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Technology update
Halon replacement tested
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The U.S. Air Force Research Laboratory's Materials and Manufacturing
Directorate (ML) has announced that it has successfully tested a
replacement material for Halon 1301, which is used in aircraft such as
the F-16 as a fire suppression solution. "Presently, when an F-16 enters
an area where there could be unfriendly fire, Halon 1301 is injected
into the fuel tanks for one-time use to prevent fuel vapors from being
explosive," said Dr. Juan Vitali, Research Scientist at ML's Airbase and
Environmental Technology Division. CF3I fire suppressant material serves
as an inertant in the F-16's fuel tanks, guarding against possible
explosions in the event the tanks are hit by a projectile. Unlike Halon,
the material is neither harmful to the ozone layer nor does it impact
global warming, according to ML. CF3I was developed by ML's Airbase and
Environmental Technology Division at Tyndall Air Force Base, FL, in
cooperation with the Air Vehicles Directorate and Human Effectiveness
Directorate.
"Although Halons make up only a small percentage of the stratospheric
ozone-depleting substances, they have been responsible for as much as 23%
of the ozone depletion observed in recent years," said Vitali. "This is
because Halons do not break down when released into the lower atmosphere
and, within a year, diffuse into the stratosphere where they become
fragmented by the sun's ultraviolet light and release free halogen atoms
that destroy ozone."
According to Vitali, Halon 1301 has been widely used in aircraft as a
fire suppression material since the 1960s because of its ability to
efficiently extinguish fires. However, because of its harmful effects
on the environment, the material was banned by international agreements
starting in 1994. A suitable replacement had not been identified at the
time, forcing regulators to allow its continued use.
Toxicology researchers within the Human Effectiveness Directorate
evaluated the handling risk of the CF3I material and found it acceptable
for use on the F-16. Additionally, the U.S. Environmental Protection
Agency has identified CF3I as an acceptable alternative to Halon 1301
when used only in normally unoccupied spaces.
Information provided by the U.S. Air Force Materials and Manufacturing
Directorate.
Aerospace Engineering August 2000
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