NFPA Journal - Fall 2021 - 33

POWER-PACKED A safety concern for eVTOL aircraft
is their energy-dense batteries, which claim a density
of 325 to 400 watt-hours per kilogram, according to
experts. The batteries in most Tesla cars, by comparison,
deliver about 250 watt-hours per kilogram. 
in partnership with Volocopter in
Singapore.
" Unlike a traditional airport, Skyports'
vertiports are being designed
and equipped to fight and mitigate
against risks from alternative aircraft
fuel systems, like lithium-ion batteries, "
said Whalley. " We are working with
VTOL [manufacturers] to understand
the characteristics of their aircraft and
power systems to develop the necessary
a smoldering EV made by BMW into a
giant tank of water to cool its batteries.
In emails to NFPA Journal, two other
companies currently working on vertiport
design declined to comment on
the fire safety considerations for their
facilities, citing proprietary concerns
and saying that currently " standards
are somewhat unknown. "
The massive amount of electricity
vertiports will need to supply aircraft
" THE RULES APPLICABLE TO UAM
GROUND INFRASTRUCTURE ARE
LITERALLY ALL OVER THE MAP
AND ARE NOT FORWARD-THINKING. "
systems and procedures to either fight
an onboard fire or safely isolate the
vehicle or component at a vertiport. "
What exactly that looks like, though, is
not clear.
In an interview with Urban Air Mobility
News (urbanairmobilitynews.com)
in 2020, Whalley speculated what to
do with a burning eVTOL aircraft. " It's
hotly debated, " he told the website. " You
might have to leave the vehicle to burn
out or put it in a bath or something. "
Firefighters in the Netherlands made
headlines in 2019 when they dropped
also introduces the potential for energy
storage systems (ESS's) to be located at
those facilities. (Learn more about how
NFPA is addressing the ESS hazards
faced by the fire service in our feature
story " Guidance Needed " in this issue.)
Alexander realized that a few years
ago when he was helping Uber plan
to enter the UAM market in Los Angeles.
Scorching heat at the time led to
rolling blackouts from the city's power
grid. " If it's 3, 4 in the afternoon and
you have a brownout, you're going to
have to have something to augment
your electrical provider, which is then
a storage system, " he said. " It's going
to have to be a pretty good size, too. If
you have a rooftop facility, you can't
put it on the ground and run cables
up there because the farther away it is,
the bigger the voltage drop, the bigger
the cables. You have to have it as close
[to the vertiport or vertistop] as possible.
Well, the average fire inspector is
not really keen on having an electrical
storage supply system on his roof, especially
on an occupied structure. "
This is also a challenge the UAM
industry recognizes. " Apart from fighting
aircraft fires, vertiports will also
have suppression systems for terminal
facilities as well as on-site, high-wattage
hookups and stationary energy
storage infrastructure, " Whalley said.
" These are primarily based off industry
standards including NFPA 855, Standard
for the Installation of Stationary
Energy Storage Systems. "
'A CODE ABYSS'
According to some experts, the resistance
of authorities having jurisdiction
(AHJs) to vertiports will be enough to
slow the growth of the UAM market.
" It's not like seeking to use a new
building material, " said David Phelan,
who works for South Carolina-based
Davidson Code Concepts, a company
that offers code compliance consulting
NFPA .ORG/JOURNAL * NFPA JOURNAL | 33
VOLOCOPTER
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NFPA Journal - Fall 2021

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