By Allan B. Colombo
From the April 2021 Issue
The need for a viable means of neutralizing bacteria and viruses is something that most facility management teams were likely less concerned about than after the novel coronavirus began to make its way from Wuhan, China to virtually every corner of the globe. At some point in 2020, it was obvious to facility managers that an effective means of disinfection was necessary on a facility-wide basis if office buildings, hospitals, grocery stores, clinics, and others were to reopen and remain so.
“Now more than ever, with this pandemic, companies around the globe are looking for ways to continue their operation, or reopen and to ensure that their employees or occupants stay healthy and safe in an environment designed with safety in mind,” says Joe Semaan, business leader, digital solutions Americas, with Signify of Somerset, NJ.
This is where germicidal UV comes into play. It adds an extra layer of disinfection beyond current protocols used by cleaning crews. Semaan says, “This is essentially an additional layer of protection that can help building occupants feel safer because UV-C is, in itself, a fast, effective way to deactivate harmful viruses on surfaces, in the air, and on objects.”
Bacterial and viral infections apparently can proliferate on surfaces as well as in the air, although there is conflicting consensus on this issue. But at the end of the day, facility managers must assume that both premises have merit and act accordingly. Whether surface, airborne, or both, the existence of a dangerous pathogen in any environment is a threat to public health.
One option, the prevailing focus of this article, is the utilization of Ultraviolet (UV) lighting. There are three types: UV-A (315 to 400 nm), UV-B (280 to 315 nm), and UV-C (100 to 280 nm). Each represents a range of the Electromagnetic (EM) spectrum within the UV band, measured in nanometers (nm).
“Exposure to high-intensity germicidal UV light for a specific amount of time creates a situation where pathogens are rendered inert so they can no longer replicate,” says James Rosborough, regional sales manager, eastern U.S., with Armstrong Ceilings of Lancaster, PA. “So it’s different than filtering. When you filter, you catch those viruses and they remain intact in a HEPA or MERV filter. With UV light, it truly does neutralize them.”
For the purpose of disinfection of surface and airborne bacteria and viral infections, our primary interest within the purview of this article will center on UV-C.
When it comes to germicidal disinfection using UV-C, there are three ways to treat a space. These include: HVAC Air-Stream; Upper Room Air; and Direct Surface. Of note about the first and second options is that the rooms in which these two disinfection methods are employed can remain open and in use during disinfection. The third method—Direct Surface—requires that the room be void of humans and animals. This is because the wavelengths employed in UV-C lighting, in combination with the higher intensity of the light source, have the capacity to overradiate and damage the skin.
When using the HVAC Air-Stream method, UV-C lamps are installed inside of HVAC units. They can be installed within air plenums, air ducts, in air-distribution systems, and multiples of all three. The positive aspect associated with this method is that it helps prevent and control the growth of pathogens within the HVAC system itself, in addition to room air that people breathe.
The Upper Room Air distribution method involves the neutralization of pathogens within the air over the heads of the occupants in the room without disturbing them. This can be carried out in three ways: Closed Air Handlers; Ceiling-Level Room Air Disinfection; and Room Surface Disinfection. In all cases, the “dose” necessary to kill microbes is determined by the intensity of the UV-C employed, the manner in which UV-C is applied, the amount of time allowed for exposure, and the specific pathogen(s) involved.
Closed Air Handler Disinfection
As mentioned earlier, under normal conditions, the potential of injury exists when someone is directly exposed to 100 to 280 nm (UV-C) for a length of time. According to Rosborough, “Exposure to humans with UV-C light is very bad; it can give you one heck of a suntan very quickly. It’s been used for decades in hospitals and other medical settings to clean surfaces and equipment, because it’s an effective means of disinfecting.”
One type of UV-C disinfection system offered by Armstrong Ceilings—the VIDASHIELD UV24—sits in a 2 ft x 4 ft space in a suspended ceiling grid. This particular unit can be ordered with standard florescent lamps for room-side illumination, like any standard fluorescent light fixture. It’s what’s above ceiling that purifies the air while protecting people from its potentially harmful UV-C light rays.
Rosborough explains that this unit features a series of fans that draw air into a sealed chamber from the space below. A highly-reflective spectral material in the chamber provides even distribution of UV-C light. The air is drawn through this chamber and expelled back to the space after it’s been purified.
