UV light sterilization, also called Ultraviolet Germicidal Irradition or UVGI, is not a new technology and has proven itself to offer substantial benefits when used for coil irradiation, air disinfection, and surface decontamination. It has become so clear that Ultraviolet C band light has been through so much testing that even the independant and non-comittal ASHRAE published in 2016 "the health benefits of UV-C are demonstrated by several studies. The technology is a potentially beneficial option that building owners should consider installing.”
UVC light was discovered to have usefulness back in the late 1800's and the first application of UVGI was for water treatment in the early 1900's and air disinfection in the 1920's. Yet we are still seeing current publications refering to it as new
such as Healthcare Facilities Today in a February 2017 article. In the article (available here) there are 13 different peer reviewed studies referenced that all were published between 2010 and 2017, each one verified the effectiveness of uv c in several different applications.
So Why Is This Still Considered a New Technology?
It seems to stem from not the technology, UVGI, but rather how it is applied. The applications of UVC right now can be grouped into three broad catagories:
- Coil Irradiation
- Air Disinfection
- Surface Sterilization
Coil Irradiation in HVAC systems was first installed in 1996, and there are articles published routinely expressing how quickly it works and how inexpensive it has become.
A couple that were recently published were a multi-year study done at Los Angels Internation Airport in theNews which showed a maintenance savings of $900/year/AHU on top of the energy efficiency, 15% or more better airflow after just a few weeks, and an installation cost of 15 cents/cfm or less. Plumber Magazine looked more at how this application works, answering the question what is UVC, and found that energy efficiency is improved by 10-25%
UV Air Disinfection was first used in the 1920's to help control the spread of airborne pathogens, at the time Measels and Tuberculosis were the main concern. Today these pathogens are mostly under control while this application limits the spread of Influenza and the common cold.
UV Light Sterilization of surfaces is one of the newest applications. Many different manufacturers have started making towers and robots that are wheeled into a room and turned on for between 15 and 30 minutes. The cost of these machines is usually over $90,000 but budget towers can be purchased for about $40,000. Due to the high price tag, it is these systems that have drawn the most focus as the manufacturing companies are spending a ton of money sponsoring studeis to prove just how great their product is. It is not doubted that UVC light works to sterilize surfaces, but the efficacy of these towers is questionable as they are subject to exponentially decreasing effectiveness the further from the lamp the surface is and shadowing caused by other objects in a room.