Visible light technology

by brittney_cutler | June 8, 2022 4:00 pm

[1]By Cliff Yahnke, PhD

The COVID-19 pandemic and its subsequent variants have focused the public’s attention on infectious disease and its transmission. While this has always been an important consideration in acute healthcare, it has become increasingly important in non-healthcare applications, such as education, commercial offices, indoor sports venues, retail spaces, and other congregate settings.

While the recommended mitigation for disease transmission is vaccination, there are other precautions, such as physical barriers (masking), distance (social distancing), and limiting the time of exposure. Each of these methods are impactful.

The role of the environment in disease transmission through contaminated surfaces or contaminated air is well established as a matter of general principle, beginning with the father of modern surgery, Joseph Lister (“It is not the air, it is something in the air”). Subsequent observations that sunlight heals wounded soldiers by Florence Nightingale in 1863, and that sunlight kills tuberculosis (TB) by Robert Koch in 1890, formed the basis for the commonly understood principles of ultraviolet (UV) disinfection today.

Reducing the bioburden

Bioburden primarily comes from people shedding microbes from their bodies (e.g. face, hair, and hands) and clothing, especially shoes. It is spread by people touching, moving, and working. Bioburden travels on equipment, materials, bags, tools, and anything being transferred from point to point. Sanitization or cleaning with an effective disinfectant is critical to all surfaces and equipment.

The pandemic has proven the importance of reducing the bioburden between regular sanitation and cleanings. Now with students back in classrooms, and employees returning to their workplaces, it is more vital than ever to mitigate viral transmission.

Not all germicidal lighting is created equal

[2]

The pandemic has spurred tremendous interest for any products that can mitigate harmful pathogens, including whole-room germicidal lighting. Not all germicidal lighting is safe for humans, and knowing the differences is critical. There is evidence demonstrating the persistent contamination of environmental surfaces despite traditional cleaning and disinfection methods. This risk has led to the widespread need for reassessing traditional cleaning protocols and for using secondary disinfection technologies[3].

UV disinfection is a type of no-touch technology which has shown to be a successful adjunct to manual cleaning in reducing environmental bioburden. Unfortunately, there is no government oversight for the safety of systems using UV or visible light to disinfect. The Food and Drug Administration (FDA) regulates the use of medical devices whose primary intent is to treat people, the Environmental Protection Agency (EPA) regulates the use of chemical disinfectants, and Occupational Safety and Health Administration (OHSA) focuses on ionizing and/or coherent radiation. Fortunately, there is a well-established international standard, International Electrotechnical Commission (IEC) 62471 which covers the safety of UV and visible light based on human and animal injury data. Using the IEC classification, all UV lighting is assigned a risk level, whereas 405 nanometer (nm) visible light is classified as ‘risk exempt,’ meaning it is safe for room occupants.

Due to potential health hazards, the use of UV light in occupied spaces is extremely limited at this time. Considering the current pandemic, however, several manufacturers are attempting to create new standards designed to specifically mask UV’s potential hazard by engineering the room into two parts[4]. The hazard is assessed in one part but ignored in the other, creating confusion for potential users. From there, responsibility for the safety of the entire installation is pushed onto the installer/contractor, who is sometimes not capable of making this assessment, through no fault of their own.

[5]

Scientists and engineers have developed technology using 405nm visible light to provide safe disinfection around the clock, without manual intervention even when people are present. These luminaires safely and automatically kill harmful organisms, such as viruses, bacteria, molds, yeast, and fungi in the air and on surfaces, without the need for specially trained staff.

Specifically, 405nm visible light is both direct and indirect; reflecting off walls and other surfaces where it kills pathogens in shadowed areas where UV lighting does not reach. The efficacy of 405nm antibacterial light has been proven against multiple species of viruses, bacteria, fungi, and spores, with no degradation of equipment or materials, in high-volume and high-stakes active environments[6].

Rather than relying solely on staff to clean surfaces, or HVAC systems to purify the air, this patented technology combines the benefits of both. Using the visible light spectrum, this technology is safe at all times-even when performing at its highest level of disinfection. As a result, this means there is no room downtime, and no worries about safety. Additionally, because 405nm visible light disinfection is extensively validated in healthcare, its efficacy and usefulness extend to non-healthcare applications.

Visible light in action

University of Massachusetts-Amherst (UMass), Amherst, Massachusetts

Cultivating a healthy relationship with fitness for personal well-being is vital for every individual—especially college students. According to research published by Harvard Medical School:

∞ Approximately 67,000 college students from 100 colleges and universities showed high rates of stress.

∞ One out of four students were either diagnosed with, or treated for, mental health issues.

∞ One-fifth of students have considered suicide and 20 percent reported self-injury[7].

Research from Michigan State University has provided a link between exercise and students achieving higher grade point averages (GPAs). In addition, students who had gym memberships[8] were less likely to drop out of school.

When UMass physical plant engineers updated the lighting at Boyden Gymnasium in 2019, their goals were to replace the fluorescent lighting with light-emitting diode (LED) luminaires to help reduce energy consumption and improve the lighting quality throughout the facility. The athletic department had an additional request: the new LED fixtures for specific areas had to utilize visible light disinfection technology which, in addition to illuminating the space, could be used to kill harmful germs and bacteria, such as Staphylococcus aureus (staph), including Methicillin-resistant Staphylococcus aureus (MRSA), as well as SARS-CoV-2 and Influenza-A.

Exercise facilities have been considered ‘high-risk’ for transmission because of their enclosed environment, shared equipment, and close contact between users and staff. After the pandemic hit, UMass discovered the added benefit of the disinfecting luminaires: students feel more protected at the gym knowing the lights could kill SARS-CoV-2.

“The students and staff are very happy with the new lighting. It provides increased illumination levels and a greater level of comfort and security that comes with the fixtures’ abilities to not only fight COVID-19, but also to reduce harmful germs and bacteria that can be found and spread in athletic-type facilities,” says Peter Volpe, UMass electrical engineer.

While the lights were installed prior to the pandemic, UMass has investigated using them not only in locker rooms and training facilities to disinfect, but also in public spaces, such as lobbies and waiting areas, where they would also be helpful in preventing the spread of COVID-19. Further, the university also gains the traditional benefits of transitioning away from the use of fluorescent lighting.

“These fixtures use LED technology, so they have a longer lifetime then the fluorescent lighting they replaced, which will help reduce maintenance costs,” says Volpe. “The new fixtures do an excellent job of lighting the room and providing higher illumination levels than the fluorescent light fixtures they replaced while using less energy.”

Author

Dr. Cliff Yahnke is the chief scientist and head of clinical affairs for Indigo-Clean and Kenall Manufacturing which creates lighting solutions for the healthcare, cleanroom/containment, food processing, transportation, high abuse, and correctional facility markets. Yahnke can be reached at cliff.yahnke@kenall.com.

Source URL: https://www.constructionspecifier.com/visible-light-technology/

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