TULSA, OK — When asked why they come to the Woodland Hills Mall — which some have rated as Oklahoma’s number one shopping mall — consumers will most likely cite size and diversity, shopping convenience, and the pleasant atmosphere.

The thousands who visit each day do not realize, however, that they are being treated to something innovative in a regional mall or other retailing center. It’s pure, fresh-smelling indoor air that is continuously cleansed by leading-edge technology ultraviolet (UVC) devices that have been finding their way into hospitals, pharmaceutical plants, food processing lines, and other sanitary-air environments.

The recently installed UVC Emitters™, manufactured by Steril-Aire Inc., Cerritos, CA, are part of a total renovation of the HVAC system that serves the mall’s common areas and 165 stores that combined occupy 1.1 million square feet of useable and leasable space.

“The rooftop air-handling units at Woodland Hills Mall were 20-26 years old and badly outmoded,” states John O. Saville, operations manager of the mall, which is co-owned by Rodamco N.A., Chicago, IL, and J.P. Morgan Chase & Co., New York, NY. “When we set out to replace them, our goals were to save energy, simplify maintenance, and deliver the best possible temperature, humidity, and air quality control to our tenants and shoppers.” The units would also have to operate efficiently under severe environmental conditions: Ambient rooftop temperature can rise well into the triple digits during the summer months.

“In designing the new units, we knew it would take lots of bells and whistles to meet our performance objectives, and standard off-the-shelf products did not measure up. We also recognized that air quality standards are become increasingly more strict, and we wanted to stay ahead of the curve,” Saville notes.

After reviewing three bids, he awarded the contract for 22 single-zone variable air volume (VAV) rooftop air handlers — 1,700 tons of equipment in all — to Octagon Air Systems, Conley, GA, a manufacturer specializing in custom HVAC systems for commercial, industrial and institutional use. “Octagon listened to our suggestions and was willing to go outside the normal design parameters to custom-build our air-handling units,” he adds.


Saville had learned of a new generation of UVC devices that are said to eliminate mold and mildew in HVAC systems and reduce the spread of cold and flu viruses and other airborne-transmitted diseases when applied properly. Working with manufacturer’s representative M/M Environmental Equipment Co., Oklahoma City, OK, Saville specified Steril-Aire’s specially made, multi-patented UVC Emitters for installation in the custom air handlers.

The UVC units are designed and manufactured to produce output significantly greater than conventional UVC tubes in cold and moving air so that they can actually be installed just downstream of a cooling coil, which also encompasses the drain pan and other damp locations. Here, the UVC energy cleanses the air and decontaminates the drain pan for improved IAQ. It also removes and prevents the formation of an organic biofilm that routinely builds up on the coil’s cooling surface — a condition which, along with drain pan buildup, produces odors and causes efficiency, maintenance, and operational headaches.

“With the old air handlers, our crews had to clean the evaporator coils annually and the condenser coils twice a year,” explains Saville. “We expect the UVC lights to significantly reduce or even eliminate these tasks and significantly minimize the maintenance staff’s exposure to a variety of chemicals. Also, it’s common knowledge that dirty coils experience an increase in pressure drop, which relates directly to higher energy consumption. So even though we specified UVC initially for its IAQ function, we expect it to deliver those all-important energy-saving and maintenance benefits as well.”

Coil surfaces and other system components, Saville notes, will also be protected by a “double filtering” system that filters both the outside air and the return air to remove the high levels of large particulate contaminants found locally.

The list of special features goes on and on. Saville explains, “Our units have digital controls and a vestibule so that a technician can walk inside the unit and troubleshoot it without having to enter the hot and noisy condensing section. There are oversized condensers to allow efficient operation in severe temperature conditions. The vestibules are conditioned to maintain a constant temperature and protect the electronic componentry.

“Fluorescent lights in every compartment also aid serviceability. There are windows with moving parts, so that a technician can view the unit without opening a door and depressurizing the ducts. The end result is unlike anything in a regional shopping center today.”

Todd Curlee, a partner at Octagon who was involved in every phase of the HVAC renovation, agrees. “These air-handling units have a special combination of features to achieve the owner’s goals of enhanced energy efficiency, air quality, serviceability, and operating control,” he claims. “What’s more, they are built to last 40 years, not the usual 15 to 20 years.” Curlee does not take credit for the innovations but attributes them to his client, whom he describes as “hands-on, knowledgeable about HVAC — and that rare breed of owner who regards long-term benefits and life-cycle costing as more important than just initial price.”


To minimize disruption of mall business, the new units had to be installed on an extremely tight timetable. “It’s Octagon’s practice to measure everything at the jobsite and build the new units to fit existing rooftop conditions,” Curlee explains. “On rigging day, we send a team of factory technicians to help the installing contractor lift the old unit off, put the new one in, and start up the same day.

“The original plan called for us to complete the installation of 22 units in 16 days,” continues Curlee. “We actually delivered the equipment before the original due date and were able to speed up the installation schedule as well. As a result, the renovation was completed five days ahead of plan, saving the mall thousands of dollars in crane rental and labor costs.” The 266 UVC Emitters were pre-installed at the Octagon factory, and the Emitter tubes were later installed at the jobsite to preclude breakage, he notes.


Though the air handlers have only been operating for a relatively short time, early results are very positive. In September 2001, for example, Saville reports 29% savings based on kilowatt usage compared to September 2000, a comparable month in terms of temperature and weather conditions. “The new air handlers are so quiet, it’s hard to tell they’re running,” states Saville. “Also, with the older units, we used to notice a moldy odor during early morning startups. That doesn’t happen anymore, because the UVC lights keep everything like new and free of mold and mildew.”

The UVC devices operate round-the-clock to maintain their germicidal and coil cleaning effectiveness, and the mall anticipates replacement of the Emitter tubes on an annual basis, after almost 9,000 hours of service. To ensure reliable operation, each air handler is equipped with a radiometer that monitors the UVC energy level and alerts technicians to any potential loss of output.


Will UVC-equipped air handlers with other state-of-the-art features become commonplace in the world of retailing? “Though the units we manufactured for Woodland Hills Mall are certainly unusual, I think we’ll see a trend toward this type of equipment in the near future,” predicts Octagon’s Curlee. “Property owners are starting to realize that higher quality mechanical equipment pays for itself in longer service life, reduced maintenance and downtime, and greater energy and operating efficiencies. UVC Emitters are an integral part of this strategy because, in keeping HVAC components free of mold and organic buildup, they help to achieve all of these benefits. Also, by creating a cleaner, fresher-smelling environment and preventing the spread of germs in retail spaces, UVC lights give mall owners a valuable marketing tool that can be used to attract tenants and shoppers along with giving them well-deserved peace of mind.”

For further information on UVC, contact Steril-Aire at 562-467-8484 or visit www.steril-aire-usa.com.

For further information on Octagon HVAC equipment, contact Octagon Air Systems at 404-608-8881 or visit www.octagonair.com.

Publication date: 11/11/2002