From schools and shopping malls to archives and federal buildings, indoor air quality (IAQ) systems are becoming more sophisticated and widely applied. In particular, UV lights and specialty filters are finding more diverse applications.

In public-use facilities, IAQ systems help reduce indoor contaminants that can create discomfort and a poor indoor environment. In archival facilities, they help maintain a stable atmosphere that is critical for long-term storage. In all applications, properly designed, installed, and maintained IAQ systems extend the longevity of the HVAC system with which they function.

The UV light was installed in a wall-mount HVAC unit.

Case One: Capistrano Unified School District

Facilities staff for the Capistrano Unified School District in Southern California felt they had done everything they could to keep classroom air clean for students and teachers. HVAC systems were regularly maintained and classrooms were regularly vacuumed. Doors and windows stayed closed to keep out pollutants. But the air still held mold spores and pollen, which could set off students’ asthma attacks and allergies.

Capistrano administrators and facilities staff decided to try something new. They tested an ultraviolet (UV) air purification unit in a sixth-grade classroom. The Sanuvox unit was installed in a Bard wall-mount HVAC unit without any extrusions.

At first, there were no noticeable changes in the classroom environment—no new noises, smells, and no contraption in the corner of the classroom, which could have drawn off the students’ attention. “You can’t see it work, you can’t hear it, and you can’t smell it,” said Layne Miller, vice president of Geary Pacific Supply. “When it’s done its job, you can’t see that there’s any difference.

“What we find is there are believers and nonbelievers,” Miller continued. “They either understand how it works and it makes sense to them right away, or they think it’s smoke-and-mirror kind of stuff.”

When properly located, UV lights can help keep A/C coils clean.

Verified Results

The difference in the room was not immediately noticeable. In order to determine whether or not to install more of the purification units, the school district’s officials hired an independent laboratory to check the unit’s progress. The air was tested before the unit was installed and then again one month later.

After four weeks, the improvement in the classroom’s air quality was dramatic. Fungal elements and skin cell fragments were reduced by two-thirds, and pollen numbers were cut in half. The unit’s proprietary UV process had cleaned the air quickly and thoroughly.

Capistrano school officials have noticed additional benefits. In the past, the schools’ cleaning regime included vacuuming as much as possible, cleaning and dusting, and changing filters in HVAC units. Indeed, their cleaning/maintenance routine is common in schools around the country. Sanuvox says its UV unit picks up where vacuuming, HVAC maintenance, and fresh-air ventilation leaves off.

As the classroom air flows through the unit, it is pushed past two high-powered UV lights and two parabolic reflectors. The manufacturer explained “that light eliminates contaminants in the air, such as mold spores, bacteria, mildew, formaldehyde, solvents, and viruses.” The clean air is returned to the classroom environment.

“It will eliminate any and all of those contaminants on an ongoing basis and maintain the purity of the air that the kids are breathing in the classroom,” Miller said. “Every 15 to 20 minutes, the air in that classroom will be purified, resulting in a major improvement over previous indoor conditions.”

Cleaner air means fewer allergy attacks, less sickness, and fewer absences. It also means less maintenance on the HVAC unit and additional energy savings, because the UV light keeps the coil clean, the manufacturer explains.

For more information, call 888-726-8869 or visit

Case Two: UVC Lights In The Mall

When people are asked why they come to the Woodland Hills Mall (a shopping mall located in Tulsa, Okla.), they most often cite size, diversity, shopping convenience — and the pleasant atmosphere. The thousands who visit each day don’t realize that they are being treated to indoor air that is continuously cleansed by ultraviolet C-band (UVC) devices that have been more commonly installed at hospitals, pharmaceutical plants, food processing lines, and other sanitary-air environments.

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

“The rooftop air-handling units were 20 to 26 years old and badly outmoded,” said John O. Saville, operations manager of the mall, which is co-owned by Rodamco N.A. (Chicago) and J.P. Morgan Chase & Co. (New York).

