Engineering in K-12 schools
Engineers offer practical advice and best practices on how to design HVAC, electrical, lighting, and fire protection systems in K-12 schools.
- Keith R. Hammelman, PE, Vice president, CannonDesign, Aurora, Ill.
- Robert V. Hedman, PE, LEED AP BD+C, Senior associate, Kohler Ronan LLC, Danbury, Conn.
- Pete Jefferson, PE, LEED AP, HBDP, Principal/vice president, M.E. Group, Overland Park, Kan.
- Essi Najafi, Principal, Global Engineering Solutions, Rockville, Md.
- Rodney V. Oathout, PE, CEM, LEED AP, Regional engineering leader/principal, DLR Group, Overland Park, Kan.
- Sunondo Roy, PE, LEED AP BD+C, Vice president, CCJM Engineers, Chicago, Il.
CSE: Please describe a recent K-12 school project you’ve worked on—share details about the project, including building location, size, etc.
Keith R. Hammelman: A project for the Cayman Islands Ministry of Education, High School Campus System, consisted of three campuses, each housing 1,000 students. The 185,700-sq-ft Clifton Hunter Campus has seven campus buildings housing administration, a gymnasium, classrooms, and performing and applied arts spaces. The construction magnitude was unique because of the relatively small Caribbean location and the building’s requirement to withstand a Category 5 hurricane (requiring emergency provisions for stand-alone operations). The project has on-site diesel fuel generators, fuel campus electrical distribution, hurricane cisterns for drinking and flushing water, and a full-campus chilled water system to last a minimum of five days. The campus design also faced challenges by local and maintenance forces that require relatively simple variable air volume (VAV) air handling units and air-cooled chillers.
Robert V. Hedman: Guilford High School in Guilford, Conn., is a new 215,000-sq ft school that was designed to meet the Connecticut High Performance Building Standards, which is equivalent to a U.S. Green Building Council LEED Silver rating. In addition to the standard programs, Guilford High School includes a robotics lab, welding shop, automotive shop, and a greenhouse.
Pete Jefferson: We got to celebrate the opening of three new PK-12 projects in eastern Colorado last fall. They ranged in size from 55,000 sq ft to 80,000 sq ft, and all are replacing existing facilities that were in really poor shape.
Sunondo Roy: CCJM is involved in the design of an annex to an existing Chicago Public School, Bell Elementary School. The project scope initially required tying plumbing and heating into the existing school’s infrastructure while the air side HVAC and electrical were to be new stand-alone RTU and new utility service. Based on existing conditions and infrastructure capabilities as well as field conditions, the plumbing and fire protection for the new annex ended up being served by a new utility service as well.
Essi Najafi: The historic 331,900-sq-ft Roosevelt High School in Washington, D.C., was constructed in 1932 and houses a traditional 9th through 12th grade high school program, as well as an evening part-time program for young adults. Combined, the two programs serve more than 1,500 students through a variety of programs and classes. The renovation program focuses on the reuse of the existing historic building’s resources, including the main academic building, gymnasium, and auditorium, and the insertion of new, contemporary facilities to form a completely new 21st-century, high-performance school.
Global Engineering Solutions is providing mechanical, electrical, plumbing (MEP) and fire protection engineering services for the design of new, high-performance building systems throughout the school. Originally conceived as LEED Gold, the project provided a unique opportunity to achieve LEED Platinum in a historic facility with a minimum increase in cost.
The historical significance of the school meant that little could be done to change the existing envelope, skylights, or roof to improve energy efficiency. However, the school’s location next to an open field allowed for the use of a geothermal system. The new system is a geothermal heat recovery variable refrigerant flow water-sourced system that uses geothermal heat dissipation via 253 vertically drilled heat dissipating ground wells, indoor variable refrigerant fan coil units connected to variable refrigerant flow water source heat recovery units, along with indoor/outdoor water sourced heat pump air handlers for fresh air. The system will be zoned so that heating or cooling within specific areas in the facility can be adjusted based on need and occupancy without impacting the remainder of the building or the overall HVAC system. The modularity of the system increases its reliability, while being less expensive to construct or operate than other geothermal systems.