Wall-mounted UV-C purification systems are also common, providing UV-C air purification at ceiling level. Like the Armstrong Ceilings unit, these often contain a MERV filter designed to remove larger particulates before they enter the inner chamber where the UV-C light bulb(s) are located. Some units also contain a HEPA filter.
All of these UV-C systems focus on air in the room, not the surfaces directly, but because germs are largely neutralized, the surfaces should realize a noticeable reduction in active pathogens. In all cases, air is drawn into a closed system, treated with UV-C and, released back into the environment.
Ceiling-Level Room Air Disinfection
This method hinges on wall-mount UV-C strips designed to illuminate the ceiling with a germ-neutralizing light in the UV spectrum. Louvers in the front of each unit where UV-C light exits are angled upward at a specific angle so the light cannot reach occupants below. In other words, people can work, play and socialize in the room without ever knowing that above their heads the air is being purified.
“We have a product that is called our ‘Indirect Upper Air Fixture’ that continuously disinfects the air. This is a light source, this is a fixture that’s installed and angled upwards at a certain height [on the wall] at a given distance from the ceiling above people’s heads,” says Signify’s Semaan. Signify’s published specifications call for a minimum of 8 ft. 3 in. from floor to the bottom of the UV-C fixture with a minimum of 9 inches from the top of the fixture to the ceiling with at least 20 feet of space to the nearest wall or obstruction.
Keep in mind that every situation is different, and so it may be necessary to obtain the assistance of a UV-C professional when sizing up and engineering a system.
Like the self-contained Armstrong Ceiling’s AHU, discussed in the previous section, this one bathes the air above with UV-C, neutralizing bacteria, viruses, fungi, and other pathogens. Semaan says that as air circulates in the room, it becomes more disinfected.
Room Surface Disinfection
A room surface disinfection system is designed to effectively neutralize surface pathogens. Here, rooms are treated with UV-C light emitted by ceiling-mounted fixtures.
“The second piece [in our UV-C treatment program] is what I’d call Direct UVC illuminators that disinfect surfaces. Typically those tend to be ceiling mounted UV-C lamp fixture combinations. They can be controlled automatically to disinfect areas outside of business operating hours, or when people are not present in the space,” says Signify’s Semaan.
Typically if you’re familiar with what a troffer looks like, or what a strip looks like, or a hybrid, these are your official types of luminaires that have been outfitted and specifically designed with UV-C lamps, like the LightFIGHT UV-C lamps manufactured by LEDVANCE LLC of Wilmington, MA.
LEDVANCE also manufactures ballasts designed to interface with an occupancy sensor. This ensures when they do come on, there are no people in the space, absolutely critical when using dynamic scheduling that turns them on at a specific time.
Glen Gracia, head of communications at LEDVANCE, explains, “Our LightFIGHT UV-C Programmed Start Ballasts are ideal for applications where the motion sensor turns lights off and on frequently. Programmed start ballasts use a precise starting sequence to minimize loss of emissive material to prolong lamp life, while providing the efficiencies expected from a T8 electronic system and reducing maintenance costs. Our LightFIGHT UV-C lamps and ballasts are specifically paired to deliver the correct radiant output power to meet the design guidelines to inactivate microbes.”
Finally, developments in lighting overall have made an impact on the potential of UV lighting that facility executives are seeing.
“Today, LED products that more effectively deliver low UV doses (compared to traditional light sources like mercury lamps) are making direct UV disinfection more practical in occupied spaces,” says Tom Boyle, CTO of GE Current, a Daintree company. In describing that company’s offering, Boyle explains, “The 365DisInFx™ LPU is the first UL-Certified direct LED UVC luminaire for continuous operation in occupied spaces.”
The need for a safe, effective way to neutralize pathogens in commercial settings has never been as important as it is today. With increased requirements by local and state health departments that directly relate to COVID-19, it makes business sense to consider UV-C purification for your facilities.
Colombo is a long-time trade journalist and professional in the buildings industry. He is factory trained by prominent manufacturers in plumbing, heating/cooling, and electrical, and he’s a recipient of the prestigious Jesse H. Neal Award. A longtime trade journalist in the security and life safety markets, Colombo worked for McGraw-Hill Education, and his articles have appeared in numerous magazines.
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