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Remote Testing Module

A Simple, Cost Effective Damper Test Method

Belimo’s FSKN remote inspection module allows testing of actuated life safety dampers without the need for costly visual inspections, and it meets testing requirements of NFPA 80 and NFPA 105 referenced by the International Building Code (IBC).

The module initiates damper cycling and verifies the damper position to ensure proper operation in emergencies. The FSKN connects seamlessly to Fire Alarm panels or Building Automation Systems using BACnet or Modbus communication protocols.

NEWS &BUSINESS

5 | How can energy goals, refrigerants stimulate HVAC engineers?

Mechanical engineers are pushed by energy efficiency and refrigerant updates.

BUILDING SOLUTIONS

6 | How to use ASHRAE 90.1 to boost the power of commissioning

Newer energy codes and standards are changing the landscape for designers, contractors and owners.

12 | Know how to navigate compliance paths of ASHRAE Standard 90.1

The shift to energy efficiency requires engineers and designers to be proficient in updates to ASHRAE Standard 90.1-2022.

18 | Why and how to adopt the IECC for energy-efficient designs

Understanding the IECC can help engineers interpret codes and standards appropriately.

BUILDING SOLUTIONS

22 | Documentation revisions in the 2025 NFPA 72 code

Updates to NFPA 72 introduce changes to definitions and documentation to enhance clarity and reliability.

28 | Do you know the requirements for emergency lighting systems?

Emergency lighting requirements derive from provisions of various building codes.

34 | Back to basics: Microgrids and renewable energy

Microgrids can help system owners meet the special considerations necessary to integrate intermittent renewable power sources into power systems.

ENGINEERING INSIGHTS

42 | Focus on nontraditional learning spaces in K-12 building design

K-12 school buildings often seek more flexibility to provide unique learning paths.

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contained herein, regardless of whether such errors result from negligence, accident or any other cause whatsoever.

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AMARA ROZGUS, Editor-in-Chief ARozgus@WTWHMedia.com

ANNA STEINGRUBER, Associate Editor ASteingruber@WTWHMedia.com

AMANDA PELLICCIONE, Marketing Research Manager APelliccione@WTWHMedia.com

MICHAEL SMITH, Art Director MSmith@WTWHMedia.com

EDITORIAL ADVISORY BOARD

DARREN BRUCE, PE, LEED AP BD+C, Director of Strategic Planning, Mid-Atlantic Region, NV5, Arlington, Va.

MICHAEL CHOW, PE, CEM, CXA, LEED AP BD+C, Principal, Metro CD Engineering LLC, Columbus, Ohio

CINDY COGIL, PE, FASHRAE, Vice President, SmithGroup, Chicago

TOM DIVINE, PE, Senior Electrical Engineer, Johnston, LLC, Houston

CORY DUGGIN, PE, LEED AP BD+C, BEMP, Energy Modeling Wizard, TLC Engineering Solutions, Brentwood, Tenn.

ROBERT J. GARRA JR., PE, CDT, Vice President, Electrical Engineer, CannonDesign, Grand Island, N.Y.

JASON GERKE, PE, LEED AP BD+C, CXA, Senior Design Phase Manager, JP Cullen, Milwaukee

JOSHUA D. GREENE, PE, Associate Principal, Simpson Gumpertz & Heger, Waltham, Mass.

RAYMOND GRILL, PE, FSFPE, LEED AP, Principal, Ray Grill Consulting, PLLC, Clifton, Va.

DANNA JENSEN, PE, LEED AP BD+C, Principal, Certus, Carrollton, Texas

WILLIAM KOFFEL, PE, FSFPE, President, Koffel Associates Inc., Columbia, Md.

WILLIAM KOSIK, PE, CEM, LEGACY LEED AP BD+C, Lead Senior Mechanical Engineer, kW Mission Critical Engineering, Milwaukee

KENNETH KUTSMEDA, PE, LEED AP, Engineering Manager, Jacobs, Philadelphia

DAVID LOWREY, Chief Fire Marshal, Boulder (Colo.) Fire Rescue

JASON MAJERUS, PE, CEM, LEED AP, Principal, DLR Group, Cleveland

JUSTIN MILNE, PE, PMP, Senior Engineer, Southcentral Region, Jensen Hughes, Allen, Texas

GREGORY QUINN, PE, NCEES, LEED AP, Principal, Health Care Market Leader, Affiliated Engineers Inc., Madison, Wis.

CRAIG ROBERTS, CEM, Account Executive, National Technical Services, McKinstry, Powell, Tenn.

SUNONDO ROY, PE, LEED AP, Director, Design Group, Romeoville, Ill.

JONATHAN SAJDAK, PE, Senior Associate/Fire Protection Engineer, Page, Houston

RANDY SCHRECENGOST, PE, CEM, Austin Operations Group Manager/Senior Mechanical Engineer, Stanley Consultants, Austin, Texas

MATT SHORT, PE, Project Manager/Mechanical Engineer, Smith Seckman Reid, Houston

MARIO VECCHIARELLO, PE, CEM, GBE, Senior Vice President, CDM Smith Inc., Boston

RICHARD VEDVIK, PE, Senior Electrical Engineer and Acoustics Engineer, IMEG Corp., Rock Island, Ill.

TOBY WHITE, PE, LEED AP, Associate, Boston Fire & Life Safety Leader, Arup, Boston

APRIL WOODS, PE, LEED AP BD+C, Vice President, WSP USA, Orlando, Fla.

JOHN YOON, PE, LEED AP ID+C, Lead Electrical Engineer, McGuire Engineers Inc., Chicago

How can efficiency, refrigerants stimulate HVAC engineers?

Mechanical engineers are pushed by energy efficiency requirements and refrigerant updates.

The AHR Expo 2025 convened mechanical engineers and other building professionals to explore the latest innovations and regulatory developments shaping the built environment with a specific focus on heating, ventilation and air conditioning (HVAC) systems. While sustainability and energy efficiency remained central themes, this year’s discussions carried a heightened sense of urgency. With new refrigerant regulations taking effect as of Jan. 1, 2025 and industry uncertainty stemming from recent government workforce reductions, engineers must rapidly adjust to evolving regulatory frameworks.

align with international sustainability goals. While these changes promise long-term environmental benefits, they also pose immediate challenges, including the retrofitting of existing infrastructure, ensuring material compatibility and managing financial implications for building owners.

Sustainability is no longer a peripheral consideration — it is a fundamental driver of modern system design in commercial buildings. Manufacturers at the expo showcased advancements such as high-efficiency heat pumps and sophisticated building automation systems aimed at optimizing energy consumption without compromising performance. Engineers must evaluate these innovations through a multidimensional lens that considers cost, reliability and regulatory compliance.

A major focal point of the expo was the transition to new refrigerant standards, which are now in full effect. These updated requirements mandate the use of lower-global warming potential refrigerants to

Energy efficiency remains an industry imperative, particularly within data centers, where cooling requirements are increasingly complex. The expo highlighted advanced thermal management strategies, including liquid cooling and other high-performance solutions that cater to the escalating demands of data-intensive operations. Building controls also bubbled to the top of several conversations. Engineers must proactively integrate these emerging technologies while maintaining alignment with evolving efficiency benchmarks.

The ASHRAE Winter Conference, held concurrently with the expo, underscored the necessity of continuous engagement with industry developments. Whether addressing refrigerant transitions, decarbonization strategies or evolving energy efficiency mandates, a key takeaway was evident: mechanical and plumbing engineers must remain vigilant in tracking regulatory shifts and championing pragmatic, implementable design solutions.

Amara Rozgus, Editor-in-Chief

Anthony Montez, PE, CxA, DLR Group, Minneapolis

How to use ASHRAE 90.1 to boost the power of commissioning

Newer energy codes and standards are changing the landscape for designers, contractors and owners. It is imperative to effectively test and commission a project.

The commissioning process in recent years has evolved into a comprehensive quality assurance process that plays a critical role throughout commercial building design, construction and post-occupancy phases, especially as new ASHRAE Standard 90.1: Energy Standard for Buildings Except Low-Rise Residential Buildings (2019 and 2022 editions) requirements set higher energy efficiency standards.

Think of it as test-driving a car — not just to ensure it runs, but to verify it delivers on its promised performance, comfort and safety. Commis-

ASHRAE 90.1 Commissioning deliverables and requirements

1: ASHRAE 90.1-2019 commissioning requirements now include deliverables during the design phase. Courtesy: DLR Group

sioning can no longer just be about functional testing at the end of the construction phase. It now involves collaborating with the owner and design team early and often aligning the building systems with energy goals, identifying potential inefficiencies and ensuring compliance with the new energy code requirements. This proactive approach ensures the building operates as intended from the start, offering long-term benefits to owners and occupants alike.

ASHRAE 90.1 commissioning requirements

ASHRAE 90.1-2019 introduced expanded commissioning requirements to ensure compliance with the increase in energy-efficiency standards. The typical systems to be commissioned are still there: heating, ventilation and air conditioning (HVAC) systems; service water heating systems; and lighting controls.

However, starting with the 2019 edition of ASHRAE 90.1, new systems were introduced that have not been required before. These systems include electrical energy monitoring, whole-building energy monitoring and building envelope testing and verification.

When it comes to ASHRAE 90.1-2022, there are no new commissioning requirements compared with the 2019 edition. The 2022 edition reorganizes the content and refines the commissioning requirements to allow more clarity. For the sake of this article, the topic of discussion focuses on 2019 edition of ASHRAE 90.1, as it is starting to become the standard energy code adopted by many jurisdictions.

ASHRAE 90.1-2019 expands on the commissioning scope from previous editions by detailing

FIGURE

‘ASHRAE 90.1-2019

expands on the commissioning scope from previous editions by detailing specific requirements starting at the design phase through the postoccupancy phase. ’

specific requirements starting at the design phase through the post-occupancy phase. The purpose of the commissioning process is to provide a systematic approach to identify and correct deficiencies before the building is fully operational, helping owners achieve their energy performance goals. That cannot be completed effectively unless there is early integration. A terminology misnomer is that “commissioning” is functional testing. Those involved in the industry must understand there is more to commissioning than just functional testing to help move the needle as it relates to energy efficiency. These new commissioning requirements help speak to that commitment.

The commissioning provider’s role

These new requirements result in additional scope and cost that building owners, designers and contractors may not have previously accounted for. Given the relative novelty of these updates, stakeholders face a learning curve in adapting to the standard’s new demands. It is important for the commissioning provider (CxP) to walk through their process early and often on a given project to understand the benefits of implementing these changes effectively as it will result in cost savings and fewer headaches in the long run if commissioning is engaged and performed properly.

Two of the additional commissioning requirements that need to be included are electrical energy monitoring (metering of electrical consumption within the building such as HVAC and lighting systems) and whole-building energy monitoring (metering of utilities to the building produced by a central plant or utility provider such as chilled water and natural gas).

It is important for designers and owners to understand what metering equipment needs to be provided and where. Some common issues with metering equipment are:

• It is unclear who is to provide and install the meter.

• They are not shown in the right location.

• The meter polling frequency does not align with the building automation system (BAS) needs, resulting in incomplete data.

Scheduling a temperature controls meeting with the design team and contractor during the pre-construction phase can help flesh out these controls details along with other controls utility and energy

u

Objectives

• Learn about the value of commissioning from design through construction to follow through on energy goals.

• Know what to expect from the commissioning provider (CxP).

• Gain some best practices for long-term building performance.

FIGURE 2: Active involvement from the owner and facility operators in the commissioning process leads to improved long-term maintenance. Courtesy: DLR Group

BUILDING SOLUTIONS

Estimated new construction commissioning costs

monitoring related questions before procurement and submittal review.

Who performs the testing?

Building envelope is probably the most significant requirement introduced in ASHRAE 90.12019 that all parties must be cognizant of as it can result in higher costs if looped in later in the project. There are two paths to satisfy the building envelope verification requirements:

• Building pressurization testing per Section 5.4.3.1.1.

• Continuous air barrier design and verification per Section 5.9.1.2.

Building pressurization testing has gained traction since the early 2000s with the introduction of U.S. Green Building Council LEED and the option for additional credits. However, testing and verification has only recently become a requirement for projects greater than 10,000 square feet with the introduction of ASHRAE 90.1-2019. It is straightforward to understand the less leakage a building

has, the more energy efficient the building will be. In addition, codes are now requiring testing with growing emphasis on verifying building performance versus prescriptive only requirements. Understanding how this affects a given project should be a topic of discussion early in the design process.

As it relates to the option of pressurization testing, ASHRAE 90.1 lists multiple ASTM standards for testing providers to follow. This is key when it comes to the building enclosure specification development because this will allow the contractor to provide better bids for this test. If there is a construction manager on board, then they should also be looped into these conversations early so that no one is caught off guard later in the project.

It is also important to understand who can perform this testing. ASHRAE 90.1 states:

“Verification and testing providers shall be owner’s qualified employees, CxPs, design professionals, qualified designers or qualified technicians experienced with verification or functional performance testing of the designated systems.”

It is not entirely specific because the goal here is to allow for flexibility as it is up to the design team and CxP to discuss what is best for their given project. Again, it is key for the specification to clearly state that the testing agency has the necessary certifications along with documented experience with the listed ASTM standards and projects of similar scope and complexity.

The second option to satisfy the building envelope verification requirements is exception three to Section 5.4.3.1.1 that allows the project to bypass the building pressurization testing through verification of the design and installation of the continuous air barrier. To satisfy this requirement, a design review must be performed, followed by periodic field inspections of the air barrier and the reporting of any deficiencies. An advantage to the exception option is that experience with air leakage testing is not required by the testing provider, which can open the field of qualified providers to perform this service to many — even the CxP.

