School is in session
With mitigating factors like aging structures, complex codes and standards, and emerging technologies, K-12 school projects can pose quite a test. Here, top consulting engineers share important lessons on what techniques and technologies will get you to the head of the class.
Participants (left to right):
Scott Gordon, PE, CxA, LEED AP BD+C
Associate Principal/Director of Commissioning
TMAD TAYLOR & GAINES
Michael J. Knoras, Jr., PE
Aon Risk Solutions
Michael P. Sherren, PE, LEED AP
James Posey Assocs.
Alfa Tech Consulting Enterprises
San Jose, Calif.
CSE: Please describe a recent K-12 school 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.
Scott Gordon: The most recent K-12 project that our team has been involved in was the Los Angeles Unified School Districts Robert F. Kennedy Community Schools. Currently the largest and most expensive K-12 school project in the country (approximately $578 million to construct), it is on the site of The Ambassador Hotel, the exact stop where Robert F. Kennedy was shot in 1968. Some the problems that occurred on this project were developing new designs, such as thermal displacement ventilation for the main auditorium; or daylight harvesting, while still being governed by older design criteria since the district’s design requirements have not updated to the latest energy-saving measures. The way we solved the issues was to educate the district design managers on new design concepts that would save the district money by including the latest designs for energy savings. Incorporating high-efficiency equipment in the design of the central plant, thermal displacement in all classrooms and large occupant areas, and daylight harvesting controls allowed the entire complex to have 24% energy reduction versus the latest California energy codes.
Michael P. Sherren: I recently completed the design of a 95,000-sq-ft elementary school located in Silver Spring, Md. The project had significant site constraints, impacting both the design team and construction manager. Construction staging areas and site access limitations required careful planning and consideration by the project team. Adding to the overall site complications was the ground-source geothermal heat pump unit system that was planned for the facility. The design team worked closely to maximize the energy efficiency of the building’s wall construction, glazing systems, and lighting system. In addition, the depth of the geothermal wells was increased 25% beyond previous projects, minimizing the site footprint required. By optimizing the building systems that influence the required capacity of the building’s mechanical system and minimizing the site footprint required to accommodate this system, the design team was able to deliver a facility that was constructible, within budget, and met the owner’s sustainability goals.
Reza Zare: Recently we designed an MEP system expansion in existing buildings. The challenge was keeping the HVAC system the same type and manufacturer so the district would not have two types of systems in the same school. The challenge was also bidding the HVAC in advance and then receiving the bid. Unfortunately, we did not get the same manufacturer we specified; the bid had to be cancelled and re-bid for the HVAC for the entire building. Finally, we achieved the bid with the same manufacturer.
CSE: What are the top three things school administrators are requesting in their K-12 school projects?
Zare: Most of the administrators are requesting the building to be LEED-certified or CHPS-certified lighting and lighting controls, and building automation.
Gordon: Many administrators are looking for ease of maintenance, equipment which is long-lasting but with low maintenance cost, and equipment which is vandal-proof.
CSE: When working on retrofits of existing buildings, what’s the No. 1 issue you encounter, and how do you resolve it?
Gordon: The No. 1 issue is to determine existing utilities, equipment capacities, and their conditions. Typically, we have to hire a contractor to assist in the investigation. In many conditions, we find that the proper solution is to replace the existing equipment with new, more energy-efficient equipment.
Sherren: When working on renovations or retrofits of existing buildings, physical fit can certainly be a challenging aspect. Many schools were initially designed with limited floor-to-floor heights. The mechanical systems that condition these facilities typically utilize unitary equipment with direct space ventilation. While these systems were adequate for space conditioning and ventilation when initially designed, they may not meet current thermal comfort, acoustical, and sustainable design standards. Overcoming this challenge involves a collaborative team effort, developing solutions that integrate the mechanical systems and the building architecture. Applying localized versus centralized mechanical systems, located within closet areas adjacent to classroom areas served, is one solution that has been utilized successfully for these projects.
Zare: Issues include attaining accurate record drawings by extensive field survey—sometimes a challenge in itself due to limited access to some of the areas—and video of the entire site, underground utility survey, and potholing around the building area where the utilities are connected.
CSE: What are some common problems you encounter when working on automation or control systems?
Zare: Verification of commissioning of the emergency management system. Most often the district will not hire third-party commissioning agents to commission the performance of the building.
