IEEE Electrification - December 2021 - 24

enclosed space. Lastly, if this quantity limit cannot be
feasibly enforced, one proposed design strategy is to activate
emergency ventilation when explosive gases are
detected. This needs to be done consistent with NFPA 69,
at a flow rate sufficient to prevent gases from reaching
their LEL. If all else fails, enclosures that could contain a
potentially explosive gas can be designed with deflagration
panels, consistent with NFPA 68, to direct an explosion
in a nonhazardous direction.
Responding to a Li-ion BESS Fire Event
Imagine a firefighter, arriving at a BESS site with smoke
rising from cracks and corners. In this situation they
would start to assess the potential hazards: is anyone in
danger, could the fire spread, what kind of batteries are
involved? Those involved in the design, integration, and
approval of battery installations should be working to
make this risk assessment as easy and simple as possible.
Firefighters should be able to access the information
required to assess risk and should have the training needed
to interpret this information. Safety critical information
might include: what system chemistry is present, what
percentage of the cells in the system have vented, is the
ventilation system working as expected, what voltages are
present in the system, are the batteries getting hotter or
colder and by how much, what actions have been taken by
the automated systems (e.g., fire suppression), or if there
are any hazardous gases present. Much of this information
can be made available through a fire alarm control
panel that would be placed in a safe location away from
the battery. Table 1 shows a summary of available and
upcoming training resources for first responders in the
United States. Similar training is becoming available in
Europe, Japan, and other locales.
An existing course developed by the National Fire Protection
Agency offers guidance on risk assessment in
energy storage fires such as identifying ac and dc electrical
hazards, common failure modes, shutdown, ventilation,
and other emergency response considerations.
Courses under development focus on both firefighters and
first responders who are building officials. All of the programs
emphasize the importance of preincident planning
and working with local first responders to make sure that
they are aware of the installation and know what to do in
case of a fire.
One of the hardest aspects of responding to a battery
fire, primarily in Li-ion batteries, is knowing when it is safe
to release the equipment back to its owner and leave the
scene. The energy stored within a damaged battery has
the potential to reignite, hours or possibly days, after it has
been previously extinguished ( " stranded energy " ). The preincident
planning should take this possibility into account
and plan for a fire watch, as needed. A modular system
may be restored to operation shortly after a fire, if a fire is
confined to a single module or rack, though often with
reduced performance. However, smoke and fire suppression
could necessitate significant cleanup or refurbishment
before a system can be recommissioned. It is
important to understand that many systems are being
designed to handle a battery cell fire gracefully and that
after some cleaning, part replacement, inspections, and
testing, these systems may continue to operate.
TABLE 1. The existing and upcoming national-level training for first responders in the United States.
Lead Organization Target Audience Description
NFPAa
Firefighter
Self-paced online energy storage and solar systems safety training, fire service edition;
3-h module uses engaging videos, animations, simulations, and review exercises to
inform firefighters about basic electrical theory, types of photovoltaic installations,
battery chemistries, and response strategies
NFPAb
IAFFb
IRECb
Southface Energy
Instituteb
New Buildings
Instituteb
Firefighter
Firefighter
Building officials
Building officials
Develop a suite of training tools, including a multiplayer serious gaming platform
with several energy-related incidents at each scene
Develop training programs by testing installed residential energy storage systems to
understand what happens when batteries fail and pose risks to emergency responders
Introduce educational materials and resources on clean energy codes, standards, permitting,
and inspection for those interacting with solar energy and storage systems
Create educational programming and resources that can be tailored to different
markets and jurisdictions
Building officials Develop guides and education modules to streamline the design, permitting, inspections,
and maintenance of solar, storage, and electric-vehicle charging stations for
single- and multifamily homes and offices
aExisting training.
bTraining under development (as of December 2020).
IREC: International Renewable Energy Council.
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IEEE Electrification Magazine / DECEMBER 2021

IEEE Electrification - December 2021

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