St. Luke’s Cataract & Laser Institute, which says it has performed more cataract surgeries than any other eye care clinic in the world, uses ultraviolet germicidal irradiation light systems for disinfecting its surgery rooms and promoting clean HVAC construction system coils for better indoor air quality.

So the Tarpon Springs, Florida-based eye care company didn’t blink when it recently paid to install UV surface disinfection equipment to supplement the daily manual sterilization of two operating rooms at its Villages, Florida, clinic — the newest of its seven central Florida offices. Contractor Trinity UVC Lighting LLC installed UV lamps in three rooftop HVAC systems to supply the 9,600-square-foot building with clean air, devoid of allergens, mold and any other biological contaminants.

“As far as I know, we’re one of the few — if not the only eye care surgery company — in Florida using UV disinfection to this degree,” said Donald Bislick, a facilities manager and information technology professional at St. Luke’s, which says it attracts patients from 77 countries worldwide.

The institute’s other two locations with operating rooms — its headquarters in Tarpon Springs and a 14,525-square-foot clinic in Clearwater, Florida, which also performs cosmetic surgery services — both have UV surface disinfection for operating rooms and HVAC coil disinfection. 

Sanitary conditions

Company officials say the efforts illustrate its commitment to providing sanitary environments for patients and employees during services that include comprehensive ophthalmology, cataract procedures, laser vision-correction surgery and treatments for vitreoretinal diseases, glaucoma and cornea conditions.

The Centers for Disease Control lists hospital-acquired infections as a major problem in the health care industry. St. Luke’s says its disinfection record is confirmed by an independent review from the Accreditation Association of Ambulatory Health Care in Skokie, Illinois.

St. Luke’s uses ultraviolet disinfection equipment providing UV-C wavelengths, which are most effective in eliminating microorganisms from surfaces and HVAC coils. UV “A” spectrum (used for black lights), UV-B (used in tanning salons and responsible for the darkening of skin exposed to the sun) and UV-C wavelengths are all present in sunlight. Higher frequency UV-C wavelengths are filtered by the Earth’s atmosphere, so microorganisms have no experience or defenses against it. UV-C light kills microbes by scrambling their DNA and preventing reproduction.

Trinity UVC Lighting, which has specified and installed commercial building and medical facility UV systems throughout Florida, specifies and installs 390-microwatt lamp systems manufactured by Fresh-Aire UV of Jupiter, Florida. The lamps are three times more powerful and require only three hours of nightly disinfection versus the health care industry’s standard 120-microwatt lamps requiring eight to 10 hours of operation. The shorter, but equally effective, disinfection time extends lamp life, saves energy and reduces maintenance costs. The patented Fresh-Aire UV power supply for each lamp carries a lifetime guarantee, company officials said.

Calculations

Ultraviolet surface disinfection system size and time exposure must be precisely calculated to ensure the organisms are killed. Brian Stacy, Trinity UVC Lighting’s vice president of sales, points to data from organizations such as the CDC to calculate the microwattage required to irradiate any known biological contaminant, such as clostridium difficile or methicillin-resistant staphylococcus aureus.

A calculation typically includes a room’s square feet, ceiling-to-floor distance, lamp output and a microorganism’s recommended microwattage irradiation requirement to arrive at an effective exposure time. Additional variables include room ventilation air changes, humidity, lamp-placement shadowing and the space’s allowable down time for disinfection.

Stacy’s calculations allow for the worst-case scenario and also specify a 200 percent protocol above recommendations because all UV lamps slowly lose intensity over their expected one-year lifespan. He also slightly oversizes a system to ensure even the most resilient microorganisms are irradiated, such as vegetative and spore-forming clostridium difficile, which can require UV dosages ranging from 11,000 to 46,000 microwatts in seconds per square centimeter.

“A static system such as this ensures the same disinfection time every day, whereas portable UV robots require qualified employees to program, position and monitor them properly during use for efficacy,” Stacy said.

The Villages clinic’s 900- and 1,200-square-foot eye surgery rooms each have four 32-inch-long, stainless steel, ceiling-mounted, ozone-free ultraviolet lamp fixtures positioned in the middle of the rooms. Timers activate the lamps for disinfection when the offices are closed. 

Monitoring

Since UV-C wavelengths can be harmful to eyes and skin, Trinity UVC Lighting has built in UV-monitoring entry-door sensors and motion-detection safety measures that can prevent accidental activation during times when staff or patients are present. Systems also allow manual operation by authorized personnel with timed shut-offs after the correct time for disinfection.

After the warranty period, the service contract calls for Trinity UVC Lighting to periodically inspect all the ultraviolet systems and perform lamp evaluations with radiometers.

“It’s important to keep systems operating with full intensity to ensure disinfection,” said Stacy.

Trinity UVC Lighting will soon install eight 32-inch and 46-inch UV-C lamps in the Villages location’s three York air handlers, manufactured by Norman, Oklahoma-based Johnson Controls. The air handlers in the surgery centers total 7,100 cfm and are supplied with chilled water from the Villages’ community central plant. Trinity UVC Lighting designs, custom builds and installs UV systems using Fresh-Aire UV power supplies, lamps and other components engineered specifically for disinfecting an HVAC construction system’s airstream, evaporator coil and interior surfaces.

The air handlers discharge air between 42°F to 47°F, and in-duct electric reheaters manufactured by Tutco Heating Solutions Group of Cookeville, Tennessee, are designed to raise the temperature to surgery room temperatures as per the American Society of Heating, Refrigerating and Air-Conditioning Engineers’ recommended standards.

St. Luke’s Tarpon Springs facility was its first to incorporate UV disinfection about 15 years ago. The three-story, 78,000-square-foot office building uses 40 UV lamps to disinfect the supply and return side of eight air-handler coils supplied by one 120-ton Trane chiller and 80-ton and 40-ton chillers manufactured by Carrier of Syracuse, New York.

Reduced maintenance

Before the lamps were installed, the Tarpon Springs facility needed semiannual HVAC market service calls to remove mold and slime on coils and the drain pans. Now the UV lamps prevent biological-contaminant growth inside the HVAC systems and ductwork, saving the facility approximately $8,000 per year that it once paid for coil maintenance, officials said.

In addition to better patient and employee health and IAQ, the clean coils also result in better heat transfer and energy efficiency. St. Luke’s no longer uses toxic cleaning chemicals that can create airborne contaminants, which can damage the environment, prematurely corrode the coils and shorten expensive HVAC unit life. 

The Tarpon Springs location’s initial 60-day UV system trial in one HVAC unit produced such impressive results that St. Luke’s administrator J. Bradley Houser approved UV systems for the building’s other seven HVAC systems.

“Their attention to detail and understanding of disinfection makes UV technology and how it works an easy sell,” Stacy said.

This article and its images were supplied by Fresh-Aire UV.