Rocco Nardi, service technician with the J.A. Marble Co. (Dearborn, Mich.), examines the filters from a rooftop unit on a high school building in suburban Detroit. (Photo by John R. Hall.)

On June 9, 2004, The Grand Rapids Press published a story about a proposed $165 million tax increase plan to refurbish school buildings in the local school district. The story detailed crumbling school buildings - many built in the 1920s - with ventilation systems that did not work. Sadly, the citizens of Grand Rapids, Mich., are not the only ones grappling with the problems posed by aging school buildings. Similar scenarios play out time and time again in school districts across the United States. Finding the funding to correct the problems is a matter for local school boards and taxpayers to decide.

Correcting the problems is the domain of those in the HVACR trade. With a growing number of aging school buildings, there has never been a greater need for HVACR professionals to step forward to help ensure that schoolchildren and teachers learn and work in safe and comfortable indoor environments.

Filtration equipment manufacturers are addressing the problem of ensuring clean and healthy air in institutional settings, and offering solutions that HVACR contractors can implement when designing and installing mechanical equipment in school buildings.

Filter options have changed to allow older units to upgrade filter efficiencies without sacrificing airflow. The filter configuration shown above offers as much as four times the media area offered in the same filter configuration five years ago. (Photo courtesy of Camfil Farr.)

Identifying The Problem

"You can imagine the type of equipment in most schools - installed by the lowest bidder, a lot of package terminal air conditioners (PTACs) or some form of through-the-wall fancoil units.

"These systems supply an overcrowded, under-filtered, and under-ventilated room full of students. To compound the situation, we usually run these rooms for nine months and then vacate the facility for three months, either turning down or off the HVAC system."

Compounding the IAQ problem, said Veeck, is the activity of smaller germs and microorganisms, which can spread exponentially. "One of the biggest culprits in this scenario is the lowly particles - aerosol contaminants - that are released from each and every individual at a rate of more or less one million particles per minute, depending if you are in the gymnasium or the library," he said.

He noted that particles consisting of bacteria, fungi, or viruses, piggybacked on moisture particles, called droplet nuclei, "combine together to create an atmosphere so dense that it can literally be seen with the naked eye."

"Billions of them cause each student's body to work harder to rid the lungs of these invading contaminants," he continued. "This ‘phagocytosis' causes the building occupant to cough, spreading even more droplet nuclei beyond what is spread naturally by sneezing.

"In other words, when the HVAC system's filters don't re-move the particulate, the building occupant's lungs do. And the really nice part is that the school system doesn't have to pay for this system like they have to pay for the HVAC system filters.

"Then there's that carbon dioxide level that should be somewhere around 1,000 parts per million (ppm) that tends to move upward towards 2,000, 3,000, even 4,000-plus in the classroom setting."

Veeck said that experts' ideas differ on proper levels of CO2, and nature seems to have it pretty well pegged outdoors at around 350 to 450 ppm.

"Reason tells us that this is the correct level and two times that may not cause problems," he said. "The question is, where is the best level to maintain good ventilation in the lungs of people in the building considering that each person is expiring carbon dioxide with every breath?

"Proper ventilation with cleaned, filtered outdoor air is the most efficient way to reduce CO2 levels, but the school system knows you have to spend money for gas-phase filters and to condition that outdoor air and you don't have to spend so much if you just recirculate it."

Schools do pay a heavy price for not doing good particulate and gas-phase filtration, stated Veeck. "Beyond providing an environment that is not conducive to learning, the sickness absenteeism rate costs the schools about $33.88 per student per day. By spending a few more dollars on higher MERV and gas-phase filtration and re-moving particulate and gas-phase contaminants, the schools could reduce absenteeism. For example, a 1 percent reduction in absenteeism would not only fund this increased filtration, but the school could realize several thousands of dollars more per year."

With today’s product technology, virtually any system may be upgraded to address air quality problems. In the photo above, low-efficiency panel filters were replaced with low-pressure-drop pleated panel filters. (Photo courtesy of Camfil Farr.)

Finding Solutions

"Over the last few years, we have noted some newly constructed schools and some renovated schools applying central system design. In these facilities, two-stage filtration of MERV 7 with MERV 13 final filters were installed, similar to a common office building.

"Over the last 30 years, through-the-wall package units have been the system of choice based upon lower installation costs, individual room control benefits, and a perceived ease of service."

He noted that the installation of a central system averages about 50 percent higher for installation, but asserted the overall life-cycle costs of the system are much lower.

"Today's central systems also allow economical individual room comfort control options," said Seyffer. "The most important factor is that IAQ can be addressed from the perspective that the equipment is designed to use higher efficiency filtration and introduce proper levels of ‘fresh' dilution air for removal of contaminants."

Katina Hejl, marketing specialist for Purolator Air Filtration, Henderson, N.C., said, "School IAQ problems are the same as those faced by other state-supported institutions; usually they are direct results of ever increasing budget cuts. Our economy today forces many school administrators to make the tough decision between clean air to breathe and healthy meals for the students. IAQ is not the only danger children face in public school, but it can be just as life threatening as gang violence or drug abuse."

Hejl noted that the EPA made a bold statement in 2002 regarding residential IAQ. "In some cases, the levels of air pollution inside of a home can be two to five times higher (and occasionally 100 times higher) than outdoor levels," she said.

"Understandably, we are concerned when we turn our attention to the IAQ levels in our public schools. At the very least, the HVAC unit in each school could be verified that it is clean and in good working order (the whole system, ducts, etc., not just the motor). Then, the maintenance technician at the school could schedule regular filter changes."

She emphasized that determining the right schedule for filter changes is essential.