Sherren: When designing building automation systems for any school facility, it is important to avoid overcomplicated designs. Developing control strategies that are simple and concise yields the best results. Control system problems can arise when the design engineer’s intent is not clearly communicated, or when the control system design becomes overcomplicated. Code algorithms developed by the programmer may not accurately reflect every detail of the design engineer’s intent. These gaps are common on any project and can typically be diagnosed and resolved during the later stages of the construction and commissioning process.
CSE: How can automated features and remote system control benefit school clients?
Zare: They can save time diagnosing the problem and have the capability of controlling and adjusting the control system.
Sherren: Network building automation systems allow for centralized monitoring of multiple school facilities. This feature is critical to many of the county school districts we work with throughout the Baltimore/DC area. Remote monitoring and system access allow energy management routines that can be standardized throughout all facilities, with the ability for remote adjustment by a single operator. Remote access and network control functions also allow instant communication of building alarm conditions to the appropriate school personnel.
CSE: How have recent changes to HVAC codes and standards affected your work on K-12 schools?
Sherren: Recent changes to the International Mechanical and Energy Conservation Codes have influenced the design of school facilities. The requirements for improved building and mechanical equipment efficiency have placed a greater focus on sustainability. The evolution in mechanical equipment technology and efficiency in response to these changes has been exponential over the past five years. Many owners are evaluating decisions from a lifecycle perspective rather than simply on first cost. In addition to improved energy efficiency, updated ventilation requirements have influenced the way we design many school projects. Limitations imposed by these codes on the recirculation of air for select classroom and laboratory areas require a different design solution than was typically applied previously for these areas.
CSE: Which codes/standards area proves to be most challenging in school work?
Michael J. Knoras: The most challenging requirements are normally not found in the adopted building codes but in separate legislation, laws, and standards created or adopted by the state. An example of state-generated requirements would be the State Requirements for Educational Facilities, once a separate state requirement and now incorporated in the Florida Building Code. It specifically calls out requirements for school buildings, portable classrooms, and other structures which may exceed the normal state building code requirements for an educational facility. Another challenge is when the state adopts codes and standards that conflict with one another, such as was found until the 2004 Edition of ANSI A17.1: Safety Code for Elevators and Escalators, and NFPA 72: National Fire Alarm and Signaling Code. The differences in these codes, and the fact that the elevators were normally inspected by state elevator inspectors while the fire alarm systems were inspected by local fire departments, led to many projects having last-minute additions of, or possibly even extraneous, equipment installed in an effort to satisfy both “authorities.” In many cases, you can be faced with attempting to design for all possible requirements, sometimes a much more costly venture, rather than risk missing the deadline for completion and occupancy of a building.
Gordon: We have found that the fire alarm and emergency lighting requirements of the current NFPA and NEC are the most challenging in school projects.
CSE: What’s the one factor most commonly overlooked in electrical systems at K-12 schools?
Zare: One factor is anticipating that for future expansions, the main electrical service is adequate.
Gordon: The most commonly item that is overlooked is the appropriate location and size of the main electrical room. Typically, architects are giving the electrical designers an area that is in the opposite end of the school and they want to minimize the size because they need the area as part of a classroom, teachers’ work area, etc., that makes the electrical room layout difficult. An undecided owner’s furnished items, that is, smart classroom work boards, tele/data connections, projectors, and electronic screens are very often overlooked since the school’s project manager is not sure of the equipment that the school will be supplied with because of budgets.
Sherren: During the early stages of a design, adjacencies and adequate space planning of electrical systems are often overlooked in favor of the other school program requirements. The architect fully addresses classroom adjacencies with respect to other specialty spaces, such as the media center or administrative suite. However, electrical and telecommunications closets often are squeezed, placed in remote areas, or equipment is located wherever space permits. This leads to inefficient distribution and consequently increased project cost. Dedicated electrical and IT spaces centralized around the loads served are ideal and generally obtainable when discussed early and incorporated into the initial conceptual layout.
CSE: How has the demand for efficient lighting and use of daylighting affected your work on school projects?
Gordon: The demand has increased our design efforts to coordinate the skylight locations with lighting fixtures and the controls.
Sherren: With many schools now seeking U.S. Green Building Council (USGBC) LEED certification and recognizing the energy-saving advantages of efficient system designs, there is a larger focus on optimizing the lighting system design. In the past, the engineer could focus mainly on proper illumination levels and fixture aesthetics. Now, the same engineer must develop a more comprehensive lighting solution—one that addresses reduced fixture wattage, occupancy-based control, multiple light levels/zones, daylight harvesting, etc. With the engineer tasked to achieve lower lighting power densities with varying illumination levels, light fixtures must be carefully selected to complement the lighting control strategy for the space.