“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,” Saville added. 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,” Saville continued. “We also recognized that air quality standards have become increasingly more strict, and we wanted to stay ahead of the curve.”

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.

Woodland Hills Mall’s new air-handling units have state-of-the-art controls and IAQ features such as UVC emitters, said John O. Saville, operations manager of the mall.

Reduced Chemical Use

During his research, Saville had learned of a new generation of UVC devices which, when applied properly, are said to eliminate mold and mildew in HVAC systems and reduce the spread of cold and flu viruses and other airborne-transmitted diseases. Working with manufacturer’s representative M/M Environmental Equipment Co. (Oklahoma City), Saville specified the UVC Emitters for installation in the custom air handlers.

According to the manufacturer, the emitters are designed to produce so much UVC output in cold, moving air, they can be installed just downstream of a cooling coil, which also encompasses the drain pan and other damp locations. Here, the UVC can cleanse the air and decontaminate the drain pan. It also can remove and prevent the formation of an organic primed biofilm that routinely builds up on the coil’s entire cooling surface — a condition which, along with drain pan buildup, produces odors and causes efficiency, maintenance, and operational headaches, the manufacturer points out.

“With the old air handlers, our crews had to clean the evaporator coils annually and the condenser coils twice a year,” explained 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,” he concluded.

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

Service Features

Saville continued: “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,” Saville concluded.

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 claimed. “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.”

Ahead Of Schedule

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 explained. “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,” continued 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.”

The 266 UVC Emitters were preinstalled at the Octagon factory. The tubes were installed later at the jobsite to prevent breakage.

The results to date are very encouraging. In September 2001, for example, Saville reports 29 percent 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,” stated Saville. “Also, with the older units, we used to notice a moldy odor during early morning startups. That doesn’t happen anymore.” He attributes the change to the use of the UVC lights.

The devices operate round-the-clock. Replacement of the emitter tubes takes place after almost 9,000 hours of service. Each air handler is equipped with a radiometer that monitors the UVC energy level and alerts technicians to any potential loss of output.

UVC Trend?

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,” predicted 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.”

For further information, contact Steril-Aire, Inc., at 562-467-8484, or visit; and contact Octagon Air Systems at 404-608-8881, or visit

Case Three: National Archives Of Australia

The Victorian branch of the National Archives of Australia hired Purafil, Inc., Doraville, Ga., to protect its documents and artifacts from gaseous contaminants that cause decay and discoloration.

Located on a main urban road, the archives is the public records office for the local Victorian government and is also the federal government’s official repository for all Commonwealth records dating back to 1901.

The archives house Aboriginal Affairs records, World War I and World War II defense correspondence, internee files from World War II, dossiers of servicemen from the Boer War, and other important pieces documenting the country’s heritage.

Built in 2000, the archives is a pristine, airtight facility with highly controlled temperatures to protect the artifacts. Engineers working with the archives specifically selected special filtration systems to maintain the cleanliness of the environment.

More than 20 air-handling units were custom built in the mechanical room to eliminate gaseous contaminants from the outside air intake. The units included 50-percent ASHRAE-grade prefilters and 220 Purafil filtration systems.

Gas Transformation

Each of the 220 filters contains CP Blend® dry-scrubbing media to eliminate a wide range of gases by transforming them into harmless solids, the company says. The filter’s V-shape design is said to improve contaminant removal efficiency by lowering velocity within the media bed and increasing the surface area.

The low pressure drop and high surface area of the bed increases contact time with gaseous contaminants, which results in efficient contaminant removal and minimized energy costs, the manufacturer states.

Purafil’s OnGuard® continuous corrosion transmitter (CCT) monitors were also installed in the archives to measure the amount of reactivity in the environment in real time.

According to room classifications for museums and archives, 90 Angstroms of buildup is a sound result; the CCTs in the Archives recorded just 10 Angstroms.

Indoor conditions at the archives can be controlled with “immeasurable fluctuations in temperature and humidity,” according to Purafil.

For more information, contact Purafil Inc. at 770-662-8545, or visit

Publication date: 03/17/2003