The goals and requirements for every project are different and conversations should be had to determine the best path forward. Exception three seems to be the more straightforward option and advantageous if schedule and construction costs are a top concern.

FIGURE 3: Commissioning costs vary based on project size and complexity, but they tend to plateau due to economies of scale. Courtesy: DLR Group

‘The goals and requirements for every project are different and conversations should be had to determine the best path forward. ’

To perform the pressurization testing, construction will likely have to be shut down for an extended period to allow for proper measurement to take place. This leads to additional coordination and effort with all the trades on the job. And if the test measurements fail to meet the given leakage requirements, then the pressurization testing will have to be performed all over again. That is not a concern with the exception three option. However, one might not necessarily have the peace of mind that their building is below the leakage requirements. These are just a few of the conversations that the CxP should be leading to understand what the available options are and who can perform these tasks to provide the best solution for the owner.

Commissioning and testing

As ASHRAE 90.1 is now requiring commissioning activities and deliverables during the design phase, early integration of the CxP is needed to satisfy the activities and certain deliverables during the design phase, which warrants early integration of the CxP these requirements. The documentation to expect from the CxP includes:

• Commissioning plan

• Commissioning design review comments

• Construction commissioning requirements (detailed in the specifications).

ASHRAE 90.1 Section 4.2.5.2.1 states that the above-mentioned information is to be included in the building permit application. The local authority having jurisdiction (AHJ) has final say what is necessary for a building permit, and it is important to understand that early integration of the CxP is critical for the project and to have the CxP identified early in the design phase.

The functional performance testing (FPT) period is the process that most built environment professionals probably associate with the commissioning process, where the CxP verifies equipment, assemblies and systems meet the defined performance criteria. Unfortunately on many projects, FPT doesn’t begin until the end of the construction phase and sometimes FPT takes place during the occupancy period, specifically for fast-track projects with short construction schedules such as educational buildings that tend to have “summer slam” construction projects.

ASHRAE 90.1 is now requiring an initial round of FPT along with a preliminary commissioning report to be completed before building occupancy. Again, this is up to the AHJ to enforce, but the push here is for testing during occupancy should be the exception. This aims to streamline the building handover process to the owner because it becomes much more difficult to functionally test equipment when there are manual overrides to allow facilities personnel to maintain a comfortable building while construction work is wrapping up.

A good amount of this information may be new to many. The key takeaway is to involve the CxP

FIGURE 4: Periodic field inspections of the building envelope are becoming more prevalent per ASHRAE 90.1-2019 commissioning requirements. Courtesy: DLR Group

BUILDING SOLUTIONS

5: Commissioning is starting to integrate systems beyond mechanical, electrical and plumbing engineering, and taking a wholistic approach on total building performance. Courtesy: DLR Group

early in the design phase. This allows the CxP to lead and assist with these discussions by identifying potential issues or hurdles as they relate to new testing requirements and recommending adjustments to meet performance and efficiency goals from the start.

Budget constraints: Commissioning can be perceived as an unnecessary expense at the design phase, especially if the project's budget is tight. As a result, commissioning services are sometimes cut or deferred to later stages, where it becomes more challenging to address design issues.

Role clarity and responsibility: When CxP roles aren't well defined, confusion arises around who is responsible for implementing commissioning recommendations. The design team might also be uncertain about how to collaborate effectively with the commissioning team.

Resistance to change in workflow: Design teams may be accustomed to a certain workflow and may resist adapting to one that includes commissioning input from the beginning. Adding additional steps or checkpoints may be seen as disrupting established processes.

Players in commissioning

csemag.com

Commissioning insights

u Building commissioning ensures that a building’s systems operate as intended by verifying their design, installation and functionality align with project requirements and energy efficiency goals.

u Codes and standards, such as ASHRAE 90.1, influence the design by mandating efficiency benchmarks and integration of systems like building automation, which commissioning verifies to meet performance criteria and compliance.

Early engagement enables the CxP to work with the design team to establish clear, achievable criteria for system performance, preventing costly design changes or delays during construction. By setting a foundation for collaboration early, the CxP can help guide the project toward a more streamlined efficient design-build process.

Why commissioning matters

There are some common pain points experienced during the commissioning process for a given project. With the introduction of performance-based standards, it is becoming important to recognize these hurdles and understand how the commissioning process can help deliver a better project. Some of these roadblocks include:

Lack of awareness or buy-in: Project stakeholders, including owners, architects and engineers, may not fully understand the benefits of commissioning or may see it as an added cost rather than an investment. This can lead to pushbacks against incorporating commissioning early.

The sentiment about the commissioning process is, at times, it is treated more as a box-checking exercise rather than a quality assurance tool that delivers important value to the entire team. It largely falls on the CxP to take the lead and facilitate team participation. A key to achieving this is ensuring that every team member understands how the commissioning process benefits them.

Designer: A designer would benefit as it allows them to verify that their designs function as intended and meet performance requirements in real-world conditions. Additionally, commissioning offers valuable insights into potential design improvements and fosters collaboration with contractors and facility operators, leading to more efficient and reliable building systems.

Building owner: A building owner’s participation ensures the facility will operate as intended, aligning with their performance and energy goals. Active engagement in commissioning helps owners gain a deeper understanding of their building systems, allowing them to improve long-term maintenance, enhance occupant satisfaction and reduce unexpected operational costs.

Facility operators: Facility operators benefit by gaining firsthand knowledge of the building’s systems, controls and performance requirements, which equips them to operate and maintain systems effectively from Day One. Their involvement

FIGURE

allows them to address any operational concerns early on, fostering a smoother handover once the building is fully operational.

Contractors: Contractors can ensure that their installations are correctly implemented and meet the project’s performance specifications, reducing the risk of rework and costly delays. This involvement fosters better communication with the design team and owners, enabling them to clarify expectations and resolve issues proactively, leading to a smoother project closeout and improved client satisfaction.

Active participation by all parties in the commissioning process creates a collaborative environment where design, construction and operational needs are aligned, ensuring the building performs as expected. This teamwork reduces misunderstandings, minimizes costly corrections and leads to a smoother project handover, ultimately delivering an efficient building that meets the owner’s goals and enhances occupant satisfaction — a winwin for everyone involved.

Once the value of commissioning is understood and there is active participation from the team, then additional benefits can be realized. A study conducted by members of Lawrence Berkeley National Laboratory and Building Commissioning Association that reports the commissioning costs and savings across representing 373 million square feet spanning three decades. Per that study, existing building commissioning projects resulted in 6.4% energy savings, a median payback of 1.7 years and a median project cost of $0.26 per square foot.

New construction commissioning projects resulted in 13% energy savings, a median payback of 4.2 years and a median project cost of $1.03 per square foot. Although the savings and value are evident, the value can be sometimes hard to grasp as these savings and efficiencies are somewhat overlooked as design-build professionals tend to focus on construction issues to ensure the project keeps moving forward. Whereas if a CxP was involved early in the design, then ideally that given project would have fewer requests for information, fewer change orders and less finger-pointing.

Creating the commissioning plan

In summary, ASHRAE 90.1-2019 is being adopted as the standard energy code in many jurisdic-

‘Once the value of commissioning is understood and there is active participation from the team, then additional benefits can be realized.’

tions. Designers, owners and contractors must understand how its updated commissioning requirements impact their work. Key changes include:

• Early commissioning integration: Commissioning activities and documentation are now required during the design phase.

• Preliminary commissioning report before occupancy: A first round of FPT and a preliminary commissioning report must be completed before the building is occupied.

• Expanded scope: Commissioning requirements beyond HVAC include building enclosure and utility and energy monitoring.

• Increasing AHJ oversight: While enforcement is still up to the AHJ, the new standard encourages stricter adherence to the commissioning process.

Ideally, the CxP should serve as a bridge between the owner and the design team by translating technical topics, design strategies and operational needs across all project stakeholders. With a background in engineering, construction or facility operations, a CxP should possess the technical expertise to understand design complexities and the practical experience to anticipate operational challenges. This unique skill set allows for effective communication with both the design team — speaking their technical language — and the owner, who may focus on long-term performance, cost-efficiency and usability.

Active participation and early integration from all stakeholders are critical to commissioning’s success. When stakeholders embrace their roles in the commissioning process and define goals early, they contribute to a building that is not only high-performing but also adaptable to future needs, ensuring long-term sustainability and operational excellence. cse

Anthony Montez, PE, CxA, is the National Commissioning Leader at DLR Group and has worked in the built environment industry for over 10 years.

Patrick Ryan, PE, CEM, Dewberry, Peoria, Illinois

Know how to navigate compliance paths of ASHRAE Standard 90.1

The shift toward energy efficiency will require engineers and designers to become proficient in the updated methods and requirements contained within ASHRAE Standard 90.1-2022.

While the 2022 version of ASHRAE Standard 90.1: Energy Standard for Buildings Except Low-Rise Residential Buildings has been available for three years, no states have adopted or referenced it as a statewide energy code, although that is changing in 2025. As a result, few within the architecture, engineering and construction industry have experience applying the latest compliance methods, such as the additional energy requirements required by Section 11 or the new mechanical system performance rating (MSPR) method outlined in Appendix L.

Many engineers, designers, architects, contractors and clients struggle to keep up with evolving energy codes and standards. Even senior engineers with decades of experience applying prescriptive requirements can find themselves behind. Because energy efficiency requirements have changed so significantly in the last few code cycles, engineers often struggle to find colleagues with tacit knowledge of the nuances found in these standards.

The need for a decision-making algorithm

Because ASHRAE Standard 90 was first published in 1975, the complexity of the standard has increased significantly. Figure 1 attempts to illustrate this by showing the number of pages per edition of ASHRAE 90.1, as well as Standards 90.2 and 90.4, which were originally under the umbrella of Standards 90 and later 90.1.

Recent code cycles have seen the inclusion of the Performance Rating Method — often known by its location within the standard, Appendix G — as a compliance path, the introduction of energy credit requirements and a new performance-based alternative for heating, ventilation and air conditioning (HVAC) system compliance within the overall prescriptive path.

FIGURE 1: This representation outlines the significant additions made to the ASHRAE 90 editions over the years. Courtesy: Dewberry

Objectives Learningu

• Be able to identify the various compliance paths and subpaths within ASHRAE Standard 90.1.

• Learn what is required for the performance-based compliance options.

• Develop a decision-making algorithm to choose which path to follow.

As energy standards become more complex, building owners and design teams will increasingly lean on the mechanical and electrical disciplines for advice on how to comply with the requirements. In the absence of intuition developed after many years of experience, a roadmap or algorithm is needed to help new designers identify the best path forward.

ASHRAE 90.1’s performance-based methods within the prescriptive path

The prescriptive compliance path is typically the most familiar, allowing each discipline to operate relatively independently of one another. Building designs following the prescriptive path must comply with Sections 5 to 11, which cover the building envelope, HVAC, service water heating, power, lighting, other equipment and additional efficiency requirements. However, even within the prescriptive path, performance-based options exist for certain disciplines.

For building envelope, Section 5.5 offers a fully prescriptive path, while Section 5.6 enables a performance-based approach. This approach allows for trade-offs between different envelope materials or subassemblies if the overall envelope performance meets the specified criteria. The procedure for the envelope trade-off approach is outlined in Appendix C. Energy modeling is required for this path, which often falls outside the architect's scope of expertise, meaning that the engineering team needs to be included even if energy modeling is not otherwise required.

HVAC systems have three compliance paths within the prescriptive path: the simplified approach (Section 6.3), the prescriptive path (Section 6.5) and the mechanical system performance rating method (Section 6.6), which was added in the 2022 edition. The MSPR allows for trade-offs within HVAC systems but not with other disciplines like the envelope trade-off approach mentioned above.

As seen in Equation 1, the new approach compares energy efficiency, known as the total system

performance ratio (TSPR), of the proposed design with that of a baseline HVAC system, normalized by a given mechanical performance factor. A new appendix, Appendix L, covers the calculation procedures.

One benefit to the MSPR is that, while it does require energy modeling, it allows for simplifications, such as reducing the building geometry to simple shapes. This may be very useful on small renovation projects, although the utility of this simplified approach is likely reduced on new buildings or complete renovations/alterations, where the building geometry must be modeled to a reasonable degree of accuracy for building loads.

3: To successfully identify the best path forward, it’s important to establish early collaboration among the entire project team, including engineers, architects and contractors.

Courtesy: Dewberry

FIGURE

FIGURE 2: Obtaining hands-on experience is critical to understanding the nuances of evolving codes and standards. Courtesy: Dewberry

BUILDING SOLUTIONS

Equation 1:

TSPR p > TSPR r / MPF

Where:

TSPR p = proposed TSPR

TSPR r = reference TSPR MPF = mechanical performance factor

New for ASHRAE 90.1-2022 are the additional efficiency requirements in Section 11, which cover all disciplines in Sections 5 to 10. Having experience with U.S. Green Building Council LEED or

other points-based building energy performance rating systems is helpful for understanding this section. There are 33 individual energy efficiency measures to choose from and while most of the measures do not require the creation of an energy model, some of the most substantial, such as E01: Improved Envelope Performance, do require energy modeling. Future measures are likely to continue moving in this direction.

Performance-based compliance within ASHRAE 90.1

The energy cost budget (ECB) method has been around in some form or another since ASHRAE Standard 90-1975 was first published and computer-based, 8,760-hour energy simulations were first mentioned in ASHRAE 90.1-1989.

