NFPA Journal

A few years ago, I made my first trip to an IKEA store. I quickly figured out that the store wasn’t designed with the American get-in-and-get-out retail model in mind. IKEA hit me with sensory overload and took me on a journey; I found myself following the crowds through the maze-like paths, curious what was around the next corner, losing track of time and the short checklist of items I went in for. What I thought would be a quick trip turned out to be a four-hour excursion.

The longer I was in the store, the more disoriented I became in relation to where I had entered. Even as I wandered in a retail haze, my fire protection engineer mind kept asking, “How am I going to get out of here?” I found myself seeking out the exits in every new section I entered. Although not always blatantly obvious, the travel distances to exits, number of exits, presence of fire doors, and other fundamental fire safety elements appeared to be in place, and code compliant. Even so, I was unsettled by the uncertainty of my direct egress route in the event of a fire. 

SMART & SMARTER: Read about the range of approaches to dynamic exit signage

Historically, static exit sign messaging has served the public well for fire emergencies and for buildings with simple egress layouts. But as complex egress layouts become more common in modern buildings—as in the IKEA I visited—it can be expected that occupants will face greater fire evacuation risks than ever before. That’s why many safety experts are questioning whether the standard static exit signage is enough, considering the growing complexity of building layouts as well as the emergence of other public hazards, such as active shooter events, that require rapid movement of people to locations other than the main entrance.
 
The need for exit signage that captures people’s attention and redirects them in an evolving emergency—not only identifying an exit route but identifying and following the optimal egress path—has driven the development of a new generation of advanced, dynamic exit signage systems. Unlike the static nature of conventional exit signs, a dynamic exit sign is able to leverage technological advancements in sensors, controls, and artificial intelligence algorithms to allow the exit signage system to adapt and display different information based on the real-time conditions in complex buildings. This can present a series of tradeoffs between static and dynamic exit signage, however, which has resulted in debate among regulatory bodies. For dynamic exit signage, the potential benefit is that it can deter occupants from following a direction of travel that may be blocked or otherwise unsafe due to a hazardous condition such as a fire, structural collapse, or an active shooter. Conversely, others worry that more complex egress signage could also create confusion and increase the time required for safe egress.

Although dynamic exit signs are beginning to gain traction, the concept is still poorly defined, with limited academic research, minimal acknowledgement or adoption in codes and regulations, and sparse applications in existing buildings. The construction industry has also pushed back on the use of this technology. Despite barriers, progress continues. The sophisticated implementation of the technology has a long way to go, but many observers believe it is on a promising path.

Exit signage old and new
For nearly a century, exit signage has been a fundamental element of building and life safety through its role of demonstrating clear egress routes in emergencies. For decades, the NFPA and ICC standards have required occupancies with two or more required exits or exit accesses to be provided with illuminated signs that readily identify the location of, and indicate the path of, travel to the exits. Most conventional exit signs include a static light source powered by the building’s electrical system. These signs have no controllable elements, however, as their appearance and illumination are fixed regardless of the situation.
  
The design requirements of conventional exit signs are generally fixed, apart from a few local variances around the world. UL 924, Standard for Safety of Emergency Lighting and Power Equipment, specifies how static exit signs are to be designed and manufactured; requirements set by standards such as NFPA 101®, Life Safety Code®, or the International Building Code (IBC), define the performance of exit signage primarily through placement and visual characteristics. In support of broad awareness and recognition of exits, the type and simplicity of the signage, visual accessibility, architectural features, and other characteristics—including font types and sizes, shapes of pictograms and styles, and the illuminance and colors of the light—are generally standardized and regulated through codes and standards.
  
Code requirements for the type, characteristics, and placement of exit signage typically assume traditional designs, without differentiating between simple and complex buildings. Despite the rapid innovation in architectural design and the increasing complexity of modern buildings, the design of conventional exit signs has remained unchanged for decades and lacks the ability to adapt to changing environments or emerging threats that may arise in complex assembly occupancies. Given the speed of fire development and spread and the rapid evolution of other potential hazards, what may typically be a safe, useable egress route could be blocked or impaired during an emergency. Due to its static nature, however, traditional exit signage can convey a persuasive message regardless of the threat situation down the egress pathway or through the exit door. This has been illustrated in an array of fire incidents, including the Beverly Hills Supper Club (1977), the Scandinavian Star disaster (1990), the Station nightclub fire (2003), the Daegu subway fire (2003), and others.

Additionally, recent research has found that fewer than four in 10 people perceive conventional static exit signs and use them to find their way out of a building under emergency conditions, even when the signs are unobstructed and located directly in their line of sight. Findings like these prompt questions as to whether static exit signage is enough to protect occupants in modern buildings, and in the buildings of the future.

