In the face of dwindling budgets, growing sustainability requirements, and other considerations, K-12 school projects can be a challenging—yet rewarding—area for engineers to tackle. Here, a group of experts share advice on how to handle such projects and go to the head of the class.
By Jenni Spinner, Contributing Editor
Meet Our MEP Roundtable Participants
- Manuelita E. David, Project Manager, Aon Risk Solutions, Concord, Calif.
- Dave McFarlane, President, McFarlane, Grand Forks, N.D.
- Robert Linder, PE, Owner Services Department Manager, Karges-Faulconbridge, Inc., St. Paul, Minn.
- Sunondo Roy, PE, LEED AP , Vice President, CCJM Engineers, Ltd., Chicago
- V. Todd Yates, PE, CxA, Vice President, Facility Commissioning Group, Lexington, Ky.
CSE: What challenges have you encountered on K-12 school projects that are unique from other structures?
Dave McFarlane: School remodeling projects are typically done over the summer months. This tight time frame, compressed schedule, and the number of different subcontractors that must complete their work on a phased basis or critical path makes these projects more susceptible to startup problems.
Sunondo Roy: The occupancy density is much higher than in conventional commercial projects. This leads to much higher space sensible and latent loads due to occupant density and much higher coil sensible and latent loads due to increased ventilation requirements.
Bob Linder: Remodel projects can be very challenging. Engineering fees are being pushed down, and the accuracy of the owner-provided as-built documentation is often lacking. Contractors are bidding projects tight and usually lack the inclusion of contingency for unknown conditions, leading to an increase in change order requests. Compounding these issues are the extremely short project schedules dictated by the short summer break.
CSE: How have you seen the needs of school clients change over recent years?
Roy: Administrators are much more sensitive to students’ environmental needs to ensure optimal conditions are provided for students to perform at their highest possible levels. There may be other internal and external factors affecting the students’ lives, but the classroom environment can’t be one of them.
Todd Yates: Facility managers are much more conscious of energy use and indoor environmental quality than they were a decade ago. Even in the Midwest, with below-average energy costs, owners understand that wasting energy is equivalent to wasting additional teachers or supplies. They also have a deeper understanding that poor indoor environmental conditions (ventilation, lighting, noise, etc.) have a measureable negative impact on learning. First cost is important, but long-term quality is the real goal.
McFarlane: Schools are becoming more aware of the need for improved indoor air quality and the requirement to meet new ASHRAE 62.1 fresh-air standards. Increased fresh air and the corresponding need for increased energy are stressing school systems.
CSE: Please describe a recent project you’ve worked on—share problems you’ve encountered, how you’ve solved them, and aspects of the project you’re especially proud of.
Roy: On the Federico Garcia Lorca Elementary School, we made a point of coordinating with our architect to ensure the building envelope was the best possible within the project budget. By discussing the impact of varying overall U-values for curtainwall and fenestration on the HVAC system, we were able to find a budgetary “sweet spot” between high-performance envelopes and high-performance HVAC. Additionally, the lighting and HVAC systems were integrated at the classroom level through the lighting occupancy sensor to hibernate lighting and HVAC when the rooms were not occupied. Combined with DCV at the system level and high-efficiency T5 lighting integrated with daylighting controls, the building achieved significant energy savings.
Linder: We have in-house controls expertise that often exceeds that of the installing control technician. On a recent project, we were able to provide the design engineer with the detailed information necessary to replace the manufacturer-provided air handling unit controller with the installing contractor’s controller, how to wire it as to not void the warranty, and successfully argued the requested change order to ensure the work did not cost the owner a single penny.
Automation and controls
CSE: Are schools more or less likely to implement building automation systems (BAS), and why?
Yates: Some sort of BAS has been used on every school project we have commissioned. With the variable occupancy inherent in the K-12 school environment, the ability to utilize occupancy sensors and schedules is more useful and has a shorter payback than in almost any other building type.
Linder: I don’t think I have seen a project without a BAS in the past five years. Systems are not a value-engineered (or better defined as cost-cutting) item that is taken out of the project. Owners realize the importance of the systems to operate and maintain their buildings.
Roy: Most proactive school districts are extremely savvy about the benefits of BAS as a tool for energy savings through operational efficiencies as well as an effective preventive maintenance tool to schedule routine activities and notification of building engineering staff in the event of equipment malfunction/failure. The days of the staff coming in on Monday morning to a hot or cold school are long gone.