However, it’s not uncommon for the prescriptive method to be preferred, as it was often simpler to understand, required less interdisciplinary coordination and computing power and was usually easily achievable. The ECB was only used as a last resort if some unique building property made the prescriptive path not feasible.

In the years since, the prescriptive requirements have become increasingly stringent, while at the same time architectural designs have grown more complex. Fortunately, computing power is no longer the concern it once was, making the ECB more attractive. The ECB essentially compares the estimated annual cost of energy for the proposed building against that for a minimally compliant building, using the requirements given in the prescriptive path.

Equation 2:

DEC < ECB x (1 – ECreq / 1,000 x Aadj)

Where:

DEC = design energy cost

ECB = energy cost budget

EC req = energy credits required per Section 11 Aadj = an adjustment factor to normalize additions or alterations by the total area in the model

In terms of compliance, the performance rating method (PRM) is a relative newcomer to ASHRAE

FIGURE 4: This visual representation can help designers determine the best path to compliance. Courtesy: Dewberry

FIGURE 5: The Countryside Municipal Complex project focused on a variety of design solutions to create a building that maximizes the client’s desire to have an energy-efficient and sustainable facility.

Courtesy: Dewberry

90.1. First appearing as an informative appendix in 2004, it was not officially considered part of the standard.

However, it has subsequently been promoted first to a normative appendix (2010) and finally to a third compliance path (2016). Like the ECB, it compares the proposed building against a baseline and allows for tradeoffs between disciplines, while allowing for even more flexibility than the ECB.

The energy model for the proposed design is compared to a more normative baseline building than that used in the ECB. This baseline model uses standardized HVAC systems and the same percentage of glazing on each wall, among other characteristics as required by Appendix G. Furthermore, the baseline building energy performance is simulated after it is rotated 90, 180 and 270 degrees in addition to the actual orientation, with the results of all four orientations being averaged.

How addenda to ASHRAE Standard 90.1-2022 affect design

THE STANDARD IS UPDATED every three years, and addenda directly affect design.

Almost as soon as ASHRAE standards are published, subject matter experts, industry professionals and other interested parties begin to propose addenda. In the case of flagship standards, such as ASHRAE Standard 90.1: Energy Standard for Buildings Except Low-Rise Residential Buildings, there can be dozens of addenda, which are usually incorporated into the next edition. As of this writing there are 33 published addenda to Standard 90.1, which can be found on ASHRAE’s website. Of these, Addenda a, f, j, l, n and au all either clarify or improve upon one of the performance-based compliance paths, further encouraging their use.

Addendum f allows engineers to take credit for energy efficiency measures that are required by Section 11 in the prescriptive path when using the energy cost budget or performance rating method, making these two performance-based paths even more attractive.

‘New and experienced engineers alike should keep abreast of the latest addenda to stay ahead of the game.’

Addendum l adds an entirely new informative appendix, Appendix M, which provides jurisdictions with a path to net zero operational energy emissions over the course of multiple code cycles. While compliance with informative appendices is not required, it is worth noting that the performance rating method also started out as an informative appendix. Even if Appendix M is not eventually elevated to a normative appendix, the fact that it is written as code enforceable language ready for use by authorities having jurisdiction means that for more climate focused local governments, compliance with ASHRAE Standard 90.1 could mean compliance with this appendix.

With ASHRAE’s recent establishment of the Center of Excellence for Building Decarbonization and the stated goal of ASHRAE Standard 90.1 becoming a net zero carbon code by the 2031 edition, new and experienced engineers alike should keep abreast of the latest addenda to stay ahead of the game.

The result of the simulations is the calculation of a performance cost index, as shown in Equation 3. Because the proposed building is rated against a baseline building of the same footprint, the methods for calculating the baseline performance do not need to change much from one edition of the standard to another; the target performance cost index (PCIt) can simply be decreased.

BUILDING SOLUTIONS

CODES AND STANDARDS

FIGURE 6: Having experience with U.S. Green Building Council LEED or other points-based building energy performance rating systems is helpful for understanding ASHRAE 90.1

Section 11. Courtesy: Dewberry

Equation 3:

PCI = PBP / BBP

Where:

PCI = Performance cost ndex

PBP = Proposed building performance

BBP = Baseline building performance

Who determines the compliance path?

As energy standards continue to become more stringent and complex and push for performance-based compliance, mechanical and electrical designers will often be asked to advise and assist in achieving a code-compliant project. Even if the prescriptive path is the compliance method chosen, securing the additional energy credits required by Section 11 will require increased collaboration between the various design team disciplines.

While an integrated design approach is strongly recommended, at the very least a meeting solely focused on energy code compliance should be held at the beginning of the project. While the mechanical and electrical disciplines may not own the project, it is their responsibility to push, if need be, for inclusion as early as possible in the design process.

They will also be called on to educate the design team on new energy code requirements, including the expanded commissioning requirements, which are often forgotten. Scheduling an energy code coordination meeting early in the design process will be beneficial to all stakeholders. During this meeting, each discipline should identify the subpath of the overall prescriptive path they intend to pursue and whether they have identified any challenges with meeting code compliance.

Achieving ASHRAE 90.1 compliance

The robust nature of ASHRAE Standard 90.1 can make it difficult to determine which path to pursue. Choosing a compliance option will allow designers a reference point as energy questions arise. While there is no one-size-fits-all approach for selecting the best path, following a flow chart can help identify the best course of action (see Figure 2). The idea is to ask a series of questions at the beginning of a project that will lead to achieving energy compliance with fewer difficulties. The algorithm is presented as a flow chart and consists of the following series of yes or no questions:

• Is there a desire for beyond-code building performance? In this context, beyond code refers to anything above and beyond the base requirements

of ASHRAE 90.1, such as a formal certification program like LEED, Green Globes or Energy Star, a state or federally required stretch code or a client’s desire for sustainable building performance, often phrased as “LEED-lite” or “as close to net-zero as possible.” If the answer to this question is yes, then the PRM should be used. This method has long been required for many of the formal programs mentioned above and has been an acceptable method of proving code compliance since the 2016 edition of the standard.

• Is the project a new building or an addition? New buildings and additions depend heavily on the characteristics of the building envelope for energy performance. At the energy code compliance coordination meeting, the design team should review the prescriptive requirements of the building envelope section and identify potential challenges. If it is a simple building and the architects do not anticipate any significant challenges with the prescriptive path, the team should continue with questions the next questions. Challenges with prescriptive compliance often come in the form of fenestration exceeding the allowable limits found in Section 5.5.

– If such challenges are identified, there are generally two options: the envelope trade-off or a performance-based path. Since the envelope trade-off option under Section 5.6 already requires energy modeling and because Section 12 is more flexible by allowing for tradeoffs between all disciplines, it likely makes sense to pursue the energy cost budget method.

• Does the design team perceive any challenges in complying with Section 11 of the standard? These issues could range from technical challenges to obtaining certain credits to simply not wanting to spend time evaluating each point and completing subsequent documentation. As compliance with Section 11 is not required for the performance-based paths, the energy cost budget method is likely to save overall time and effort.

• Will energy credits that require energy modeling, such as improved envelope performance (E01), be pursued? If so, the creation of an energy model lends itself to performance-based compliance.

• Is energy modeling required for the mechanical, electrical and plumbing design? Certain design choices, such as geothermal systems or energy storage, are likely to require an energy model as a mat-

ter of best practice. Again, the energy model lends itself to a performance-based path.

• Does the mechanical team anticipate any challenges meeting the prescriptive requirements of Section 6.5? Certain design constraints can sometimes cause challenges in meeting the minimum efficiency requirements in Section 6.5. If there are no issues with Section 6.5, then the prescriptive path can be used. If challenges are identified, then one final question should be asked.

• Is simplified building geometry acceptable for a loads/energy model? If the project is a relatively simple building or a renovation, an energy model with simplified building geometry may be acceptable. In this case, the mechanical team may decide to use the mechanical system performance rating method, which is otherwise a part of the overall prescriptive path but allows for tradeoffs between mechanical equipment. If simplified building geometry is not acceptable, which is likely to be the case with a new building for which a loads model has been created, then the energy cost budget should be used. If the mechanical team does not foresee any challenges to prescriptive compliance, then the overall prescriptive path can be used.

The ongoing evolution of ASHRAE 90.1

As energy codes continue to evolve, understanding and effectively navigating the compliance paths of Standard 90.1 is crucial for designing code-compliant buildings and delivering successful projects. A collaborative approach among architects, engineers and contractors is essential for successful building performance. Open communication, early coordination and a shared understanding of energy performance goals are vital.

While a framework is helpful for decision-making, ASHRAE 90.1 will continue to change and it is important to stay updated on the latest requirements. By following a structured decision-making approach to choosing an ASHRAE Standard 90.1 compliance path, engineers can navigate the complexities of energy efficiency requirements and lead their project teams to achieve energy-efficient building designs. cse

Patrick Ryan, PE, CEM, is a mechanical engineer and Deputy Discipline Lead at Dewberry.

‘A collaborative approach among architects, engineers and contractors is essential for successful building performance. ’

csemag.com

ASHRAE 90.1 insights

uThe increasing demand for energy efficiency is driving a shift toward performance-based code compliance and ASHRAE 90.1 rises to the forefront.

uBecause of the everincreasing complexity, many senior engineers are not far ahead of their junior counterparts and in the absence of their guidance, a structured decision-making approach is essential.

Bill Kosik, PE, CEM, LEED AP, kW Mission Critical Engineering, Member of WSP, Chicago

Why and how to adopt the IECC for energy-efficient designs

By understanding the International Energy Conservation Code (IECC), engineers can interpret codes and standards appropriately for design purposes.

Since 2000, when the International Energy Conservation Code (IECC) was first published by the International Code Council (ICC), it has been updated every three years to incorporate new technologies and provide energy efficiency guidance and conformance requirements for new building types.

From the beginning, IECC incorporated ASHRAE Standard 90.1: Energy Standard for Buildings Except Low-Rise Residential Buildings to define minimum energy efficiency standards requirements for building components (lighting, glazing , roofing, insulation, etc.), service water heating and and power and cooling systems. As ASHRAE Standard 90.1 has evolved, the IECC has

1: If a governmental agency or authority having jurisdiction (AHJ) wants to adopt a model code, it will enact an ordinance, regulation or law and incorporate the model code by reference. Courtesy: Bill Kosik, WSP

also progressed to encompass new building methods and advancements.

Directly referencing ASHRAE Standard 90.4: Energy Standard for Data Centers exemplifies how IECC has progressed in demonstrating energy efficiency compliance for data centers.

The IECC is a model building code that provides minimum design and construction requirements for energy efficiency. It aims to reduce energy consumption in residential and commercial buildings by setting minimum energy performance standards:

1. Building envelope: An efficient building envelope, comprised of exterior walls, roofs, windows, doors is designed to minimize heat loss/gain, solar load and and air infiltration.

2. Heating, ventilation and air conditioning (HVAC): HVAC systems are the greatest energy consumers in a commercial building. A significant portion of the IECC is dedicated to meeting minimum energy efficiency standards.

3. Lighting: The IECC's lighting efficiency requirements, along with natural lighting and controls, requirements ensure the optimal mix of lighting quality and energy use. Natural lighting and control systems will also reduce energy use.

4. Lighting compliance paths: Depending on the building type and construction, the IECC includes various methods for demonstrating compliance with the stated requirements. These include prescriptive and paths, performance-based paths and and the use of approved software tools.

The IECC has a three-year review cycle and is updated to incorporate the latest design and con-

FIGURE

‘State governments and local municipalities can adopt the IECC in whole or in part.’

struction technologies, including the latest building energy efficiency research. State governments and local municipalities can adopt the IECC in whole or in part. Local municipalities often adopt the IECC with modifications that reflect specific climate and energy efficiency goals.

How the content of the IECC is determined

The process of developing/revising the language in IECC is done in an international forum consisting of design and construction professionals, equipment manufacturers, building science experts and and others from the code enforcement community. The forum aims to review proposed changes that improve safety, performance and and technological advances in construction techniques and products.

The discussions are transparent and follow openness, due process and and balance principles. The ICC has a detailed process for voting on code changes, starting with proposal submissions, committee hearings, public comments and hearings, government consensus votes and validation/publication. The number of the ICC voting representatives is based on population and is defined in the ICC bylaws.

Applying the IECC to state and municipal governments

Building codes are part of a state’s compiled statutes (law or agency enforcement) and include state-specific requirements that must be followed under the law or per a state agency. Instead of developing and maintaining a custom code, a state will adopt a model building code, reducing the cost and complexity of enforcing requirements. Using a model code also reduces efforts when updating new technologies and safety protocols. But this is not a one-size-fits-all solution — there are different

FIGURE 2: This shows the ASHRAE Standard 90.1 savings, year over year.

Courtesy: Pacific Northwest National Laboratories, DataHub

methods of how the states and municipalities adopt codes:

• State-level adoption: In some states, building codes are adopted at the state level. Local municipalities must strictly follow the language and intent of the state codes.

• State codes with local amendments: States adopt building codes at the state level but with built-in flexibility for allow municipalities to make amendments to address local conditions.

• Local adoption: Building code adoption is left entirely to local jurisdictions. This method can result in differences or contradictions between the local jurisdiction and state regulations (see Figure 1).

How is ASHRAE 90.1 applied within the IECC framework?

ASHRAE 90.1 is the de facto standard for energy efficiency in buildings. It is a “code-ready” standard, meaning local jurisdictions can tailor it and use it as their energy code. The standard has been around since 1975 and has been adopted in the U.S. and around the globe.

In 2009, ASHRAE 90.1 was mandated to be used by federal agencies as the minimum energy efficiency requirement for new federal buildings (see Figure 2).

