HVAC

Webinar recap: Is your building ready for back-to-school?

As schools across the country have kicked off the 2020-2021 school year, there has been a wide variety of strategies and arrangements implemented from fully remote learning to hybrid schedules to fully in-person classrooms.

By Henderson Engineers October 4, 2021
Courtesy: Henderson Engineers

As schools across the country have kicked off the 2020-2021 school year, there has been a wide variety of strategies and arrangements implemented from fully remote learning to hybrid schedules to fully in-person classrooms. Henderson Engineers and Henderson Building Solutions are trusted advisors for more than 170 districts nationwide, and also parents to school-age children and spouses/family members of teachers and administrators. Understanding how building systems can impact the safety and success of learning during a pandemic is more than just about good client service, for Henderson Engineers, it’s personal.

Earlier this summer, several Henderson experts came together for a panel discussion titled Is Your Building Ready for Back-To-School? The recording is available for viewing on their website; however, below they’ve compiled some of key takeaways from that conversation.

Filtration and ventilation

Health and wellness have always been at the forefront of design, but things like MERV filtration, outside air ventilation, and water quality weren’t always top of mind for parents, teachers, and students until recently. Several institutions, including the Centers for Disease Control and Prevention (CDC), the American Institute of Architects (AIA), the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), have created great resources to help the design community and facility operators and districts.

  • The CDC’s resources highlight the same recommendations we are seeing in everyday life: practice social distancing, increased hand hygiene, face coverings, etc.
  • ASHRAE is a resource we really pay attention to from the engineering side of things. Their recommendations focus on mitigating airborne transmission of the virus through strategies such as filtration, air flushing, and occupancy schedules.
  • The AIA’s recommendations include strategies related to capacity, wayfinding, scheduling, and other topics associated with how spaces are used.

To implement mitigation tactics most effectively, we have to first truly understand how viruses spread. To do that, Henderson’s Chief Technical Officer, Dustin Schafer, developed a cause map that looks at the three transmission paths for COVID-19 in the built environment. The map shows how the virus can be spread and includes green boxes that call out mitigation technologies and strategies.

Increasing ventilation as a means to improve indoor air quality (IAQ) isn’t a new topic of discussion in schools. There are several studies that demonstrate cognitive improvements and other positive impacts, such as improved sleep and fewer sick days, on students and staff.

  • Improved Ventilation Case Study: At Lawrence High School, Henderson is working on a three-year, multi-phase renovation project which includes retrofitting the entire HVAC system and increasing the ventilation in all classrooms. This school had 1950s-style unit ventilators that are being replaced with a VRF decoupled dedicated outside air system. During early planning and design, the school board was interested in studies that show the positive impacts associated with improved ventilation.
  • Portable Air Purifiers Case Study: We recognize that not all schools or districts have the budget or ability to upgrade entire systems. But there have been studies done, like one from New York University, where comparatively inexpensive, portable, plug-in, HEPA air purifiers actually resulted in higher test scores. In 2015 there was a massive natural gas leak at the Aliso Canyon storage facility in Porto Ranch, California, that continued for about four months. To combat the potential negative impact on IAQ, all the schools within a five-mile radius of the leak brought in portable air purifiers – totaling more than 1,700 units. At the time these units were brought in, air testing showed that the pollution caused by the leak wasn’t really affecting the air quality in and around the schools, but these filters were still filtering out the standard pollutants inside these classrooms like bacteria, allergens, etc. The New York University study found that there was a statistically significant improvement in cognitive function with the use of these units. And when compared to other methods (such as classroom size reduction), the cost to maintain and operate these filters each year outperforms other methods in a cost-benefit analysis. This could be a great option for low-income or underprivileged areas which often exist in urban areas with higher pollution as well as districts with budgetary restrictions.

It’s not just filtration and ventilation that can have an impact on mitigating the potential spread of infection — temperature set points and relative humidity also play a role in occupant safety and comfort. How schools approach these factors will depend heavily on the climate of the area where the school is located, though.

  • The survival of microorganisms is significantly limited when relative humidity is kept between 40-60%. However, maintaining that level using mechanical systems will look very different for a school in Florida compared to a school in Las Vegas or Denver.
  • Increasing ventilation also depends on the location of the school as looking at not just the outside air temperature but also the level of pollution in the air. The goal in these efforts is to meet the ASHRAE minimums for ventilation, then to exceed them where possible based on these factors.

General prep

Some of the changes outlined above require an investment that we realize not all districts have the budget to support. However, there are also several approaches which require little or no cost.