CSE: How does implementing automated building controls in an existing structure differ from designing one for a new school?
Roy: The biggest challenge is with legacy systems in existing buildings. Changing out either the BAS or the MEP equipment is typically not an effective solution. The best outcomes are when the BAS and MEP equipment are upgraded concurrently to allow verifiable compatibility through commissioning.
Linder: Retrofitting an existing HVAC system with new automated controls is much more difficult than installing a new system. Integrating new controls onto existing equipment is difficult due to the unknowns of the equipment components and their current state of functionality. Too many engineering decisions are based on assumptions because the design engineer lacks the time, and often the experience, to truly understand the details of the existing equipment. The controls contractor usually does not have enough information to properly price the job, resulting in higher bids to ensure all the unknowns are covered.
Yates: The systems may differ due to available space to install the components. The existing building envelope may also necessitate design choices that wouldn’t be appropriate or cost effective for a new building. The BAS hardware could be exactly the same as in a new building, but the sequence of operation would be optimized to overcome the envelope conditions of the existing building. This assumes new systems are controlled by a new BAS in an existing structure. If we adjust the scenario to include existing systems controlled by a new BAS, then the capacities and condition of the existing systems could require much rethinking of the sequence of operation.
CSE: What are some common problems you encounter when working on such systems?
Linder: Owners often believe a new automation system will solve all their problems--energy costs will go down, hot and cold calls will be eliminated, maintenance costs will be slashed. They can, but only if the system is engineered properly. Time and effort needs to be spent identifying the existing equipment and components. Care and common sense need to be used to determine what can be reused, what needs repair, and what needs to be replaced.
Yates: Finding space above the ceiling and coordination between the trades is always a challenge when installing new systems in existing structures. After installation, it is often the case that some of the assumptions about the existing envelope were incorrect. If it turns out that heat loss is greater than anticipated, the BAS may be operating per design yet not maintaining the anticipated conditions.
Roy: Most times, installing high-efficiency MEP systems will not improve overall building efficiency if the legacy BAS cannot adequately monitor and control new equipment. The converse is also true with new state-of-the-art head end BAS systems installed in buildings with antiquated equipment that can’t be effectively controlled by the new unitary level controllers.
CSE: What are the most important factors to keep in mind when designing a controls system for a K-12 school?
Linder: Understand your client. Listen to their needs and get them documented on paper. Design the system to match their expectations. Sometimes keeping things simple is better. Most of the jobs we come across have elements incorporated into the system that the owner doesn’t want, understand, or need. Also, understand their aptitude for operating their system. Work with the controls contractor and owner to assign automation security levels appropriate to the ability of the user. An overridden system is doomed for failure.
McFarlane: Funds to allow for training and upgrading of current maintenance staff need to be considered. While the control sequences can be somewhat sophisticated, most building maintenance staffs are required to perform a multitude of janitorial services and maintain buildings and grounds. Staffing and the funding to allow for hiring specialized technicians or training existing staff typically is not a priority.
Roy: Know the technical sophistication of your client and design within that framework. We as designers have not done anyone a favor by designing a system that the client does not have the capacity to operate as designed.
Codes and standards
CSE: How have changing HVAC codes and standards affected your work on K-12 schools?
McFarlane: Increased ventilation requirements have created increased opportunities for our firm’s mechanical contracting side of the business as school districts strive to reduce operating costs as well as meet new IAQ requirements.
CSE: Can you name a recent challenge you encountered in this area, and how you worked to overcome it?
McFarlane: In order to reduce energy usage in classrooms, occupancy sensors were designed to not only turn off lights in classrooms but also reset VAV box settings to a standby mode. In the standby mode, lights are off and VAV airflow settings are reduced to minimize reheat. Space temperatures were allowed to increase 2 F above the occupied setpoint in the cooling mode and 2 F below the occupied heating setting point. As soon as students came back into the classroom, the space immediately reverted to its normal occupied settings and space temperatures returned to normal.
Linder: Some building officials require a commissioning report prior to issuing building certificates of occupancy. This can be quite challenging when the project was only substantially complete a day earlier, the control system is not yet complete, and school is scheduled to start in two days. We meet with the building official and explain our role in the project, review the commissioning plan, provide documentation on the work done to date, and provide a schedule outlining the remaining tasks. This usually suffices.
CSE: What’s the most important factor to keep in mind when wrestling with codes/standards issues on a K-12 school?