Objectives Learningu

• Learn that building codes typically fall under the statutes of the state, enacted by the legislature or assigned to a state agency.

• Understand how data center-specific standards and guidelines have advanced over time.

• Identify how the IECC has been updated to include data center energy conformance requirements, specifically how the ASHRAE Standard 90.4 has been incorporated in the IECC editions.

BUILDING SOLUTIONS

FIGURE 3: In addition to changing the compliance process in ASHRAE 90.4 from 2016 to 2022, the mechanical load component (MLC) values are more stringent across all climate zones. ASHRAE acknowledged that the MLC values in the 2016 edition needed to be lowered to ensure reasonable energy efficiency.

Courtesy: Bill Kosik, WSP

According to the Building Codes Assistance Project, 38 states have adopted ASHRAE 90.1. International energy standards — very close in content and scope to Standard 90.1 — are also used in India, Canada, Mexico, Dubai, Singapore, Ireland, Hong Kong and other locations.

Finally, in addition to being a template for municipal and state codes, Standard 90.1 is integral to the ANSI/ASHRAE/ICC/USGBC/IES

International Green Construction Code Standard (IgCC). While there are differences between Standards 189.1 and 90.1, many provisions in the IgCC are taken directly from or based on ASHRAE 90.1. Also, Green Building Initiative’s Green Globes and the U.S. Green Building Council LEED use ASHRAE 90.1 as the basis for demonstrating minimum energy efficiency compliance.

ASHRAE 90.4 as an alternate compliance path

Diving deeper into ASHRAE 90.1, Chapter 6 contains a section on “alternate compliance paths” for HVAC systems. An alternate compliance path is used to demonstrate regulatory or certification requirements using a nonstandard approach. Using this method provides an opportunity to work with the local permitting officials and reach a consensus on the viability of the approach.

However, using an alternate compliance path still requires meeting prescriptive requirements for building components such as building envelope and lighting.

An example of this is found in Section 6.6.1 of Standard 90.1. This section provides guidance for an optional path called “Computer Room Systems Path” and allows for the use of ASHRAE 90.4 for computer

‘An alternate compliance path is used to demonstrate regulatory or certification requirements using a nonstandard approach.’

rooms that have an information technology equipment (ITE) load greater than 10 kilowatts (kW). This provides an advantage to the engineer because ASHRAE 90.4 is written solely for data centers and contains specific methods and language.

Using the ASHRAE 90.1 as an alternate compliance path in the IECC

The 2024 edition of IECC includes an introductory note indicating that Chapter 4 provides options for complying with the energy efficiency provisions, including a performance alternative for designs that do not use the prescriptive method. Section C401.2 indicates that commercial buildings shall comply with:

• C401.2.1 — IECC (prescriptive path or using building energy use simulation), or

• C401.2.2 — follow the requirements on ASHRAE 90.1 (as the alternative compliance path). cse

Bill Kosik, PE, CEM, LEED AP, is an Assistant Vice President, Senior Technical Manager, Mechanical Engineering at WSP. He is a member of the Consulting-Specifying Engineer editorial advisory board.

csemag.com

IECC insights

u The International Energy Conservation Code (IECC) is a model building code that provides minimum design and construction requirements for energy efficiency.

u This article identifies and examines the connections between IECC, ASHRAE 90.1 and ASHRAE 90.4

BUILDING SOLUTIONS

Richard Vedvik PE, CHEPP, Principal, IMEG, Rock Island, Illinois

Documentation revisions in the 2025 NFPA 72 code

Updates

to NFPA 72 introduce changes to definitions and documentation, enhancing clarity and reliability.

The 2025 edition of NFPA 72: National Fire Alarm and Signaling Code introduces several distributed changes to documentation and definitions, focusing on enhancing clarity, accountability and system reliability. These updates include refined definitions for personnel roles, expanded requirements for shop drawings and completion records, and updates to testing and integration protocols. There are also entirely new sections to keep up with emerging technologies and network-connected systems. Collectively, these changes aim to ensure that fire alarm and emergency communication systems are modern, comprehensively documented and safely connected.

Clarifications for authorized and emergency personnel

• Identify definitional changes in the 2025 version of NFPA 72.

• Understand cybersecurity concerns and updates.

• Learn changes to personnel roles, shop drawings and integration protocols.

The updated commentary for “authorized personnel” and “emergency personnel” in Sections 3.3.213.1 and 3.3.213.2 clarify roles and responsibilities, specifically for operational accountability. Authorized personnel are identified as individuals selected by property owners to manage and maintain fire alarm and safety equipment. These individuals, whether employees or external contractors, are required to possess specialized knowledge of the systems they oversee, ensuring that maintenance and troubleshooting are performed competently.

The definition of emergency personnel, originally introduced in the 2022 edition, has been further refined to distinguish the varying levels of training among individuals responding to emergencies. For example, a fire alarm vendor tasked with testing a

fire alarm system has different expertise compared to a firefighter focused on extinguishing fires and rescuing occupants.

Shop drawing enhancements

Sections 7.4.7.1 and 7.4.7.2 list requirements for shop drawings. This section addresses a critical aspect of system design and documentation. Shop drawings shall include detailed information about control unit diagrams, equipment identification, locations, wiring, manual controls and connections to supervising stations or emergency safety systems. By standardizing the level of detail required in shop drawings, the code ensures that all stakeholders, from designers to installers, have a clear understanding of system configurations. These documents are vital for future troubleshooting, and including all locations of splices and junctions can speed repairs.

Testing updates for emergency responder systems

Section 14.4.10 provides updated testing requirements, reflecting the growing integration of emergency responder communication enhancement systems (ERCES) with fire alarm systems. Section 14.4.10.1 now mandates the monitoring of supervisory signals from ERCES through the fire alarm system. This addition underscores the importance of seamless integration between these systems, ensuring real-time oversight and enhancing emergency response capabilities. Designers must now ensure that ERCES monitoring is included in system configurations, aligning with the expanded scope of testing requirements.

Integration with life safety networks

The 2025 edition also addresses the growing complexity of integrating fire alarm systems into broader life safety networks. Revisions to section 21.2.4.1 differentiate between physical protec-

tion requirements for emergency control function conductors installed without raceway for three feet or in raceway for 20 feet. Section 21.2.11 was reorganized to more clearly identify monitoring requirements for data communication paths. If a communication failure occurs, the system must trigger a trouble signal within 200 seconds, ensuring prompt detection and resolution.

In addition, the code clarifies that data from non fire alarm systems can only display status information and must not interfere with the functionality of the fire alarm system. This safeguard maintains the operational integrity of fire alarm systems while enabling interoperability with other life safety components. Designers must carefully evaluate system interfaces to ensure compliance with these stringent requirements, particularly in facilities with complex, interconnected safety systems.

Elevator emergency recall requirements

Updates to Section 21.3 reorganize requirements for elevator emergency recall operations, particularly in facilities without a required building fire alarm system. Section 21.3.2 specifies that initiating devices for Elevator Phase I Emergency Recall Operation must connect to either a non-required fire alarm system or a dedicated “elevator recall and supervisory control unit.” These units must be permanently labeled and documented in record drawings, providing clear identification of their purpose and ensuring compliance during inspections or system modifications.

Expanded carbon monoxide detection standards

The definition of "carbon monoxide source" (3.3.39) has been updated to reflect that CO production is not limited to fuel-burning appliances. This broader definition requires designers to consider CO detectors in locations beyond those traditionally associated with fuel-based systems. To support this change, a new definition for "unconditioned areas" (3.3.329) has been added. This definition addresses spaces such as attics, crawlspaces and garages, where environmental conditions may pose challenges to CO detector placement and operation.

Chapter 17 now reflects these updated definitions, with Section 17.14.1 removing references to fuel-burning sources and focusing on CO sources generally. This revised language introduces references to laws, codes and standards, ensuring that

installations align with broader regulatory frameworks. Section 14.4.4.6 is the new home for mandatory testing requirements for CO detection devices.

New detection technologies

The 2025 edition incorporates significant advancements in detection technologies, including acoustic and thermal image detectors. Section 17.11 introduces acoustic leak detection systems, defined in 3.3.79.1 as devices that identify ultrasonic sounds from high-pressure gas leaks. Unlike conventional gas detectors, which sense the presence of gas directly, acoustic systems detect sound patterns associated with leaks, making them particularly effective in industrial environments or locations with rapid gas dispersion. To ensure proper implementation, design documentation must outline performance objectives and provide engineering evaluations for detector placement and spacing. These systems must also align with manufacturer recommendations to mitigate interference and meet the performance requirements outlined in relevant code chapters.

Thermal imaging fire detectors, defined in 3.3.79.26 and addressed in Section 17.12, represent another technological addition. 14.4.3.4 added these devices to the list of testing requirements. These devices detect temperature changes and fire signatures using thermal imaging technology. They require clear lines of sight to potential hazards and must produce alarms for temperature

FIGURE1: Fire alarm systems are increasingly interconnected and new updates to NFPA 72 work to address this. Courtesy: IMEG Corp.

‘

The 2025 edition incorporates significant advancements in detection technologies, including acoustic and thermal image detectors.

’

BUILDING SOLUTIONS

rate-of-rise within their field of view. Supervisory signals are also required to notify system operators of obstructions that may impair detection. Controls and software must be secured against unauthorized modifications, ensuring system integrity.

Clarifications for smoke detection systems

72 insights u New sections in the 2025 version of NFPA 72 address emerging technologies and network-connected systems.

u Cybersecurity concerns in fire alarm systems are addressed throughout multiple sections of the updated code.

The spacing requirements for smoke detectors have been updated in Section 17.7.4.2.3.1 to extend the prescriptive coverage area maximum to 40 feet high ceilings. For higher mounting heights, performance-based calculations shall be used. Staying with the theme of ceiling mounted detection, section 17.7.4.2.4.2 now includes the definition of "girder" to clarify ceiling type descriptions, ensuring consistent application of spacing guidelines across various architectural configurations. Additionally, Section 17.7.6.6.5.1 revises the requirements for placing smoke detectors near doorways. Previously, devices were required to be located on the exact centerline of the door opening, which proved overly rigid in many applications. The updated code now allows placement within 12 inches of the centerline, balancing practical installation concerns with functional performance.

Suppression system signage requirements

Section 17.17.3 introduces a new requirement mandating signage for manual operation of releasing agent suppression systems. This change

addresses a long-standing issue where many existing installations lacked adequate signage, potentially hindering system operation or causing accidental discharge.

Emergency control function interfaces

The 2025 edition revises the guidelines for emergency control function interface devices, as detailed in Section 21.2.4. These devices link detection systems with controlled components, such as ventilation or suppression systems. The revised code permits devices to be installed up to 20 feet from the controlled component if conductors are protected in metal raceways or armored cables. Without such protection, the installation must still remain within three feet of the component.

Notification appliance circuits and voice instruction overrides

Section 18.3.7.1 has been revised to separately address alternating current and direct current circuits powering notification appliances. It’s vital to ensure voltage drop is adequately controlled for proper operation of notification appliances. The two calculation methodologies listed are end-lineloaded and point-to-point (PTP). The former is the most conservative, because it assumes all of the devices are at the end of the total wire length. All else equal, we expect the PTP method to look more favorable and result in smaller wire sizes. Designers should specify the type of calculation method to be used and carefully review the calculation method used in the shop drawing submittal.

Section 24.5.12.6 was rearranged to emphasize the importance of life safety voice instructions overriding any previously initiated or automatically initiated signals. This ensures that critical information delivered during emergencies is not hindered or obscured by other ongoing alerts. For engineers, this necessitates system designs where voice instruction capabilities are seamlessly integrated and prioritized, particularly in facilities with complex emergency scenarios or diverse occupant needs.

Mass notification and emergency communication systems

Section 24.7.1 addresses the use of distributed recipient mass notification systems (DRMNS). DRMNS cannot replace required audible and visual

FIGURE 2: NFPA 72 addresses increased cybersecurity concerns along with functionality and reliability issues.

Courtesy: IMEG Corp.

notification systems, though it encourages integration with mass notification systems (MNS) whenever possible. This reinforces the role of traditional notification systems as the foundation for emergency communication, with DRMNS serving as a supplementary tool for delivering targeted and specific messages. The revisions ensure that redundancy and flexibility are built into notification system designs to enhance overall reliability.

Section 24.9.1 introduces a requirement for fire alarm systems to monitor all supervisory signals related to emergency responder communication enhancement systems (ERCES). This update increases the number of required monitoring points, necessitating systems capable of handling additional complexity. By strengthening oversight of ERCES, the revisions improve the integration of communication systems with fire alarms, which ensures seamless operation during critical events.

Supervising stations and pathway survivability

Requirements for proprietary supervising stations, detailed in Section 26.4.3.4.3, mandate the inclusion of emergency lighting capable of providing at least 26 hours of illumination during primary lighting failures. This requirement, along with adherence to Chapter 14 testing standards, ensures that supervising stations remain operational even during extended power outages.

The integrity of communication pathways between fire alarm systems and supervising stations is addressed in Sections 26.6.3.3, 26.6.3.11, 26.6.3.12 and 26.6.3.13. These revisions account for the behavior of internet service providers during outages, introduce requirements for trouble indications on fire alarm control units in the event of communication loss and mandate secondary power for communication equipment. Additionally, Section 26.6.5.1.2 provides stricter supervision and control requirements for radio transmission equipment, to ensure the continuous operation of remote communication systems. Together, these changes reflect a concerted effort to address real-world connectivity challenges, reinforcing the reliability of communication systems under various conditions.

