Technology drives HVAC, plumbing changes in K-12 school

Respondents:

• Luis Alvarez, PE, Electrical Engineer, Associate, Page, Austin, Texas
• David Bonaventure, PE, CEM, Principal, Salas O’Brien LLC, Baton Rouge, Louisiana
• Lawrin T. Ellis, PE, LEED AP, Managing Principal, TLC Engineering Solutions Inc., Fort Myers, Florida
• Keith Hammerschmidt, PE, Senior Project Manager, RTM Engineer Consultants, Overland Park, Kansas
• Scott Peck, PE, Vice President, Peter Basso Associates, Troy, Michigan

Luis Alvarez, PE, Electrical Engineer, Associate, Page, Austin, Texas, David Bonaventure, PE, CEM, Principal, Salas O’Brien LLC, Baton Rouge, Louisiana, Lawrin T. Ellis, PE, LEED AP, Managing Principal, TLC Engineering Solutions Inc., Fort Myers, Florida, Keith Hammerschmidt, PE, Senior Project Manager, RTM Engineer Consultants, Overland Park, Kansas, Scott Peck, PE, Vice President, Peter Basso Associates, Troy, Michigan

Describe a recent project in which you addressed indoor air quality issues to account for COVID-19 health concerns.

Lawrin T. Ellis: The primary response to controlling COVID-19 for both new construction and HVAC maintenance replacement projects in local school districts has been to transition from MERV 8 to MERV 13 filters.

Because many schools were closed for extended periods due to COVID-19, how have you addressed the water issues, such as bacteria growth in pipes? Other health and environmental concerns?

Lawrin T. Ellis: We have not experienced water quality issues locally. Also, during shutdown and periods of inactivity, the school districts were diligent about sanitizing indoor environments.

What unique heating or cooling systems have you specified into such projects?

Lawrin T. Ellis: Our projects are centered primarily in central and south Florida. The coastal regions tend to be semitropical and have very mild, short heating seasons. Consequently, our biggest challenge is year-round dehumidification required for ventilation. When the opportunity arises and those are few, we use proven air purification systems when project budgets allow.

What types of unique building pressurization have you designed in K-12 schools?

Lawrin T. Ellis: Our designs include building pressurization systems that include airflow offset and building differential pressure transmitter controls. Most of the schools are single or two-stories with a few three-story locations, so we do not experience intense stack effect. The DPT controls offset what we do experience.

What unusual or infrequently specified products or systems did you use to meet challenging heating or cooling needs?

Lawrin T. Ellis: Most of the school districts use chilled water and electric strip heat. A couple use boilers and heating-hot water. For direct expansion campuses, we try to incorporate variable refrigerant flow where budgets allow. We’ve also introduced chilled beams as an alternative for classrooms primarily to limit, if not eliminate, introducing cross-contamination through mixed return air. There is some interest, but no actual chilled beam systems to date.

Keith Hammerschmidt: We have designed various schools with the use of VRF system paired with a dedicated outdoor air system. With providing this design we are able to provide an efficient system while giving individual control and provide a healthy building with proper ventilation.

How have you worked with HVAC system or equipment design to increase a building’s energy efficiency?

Lawrin T. Ellis: We constantly strive to minimize building energy consumption and cost. Every dollar that can be saved can be applied directly to the classroom environment for the benefit of the students.

What best practices should be followed to ensure an efficient HVAC system is designed for this kind of building?

Lawrin T. Ellis: At a minimum, meet and when possible, exceed local and national energy codes. That not only includes the MEP systems, but the envelope requirements. Our biggest challenge is compensating for architectural designs that do not take advantage of favorable site orientations (not always possible) and not adhering to prescriptive envelope thermal and solar performance.

What are some of the challenges or issues when designing for water use in such facilities?

Lawrin T. Ellis: The biggest challenge designing domestic water and sanitary sewer systems is for campuses that require an Enhanced Hurricane Protection Area in conjunction with local jurisdictions. Following Hurricane Irma, new and retrofit EHPAs have included water storage and pumping systems for flushing toilets as well as sanitary lift stations in the event that a local water utility is compromised. Both systems require cross-connection emergency power associated with an EHPA.

When designing school natatoriums, what challenges have you met and how did you solve them?

Lawrin T. Ellis: None of the central and south Florida schools we’ve provided engineering services for include natatoriums. The few campuses that do have pools are all outdoor pools and facilities.

Keith Hammerschmidt: School natatoriums can be challenging because of the multiple uses of the space. The pool will see various types of use throughout a day from a single class to a swim team practice to a swim meet with spectators. During design, the team has to account for all types of space use as this will all impact how the mechanical dehumidification unit reacts to the changing space.

Do you have experience and expertise with the topics mentioned in this content? You should consider contributing to our WTWH Media editorial team and getting the recognition you and your company deserve. Click here to start this process.