Linder: Understand the code in question and how to implement it correctly. For instance, did the engineer actually run the ASHRAE 62.1 calculations or did he simply count chairs and calculate 15 cfm per person because it was easier and less time-consuming?
McFarlane: The final design needs to be energy efficient and somewhat easy to operate. Since schools have occupancy loadings that have more people per square foot than normal retail or office space, fresh air requirements are increased. Because of varying space usages, occupancy loads in classrooms can change from fully occupied to unoccupied hour by hour. It is important that the final design gives the building the ability to operate under these conditions and also maintain comfort.
CSE: What types of products do you most commonly specify in such K-12 schools? Describe the UPS system, generators, etc.
Roy: A large portion of our work is with the Chicago public schools. Fortunately, they have an excellent A/E design guideline and preformatted specifications. As such, there is consistency and repeatability in UPS and generator requirements. With a guideline to provide natural gas powered generators, the environmental hassles of diesel UST and day tanks are eliminated.
CSE: How have sustainability requirements affected how you approach electrical systems?
Roy: Virtually every school we design is either explicitly a LEED-certified project or at a minimum, implicitly designed to satisfy the vast majority of LEED criteria. Designing high-efficiency lighting systems is a core component of that strategy. More and more, we are also designing in smart panels and smart metering as budgets and districts allow continuous monitoring of energy consumption.
CSE: How do you meet the stringent safety requirements school electrical systems have?
Roy: The NEC and local electrical code amendments are quite good, and meeting them satisfies most safety concerns. Designing all K-6 schools with 120V lighting is a simple design strategy that takes into account the technical capabilities of the building engineers in these schools to minimize maintenance risks.
CSE: What trends and events have effected changes in fire and life safety systems in K-12 schools?
Manuelita David: In the past few years in California, school campuses have been divided to consist of multiple schools—“small schools” or “academies”—under a single campus. Each has its own administration office and classrooms. This has affected the fire and life safety systems by requiring additional annunciation and general alarm initiation at multiple administration office locations rather than at a single location. In addition, code changes adopted over the years have required additional initiating and notification devices to the fire and life safety systems.
Roy: We are seeing changes in the technology and hardware for security systems to ensure the schools are a safe learning environment, even if the adjacent neighborhoods are security challenges.
CSE: How have the costs and complexity of fire protection systems changed in recent years?
David: The cost and complexity of fire protection systems have increased, but so has the level of reliability and protection coverage. As code changes have occurred and additional devices are being required in schools for additional protection requirements, the cost for fire protection systems has increased. The complexity of fire protection systems has increased with the additional annunciation and general alarm initiation locations. Programming has become more complex to incorporate the required event sequences. The changes in technology such as addressable systems versus conventional “hardwired” systems have also impacted the cost of systems.
CSE: What changes in mass notification systems have you seen in K-12 schools recently? What do you see changing in the near future?
Roy: Primarily in response to code upgrades, we have been specifying more integrated elevator recall/area of rescue/refuge systems with two-way audio communications and even video links in some instances. With the advent of social media networks, it seems the trend is to decentralize mass notification from structured building systems toward more free-form systems taking into account the prevalence of cell phones and smart phones.
David: Mass notification systems have not affected K-12 schools in California. The majority of these schools, if not all, have public address systems within the campus to make school announcements, and each campus has a fire alarm system. These systems are stand-alone systems with the public address system utilizing speakers, and the fire alarm system utilizing horns. Unfortunately, many schools don’t have the funding available to upgrade systems, so it is unlikely mass notification systems will have a major impact on schools in the near future.
CSE: What are some important factors to consider when designing a fire and life safety system?
Linder: In retrofit applications, do your due diligence on the code analysis. It is important to know what code the fire/life safety system was originally designed to as well as the code that is currently in effect. Meet with the code official to get his or her interpretation of the code. This detail is critical if the project is to meet the tight schedule usually associate with a K-12 retrofit.
David: Consider what jurisdiction is responsible for the school; nuisance factors; and construction elements which are often overlooked. In many states, state codes are more stringent for fire and life safety systems than county or city codes. It is also important to know which code year has been formally adopted by the authority having jurisdiction (AHJ), since code requirements may change over the years. The code year is often overlooked during the design. The nuisance factor should also be considered. Although the code dictates the use of automatic smoke detection in schools, it does allow for alternate detection. The type of detection can vary based upon using a heat detector in lieu of a smoke detector because ambient conditions would adversely affect the use of a smoke detector, such as a boiler room or shower rooms.