Section 27.8.7 also updates pathway survivability for public emergency alarm reporting systems. The code now requires connections between

these systems to achieve level two or level three survivability, significantly improving their reliability during extreme conditions.

Audible alarm characteristics and restricted audible mode operation

The characteristics of audible alarms are refined in Sections 10.10.4 through 10.10.8, which were revised for clarity. These sections require distinct and recognizable sounds for supervisory, trouble, evacuation alarm and pre-alarm signals. These updates enhance clarity and reduce confusion, particularly in facilities where multiple alarm types may need to operate simultaneously.

The introduction of restricted audible mode operation (RAMO) in Section 18.4.8 addresses the need for tailored auditory environments in sensitive spaces, such as neurodiverse facilities or early education classrooms. RAMO allows for reduced sound levels in private-mode notifications but is restricted to areas with trained, awake and mobile staff. The code includes detailed documentation requirements for RAMO zones, outlined in Section 7.3.4.7, and mandates annual testing and occupancy reviews to verify compliance with the intended use.

The 2025 edition also updates Sections 18.4.1.5, 18.4.1.6 and 18.4.1.7 to align with RAMO requirements, further integrating these systems into the broader framework of fire alarm notification standards.

Incorporating cybersecurity provisions

The 2025 edition of NFPA 72 expands the chapter on cybersecurity, establishing enforceable standards to safeguard fire alarm and signaling systems from unauthorized access and cyber threats. Building on the guidance provided in Annex J of the 2022 edition, this chapter consolidates and expands the cybersecurity framework, addressing vulnerabilities in system access, configuration and implementation.

The 2025 edition draws upon well-established frameworks to provide a solid foundation for cybersecurity practices. New references to the International Society of Automation (ISA) and the

3: Regular checks on the functionality of alarm systems is key to ensure safety during an emergency event. Courtesy: IMEG Corp.

‘

NFPA 72 expands the chapter on cybersecurity, establishing enforceable standards to safeguard fire alarm and signaling systems from unauthorized access and cyber threats.

’

FIGURE

BUILDING SOLUTIONS

National Institute of Standards and Technology (NIST) emphasize best practices for securing industrial automation and control systems. These standards, referenced in Sections 2.3.6 and 2.3.8, encourage the integration of systematic and comprehen-

sive security protocols to mitigate risks associated with network connectivity. Several new and revised definitions in the 2025 edition of NFPA 72 provide essential clarity for implementing cybersecurity measures. The term auxiliary ser-

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vice provider (ASP) refers to an entity that processes signals from fire alarm systems and relays them to supervising stations, ensuring that signals do not bypass critical security checkpoints. The definition of network connectable equipment encompasses components capable of connecting to external networks via wired or wireless protocols, highlighting the importance of securing these interfaces. The code also introduces cybersecurity software, which protects systems against cyberattacks without disrupting their primary functionality. Updates to the definitions of emergency response agency and emergency response facility align with the 2022 edition of NFPA 1225: Standard for Emergency Services Communications, ensuring consistency across standards. These clarified terms provide a structured vocabulary for designing and implementing secure systems.

Auxiliary service providers

Section 26.2.11 details the role of ASPs and establishes requirements to enhance signal reliability and supervision. ASPs are often cloud-based entities responsible for monitoring and retransmitting signals from protected premises to supervising stations. To address potential vulnerabilities, ASPs must ensure continuous supervision of communication pathways, retransmit signals without delay and notify stakeholders of any operational changes within 30 days. They are also required to retain signal records for at least one year and comply with UL 827 standards for security and reliability.

Implementing maintenance plans for networked systems

Section 7.6.7 introduces a new requirement for maintenance plans tailored to network connectable equipment. These plans must document personnel with access to the system and outline procedures for removing access credentials promptly when personnel changes occur. This focus on access management reduces the like-

Fluting Damage

lihood of unauthorized system interactions and ensures that only qualified individuals can control critical system components.

Gateway reporting system qualifications

Section 10.5.7 introduces qualifications for personnel managing gateway reporting systems, emphasizing the need for expertise and accountability. Individuals responsible for designing, installing, maintaining or servicing these systems must be trained, certified and qualified according to standards established by state, national or manufacturer guidelines. Furthermore, documentation of these qualifications must be kept up to date and made available to the authority having jurisdiction upon request.

Mandatory cybersecurity provisions in Chapter 11

Chapter 11, which is mostly new in the 2025 edition, consolidates cybersecurity practices into a comprehensive framework of mandatory requirements. It replaces the optional guidance previously outlined in Annex J, addressing vulnerabilities in system access and configuration identified in foundational research. The chapter includes protocols for securing system access points, protecting system configurations from tampering and implementing best practices during system deployment. By shifting from optional recommendations to enforceable standards, Chapter 11 underscores the importance of prioritizing cybersecurity as a fundamental aspect of system design and operation.

The introduction of these cybersecurity provisions highlights the increasing complexity of fire alarm and emergency communication systems in the context of networked environments. For engineers and designers, these updates necessitate a proactive approach to system security, including the incorporation of redundant communication pathways, robust access controls and comprehensive personnel training programs. Additionally, integrating cybersecurity software during the design phase helps protect system integrity while ensuring compliance with the new standards. cse

Richard Vedvik PE, CHEPP, is a senior electrical engineer and acoustic engineer with IMEG. He is a member of the Consulting-Specifying Engineer editorial advisory board.

FIGURE 4: Auditorium spaces like this one at the University of Florida have specific considerations for fire and life safety.

Courtesy: IMEG Corp.

BUILDING SOLUTIONS

Tom Divine, PE, Johnston, LLC; Houston

Do you know the requirements for emergency lighting systems?

Emergency lighting requirements derive from provisions of various building codes. Requirements are complex and can be difficult for an electrical engineer to locate in the heat of battle.

“Emergency lighting” refers to the systems and equipment that illuminate a building when normal power fails. Its primary purpose is to facilitate quick, safe egress, so it’s overwhelmingly directed at lighting and marking the paths to building exits, particularly to escape a fire or other advancing peril. Other purposes include support of rescue efforts, support of power restoration efforts and amelioration of the tendency of building occupants to panic when suddenly and unexpectedly immersed in darkness.

Objectives Learningu

• Become familiar with the primary codes governing the location and characteristics of emergency lighting systems and equipment.

• Know the technical requirements for emergency lighting performance in the absence of utility power.

• Understand requirements for installation, testing and ongoing maintenance for emergency lighting installations.

FIGURE 1: A battery-powered light unit in the corridor of a business occupancy. The test switch and indication lamp can be seen adjacent to the luminaire. Courtesy: Johnston, LLC

In view of the importance of emergency lighting to the safety of building occupants, the various building codes and the plan reviewers, building inspectors and fire marshals that enforce them take a serious view of emergency lighting requirements. A thorough understanding of code requirements for emergency lighting is essential to get a set of documents through permit and to get a facility to a certificate of occupancy.

The sometimes-arcane language of the codes might lead to differences of opinion about what their various provisions of the codes mean. Where any doubt exists, it’s important to clarify requirements with authorities having jurisdiction (AHJ) ahead of permit and construction to avoid embarrassment and unpleasant surprises at completion.

Emergency lighting codes and standards

The codes listed below provide requirements for emergency lighting systems. These editions are referenced in this article:

• International Building Code (IBC), 2021 edition: The IBC sets minimum requirements for building systems. It’s enforced by most jurisdictions in the United States. Requirements for emergency lighting are found in Sections 1008, Means of Egress Illumination and in 1013, Exit Signs.

•NFPA 70: National Electrical Code (NEC), 2023 edition: The NEC is the installation code covering requirements for electrical equipment and installations. The NEC is enforced by an overwhelming majority of jurisdictions in the United States and in many other parts of the world. All emergency lighting is powered from building electrical systems; consequently, many sections of the NEC describe requirements related to emergen-

FIGURE 2: A supplementary, motion-sensitive, battery-powered luminaire in the stairwell of an apartment house. This unit is not listed for emergency use. Powered by primary batteries, its purpose is to provide illumination for the residents' convenience after emergency batteries in bona fide emergency fixtures have discharged. Courtesy: Johnston, LLC

cy lighting systems. The portions of the NEC most directly affecting emergency lighting are found in Article 700, Emergency Systems.

• NFPA 99: Health Care Facilities Code, 2021 edition: NFPA 99 describes requirements for systems installed in health care facilities. Standby lighting that functions much like emergency lighting is required for a few specific locations in NFPA 99.

• NFPA 101: Life Safety Code, 2021 edition: NFPA 101 defines minimum building requirements to provide a measure of protection to building's occupants from fire, smoke, toxic fumes and other hazards. NFPA 101 is intensely concerned with building egress and, therefore, with illumination of egress paths under emergency conditions. Emergency lighting requirements requirements are detailed in Sections 7.8, Illumination of Means of Egress; 7.9, Emergency Lighting; and 7.10, Marking of Means of Egress.

• NFPA 110: Standard for Emergency and Standby Power Systems, 2022 edition: NFPA 110 prescribes requirements for emergency power systems — primarily, but not exclusively generators — that support loads whose failure could result in severe injury to humans. A few portions of NFPA 110 are specifically applicable to emergency lighting: Chapter 4, Classification of Emergency Power

FIGURE 3: Artist's conception of an exit sign using a pictogram. The pictogram is called "Running Man," and is commonly used in Europe, where the diversity of language is much greater than in the United States. Under NFPA 101, similar pictograms may appear on exit signs in the United States with authority having jurisdiction approval. Courtesy: Johnston, LLC

Supply Systems; 7.3, Lighting at the generator location; and 8.3, Maintenance and Operational Testing.

• NFPA 111: Standard on Stored Electrical Energy Emergency and Standby Power Systems, 2022 edition: NFPA 111 primarily covers battery-supported systems, though it also covers fuel-cell cell systems. It does not cover battery-supported luminaires. Applicable chapters include Chapter 4, Classification of Stored-Energy Emergency Power Supply Systems and Chapter 8, Routine Maintenance and Operational Testing.

‘A thorough understanding of code requirements for emergency lighting is essential to get a set of documents through permit and to get a facility to a certificate of occupancy.’

Buildings and occupancies that require emergency lighting

The IBC requires emergency lighting for all buildings, with exceptions for Group U: utility buildings; Group R: dwelling units in residential occupancies; and Group I: sleeping units in institutional occupancies. When a building’s primary electrical supply is available, egress lighting must be served from that supply. When the primary supply fails, egress lighting in pathways that lead to

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exits, and exit discharges must be illuminated by an emergency power supply (IBC 1008.3). The emergency supply may take the form of an external generator, a central battery system or a distributed set of batteries serving individual luminaires.

The IBC’s requirements for emergency lighting are restricted to buildings that require two or more exits. Buildings requiring only one exit are defined in Table 1006.2.1 based on their occupancy types, occupant loads, common path of egress travel and whether they are sprinklered.

The requirements of NFPA 101 are similar, though expressed differently. Where the IBC provides a short list of buildings that do not require emergency lighting, NFPA 101 provides a long list of building occupancies in Chapters 11 through 43 and lists emergency lighting requirements for each. No emergency lighting requirements are described for one- and two-family dwellings or for rooming houses (Chapters 24 and 26, respectively). Some form of emergency lighting is required for all other building occupancies, often based on building height or number of occupants.

Both the IBC and NFPA 101 require exit signs, continuously illuminated, in all occupancies. The IBC lists exceptions for utility buildings, residential sleeping rooms and institutional sleeping rooms (1013.1). NFPA 101 lists requirements for exit signs in Chapters 11 through 43, describing exit sign requirements for individual occupancies. All occupancies other than one- and two-family dwellings and rooming houses show requirements for exit signs.

In general, the IBC applies to new buildings and renovated areas. New provisions are not normally enforced retroactively on existing buildings, except where an AHJ determines that existing conditions do not adequately provide for public safety (IBC 102.6). In contrast, NFPA 101 lists requirements for both new and existing buildings and is enforceable on all buildings in jurisdictions where it is adopted.

Where to locate emergency lights

NFPA 101 requires emergency lighting along all designated exit access components of the building including corridors, stairs and other passages that lead to an exit or from an exit discharge to a public way (7.9.1.2). “Designated components” refers to those exit pathways that are valid exit paths as determined by the AHJ. Excluded pathways that may well lead to outside the building are paths that are not legal for public exit including, for example, paths that lead through electrical or mechanical rooms or across ramps that are too steep. Requirements for the location of emergency lighting in the IBC are functionally identical to those of NFPA 101.

The IBC also requires emergency lighting in certain nonegress spaces to enable building personnel and emergency responders to support fire rescue efforts. Those spaces include fire command centers and rooms housing electrical equipment, fire pumps or generators. A requirement for emergency lighting in public restrooms larger than 300 square feet is included to facilitate egress for occupants unfamiliar with the room layout.

NFPA 101 and the IBC each require illuminated exit signs at exits and along egress paths, to visibly mark the various egress components in the building (NFPA 101 7.10.1.2; IBC 1013.1). Exit signs along egress paths must be located to ensure that an exit sign is within the lesser of 100 feet of any point along the paths or the listed viewing distance of the sign (NFPA 101 7.10.1.5.2; IBC 1013.1). In practice, all exit signs have a listed viewing distance of 100 feet. Neither code requires exit signs for main exterior doors that are obviously exits.

