Consulting Specifying Engineer March April 2026

S17 Centum™ Series The complete spectrum of power.

Revolutionary power generation is here. The S17 Centum™ Series provides up to 1000 kW of high-performance, cost-efficient power. With an advanced fuel system and optimized cylinder and coolant flow design, it’s ready to meet the challenges of today and the future. Backed by 25,000 hours of testing – you can be sure it will deliver under pressure.

Scan to find out more

Creating a life safety strategy

NEWS &BUSINESS

3 | Fire, life safety considerations for office-to-residential conversion

During conversion from office space to residential units, fire protection engineers must consider many life safety factors.

BUILDING SOLUTIONS

4 | Alarm fatigue and life safety: Improving fire notification

A fire alarm that meets code but fails to prompt immediate action can lead to catastrophe.

12 | Surviving survivability: A guide to life safety pathway survivability

A focus on fire alarm, smoke control and low-voltage life safety system circuits shows electrical system survivability requirements.

20 | Practical applications of AI in engineering design

Use this framework to leverage artificial intelligence to safely support the engineering design process under human governance.

ON THE COVER:

A combination fire alarm notification appliance (speaker and strobe) in an open office environment can be challenging. In this instance, there are numerous potential obstructions that could impact line-of-sight visibility for the occupants. This image also illustrates the additional junction box depth required to accommodate the speaker cone, which won’t fit in a typical 2.125-inch deep junction box. Courtesy: McGuire Engineers 4

28 | Make lighting control design smarter with a cognitive walkthrough

Lighting control technology has evolved from analog to digital tools with a focus on smarter, more sustainable and humancentered lighting solutions.

34 | Understanding ASHRAE 90.1’s role in energy codes and regulations

ASHRAE Standard 90.1 is an energy efficiency standard often referenced in the International Energy Conservation Code. Learn to navigate both for building energy standards.

ENGINEERING INSIGHTS

42 | Design K-12 school buildings for adaptability and energy efficiency

In this roundtable, engineers discuss the most important trends for K-12 school building design.

Innovative Products. Proven Performance.

If you only think of Greenheck as a fan company, think again. We engineer and manufacture the industry’s most comprehensive line of air movement, control, and conditioning products for commercial, industrial, and institutional buildings. Our energy-efficient products keep occupants comfortable, productive, and safe while supporting sustainability. Let us help with your next project.

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

FRANCES RICHARDS, Associate Editor FRichards@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.

PAUL ERICKSON, LEED AP BD+C Principal, Affiliated Engineers Inc., Madison, Wis.

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.

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

WILLIAM KOSIK, PE, CEM, LEGACY LEED AP BD+C, Associate Principal, Sector Leader, HED, Chicago

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

CALEB MARVIN, PE, Senior Associate, Associate Partner, Certus Consulting Engineers, Dallas

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

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

Fire, life safety considerations for office-to-residential conversion

During conversion from office space to residential units, fire protection engineers have many fire and life safety considerations.

The commercial office building market shifted dramatically during COVID and the trend continues as housing requirements in larger cities take center stage. Cities like Chicago — my hometown — are repurposing vacant central business district offices into residential units, trying to ease the 28% office vacancy rate reported in the city at the end of 2025.

tional expertise in parking structures, mixed-use buildings and compartmentation/passive fire protection.

Adaptive reuse is hardly new and building owners clearly prefer to have full occupancy with paying tenants rather than vacant office space.

Amara Rozgus, Editor-in-Chief

Rezoning, structural issues, energy efficiency, floor plate considerations, housing goals and architectural design all come into play. The risks for owners and developers are high; conversion to residential is costly and can include a lot of red tape.

Looking at the topic from a fire protection engineer’s perspective can make conversion even more daunting. Office towers are frequently designed around open floor plates, while residential buildings feature compartmentalized layouts, higher privacy requirements, varied occupant behavior and a different relationship with the fire and life safety system. While fire protection engineers understand various hazard classifications, the shift in use from office to residential may necessitate addi-

Conversion to residential creates a fundamentally different relationship between occupants and the fire alarm system. These changes directly impact intelligibility, layout-driven notification coverage and system zoning. New partitions, doors, closets and corridor turns reduce speech intelligibility. Even if a voice system was originally installed in the office, it may not provide clear messaging inside new condos unless speakers are redesigned or supplemented. New sleeping rooms within the converted space demand different audible notification contingent on national and local codes and standards.

Ultimately, office-to-residential conversions demand that fire protection engineers treat mass notification systems and emergency communication systems as a redesign challenge, not a reuse problem. Intelligibility degradation, partition-driven device coverage gaps and residential occupant behavior often leave the existing system misaligned with the new risk profile. Targeted upgrades and a documented emergency communication plan are usually necessary. cse

BUILDING SOLUTIONS

John Yoon, PE, LEED AP, McGuire Engineers Inc., Chicago

Alarm fatigue and life safety: improving fire notification

A fire alarm that technically meets code but fails to prompt immediate action can be the difference between a close call and a catastrophe. Here’s why that distinction matters more than you think.

As engineers, we often focus on prescriptive code requirements when specifying and designing fire alarm systems. However, having a functional and effective fire alarm system directly impacts life safety for the occupants of a building. Because of the life and death stakes involved, having a deeper understanding of the underlying code intent and how building occupants will respond to our design choices is critical.

For example, put yourself in the place of a building occupant during an active alarm condition. The following questions illustrate how occupant perception can alter the effectiveness of a code-compliant design:

• When a fire alarm is activated, what is your first reaction?

• Can you immediately identify/understand that it is a fire alarm?

• Is your first reaction to perform an assessment of your surroundings to determine if it is valid alarm? What information is required to make that assessment?

• If you cannot immediately determine what the source of the danger is, what thoughts go through your head? Is there a chance that you might think that it is a false alarm?

• Does your assessment depend on your location and familiarity with your surroundings?

• Is there a delay in your response? What other factors could cause a delayed response?

• If it is a real alarm, what is the response? Fight, flight or something else?

• If flight is the response, do you know if you can and how to escape the building?

• If your answers to any of these are incorrect, what are the consequences?

Fire statistics and human nature

Fire alarms save lives by detecting fires and quickly notifying the building’s occupants, giving them critical time to evacuate safely. Any delay in evacuation could cause serious injury or death.

Even with a high level of risk to life and safety, many people discount the hazards associated with building fires. The National Fire Incident Reporting System (NFIRS) provides some insight regarding the frequency and results of fires. NFRIS is a voluntary incident reporting system used by fire departments nationwide and has been the federal government’s primary tool for collecting fire incident data since its establishment in 1975. While this system is in the process of being replaced, it is still a treasure trove of information.

Per the NFIRS data, deaths are disproportionately higher in residential fires compared to nonresidential fires, even after accounting for incident counts. In the 2024 data, there were 351,000 residential structure fires versus 119,500 nonresidential structure fires reported to NFIRS (roughly 3:1 ratio). A total of 2,890 residential and 130 nonresidential deaths were reported (22.2:1 ratio). For the same reporting period, 10,400 residential and 1,200

‘While lack of an automatic emergency sprinkler system is a significant driver, another surprising reason is “alarm fatigue."’

nonresidential injuries resulting from those fires were reported as well (8.7:1 ratio).

When presented with this information, the fundamental question is: Why are the relative number of deaths and injuries so much higher in residential fires compared to nonresidential building fires? The primary reason is that the residential occupants had an insufficient amount of time to escape. But why?

While lack of an automatic emergency sprinkler system is a significant driver (9.57:1 difference in death rate), another surprising reason is “alarm fatigue.” Human nature in response to frequent false alarms is to become complacent and take alarms less seriously. If the danger (smoke, flames, etc.) cannot be immediately identified, occupants may delay their response or ignore an alarm altogether. In some cases, they may even attempt to silence or disconnect the alarm system.

This apathy can be deadly when a real fire occurs. This can add critical, life-threatening minutes to the evacuation process. To illustrate this point, NFPA 101: Life Safety Code defines three levels of evacuation capability: prompt, slow and impractical.

• “Prompt” is typically 3 minutes or less for small single-story buildings.

• “Slow”’ is longer than 3 minutes.

• “Impractical” is longer than 13 minutes.

The “impractical” classification is usually caused by conditions where occupants are unable to reliably move to a point of safety in a timely manner and/or otherwise incapable of self-preservation. This could include the presence of patients with limited mobility such as in a hospital, prisons/correctional facilities, rehabilitation centers, nursing

homes, etc. In addition to increased staff assistance requirements, these conditions necessitate more stringent fire safety provisions in the construction of that building. In general, delays in recognition and response can push an otherwise “prompt” egress scenario into “slow” or even “impractical.”

Per NFIRS data, the ratio of real alarms to false alarms is 1:2. NFIRS doesn’t use exactly same criteria as NFPA when classifying false alarms. NFPA 72: National Fire Alarm and Signaling Code defines an “unwanted alarm” as “any alarm that occurs that is not the result of a potentially hazardous condition.”

NFPA further subcategorized this into malicious, nuisance, unintentional or unknown alarms. The vast majority of nuisance alarms are not included in the NFIRS data set. Only those that result in a mobilization response from the fire department are included.

For example, NFIRS does not include information on incidents (such as you burning your dinner) that were not reported to the local fire department. If this expanded NPFA criteria could be applied to the NFIRS data, the quantity of false alarms would skyrocket.

According to a 2004 NFPA study, actual fires caused only 2.8% of residential fire alarm activations. Unfortunately, response to alarms is a learned behavior. Frequent false or nuisance alarms train occupants to ignore signals even when the danger is real. Fire alarms are only effective at their intended function if people know how to respond quickly and appropriately, regardless of the setting.

FIGURE 2: Backside of a fire alarm speaker showing a small 24/70 volt transformer and various wattage tap terminals to allow changes in sound levels. Excessive sound levels can impact voice intelligibility. Courtesy: McGuire Engineers Inc.

• Understand fire alarm notification’s role in occupant life safety.

• Review challenges in specifying occupant notification.

• Recognize the relative pros and cons of voice versus temporal alarm tones.

• Examine NFPA 72 and ADA requirements, including ambiguities in sleeping areas, bathrooms and public-use spaces.

• Evaluate recent changes in occupant notification technology.

BUILDING SOLUTIONS

How fast is fast enough for a fire alarm?

NFPA 72 governs how to design and install a fire alarm system, but it does not dictate when it is required within a building. The code that triggers the requirements for fire alarms are typically either the International Building Code (IBC), the International Fire Code or NFPA 101. These codes recognize that the amount of time required to safely escape a building varies by the size, usage and type of people that occupy that building. A fire alarm system is one part of the code’s multipronged approach to help ensure a building evacuation is as safe and as quick as possible.

Once a fire starts within a building, the total time required to egress a building is determined by three factors:

• Fire alarm detection time. This is the amount of time between the start of the fire and when the fire alarm is activated. This functionality is driven by the requirements of NFPA 72.

• Recognition and response time. The occupants must recognize that the alarm is real, assess the level of danger and decide what to do (fight, flight or ignore).

• Egress time. The amount of time required to walk, run or be carried out of the building. This is affected by the length and configuration of the egress path. This is dictated by the IBC, NFPA 101 or whatever the prevailing building code is within a certain jurisdiction.

Prescriptive code requirements influence the amount of time associated with first and third points. However, the second point is highly variable because human judgment is involved. Fire alarm design can have the most direct influence on this judgment process and how quickly occupants recognize and interpret the signal. If there is excessive delay in deciding to exit a building, the smoke, heat and toxic fumes from a fire could severely compromise the egress path and make it impossible to escape.

Functionality of fire alarm notification versus occupancy type

The IBC classifies buildings primarily on occupancy type (how the building is used) and construction type (the materials used to build it and their associated fire resistance). There are 10 major occupancy groups and numerous special use groups defined within the IBC. Each has specific life safety requirements dictated by the physical building size, quantity/type of occupants, characteristic usage and presence of potential fire hazards.

In many jurisdictions, many low-risk building types are not required to have a fire alarm system. For example, 2024 IBC requires that fire alarm systems in Group B business occupancies be provided only if one of the following conditions exist:

• The combined occupant load is 500 people or greater.

• There are more than 100 people above or below the lowest level of exit discharge.

• The fire area contains an ambulatory care facility.

It is generally assumed that the hazards associated with this specific occupancy type are relatively low and that if the building is constructed to the

‘Certain occupancy types are inherently more difficult to evacuate quickly during an emergency.’

prevailing code, there are minimal obstructions to a quick and safe evacuation. Regardless, some jurisdictions may have local code amendments that supersede this and require that a fire alarm system be installed anyway. Reviewing local code requirements is always advisable.

Certain occupancy types are inherently more difficult to evacuate quickly during an emergency. For example, high rise buildings (building’s taller than 75 feet in height), institutional (hospitals, nursing homes, jails) and assembly (theaters, stadiums) all have significant challenges. In some cases, the physical distance of the egress path to get out the building may be an issue. In other cases, occupants may not be able to effectively preserve themselves due to a limitation in understanding the danger or a physical inability to respond. Examples of these limitations include:

• Inability to quickly understand the danger: Young children, large crowds in an unfamiliar setting or sleeping hotel guests.

• Physical inability to respond: Hospital patients with limited mobility or prisoners confined within a jail cell.

These types of limitations often justify more informative notification systems, such as voice notification.

Hearing and vision

The Americans With Disabilities Act (ADA) is a civil rights law that mandates equal access to people with disabilities. The primary disabilities that impact fire alarm design are visual and hearing impairments. ADA-compliant fire alarm systems must provide people with disabilities an

equivalent level of safety to nondisabled people in all public and common use areas (e.g., restrooms, lobbies, hallways, open offices and break rooms). This generally requires that both audible (horns or speaker) and visible alarms (strobes) be provided in these areas.

Some local interpretation of ADA may also expand applicable areas to work areas such as private offices. While ADA generally defines where accommodation for people with disabilities must be made, it does not necessarily provide technical guidance on implementation. It instead relies on NFPA 72 as a referenced standard to establish those technical specifications.

