School Ventilation, IAQ, and Energy Loss
Studies Show Many Students Not Receiving Enough Fresh Air
Most adults can recall sitting in class in high school, struggling to stay awake, yawning nonstop, and chalking it up to lack of sleep, hormones, or an especially boring lecture. But, more than likely, our younger selves were suffering the very real side effects of poor IAQ, including temperatures outside the range of comfort, higher-than-recommended levels of carbon dioxide, and high humidity.
Though ASHRAE recommends bringing in 15 cfm of outside air per occupant in a commercial building, a growing number of studies show that many U.S. schools are falling significantly short of that goal, which can translate to lower test scores, increased absences, and other health issues caused by poor IAQ.
The solution, of course, is to bring more outside air into the schools, but doing so often comes with a hefty price tag due to the amount of energy required to condition the air. Luckily, there are ventilation solutions for schools that help mitigate energy loss and bring much-needed fresh air into the buildings.
IAQ in Schools
The exact state of schools’ IAQ across the U.S is not well understood, which is why the Center for Green Schools at the U.S. Green Building Council (USGBC) is calling for a new Government Accountability Office (GAO) survey on the state of schools in the U.S. But, based on available data from several smaller-scale studies, IAQ is one area where America’s schools are rarely achieving a passing grade.
A 2010 study of 100 classrooms in the Southwest, conducted by Dr. Richard Shaughnessy, manager of the indoor air program, University of Tulsa, showed that 87 of the classrooms had ventilation rates below recommended guidelines based on ASHRAE Standard 62 as of 2004. The study indicated that “increasing the ventilation rates toward recommended guideline ventilation rates in classrooms should translate into improved academic achievement of students.”
Similarly, a 2012 experiment conducted by researchers at the Lawrence Berkeley National Laboratory tested the effect of carbon dioxide, which is usually around 400 ppm outdoors, on 22 participants at 600, 1,000, and 2,500 ppm. Results of the tests indicated the “direct adverse effects of CO2 on human performance may be economically important and may limit energy-saving reductions in outdoor air ventilation per person in buildings.”
“A lot of institutional buildings are not up to code — that’s a given,” said Phil Kimble, product development manager at Jackson Systems LLC. “I think as the rules change, and as codes get more stringent, they’re going to have to face these things.”
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John Bickers, director of product management at Testo USA Inc., agreed that many school buildings are likely not up to code. “Schools probably should be checked more, especially given the number of people in the building, and probably also because many of the schools are older and don’t really have forced air or air conditioning, and are using steam or hot water,” he said.
“They don’t really realize they should be monitoring CO2 levels to ensure good IAQ,” said Kevin Basso, chief engineer at General Tools & Instruments.
Ken Misiewicz, CEO of Pleune Service Co., Grand Rapids, Mich., said too much fresh air creates a contracting problem that can be just as problematic as not enough fresh air is for building occupants.
“Since the equipment, like a rooftop unit, has to be sized for maximum load including fresh air, late spring to early fall leads to too much fresh air, which translates to wasted energy and inadequate humidity removal,” Misiewicz said. “That can cause a spike in mold growth under the right, or maybe we should say wrong, conditions. But, on the flip side, older schools using the ‘operable windows’ approach are frequently lacking in fresh air when classrooms are full.”
Testing, Logging IAQ
As studies continue to show the ill effects of poor IAQ on student concentration, performance, and health, school staff and contractors are increasingly turning to sensors and data loggers to assess and monitor IAQ in schools.
“A lot of this is driven by test scores, believe it or not,” said Joe Jackson, vice president of custom controls at Jackson Systems. “If they’re not where they should be, the school may start looking at the IAQ with handheld devices, and if they discover they have a problem, they have to do something.”
“You have to get a snapshot in time — two weeks or a month, or whatever it is — so you know what you’re dealing with,” said Evan Lubofsky, director of marketing communications at Onset Computer Corp. “What our data loggers do is measure and record parameters like temperature, humidity, and CO2, then put the data into graphs that the contractor can analyze.”
“Testo has a dedicated CO2 meter, which will do a spot check and give you the minimum, maximum, and mean levels over time,” Bickers said. “The HVAC contractor is going to use CO2 measurements to set the fresh-air ratios and know how much fresh air he should be introducing into the ventilation system.”
Bickers added that Testo also has data loggers that can monitor temperature and humidity, which are key components of institutional IAQ and comfort.
In addition to manufacturing portable meters, General Tools has a mounted CO2 meter that can be wired to a relay, which will open up a fan when CO2 levels reach a certain concentration, Basso said.
“That one is used primarily for industrial areas and even in schools, while the portable model is used by contractors or people who are on the move,” he said. “They’ll go from room to room, building to building, taking measurements. It also has the ability to hook up to your computer with some software, in which case you can download the information.”
A Balancing Act
Once a school has established its IAQ needs, the next step is figuring how to bring in fresh air without breaking the bank. In most cases, industry leaders agree this is easier said than done.
“If you have to temper the outside air, you have an additional load on the building, and you’ll have higher utility bills,” said Tom Jackson, CEO of Jackson Systems. “Unfortunately, there’s not a simple answer.”
Mike Barcik, director of technical services at Southface Energy Institute in Atlanta, said balancing the need for more outdoor air with the desire for energy efficiency in schools is difficult, but it can be done.
“You must pay a price to condition every cubic foot of outside air you bring into a building,” he explained. “We obviously want enough ventilation to keep people healthy and productive, but don’t want to over ventilate, since that carries a high energy price tag, especially in humid climate areas like the Southeast.”