Roy: A code-compliant area of rescue/two-way communication system in the stairwells is a crucial system that sometimes gets overlooked until far into the design and/or code review process. Integrating raceways into the building structure is not something you can easily retrofit.
CSE: What things often get overlooked?
David: Construction elements of a school are often overlooked. A designer should know the type of flooring or ceiling being provided for the buildings. If the corridors or classrooms are carpeted and have drop-tile ceilings, they would require more audible horns than corridors or classrooms with concrete flooring and ceilings open to the slab. Designing the same amount of audible horns in a concrete corridor as a carpeted corridor would not be practical, since everything would only echo, and could cause the audibility level to be over the allowable 120db.
Sustainable buildings/energy efficiency
CSE: When working on a green school structure for a K-12 school, where do you start?
Linder: We start by meeting with the owners to define their project requirements and their commitment to sustainability. Is sustainability something they truly believe in, or is it something that was forced onto them? We need to know who, and what, is driving the decision-making process.
Roy: We start with the using agency and end users whenever possible. The process isn’t necessarily just running down the LEED checklist, but rather understanding the priorities of the client and catering the LEED solution to put emphasis where the client wants to go.
CSE: With changing awareness of sustainability issues and an increased number of products, has working on green schools become easier, or more challenging?
Roy: We have found working with educated and savvy clients who can get past buzzwords and focus on cost-effective strategies makes the process go so much smoother.
Linder: I think it is always a challenge. There has been a significant advancement in equipment and system technologies in the past few years. Much of this is due to the sustainable movement, but a large part is just due to the industry responding to the needs of the customers. Projects are not getting any easier. It is especially challenging to work with groups, such as school districts, that have multiple decision makers. People have different viewpoints and consensus is difficult to obtain.
CSE: How have dwindling school budgets affected your work?
Roy: This is the ultimate challenge. When we start a new project, one of the first questions for the client is what financial constraints are in place. Will the client consider long-term cost savings over upfront cost savings? Based on that, we can make appropriate design choices. Yates: School administrators have to make hard choices on their capital projects as well as with their operating budgets. One trend we have seen is an increased interest in automated two-pipe changeover systems. This lowers the first cost, operating cost, and maintenance cost, and still provides good occupant comfort. The building must have fairly consistent thermal loading for this to be a good choice, but it works well for many new and existing school buildings. Lighting controls and other energy-saving strategies are common as well. We have also seen an increased interest in existing building commissioning as a means of maximizing the available assets with minimal additional capital costs.
Linder: Reduced consultant fees are impacting construction document quality. We see details and specification information that was obviously copied from a previous project but not updated to reflect the current project. On the operations side, it is obvious that the O&M personnel do not have the time, or staff, to perform most maintenance tasks. They are lucky to keep up on the day-to-day needs.
CSE: How does the age of a school structure affect your ability to retrofit or retrocommission features?
Linder: Age is a huge factor. Older buildings generally do not meet ventilation requirements, but lack room for new ductwork and equipment. This has a major impact on design decisions. For example, unit ventilators provide an economic solution to increased ventilation and cooling capacity requirements. However, their use decentralizes maintenance, moving tasks to equipment in occupied spaces, and often results in HVAC-related noise issues.
Yates: Envelope issues are probably the biggest obstacle in retrofits and subsequent commissioning. Many envelope issues are extremely difficult to correct without a major renovation. The appeal of a simple retrofit is quick turnaround time and minimal loss of building usage, all at a reduced cost compared to a complete renovation. Minimizing energy use while designing mechanical systems that overcome envelope issues is a challenge. Commissioning activities must be expanded to identify and document unique problems that can arise due to the existing conditions. Some issues are difficult to identify prior to the acceptance phase, which makes them all the more difficult to solve.
Roy: The age of the school isn’t as much the determining factor as the available budget. Based on the project budget, any building can be retrofitted to achieve significant operational energy savings relative to the legacy systems.
CSE: What sorts of problems or faults do you encounter with existing HVAC systems at existing K-12 schools that you find your firm having to correct?
Linder: The most common issue we find is an overridden control system. Typically the operations staff has overridden setpoints and equipment schedules at a minimum, to satisfy building occupants. While they met their immediate goal, the long-term consequences have a major impact on energy use and overall system operations. Luckily, these items can be easily corrected.