The most appropriate notification method varies depending on the occupancy. For audible notification, generic fire alarm horns or bells may not provide sufficiently detailed information about the nature of the emergency. In many cases, occupants may fail to recognize an audible fire alarm signal, mistaking it for something else like a burglar alarm or equipment fault warning. To reduce this potential confusion with other signs, NFPA 72 mandates a specific sound pattern to provide a universally recognizable fire alarm signal.

Since 1996, NFPA 72 has required that Temporal 3 (T3) be provided for all fire alarm systems using horns. The T3 pattern is an international standard for evacuation signals as defined by ANSI/ASA S3.41 — Audible Emergency Evacuation (E2) and Evacuation Signals with Relocation Instructions (ESRI).

FIGURE 5: Close up of a xenon tube in a conventional fire alarm strobe. Xenon strobe can use draw significantly more current than a comparable LED strobe. Courtesy: McGuire Engineers Inc.

csemag.com

Fire alarm insights

uEngineers must look beyond prescriptive code compliance and recognize that a fire alarm directly influences how occupants perceive danger, make decisions and respond under lifesafety conditions.

u A well-designed fire alarm that accounts for human behavior, alarm fatigue, occupancy type and clear notification is critical to minimizing response delays and ensuring occupants can safely and quickly evacuate.

BUILDING SOLUTIONS

T3 is a pulsed audible signal pattern that consists of a repeating sequence of sounds:

• Three short “on” pulses lasting for 0.5 seconds each.

• Two short “off” pauses that separate the “on” pulses by 0.5 seconds.

• One long “off” pause after the third pulse. This pause lasts for 1.5 seconds before the pattern repeats.

The pattern must repeat for the duration of the alarm condition or a minimum of 180 seconds — whichever is longer. Bells or other similar audible appliances that cannot reproduce the T3 pattern are no longer allowed to be used for occupant notification. Depending on the local jurisdiction’s requirements, use of the T3 pattern may sometimes be retroactive if an existing fire alarm system is significantly modified.

There is also a Temporal 4 (T4) pattern, which is intended to inform occupants of a carbon monoxide emergency. While not intended as an evacuation signal, it is somewhat similar to T3. T4 is also a pulsed audible signal pattern that consists of a repeating sequence of sounds:

• Four short “on” pulses lasting for 0.1 seconds each.

• Each pulse is followed by short “off” pauses that separate the “on” pulses by 0.1 seconds.

• One long “off” pause after the fourth pulse. This pause lasts for 5 seconds before the pattern repeats.

Horn versus voice fire alarms

For an audible alarm signal to be effective, the occupants must be able to hear it above the ambient noise in any given area. NFPA 72 requires that an audible fire alarm be at least 15 dBA louder than the ambient sound or 5 dBA above the peak ambient sound (lasting 60+ seconds), whichever is greater. As a point of reference, 55 dBA is a common ambient sound level in an office environment.

The presence of closed doors, certain furnishings and other items may attenuate the fire alarm signal and as such, special consideration should be made regarding audible devices quantities and locations.

The temptation is to make the alarm so unbearably loud that the occupants won’t be able to ignore it. However, an excessively loud alarm can cause other problems, like inducing disorientation and hearing damage. As such, the upper limit per NFPA 72 is 110 dBA measured 10 feet from the device. In occupancies with high ambient sound levels like industrial facilities, this may be inadequate and visual alarms would instead be required.

In sleeping areas (typically hotels), NFPA 72 now requires 520 hertz (hz) low-frequency audible alarms. Low-frequency alarms still need to comply with the T3 tone requirement. With hearing impaired people, particularly older adults with high-frequency hearing loss, 520 hz has been demonstrated to be more effective at waking sleeping occupants. This requirement was introduced in the 2010 edition but was given a delayed effective date of Jan. 1, 2014. The intent behind the delayed implementation was to allow manufacturers time to develop compliant products.

Even though the requirement has been in effect for more than 10 years, most single station smoke alarms available on the market for small residential occupancies still cannot reproduce a 520 hz signal. Reproducing the signal dramatically increases the power draw requirements beyond what most single station smoke alarms are capable of. Even with hardwired 120-volt smoke alarms, the battery backup still the primary power limitation. If the low-frequency alarm is required, fire alarm sounder bases or speakers connected to a central fire alarm panel are typically used.

As illustrated before, occupants may not know what to do when they hear a fire alarm signal. Even standardized T3 and T4 patterns may not be understood. While occupant training could bridge this gap, it is not always feasible to train building occupants on proper procedures, especially in buildings with transient occupancy.

Voice notification can provide clear, actionable verbal instruction to overcome common issues associated with standard audible fire alarm signals. In many occupancy types, such as high-rise building and large assemblies, voice notification is

required by code for this very reason. While prerecorded voice messages are common, most voice fire alarm notification systems also allow a first responder to make live announcements. The ability to customize messages is critical in effectively managing unexpected emergencies in real-time. As opposed to a blaring horn, a calm and authoritative human voice can help reduce panic and confusion in a potentially stressful environment.

There are downsides to voice fire alarm notification. These include higher costs, increased system complexity and difficulties in ensuring that voice messages are intelligible. For example, hard surfaces or certain room shapes/dimensions can cause reverberation or uneven sound distribution that could distort or make it impossible to understand what is being said.

The term “intelligibility” was introduced in the 1999 version of NFPA 72. Section 4-3.1.5 states:

“Emergency voice/alarm communications systems shall be capable of the reproduction of prerecorded, synthesized or live (for example, microphone, telephone handset and radio) messages with voice intelligibility.”

While this intelligibility requirement existed in principle, 1999 NFPA 72 gave inadequate guidance in defining, designing and documenting that the code requirements were met. Nonbinding recommendations were present within the code’s appendix, but not within the actual body of the code. As such, code compliance became a subjective opinion of the authority having jurisdiction (AHJ).

The 2007 edition of NFPA 72 improved the situation by introducing quantitative testing methods, but still, there were barriers to compliance. That code still maintained a “one-size-fits-all” approach and did not acknowledge that different rooms have different acoustic properties where compliance would be difficult, if not impossible. Examples of challenging areas would include loud industrial areas, mechanical rooms, multistory atriums, etc.

Not until the 2010 version of NFPA 72, which introduced the concept of acoustically distinguishable spaces, did intelligibility requirements for emergency voice/alarm communication systems and mass notifications systems recognize real world conditions. This is detailed within Chapter 24, Emergency Communication Systems.

Strobes enhance, not replace, audible alarms

An effective alarm needs to be clear, easily noticeable and informative. Studies of evacuation behavior have found that relying on an audible alarm without sufficient context (i.e., verbal instructions or awareness of an immediate and present danger) is one of the least effective ways to motivate occupants to evacuate a building.

Fire alarm strobes are intended to complement audible notification by also providing a clear, visual warning that quickly grabs your attention. Where deaf people may be present, in noisy environments or where people might be otherwise hearing impaired (i.e., occupants using headphones in an open office), use of visual alarms is critical in minimizing response times. As noted, any delay in evacuating a building during a fire can significantly increase the likelihood of injury or death.

FIGURE 7: This image illustrates the additional junction box depth required to accommodate the fire alarm notification appliance speaker cone, which won’t fit in a typical 2.125-inch deep junction box. Courtesy: McGuire Engineers Inc.

If not properly applied, misapplication of strobes can cause significant issues. Common issues include:

• Excessive quantities or brightness of strobes can cause disorientation.

• If multiple strobes within a given line-ofsight are not flash synchronized, they have the potential to induce seizures in people with photosensitive epilepsy.

• While not code required, strobes that are not synchronized with the T3 audible signals within a given area can also cause confusion.

• Inappropriate strobe locations can draw attention away instead of towards the desired egress path.

• Strobes in sleeping areas that are not bright enough (110 candela for wall-mounted, 177 candela if ceiling-mounted).

BUILDING SOLUTIONS

• Strobe orientation is incorrect, causing light from it to be distributed in the wrong direction (devices rated for wall installation mounted horizontally on the ceiling).

• Strobes are not properly rated for the environment that they are installed in (i.e., outdoors).

NFPA 72 has required strobe synchronization since the 1996 edition. Given how long this requirement has been in place, compliance might seem be relatively straightforward.

However, technical issues still occur. A key issue is that NFPA 72 does not specify a universal synchronization protocol. As such, the strobe synchronization signals sent on the notification appliance circuit (NAC) are proprietary to specific manufacturers and not compatible with one another. To synchronize strobes on the same NAC, they must use the same protocol — often meaning the strobes must also be from the same manufacturer. In practice, this often leads designers to

‘

A key issue is that NFPA 72 does not specify a universal synchronization protocol. As such, the strobe synchronization signals sent on the NAC are proprietary to specific manufacturers and not compatible with one another.

’

standardize on one manufacturer for all synchronized visual appliances within a notification zone.

To mitigate these limitations, some manufacturers offer NAC power supplies that can generate multiple distinct synchronization protocols. This feature provides greater flexibility in system design and specification, reducing interoperability issues and simplifying code compliance.

In some jurisdictions, the AHJ may require strobes in areas that traditionally didn’t need them, such as private offices or restrooms. This trend toward adding more strobes can increase power demand and push the limits of existing circuits.

Fortunately, the fire alarm industry is moving away from xenon strobes and adopting LED strobes as the new industry standard. LED strobes generally have a much lower current draw than comparable xenon strobes. This can allow more devices to share the same circuit and minimize the cost associated with other fire alarm upgrades that might be triggered by using xenon strobes.

LED strobes work the same as xenon strobes as long as they’re listed to UL 1971 and, where synchronization is required, verified for compatibility by the manufacturer.

However, there are still a few considerations to keep in mind when specifying LED strobes. While xenon strobe tubes emit light uniformly in all directions (are omni-directional), LEDs depend on the aligned lens to properly distribute light. Even with these lenses, they are more directional than xenon strobes. Because LEDs are more directional, photometric coverage must be carefully considered during fire alarm design to avoid gaps in coverage cse

John Yoon, PE, LEED AP, leads the electrical design practice at McGuire Engineers. He is a member of the Consulting-Specifying Engineer editorial advisory board.

Introducing Pentair Fairbanks Nijhuis XRW Series Wastewater pumps, powered by revolutionary Xcentric™ Impeller technology. Built without vane leading edges, allowing solids to pass freely while delivering high-efficiency performance for your operation.

Leaving you with fewer clogs, lower operating costs, and reduced energy consumption*.

BUILDING SOLUTIONS

Carson Cook, PE, Jensen Hughes Inc., Westborough, Massachusetts; and Larry D. Rietz, SET, CFPS, Jensen Hughes Inc., Denver

Surviving survivability: A guide to life safety pathway survivability

A focus on fire alarm, smoke control and low-voltage life safety system circuits shows electrical system cables’ pathway survivability requirements.

The most common requirement for pathway survivability is for an emergency voice/alarm communications system, also known as a voice fire alarm system, installed in a building that uses partial evacuation or relocation strategies.

However, NFPA 72: National Fire Alarm and Signaling Code also includes pathway survivability requirements for nonvoice fire alarm systems that use partial evacuation or relocation strategies,

in-building and wide-area mass notification systems, firefighters’ telephone systems and two-way emergency communications systems for rescue assistance (e.g., area of refuge, stairway, elevator landing and occupant evacuation elevator lobby emergency communications systems). Smoke control systems, often controlled by the fire alarm system, will be discussed as a good example of how building codes can influence survivability installation requirements.

Since its original release in 1993, the NFPA 72, formerly the National Fire Alarm Code, has required pathway survivability in some form for fire alarm circuits and other life safety system circuits. Over those years, requirements have changed and many requirements have been added or modified. In that same time, pathway survivability requirements have been added to model building codes like the International Building Code (IBC). What is pathway survivability as it relates to these codes? And how can a designer, engineer, installer and authority having jurisdiction (AHJ) navigate this complex subject?

Since first being included as a term in 1993, NFPA 72 defines pathway survivability as “the ability of any conductor, optical fiber, radio carrier or other means for transmitting system information to remain operational during fire conditions.” It is the ability of a conductor (i.e., wire) or multiconductor cable to withstand elevated temperatures, as would be experienced during a fire and continue to operate as intended.

In the United States, conductors or cables meant to be survivable without any other protection are listed to UL 2196 Fire Test for Circuit Integrity of Fire-Resistive Power, Instrumentation, Control and Data Cables. This standard evaluates the integrity of cables for their ability to maintain circuit integ-

Table 1: Performance criteria

All pathways comply with NFPA 70 applicable requirements (12.2.3, 12.2.3.4 and 12.4)

Fire-resistive survivable wiring methods are installed in accordance with manufacturer's published instructions (12.2.3.4)

Building is fully protected by an automatic sprinkler system in accordance with NFPA 13

Any interconnecting conductors, cables or other physical pathways protected by metal raceways or metal armored cables

One or more of the following:

(1) One-hour fire-rated circuit integrity (CI) or fire-resistive cable

(2) One-hour fire-rated cable system (electrical circuit protective systems)

(3) One-hour fire-rated enclosure or protected area

(4) Performance alternative approved by the AHJ

One or more of the following:

(1) Two-hour fire-rated circuit integrity (CI) or fire-resistive cable

(2) Two-hour fire-rated cable system (electrical circuit protective systems)

(3) Two-hour fire-rated enclosure or protected area

(4) Performance alternative approved by the AHJ

*References from NFPA 72-2025 edition.

rity when subjected to a standard time-temperature test exposure of up to 1,800°F for two hours and an associated water hose stream test. Listed cables and cable assemblies are known as “circuit integrity” cables. This article will focus on these hard-wired pathways, although any pathway (e.g., wireless) must meet the same performance requirements.

Navigating the survivability code requirements

As previously noted, NFPA 72 has long required some form of pathway survivability. The initial survivability requirements from 1993 were rewritten in the 1999 edition and specific levels of pathway survivability were added in the 2010 edition. The 2016 edition added important exceptions based on the rated building construction, while the 2022 edition added a new Level 4 pathway survivability option.