The HVAC system serving the school’s atrium and natatorium required a careful design approach to realize the maximum possible energy efficiency and minimize energy usage. The three-story atrium features glass skylights covering the expanse of the roof. From an energy perspective, the atrium has a high solar load even during the winter heating months, which provides a unique opportunity to recover the heat and use the warm air in the energy recovery heat wheels of the rooftop units to preheat cold outdoor air in the winter prior to mechanically heating the air. The natatorium will also receive a dedicated system that has the ability to heat the pool water when the natatorium space has excess heat to expel.
The electrical system features a roof-mounted 265 kW photovoltaic solar panel system with the capacity to produce 345,000 kW per hour. The installation includes 864 solar panels, each producing 305 W. Interior lighting will be controlled by digital lighting control panels programmed so that all lighting, except emergency nightlights, are automatically turned off outside normal operational hours.
In addition, a solar thermal water heating system will produce adequate hot water to heat showers, bathroom lavatories, and kitchen facilities. The system uses evacuated tube technology to capture transfer solar energy to a circulating water loop. Because the school’s hot water demand is higher during the winter months when the school is in full session, and lower during the summer when the school is in recess, the system’s solar collectors will be placed to provide optimum energy capture during the winter months when the sun is at its lowest.
Water use will be reduced by 30% to 35% throughout the facility through the use of high-efficiency water closets, urinals, lavatories, and showers. A rainwater reclamation system will filter the water, process it to remove biological organisms and chemicals, and store it in underground cisterns for nonpotable use. An ultraviolet treatment will reduce the concentration of chemicals and biological organisms found in the water, and a dye injection system will be used to identify the water as reclaimed.
In summary, it is estimated sustainable features woven into the design of the MEP and fire protection will account for more than half of the points necessary for this historically significant facility to achieve LEED Platinum.
Rodney V. Oathout: An exciting DLR Group design that opened in August 2013 is the new Muriel Williams Battle High School in Columbia, Mo. This 301,500-sq-ft high school will serve 1,850 students in grades 9 through 12. It will allow the district’s two existing high schools that currently serve grades 10 through 12 to include 9th grade students. The design encompasses many sustainable features, including a ground-source heat pump system.
CSE: How have the characteristics K-12 school projects changed in recent years, and what should engineers expect to see in the near future?
Jefferson: We are seeing a lot more specialized curricula going into school programs, particularly science, technology, engineering, and math (STEM) programs. A huge focus of school districts now is “21st century learning.” Of course, we have to work with them to understand what that concept means to them and our architectural partners, because it can vary dramatically.
Oathout: The diversity of spaces and expectation for high-quality indoor environments continue to be top priority when designing modern K-12 facilities. The evolution to student focused instructional methods will expand the need for flexible use spaces requiring systems to be more robust to achieve these requirements. Many K-12 facilities are used year-round by multiple community and public users’ groups from before sunrise to well past sunset. The impact on design from the 365 virtual 24/7 use is that systems must provide quality indoor environments for all weather conditions, a much wider range of occupancy, with a level of redundancy not found in school designs 20 years ago.
Najafi: School systems have seen a high increase in sustainable practices throughout the recent years. This is due to a combination of many factors. Studies have shown that students learn and perform better in environments that are thoughtfully and sustainably designed with appropriate light, comfort, ventilation, and noise levels. This has raised the bar for K-12 design. LEED has become a standard for many schools as the expectations of the classroom environment have increased in order to improve learning. In addition, owners are becoming more concerned about long-term operations and maintenance costs. We’re seeing more sustainable and design-savvy clients in the school systems. An increase in funding to support better built spaces has also allowed quality designs to be realized. As the design industry progresses, so will the sustainability and design criteria, particularly in the K-12 market. Engineers can expect to see a continued upward trend in sustainability and thoughtful design within K-12 schools.
Hedman: Energy efficiency and LEED are the driving forces on all school projects that we are currently designing. Municipalities are using the schools as an example to the community on sustainability and energy efficiency. With future energy codes and communities embracing energy-efficient buildings, engineers need to become more familiar with how to design to meet these parameters while staying within budget.
