Manufacturers' focus: Designing K-12 schools
Engineering work on K-12 schools is complex. Here are insights from manufacturers who provide products, equipment, and solutions.
- Scott Laurila, Product Manager, Greenheck Fan Corp., Schofield, Wis.
- Rodger Reiswig, Director of Industry Relations, SimplexGrinnell, Orlando, Fla.
CSE: What trends are you seeing in K-12 schools?
Scott Laurila, Greenheck: Engineers and designers are shifting more ventilation system designs from variable volume rooftop systems to dedicated outdoor air systems (DOAS). By decoupling sensible and latent loads, a DOAS can accurately control both humidity and temperature in an energy-efficient manner at both full- and part-load conditions. Also, with rising energy costs, tighter construction and operating budgets, and growing requirements in energy standards such as ASHRAE 90.1-2010, air-to-air energy recovery ventilation is becoming a necessity in school designs.
Rodger Reiswig, SimplexGrinnell: K-12 school applications for intercom, telephone, Internet protocol (IP) communications, etc., have merged into either a single system or multiple systems sharing a backbone or IP highway. This has allowed for K-12 applications to use, for example, an IP speaker that can provide for class-change tones and announcements and convey mass notification and other life safety instructions and information.
CSE: What's the most important advice you could offer an engineer considering your product for a K-12 school project?
SimplexGrinnell: The concept of merging or integrating the general intercom and alerting systems into a single platform is growing. Consideration needs to be given regarding how the system will be used or how one anticipates the system may be used during an emergency. It’s important to understand that the application of technology is only part of the final solution. How the equipment will be used during either daily normal events or emergency situations becomes a key point during design. To help the industry with this, the National Electrical Manufacturers Association (NEMA) has published SB 40-2008 Communications Systems for Life Safety in Schools. This guide covers the application, installation, location, performance, and maintenance of school communications systems and their components. It establishes guidelines for levels of performance, extent of redundancy, and quality of installation.
Greenheck: It’s important to take advantage of the heating and cooling reduction associated with air-to-air energy recovery. Oversizing cooling and heating systems not only adds to first cost, but also is a detriment to system performance and control. Additionally, energy codes such as the 2012 International Energy Conservation Code do not allow oversizing equipment when energy recovery is applied.
CSE: What factors do engineers on such projects sometimes overlook?
SimplexGrinnell: Periodically designers of systems only view how the system will be used during routine announcements and daily activities. What sometimes gets overlooked is the fact that these systems will be relied upon to disseminate information and become incorporated into the Emergency Response Plan of a facility. The NFPA has just released its latest edition of NFPA 72: National Fire Alarm and Signaling Code. Within the 2013 edition of NFPA 72, there is great information to help a designer apply not just technology, but also how the technology should be used efficiently and how it might integrate with the fire alarm system. Chapter 24 of the NFPA 72 document contains information on performing a “risk analysis,” assisting with the creation of an “emergency response plan,” and using both to create a total solution for the K-12 environment. By using both the NEMA SB 40 and NFPA 72-2013 documents, a designer can gain a good understanding of how to create a total concept solution using technologies as well as understanding how a system will be used.
Greenheck: System-level control is always an important consideration for a design engineer, but manufacturers have made significant advancements in unitary controls. Understanding how a manufacturer’s tested and proven control sequences can fit into system level design provides owners and end users with the most reliable outcome.
CSE: Regarding automation and controls, system integration in K-12 schools is becoming more prevalent. How is your company/product meeting this need?
Greenheck: Engineers, controls contractors, mechanical contractors, and manufacturers all have a stake in providing robust controls systems, so the coordination of controls and system integration is always a challenge due to the number of parties involved. As a manufacturer, it is very important to offer engineers configurable, pre-engineered control solutions that minimize the time to project completion. On unitary direct digital control (DDC) platforms, incorporating features like LCD interfaces and open protocols facilitates start-up, integration, and commissioning.
CSE: How does your technology help engineers make their clients’ K-12 school structures more energy efficient?
Greenheck: In ventilation systems, there’s no better way of reducing energy consumption than by incorporating air-to-air energy recovery. Energy recovery reduces energy consumption and operating costs by capturing cooling and heating energy before it leaves the HVAC system. In applications such as a DOAS, the size of the cooling and heating system in the outdoor air equipment can be reduced by 50%, which saves considerably on operating costs as well as system first costs. Energy recovery can also be applied in VAV units or operate as a stand-alone pre-conditioner, which gives engineers the opportunity to incorporate an efficient technology regardless of system design preference.
CSE: What HVAC challenge (humidification, indoor air quality, building envelope, etc.) comes to the forefront most frequently when you’re supporting engineers working in K-12 schools? How do you help overcome these issues/answer their questions?
Greenheck: Controlling humidity in the cooling season at both full- and part-load conditions is at the forefront of most engineers’ minds in K-12 projects. Air-to-air energy recovery is a great way to control humidity as it preconditions and dehumidifies the air entering cooling coils. In air-cooled systems, incorporating variable capacity compressors and modulating hot gas reheat improve supply air dew points and improve space comfort. Finally, the ability to reset target supply air dew points through unitary controls can provide further assurance that the outdoor air equipment will perform as ambient conditions vary.
CSE: What new mass notification or emergency communication system has been the most successful? Describe a recent project.
SimplexGrinnell: When it comes to emergency communications, K-12 schools face complex challenges, yet one thing is clear: In today’s world, no one technology can provide a complete solution. The best approach is to deploy multiple layers of technology to disseminate critical information to the people and audiences who need to be reached in an emergency. A multi-technology approach to emergency communications can combine voice communications, visual messaging, and wireless personal notification capabilities into an integrated solution that provides the means to effectively communicate with all constituencies during an emergency. Interior voice systems driven by today’s advanced fire alarm networks, and possessing built-in survivability, can instantly broadcast live or recorded messages throughout any institutional setting. A universal message, or an individual message tailored to a specific area, building, floor, or room, can be delivered through such a voice-enabled fire alarm system. It can provide immediate communications that can also be modified to match changing emergency conditions. A voice-enabled fire alarm system can be supplemented by large outdoor speaker systems capable of broadcasting real-time warnings and instructions to exterior gathering spots, off-site buildings, and satellite properties.