The 2025 edition of NFPA 72 provides a large amount of information on this subject.

Chapter 12 of NFPA 72 contains the performance criteria of the various levels of pathway survivability. These levels of survivability are not hierarchical, where a higher number level is superior to a lower number level, but rather it is simply a list of levels with different performance criteria. All levels of pathway survivability must be installed in compliance with the applicable sections of NFPA 70: National Electrical Code (NEC) Article 728, Fire-Resistive Cable Systems and Article 760, Fire Alarm Systems (see Table 1).

Where fire-resistive wiring methods are used, they must be installed in accordance with the cable manufacturer’s published instructions. Level 1 pathway survivability allows conventional fire alarm rated wire (e.g., fire power-limited plenum

• Define pathway survivability and how it applies to different life safety systems.

• Understand how to determine required pathway survivability levels.

• Discover best practices for life safety system survivability.

BUILDING SOLUTIONS

and riser) to be installed in a fully sprinklered building where those cables are installed in metal raceway (i.e., conduit) or metal armored cables. Level 2 and 3 pathway survivability require twohour fire-rated cables or enclosures and Level 3 adds the requirement of a fully sprinklered building. Level 4 pathway survivability, which was added in the 2022 edition of NFPA 72, requires one-hour fire-rated cables or enclosures.

While Chapter 12 defines the levels of pathway survivability, it does not mandate when such levels must be used. Those mandates are found in Chapter 23 and 24. For nonvoice, tone-based fire alarm systems (e.g., occupant notification using horns, chimes, etc.) that use partial evacuation or relocation strategies, as noted in NFPA 72-2025 section 23.10.2, the pathway survivability requirements of voice-based systems found in Chapter 24 must be provided.

This change in the 2025 edition was made to align nonvoice and voice-based systems that use partial evacuation or relocation strategies. In the 2022 edition and prior, the only requirement for tone-based systems was that they be designed so that attack by fire within one notification zone shall not impair control and operation of notification appliances outside of that zone.

In NFPA 72-2025 section 24.3.14, we find most of the pathway survivability requirements pertaining to distinct types of fire alarm and emergency communications systems. This section requires that we understand three important pieces of information, in descending order:

1. What evacuation sequence will be used in the building — general evacuation or partial evacuation/relocation?

2. What is the fire resistance rating of the building’s major structural components (e.g., walls, floors, beams, columns, etc.)?

3. What pathway classification and wiring topology will be used for the emergency communications system notification appliance circuits, notification appliance control circuits and communication and control circuit pathways?

With this information, the required pathway survivability level can be determined and designed. For systems that do not employ partial evacuation or relocation, also known as general alarm operation, any level of pathway survivability can be used. For systems that employ partial evacuation or relocation, some level of pathway survivability or equivalency, must be used.

A high-rise building is the best example of a building using partial evacuation, where the building code requirement of evacuating the alarm floor, floor above and floor below is the normal evacuation sequence. A second example is a nonhigh-rise hospital or health care facility that often operates on a shelter-in-place or relocation evacuation sequence and thus pathway survivability requirements must be considered, especially within a common floor with multiple compartments or evacuation and refuge zones.

Once it is determined that partial evacuation or relocation will be used, then the fire resistance rating of the building’s major structural components must be determined. This is because the pathway survivability should be commensurate with the fire-rating of the structure. A building that has no fire resistance construction or one-hour fire-rated construction is not required to install two-hour circuit integrity cabling.

‘It is important to note that the two-hour requirement does not apply to all smoke control systems. ’

Rather, NFPA 72 recognizes that there is no benefit in providing increased protection for circuits more than what the building itself is providing. Buildings, including high-rises, that are built with one-hour construction but are provided with twohour exits and other provisions need to be reviewed in more detail to comply with the correct level of survivability, which is usually the most stringent requirement.

Figure 2 demonstrates how the building construction determines the pathway survivability level. Two-hour fire-rated construction requires Level 2 or 3 pathway survivability, whereas onehour fire-rated construction requires Level 4 pathway survivability. If the building has no fire-rated construction (i.e., less than one-hour fire-rated construction), then redundant and fault-tolerant pathways of Class N or X circuits are required to be installed with a Level 1 pathway survivability.

Significantly, both the 2022 and 2025 editions of NFPA 72 allow Class N or X circuits to be installed with a Level 1 pathway survivability in buildings with one-hour (per section 24.3.14.4.4) or two-hour (per section 24.3.14.4.3) fire-rated construction as an approved alternative to providing two-hour circuit integrity cable or two-hour fire-rated enclosures. This represents a significant opportunity for cost savings, but it requires the fire alarm designer or engineer and the vendor to provide compliant circuits and wiring topology in the building in compliance with section 24.3.14.4.6.

While the description above applies to fire alarm systems, NFPA 72 Chapter 24 applies the same requirements to firefighters’ telephone systems (i.e., two-way in-building wired emergency services communications systems), two-way emergency communications systems for rescue assistance and elevator landing two-way emergency communications systems.

Pathway survivability for IBC Section 909

In addition to the survivability requirements previously outlined in NFPA 72, the IBC, specifically Section 909, contains requirements that apply to the design and installation of control wiring associated with certain smoke control systems to ensure that they can operate during a fire. The two-hour protection requirement for stair pressurization fans and ductwork has existed in the IBC dating back to the 2000 edition. In the 2009 edition, language for control and power wiring to comply with the same protection requirements were introduced. The elevator hoistway pressurization system protection requirement has existed in the IBC since the 2003 edition when the pressurization alternative to elevator lobbies was introduced.

It is important to note that the two-hour requirement does not apply to all smoke control systems. For example, atrium smoke exhaust systems are not required to feature rated control wiring.

The 2024 edition of the IBC requires control wiring, in addition to fans, ductwork and power wiring, for stair (i.e., smokeproof enclosure) pressurization systems to be located outside the building, within the exit enclosure or protected by two-hour fire resistance rated construction (section 909.20.6.1). Three permitted exceptions to the base options are to use UL 2196 listed circuit integrity cable with a rating of not less than two hours, to encase the cable with not less than 2 inches of concrete or to use a listed two-hour fire-resistance electrical circuit protective system or listed fire-rated wrap/foil on a conventional cable installed in a conduit.

Insights

Survivability insights

u Survivability for life safety system pathways has evolved through successive editions of NFPA 72 and the International Building Code, which now provide detailed criteria for how circuits must be protected so they remain functional during fire conditions.

u These code provisions clarify when survivability is required and outline how designers can match survivability methods to building construction, evacuation strategies and system topology.

u While many types of electrical system cables (e.g., emergency lighting, emergency generators, elevator power, etc.) could have pathway survivability requirements, this article will focus on fire alarm, smoke control and related low-voltage life safety system circuits.

BUILDING SOLUTIONS

The IBC requires elevator hoistway pressurization “fan systems” to be protected with the same fire-resistance rating required for the associated elevator shaft enclosure (section 909.21.4.1). This section, however, does not contain the specific protection requirements for control wiring as found for stair pressurization systems. Because elevator shaft enclosures must be of twohour rated construction if over three stories (section 713.4), it can reasonably be assumed that the intent is for the same control wiring requirements and exceptions to apply to elevator hoistway pressurization systems as is required for stair pressurization systems. However, the applicable AHJ should be contacted to verify that assertion.

It is also important to note that in addition to the survivability requirements for control wiring, the IBC requires all wiring, regardless of voltage, to be fully enclosed within continuous raceways as defined by NEC section 909.12.2. The ICC Code Commentary provided with the Code clarifies that a raceway, as defined by the National Electric Code, must be used and that manufactured cable systems such as metal-clad (MC) cable are not permitted.

The term “control wiring” is intended to apply to wiring providing command inputs to smoke control fans, dampers or doors from the UL 864: Standard for Control Units and Accessories for Fire Alarm Systems listed control unit, which can either be a fire alarm control unit or a building management system control unit. It would also be applicable to cable between a listed control unit and the required graphic smoke control panel (i.e., firefighter’s smoke control station in NFPA 72), as well as data communications in system architecture with networked control units.

How to comply with the requirements

Whether trying to comply with the pathway survivability requirements in NFPA 72 or the IBC, the challenges of complying with the requirements are similar. Where the requirements exist for two-hour fire-resistance rated protection of circuits, the following methods, as permitted by the applicable code, can be used for wiring inside the building:

• Use fire-resistance rated construction or enclosures.

– Using a listed fire-barrier system such as concrete/masonry or gypsum board construction.

– Encase the cable/raceway in 2 inches of concrete.

• Use UL 2196 fire-resistive cables:

– Install exposed (i.e., “free air”) circuit integrity cable.

– Install circuit integrity cable inside compliant raceways per the cable’s listing.

– Install manufactured cable systems (e.g., mineral insulated or MC cable).

• Use UL 1724 electrical circuit protective materials.

– Install noncircuit integrity cable in raceways with a fire-resistive rated wrap.

• For NFPA 72 required survivability, use Class N or Class X circuits complying with Level 1 pathway survivability in accordance with NFPA 72 section 24.3.14.4.6 as an approved alternative for two-hour protection. With AHJ approval, this option may be approved for smoke control systems.

As previously noted, the IBC requires smoke control wiring to be installed in a continuous raceway. Therefore, listed “free air” cable and manufactured cable systems are not permissible options for control wiring associated with these systems.

‘

The IBC requires smoke control wiring to be installed in a continuous raceway.’

Compliance with code requirements for pathway survivability also requires compliance with the various product listings of the components that are used. It is important to note that with respect to listed fire-resistive cable and electrical circuit protective materials that the UL 2196 listing carries specific requirements with respect to cable supports, enclosures, attachment to structure, raceway materials and even the pulling lubricant that aligns with the installation that underwent that manufacturer’s fire testing. These specific requirements are part of the listing and are detailed in the manufacturers’ published instructions for each type of circuit integrity product that they offer.

When engineers are specifying these systems, it is important to note the following items:

• For circuit integrity cable systems installed in conduit, typically electrical metallic tubing or intermediate metal conduit must be used. Rigid metal conduit is not permitted.

• Each manufacturer’s listing contains specific requirements (i.e., specific manufacturer’s brand names) for the allowable raceway, couplings, fittings and clamps. Products from other manufacturers are not permitted.

• For all fire-resistive rated systems there are specific requirements for support types and spacing. Attachment is typically required to be made to a masonry or concrete wall/floor carrying the same rating as the cable system. Attachment to other rated assemblies should be reviewed and approved by the AHJ.

• If fiber optic cable is required for fire alarm network wiring, alternative performance methods or products may be necessary due to the lack of UL 2196 listed products currently on the market.

Pathway survivability best practices

A typical high-rise building would need to address pathway survivability for fire alarm occupant notification, stair pressurization systems, elevator hoistway pressurization systems (if applicable), as well as life safety systems used for rescue assistance communications systems. Clearly understanding which circuits need pathway survivability becomes important. Fire alarm pathway survivability applies to circuits necessary to initiate activation of notification appliances, which usually applies to the following:

• Control units, amplifiers and power supplies associated with notification appliance circuits serving floors other than where the equipment is located.

5: Typical high-rise riser diagram showing pathway survivability. Courtesy: Jensen Hughes Inc.

BUILDING SOLUTIONS

‘It is impossible to detail all the specific requirements, exceptions and unique situations that may be faced when trying to comply with pathway survivability.’

• Audio and data network connections between fire alarm control units and notification appliance control equipment.

• Audible (e.g., loudspeaker) and visual (e.g., strobe) circuits originating on a floor other than the one they serve.

• Signaling line circuits used for activation of audible or visual circuits from notification appliance booster panels, power supplies or amplifiers.

• Two-way communication circuits for firefighter telephone, emergency and rescue assistance communications systems.

For smoke control systems, the survivability requirements would apply to the following:

• Control units associated with inputs and outputs to stair (or elevator) pressurization systems.

• Connection between firefighter’s graphic smoke control panels and control units.

• Data network connections between fire alarm control units on the same network where one control unit takes inputs that are activating outputs connected to another control unit.

• Signaling line circuits (fire alarm) or control wiring (building automation system) associated with inputs or outputs to stair (or elevator) equipment (e.g., fans, dampers, doors, etc.)

While providing listed circuit integrity cable can offer flexibility in installation, there is an inherent added cost when compared to standard duty cables due to premiums associated with the cabling itself and more stringent installation and support requirements. The use of rated building construction (e.g., rated shafts or stacked rated rooms or closets) can minimize the use of required fire-resistive rated cables and cable systems, while providing compliant pathways for the various systems that require pathway survivability.

Figure 5 shows an example of a high-rise building’s riser diagram where a combination of stacked rated closets and selective use of circuit integrity cable can be used to comply with applicable codes while minimizing the cost of circuit integrity cables.

By using a building’s rated construction (e.g., rated rooms, closets, shafts or enclosures), standard duty cabling and raceways can be installed. For fire alarm occupant notification dedicated to a specific floor or zone, once those circuits enter that dedicated floor or zone (i.e., within their notification zone) pathway survivability no longer applies and standard cable is used.

However, stair/elevator pressurization control circuit survivability requirements apply up to the point where the circuit terminates on the interface relay of the controlled equipment. Due to this requirement, many designers use dedicated signaling line circuits in dedicated raceway for the smoke control equipment.

Surviving survivability

Unfortunately, it is impossible to detail all the specific requirements, exceptions and unique situations that may be faced when trying to comply with pathway survivability. But pathway survivability can be survived by identifying what systems require pathway survivability, what circuits within those systems require pathway survivability, what evacuation sequence will be used, what fire-rated building construction is provided and what circuit wiring and topology will be deployed.

These critical factors need to be established early and documented so that various trades can work together and so the AHJ can understand and approve these installations. The care taken during the design process will ensure these critical life safety systems will operate as intended during the worst of circumstances. cse

Carson Cook, PE is a fire protection engineer at Jensen Hughes with a focus on challenging fire alarm and fire protection systems.

Larry D. Rietz, SET, CFPS is the fire alarm service line leader for Jensen Hughes and works as a designer, instructor, author and industry advocate.