  • Make sure all equipment is working properly, including all fans (supply, return, and release fans). You also want to verify your outside air dampers are modulating open and closed properly and that economizers ​are being maximized to take advantage of shoulder seasons.
  • A good idea before reopening a school building that’s been closed for an extended amount of time is to start running the systems about a week before reopening. This allows you to make sure you’ve got fresh air in the space and the building is “breathing” properly before it’s fully occupied. Similarly, extending the time in which you regularly operate your systems by a couple hours, both pre- and post-occupancy, is beneficial by utilizing increased ventilation and air flushing as an infection transmission mitigation strategy.
  • If your system has racks that can accommodate them, upgrading your filters to MERV 13 is a much simpler change than trying to retrofit HEPA filtration, while still providing added protection to the air.
  • During a pandemic especially, it’s important to verify faucets and soap dispensers are operational, that the hot water heaters are functioning properly, etc. During a time when hygiene is of heightened importance, conducting these basic checks can make a difference.

There are also some higher cost considerations for schools or districts that either are already experiencing performance issues or have been given additional budget to ensure the school buildings are safe for occupants.

  • Having a Test & Balance professional verify fans are operating properly and matching design specifications with regard to outside air and building pressurization.
  • Retro- or re-commissioning your facility by hiring a commissioning agent to come in and test all these systems and controls. The agent will verify everything is operating correctly and create an issues list of items that could or should be addressed. The scope varies widely between clients, but can be an excellent investment to optimize existing building systems and functionality.
  • Installing UVc as a germicidal intervention within air handlers is a proven method for inactivating microorganisms in the air stream, and is relatively straightforward to retrofit.
  • Many schools already have a building monitoring system and the information coming from this system can be utilized to run trends in each space and confirm all areas of your building are operating within the suggested ranges for temperature, humidity, and beyond.

Technology

One of the key things we can’t risk failing right now is technology. Technology was already a vital part of education, and now with districts and schools offering remote or hybrid learning set ups, it’s more critical than ever. The good news is that most schools already have the equipment they need to support distance learning. However, complying with CDC recommendations also requires technology, whether it’s digital signage for wayfinding or reminders to social distance, or infrared or thermal imaging cameras that can be used to check temperatures. When utilizing infrared or thermal imaging as temperature monitoring, there are several important considerations.

  • Understanding the guidelines from groups like the FDA with regard to the type or quality of equipment before investing.
  • The need for additional components, like a “blackbody unit” which sets the standard temperature for the system to base its measurements on, and a computer or monitoring station equipped with the software that can read the data from the equipment and deliver a meaningful result.
  • If a person shows an elevated temperature, this measurement would need to be verified by an actual thermometer.
  • Finally, with these types of devices, since they relate to health information, they require some policies to protect people’s personal data.

Districts and schools are all tackling pandemic learning differently; however, by and large there are three general approaches: traditional face-to-face, hybrid face-to-face/online, and fully remote/online.

  • In a traditional face-to-face classroom, the number of students is not limited. Instruction includes teacher and student interactions, both one-on-one and in group settings as well as immediate, real-time engagement, back-and-forth discussions, group work, presentations, etc. Technology in these classrooms includes standard audio (amplifier/speakers/microphones) and video (projectors/interactive boards/digital displays) equipment, data/Wi-Fi connection, and tablets and/or laptops that can be used in class by students for work on websites. Currently this arrangement is considered to be high risk due to the group size.
  • In some face-to-face classroom arrangements, class sizes are smaller and include some considerations for social distancing. In reality, this can exist as a “learning space” that’s not necessarily in a classroom setting, like a cafeteria, gymnasium, or even outside. Some additional technology could include access points on carts, one-to-one student-use tablets or laptops, even potential mobile hot spots that can be checked out for home use if the student doesn’t have access to the reliable internet outside of school.
  • Another common arrangement is a hybrid face-to-face/online learning where some students are at home while some are in-person. In this arrangement much of the same technology will be utilized with the addition of a webcam set up. This way students who are joining from home can interact with the teacher. In practice, the amount of time spent on a video call varies by age and district; however, almost all hybrid or remote settings involve a video component. This also means considering the bandwidth available to the school due to an increase in the number of devices requiring connectivity.
  • In a fully remote/online situation, the setup will vary depending on whether the teachers are able to be in the classroom to teach to student who are all at home, or if teachers will need to be teaching from their homes like they did in the spring. However, in cases where teachers will be using prerecorded session, having a scheduling utility or scheduler for the “studio” area where these sessions are filmed can help ensure proper social distancing and time for disinfecting spaces between occupants.

This article originally appeared on Henderson Engineers’ websiteHenderson Engineers is a CFE Media content partner.


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