That question underlies much of the work taking place to develop sophisticated alternatives to static exit signage, approaches driven by the rapid advancement of Internet connectivity and artificial intelligence-based technologies. This technological revolution has unlocked opportunities to transform a simplistic, illuminated static exit sign into a dynamic exit signage system that exchanges data in real time to guide occupants to safety.

Unlike conventional static exit signs, dynamic exit signs are not stand-alone devices but are part of an integrated, intelligent system, requiring a control system, sensors, and data communication and processing—and creating such a system presents a number of challenges. Existing sensor data, including information from smoke and heat detectors, must be open to the exit signage system, including the location of sensors in order to characterize the time evolution of smoke density and temperature to characterize the hazard evolution in a space. A centralized data processing system must be established to gather and process information from the networks of sensors, and algorithms must be created to display different light patterns on dynamic exit signs in hundreds of time-varying fire scenarios. The algorithms must then be implemented into the processing and control system to realize the real-time control of the dynamic exit signs. 

Development of such an intelligent system is complex and is largely dependent on the progress of other technologies, such as new sensors, the Internet of Things, computer vision, cloud computing, artificial intelligence, and smart firefighting systems. To help define the current state of dynamic exit signage technology, the Fire Protection Research Foundation recently published a study that included a review of the types of dynamic exit signage systems currently under consideration, ranging from commercially available systems to technology that is still largely theoretical (see “Smart & Smarter,” previous page). While the study underscored the complexity of such systems and the numerous technological gaps that exist in their development, it also suggested the vast promise these systems hold for improving life safety in an array of applications. Decades of continuous research and development will be required to advance the concept of the dynamic exit sign system and its integration with other smart fire, life safety, and building systems. 

Case studies and looking forward
As dynamic exit signage systems have begun to gain traction worldwide, studies have been conducted to demonstrate the effectiveness of these systems. 

For example, a case study conducted in the UK compared occupant response and evacuation efficiency with static signage versus dynamic signage. The dynamic sign utilized an exit sign that under normal operating conditions looks identical to a standard static pictogram emergency exit sign; under emergency conditions, however, the sign became dynamic. Two different dynamic exit signage types were tested. One type was a fixed dynamic exit sign where the fire alarm panel sent signals to the exit signage to provide a dynamic pulsing array of green lights within arrows on the sign to draw attention to the sign and encourage the use of a particular exit. The other type was an adaptive exit sign that had the same characteristics as the fixed exit sign, except that when an exit was no longer encouraged for safe egress, the fire panel communicated with the dynamic exit sign to display a red cross across the sign to dissuade occupants from using that particular exit or egress path. 

These evacuation trials, involving 152 occupants, found that occupants tended to utilize the closest exit in the static signage scenarios, and that the signage itself played a minor role in their decision making. By comparison, dynamic exit signage significantly influenced participant exit route choice by dissuading occupants from utilizing the closer, nonviable exit and encouraging movement toward more distant exits with safer egress paths. In this case, the dynamic exit signage system increased the signage recognition rate by more than 60 percent, facilitated a 50 percent faster evacuation, and improved evacuee decision-making by 44 percent compared to static signage. These are remarkable results, considering that the standard occupant response when only static exit signage is present is to go to the nearest exit or back to the door where they entered, actions that underscore the passive nature of static signage and its relatively weaker influence on changing occupant behavior. The dynamic concept, therefore, appears to address a significant weakness of conventional signage systems by providing a means to adapt the guidance according to the developing hazard environment. However, trials participants indicated that when negative information is conveyed on the sign, it should be coupled with positive exit route information to reinforce the desired action. 

Another case study, conducted in Australia, used dynamic signage in an attempt to increase exit signage visibility, provide audible cues, and offer dissuasive messages to evacuees. The dynamic elements of the signage boosted the sign detection rate by 77 percent and decreased evacuation time by 40 percent.

While such results are promising, gaps remain with respect to standards, technology, and knowledge that are limiting broader public acceptance of dynamic exit signage, as well as its adoption in standards and its broader implementation. Those gaps include a lack of established standards on the positioning of dynamic exit signage, display methods and patterns, and the greatest allowable complexity; underdeveloped technologies that can lead to reluctant public acceptance, tentative adoption of networks and algorithms, and unauthenticated objectives; and insufficient case studies on the actual implementation of dynamic exit signage and its impact on human behavior, the impact of smoke on dynamic signage performance, and more. 

Dynamic exit signage systems are still a new concept in industry and in academia, with the increasingly intelligent systems still primarily in the research and development stages. Given that academic research, codes and standards, and existing building applications are still fairly limited, sophisticated implementation of dynamic exit signage systems still has a long way to go. Based on the early promise shown by this technology, however, researchers and professionals must continue to investigate its impact on human behavior, implement additional real-life experiments, and continue introducing emerging technologies into these systems. Our safety future requires it.

Victoria Hutchison is a research project manager at the Fire Protection Research Foundation. TOP PHOTO: GETTY