Mike Lawless, PE, FPE, LEED AP, IMEG, St. Louis; and Mike Walsh, PE, LEED AP, IMEG, Cincinnati

Practical applications of AI in engineering design

Use this basic framework for leveraging artificial intelligence to safely support and enhance the engineering design process under human governance and control.

When speaking about artificial intelligence (AI) at conferences, we often ask our audience two questions: “Who is excited about AI?”

Objectives

• Learn best practices for effectively interacting with artificial intelligence (AI) tools.

• Understand the importance of data quality and governance.

• Know how to incorporate AI to support, not replace, engineering judgment.

“Who is nervous about it?” Most hands in the room go up twice. Both responses are warranted.

AI is the latest in a long line of transformative advancements in the engineering industry, which has evolved from hand drafting and blueprints to computer-aided design, to building information modeling (BIM) and to model-based delivery supported by structured data environments. No doubt the board drafter of the 1960s would never have imagined the integrated 3D models we use today. In the same way, it can be difficult to fully

imagine what the future of engineering will look like with AI.

Whether AI has engineering teams excited, worried or both, it is rapidly becoming part of everyday design practice. (In this article, “AI” refers broadly to computational approaches that perform tasks requiring human-like judgment or search — including algorithmic optimization, constraint-based generative systems, machine learning and large language models colloquially known as LLMs.) Used correctly, AI serves not as a replacement for engineers but as a set of tools that can enhance how we analyze, coordinate, communicate and solve problems. It offers the potential to improve speed, consistency and insight — but also raises important questions regarding reliability, data quality and professional responsibility.

The role of human oversight in AI

Like many companies, our engineering consulting firm sees AI as an exciting opportunity to enhance what our engineers already do. We also recognize that while AI can analyze patterns,

retrieve information and generate technical language at remarkable speed, it does not replace the need for licensed professional judgment; the engineer of record remains responsible for all decisions made, regardless of whether AI assisted in the workflow.

To integrate AI safely and effectively, firms should verify the accuracy, validity and source of AI outputs and restrict final design recommendations and decisions to be made by humans. This approach aligns with National Society of Professional Engineers’ Code of Ethics, which emphasizes competence, responsibility and protecting the public’s health, safety and welfare (see Table 1).

In practice, engineering firms should train their staff to:

• Treat AI as a research and decision-support partner, not as an authority.

• Challenge outputs; do not accept them passively. Confirm and verify the source and accuracy of data and information provided.

• Use AI to accelerate iteration, not to finalize conclusions.

The most effective AI deployments augment the engineer’s capability and capacity by improving comprehension, supporting deeper design reasoning and minimizing redesign.

The critical role of data quality

The effectiveness of AI in engineering design is fundamentally tied to the quality, structure and governance of the data it relies on. In many architecture, engineering and construction (AEC) workflows, project information is manually entered into models, submittals, spreadsheets and internal knowledge libraries. Without intentional management, these data sources can become inconsistent or incomplete, which limits the reliability of AI-driven insights. For AI to enhance decision-making rather than introduce risk, firms must focus first on data integrity.

IMEG addresses this through a combination of curated technical standards, structured project

‘Whether AI has engineering teams excited, worried or both, it is rapidly becoming part of everyday design practice.’

BUILDING SOLUTIONS

Table 1: Integration checklist

Oversight element

Verification

Purpose

Confirm AI outputs are technically correct and contextually appropriate

Example practices

Always cross-check AI-generated calculations and narrative text against codes, standards and project criteria

Provenance Understand where the AI’s information came from Favor curated internal knowledge bases over open, unverified web sources

Professional judgment Ensure final decisions are made by qualified humans

AI recommendations should inform — not determine — design direction

metadata and role-based content stewardship. We also developed an internal AI chatbot that provides a controlled natural language interface enabling engineers to search for firm-approved guidance, past project lessons learned, Autodesk Revit model data and discipline-specific best practices. Unlike open-source generative AI tools, our chatbot only returns information from our firm’s verified internal content libraries. These libraries are maintained by our technical discipline leaders, who serve as data librarians responsible for ongoing review and validation.

This data stewardship model ensures:

by AI-powered TestFit, engineers quickly provided multiple viable site layouts for a shingle manufacturer’s proposed new site and rail spur.

• AI-generated recommendations are traceable to authoritative sources.

• Project teams work from a consistent technical baseline.

• Junior engineers receive guidance aligned with firm standards, reducing training variability.

• Senior engineers can validate design reasoning more efficiently.

Our chatbot is integrated into our broader design input/output (I/O) platform, which houses project metadata, model performance metrics and multi-discipline coordination information. It can read live Revit model data, retrieve design criteria and conduct model health checks, enabling engineers to identify documentation gaps and verify system layouts align with project intent. This integration supports:

• Automated model health analysis (e.g., unconnected systems, incorrect families, inconsistent naming).

• Standardized schedule review and completeness checks.

• Cross-discipline coordination review against firm quality analysis/quality control (QC) benchmarks.

• Structured design documentation such as narratives, code compliance notes and calculation summaries.

All this is critical because AI tools amplify whatever data they are given. When that data is structured, validated and traceable, AI becomes a force multiplier that improves design confidence, reduces rework and supports faster interdisciplinary coordination. When data is inconsistent or poorly governed, AI can reinforce ambiguity, potentially increasing the burden on reviewers or creating downstream construction risk.

For this reason, data governance is not an information technology function; it is an engineering quality function. Successful AI adoption in the AEC industry depends on treating digital content, model health and knowledge libraries with the same rigor applied to calculations and sealed drawings.

Practical AI applications across a project life cycle

One of the clearest ways to understand AI’s role in engineering is to examine how it supports decision-making and enhances performance at different phases of a project. The following four examples illustrate how AI-enabled tools can expand design options, minimize extra work, and improve communication — without replacing the engineering judgment that anchors our work.

Capital planning and feasibility: Reducing operating costs through renewable energy modeling

We recently worked with a heavy machinery manufacturer that sought to reduce its annual electrical utility costs by approximately 50%. The facility operated with a variable but energy-intensive load profile and several strategic options were under consideration, including solar photovoltaics, on-site wind and battery energy storage.

The challenge lay not only in evaluating each technology, but in understanding how combinations of these systems would perform under changing production loads, seasonal weather patterns and utility tariff structures.

To support this early planning effort, we used HOMER Energy, which applies AI-assisted optimization to compare hybrid energy system configurations. Our team uploaded:

• The facility’s measured hourly load profile

• Current and projected utility rates

• Available land area and roof area suitable for renewable installations

• Estimated capital and operations and maintenance costs for solar, wind and battery storage

• Performance characteristics based on local climate and wind resource data

HOMER then evaluated hundreds of system configurations — far more than could reasonably be modeled manually — exploring the tradeoffs between generation capacity, storage sizing, self-consumption rates and life cycle cost. From these outputs, we identified the top five most technically and economically viable scenarios, which we reviewed with the client. For each option, the following was provided:

• Projected annual utility cost savings

• Capital investment requirements

• Simple and dynamic payback periods

• Estimated carbon reduction impacts

• A recommended phasing path aligning improvements with financial planning cycles

The outputs were summarized in a graphical comparison showing the relationship between capital cost and projected utility savings over time, enabling the client to select the configuration that best balanced initial investment, operational savings and sustainability goals (see Figure 2).

AI did not choose the answer — it broadened the range of viable solutions and enabled the team and client to review more options more quickly and with higher confidence. The final recommendation was grounded in engineering judgment, reliability considerations, operations input from facility managers and the client’s financial strategy. This allowed the client to proceed with a phased renewable implementation plan that is projected to significantly reduce electrical costs while improving long-term energy resilience.

‘Data governance is not an information technology function; it is an engineering quality function. ’

BUILDING SOLUTIONS

FIGURE 4: A parametric analysis tool allows structural engineers to rapidly analyze and compare variations in bay sizes and column grid spacing, floor thickness and framing types, shear wall or bracing arrangements and material system selection. Courtesy: IMEG

Early design and system layout:

Rapid site planning and scenario comparison

This project supported the early planning of a new shingle manufacturing facility, for which the owner had purchased a parcel of land but had not yet finalized building placement, logistics flow or operational adjacencies. The site required careful consideration of rail access, truck circulation, raw material storage and finished product handling — each influencing operational efficiency and longterm expansion potential.

Using TestFit, we entered:

• Site topography and environmental constraints

• Required building sizes and functional adjacencies

• Production line flow paths and maintenance access requirements

• Rail spur geometry and minimum radius limitations

• Truck access, trailer parking and employee vehicle circulation zones

TestFit generated numerous site layout options that satisfied the geometric and operational con-

straints. Instead of developing one layout at a time, the team was able to compare multiple viable configurations simultaneously. We narrowed the study to a few high-performing layouts, reviewed them collaboratively with the client and then selected one as the basis of design.

From there, we continued detailed refinement with confidence that the final layout had been chosen from a broad and well-validated design space, rather than from a narrow set of manually developed options. This process allowed the project to move into schematic design with a strong, data-supported site concept, reducing the risk of costly revisions later in the process (see Figure 3).

While site layout decisions shape how a facility operates, early structural choices have significant impacts on cost, schedule, foundation requirements and embodied carbon — yet these decisions are often made after architectural planning is largely set. To address this issue, we developed an AI-assisted, in-house parametric analysis tool to shift structural evaluation earlier, when multiple options are still viable and inexpensive to change. The tool allows structural engineers to rapidly analyze and compare variations in bay sizes and column grid spacing, floor thickness and framing types, shear wall or bracing arrangements and material system selection (steel, concrete, hybrid systems).

For each configuration, the tool provides outputs for estimated material quantities, embodied carbon impacts by material type, approximate installed cost ranges and structural depth implications affecting architectural clearances. This empowers the design team and client to discuss trade-offs not in abstract terms, but by comparing quantified impacts.

For example, a layout with slightly wider bay spacing may reduce column count and improve interior flexibility but could increase member size and embodied carbon. Another option may optimize carbon intensity but influence roof elevation or crane selection (see Figure 4).

By presenting these comparisons early, before systems are locked in, teams can align structural selection with project priorities such as cost, sustainability, construction speed or equipment integration. The result is a faster path to structural

alignment across architecture, operations and cost planning, reducing downstream redesign and supporting clearer communication with cost estimators and contractors.

Design documentation and quality review: Improving model consistency and reducing rework with AI-supported QC

Once a project advances into detailed design, the priority shifts from broad option evaluation to accuracy, coordination and documentation quality. Even in well-managed BIM workflows, information can become inconsistent across models, schedules and sheet sets, especially as multiple disciplines contribute and revisions accelerate near milestone deadlines.

One of the most common issues a team encounters is incomplete or uncoordinated equipment schedules, where information differs between the mechanical, electrical and architectural sheets.

For example, an air handling unit selected early in design may have its airflow, power requirements or connection details updated during coordination but not consistently reflected across all views and schedules. If not identified before bid or procurement, these inconsistencies can lead to construction-phase requests for information, redesign effort or even additional field work.

To address this, we integrate our internal AI platform with the design I/O project data environment to support structured, repeatable quality review workflows. This allows our chatbot to cross-reference Revit model metadata, discipline-specific equipment schedules, design criteria documents and internal standard detail and specification libraries. During design reviews, engineers use the bot to scan schedules for missing or mismatched parameters, such as:

• Airflow listed inconsistently across mechanical schedules and equipment tags

• Electrical loads that do not align with panel schedules

• Equipment dimensions that conflict with architectural clearances

• Connection types that differ from specification language

‘During construction administration, timely and consistent field documentation is essential for communicating design intent, identifying issues and maintaining project momentum.’

Rather than replacing the review process, the AI chatbot highlights where attention is needed, allowing engineers to resolve discrepancies earlier and more efficiently. The final review and approval remain the responsibility of the engineer of record, consistent with professional standards and licensure requirements. This approach results in fewer coordination gaps between disciplines, more consistent documentation across sheet sets, reduced time spent on manual data checking and fewer RFIs and change orders in construction.

The value is not in automation for its own sake; it is in reducing rework and improving design certainty, allowing engineers to spend more time on technical problem solving rather than document reconciliation.

Phase: Construction administration: Real-time jobsite observations with AI-assisted field reporting

During construction administration, timely and consistent field documentation is essential for communicating design intent, identifying issues and maintaining project momentum. Traditionally, jobsite observation (JSO) reports have been assembled after returning from the site — requiring engineers to organize photos, transcribe notes and format reports, often outside normal working hours. This delay could slow response time to contractors and increase the risk of miscommunication.

We have adopted InspectMind AI to streamline this workflow by allowing engineers to document as they go during site visits. Using a mobile device or tablet, engineers capture photos, record voice notes and flag observations directly in the field. The platform automatically organizes these inputs and generates a draft report in the firm’s standardized reporting format. This approach provides two key benefits: faster reporting and response time and consistency across reports and teams.

BUILDING SOLUTIONS

‘Engineers are uniquely well-positioned to use AI effectively. Our discipline is built on rigor, verification, iteration and accountability — the very qualities required to adopt AI responsibly.’

Because documentation occurs in real time, JSO reports are often ready to review shortly after leaving the site, rather than days later. This allows rapid communication with contractors and owners, faster follow-up on corrective actions and reduced backlog of unprocessed field notes. By applying a standardized template and language structure, InspectMind AI ensures that:

• Observations are formatted clearly and professionally

• Multiple engineers produce reports with consistent style and terminology

• Owners and contractors receive documentation that is easier to interpret and act upon

Adopting AI in design does not mean changing the core of what engineers do. It simply means reducing the time spent searching, reformatting, rechecking and recreating information, so more energy can be directed toward solving problems, coordinating systems and creating safe, functional, high-performance environments.

The most effective way to begin using AI is often starting with:

• One workflow (e.g., equipment schedule verification)

• One repetitive task (e.g., initial narrative drafting)

• One project phase (e.g., early site layout options)

• One team willing to pilot and share lessons learned

csemag.com

AI insights

uThe article argues that AI is the latest step in a long evolution of engineering practice and, when used responsibly, can enhance analysis, coordination and efficiency without replacing professional judgment.

u It emphasizes that successful AI adoption depends on strong human oversight and high-quality, wellgoverned data so AI serves as a force multiplier that improves design confidence, reduces rework and upholds ethical and safety standards.