Roy: First, the production has shifted from Autodesk’s AutoCAD to Revit and its attendant complexities and coordination. Although the promise of Revit is obvious with greater integration and coordination of architectural and engineering design, the final execution is still lacking, primarily due to proficiency issues of both architectural and engineering users. The added effort is not benefitting the overall project as clients are generally not able to use the Revit model and, in many instances, contractual and liability issues limit sharing of the models with the installing contractors. The architecture/engineering and the contracting sides are still not effectively integrated. Secondly, the adoption of the 2012 version of the International Energy Conservation Code (IECC) combined with the more stringent energy guidelines of LEED v4 have tightened up design options to exceed a baseline ASHRAE 90.1-2010 model versus ASHRAE 90.1-2007 for LEED v3. Each incremental increase in energy-efficiency requirements necessitates even greater integration and coordination of building envelope and internal mechanical and electrical systems. One side or the other, alone, cannot provide the necessary energy savings.
CSE: How does engineering systems in K-12 schools differ from colleges and universities?
Oathout: There are some significant differences between working on a K-12 facility project and a project for a higher education institution. The utility plants common to colleges and universities are larger and far more advanced than what is commonly found at the K-12 level. The demand for more sophisticated equipment in laboratory environments for higher education projects is significantly different than what is common to K-12 projects. Another difference is that K-12 projects tend to be architecturally driven so the engineering teams commonly fill a role as a consultant. There are more instances for the engineering professional to be the project leader on a higher education campus.
Roy: Typically, elementary schools don’t have the in-house maintenance and engineering to support very complex systems. Even many high schools have limited resources to fully staff permanent building engineers with the experience necessary to optimize and effectively operate highly complex mechanical and electrical systems. It is imperative for design engineers to keep this in mind when designing systems to ensure the systems that are being proposed and designed can be economically maintained and operated as intended.
Najafi: Colleges and universities tend to have multiple buildings with a wide variety of uses. Students attend class in designated classroom function buildings. Students attend sporting events and use gym spaces in designated athletic buildings. Science laboratories are often built into a laboratory of science and technology type building. With K-12 schools, we’re taking all of these spaces and combining them into one building. This requires careful zoning and an attention to space usage, scheduling, and proper system selection for each individual space within the building. K-12 buildings must be versatile, robust, and flexible in space usage, unlike almost any other type of building. Designs for K-12 buildings must be versatile, robust, flexible, sustainable, and affordable.
Hedman: We believe that systems types are similar; however, colleges and universities have dedicated the staff to exclusively maintain and operate MEP systems.
Jefferson: Decentralized systems are the norm in our K-12 projects, but fairly rare with our university clients. As a designer, if I’m connecting into an existing central plant at a university, it’s sometimes tough to get creative with the systems approach, especially if the client requires adherence to a very specific technical standard. I think that K-12 often offers more opportunity to be really creative and find the best possible set of systems for their district.
CSE: Please explain some of the general differences between retrofitting an existing school and working on a brand-new structure.
Hammelman: The biggest and most obvious difference is retrofitting is constrained by the existing building construction. This factor will often influence or even dictate the system we can install. For example, many schools built in the mid-1950s and 1960s have a very low floor-to-floor height and minimal roof structure, which limits HVAC systems choices. With new construction, the sky—well, really the budget—is the limit. Engineers can work early and in tandem with architects to determine the optimum building layout for the client’s preferred HVAC system needs.
Roy: Retrofitting an existing school requires a preliminary existing conditions assessment that will provide the designer with a baseline for what the existing building is capable of and whether new systems can be additive to the existing or stand-alone with brand new utilities if the infrastructure cannot support the new systems. Many times, the design effort is greater for retrofits due to working around existing conditions and limitations that are exposed as part of the existing conditions assessment. However, these projects also give the designer greater insight into the maintenance and operating capabilities of the school and allow the designer to customize the design based on how he or she can expect the school to realistically operate. With new construction, designers have a clean slate to work with, although there are greater demands to establish the utility infrastructure to serve the school.
Jefferson: In any of our projects, we work diligently to first try to reduce the heating and cooling loads and find passive opportunities before we jump to active systems (HVAC, lighting, etc.). Existing buildings are usually tougher to make changes to, like upgrading the envelope. But we’ve found some of our very old building retrofits to actually be much easier to retrofit than some from the last 30 to 50 years. Before energy and artificial lighting got cheap and available, those original designers set up their projects to take advantage of daylight and natural ventilation.
