Two of the most common sources for poor IAQ are mold and bacteria and Jon Zickermann knew he had a problem with both. As the director of maintenance and operations at the Mequon-Thiensville School District in Wisconsin, he had the responsibility to protect the health and quality of life for students and faculty in six separate schools. That included controlling airborne microbes that create odor and cause disease.

“You’re always doing anything you can to control contamination of any kind,” said Zickermann. “For instance, for a long time we would do a weekly disinfectant rub down of the equipment in the high school weight room in an effort to control the MRSA [Methicillin-resistant Staphylococcus aureus] bacteria. But we had no idea of how effective it was or what percentage of bacteria we were killing. Then again, none of our kids got infected.”

Despite other health risks, the main foes Zickermann focused on protecting his charges from were mold and bacteria.

MOLD ENCOUNTERS

Everyone has encountered mold in moist environments in their homes. Naturally, it also exists in larger buildings, including schools. Mold spores are always present in the air, and a single spore contains all the DNA necessary to start a colony. All it needs is moisture and a little nutrition. Coils in air handlers provide an ideal environment for mold because they are dark, damp, and provide the nutrients on which mold thrives. Environments such as bathrooms and locker rooms are ideal breeding grounds as well. Once mold establishes itself in a coil or drip pan, it provides an ideal place for bacteria to grow. It also creates other toxins of its own. All of these enter the airstream and can threaten the health of building occupants.

According to the World Health Organization (WHO), more than 60 percent of IAQ problems and allergies may be related to mold contamination. Prominent IAQ diagnosticians put the percentage as high as 80.

“In almost any climate an air conditioning unit has the capacity to condense moisture from the air,” said Mike Perinovic, owner of Filtration Concepts, a Wisconsin-based distributor that is tightly focused on IAQ solutions. “Whether the air has been artificially humidified, as is done in arid climates, or the air that has been dehumidified from the cooling process, as is found in humid regions, there is more than enough moisture to support the growth of microbial contamination.”

FINDING ALL SOURCES

Zickermann thought his mold and bacterial problems began in the locker room. “The football locker room had been an ongoing odor problem for years,” he said. “You know teenagers; they come in from practice with their practice uniforms soaked with sweat and rain and stuff them in their lockers and never wash them. It’s a perfect breeding ground for odors. But we could never find a solution until Nick stopped by.”

Nick Orlando is a representative for Filtration Concepts and had come to Zickermann’s office to discuss filter options.

“The topic soon changed to his locker room problem,” Orlando recalled. “He asked if I had any kind of a solution, and I told him I thought I did, but it would have to be handled at both ends of the problem: the locker room and the main source of the contamination, the air handler.”

DETERMINING INTENSITY

Orlando proposed a solution making use of two different arrays of ultraviolet (UV) light. The first was to address the source of much of the mold contamination: the coils of the air handler. “We proposed using lower intensity UV lights in the C band which is the most efficient for killing mold and bacteria,” said Orlando. “The manufacturer we represent, Ultraviolet Devices Inc., uses a formula to determine the correct combination of intensity and time of exposure.”

The lamps, UVDI’s Altru-V series, were positioned to cover the outer surfaces of the coil.

“Some people claim that UV light only kills what it can see,” said Orlando. “And that’s true as far as it goes. What they forget is that UV light reflects off of surfaces just as daylight does. So, as they kill the mold on the outer surface, it falls off revealing the surface of the coil and the UV light reflects deeper into the coil, quickly killing all of the mold and bacteria.”

“It worked great,” said Zickermann. “The coils were soon shiny clean, and we no longer needed to schedule periodic hand cleanings. It’s like I have a technician up there scrubbing the coil 24/7.”

PROBLEM SOLVED

With the success combating mold, mildew, and bacteria in the coils of the a/c systems by using UV light, Zickermann and Orlando turned their attention to face the locker room challenge. “UVDI had just introduced a new portable UV system designed to decontaminate surfaces in rooms,” said Orlando. “The company calls it the Mobile Room Sanitizer and it’s designed specifically to kill bacteria and other airborne health threats in facilities where a lot of people gather together.”

The system is an array of vertical UV bulbs on a stand with casters. It can be placed in a room and will decontaminate all visible surfaces in less than an hour. While UV can only kill what it sees, it also reflects off surfaces in the room so that it decontaminates the entire room. The Mobile Room Sanitizer is equipped with infrared sensors to detect movement. Since UV rays are dangerous to humans, when movement is detected, the system shuts down and stays shut down until it is reactivated.

“In the case of Homestead High’s locker room, the locker doors were wire screen, so the light could penetrate and the system was moved four times to ensure full coverage,” said Orlando. “It worked great. We had planned to do three passes, but the first one killed 90 percent of the mold.”

“The odor disappeared after the first pass,” said Zickermann. “We were so pleased we ordered another unit. In the past when there was an outbreak of flu or cold bacteria, we would send maintenance workers in to wipe down classroom surfaces with disinfectant. Outbreaks don’t happen often, and, like the weight room, we didn’t know how effective our actions were. Now, with these UV units, we can have our second shift cleaning crews place them in a classroom and activate them to disinfect the entire room while they clean another. It’s a proactive way to prevent disease. We plan to get two more units for each of our seven buildings and use them as part of our regular cleaning routine.

“It’s funny that we initially started this to get rid of odor in a locker room and ended up improving the IAQ for the entire school district.”

Publication date: 10/11/2010