The engineer remains responsible for reviewing, editing and approving the report, maintaining alignment with professional responsibility and sealed document requirements. The AI simply reduces the administrative burden and supports clearer, faster communication during construction. The result is field documentation becomes more timely, more consistent and less time-consuming, allowing engineers to stay focused on resolving issues rather than formatting reports.

Start small and build toward scalable value

The examples demonstrate that AI is not a single technology or one-time initiative, it is a gradual evolution of how engineering work is done. The firms that benefit most from AI are not those that attempt to automate the entire workflow at once, but those that identify small, meaningful starting points, learn from them and expand use with intention.

From there, a firm should document what works, refine the process, then scale gradually to other projects and teams. This is the approach IMEG took in 2023 when we began to develop our own internal AI chatbot, which draws from our own data, and was rolled out in 2024. Development is a continual process as we add new functions and applications. Designers on all teams are using it on multiple workflows, repetitive tasks and more.

Engineers are uniquely well-positioned to use AI effectively. Our discipline is built on rigor, verification, iteration and accountability — the very qualities required to adopt AI responsibly. Furthermore, the path forward is not about replacing engineering judgment; it is about creating more room for it. AI gives us the opportunity to spend less time clicking and formatting and more time designing, analyzing, coordinating, mentoring, innovating and leading. cse

Mike Lawless PE, FPE, LEED AP, is Vice President of Innovation at IMEG.

Mike Walsh, PE, LEED AP, is Senior Director of Industrial at IMEG.

Fire & Smoke

Damper Remote Testing Module

A Simple, Cost Effective Method for Periodic Testing of Life Safety Dampers

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.

BUILDING SOLUTIONS

Grant Kightlinger, CLD, IALD, IES; Lauri Tredinnick, CLD, IALD, LC, LEED AP; Seth Ely, IES; Pivotal Lighting Design of Affiliated Engineers Inc.

Make lighting control design smarter with a cognitive walkthrough

Lighting control technology has evolved from analog to digital technology with a focus on smarter, sustainable, human-centered lighting solutions.

The impact of lighting goes far beyond just making the built environment visible. It plays a crucial role in shaping experiences, affecting moods and improving the functionality of the spaces people occupy. Effective lighting boosts safety, productivity and overall well-being. Likewise, lighting control systems play a significant role in user satisfaction with lighting systems and the built environment, more broadly. Developing technologies such as internet of things and artificial intelligence offer new opportunities for smarter, human-centered solutions.

Objectives Learningu

• Recognize how advanced lighting control systems have created usability challenges.

• Evaluate how UI/UX design techniques can be used to develop and improve lighting control systems.

• Perform a cognitive walkthrough to evaluate a lighting control system design.

At the same time, the advanced functionality of lighting control systems with highly nuanced automation and personalization features can make systems less intuitive for users and pose challenges for learning and usability.

For everyone to benefit from modern lighting controls systems, it is critical that designers develop user-friendly lighting control interfaces. Adding deliberate steps to review and refine the lighting control design can help to ensure intuitive lighting control solutions that satisfy end user requirements.

Evolution of lighting control technology

Lighting control technology has evolved rapidly from its modest beginnings in the 19th century. From simple switches and rheostat dials to the touchscreen and voice activated interfaces available,

these changes have dramatically transformed the flexibility, efficiency and customization of building spaces in ways once thought impossible. The transition from analog to digital systems in the late 20th century marked a significant shift in lighting control technology. Digitalization enabled more complex data exchange, enhanced sensor functionality, centralized control and improved wiring efficiency.

Lighting control systems are currently moving toward greater integration, automation and data-driven approaches. These “smart” systems use varied communication networks, software defined features and integration with building management systems to provide highly granular control and increased resilience. Advanced automated functions offer the potential to improve building performance and change how occupants interact with lighting control systems.

With this great possibility comes a risk that designers lose sight of the defining purpose of a lighting control system: to provide occupants control over the lighting system and their environment. Designing a system with advanced control functionality without leaving users behind is a formidable challenge that grows with the proliferation of new capabilities.

Lighting control design

Lighting systems in large multifunctional facilities often require complex lighting controls that accommodate a variety of users with differing goals. In a hospital room, for example, patients, families, nurses, physicians, cleaning staff and maintenance personnel all need some level of control over the lighting. Each user group has distinct priorities, needs and varying levels of familiarity with available functions.

While there is still ample room for innovation, digital lighting control systems offer all the tools the designer needs to meet code requirements while tailoring the user interface to more closely align with the unique needs of the occupants. For example, modern touchscreen and mobile device interfaces can accommodate multilayer menus, custom graphics, location tracking, floor plans, secure user profiles and much more.

The difficulty lies in harnessing those capabilities to provide a system that allows anyone to achieve the lighting condition they need with minimal experience. Put another way, achieving intuitive and energy-efficient lighting control systems is not primarily a technology problem but rather a design and implementation problem.

How can we ensure that lighting control systems remain intuitive for all, while still delivering the advanced functionality required by the application? One approach is to borrow from a field that has long addressed similar challenges: user interface (UI) and user experience (UX) design. UI/UX designers create systems that support complex tasks by offering clear, intuitive choices tailored to the user's needs. UI and UX need to work in harmony to ensure the process of interacting with technology is user-friendly, functional, intuitive and, ideally, even enjoyable.

One UX/UI design technique for evaluating the intuitiveness and learnability of an interface for different user types is called a cognitive walkthrough. The process is used as a means of testing and refining a prototype system design and involves listing all relevant user types (personas) and systematically walking through the main tasks each user would likely need to perform from their perspective, noting any unintuitive or overly complex steps. Designers then revise the system to simplify these interactions and enhance usability.

The process of cognitive walkthroughs can provide a deliberate quality control measure that reviews the alignment between the lighting control system and the lighting design parameters as well as users’ lighting control needs.

Lighting designers and engineers often perform this kind of analysis informally or subconsciously and consideration of the users and tasks within a space is central to the design process. However, for particularly complex systems designed for use by people unfamiliar with system functions, a more deliberate review may be beneficial.

Optimizing lighting control systems and making them more user-friendly can ultimately yield benefits for both the occupants and the facility. Users directly benefit from a more enjoyable, seamless experience while feeling empowered to adjust the lighting to their own needs and preferences without frustration or asking for help. An intuitive lighting control system increases the likelihood that lights will be turned off when not needed or dimmed when full brightness isn’t necessary, saving energy and extending the usable life of fixtures.

Optimizing lighting control interfaces for users

A cognitive walkthrough can be an effective tool to refine complex lighting control applications with the primary goal of simplifying and streamlining the user experience. It is important to note that the cognitive walkthrough is a means of evaluating and streamlining the system and does not represent the entirety of the design process.

Project parameters such as anticipated tasks and user types should be established very early in design — in conversation with design partners and the owner/end user — to ensure that the designer’s understanding of the space is accurate and complete. These parameters should be thoroughly documented in a narrative format, as they will influence the lighting and lighting control designs. As shown in Figure 1, these steps build upon the parameters of the lighting design process and support a user-experience lens, to guide the lighting control design.

‘Optimizing lighting control systems and making them more user-friendly can ultimately yield benefits for both the occupants and the facility.’

BUILDING SOLUTIONS

The steps include:

Courtesy:

List user types: User types must accurately represent all users who require control over lighting to perform tasks within a space; these can be established through research, experience and discussions with space planners and, ideally, end users.

Additionally, designers should understand whether the user type is familiar or unfamiliar with the space. Familiar users spend a significant amount of time in the space or use it repeatedly. It is assumed they have had time to learn how lighting works in the space and where the lighting controls are located. These users may be more interested in personalizing the environment to their specific needs, mood, comfort and preferences throughout the day.

Unfamiliar users are assumed to have no pre-existing knowledge of the lighting “layers” or zones in the space, where the controls are located or whether controls are available to them. As a result, they may be overwhelmed by a system that does not replicate the switches and dimmers they have in their typical home environment. Automatic controls or simple, easy-to-find, easy-to-adjust controls (e.g., on/off, slide dimmers, motion sensors) are often best to accommodate their needs and goals.

List the primary duties and tasks to be performed: Throughout the design, it is necessary for the designer to anticipate the duties and tasks the users need to carry out within the space. Create a list of tasks, sorted by importance and fre-

quency; critical life-safety tasks rank the highest, followed by the most performed tasks. For spaces with different user types, duties and tasks need to be assigned separately to each user category to determine how they might benefit from lighting controls.

Patient rooms, for example, serve a range of users, including patients, nurses, visitors and other staff. Each user's tasks vary, with different types of controls benefiting different users. Nurses require lighting controls to support care and documentation tasks, while patients benefit from controls that make it easier for them to rest and attend to their individual needs.

Determine lighting control zones, select optimal locations and develop a preliminary plan: After determining the tasks for each user type, the designer should identify which lighting fixtures need to be controlled to perform those tasks and create the associated control zones to accommodate them. Fixtures are grouped within these zones, providing a single point of control for multiple lights and the customization of lighting within an area to suit specific preferences or activities.

The lighting controls should be optimized for each user group by identifying which locations in the space are most intuitive and accessible when the space is used as anticipated. Any tasks that do not have distinct lighting requirements should be controlled together.

Returning to the patient room example, most users, aside from staff who regularly visit the room (e.g., unit nurses), would be relatively unfamiliar with the space (see Figure 2). Critical duties and safety would therefore require light switches to be placed near the door where they are immediately accessible and easily found. When thinking about individual user types, patients may benefit from controls near the bed and outside the bathroom, while nurses may benefit from task lighting controls at work zones in the room.

Once the lighting control zones are determined and the control locations are optimized based on users' duties and tasks, a preliminary lighting control plan can be developed. This involves sketching out control locations, zones and functions, such as switches and dimmers. Each control interface is mapped, minimizing the number of buttons, sliders or other interface components. Controls should

CASE STUDY: How to use a cognitive walkthrough to optimize hospital lighting

THOUGHTFULLY DESIGNED, task-oriented lighting controls in hospital rooms can support nurses’ nighttime workflows, reduce stress and balance clinical efficiency with patient comfort through intuitive, user-centered design.

Lighting controls in patient rooms need to accommodate various users. Nursing staff have the most interaction with patients daily and thus would benefit greatly from lighting controls that enhance their ability to perform specific tasks efficiently. By the same token, nursing staff will likely experience the most stress from poor lighting conditions, such as inadequate lighting for performing necessary activities or turning on excessive light that may disrupt patients’ sleep.

Houston Methodist’s Walter Tower is intentionally designed to enhance patient comfort as well as staff well-being and operational efficiency. Carefully designed task lighting and lighting controls enhance nursing staff’s ability to perform their job effectively. The following scenario considers how lighting controls may be optimized for nighttime nursing tasks in a typical patient room at this facility, where lighting is separately controlled at the room entry, nurse sink and patient bed for ambient and exam lighting. In this scenario, client-specific requests and best-practice protocols required that the design automatically include several lighting control elements:

• An on/off override switch to turn on/off all lighting from one location at the door entry.

• Raise/lower control from the door entry and patient headwall for select control zones.

• Control of high light levels (100 foot-candle requirement) at the medication zone, separate from the work area, which can be adapted to user preferences in daytime/ nighttime settings.

• Patient pillow speaker controls (see Figure 3; omitted on floor plan for simplicity).

Nursing activities can include a variety of tasks, such as checking vital signs, responding promptly to patient calls, assisting with daily living activities and monitoring the patient’s condition. At night, typical tasks present even greater challenges:

• General midnight patient checks.

• Medication administration requiring adequate illumination to check labels, documentation and patient wrist bands.

• Handwashing.

3: Fixtures in a typical patient room at Houston Methodist are grouped within control zones based on anticipated user needs. Courtesy: Affiliated Engineers Inc.

• Visually checking and readjusting the controls of various support machines.

• Responding to an emergency code blue, where all lighting is turned on at full brightness as quickly as possible.

Understanding the lighting control needs of nurses during this timeframe requires that the designer draw on their own health and/or client experiences to put themselves in the nurse’s position and consider how they may function in the space. Once the tasks are identified, the designer can assess how lighting controls can be integrated into the existing space. It can also be very useful to engage with a representative nursing team, to get their experience and wish list, to better inform the design.

A cognitive walkthrough would then be employed to further analyze the nursing staff’s lighting control needs, along with potential pain points and inefficiencies. Table 1 lists questions that may be addressed based on the nursing staff’s typical tasks and potential ways to optimize lighting controls.

Enhancing usability of lighting controls

As lighting control technology continues to evolve, designers must prioritize intuitive controls that cater to diverse user needs. By keeping the unique needs of each user group top of mind throughout the design process, we can develop solutions that enhance usability without sacrificing functionality.

Ultimately, the goal is to ensure that lighting control systems empower occupants, promoting comfort, well-being and productivity in our built environments. As we move forward, collaboration among designers, manufacturers and end users will be key to achieving lighting solutions that are not just smart but genuinely enriching.

BUILDING SOLUTIONS

Table 1: Cognitive walkthrough of a nursing task

Walkthrough subtask Yes/no

Upon entering the room, does the nurse recognize that the lighting needs to be adjusted?

Does the nurse know that they have the ability/access to control the lighting?

Does the nurse know where to access the lighting control, either at the room entry or at the bedside?

Does the nurse have sufficient illumination to approach the bedside to continue the task?

Can the nurse see the control location from the room entry?

Is there a button/interface element that provides sufficient illumination for the task without undue disruption to the patient?

Can the nurse easily reach the control from their position at the bedside?

Can the nurse easily identify which but-ton/interface element needs to be interact-ed with to achieve the desired lighting con-dition?

When the control is activated, is there in-stant visual feedback for the nurse to rec-ognize that the desired lighting condition has been achieved?