Najafi: Retrofitting existing schools poses a different set of challenges, which requires a different design approach. When retrofitting existing facilities, we must consider the age and condition of existing MEP infrastructure and analyze the feasibility of re-use with regard to energy and cost efficiency. We conduct a lifecycle cost analysis of the existing systems in comparison to the new systems to determine whether renovation of the existing systems or a complete replacement is in the client’s best interest. Improving the energy efficiency in existing buildings also requires a thorough analysis of the building envelope: windows, walls, insulation, etc. We analyze both the feasibility and the cost of replacement versus adding insulation and vapor barriers to existing walls to determine the impact the reduction in HVAC loads will have on energy savings.
The constrained spaces most existing MEP systems are located in add another level of complexity when compared to new building design and must be coordinated closely. A new structure also requires analysis of envelope, lifecycle costs, and coordination, but an existing building brings that analysis to another level: there are some mechanical systems that just aren’t feasible in retrofit buildings because of the space required; and insulating existing walls is more difficult and can be more costly in a retrofit than in new construction. To provide highly efficient, cost-effective systems in renovated facilities requires first-hand knowledge of the systems on the market, and the creativity to adapt to the constraints of an existing facility. Although both new construction and renovation projects require creativity, new construction projects have a different design approach because they are more flexible.
Hedman: When designing for an existing building, engineers must pay close attention to the existing infrastructure and determine if there are any limitations in supporting the proposed architectural program. Furthermore, phasing often becomes a challenge; many times the school must continue to operate during construction.
CSE: Many schools require flexible space—building features that can be adapted to different uses as the school’s needs evolve. How do you take such requirements into consideration?
Jefferson: Flex space has to be adaptive to future needs, but even daily needs change. We’re seeing libraries become “media centers” or “multipurpose areas.” We’re responding to that with systems that are adaptable, like multiple levels of lighting, but also are user friendly. The user-friendly concept is really important in these spaces. Unlike a typical classroom with a dedicated teacher, nobody “owns” this space. They need to be able to figure out quickly how to get to the right levels of light for whatever it is that they are doing.
Hedman: Designing for these types of spaces for flexibility is a challenge. Appropriate systems must be designed such that the infrastructure can support program changes with minimal impact.
Roy: Obviously, it is critical to know these requirements as early in the design process as possible. Generally, looking at the design holistically and understanding the commonalities and differences of the flexible spaces and their design impact allows designing a more generic design in some cases and a more specific design solution in others, depending on the balance of commonalities and differences. We typically combine dining rooms and gymnasium-type multipurpose spaces because they are seldom used fully loaded concurrently and the ventilation loads are similar, allowing the common system to serve both.
Najafi: As engineers, we advocate for smart engineering design choices early in the design process. This means that we work closely with the architect and owner to understand individual space usage within the building, building schedules, design approach, capability of owner’s maintenance staff, owner requirements, and so forth. Understanding the intricacies of how each individual space will be used and the scheduled of use prior to ever submitting a schematic design is a huge part of this. With this kind of information, the MEP systems can be integrated into the architectural design very early on to provide systems that work with the building instead of against it.
Many schools are used as mixed-use spaces where the community has access to the spaces both after hours and during the summer months—and when it comes to schools, no two schools are alike and no two spaces within a school are alike. Understanding how a school is going to be used throughout the year is important if we are going to work modularity and flexibility into the mechanical systems.
If, for example, only 20% of the school is being used, the base building systems need to reduce to 20% of the load to realize energy savings. When using geothermal and water source systems, we need to have enough pumps with variable frequency drives (VFDs) to provide appropriate turn-down on the water side. With air-cooled systems such as packaged rooftop units for gymnasium spaces, we often need to provide single zone variable air volume systems with demand control ventilation so that the system functions appropriately when the space is in full use, but can also reduce their energy use when the spaces are not fully occupied. An intricate and early understanding of the building gives us the ability to design systems with modularity and flexibility to meet the ever-changing demands of a K-12 school.
Oathout: The requirement for flexible spaces that differ from traditional classrooms is a growing trend in K-12 facilities. Communication with the users and the full design team is the key. DLR Group uses an integrated design process that includes the engineering teams very early in the process so expectation from the users can defined and developed well in advance of the detailed design. Once the use of a space use is understood, an efficient, flexible, and robust system can be selected that will likely be different than what was designed 20 years ago.