Both codes also contain provisions for exit signs installed near the floor level. The IBC references these signs for R-1 occupancies, such as hotels, outside sleeping rooms or dwelling units (1013.2). NFPA 101 describes similar signs and references

FIGURE 4: A battery-powered lighting unit in an exit stairwell. Courtesy: Johnston, LLC

Chapters 11 through 43 for occupancies where such signs are required (7.10.1.7). Low exit signs are currently required in special amusement buildings, a type of assembly occupancy, under NFPA 101, Assembly Occupancies.

NFPA 110 requires battery-powered lighting at generator set locations, other than in outdoor enclosures without walk-in access (7.3). Because the purpose of this lighting is to facilitate work on a failed generator, it cannot be supported by the generator alone. The battery’s charging equipment must be served from the load contact of a transfer switch. A similar, less extensive requirement appears in NFPA 99 (6.7.5.1.2.4(4)).

NFPA 99 requires battery battery-powered lighting where general anesthesia or deep sedation is used (NFPA 99 6.3.2.26.11). These luminaires are intended to continuously maintain a level of illumination where invasive procedures are performed, so that a surgeon performing a delicate procedure will not suddenly be left in total darkness should normal power fail and to provide minimal level illumination to allow the surgeon to terminate the procedure in the event that standby lighting fail to illuminate. These luminaires do not technically comprise emergency lighting, as facilities covered by NEC Article 517 have essential systems providing standby power and do not strictly have emergency systems.

Performance requirements per code

Typical performance requirements for emergency egress illumination are well-harmonized between NFPA 101 and the IBC. Power must be provided to emergency lighting within 10 seconds after a normal power outage (NFPA 101 7.9.1.3; IBC 2702.1.4). Emergency lighting must persist for 90 minutes after loss of normal power. The initial illumination along the egress path at the floor level must be an average of 1 footcandle (fc) and no less than 0.1 fc at any point.

After 1½ hours of continuous operation, Illumination must not decline below an average of 0.6 fc, with a minimum of 0.06 fc. The ratio between the maximum and minimum illumination levels along the path may not exceed 40 to one (NFPA 101 7.9.2; IBC 1008.3.4 & 5).

NFPA 101 specifically calls for new emergency lighting power systems to be at least Type 10, Class 1.5, Level 1 systems, as defined in NFPA 110

CASE STUDY: How to meet code and forgo emergency lighting outages

AN EXISTING

RESIDENTIAL FACILITY in Texas added a standby generator to serve its entire load during utility outages.

The facility was a 20-year-old independent living community, intended for generally healthy persons 55 years and older and capable of taking reasoned action for self-preservation. The NFPA 110: Standard for Emergency and Standby Power Systems occupancy was Chapter 30, Existing Apartment Building and the International Building Code occupancy was R-2, multiple dwelling units for primarily permanent residents.

No generator was required for this occupancy and none was initially provided. The facility included 240 residential units, kitchen and dining areas, office spaces and assembly spaces. The building was fully protected by an automatic sprinkler system.

Emergency lighting was provided in corridors, stairwells and other spaces where required using battery-powered lighting units. In corridors and assembly areas, those units consisted of downlights with batteries, along with equipment for battery status indications and test switches. In back-of-the-house spaces, such as stairwells, battery-powered strip fixtures were installed. Gypsum ceilings were installed in all public spaces.

The impetus for the addition of a whole-building generator was an extended power outage associated with a severe winter storm in 2019 in which residents evacuated with difficulty to temporary housing, which was locally in short supply. The facility contracted with an energy services firm to provide financing, design and construction for the project and to provide ongoing maintenance and management of the generator. The energy firm realized additional revenue from the generator’s participation in the local electric utility’s demand-response program by energizing the generator at the utility’s signal and transferring the building load from the utility to the generator to relieve the utility during power shortages.

The facility explored the option of installing the generator as a Level 1 system with an emergency transfer switch and a second, larger switch for optional loads. Under this option, it would be possible to move emergency lighting to the generator, eliminating a sizable number of luminaire batteries along with their associated maintenance burden.

However, the existing emergency lights had been installed on the same circuits as the normal lighting serving the area, as required for unit equipment (NFPA 70: National Electrical Code (NEC) 700.12(H)(2)(2)). To circuit the existing emergency fixtures to the generator would require opening and repairing almost a mile of gypsum ceiling and installing almost a mile of new circuit.

Establishing an emergency system would require a second transfer switch with bypass isolation (NEC 700.5(B), 700.5(F)) and a second generator breaker to achieve selective coordination, along with other equipment and wiring. The simple expedient of connecting all the lighting in egress paths to the emergency system was precluded by the specific NEC prohibition against serving any lamps other than those required for emergency use (700.15).

The existing emergency lighting was left in service. The generator was installed to serve optional loads, with a single transfer switch for the entire building load. The existing emergency lighting system remains in place with its attendant maintenance requirements. In practice, batteries provide illumination for only a few seconds after loss of utility power until the generator restores power to the building

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FIGURE 5: Unit equipment in the corridor of a residential occupancy. This unit is normally not illuminated and automatically comes on when normal power fails. Courtesy: Johnston, LLC

(7.9.2.2). NFPA 110 identifies a Level 1 system as one whose failure could result in death or severe injury to humans. System type is defined as the maximum time, in seconds, that the emergency system may be without power. System class is defined as the minimum time that the system will serve rated load without refueling or recharging (4.1).

The NEC requires that storage batteries and uninterruptible power supply systems that support emergency lighting systems maintain their output voltage at 87.5% of nominal for 90 minutes (700.12)

least 90 minutes after normal power fails. The two codes instead focus on physical characteristics of the signs and their listings. The IBC permits only the legend, “EXIT,” on exit signs (1013.6.1). NFPA 101 requires that same legend, but permits “other appropriate wording,” and allows for use of pictograms from NFPA 170: Standard for Fire Safety and Emergency Symbols with AHJ approval (7.10.3).

Testing and maintenance requirements

Testing requirements for emergency lighting are found in NFPA 101. Testing may be performed manually or by an automatic system. Written records of testing are required, generated manually or automatically, depending on the test method employed (7.9.3.1). Functional testing is required monthly for at least 30 seconds with the equipment under test fully functional.

Emergency lighting insights

u Electrical and life safety engineers must understand NFPA 101: Life Safety Code to ensure emergency lighting systems provide adequate illumination for safe egress during power outages or emergencies.

u The code outlines specific requirements for placement, duration and intensity of emergency lighting to meet life safety standards in various building occupancies.

u This article surveys some of the more popular codes, providing references for key provisions governing emergency lighting installations. Applicability of specific codes will depend on adoption by local jurisdictions.

Emergency illumination requirements for stairways are subject to interpretation under NFPA 101. Emergency illumination requirements provide specific levels for the egress path, but do not mention stairways (7.9.2.1.1). Section 7.8, Illumination of Means of Egress, requires that stairs be illuminated at 10 fc "during conditions of stair use." Requirements in 7.8 are higher than those covering emergency lighting in 7.9, suggesting — but not directly stating — that illumination levels described in 7.8 cover requirements for lighting under normal power conditions.

AHJs have attempted to enforce the 10-fc rule on emergency lighting in stairways. Where generators provide emergency power, compliance with such a rule is not difficult because emergency lights operate at full illumination on generator power.

Battery-powered lighting units, on the other hand, operate at a fraction of their normal lighting level on emergency power, making compliance with a 10 fc rule difficult or unreasonable.

The IBC and NFPA 101 say little about performance requirements for exit signs, except to note that they must remain adequately illuminated to be seen from their listed viewing distances for at

For manual tests of battery-powered lighting units, an operator will press a button at or near the luminaire that disconnects the luminaire from normal power and connects it to its battery for as long as the button is depressed. Longer functional tests are required annually, for a period of 90 minutes. For these tests, lighting circuits are typically de-energized and personnel observe adequate function throughout the test area.

For generator-based systems and stored battery systems, NFPA 101 states that testing “shall be permitted to be conducted in accordance with 7.9.2.4” (7.9.3.1.4). The referenced section states that generators and appurtenances serving emergency lighting shall be installed and maintained in accordance with NFPA 110 and stored energy systems in accordance with NFPA 111.

Testing and maintaining those systems as described in their respective codes would meet the testing requirements of NFPA 101 for emergency lighting systems, whether illumination levels were tested or observed. It’s not entirely unlikely, though, that an AHJ would require that emergency luminaires themselves be assessed connected to the emergency power system and their proper function observed and recorded.

NFPA 110 and NFPA 111 each describe requirements for initial acceptance testing (NFPA 110 7.13; NFPA 111 7.6) and for routine maintenance and operational testing (NFPA 110 8; NFPA 111 8). A detailed description of testing requirements

is too lengthy to present here. Acceptance testing requirements are highly prescriptive, requiring several inspections, at least two rounds of load testing and logging of system performance and conditions.

In broad terms, maintenance testing requirements for generator systems call for monthly load testing with 30% load, with the exhaust at the manufacturer’s recommended operating temperature and with additional testing where those parameters can’t be achieved (NFPA 110 8.4.2.1). NFPA 111 does not directly prescribe load testing procedures for storage battery systems, deferring to the system manufacturer’s recommendations (8.4.1).

Does the electrical system include emergency lighting?

The installation requirements for power systems serving emergency loads, including emergency lighting, appear in NEC Article 700, Emergency Systems. These requirements cover all the loads of the emergency power system, including emergency lighting. This section focuses on those requirements that most directly affect emergency lighting.

Note that health care facilities technically don’t have an emergency system; however, their life safety branch falls under Article 700, except where amended in Article 517 or in NFPA 99 (NEC 517.26; NFPA 99 6.7.6.2.1.5).

Article 700 requires that emergency system wiring be entirely independent of all other wiring (700.10(B)), with limited exceptions. Those exceptions are necessary to implement the intended transfer operations of the system or to bring the wiring to a point in the standby system where the emergency system originates. Emergency wiring and other wiring may enter the same enclosures of transfer switches and similar equipment that selects between available sources (700.10(B)(1)-(4)) and it may originate in the same distribution equipment as other circuits provided that a degree of separation is maintained. Emergency lighting and power circuits may serve none but required emergency loads (700.15).

The emergency system capacity must be adequate to serve all the loads connected to the system simultaneously, as calculated by one of the methods described in Parts I through IV of Article 220: Branch-Circuit, Feeder and Service Load Calculations. The system may serve nonemergency loads

‘Testing and maintaining those systems as described in their respective codes would meet the testing requirements of NFPA 101 for emergency lighting systems, whether illumination levels were tested or observed.’

as well, if it has “adequate capacity,” or a load shed system to selectively shed other loads in favor of the emergency system (700.4(B)).

Essential systems for health care facilities are not required to be sized for Article 220 load calculations. Instead, those systems must have adequate capacity to meet the actual demand presented by their connected loads (NEC 517.31(D); NFPA 99 6.7.1.2.4).

Overcurrent protection devices on the emergency power system must be selectively coordinated with all upstream devices. The definition of "selective coordination" in the NEC is quite strict, requiring coordination for the "full range" of overcurrent settings and device operating times. In a typical standby generator system serving optional load along with emergency load, the optional load will be many times larger than the total load of the emergency system, making selective coordination difficult.

For single generator systems, it is permissible to install a separate circuit breaker to serve emergency system at the generator terminals, obviating concerns about upstream coordination. In health care facilities, selective coordination is required only for faults that persist longer than 0.1 seconds (NEC 517.31(G); NFPA 99 6.7.2.1.1).

Emergency system feeders and generator control circuits must be protected from fire by one of several methods in large assembly occupancies, large educational occupancies and high-rise buildings (700.10(D)). For health care occupancies, this requirement does not apply (NEC 517.26(2); NFPA 99 6.7.6.2.1.5(B)(2)). Feeder-circuit equipment must be in rooms with either a two-hour fire rating or fire sprinkler protection. cse

Tom Divine, PE, is a senior electrical engineer at Johnston, LLC. He is a member of the Consulting-Specifying Engineer editorial advisory board.

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Danny DeGennaro, EIT, CDM Smith, Latham, NY

Ian Smith, PE, CDM Smith, Fairfax, VA.

Back to basics: Microgrids and renewable energy

Microgrids can help system owners meet the special considerations necessary to integrate intermittent renewable power sources into power systems while enhancing electrical system reliability and resiliency.

NFPA 70: National Electrical Code (NEC) 2023 defined microgrids as “an electric power system capable or operating in island mode and capable of being interconnected to an electric power production and distribution network or other primary source while operating in interactive mode, which includes the ability to disconnect from and reconnect to a primary source and operate in island mode.” Microgrids can play a crucial role in integrating renewable energy sources into facilities while maintaining facility reliability, as they are inherently scalable and flexible. They may be small and only consist of a few system components, or they can be made up of an entire complex campus of different buildings and generation sources. Microgrids can operate in either grid-connected or islanding mode. Stand-alone or isolated microgrids have no utility connection and serve only as offgrid power systems.

• Islanding: Using on-site distributed energy resources (DER) to provide power to a facility when disconnected from utility power.

• Renewable smoothing: Using an energy storage system (such as batteries) to reduce the effect of intermittent renewable energy generation.

• Peak shaving: Reducing electrical power consumption by using on-site distributed generation during periods of maximum demand on the utility.

• Scheduled power: Monitoring the energy market to determine when it would be more cost-effective to use on-site distributed generation to power facility loads in place of only the utility source.

• Voltage and frequency regulation: Adjusting DER outputs to provide near-constant voltage and frequency regardless of changing load conditions. By leveraging these features, microgrids can facilitate integration of intermittent renewable energy sources while enhancing the reliability and sustainability of the overall power system.

Microgrid main components

Microgrids are composed of several key components that work together to manage energy flow through a power system. Some main components include:

• Energy sources: Devices which produce energy on-site from DER, such as solar panels, wind turbines, diesel generators and fuel cells.