When the procedure is completed, does the nurse know that they should revert to the default nighttime lighting condition?

Does the nurse know how to revert to the default conditions?

If the nurse fails to revert the lighting, is there a failsafe that automatically reverts it?

Does the nurse have sufficient illumination to leave the bedside and return to other duties after completing the task?

Yes

Yes

Maybe

Yes

Maybe

Yes

Yes

Maybe

Yes

Maybe

Maybe

Maybe

Yes

Notes

Based on experience, the nurse would know that sufficient lighting is needed and would have difficul-ty completing the task without it.

Based on experience, the nurse would know that they have the authority to control the lighting at night as required to complete the task.

Staff should receive onboarding training to under-stand where lighting controls are located.

Yes, sufficient illumination is provided by night light-ing and spill from patient monitoring equipment.

At night, the nurse may have difficulty seeing the control without additional lighting or due to equip-ment obstructions. Designers should consider ad-justing device locations and finishes or adding indi-cator lighting if there is insufficient illumination to see the control readily.

A raise/lower slider interface for a select zone of fixtures is provided.

Designers coordinated with medical equipment planners to ensure the lighting control position is not obstructed.

Because exam lighting is also controlled from this location, care has been taken to separate the light-ing control devices providing on/off for exam and raise/lower for fixtures expected to be used at night.

The light is directly visible from the nurse's position and the designer has avoided long fade times for lighting adjustments.

Training is required to ensure that lighting is turned off at night when not needed.

Control system training is required. A button/interface element associated with this action is provided.

A conversation with hospital staff is needed to de-termine whether auto-off override is desired.

Sufficient illumination is provided by night lighting and spill light from patient monitoring equipment.

TABLE 1: Cognitive walkthrough of a nursing task.

Courtesy: Affiliated Engineers Inc.

still enable the required functionality while remaining intuitive for unfamiliar users.

To the extent possible, interface components should be arranged from top to bottom, from large to small and from left to right, in order of importance and frequency. Labels must be as universally comprehensible as possible, using color and/or icons to increase understandability. Now that a prototype control design has been established, it can be further refined via the cognitive walkthrough.

Perform a cognitive walkthrough and refine the design: To ensure a user can control the lighting in a way that supports their tasks and its location within the room, a careful walkthrough of the task steps and user movements needs to be performed. Consideration must be given to every part of the task, minimizing assumptions about what the user knows and accounting for users who may have never interacted with a commercial lighting control system.

During the walkthrough, any pain points or inefficiencies in performing the designated tasks must be noted, such as needing to walk across a dark room or get out of bed. Designers should ask:

• Does the user know they can control the lighting?

• Is the user able to see the lighting control device?

• Are lighting controls for the most frequent and important tasks the most visible and easiest to reach?

• Will users intuitively understand how a device controls the lighting? Perhaps the right button is visible, but will users understand the label and know how to engage with it?

• Will users be able to see that something is happening once an action is performed? For example, a very slow fade-on of a light across the room might not provide sufficient visual feedback for the user to immediately notice a change. In this case, they may think their interaction was ineffective and might try something else, potentially interrupting the change they set out to achieve in the first place.

Document and mock-up the design: Once the lighting control design has been thoroughly optimized, the design documentation can be formalized. This includes documenting device locations shown in plan and elevation, planning for device labels and editing the control narrative and control system specifications. Before the finalization of the controls design, the lighting controls can then be further confirmed and tested through a mock-up.

Mock-ups bring the design to life, helping ensure that control system specifications are correct, anticipate potential roadblocks and improve the owner's understanding of the detailed operation of the user interfaces. This is particularly helpful if there are specific user requirements related to graphics visibility or control device functionality, as there is no substitute for a realistic visual representation of the final product.

Finalize documentation: Any feedback resulting from the mock-up and review of the documentation must be incorporated prior to

finalization of the control design documentation for construction. In these later stages of project documentation and even during construction, small shifts and changes may be required due to coordination or field conditions and the original design intent can sometimes be lost. In such cases, revisiting and repeating the cognitive walkthrough as a quality control check can help ensure that all users can still access and manipulate the lighting controls as intended. cse

Grant Kightlinger, CLD, IALD, IES, is a Senior Lighting Designer at Pivotal Lighting Design of Affiliated Engineers Inc., Chicago.

Lauri Tredinnick, CLD, IALD, LC, LEED AP, was Studio Leader at Pivotal Lighting Design of Affiliated Engineers Inc., Chicago.

Seth Ely, IES, is a Senior Lighting Designer at Pivotal Lighting Design of Affiliated Engineers Inc., Seattle.

csemag.com

Lighting control insights

u Advanced technology and lighting design does not ensure userfriendly lighting control interfaces.

u Borrowing from the fields of user interface and user experience design, a deliberate focus on intuitive lighting control system design ensures all users can easily navigate and benefit from modern lighting systems.

25_000529_Plant_Engineering_APR Mod: February 7, 2025 10:20 AM Print: 02/20/25 page 1 v2.5

BUILDING SOLUTIONS

Bryan Bucchianeri, PE; and Macey McEnaney, EIT, CDM Smith, Boston

Understanding ASHRAE 90.1's role in energy codes and regulations

ASHRAE Standard 90.1 is an energy efficiency standard often referenced in the International Energy Conservation Code. Learn to navigate both for building energy standards.

Many different editions of energy efficiency codes, standards and rules have been adopted and adapted by various jurisdictions across the country which requires research and discussion with the authority having jurisdiction during the schematic phase of a building’s design to avoid mistakes and missteps as the design progresses.

International Energy Conservation Code (IECC) and ASHRAE Standard 90.1: Energy Standard for Buildings Except Low-Rise Residential Buildings are two primary documents that provide energy conservation requirements for buildings.

Objectives

• Review the scope and intent of ASHRAE Standard 90.1 and the International Energy Conservation Code.

• Learn how states and municipalities adopt and enforce ASHRAE 90.1 as part of the energy code.

• Understand the different prescriptive and performance paths in ASHRAE 90.1 and the IECC to achieve building energy compliance.

The IECC is an enforceable legal document outlining energy efficiency requirements for design and construction of residential and commercial buildings. The IECC mentions ASHRAE 90.1 as a supplemental requirement that provides jurisdictions with optional requirements to reach “zero energy” buildings.

The IECC is published by the International Code Council, an organization that also creates and updates other international codes such as the International Mechanical Code. ASHRAE 90.1 is an energy efficiency standard, often referenced and incorporated into the IECC, which establishes minimum energy efficiency requirements for design and construction of buildings other than low-rise residential buildings and covers building envelope,

heating ventilating and air conditioning (HVAC) systems, service water heating, power, lighting and other equipment.

ASHRAE 90.1 applies to new buildings and systems, new portions of existing buildings, specifically identified new systems and equipment in an existing site, new systems and equipment in existing buildings or new equipment and building systems that are identified as being part of process applications. The standard also provides methods for determining compliance.

Intent and scope of ASHRAE 90.1

ASHRAE 90.1 is a standard with more detailed and system-specific requirements organized into five sections. Each section provides general requirements as well as the different compliance paths to be followed.

Building envelope: Section 5 of ASHRAE 90.1 provides standards for building envelope. One of the major drivers of this section is the climate zone (detailed in ASHRAE Standard 169: Climatic Data for Building Design Standards), which then impacts many additional sections of the standard such as building envelope, heating and cooling systems and HVAC systems using economizers.

ASHRAE 90.1 breaks down the building component requirements according to climate zone. Building components include the minimum or maximum U and R values and solar heat gain coefficients for various types of roofs, walls, floors, doors and fenestrations. The climate zone should be determined at the start of a design, as that will affect not only the building envelope section but also the other sections described herein.

HVAC systems, equipment and controls: Section 6 of ASHRAE 90.1 covers requirements for

‘ASHRAE 90.1 is an energy efficiency standard, often referenced and incorporated into the International Energy Conservation Code.’

HVAC. The scope of this section is mechanical equipment and systems in new buildings, additions to existing buildings and alterations to HVAC and refrigeration in existing buildings. This section states minimum equipment efficiencies and control guidelines for different types of spaces and equipment including air-source and water=source heat pumps, computer room air conditioning (CRAC) units and other packaged cooling equipment, cooling towers and other heat rejection equipment, gas-fired and oil-fired equipment, commercial refrigerator and freezer systems. This section provides the predominate information on energy efficiency.

Service water heating systems and equipment: Section 7 addresses service water heating systems and equipment in new buildings, additions to existing buildings and alterations to existing service water heating systems and equipment.

Power: Section 8 of ASHRAE 90.1 describes power requirements that apply to all power distribution systems and equipment in new buildings and offers more specific guidelines when dealing with existing equipment and system infrastructure. This section includes an alternate compliance path for CRAC systems that does not need to meet the mandatory provisions that other paths do in which power distribution systems and equipment serving a computer room with information technology (IT) equipment load greater than 10 kilowatts (kW) must instead comply with ASHRAE Standard 90.4: Energy Standard for Data Centers.

Lighting systems, equipment and controls: Section 9 of ASHRAE 90.1 outlines lighting requirements that apply to building lighting equipment and systems, including systems serving the interior spaces of buildings and exterior applications.

IECC as a model code

The IECC is a model code with more broad performance-based requirements. The IECC provides market-driven requirements, which focus more on solving the user’s problems and the needs of the market at the time for the design and construction of commercial buildings and provides the minimum efficiency requirements for them. The IECC provides jurisdictions with the option of supplemental requirements, including ASHRAE 90.1, which provides pathways to achieving the minimum efficiencies required.

In addition, the IECC includes a section for all residential buildings. The IECC is a model building code, meaning it is meant to serve as a model code that municipalities can adopt and amend to account for more specific local conditions.

The IECC references ASHRAE 90.1 as an alternative compliance path, thus allowing some jurisdictions to use the IECC to adopt ASHRAE 90.1 entirely. Section C401.2.2 of the IECC states that commercial buildings should comply with ASHRAE 90.1. ASHRAE 90.1 sets the standard for certain equipment performance requirements while the IECC provides broader overall building performance specifications. In cases where the IECC has stricter requirements, those requirements take precedence.

Most states have adopted a current or past edition of both the IECC and ASHRAE 90.1 as their energy codes. Alabama, Washington, D.C., Indiana,

FIGURE 1: Map of the equivalent energy codes by state. Information courtesy of the Office of Energy Efficiency and Renewable Energy webpage. Courtesy: CDM Smith

BUILDING SOLUTIONS

Minnesota, New Jersey, Oregon and West Virginia adopted ASHRAE 90.1 as their current commercial code.

Following the correct code

Jurisdictions can choose which edition of the IECC and ASHRAE 90.1 to follow; therefore, throughout the United States, different states have adopted different editions of each standard. Oklahoma, for example, still references the 2004 edition of ASHRAE 90.1 and adopts the 2006 edition of the IECC as its base energy code. Many states have incorporated stricter requirements into their adopted energy codes and some states in the northeastern United States, such as Massachusetts, have gone further and created “above-code” appendices, referred to as “stretch codes.”

‘The Energy Cost Budget Method can be used in place of the prescriptive pathway for proposed design compliance.’

Some municipalities and jurisdictions within a state use the “home rule,” which allows the municipality or jurisdiction to have the primary authority to adopt, implement and enforce building energy efficiency codes. These local requirements are stricter than the requirements of the IECC and ASHRAE 90.1. The states that allow their local governments to use the “home rule” include Arizona, Colorado, Kansas, Missouri, North Dakota, South Dakota, Texas and Wyoming.

The codes have evolved substantially during the past 20 years; the requirements in one state can be different from those in another state using newer editions of these codes (see Table 1).

Achieving code compliance

The IECC and ASHRAE 90.1 provide different paths for evaluating compliance. Path determination depends on criteria such as the condition (new or existing) of a building or system and the desired performance goals. The compliance pathways in the IECC are the prescriptive method, the total building performance method or compliance with ASHRAE 90.1.

ASHRAE 90.1 Section 4 details the compliance paths as conformance with sections 5 through 11, Section 12 the “Energy Cost Budget Method” or Appendix G “Performance Rating Method.” Sections 5 through 11 detail specific paths for the different building components.

The Energy Cost Budget Method is a method that can be used in place of the prescriptive pathway for proposed design compliance unless the design does not have a mechanical system. This method compares the estimated annual cost of energy for the proposed building to the cost for a minimally compliant building, given requirements from the prescriptive path. The Performance Rating Method (also referred to as Appendix G in ASHRAE 90.1), uses a performance cost index equation to compare new buildings and additions with a baseline building.

Focusing on Section 6 “HVAC Systems, Equipment and Controls,” there are five different compliance paths offered: the simplified approach, prescriptive path, alternate compliance, energy cost budget and performance rating. There are also overall mandatory provisions that all compliance paths, except for the simplified approach, must follow. All mechanical equipment systems, including systems that qualify for the simplified approach, must still comply with the requirements in Sections 6.1 “General,” 6.7 “Submittals,” and 6.8 “Minimum Equipment Efficiency Tables.” Additionally, all refrigeration equipment and systems must comply with the prescriptive compliance path, while all HVAC systems must comply with one of the compliance paths — prescriptive or otherwise.

Simplified approach (Section 6.3 in ASHRAE 90.1): This approach is an optional path for compliance that can only be followed if all HVAC systems in the building qualify. To qualify, the building must be two stories or less, have a gross floor area less than 25,000 square feet and each HVAC system must comply with all the requirements outlined in Section 6.3.2; the first of these requirements is that the system serves a single zone.

Mandatory provisions (Section 6.4 in ASHRAE 90.1): Section 6.4 covers the mandatory provisions that all the following compliance paths must abide by. This section references the tables in 6.8.1 that provide minimum equipment efficiencies for standard rating and operating conditions. Additionally, this section provides minimum equipment efficiencies for nonstandard operating conditions, verification and labeling requirements and control and diagnostic requirements.

Prescriptive compliance path (Section 6.5 in ASHRAE 90.1): Section 6.5 covers the prescriptive compliance path. This pathway provides details about when different types of equipment are and are not required.