Zare: Controls are now a much more important issue.
CSE: Describe a unique classroom design in which you used specialty lighting, controls, daylighting, etc.
Sherren: We have seen an increasing number of school projects introduce solar tubes into classrooms. Most classrooms share an exterior wall and have ample vertical glazing to allow in natural daylight. However, not all classrooms and learning spaces can be located along an exterior wall, although there is still a desire to bring natural daylight to theses spaces. With enough solar tubes, we are able to provide natural daylight into the classrooms, and in some cases have incorporated daylighting control of the classroom lighting fixtures. The solar tubes even offer additional daylight dimming options with integral switch-operated baffles.
Gordon: We are finding many schools are going to the smart classroom system, which utilizes the connection of the audio/video system which dims the lights when the audio/visual system is in use.
CSE: What changes in mass notification systems have you seen in K-12 schools recently? What do you see changing in the near future?
Gordon: Currently, most K-12 schools do not include mass notification systems in the design of the fire and life safety systems. We believe that this type of system should be included in the design of all K-12, colleges, and other educational facilities.
Knoras: Most schools have had a form of mass notification for decades by virtue of their campus-wide public address and telephony systems, which provide voice communication during both normal and emergency situations. In addition, there are fire alarm systems used for emergency evacuation, but these were usually horn- or bell-based and were useful only for evacuating a building, rendering them for the singular purpose of emptying a building. Not so long ago, it was very difficult to convince a school district to invest the extra money for a combination fire alarm/mass notification system with one-way voice communication, unless there was a code requirement (e.g., an atrium in a building, an assembly occupancy with 300 or more occupants, etc.). However, in the past several years there have been events on school campuses which have caused many school districts to reconsider having more robust (i.e., supervised) communication systems. Most notably, those situations where the fire alarm system has actually been used by someone to evacuate school buildings for the purpose of inflicting harm on the occupants once they have left the safety of the building. This has highlighted the need for more instructive communications to inform the occupants of the emergency and the appropriate action, which may be to stay where they are and await instructions. With the higher profile that mass notification has been given due to tragedies on college campuses, K-12 districts are seeing the value of providing a dual-purpose system by simply adding the voice component to a fire alarm system. With the overall cost increase to add voice to a fire alarm system far less than a separate, supervised mass notification system, we would expect to see more school districts embracing this combination system as the need for real-time emergency communications increases.
Zare: Mass notification is not a requirement at this time, but will be in the coming years. Many school districts require the public address system to function as their lockdown system, but ultimately the code will require the fire alarm system to take on this function.
CSE: How does public safety legislation such as the Jeanne Clery Act affect your work on such projects?
Gordon: This is very important public safety legislation which helps reduce crimes in schools. This will increase the scope of work for all schools by providing different security systems, including closed-circuit television and rescue assistant systems.
Zare: University projects all require “blue light” warning systems tied into the campus security/police station. Many campuses are installing security cameras throughout, although we have yet to work on a project where there is an active surveillance system (someone watching the camera 24/7). Many campuses are considering mass notification, but we have yet to design one. Many K-12 districts, especially in high-crime areas, are also installing surveillance systems.
Knoras: I can’t say there are any specific changes which affect our work with regards to life safety. This act originated in 1990, with several revisions over the years, and deals primarily with security issues and the distribution of information regarding the security issues in a given area for higher education facilities. They’ve expanded the scope to include documenting fire events, but anyone following the requirements of NFPA 72 should already be documenting these events, as well as any servicing/testing of their systems.
CSE: What are some important factors to consider when designing a fire and life safety system? What things often get overlooked?
Zare: Fire and life safety is so highly monitored and regulated that there are few regularly overlooked items. Smoke dampers can be an issue as these are generally designed near the end of the project and are a coordination issue. California requires all school to have fully automatic systems, so the designer needs to have a clear understanding of the three-dimensional nature of the building, where there are pockets, unusual ceiling conditions, deep structural beams, ceiling types, chases, etc.
Knoras: I think it is very important to revisit the basics when starting any new project—determine the objective of the design, identify the true hazards for the specific building or area, and effectively address the hazard. It can be very easy to default to the prescriptive solution for a fire alarm or fire suppression system, with little regard to the physical architecture, construction materials, or even the actual usage of the room, area, or building. In using this approach every time, and not simply a cookbook solution, we can also identify areas where we can effectively meet the life safety and property protection requirements and achieve cost savings.
