a liquid storage tank.
Shortwave
Used to describe UV-C lamps, which use energy with a shorter wavelength than other ultraviolet lamps.
Total Suspended Solids (TSS)
The concentration of suspended particles in water, which include soil particles (clay, silt, organic matter), algae, and microscopic organisms. A TSS level of less than 10 mg/l meets the water requirements for UV disinfection. This concentration level goes hand-in-hand with turbidity.
Treatment Cycle
One of several spans of the proper exposure time needed for places where UV-C rays are obstructed from reaching the desired surfaces.
Turbidity
The measure of water clarity that determines UV-C transmission. In the UV-C industry, a turbidity level of less than 1 NTU meets the water requirements for UV disinfection. This concentration level goes hand-in-hand with total suspended solids.
Upper Air UV-C Disinfection
An indirect air disinfection method that safely projects UV-C rays across air in the upper portion of an occupied room.
UV
Short for Ultraviolet, it describes an entire section of the electromagnetic spectrum longer than X-rays but shorter than visible light. UV light is made up of UV-A, UV-B, and UV-C wavelengths, spanning 100–400 nanometers (see table).
| UV Type | Wavelengths (nanometers) | Alt Name |
|---|---|---|
| UV-A | 315–400 nm | Blacklight |
| UV-B | 280–315 nm | Sunlight |
| UV-C | 100–280 nm | Germicidal Light (GUV) |
UV LED
A UV lamp using a light-emitting diode instead of a traditional filament. These lamps produce wavelengths around 265 or 275 nanometers.
UV Wand
A hand-held UV-C device that should only be used while wearing proper protective gear (a face shield, gloves, and long sleeves).
UV-C Absorbance
The degree to which UV-C rays are absorbed by a certain liquid and unable to pass through the entire substance for disinfection.
UV-C Dose
An amount of UV-C energy, described in millijoules per square centimeter, delivered to water, liquid, or air/surfaces. An appropriate dose will cause inactivation of the microorganisms targeted.
UV-C Intensity
Overall power output of a UV-C lamp, expressed in watts.
UV-C Lamp
A lamp producing UV-C rays at 254 nanometers, the specific wavelength that is absorbed by a microorganism’s nucleic acid and leads to its inactivation.
UV-C Monitor
A device that measures UV-C output to determine whether a lamp’s output has decreased or a quartz sleeve is dirty.
UV-C Transmission
A measure of UV-C energy after it has passed through a solid (like a quartz sleeve) or a liquid.
UVGI
An acronym for Ultraviolet Germicidal Irradiation, usually used after “upper room” to describe upper air UV-C disinfection.
Wastewater
Water that has been used in the home, in a business, or as part of an industrial process. It may include human waste, food scraps, oils, soaps, and chemicals.
Water Test
A lab test designed to show the presence of harmful waterborne microorganisms.
Wavelength
A property of electromagnetic radiation, expressed in nanometers, which is used to organize the different sections of the electromagnetic spectrum.