For example, to comply with this section, air or fluid economizers must be provided unless there are individual fan-cooling units with a supply capacity less than the minimums listed in the section’s tables (in which case an economizer is not necessary). This is the most comprehensive and stringent compliance pathway because all the system components must meet the criteria and because the pathway can be followed for nearly all design cases.

Section 6.5 also provides tables listing the efficiency and other equipment requirements by climate zone, as outlined in the building envelope section of this document, as well as any exceptions. The equipment outlined in this section include:

• Economizers — fluid and air, simultaneous heating control — hydronic systems, dehumidification, humidification, preheat coils and ventilation air heating control.

• Air system design and control — fan systems and variable air volume efficiency and control.

• Hydronic system design and control — boilers and chillers.

• Heat-rejection equipment — air-cooled and evaporative condensers, dry coolers, open- and closed-circuit cooling towers and any other heat-rejection equipment used in comfort cooling systems.

• Energy recovery — exhaust air energy recovery, heat recovery for service water heating and space conditioning, dehumidifier energy recovery.

• Exhaust systems — transfer air, kitchen and laboratory exhaust, radiant heating.

• Refrigeration systems — refrigerated display cases, walk-in coolers and freezers connected to remote compressors, condensers or remote condensing units.

Table 1: State energy code adoption (commercial)

State Current energy code (as of September 2025)

Alabama

90.1-2013

Alaska Home rule

Arizona Home rule

Arkansas

IECC and 90.1-2007

California 2022 Building Energy Efficiency Standards

Colorado Home rule

Connecticut 2021 IECC and 90.1-2019

Delaware 2018 IECC and 90.1-2016

District of Columbia 90.1-2013

Florida 2021 IECC and 90.1-2019

Georgia 2015 IECC and 90.1-2013

Hawaii 2018 IECC and 90.1-2016

Idaho 2018 IECC and 90.1-2016

Illinois 2021 IECC and 90.1-2019

Indiana 90.1-2007

Iowa 2012 IECC and 90.1-2010

Kansas Home rule

2012 IECC and 90.1-2010

Louisiana 2021-IECC and 90.1-2019 Maine 2021 IECC and 90.1-2019 Maryland 2021 IECC and 90.1-2019 Massachusetts

and 90.1-2019 Michigan

and 90.1-2019

and 90.1-2016 Nevada

New Hampshire

IECC and 90.1-2016

IECC and 90.1-2016 New Jersey 90.1-2019

New Mexico

IECC and 90.1-2019

New York 2018 IECC and 90.1-2016

North Carolina 2015 IECC and 90.1-2013

North Dakota Home rule Ohio 2021 IECC and 90.1-2019

Oklahoma 2006 IECC and 90.1-2004

Oregon 90.1-2022

Pennsylvania 2018 IECC and 90.1-2016

Rhode Island 2024 IECC and 90.1-2022

South Carolina 2009 IECC and 90.1-2007

South Dakota Home rule

Tennessee 2021 IECC

Texas 2015 IECC and 90.1-2013

Utah 2021-IECC and 90.1-2019

Vermont 2021 IECC and 90.1-2019

Virginia 2021 IECC and 90.1-2019

Washington 2021 Washington State Energy Code

West Virginia 90.1-2013

Wisconsin 2015 IECC and 90.1-2013

Wyoming Home rule

Notes: “Home rule” refers to a state policy that allows individual cities or counties to adopt and enforce their own energy code rather than a statewide code.

TABLE 1: Energy code adoption by state. Information courtesy of the Office of Energy Efficiency and Renewable Energy webpage. Courtesy: CDM Smith

BUILDING SOLUTIONS

Alternative compliance path (Section 6.6 in ASHRAE 90.1): There are two compliance paths under Section 6.6.

• The first is the computer room system path for HVAC systems, which only serves the needs of a computer room with IT equipment and a load greater than 10 kW, wherein ASHRAE Standard 90.4 must be met instead. All other HVAC systems must follow the prescriptive compliance path in Section 6.5.

CASE STUDY:

• The second is the mechanical system performance path, which was newly incorporated in the 2022 edition of 90.1, and applies when HVAC systems in the building meet the criteria in Section L.1.1.1. To comply with L1.1.1, the following criteria must be met:

–The HVAC system type must be included in Table L1.1.1.

Achieving energy compliance in the design of a wastewater treatment plant

WITH THE CONSTRUCTION of a new wastewater treatment facility on Cape Cod, Massachusetts, the project design team successfully met the energy requirements of Massachusetts’s stringent stretch energy codes through a combination of efficient HVAC system strategies, building envelope performance and lighting performance.

In early 2023, CDM Smith began the design of a new wastewater treatment plant located in a town on Cape Cod, Massachusetts. The town had been planning a multiyear wastewater collection, treatment and effluent disposal project that would reduce the nitrogen loading to their waterways and comply with the limit requirements of their groundwater discharge permit (GWDP).

The town submitted a comprehensive wastewater management plan in 2022, which identified the town’s intended 40-year multiphased approach to construct and operate a new collection system and water resource recovery facility. The water resource recovery facility site consists of treatment structures, such as sequencing batch reactor (SBR) tanks, infiltration basins and biological odor control system and multiple buildings, including a headworks facility to provide influent screening, grit removal and sludge thickening; a process building to house equipment required to support the SBRs; and an operations building with maintenance shop, laboratory, control room, locker rooms, offices and other administration support spaces.

The site will ultimately discharge the treated effluent to the groundwater through the infiltration basins on-site and will be regulated by the GWDP.

FIGURE 2: Static-plate energy recovery core installed in the dedicated outdoor air system. Courtesy: CDM Smith

Currently, Massachusetts adopts the 2021 edition of the International Energy Conservation Code (IECC) as its “base” energy code and an additional abovecode appendix to the base code called the stretch code. The stretch code is meant to emphasize energy performance (as opposed to prescriptive requirements) and is designed to result in cost-effective construction that is more energy-efficient than that of the “base” code.

An additional above-code appendix to the stretch code was developed as a result of the Next-Generation Roadmap Act (2021), which moved the authority for the stretch code to the Massachusetts Department of Energy Resources. This code, called the Municipal Opt-In Specialized Energy Code, ensures new construction is consistent with Massachusetts greenhouse gas limits and sublimits, which will be set every five years from 2025 to 2050.

The stretch code is divided into two chapters: 225 CMR 22.00 for low-rise residential buildings and 225 CMR 23.00 for commercial buildings and all other construction.

This Cape Cod town adopts the Massachusetts Stretch Code 225 CMR 23.00, which includes amendments to the 2021 IECC and 2019 edition of ASHRAE Standard 90.1: Energy Standard for Buildings Except Low-Rise Residential Buildings. The stretch energy code has stricter requirements regarding the energy efficiency credits for new buildings.

Where the base code (IECC 2021) requires the new building to achieve a total of 10 credits (based on the relevant Tables in

–The system must serve a building type included in the section but not those system types excluded in L1.1.2.

–The system must also be powered by grid-delivered electricity, natural gas, propane, renewable electricity, renewable thermal energy or distillate fuel oil. To comply, the proposed design’s total system performance ratio (TSPR) of the HVAC system must be greater than or equal to the TSPR of the reference

building divided by the mechanical performance factor.

Energy cost budget (Section 12 in ASHRAE 90.1): This is a performance-based method that cannot be used for building designs without a mechanical system. Compliance by the energy cost budget method requires that the design energy cost be less than or equal to the energy cost budget × (1-(energy credits required/1,000) × an adjustment factor.

Section 4 “Commercial Energy Efficiency” of the 2021 IECC), the stretch energy code requires 15 total credits. Based on a review by the project architect, the headworks facility and process building were classified as low-hazard factory (F-2) use group and the operations building was classified as a mixed use of business (B) and low-hazard storage (S-2).

The engineering team was able to achieve more of the heating ventilating and air conditioning (HVAC) focused credits in the operations building because it included more administration spaces. The basis of design included a dedicated outdoor air system (DOAS) with a static-plate energy recovery core that provided the code-required minimum outdoor air ventilation to the spaces and a variable refrigerant flow (VRF) heat recovery system that provided simultaneous space heating and cooling for occupant comfort. These systems complied with the heating efficiency improvements, cooling efficiency improvements and DOAS credit requirements.

Typically, in the treatment support buildings, such as the headworks facility and process building, most of the HVAC systems are driven by the requirements of NFPA 820: Standard for Fire Protection in Wastewater Treatment and Collection Facilities.

Makeup air is provided to a space to maintain an area classification, declassify a space or for odor control. Comfort heating and cooling are not provided to these spaces; makeup air is tempered during the heating season for freeze protection and ventilative cooling is provided during the cooling season. Based on Tables C406.1(1) through (5) in the 2021 IECC, there is not much outside of the heating efficiency improvement credits that HVAC can contribute to regarding the code’s energy efficiency requirements for new buildings.

Despite the multiple energy code and energy regulation requirements of Massachusetts, the project team was able to achieve energy compliance for each building and, in some cases, provide more energy-efficient HVAC systems.

FIGURE 3: Variable refrigerant flow (VRF) diagram for the VRF heat recovery system. Courtesy: CDM Smith

BUILDING SOLUTIONS

‘Navigating the energy efficiency codes and standards can be a daunting and often confusing part of a design because states can

adopt and reference multiple codes and standards with varying equipment or system requirements and compliance paths.

’

Performance rating method (Appendix G in ASHRAE 90.1): This is a method that allows more flexibility in design. Trade-off are allowed when exceeding compliance in some prescriptive areas can allow for not meeting some requirements in other areas.

Section L2.1.5 provides guidance on how to calculate the total system performance ratio (TSPR), which is the basis of proving compliance with this method. A simulation program is used to calculate both the TSPR p (proposed) and TSPR r (reference) using input for the proposed design and requirements from the appendix. The simulation program must be approved by a code official as well as meet minimum capability requirements outlines in L3.2.1 to be used. Unlike appendix G, this method does not allow tradeoffs.

Navigating ASHRAE 90.1

ASHRAE 90.1 provides requirements and guidelines for the design of various sites and buildings. By following this standard, compliance with the IECC typically can be met, and it is also important to ensure the design meets the jurisdictional requirements.

Both the IECC and ASHRAE 90.1 provide performance-based and prescriptive pathways to ensure compliance with the energy requirements. ASHRAE 90.1 works within the IECC as an alternative compliance path to the IECC.

ASHRAE 90.1 insights

uThe IECC and ASHRAE 90.1 together form the foundation of U.S. building energy regulation, with the IECC serving as an enforceable code and ASHRAE 90.1 providing detailed, system-specific minimum efficiency requirements for most nonresidential buildings.

uBecause jurisdictions adopt different editions and may prioritize ASHRAE 90.1 asanalternativecompliance path, careful alignment with local code adoptions is essential to avoid design errors and rework.

However, this method still has mandatory sections that must be met by all proposed building designs. This method is useful in project-specific applications and allows a “tradeoff” where some requirements do not need to be met if they can be made up in other areas by exceeding other requirements. Credits can be available for selecting more efficient HVAC and service water heating equipment, optimizing a window area and correctly sizing HVAC equipment. Equations and models comparing a general baseline HVAC system, based on standard practice, to the proposed design are used to determine whether different aspects of the building comply.

Mechanical system performance rating (MSPR) method (Appendix L in ASHRAE 90.1): The MSPR is mentioned as an alternative compliance path in section 6.6. To use this method, the building must comply with all of the criteria listed in L1.1.1 and L1.1.1.1. Many types of HVAC systems are excluded from the MSPR, which are detailed in L1.1.1.2.

New editions of the IECC and ASHRAE 90.1 are continually being released, so it is important to keep up to date with new editions. The 2022 edition of ASHRAE 90.1 included a lot of updates such as new compliance path options like the MSPR, part load modeling and energy credits.

Navigating the energy efficiency codes and standards can be a daunting and often confusing part of a design because states can adopt and reference multiple codes and standards with varying equipment or system requirements and compliance paths. In some cases, states even adopt a “home rule” that allows individual cities or counties to adopt and enforce their own energy code rather than a statewide code. For that reason and to avoid changes and rework later, a designer must research and carefully align with the version of the code that is adopted within the jurisdiction. cse

Bryan Bucchianeri, PE, is a mechanical engineer with CDM Smith.

Macey McEnaney, EIT, is a mechanical engineer with CDM Smith.

DRIVE PERFORMANCE

TAKE THE LEAD WITH HV600

Is your drive performance on track with your building automation program? Trust the Yaskawa HV600 variable frequency drive in the clutch to maximize energy savings and occupant comfort.

• Support for PC and mobile device programming

• Safe programming without main power

• Hand Off Auto LCD keypad with tactile buttons and LED status ring

• Built-in building automation protocols

• Emergency Override for occupant safety

• Built-in impendance for harmonic reduction

• Advanced application presets for fans and pumps

• Unmatched Yaskawa reliability

What performance issues do you need in your variable frequency drives? Call Yaskawa at 1-800-927-5292.

Design K-12 school buildings for adaptability and energy efficiency

In this roundtable, engineers discuss the most important trends for K-12 school buildings and how educational design is adapting to meet future needs.

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

Nolan Amos: Efficient and welldesigned buildings that foster connection and strengthen communities are in high demand. Now more than ever, clients require an experienced partner to guide them through the complex environment surrounding their schools. Budgets are stretched thin with skyrocketing labor and construction costs continue to rise, while communities demand increased energy efficiency and higher-performing heating, ventilation and air conditioning (HVAC) systems. As engineers, we must consid-

Objectives

• Understand how indoor air quality, acoustics and thermal comfort strategies support student health and learning outcomes in K-12 facilities.

• Learn how engineers are designing flexible, future-ready systems to support evolving curricula, technical education spaces and changing classroom uses.

• Identify how electrification, resiliency planning and integrated building systems are shaping energy-efficient K-12 school design across diverse climates.

er the human environment and design for flexibility, adaptability and resilience. This means creating multifunctional afterschool spaces, addressing security needs and providing HVAC systems that can be adjusted or expanded as district requirements change.