• Energy storage: Batteries and other storage systems, like flywheels, that store excess energy for use when available generation is low or demand is high.

• Understand the components and basic operating principles of microgrids.

• Review the design criteria of solar photovoltaic (PV) and battery energy storage systems (BESS).

• Understand how to integrate PV and BESS into existing power systems to form a microgrid.

Microgrids must function as a single controllable entity to accomplish the objectives set out by the system owner, whether that is improving resiliency, decreasing dependence on the grid, maximizing the benefit of renewable energy sources, maximizing economic payback or a combination of these. Some common microgrid power management techniques and uses are listed below.

• Microgrid controllers: The “brains” of the microgrid, including supervisory control and data acquisition (SCADA) systems and energy management software that balance supply and demand, optimize performance, ensure stability and make decisions on when to operate in islanded or grid-interactive mode.

• Distribution infrastructure: This includes the electrical cables, transformers, inverters and switchgears that connect generation sources to consumers and manage the flow of electricity. At the beginning of any project, the designers must review and evaluate which energy

generation technologies might be best suited for the site. Designers must identify the project objectives and how much energy is required to meet the system requirements. Certain technologies may not be viable because of space, available solar or wind resources, or other geographical constraints.

Microgrid controllers play a crucial role in managing and optimizing microgrids to meet their target objectives. A microgrid controller functions as the top-level manager of the microgrid and coordinates the various components to ensure efficient operation and proper transitions between different modes of the microgrid operations for both grid-connected and islanding modes.

As renewable energy and other DER are increasingly deployed, microgrids will continue to play a key role in ensuring power system reliability and maximizing the benefits that DER can provide. The most common microgrid components are photovoltaic (PV), battery energy storage systems (BESS) and engine-driven generators.

Solar photovoltaic systems

Solar PV technology converts sunlight directly into electricity using the photovoltaic effect and is a common and cost-effective DER option. NEC Articles 690 and 691 cover general requirements for PV systems, both small scale and large scale. NEC Article 710 covers requirements for PV systems that operate independently from the grid.

Some key components of PV systems are listed below:

• PV modules/panels: PV cells are the basic units of modules/panels and use specific semiconductor materials. Busbars and diodes link cells together in series and parallel to form collection grids housed together in a single frame with the desired output voltage and current ratings.

• String: Module direct current (DC) outputs are electrically connected in series to form a string. Multiple strings can be paralleled in combiner boxes.

• Inverters: Convert the DC power output from PV modules to alternating current (AC) electricity.

• Racking systems: Securely hold PV modules and other equipment in place.

• Wiring: Interconnects PV modules, inverters and other system components.

• Array: A mechanically and electrically integrated set of the above components is called an array.

FIGURE 2: An example roof-mounted PV array. Panels are oriented due south and integrated using a string PV inverter to convert from DC to AC power. Courtesy: CDM Smith

There are many PV module technologies available, each optimized for different applications. Three well-developed and commonly deployed PV module technologies are listed below.

• Monocrystalline silicon: Single crystalline silicon (c-Si) substrate. Its uniform structure yields higher efficiency rates and longer life span but has higher initial costs.

• Polycrystalline silicon: Silicon substrate with many different crystals. It is easier to manufacture and less expensive than c-Si, but has lower efficiency.

• Thin-film: A category of semiconductor substrates that are very lightweight and flexible. Often lower efficiency than c-Si options. Common thin film materials include Cadmium Telluride, Copper Indium Gallium Selenide, Amorphous Silicon or Gallium Arsenide.

There are three common PV inverter configurations: micro, string and central. Micro configurations convert the electricity from a single PV module from DC to AC. These are typical for residential installations. String configurations convert the electricity from a group of PV modules (or string) from DC to AC. They are typical for commercial/industrial installations. Central configurations convert the electricity from an entire PV array from DC to AC with one centralized inverter. They are suitable for certain commercial/ industrial installations.

Micro-inverters provide the most resilient and costly option, since the output of the system is not greatly affected by the performance of a single module or inverter. Micro-inverters are easiest to integrate with a small number of modules. String inverters often lower the cost and simplify the

‘As renewable energy and other distributed energy resources are deployed, microgrids will continue to play a key role in ensuring power system reliability.’

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‘

BESS can strategically charge and discharge to synchronize energy production from intermittent renewable energy sources with demand.

’

design in systems with larger numbers of modules. Central inverters may be preferable for large systems. Central inverters also have advantages when designing a microgrid system, as it is easier to integrate a smaller number of components. However, central inverters provide a single point of failure and can struggle to efficiently handle constantly changing shadow profiles over the entire array.

PV arrays can be building-mounted, ground-mounted, or canopy-mounted and must be designed for all applicable structural loads.

Battery energy storage systems

BESS can store electrical energy from various w sources and discharge it when required by using energy management strategies. NEC Article 706 covers general requirements for energy storage systems, including batteries. NEC Article 480 provides guidelines for the installation and maintenance of storage batteries.

BESS can strategically charge and discharge to synchronize energy production from intermittent renewable energy sources with demand. Sometimes referred to as renewable smoothing, this reduces the effect of renewable energy power fluctuations. Two common designs for BESS are container configurations and cabinet configurations.

For large systems, containers can be paralleled together to meet the desired energy capacity. This can be accomplished through traditional parallel-

ing switchgear or by using a microgrid controller or similar device designed to integrate multiple power sources.

Two prevailing battery chemistries for energy storage applications are lithium nickel manganese cobalt oxide (NMC) and lithium iron phosphate (LFP). NMC and LFP are both types of lithium-ion chemistries. LFP is more common in stationary applications than automotive applications, partially because of its heavier battery chemistry. However, it is much more difficult to make an LFP cell go into thermal runaway than an NMC cell, making it a great option where fire safety is a concern.

Although NMC batteries have a higher energy density (kWh per pound), LFP has emerged as the industry-leading energy storage chemistry for stationary applications, due to its thermal stability/ safety and its reduced reliance on rare metals.

Generators

While conventional generators use fossil fuels and are considered a nonrenewable energy source, they can play a crucial role in filling in gaps between renewable production and demand in microgrid systems, particularly when demand cannot be met with BESS or another means of renewable energy storage. NEC Article 445 covers generator installation requirements. NEC Articles 700, 701, and 702 cover requirements for generators used in emergency systems, legally required standby systems and optional standby systems, respectively.

The main considerations when selecting a generator as part of a microgrid are the fuel type, size and emissions rating. Two widely used generator fuels are natural gas and diesel. Some key characteristics of the two fuel types are listed below.

Natural

gas generators:

• Cost-effective fuel source, but not always accessible.

• More environmentally friendly, less pollutants and odor.

• Less energy dense fuel source, larger system footprint.

FIGURE 4: A skid-mounted natural gas generator. The gas engine creates rotational mechanical power, which is converted to electrical power by the alternator. Courtesy: CDM Smith

• Does not typically experience wet stacking.

• No on-site fuel storage (dependent on external utility).

Diesel generators:

• More expensive fuel source, but also more accessible.

• Less environmentally friendly, some pollutants and odor.

• More energy dense fuel source, smaller system footprint.

• Can experience wet stacking when underloaded.

• Fuel storage on-site (fuel deliveries required for continued operation).

Additionally, engineers must consider the emissions rating. Generators rated for stationary emergency applications can participate in the microgrid only when utility power is unavailable. While acceptable for microgrids focusing on resiliency, microgrids with the goal to perform peak shaving or another utility-interactive activity may require a generator rated for stationary nonemergency use.

Integration and interconnection

Utility interconnection requirements allow transparent communication between all parties involved for public and personnel safety and for power performance requirements. Utilities must be involved during the project planning or design stages to determine the feasibility of interconnection and to ensure requirements are met.

PV systems and BESS, which have DC power outputs, are sometimes referred to as inverter-based resources (IBR). For BESS, inverters must be bidirectional to allow the batteries to both be charged and to supply power to the electrical system.

In general, inverters can operate in either grid-forming mode (acts as a voltage source) or grid-following mode (acts as a current source). A grid-forming source is required when islanding, and grid-following mode is used when the inverter is not the primary power source.

Inverter behavior during external power outages, also called the inverter ride-through feature, is important for overall grid stability, especially as IBR become a larger portion of overall power generation resources. Codes and standards that govern inverter ride-through requirements include UL 1747, IEEE 1547 and IEEE 2800. These standards require inverters that back-feed the grid must not instantaneously go offline upon a momentary utility outage. Specific requirements set by the utility will impact inverter and microgrid controller specifications.

5: An example of a microgrid paralleling switchboard one line diagram. The microgrid controller electrically operates the circuit breakers and monitors power flow with power quality monitors.

Courtesy: CDM Smith

FIGURE

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‘When selecting the power rating of the BESS, the main consideration is the goal of the microgrid system.’

The NEC also has specific connection requirements pertinent to microgrid systems. NEC 2023, Article 705 covers the installation of one or more electric power production sources operating in parallel with a primary source or sources of electricity. When DER are integrated into an existing system, careful attention must be paid to the requirements of Article 705 to ensure that power distribution equipment is not overloaded by multiple power sources.

Additionally, cybersecurity considerations also impact the inverter and controller design, including what communications protocols are used (wired vs. wireless) and where sensitive communications equipment is located. Designers must consult with cybersecurity experts to mitigate the risks of cyberattacks in sensitive facilities.

Solar photovoltaic system sizing

The first step in sizing any PV system is considering the energy demand of the associated facility or facilities. Collect historical energy consumption data from utility bills for at least one year to understand energy use patterns. Consider the average daily peak sun hours (PSH) for the project region. The National Renewable Energy Laboratory has libraries of solar resource data, tools and maps to obtain these numbers and guide this process.

The goals of the system will also impact sizing. The goal may be to offset the full energy consumption of the facility or a certain percentage of it. Financial goals such as maximizing return on investment or payback period may also dictate a certain system size.

Efficiency losses from inverters or resistive losses in the wiring should be considered. Other site-specific losses, such as temperature losses or shading, are not factored into the regional PSH number but should also be considered. Approximate shading analysis and temperature-based losses can be performed with software by modeling approximate sizes of adjacent buildings and. Detailed shading or other loss analysis can be difficult without thorough data collection.

Battery energy storage system sizing

There are two primary considerations when sizing BESS: the power rating (kW) and energy storage capacity (kWh).

When selecting the power rating of the BESS, the main consideration is the goal of the microgrid system. If the goal is to power the entire facility in the event of a power outage without using any other resources, the BESS must be sized for the facility’s peak demand. If the goal is to only power critical loads, the BESS should be sized for the peak demand of those loads.

The selection of the BESS energy storage capacity also depends heavily on the microgrid goals. For resilience, a common goal is to have a desired run-time for the facility without utility or other power sources (two and four hours are common target run-times). The minimum BESS capacity can then be selected by either multiplying by the peak or average hourly energy consumption. Using the peak hourly energy consumption guarantees that the BESS will support the facility for the selected run-time, if starting fully charged. If the energy storage capacity is instead selected based on the average hourly energy consumption, in periods of high electrical demand the BESS may not support the facility for the full duration of the run-time. If the goal is to perform other energy management techniques, such as peak shaving or renewable smoothing, the BESS sizing may be more complicated and require more detailed analysis.

Real-world scenario

Consider a scenario where a local school requires upgrades for a backup power source, as it has just been identified for use as an emergency shelter in the event of a natural disaster. The school board aims to integrate renewable energy into these upgrades, cost permitting. The school’s energy bills for the last year were collected, and it was determined that the peak demand was 390 kW and that over the year the school used 1,752,000 kWh of energy.

The goal of the PV system will be to fully offset the annual energy consumption. The school receives 4.1 peak sun hours daily, or 1,496.5 peak sun hours per year. Dividing 1,752,000 kWh by 1,496.5 hours yields a target DC nameplate value for the PV system of approximately 1,170 kW. At this point, equipment selections for the PV modules and inverters are made by considering PV module efficiency and size for the application and match the inverter capacity (either string, central or

micro) to at least 80-90% of the target system size. String inverters are selected given they are cost-effective and do not consolidate to one failure point. Dividing the target system size in kW by the PV module nameplate DC kW rating yields the quantity of modules required. For the selected 400 W modules, this system requires at least 2,925 PV modules to reach the target 1,170 kW nameplate capacity.

The final step is to design the system layout based on available space. This can be approximated with satellite imagery but is best performed with a site survey. The tilt angle of the PV modules and module orientation is set based on the latitude to directly face the sun at solar noon on the average day. The module quantity, module racking, row spacing and maintenance clearances inform the layout and overall array footprint.

The electrical system layout is designed to include wiring, conduit runs, combiner boxes and connection points. At this point, a cost estimation is performed to determine the project's viability. Detailed energy production is simulated based on local weather data using software tools, and the

utility energy buyback rates and other rate structure is considered, alongside available government subsidies and incentives.

Consulting with the local emergency planners determined that the whole school is expected to be used during worst-case natural disasters. Based on this, the BESS was sized, at minimum, for the peak demand of the whole facility. Based on the 390 kW peak demand, this allows the whole school to be powered on the BESS and ensures that immediate islanding can be provided if the utility power fails.

When deciding the method to determine the minimum energy capacity of the BESS, several factors were considered. First, a substantial portion of the power demand is for air conditioning, and when the air conditioning demand is highest, significant solar power will also be generated by the solar array. Secondly, it was considered that a guaranteed source for critical power loads (an existing engine-driven generator) is available. These factors determined that some redundancy exists in the system, so the BESS will be sized based on average energy usage for four hours. Based on the utility

‘The final step

is to design the system layout based on available space. This can be approximated with satellite imagery but is best performed with a site survey.

