NFPA Journal - Fall 2022 - 31

jet fuel is burning on an aircraft carrier
loaded with highly explosive military
ordinance, there's no room for uncertainty.
The same goes for the Federal
Aviation Administration (FAA), which
is charged with keeping millions of air
travelers safe at the nearly 20,000 private
and public airports the agency oversees.
For decades, the US Department of
Defense has set its own performance
specification standards for firefighting
foams on its bases, referred to as MILSPEC.
Since 2017, the DoD has spent at
least $28 million on funding research
to identify fluorine-free foams that
can pass MIL-SPEC performance tests,
which includes being able to extinguish
a fuel fire in less than 30 seconds. To
this point, not one of the dozens of new
foams has managed to pass each part
of the rigorous test, and, as a result, no
FAA-regulated airports or military facilities
have yet abandoned AFFF.
But that will soon change. As part
of the National Defense Authorization
Act passed by Congress in late 2019, the
US Navy is required to publish a new
military specification for a fluorine-free
foam by the end of January 2023 and
make a full transition to fluorine-free
firefighting foams by October 2024.
Congress had imposed earlier mandates
on the FAA to transition airports to
fluorine-free foams by October 2021,
but that deadline was missed. The new
MIL-SPEC regulations now being written
will pave the way for both airports
and military bases to make the switch,
which by all accounts will be a massive
undertaking requiring a significant
investment. According to a report to
Congress last October, the military still
has about 3 million gallons of AFFF concentrate
remaining at its facilities, and
it is estimated that civilian airports have
at least three times that.
Although the military has yet to
officially approve a fluorine-free foam
for use at its facilities, there are now a
few dozen products that have passed
performance tests developed by credible
testing and approval authorities, such
as UL. Of the 70 or so fluorine-free foam
products now on the market, about
half have credible approvals/listings,
according to the Research Foundation's
roadmap report.
The NFPA standards that address
foam suppression-including NFPA
11, Standard for Low-, Medium-, and
High-Expansion Foam, and NFPA 30,
Flammable and Combustible Liquids
Code, as well as NFPA's suite of standards
for the protection of airfield
and airport facilities-focus mainly on
hardware and do not stipulate which
type of foam can or should be used.
As such, little has changed so far in
NFPA 11 regarding the transition to
fluorine-free foam, other than adding
information about the new foams in the
Annex, said Back, who is a member of
one-size-fits-all solution that can put
out most fuel fires the same way every
time, the effectiveness of a fluorine-free
foam depends on myriad factors, including
the type of fuel being protected,
the depth and temperature of the fuel,
and more. Those factors inform which
foam concentrate is used, which in
turn dictates the necessary equipment
and discharge devices, Souza said. " It
becomes really specific to the application, "
he said. " You can't do anything
until you answer the question of which
concentrate you'll use, and everything
else flows from that. "
" NEW REGULATIONS NOW BEING WRITTEN WILL PAVE
THE WAY FOR BOTH AIRPORTS AND MILITARY BASES TO
MAKE THE SWITCH TO FLUORINE-FREE FOAMS, WHICH
BY ALL ACCOUNTS WILL BE A MASSIVE UNDERTAKING
REQUIRING A SIGNIFICANT INVESTMENT. "
the technical committee. Since the new
foam concentrates are still undergoing
testing, there hasn't yet been a need
for significant changes to the design or
protection strategies outlined in NFPA 11
for fixed-system foam application.
" The testing data seem to suggest
that you're probably still OK using these
new products in legacy systems in many
applications as long as you go through
the right process of getting it approved
for that application, " Back said. An
important caveat to that, however, is
that the new foams have not yet been
tested by a major real-world event. If a
catastrophic incident did reveal flaws
in how well the new foams perform
within existing system designs, it would
likely result in the technical committee
revisiting the design parameters of those
systems, Back said.
But this does not mean that facilities
can simply replace the existing AFFF
concentrate in their fixed systems with
a fluorine-free foam. In fact, the experiences
of facilities that have made the
switch suggest an array of new challenges
and considerations.
As with fire departments, the first
problem facilities will face is figuring
out which of the new foams will
meet their needs. Whereas AFFF is a
Once the concentrate is selected, the
engineering work is only just beginning.
For one thing, the AFFF in the
jars on Souza's mantle have a viscosity
similar to water. By comparison, some
fluorine-free concentrates are so thick
that you could turn a glass of it upside
down and none would spill out. Others
have a consistency more like ketchup
or Jell-O. " The existing equipment is
not calibrated correctly to handle that, "
Souza said. " I wish we could say to
users, 'here are the new bubbles, put it
in your system and it will work.' But it's
way more complicated than that. "
All of those issues were in play
during a project Souza led recently to
design and install a new fluorine-free
fixed foam system at Nantucket Memorial
Airport in Massachusetts, one of
the first such undertakings at an airport
in the US. The viscosity problem,
coupled with other factors, including
the increased densities and application
rates required for the new foams to
work, were engineering challenges that
weren't cheap to solve. Virtually every
part of the foam system that protected
the airport's fuel storage and transfer
area had to be replaced, a scenario
that's likely indicative of what most
airfield facilities will face.
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NFPA Journal - Fall 2022

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