Grady Henrichs: Flexibility and adaptability of learning spaces have become essential to educational design. These dynamic environments support individual learning cycles, facilitate applied learning across all age groups and better prepare students for diverse career trajectories. We are experiencing rapid growth in the design of career and technical education (CTE) spaces, and not only in the traditional focuses on woodworking, shop classes or welding. Several new CTE fields in areas such as healthcare and robotics are emerging that require heavy infrastructure considerations.

Abdullah Khaliqi: Current K-12 trends center on health, flexibility and sustainability. Schools are prioritizing improved indoor air quality (IAQ) with enhanced ventilation, MERV-11+ filtration and carbon dioxide (CO2)-based demand-controlled ventilation (DCV).

Energy efficiency is advancing through efficient HVAC systems, LED lighting with smart controls and heat recovery. There is also emphasis on flexible learning spaces requiring adaptable power and data infrastructure. Decarbonization goals are influencing electrified designs and integration of renewables. Safety and security integration (such as mass notification, access control and fire/life safety coordination) is a growing focus.

Amber Lang: Current trends in K-12 school projects emphasize flexibility, creativity and stronger system integration. Spatially, districts are investing in maker spaces, outdoor learning environments and flexible classrooms that support collaboration, hands-on learning and multiple teaching styles. These spaces are designed to adapt over time rather than serve a single function. At the same time, there is greater integration between building and technology systems, allowing lighting, HVAC and audio visual (AV) to work together to support comfort, efficiency and evolving educational models.

John Mongelli: We have noticed a strong push toward eliminating on-site fossil fuel equipment and requiring solar photovoltaic (PV) panels, essentially driving designs toward net-zero-energy buildings.

Steven Mrak: Student health and IAQ remain top priorities for Michigan school districts, with a strong emphasis on measuring and controlling air quality, not just meeting ventilation rates. IAQ monitoring for CO2, volatile organic compounds and fine particulate matter of 2.5 micrometers or smaller is increasingly tied into building automation systems (BAS) to help

Participants

Mechanical Engineer CMTA

Golden, Colorado Grady Henrichs,

K-12 Education

Engineering Leader

DLR Group Omaha, Nebraska

manage long heating seasons while balancing energy use. Higher-efficiency filtration and DCV are commonly requested to support healthy learning environments and winter performance.

CSE: What future trends should engineers expect?

Steven Mrak: One trend I’m keeping an eye on is the almost “micromanaging” of IAQ and individual spaces. Artificial intelligence integration into building management systems is coming, if not already implemented in some ways. Beyond measuring IAQ with air quality monitors, room sensors can count the number of occupants within a space and can vary the outside air provided accordingly. Finding this balance point of IAQ and building energy use will always be on the mind of engineers and building operators. As different types of sensors become available and more widely used, the additional data provided can be used to operate our buildings most efficiently.

Nolan Amos: Engineers should expect a continued push toward high-performance building design. Communities and superintendents are looking for ways to reduce operational budgets and net-zero buildings drastically reduce utility costs. In addition to delivering efficiency, high-performance building design must

promote quality learning environments by minimizing background noise, increasing outdoor air and improving daylighting and biophilia elements, to name a few. Engineers are being challenged to develop adaptable solutions that maximize the built environment and are resilient to unforeseen challenges.

Grady Henrichs: Accommodating the flexibility needed in modern schools requires several engineering solutions, with acoustic considerations being at the forefront of many design discussions. While sustainability is still a major conversation on most projects, resiliency is becoming a larger consideration for many owners. We are also experiencing a period where aging school infrastructure is requiring major renovation of engineering systems within existing buildings. Upgrading to LED lighting and mechanical system updates can greatly improve the learning environment while reducing energy consumption.

Abdullah Khaliqi: Engineers should expect continued emphasis on healthy buildings, including touchless controls, advanced filtration and real-time IAQ monitoring tied into building management system platforms. Electrification and low-carbon HVAC systems like heat pumps are growing as districts pursue decarbonization goals. Smart, integrated controls linking lighting, HVAC, security

Principal, Academic Fitzemeyer & Tocci

Associates Inc.

Woburn, Massachusetts

Amber Lang, LEED AP BD+C

Associate Vice President

CannonDesign Chicago

John Mongelli, PE

Senior Associate

Kohler Ronan Engineers

Danbury, Connecticut

Steven Mrak, PE Vice President

Peter Basso Associates Inc. Troy, Michigan

and occupancy data will become more common. Expect more resilient power infrastructure, including electric vehicle (EV) charging, battery storage and microgrid readiness. Plumbing designs will increasingly include high-efficiency fixtures to conserve resources. Flexibility for future learning models (requiring adaptable power, data and acoustical design)

ENGINEERING INSIGHTS

will continue shaping mechanical, electrical and fire protection systems.

Amber Lang: Looking ahead, engineers should expect deeper integration between building systems, including HVAC, AV, lighting and security, with data shared across platforms to improve performance and user experience. Electrification will continue to drive higher power demands through all-electric buildings, EV charging infrastructure and increased receptacle density to support flexible classrooms and evolving technology. These trends will require early coordination, scalable infrastructure and designs that can adapt as educational and technology needs continue to evolve.

John Mongelli: With several states already adopting versions of the International Green Construction Code — and more expected in coming years — energy conservation and decarbonization have become top priorities. Coupled with growing net zero and LEED goals, this has driven a trend toward implementing efficient heat pump technologies and passive energy-saving measures.

CSE: What are engineers doing to ensure such projects (both new and existing structures) meet challenges associated with emerging technologies?

Abdullah Khaliqi: To meet the challenges of emerging technologies, engineers are designing flexible infrastructure with scalable power and HVAC systems. This includes extra conduit capacity, distribution panels with spare capacity and network-ready controls for future integration of smart devices or learning technologies. HVAC systems are specified with open protocol BAS and cloud-connected analytics for performance tracking. Lighting and AV systems are often device agnostic, supporting plug and play upgrades. In existing buildings, engineers use wireless sensors and noninvasive retrofit strategies to minimize disruption. Collaboration with information technology (IT), facilities and instructional technology teams is key to aligning designs with evolving classroom needs and future proofing performance.

Amber Lang: Engineers are planning for emerging technologies by designing K-12 facilities with flexibility, scalability and future readiness in mind. This includes providing oversized conduit pathways, extra receptacles, robust wireless infrastructure and modular systems that can accommodate new devices or upgrades without major renovations. For both new and existing buildings, we carefully coordinate mechanical, electrical and IT systems to support AV, internet of things and smart building technologies. Early integration of cybersecurity, cloud connectivity and interoperability standards ensures systems remain secure, adaptable and efficient.

Nolan Amos: Addressing the challenges of emerging technologies starts with strong communication and a clear understanding of project goals. As engineers, we serve as trusted advisors and are the experts in the room when it comes to making critical design decisions, such as enhancing the architectural envelope, optimizing building orientation or understanding how a new refrigerant could impact equipment maintenance. Many districts are hesitant to move away from traditional systems due to familiarity and apprehension. Through continuous learning and staying current with industry advancements, we can share insights and educate design partners and building owners about the advantages and disadvantages of new systems — ones that are often more cost-effective, energy efficient and easier to maintain.

John Mongelli: Becoming familiar with emerging technologies is important. New HVAC equipment being offered in the United States has often already been implemented in other parts of the world. As an engineer, it is critical to understand how this new technology should be integrated into a design and, more importantly, to consider the availability of trained technicians and replacement parts before specifying any equipment.

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

Grady Henrichs: Our teams are working on over 20 projects for the U.S. Virgin Islands Department of Education. Many of these schools were damaged by Hurricanes Irma and Maria and are rapidly deteriorating from the tropical environment, so resilience and energy efficiency are key components of the school designs. The new schools are designed to be off grid with electricity provided by PV arrays with two hours of battery backup.

Nolan Amos: CMTA has over 200 million square feet of K-12 design experience nationwide. One of our more recent projects is Bard Early College High School, which involved the full renovation and modernization of a worndown elementary school in downtown Washington, D.C. To achieve the project’s net zero energy goals, we worked closely with the architect to determine

the best wall systems. We also optimized the building envelope for cost and energy efficiency through various energy simulations, infiltration rate calculations, R-value assessments (measuring thermal resistance) and constructability and life-cycle cost analyses. To provide a resilient, high-performance HVAC system, the building used a geothermal water-source heat pump. This system significantly reduced energy consumption and boosted IAQ with DCV. Currently, the building is operating at an energy use intensity of 20.

Amber Lang: For Los Angeles Unified School District (LAUSD), we worked on the Sun Valley Bus Yard, a seven-acre transportation facility that supports approximately 200 school buses and includes administrative offices, maintenance garages, fueling stations and staff parking. Our team designed a comprehensive electrification and EV charging solution to support LAUSD’s transition to zero-emission transportation. The project includes EV charging infrastructure

for 175 electric school buses, eight whitefleet vehicles and replacement of six existing Level 3 chargers. In total, the system consists of 61 Level 3 chargers, 114 Level 2 bus chargers and eight Level 2 whitefleet chargers, along with associated infrastructure upgrades and accessibility improvements.

John Mongelli: Kohler Ronan designed the first new net-zero K-4 school in Connecticut, which employs a closed-loop geothermal system connected to local water-to-air heat pumps for space conditioning, along with a centralized dedicated outdoor air system for ventilation. All major equipment was designed to be indoors to maximize available roof area, allowing large-scale solar PV arrays to be integrated and thereby offsetting the building’s total energy use.

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?

ENGINEERING INSIGHTS

Abdullah Khaliqi: We focus on right-sizing systems, using life cycle cost analysis to select efficient, durable equipment that meets performance goals without overdesign. To reduce costs, we standardize components where possible and incorporate prefabricated assemblies for quicker installation. Engineers coordinate early with architects and contractors to simplify layouts and reduce material and labor waste. Compliance with codes like ASHRAE Standard 90.1: Energy Standard for Buildings Except Low-Rise Residential Buildings and International Energy Conservation Code is achieved through energy modeling and value engineering strategies. Features like smart lighting, natural ventilation and demand-based controls help meet both sustainability and user comfort goals while staying within budget. Stakeholder engagement ensures solutions align with educational needs.

Nolan Amos: Reducing costs starts with identifying clear project goals from the beginning. These goals drive design decisions toward a budget, keeping every discipline in check. Working in partnership with the architect and owner helps shift costs and enables informed decisions to better impact the overall project. High-performance buildings require a clear vision and extensive collaboration among the project team.

Grady Henrichs: Energy modeling has become a crucial

decision-making tool, allowing designers to quickly analyze how design decisions affect system life cycle costs. In many cases, we are working to shift the narrative that energy-efficient buildings require increased first costs. In some cases, tax code changes now allow public and nonprofit schools to claim geothermal tax credits through direct pay. This has made geothermal systems more financially accessible, enabling schools to install more energy-efficient buildings at a lower first cost compared to more traditional systems.

Amber Lang: Engineers balance cost, function and aesthetics in K-12 projects by taking a holistic, strategic approach to design. Early coordination between disciplines helps identify opportunities to streamline systems, reduce redundancies and optimize materials without compromising code compliance or quality. We prioritize scalable and flexible infrastructure, energy-efficient lighting and shared mechanical systems that support evolving educational needs and maintain durability and long-term performance. Design strategies focus on features that enhance the learning environment, such as daylighting, acoustics and user-friendly technology.

John Mongelli: Locating mechanical equipment centrally within the building, such as ventilation units, can allow for smaller duct mains to serve the building wings. This helps to reduce costs and accommodate higher ceilings. While many high-performance schools have pursued geothermal systems, consider using water-to-air equipment in lieu of hot- and chilled-water systems when possible. This approach allows for a single-pipe loop throughout the building instead of two, helping keep costs down.

Steven Mrak: One of the best ways to keep costs down while meeting client needs is to work closely with the district’s facility manager to get a solid understanding of their expectation for the performance of mechanical, electrical and plumbing (MEP) 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 MEP solutions that will meet their needs now and in the future. This is often accomplished by making the choice to pay more upfront for a higher quality piece of equipment or feature, which will ultimately pay dividends later with reduced maintenance costs. cse

csemag.com

K-12 school building insights

uK-12 school design increasingly prioritizes health, flexibility and resilience, with enhanced ventilation, air quality monitoring and adaptable systems that support learning.

uElectrification, renewable energy integration and scalable power and data infrastructure are driving schools toward net-zero-ready designs while accommodating future instructional needs.

Sales

Jami

Sales Account Manager

JBrownlee@wtwhmedia.com 224-760-1055

Jack Gillerlain JGillerlain@wtwhmedia.com 773-909-2718

Sales Account Manager Richard Groth RGroth@WTWHMedia.com 774-277-7266

Sales Account Manager Judy Pinsel JPinsel@WTWHMedia.com 847-624-8418

Sales Account Manager Susan Powers SPowers@wtwhmedia.com 847-380-0469

Publication Services

McKenzie Burns, Marketing Manager MBurns@WTWHmedia.com

Courtney New, Program Manager, Content Studio CNew@WTWHMedia.com

Rick Ellis, Director, Audience Growth 303-246-1250, REllis@WTWHMedia.com

Custom reprints, print/electronic: Matt Claney, 216-860-5253, MClaney@WTWHMedia.com

Information: For a Media Kit or Editorial Calendar, go to https://www.csemag.com/advertise-with-us.

Letters to the editor: Please email us your opinions to ARozgus@WTWHMedia.com. Letters should include name, company and contact details, and may be edited.

When a seismic event strikes, every second counts. Electrical infrastructure must not only endure the physical shock but be ready to return to operation as soon as possible.

That’s why seismic certification isn’t just a checkbox, it’s a powerful statement about a product’s resilience and reliability.

Engineered for quality.

Rheem® commercial heating & cooling products are designed by our local engineers with feedback from contractors just like you—and rigorously tested in a variety of applications and harsh climates to deliver the highest quality products. Choose Rheem for powerful performance in a simple package that’s engineered for life™

RheemCommercial.com