’

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BUILDING SOLUTIONS

Microgrid insights

u Microgrid solutions are site-specific, requiring careful assessment of energy needs and financial feasibility.

u Battery energy storage enhances grid independence and reduce reliance on fossil-fuelbased generators.

bills, the hourly average energy demand is 200 kW, and it was determined that correspondingly the minimum BESS energy capacity is 800 kW per hour.

From the calculations above, a commercially available 500 kW/1000 kWh container-style BESS system was selected as the basis of design to participate in the new microgrid system. Similar to the PV system, a financial analysis is needed to determine whether include BESS is cost effective. The utility rate structure has a widespread based on time of use, and the primary method for the BESS to pay for itself is found to be through peak-shifting and charging during off-peak rates.

To tie the microgrid together, the solar PV system, BESS and existing generator must be interconnected. Space is limited in the existing electrical room, so a new switchboard was chosen to be installed outside where all DERs will be connected. To integrate the existing loads, the new switchboard was “inserted” between the existing service equipment and the utility transformer. This way, construction and disturbanc-

es inside the existing school and electrical room are minimized. The circuit breakers for the utility and DERs in the new switchboard are electrically operated and controlled by the microgrid controller, which allows it to manage the resources in real time and ensure that a constant source of power is available. Additionally, as an extra safeguard, the critical loads identified while sizing the battery were moved to their own breakers on the new switchboard so that non essential loads can be shed if limited power is available. cse

Danny DeGennaro, EIT, CDM Smith, Latham, NY. Danny DeGennaro is an electrical engineer at CDM Smith focused on industrial power system design and emerging energy technologies.

Ian Smith, PE, CDM Smith, Fairfax, VA. Ian Smith is an electrical engineer at CDM Smith focused on power system design and protection including medium and low voltages as well as communications and SCADA systems.

24_014588_Consulting_Specifying_Engineer_MAR Mod: January 21, 2025 9:07 AM Print: 01/27/25 page 1 v2.5

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ENGINEERING INSIGHTS

Focus on nontraditional learning spaces in K-12 building design

K-12 school buildings are often seeking more flexibility to provide unique learning paths for students.

CSE: What are the current trends in K-12 school projects?

Raquel Deschler: Lately we've seen a rise in career technical education (CTE) facilities for high schools. These programs prepare students for careers that require both academic and technical skills. The hands-on courses are typically electives taught by instructors that have industry experience and apply lesson plans to real world projects. RMF is designing health sciences classrooms, as well as mechatronics, welding and automotive laboratories.

The flexibility of being exposed to and learning these trades while still in high school allows students to see all of their options, potentially find a passion outside of a traditional college setting and, hopefully, be more successful in the workforce.

Scott Peck: A trend I’ve seen in the past few years is that districts are building and operating child care centers. Districts have started doing this for several reasons, with one being that it is a revenue stream for the district, as parents/caregivers must pay for their children to attend.

Without an in-district child care center, parents/caregivers may send their child to a neighboring district’s program, directing that revenue stream elsewhere. In some instances, once a child is ready to start the K-12 curriculum, both parents and students have established friendships within the neighboring district's child care program. In Michigan particularly, parents/ caregivers have the choice to send their child to neighboring school districts for their K-12 curriculum, allowing them to stay with the friends they have made. Per-pupal funding from the state follows the student, so the neighboring district now receives the state funding for that student.

Zachary Schneider: High performance learning environments are becoming more and more important to owners. This encompasses numerous items that build upon one another, including a healthy indoor environment. This is achieved with increased ventilation rates which reduce carbon dioxide, natural daylighting with minimal glare and efficient artificial lighting that helps with circadian rhythm. Efficient heating, ventilation and air conditioning (HVAC) systems drive energy use down to as low of an energy use index as possible, saving hundreds of thousands of dollars per year for districts that they can reallocate back into the students and staff. These systems, such as a ground source geothermal heat pump system, also help the maintenance staff due to the ease of maintenance.

FIGURE 1: John Lewis Elementary School sets a new bar for sustainable projects as a triple-certified building, achieving LEED Platinum, Zero Energy and WELL Platinum certifications. Courtesy: CMTA, Inc.

Raquel Deschler, PE, Project Manager, RMF Engineering, Charleston, S.C. Scott Peck, PE, Vice President, Peter Basso and Associates, Troy, Mich.

CSE: What future trends should engineers expect?

Scott Peck: We are starting to see more districts adding science, technology, engineering and mathematics spaces within their buildings. These tend to be larger open spaces that are configurable by the end users. The furniture is designed to be flexible, along with extra receptacle and technology elements in the space. Often, cord reels are preferred over floor boxes. The cord reels are in a set pattern, allowing for use in many different room set ups.

Zachary Schneider: I expect a push toward more efficient building practices and energy usage, with a clear focus on achieving carbon-neutral and zero-energy outcomes. Building owners are prioritizing the reduction of carbon emissions and energy consumption to minimize operational costs, allowing integration of renewable energy solutions to create zero-carbon, zero-energy facilities. By implementing efficient design strategies, optimizing system sizing to fit specific spaces and leveraging clean energy tax credits, high-performance systems can often be more cost-effective than traditional systems.

CSE: Tell us about a recent project you’ve worked on that’s innovative, large-scale or otherwise noteworthy. Please tell us about the

location, systems your team engineered, key players, interesting challenges or solutions and other significant details.

Raquel Deschler: RMF is currently working with Liollio Architecture and Brownstone Construction Group on finalizing Charleston County School District's new Early College High School, which is slated to open in March of 2025. The project is in downtown Charleston on the site of the historic former Wilmot J. Fraser Elementary School. The school was originally constructed in 1957 as part of South Carolina’s equalization program, which was intended to provide separate but equal facilities for African American students. The facility continued to support the community through segregation and still plays an important role in the lives of those who live there. To pay homage to the community, the school's front facade was preserved, with a new facility built behind it to meet current codes and standards. The original school, of course, was not built for modern ductwork, fire protection distribution or current seismic requirements, so keeping the facade posed several challenges.

The design team closely collaborated to ensure the structure, mechanical, electrical and plumbing systems could work within the tight ceiling space so that Liollio was able to respect the original building brick detailing, windows and entry.

Zachary Schneider: CMTA has over 140 million square feet of K-12 design experience across the country. One of the many to highlight would be John Lewis Elementary for the DC Public Schools. This is a new, 88,599 square foot elementary school, and with the district’s ambitious energy and carbon reduction goals, we were able to design their first Zero Energy, LEED Platinum and WELL Platinum certified school. This design included a geothermal HVAC system, dedicated outdoor air ventilation system and a 650 kilowatt solar voltaic system.

CSE: How are engineers designing these kinds of projects to keep costs down while offering appealing features, complying with relevant codes and meeting client needs?

Objectives Learningu

• Understand what flexible spaces or other unique demands K-12 buildings have compared to other designs.

• Identify how specific learning paths and spaces create challenges for design engineers.

• Learn what trends engineers should be expecting in the coming years regarding school buildings.

Zachary Schneider, PE, LEED AP, CxA, LC, Partner/Electrical Engineer, CMTA, Inc, Louisville, Ky.

FIGURE 2: Modular furniture in this library demonstrates schools’ desire for more flexible learning spaces. Courtesy: RMF Engineering

ENGINEERING INSIGHTS

Scott Peck: One of the best ways to keep costs down while meeting the client’s needs, is to work closely with the district’s facility manager to have a solid understanding of their expectation for the performance of mechanical, electrical and plumbing systems. It’s also important to understand their maintenance budget and capabilities, as many facility directors are being asked to do more with less staff and budget. With this knowledge, the engineering team can work with the district to come up with solutions that will meet their needs now and in the future. This is often accomplished by making the choice to pay more up-front for a higher quality piece of equipment or feature, which will ultimately pay dividends later with reduced maintenance costs as opposed to going with the lowest initial install cost. No matter what system is chosen, it must comply with all relevant codes.

Zachary Schneider: Engineers are designing these projects by focusing on collaboration and efficiency. It all starts with close coordination between architects, owners Sand contractors to ensure everyone is aligned toward the same goal. A key step is optimizing the building’s orientation to reduce solar load and maximize daylighting. Engineers also work closely with architects to design a highly efficient building envelope with proper air tightness and R-values. This minimizes energy loss, allowing systems to be “rightsized,” which reduces both costs and longterm operational expenses. Additionally, by leveraging direct rebates from clean energy tax credits, these facilities can often be built at the same or even lower costs than traditional designs.

Automation, Controls and Technology

K-12 insights

uSchool districts are increasingly integrating flexible spaces and high-performance learning environments that focus on energy efficiency, carbon reduction and student well-being.

uCollaborating with architects, owners and school districts can help create the most costefficient and energy-efficient building.

CSE: How is your team using building information modeling (BIM) in conjunction with the architects, trades and owner to design a project?

Raquel Deschler: BIM is an incredibly useful tool for getting various project partners on the same page, but it has its limitations. If something like the electrical switchboard is shown as 2D lines, as

opposed to modeled as a 3D object, the equipment may not fit through the door that the architect provided for the room. It's important that the team stays in communication during the entire process to avoid these situations, which ultimately can lead to project delays and budget overages. This is especially the case for K-12 projects, which often work on a tight schedule to ensure the building is finished in time for the start of a new semester.

Scott Peck: Revit is used for design assist in several instances such as airflow accumulation, electrical load circuiting, hydronic flow accumulation, domestic water sanitary and vent fixture units’ accumulation, clash detection and roof drainage system sizing. It is also used as a quality control tool for the following: electrical circuit review for overloads, load balancing, identification of missed/un-circuited loads, mechanical terminal unit inlet diameter vs airflow checks and unit length, diffuser neck size check and for verifying motor brake horsepower does not exceed 90% of horsepower rating.

Zachary Schneider: BIM has proved to be a valuable tool for coordination and conflict prevention during construction. However, it’s important to recognize its limitations. While accuracy in the model is essential, field conditions, equipment manufacturing variations and installation challenges can still arise once the building is under construction. These factors cannot always be fully anticipated in the model. Effective collaboration among contractors in the field remains critical. No matter how precise the model is, close coordination during the construction process will always play a vital role in ensuring the success of the project.

Codes and Standards

CSE: Explain some of the codes, standards and guidelines you commonly use during the project’s design process. Which codes/standards should engineers be most aware of?

FIGURE 3: Child care spaces in K-12 schools require conversations with school districts early in the design phase. Courtesy: Peter Basso Associates

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ENGINEERING INSIGHTS

Scott Peck: There are several electrical codes and standards that are commonly used. NFPA 70: National Electrical Code (NEC), is most commonly used, so engineers should be the most familiar with NEC. They should be aware of all codes in a particular project including: NFPA 101: Life Safety Code, NFPA 72: National Fire Alarm and Signaling Code, ASHRAE Standard 90.1: Energy Standard for Buildings Except Low-Rise Residential Buildings and state level codes.

CSE: What new code/standard have local jurisdictions adopted to meet COVID-19, RSV or other health guidelines? What updates do you anticipate if none have been adopted yet?

Raquel Deschler: School districts were using the indoor air quality procedure from ASHRAE Standard 62.1: Ventilation for Acceptable Indoor Air Quality long before COVID. This method allows you to offset the amount of outside air circulation needed by using an air purification system, such as bipolar ionization, in lieu of the traditional ventilation rate procedure (VRP). This was, and still is, an important energy saving strategy for the districts. After COVID, the focus has shifted to achieving both meeting or exceeding traditional VRP methods while also providing additional filtration systems above the standard requirements.

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CSE: How are codes, standards or guidelines for energy efficiency impacting the design of K-12 schools?

Zachary Schneider: The adoption of the latest IECC by more states is driving significant changes in school design. The latest IECC emphasizes improved lighting design, better daylighting strategies and plug load controls, among other measures. These updates are helping schools enhance energy efficiency throughout their buildings, creating more sustainable and cost-effective learning environments.

CSE: What are some of the biggest challenges when considering code compliance and designing or working with existing buildings?

Scott Peck: When working in existing buildings it is not uncommon to come across installations that are not compliant with the current codes. Equipment for a system you are not upgrading or renovating is generally "grandfathered in" and no changes are needed. The problem becomes a much larger issue when there are existing code compliance issues with a system you are modifying or adding to. There is the saying, “if you touch it, you own it;” meaning if you are modifying or adding to a system you must bring at least that part of the system up to current codes. This can snowball and lead to many required changes that may or may not have been known when the budget was established.

Zachary Schneider: Establishing a strong working relationship with the local authority having jurisdiction (AHJ) is essential when undertaking a renovation in an existing building. Renovation projects often present unique challenges that may not be explicitly addressed in code references. Collaborating closely with the AHJ through site visits, identifying specific issues and developing solutions that balance code compliance with client needs has proved to be an effective and valuable approach.

CSE: What new code/standard have local jurisdictions adopted to meet COVID-19, RSV or other health guidelines? What updates do you anticipate if none have been adopted yet?

Raquel Deschler: School districts were using the indoor air quality procedure from ASHRAE Standard 62.1: Ventilation for Acceptable Indoor Air Quality long before COVID. This method allows you to offset the amount of outside air circulation needed by using an air purification system, such as bipolar ionization, in lieu of the traditional ventilation rate procedure (VRP). This was, and still is, an important energy saving strategy for the districts. After COVID, the focus has shifted to achieving both meeting or exceeding traditional VRP methods while also providing additional filtration systems above standard requirements. cse

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