Roy: Typically, we deal with systems that were never—or at best, poorly—commissioned. An average system that was properly commissioned and maintained can easily out-perform a building which may have received significant MEP upgrades but was not commissioned properly.
McFarlane: While the control sequences can be somewhat sophisticated, most building maintenance staffs are required to perform a multitude of janitorial services and maintain buildings and grounds. Staff is not given the training or the time to properly troubleshoot HVAC problems that are causing complaints. In order to quickly resolve a heating complaint, heating valves are shut, fresh air dampers are opened to lower the mixed air temperature, and airflow setpoints are increased or decreased based on the staff’s understanding of the problem. Change upon change is made without any engineered approach to solving the problem.
Yates: The most common problems are related to equipment that is broken or has reached the end of its service life. Often temporary measures have been taken to keep the equipment operational. Sometimes these “fixes” cause other problems. Many of these systems have pneumatic controls with minimal unoccupied controls. Some of the newer projects (less than 10 years old) have reasonably good equipment and BAS controls. However, with staff changes and inadequate orientation for the new staff members, much of the efficiency and value in these systems is lost. We find many systems in manual mode, others not working at all.
CSE: How do school projects differ by region, due to climate differences and the local AHJ?
Roy: Our exposure has primarily been in the local Chicago market. However, when we have designed a few building on the East Coast, our biggest challenges were to design with the correct weather tables and taking into account environmental considerations such as longer daylight hours further south and the different design considerations for hurricanes in coastal areas. That’s not a concern in Chicago.
CSE: How can automated features and remote system control benefit school clients?
Yates: Our clients have found remote access extremely valuable. The systems can be reset to accommodate the after-hours event that no one scheduled. Alarms can be reviewed and evaluated before sending the on-call technician or contractors. Holiday and school break schedules can be programmed in advance so that energy is not wasted, yet the building conditions are reset before the staff and students arrive on the next school day. It’s impossible to efficiently manage these things without a fully functional BAS.
Linder: Start with good controls training. Operators must be able to navigate the system and understand the nomenclature. When properly trained, the operators can use the system to operate the system efficiently and to diagnose problems. If the alarms that come to the building engineer are important, they will be less likely to ignore them and potentially critical situations can be averted. Remote access enhances all of these benefits.
CSE: What are the most important factors to consider when working on such a system?
Linder: First and foremost, ensure the system is properly commissioned. The entire system is useless if the information is not accurate. Operations staff will quickly lose faith in the system and all potential benefits will be lost. Even if commissioned at a later date, the initial distrust will linger for a long time. Secondly, train the staff. The impact a trained staff member has on building operation is critical to occupant comfort and energy efficiency.
Roy: The reliability of automated systems is critical. Sometimes, it is better to stick with slightly older but proven technology over the latest and greatest technology.
Yates: Temperature control contractors often do what they did on the most recent similar project, or use the standard program provided with their system. This approach often negates many of the designer’s energy-saving sequences, or worse yet, leads to early equipment failure. The systems should be relatively trouble-free, but they still only react as programmed.
CSE: What impact has the U.S. Green Building Council’s LEED for Schools had on lighting design?
Roy: Lighting design has been affected the most by the power density criteria in LEED, which is relatively standard across classifications. Specifically in LEED for Schools, the major difference is a specific requirement for the two illumination modes for classrooms; general and A/V. The second mode requires a slightly more complicated system that eliminates the “always on” emergency fixture(s) in lieu of fixtures that can sense loss of power and activate in an emergency. Good old-fashioned “bug lights” are always the easy, though less attractive, solution.
CSE: What’s your opinion of and experience with daylighting?
Linder: When designed properly, daylighting significantly enhances occupant satisfaction with their environment. When done poorly, people compensate by adding task lighting wherever possible. My advice is similar to selecting the mechanical system engineer: Make sure your project has a good lighting engineer on board.
Roy: We generally consider daylighting a valuable strategy for energy reduction. However, it must be coordinated and balanced with the fenestration choices of the architect and low-E properties for better heat transfer properties.
CSE: What changes/developments do you think are in the future for schools?
Linder: Lighting technology is rapidly advancing, for new systems and for retrofit applications. The energy use and environmental satisfaction related to lighting is just as important as the HVAC systems. This fact should not be overlooked.
Roy: We are still waiting for cost-effective LED lighting technologies to filter down to schools. Once color, LED quality and consistency, and cost are no longer constraints, it will enable more creative lighting solutions.