NFPA Journal - Summer 2023 - 55

Smart & Smarter
A range of approaches to dynamic exit signage
TO DEFINE THE CURRENT state of dynamic exit
signage technology, the Fire Protection Research
Foundation initiated a study, " A Review of Dynamic
Directional Exit Signage: Challenges and Perspectives, "
which it published earlier this year (nfpa.
org/dynamic). In partnership with Hong Kong Polytechnic
University, the project reviewed the type
and state of the available dynamic exit signage
technology and connected systems, relevant regulations
and prevalence of use, and the use of dynamic
exit signage in buildings and its impact on
evacuation. It also identified gaps in regulations,
technology, and knowledge that are barriers to further
implementation.
In the report, the authors identified four levels of
dynamic exit signage systems, distinguished by levels
of technological maturity and intelligence:
LEVEL 1: FLASHING LIGHTS
The first level-flashing lights on an exit sign-is the
most basic fixed dynamic exit sign, as it only emits
a flashing light to emphasize a desired action.
To operate, each sign either has independent
hardware activated by nearby sensors or is part of
an exit signage system similarly managed by a central
control panel. The latter system requires all exit
signs to connect to the fire panel, inclusive of heat
and smoke detectors. Upon receipt of an emergency
signal, occupants' attention will be drawn toward
the flashing lights on the exit signs, alerting them to
an emergency. The flashing lights may be integrated
into the exit sign or installed externally on the
surface. Systems of this type are available on the
market and have been incorporated into a number
of assembly occupancies around the world.
LEVEL 2: PERSUASIVE AND DISSUASIVE DESIGN
The second level of dynamic exit signage offers
more directional information, including dynamic arrows,
X's, emergency voices, and additional text.
These dynamic signs respond to a fire detected
by fire or smoke sensors within a building by
displaying persuasive and dissuasive signals. To
achieve this type of dynamic system, the intelligence
level of the system must be capable of evaluating
the fire scene by examining the time and
location of each sensor in conjunction with video
footage from closed-circuit television cameras.
Most fire panels available today can provide
such information, which leads to the need for exit
signage systems with similar intelligence levels to
be connected to an existing fire control panel to
gain access to raw sensor data and alarm information.
The signs can then show a dissuasive signal,
such as a red X, as a way to prevent evacuees from
getting closer to the source of the fire. This type of
system can be deployed at a relatively low cost in
existing buildings, as it leverages existing sensors
and fire panels.
LEVEL 3: DIGITAL TWIN INTEGRATION
This level offers a high level of intelligence and sophistication.
These systems include a digital building
twin-a virtual replica of a physical building
with all of its associated technologies, systems,
equipment, sensors, and actors-that can warn
occupants against entering dangerous areas and
guide them to evacuate through the most efficient
path to safe egress.
This dynamic signage system acts as a subsystem
in the digital twin of a smart building. By
collecting sensor data such as temperature and
smoke visibility from IoT devices in the building,
a digital twin can leverage AI to predict and render
a dynamic fire scene in a building. By recreating
the real-time fire scene and forecasting fire
evolution, the system can compute optimal egress
paths in real time and utilize dynamic exit signs to
indicate them. The 2D or 3D digital model of the
building allows users such as building managers
and the fire department to view depicted fire scenarios
in every room, in addition to observing the
status and flashing pattern of each dynamic exit
sign. While this system presents technological sophistication
that provides a real-time, data-driven
approach to support safer egress, many concerns
and challenges exist relating to system reliability,
liability, and operator skill level, compounded with
the challenges identified for second-level systems.
LEVEL 4: DYNAMIC EXIT SIGNAGE SYSTEMS WITH
ADVANCED HUMAN-COMPUTER INTERACTION
While many of the required technologies for this
type of system are still in the research and development
phase and are not yet mature enough for
market-ready solutions, they are developing rapidly.
These systems are anticipated to build on the
characteristics of third-level systems by visualizing
the position and motion of all occupants in a
building's digital twin based on camera footage
and the use of human behavior models to forecast
the bulk motion of the evacuation flow, including
potential congestion and the evacuation
time of each person. If the system is damaged by
fire, occupants can still receive information about
unsafe areas and optimal evacuation paths via
mobile devices and augmented reality glasses, or
through the use of unmanned aerial vehicles and
robots that can enter the fire scene and assist
with the evacuation process. -V.H.
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NFPA Journal - Summer 2023

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