GRAND RAPIDS, Mich. - A mechanical inspector's tools of the trade include codebooks and a great deal of knowledge and experience. Every so often, a refresher course on new mechanical equipment and systems is essential. That's where John Reilly comes in.

Reilly is the western Michigan district sales manager for Research Products Corp. He conducted a seminar on indoor air quality (IAQ) for members of the Mechanical Inspectors Association of Michigan (MIAM) at the group's fall conference in Grand Rapids in early September. The topic was "Indoor Air Quality, UV Lamps, Filtration." He told inspectors that he wanted to give them a "sense of indoor air quality and why it has become so important."

Why Filtration?

Reilly said the most basic reason for filtration is to protect mechanical equipment. Beyond that, he said filtration is useful for protecting humans from particulates.

He said that initial American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) standards used for determining varying levels of filtration were confusing, so ASHRAE eventually developed the minimum efficiency reporting value (MERV) standard to test filter effectiveness on particles of various sizes. The MERV standard cuts down on the confusion, according to Reilly.

"If I can identify a particle and its size, then I know what filter to look for based on its MERV rating," he said.

He noted there are three interrelated aspects of all media filters: efficiency, surface area, and resistance. "They all work together," Reilly said. He added that people "should be aware of the resistance factor, since high resistance could be starving a system for air."

Reilly also talked about "electrically charged" air filters, which have an initial high-efficiency rating. But as they load up with charged particles, efficiency drops off as particles begin to act as insulators. "Efficiency remains high with charged filters as long as people perform the required maintenance as recommended by installers," he stated.

Ultraviolet Lights

Reilly pointed out that although ultraviolet (UV) lighting has been around a long time, its widespread use in the HVACR trade has occurred mainly in the last 10 years. He described several different examples of UV lighting, but stated the most common applications in the HVACR trade use UV light in the C-band of the spectrum (UVC).

"One of features of UVC is its high intensity," Reilly continued. "It can help stop colonization of mold and prevent its growth."

He used the example of mold growth on "A" coils because of the environment - often dark and moist - can be a breeding ground for mold growth.

"If you expose the coil to UVC light, you will eventually kill all of the mold, and keep the drain pan clean," Reilly said. "Keeping the coil clean will increase equipment efficiency, up to the SEER rating of the equipment."

He noted that positioning of UV lighting is important, especially around plastic materials, which may degrade under the UV rays. "But when UV lighting is properly applied, it really works well," Reilly said.

The Power Of Ventilation

Reilly also spent a few moments explaining the importance of proper ventilation to MIAM members. "Most states don't have ventilation codes when it comes to residential applications," he said.

Reilly pointed out that homes are becoming more energy efficient, but the progress is often offset by the introduction of harmful gases emanating from products like carpeting and furniture.

"If you put a lot of these products into a new home, it is almost impossible to vent out the gases," he stated.

He said the problem is compounded during periods with mild outdoor temperatures, when mechanical equipment is not running and ventilation is reduced.

He pointed to one solution - Aprilaire Ventilation Control System - which allows for customizing the time the damper is open and the blower is running, thus meeting ventilation requirements of any size home.

Publication date: 09/27/2004