"With normal residential use, it is recommended that an air filter in your home is changed every 30 to 90 days. Each homeowner determines what is the right schedule for filter changeouts for their IAQ, whether it is every 35 days or every 62. The same principle applies to school buildings; once the HVAC unit is in good working order, regular air filter replacement could make a world of difference in the end."

Doug Render, product manager for StrionAir, Louisville, Colo., said, "Schools present special problems for managing IAQ. Students and teachers often work more closely together in classrooms than people in office buildings; occupancy rates are higher than in alternative-use facilities; schools have diverse activities and a wide range of potential air pollutant sources including cafeterias, art and science classrooms, vocational education areas, pools, and locker rooms."

Render pointed out that some states are considering legislation that would address school air quality. Florida is considering a bill that would require each school district to take on an IAQ management plan, inspections, and evaluations.

In New Hampshire, a proposed bill would mandate that the state's department of education develop and implement IAQ standards for public and elementary schools. In Pennsylvania, a committee is currently discussing a bill that would set minimum IAQ and ventilation standards for all workplaces.

"Providing improved air filtration would be a great first step," he said.

Joe Muchow, president of the E.L. Foust Co. Inc., Elmhurst, Ill., stressed the need for educating school district officials on the importance of proper building design and maintenance procedures.

"The place to start to improve this situation is usually in the design, construction, and maintenance of the school buildings," he said. "School districts need to be better in-formed about the design of new buildings or when they are remodeling. I would definitely recommend that all school districts form an IAQ committee made up of school administration, maintenance staff, local teachers, and PTA or parents' organization. It might even be beneficial to include a Student Council representative in the higher grade levels.

"Good (and educated) maintenance of the HVAC system is a must. I have personally seen schools where the running school buses park right next to where the indoor air make-up vents are located for the building. One school I visited was built next to a garbage landfill. Site selection is important."

Muchow added that the use of pesticides, herbicides, and dangerous cleaning supplies should be limited or completely banned. "There are alternative products to eliminate these polluters," he said.

"New carpeting, painting, and remodeling should be done with a minimum use of chemicals, solvent-based products, or other contributors to poor IAQ.

"Many common-sense solutions can be made at the local level, without it costing the schools more money. School districts just need to get more educated about the size of the problem, and committed to the solutions. There is plenty of information about safe, ‘eco,' and green building technology available now, and there may even be government grant money available, too."

Medium-efficiency filters from Camfil Farr.

Sidebar: Manufacturers Offer Improved Filtration For Schools

"In educational facilities, you may find our filters used in HVAC systems from through-the-wall package units to fume hoods in laboratories. The most commonly used products are our pleated filters, although we would love to see educational facilities (K thru 12 especially) move their air quality related equipment to at least the same level we now apply in the most common office environments, typically a central service HVAC system."

"Our filters are an ancillary item to the existing HVAC system equipment. Our products exist in a wide variety of configurations to address particulate contamination from large paper dust particles common to school environments, to the maladies of infectious organisms that can be common when so many humans occupy close quarters. Filters are also available for control of gaseous contaminants, from standing school bus fumes to odors created from cafeteria, gymnasium locker rooms, and biology laboratories.

"Ironically, we install many costly retrofits for these odoriferous areas when they should have been addressed, or considered, with proper design during initial building construction."

A replacement filter from Purolator.

"Simply put, our products are air filters, which feature different types of media enclosed by various types of frames. In the furnace or forced-air system, air is forced through the media, which removes certain impurities in circulated air.

"With the correct filter and HVAC system in place, the usage of air filters will dramatically reduce airborne contaminants. Irritants such as pollen, dust, mold, pet dander, and even some bacteria (depending on the filter used) can be removed from the air, thereby increasing overall IAQ."

Six StrionAir GC Systems, with an expanded view of the disposable filter media.

"Our products feature high filtration efficiency, over 90 percent against submicron-sized particles; MERV 15 per ASHRAE 52.2-1999. A 95 percent bag filter will leave up to eight times more respirable particles in the air than a StrionAir system and a 30 percent filter, which will leave up to 12 times more respirable particles in the air than a StrionAir system. Only HEPA provides a higher level of filtration

"Products also have an active germicidal effect. Independent third-party labs have proven a kill rate of greater than 99.99 percent against a number of airborne pathogens that can cause respiratory illness. This improves health and safety by removing and killing harmful pathogens, safe filter removal and disposal, and greater effectiveness, all in a single, integrated unit.

"Finally, the products represent sound economics. They can be easily retrofitted into most existing air handlers without modifications to blowers, etc. They include a low pressure drop and actually reduces energy consumption versus bag or cartridge filters."

E.L. Foust Co. Inc. (www.foustco.com) manufactures "high quality air purification units that are used in many schools throughout the country," noted Joe Muchow, president of the E.L. Foust Co. Inc., Elmhurst, Ill. "In fact, Hawaii uses these machines in many of the classrooms there. Our Series 400 unit and our 160R2 are very popular for this use.

"These machines are very rugged; feature all-metal construction and powerful motors; have large carbon beds for control of fumes, odors, and gases; have state of the art HEPAs for particulate control; and optional UV lights for virus and bacteria control.

"Our machines do not produce ozone or ions. We use only proven technology that can be used in places inhabited by people. By using our machines and other products, the schools should have a healthier and safer environment for children, teachers, and all other staff. While I have no data, I suspect there is less absenteeism in these schools due to the better air quality. There are articles almost weekly about asthma and allergies in city schoolrooms around the country affecting the ability to teach and learn.

"We have independent laboratory tests to show the efficiency of the purifiers available also. These test results would be very helpful to HVAC contractors, IAQ committees, and maintenance staff at the schools."

- John R. Hall

Publication date: 07/26/2004