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As the HVAC industry continues to be concerned with finding ways to improve indoor air quality, ultraviolet germicidal irradiation (UVGI) is emerging as an effective method for killing microorganisms, including viruses and bacteria. UVGI technology works by emitting short-wavelength of ultraviolet light that damages the genetic material found in microorganisms, making them unable to reproduce. 

As a result, this antimicrobial process has been widely adopted across many industries looking to protect their customers from airborne pathogens. In this blog post, we will examine how UVGI works and discuss its effectiveness when it comes to improving indoor air quality within commercial buildings.

Explaining Ultraviolet Germicidal Irradiation (UVGI) and its Functionality 


UVGI is an effective strategy for germicidal control. Its functionality lies in the use of ultraviolet light — specifically UVC light as opposed to UVA and UVB, due to its high penetration capabilities — to damage the DNA of microorganisms, resulting in their inability to replicate. The wavelength of ultraviolet light is measured in nanometers, and its germicidal efficacy is maximized within a range of 200-230nm

In HVAC, the functionality of UVGI is to clean the air that passes through the system. HVAC system disinfection is a critical component of maintaining indoor air quality and reducing the risk of infection or disease transmission. And though it is important to maintain proper ventilation in any building, incorporating UVGI into the system can significantly increase the effectiveness of a building’s HVAC system, promoting healthy indoor air quality for building occupants.

UVGI is commonly used in hospitals, laboratories, and other settings where sterilization is crucial. It is a non-chemical approach to disinfection that does not produce any harmful byproducts, making it a safe and efficient solution. UVGI is an essential technology that is crucial in promoting public health and safety, particularly in environments where cleanliness and hygiene are critical.

Different Types of UVGI Systems and Their Applications 

Ultraviolet Germicidal Irradiation (UVGI) systems have been a viable option for sterilizing air, water, and surfaces for many years. Different types of UVGI systems exist, including low-pressure mercury lamps and high-intensity discharge lamps. These systems produce UV light in specific wavelengths to eliminate harmful microorganisms such as bacteria, viruses, and molds.

It’s crucial to choose the appropriate UVGI system depending on the application. For instance, the design of a UVGI system used in a hospital will vary from that used in a food processing plant. These systems are mainly used in commercial and industrial settings, and their efficacy in sterilizing surfaces and air has made them a go-to solution in many industries.

In one case, Donnelly Mechanical was tasked with upgrading an upscale fashion brand’s HVAC system in NYC’s Financial District — with the focus primarily on improving indoor air quality. To remedy the brand’s problems, Donnelly opted for a UVGI-based solution.

To do so, Donnelly Mechanical implemented a UVGI system on every floor of the office, mounted directly on the ducts. This system is specifically designed to disinfect the air as it flows through the HVAC system. Additionally, it irradiates the entire cross-section of the duct with high intensities, offering a comprehensive solution for the office building of this high-end fashion brand. 

Examining UVC Installations in an HVAC Setting

UVC light installations — like those offered at Donnelly — can be used in HVAC systems in two ways: disinfecting the in-duct airstream and disinfecting the surfaces of air handler components.

High-output UVC lamps are specifically designed to deliver UV doses for disinfecting the airstream. In-duct applications are easy to install and require minimal space, making them suitable for both existing and new equipment. These systems effectively disinfect the air as it passes through the HVAC system, reducing the presence of airborne infectious microorganisms that can cause illness. 

Additionally, UVC lamps can be used to target cooling coils, condensation pans, and filters for coil disinfection. By destroying bacteria and mold that grow on these surfaces in hard-to-reach areas, UVC lamps ensure a healthy air supply.

The Benefits of UVGI Technology 

The benefits of using UVGI technology are numerous, from providing a safe and healthy environment for building occupants to reducing the spread of germs and infections. UVGI is also an environmentally-friendly solution, as it doesn’t require any harsh chemicals or processes to be effective. 

When integrated into HVAC systems, UVGI technology can eliminate harmful microorganisms by disrupting their DNA and rendering them inactive. Using this technology not only benefits the health and safety of building occupants, but also ensures efficient HVAC performance by reducing the buildup of contaminants in air filters and ducts. Implementing UVGI technology in HVAC systems has become a vital aspect of building maintenance and design, particularly in high-traffic facilities, as previously stated.

As more research is conducted and the technology continues to evolve, UVGI is becoming an increasingly popular method of disinfecting and improving indoor air quality in commercial and industrial settings.

Scientific Evidence Supporting the Use of UVGI in Disinfection 

The use of UVGI in disinfection has been backed by a significant amount of scientific evidence. Studies have found that this method is effective in killing a wide range of microorganisms, including bacteria and viruses. 

A paper published in the National Library of Medicine (NLM) revealed that UVGI proved to have bactericidal effects on Methicillin-Resistant Staphylococcus aureus (MRSA) wounds, with 222-nm light eliminating skin damage as well. Additionally, another study shared by the NLM showed a significant reduction of airborne legionella bacteria using UVGI.

These are just a few examples of the growing body of evidence supporting the use of UVGI in disinfection. With the COVID-19 pandemic, UVGI has been increasingly implemented in healthcare facilities and other public spaces to combat the spread of infectious diseases. The promising results of these studies indicate that UVGI is a viable solution in maintaining a safer environment for everyone.

Potential Risks Associated with the Use of UVGI 

As with any technology, there are potential risks associated with its use that must be taken into consideration before implementing this solution.

One of the main risks in regards to UVGI in an HVAC setting is the potential for human exposure to UV radiation, which can lead to skin and eye damage. This risk can be mitigated by implementing proper safety measures, such as installing protective barriers and ensuring that only trained professionals handle the equipment. Additionally, improper installation or maintenance could lead to the emission of ozone, which can negatively impact indoor air quality and human health. 

Moreover, the effectiveness of UVGI in HVAC systems depends on several factors, including the dose of radiation delivered and the location of the UV lamps. When properly installed and maintained, UVGI can be a safe and effective way to improve indoor air quality. As with any technology, it is important to carefully consider the potential risks and benefits before implementing UVGI in HVAC systems, and to follow established safety protocols to ensure safe operation.

Tips for Proper Installation and Maintenance of a UVGI System

To ensure proper installation, it’s important to consult with a professional who can assess the space and determine the appropriate size and location for the UVGI system. Maintenance is equally important in maximizing the system’s effectiveness and lifespan. This includes regular cleaning of the UV lamps, monitoring the system’s performance, and replacing any worn or damaged parts. 

With proper installation and maintenance, a UVGI system can help reduce the spread of airborne pathogens within a facility, providing a safer and healthier environment for employees, customers, and visitors alike.

An Overview of UVGI

Ultraviolet Germicidal Irradiation (UVGI) is a very effective technology used for the disinfection of air and surfaces, with a long history of scientific evidence verifying its efficacy. There are various types available, each suited to different applications and space requirements. The benefits of this technology include improved air quality and reduced levels of illness due to harmful bacteria or viruses in a given area. 

On the other hand, if used incorrectly, it can present health hazards such as skin irritation or eye damage. It’s important to make sure that you choose the proper UVGI system for your needs, have it installed correctly, and maintain it properly according to manufacturer recommendations. 

UVGI Services at Donnelly Mechanical

If you’re looking for a comprehensive solution for your UVGI needs, look no further than Donnelly Mechanical. Here at Donnelly, we will assess your current equipment and space usage to determine the most suitable UVC application for your system. To learn more, please visit our website and get in touch with us today.

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