The looming onset of winter is raising concerns about indoor air quality, especially concerning how the coronavirus and flu season might interact. This is especially relevant for schools that host large amounts of students circulating in and out of the building. As schools manage reopening, intelligent technology can help them in their fight for indoor air quality and the health of their students and staff.
Advice From The ASHRAE Schools Team
Corey Metzger is the Schools Team Lead for ASHRAE’s Epidemic Task Force and is the founding principal of Resource Consulting Engineers LLC. ASHRAE’s School Team has produced guidance specific to schools/universities that contractors can consult when serving schools. ASHRAE’s Epidemic Task Force Building Readiness Team has also released guidance.
“The key things that the Epidemic Task Force has recommended is making sure systems are operating as intended, and then to look at those systems and determine if additional ventilation can be incorporated into operation,” he said. He explained that the goal of this is to increase outdoor air flow rates. The schools should also be looking at potential improvements to air filtration in their systems. He explained that ASHRAE’s recommendations are built on the assumption that the educational facility is meeting ventilation thresholds in accordance with ASHRAE Standard 62.1 or the equivalent local code.
Metzger explained that one of the key obstacles to overcoming air quality challenges in schools is the condition of education’s HVAC systems. A June 2020 U.S. Government Accountability Office (GAO) report stated that an estimated 54% of public school districts are in need of updating or replacing more than one building system/feature.
“An estimated 41% of districts need to update or replace HVAC systems in at least half of their schools, representing about 36,000 schools nationwide that need HVAC updates,” stated the report.
Metzger said that ASHRAE recommends strategies for improving air quality in schools, but all of these strategies might not be achievable for a given school with a limited budget.
“One of the things we have recommended directly is HEPA filter units,” he said. “Those can be terminal units that are permanently installed. It could be a portable unit that’s brought in and set on the floor.” He said that air cleaning devices can be a great way to increase effective clean air change rates, and that a HEPA filter should be efficient at removing aerosolized pathogens. However, even with this, schools don’t want the purification solutions to negatively impact air distribution. UVGI (ultraviolet germicidal irradiation) is another solution for improving air quality. Metzger added that he would advocate against reductions in ventilation rates, saying that now isn’t the time to cut outside air given the concerns about air quality and health.
Any changes to a school’s HVAC system should be carefully considered, Metzger said, since a solution like adding ventilation could be a significant problem for a school building that can’t handle it from a sensible or latent heating/cooling perspective. Building systems are complex, so they usually need to be examined on a case-by-case basis to make sure health is being preserved as much as possible.
“A number of the steps that we’re recommending are going to involve and assume that there’s some level of building automation or campus automation available,” Metzger said. He explained that ASHRAE is recommending that schools flush building air between occupancies, which would need to be programmed into the school automation system. In addition to this, school administrators can consider a plan where the systems are programmed to run at the highest possible airflow, only reducing it when supply temperatures/humidity can’t be maintained. Sensors built into intelligent units can notify administrators when a MERV filter needs to be changed out as well.
“Any of the guidance that ASHRAE is providing are mitigation steps,” he said. “We certainly recommend following guidance from other groups like the Centers for Disease Control (CDC) or State Department of Public Health.”
AI Makes Healthier Air Possible
In his article titled “Using AI to Ensure Healthy Air in School Facilities: A Key Measure to Mitigating the Spread of COVID-19 in Schools,” Omar Tabba, vice president of products and solutions at BrainBox AI, explained how intelligence can aid the safety of students and faculty.
“Regardless of building type and age, owners of academic institutions need to start by working with the HVAC equipment and BMS (building management system) they already have in place,” he wrote. “There is no time to rip and replace existing infrastructure, and most systems in place right now can support increased air circulation.” He explained that something like increasing the air changes per hour is a beginner step in using BMS to improve air quality.
He wrote that artificial intelligence can automate the process of increasing air changes and implement recommendations (such as from the CDC or ASHRAE) quickly, while also tracking and reacting to external factors such as weather and changes in the number of occupants. AI can make time-sensitive changes to a building’s system without the expense of installing new HVAC equipment.
