CF3I Stability Under Storage.
CF3I Stability Under Storage.
(421 K)
Donnelly, M. K.; Harris, R. H., Jr.; Yang, J. C.
NIST TN 1452; NIST Technical Note 1452; 40 p. January
2004.
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Order number: PB2004-104192
Keywords:
storage; stability; fire extinguishing agents;
experiments; cylinders; decomposition products; FT-IR
Abstract:
This research investigates the stability of
iodotrifluoromethane (CF3I) during storage. For CF3I to
be used as a fire extinguishing agent, it must be able
to be stored for long periods of time at high pressure
in metal containers without degrading and losing its
effectiveness. For these experiments, CF3I was placed
into cylinders, along with various metal coupons. The
cylinders were stored, some at elevated temperatures in
an oven, for three years and then placed into storage at
ambient temperature for five more years. Infrared
spectroscopy was used to analyze the cylinder contents
during the final five year storage at ambient
temperature by comparing spectra taken before storage to
spectra collected after storage. Analyses of the spectra
showed the CF3I agent volume fraction changed by {+ or
-} 10 % during the five years of storage at ambient
temperature. In addition, for the infrared-active
compounds that could be measured with the spectrometer,
no new peaks developed in the spectra during ambient
storage. Evaluations of the other components showed that
the amount of CO2 present in the cylinders decreased by
63 % or more and the amount of CF3H decreased by 30 % or
more. No new Falkene peaks developed, and changes to
existing Falkene peaks did not significantly affect the
CF3I agent. The combination of both copper and elevated
temperatures caused degradation of CF3I, and the
presence of other metals affected the severity of this
degradation. In particular, the combination of copper
and Nitronic 40 resulted in a complete breakdown of the
CF3I agent during storage at 150 DGC.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899