Barcik suggested installing energy recovery systems and occupancy sensors in schools, though he admitted, “it is probably easier to design this in from the beginning and harder — but not impossible — to retrofit this to existing buildings.”
Steve Moon, owner of Moon Air Inc., Elkton, Md., also recommended energy recovery systems for schools looking to increase the amount of outside air intake.
“Most of the schools in our area have older equipment that does not have fresh-air make up dampers at all,” he lamented. “There are many fresh-air devices on the market today to help with this as add-on equipment, including heat recovery ventilators.”
Greg Crumpton, president of AirTight Mechanical, Charlotte, N.C., also suggests school officials consider using ERVs and heat wheels when considering efficient ventilation. “Both of these concepts allow you to drastically increase, via efficient operation, the amount of outside air that requires a lot less conditioning, thereby cutting energy consumption,” he said.
Crumpton also suggested contractors “work with an engineer who understands the energy code and is current and fluent with IAQ normal practices.”
Misiewicz also acknowledged that installing energy recovery ventilators (ERVs) is beneficial, though he suggested coupling the devices with a demand-based ventilation solution. “Managing the amount of fresh air based on actual readings is the best way to balance energy consumption with IAQ,” he said.
Maintenance is Key
While ventilation is important to IAQ, Alan Wozniak, president and CEO of Pure Air Control Services Inc., Clearwater, Fla., said a lack of maintenance can have a profound impact on IAQ and energy efficiency, even when enough fresh air is being brought into the school.
“With deferred maintenance increasing as a result of the economic conditions, the ventilation cleanliness, AHU (coils) cleanliness, and overall air conveyance system conditions have eroded significantly, causing an increase in microbial and particulate burden, and creating potential respiratory distress for building occupants,” he explained.
Wozniak suggested a deep steam cleaning of the evaporator coils and blower assemblies at more than 350°F, as opposed to using the soap-and-water method. He attests that this improves IAQ and significantly increases the energy efficiency of the unit. “The typical payback with a Pure-Steam Coil Cleaning method is approximately eight to 12 months,” he added.
Forrest Fencl, president of UV Resources, Santa Clarita, Calif., said ultraviolet (UV) technology can also help keep the coil clean, thereby improving IAQ and boosting energy efficiency.
“It’s a matter of run time, so the more efficient the heat exchanger is, the less the run time of the unit,” he explained. “Even if the unit runs all the time, if the system is inefficient, the inside of the classroom will be potentially warm and clammy because it doesn’t dehumidify, thus the comfort level will be low.”
UV can also sanitize the air and cut down on potentially harmful pollutants, such as mold, when installed directly in the ductwork, he added.
In addition to preventive maintenance, Bob Keingstein, president of Boss Facility Services Inc., Ronkonkoma, N.Y., emphasized the importance of looking into a wide array of IAQ solutions to find the best fit for each school. “One such system would be ionization technology, as provided by Atmos Air Systems,” he said. “We have used this product with great success.”
Moon also emphasized the effect maintenance can have on IAQ and system efficiency.
“One thing that happens in this type of service is, as the equipment begins to age and efficiency begins to drop, the service tech will turn off existing make up, if there is any, to raise the efficiency to cool the same area.”
That, Moon said, can be downright dangerous to the health of the people inside the building.
“Most do not realize the health factors that are being compromised,” he said. “Just don’t do it. Focus on maintenance and proper repairs, not quick fixes.”
Finding Solutions
Though commercial ERVs are an efficient way to extract temperature and humidity from exhaust air and apply it to the unconditioned air entering the school, the price tag of most ERVs may eliminate them as an option for cash-strapped school districts. Jackson Systems, which routinely provides ventilation solutions to schools across Indiana, offers another, simpler solution.
“We have our Econo-Pack economizer, with a primary purpose of providing free cooling during the cooler months using the outdoor air instead of using mechanical cooling,” Tom Jackson said. “It does have minimum position control, so you can always bring in a little outside air. If you have an older system and you just need the ability to do economizing, as well as control some outside air, you can do that.”
Honeywell Environmental and Combustion Controls also offers a demand-based ventilation solution in the form of its JADE economizer controller module, which works with the existing air handler and economizer to bring in only as much fresh air as the building needs, helping to save energy and money.
“Everyone knows how great good ventilation in schools is,” said Barbara Dean-Hendricks, director of product marketing at Honeywell. “Our controllers help bring in fresh air through the air handler, which is frequently equipped with an economizer or ERV. Our JADE controller senses both outdoor temperature and humidity, so the school can do demand-controlled ventilation.”
An optional CO2 sensor can also be installed within the duct-work leading to the JADE controller, prompting it to increase ventilation when necessary, in order to decrease CO2 levels in the school, she added.
“We offer a complete demand-control ventilation solution — the sensors, the controller, and the actuator to control the economizer. Appropriate ventilation strategies, plus the free cooling, provide the maximum amount of savings that you can get from the unit.”
Bringing ample fresh air into schools is necessary for creating a healthy learning environment for students and staff. With input and help from HVAC contractors and other industry professionals, school districts can find affordable and effective ways to improve their students’ health, performance, and overall comfort.
“Improving air quality definitely impacts students’ scores on tests,” Joe Jackson said. “If we can do it without spending more money each month, why wouldn’t we do it?”
Publication date: 8/5/2013
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