Gordon: Some of the items that always needed to be considered when designing fire/life safety systems are the type of systems, physical items like beam pockets, total areas above ceilings, and locations of fire doors. System design aspects like the coverage of the smoke and heat detectors and the visual and audio devices, like horns/strobes and speakers, need to be coordinated with ceiling items, like lights and HVAC registers, and furniture. Many times all of the information about the owner-supplied furniture is not known during the design phase, and this makes it difficult for complete coordination.
CSE: Describe a recent project in which you included an emergency communication system—what was the project, and how did you design the system?
Knoras: The State of Florida requires each school campus to have an enhanced hurricane protection area, which is a designated building with special reinforcements and independent systems designed to function during a hurricane event. Again, a voice fire alarm system is used for emergency communications, although the capability is only required in that specific building. Historically, a voice system was treated similar to a non-voice system; you needed to meet the minimum sound pressure level required by code in all occupiable areas. You had to be certain an occupant could hear the message, but there was little concern as to whether the message was being understood. The newest challenge, although it has been in the codes for over 10 years, is to meet both the audibility (sound pressure) and intelligibility (quality of the voice message) requirements of NFPA 72. Now the message has to be heard and understood. What I have found to be the best approach when developing a design for an intelligible emergency communication system is to review the each room/area environment to determine if the sound produced will be more likely to be absorbed or reflected. Your design needs to be flexible enough to adjust for the final condition of the room or area, or even a future modification. An approach that is very effective is to provide more speakers, closer together, and at lower wattages. This provides a more uniform sound and the lower wattage helps to reduce reverberation which can seriously distort a message. It also affords the opportunity to make field adjustments to tailor the final intelligibility. There is nothing worse than designing a voice system with all the speakers at the maximum, or near maximum, wattage, needing more sound pressure (higher wattage), and finding you don’t have enough. Better to add more speakers as part of the original design than to have to break open a completed wall or ceiling just before your final inspection to add more.
CSE: What are some of the most notable engineering aspects of the USGBC’s LEED for Schools?
Gordon: Changing the attitudes of school officials is a long process. Many of the design managers know they require sustainability to be designed into their projects, but they do not understand what that means. They think that they can still have a low upfront cost project with many pieces of high-efficiency equipment and systems designed into their project. You have to educate each of the design managers to understand that there could be a larger upfront cost, but the school will save money in energy cost over time for a larger savings.
Sherren: The USGBC’s LEED for Schools rating system has brought the importance of quality engineering to the forefront. While building energy efficiency always has been an important engineering element, the LEED rating system has helped school officials recognize this factor and evaluate designs from both a lifecycle-cost and first-cost perspective. LEED for Schools has also been vital in emphasizing the importance of acoustical performance within core learning spaces. The design of mechanical systems has transitioned from the use of equipment located within the classroom space to the use of mechanical system components that are located outside core learning areas.
CSE: How have changing attitudes of public officials affected your work on school projects regarding sustainability?
Zare: The State of California (and other states) has made sustainability a huge focus, starting from the state architect and promoted throughout the system. Most school districts, both K-12 and community college, have mandated minimum levels of sustainability (LEED or CHPS). We are seeing on-site generation (solar and fuel cells) at a large percentage of school districts.
Sherren: Sustainability has become a priority for most school projects that our firm is directly involved with. Owners and public officials have recognized the importance of this element in the design of their facilities. Project decisions are being evaluated from both a lifecycle-cost and first-cost perspective, which is certainly a step in the right direction. Sustainability has also generated a greater importance level and overall interest in the engineering aspects of the building systems being designed.
CSE: Discuss a recent retrofit or retro-commissioning project. What were the challenges, and how did you overcome them?
Zare: Existing facilities limit the effectiveness of sustainable strategies due to orientation and space restrictions that do not encumber new buildings. This does not mean that great gains are unattainable.
CSE: Describe a recent project in which the school administration included the building’s energy efficiency aspects in its curriculum.
Zare: We have designed a couple of high school science buildings and a new college campus. As early as 2002, this district required these buildings not only to be highly sustainable, but also to incorporate the building design into the curriculum. Being science buildings, this made the building a living example. One specific design feature was locating the solar inverter in the corridor so students could watch the conversion of power directly on the digital readout on the unit. These buildings were the model that was duplicated by many California schools in the following years. Current projects usually incorporate dashboards located in public areas that show instantaneous and historical energy and water usage data, and links to online versions on the district/school website.