“In addition, AI can not only help in mitigating the spread of pathogens but can simultaneously help in minimizing the energy consumption of the system — saving building owners money in a challenging environment,” Tabba wrote.
Helping Administrators See The Value
Gebin Maxey, vice president of technology at HawkenIO, said that contractors can help school administrators realize the value of investing in intelligent solutions by focusing on people’s peace of mind and their safety.
“Everyone wants to know their buildings are safe,” he said. “They want to know that all the investments that they’re making to improve their buildings are actually paying off. School administrators want to be able to prove to their teachers, students, and parents that their classrooms are safe to return to.”
He explained that products can be created to give people this feeling of security. For example, a big screen that displays “Air Quality: Excellent” in green letters will do far more to make students and staff feel safe than simply looking at a HEPA unit.
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IAQ ON DISPLAY: A screen that displays school air quality statistics will go a long way in helping students and staff feel safe.
“We think contractors will see success by having honest conversations about the capabilities of their client’s buildings, and recommending affordable solutions that not only resonate with the typical stakeholders but also communicate safety and security to the occupants,” said Maxey.
Nicholas Kyriakides, chief operating officer of netTALK Connect, said that contractors are a reliable and trusted source in the marketplace, and they should be relied upon to provide the best advice to administrators who might be otherwise unfamiliar with the technology.
“Schools need to be able to manage and track the flow of staff, students, and visitors on their campuses,” said Kyriakides. “This can be done by using technology, but unfortunately, far too many school districts lack access to such technological solutions.”
Serving Education’s Indoor Air Quality Needs
Clive Samuels, president of CoolSys, offered specific tips for contractors and technicians serving schools’ IAQ needs.
With respect to COVID 19 and HVAC systems, schools should be considering the following strategies:
• Maximum quantity of fresh air should be introduced through the HVAC systems without any override from CO2 sensors and other control strategies. During periods of low internal heat loads (whenever classes are empty), fresh air quantities should be increased beyond the design maximum values, even at the expense of interior environmental conditions. This flushing process should also be applied after normal school hours and incorporated into the overall HVAC control scheme.
• HVAC unit filtration should become an absolute priority. At a minimum, MERV 13-15 filters should be installed. These should capture 50-85% of particles in the range of 0.3 to 1.0 microns. Preferably MERV 16 or even HEPA filters should be installed in schools. Most of the existing school HVAC systems do not have the fan capability to cope with the air resistance imposed by these filters. However, schools should seriously consider increasing the fan type and horsepower to cope with this added pressure drop, due to the potential benefit of reducing the spread of this virus.
• HVAC UV-C lighting: The inclusion of adequate and properly located UV-C lighting within the return section of the HVAC systems can aid in destroying viruses. Thought needs to be given to the velocity of the airflow across these lamps and the exposure time, which should be around a second to destroy viruses. In addition, these lamps should be replaced on an annual basis, and since they can cause damage to human cells, extreme caution must be taken by the contractor and maintenance personnel to prevent exposure to energized UV-C lamps.
• Far UV-C lighting operates at a different wavelength proven to not be harmful to human cells. Consideration should be given to installing these in classrooms, bathrooms, cafeterias, etc. This strategy must be studied carefully to ensure that only approved Far-UVC lamps are utilized in occupied spaces.
• Air distribution: The CDC has now agreed that this virus is spread via airborne aerosols delivered by contagious people while speaking, shouting, and coughing. Ideally, each zone within the school should evaluate the precise airflow patterns utilizing CFD (computational fluid dynamics) to analyze airflow and the effect of changing the air velocity and flow paths to minimize contaminated air from flowing directly to personnel/students at fixed locations.
• Contractors should be adequately prepared to explain the benefits of strategies like increasing fresh air into occupied spaces, UV-C lighting, and air flow optimization, as detailed above. The use of well-developed brochures, presentations, and ASHRAE/CDC data on these subjects should motivate school administrators on the importance of these strategies, particularly during this COVID pandemic.