CSE: In your experience, which climate region is the most difficult to design for? What unique HVAC tools have you used in these schools?
Sherren: Most school facilities we design are located within the Baltimore/DC area. This climate region poses a challenge in managing the humidity levels experienced throughout the year. Mechanical systems that are only responsive to space temperature can result in elevated room humidity levels, resulting in potential long-term indoor air quality concerns. To ensure proper indoor humidity levels are maintained, mechanical systems that control both space temperature and humidity levels are utilized. In many applications, the outdoor air is decoupled from the space conditioning systems, dehumidified and conditioned through a separate mechanical system such as an energy recovery unit, and delivered directly to the space at a room neutral temperature.
CSE: What are the most important factors to consider when working on school HVAC systems?
Zare: It is important to consider the right type of HVAC with ease of access for maintenance and future replacement.
Sherren: Solutions that incorporate simple, low-maintenance systems that provide both reliable and energy-efficient operation are paramount when designing any school’s mechanical system. It is important to consider the technical understanding of the facility personnel who will ultimately operate and maintain the systems being provided. Improper operation and maintenance of mechanical system components due to an overcomplicated design or failure to properly access system components will result in premature equipment failure and increased building energy consumption. Incorporating sustainable design concepts, such as enhanced building envelopes and reduced lighting power densities, offers low-maintenance solutions that reduce the initial size of the building mechanical system and improve the energy efficiency of the facility.
CSE: What impact has the USGBC’s LEED for Schools had on lighting design?
Gordon: LEED requirements typically ask for 20% to 25% lighting reduction over the energy model. For California, that energy model is the baseline model in accordance with the California Energy Code (Title-24).This additional requirement typically adds lighting controls, which adds costs to the overall project.
Sherren: LEED for Schools has greatly impacted school lighting design in recent years. We continue to search for creative ways to reduce lighting power density, incorporate cost-effective lighting and daylighting control, and eliminate light pollution while still maintaining good lighting performance. School systems have had to find a balance between providing a simple, maintainable lighting system and embracing the recent technological advancements in lamping and lighting controls.
Zare: Increased budget and increased usage of automatic controls, including time management control panels, occupancy sensors, and daylighting controls.
CSE: When adding daylighting to your design, what products or techniques do you use? What has been the response?
Zare: Depending on the complexity of the building and design, we have used everything from simple experience-based rules of thumb to very complex daylight modeling. The best modeling software is Radiance, which is quite accurate but not well documented. Daylighting includes working with building geometry and orientation, designing optimum fenestration, shade/glare control, and electric lighting controls. Fenestration can involve skylights, side lights, clerestories, monitors, light shelves, etc., and must be designed to maximize light penetration while minimizing heat gain/loss. In addition, normally one designs daylighting to avoid direct sunlight penetration. There are several options for designing electric lighting controls, all of which involve photocells. SPOT is easy-to-use software to determine optimum location and aiming of photocells, without which the system will not function properly.
Gordon: We have used daylight sensors or daylight harvesting, or a continual dimming system, as a technique when adding daylighting to the design. Most clients consider daylight harvesting as the best possible response to energy reduction, while still allowing prior lighting in the specific area.
CSE: Describe your experience with lighting sensors and controls in K-12 schools.
Zare: Lighting controls in schools need to be intuitive as you simply cannot train every user in how to program complicated controls. That said, the most energy-efficient control systems include occupancy sensors and photocells. There are products available today that provide both of these functions in one device, along with the control logic. They are easy for contractors to install and even easier for users as they are totally automatic. The only thing the user needs to do is turn off the wall switch to darken the room for presentations. The Finelite ICLS system was designed under a California PIER grant to develop the ultimate educational lighting control system. The lighting for a typical room arrives at the job site in a single package—fixtures, plug-and-play controls, and wiring. The lighting is top-of-the-line energy-efficient, and the controls include a presentation option that turns off the whiteboard light fixture while allowing lighting on the desks for note taking. The system has been a great success for us, except whenever we have tried to modify/customize the controls.
Gordon: On previous projects, we have used Dali and Lutron Ecko systems for lighting controls. These systems typically are easy to install but can be difficult to get all of the programming correct. During the final checkout, or commissioning process, when all of the lighting controls are verified, it is typically determined that some of the lighting sequences need adjustment, but many of the systems are proprietary and the installers need a LAN or phone line to reprogram the system, which causes delays in the final checkout.