Citation

Paul M, Issacci F, Catton I, Apostolakis GE. Fire Safety J. 1997; 28(3): 233-252.

Copyright

(Copyright © 1997, Elsevier Publishing)

DOI

unavailable

PMID

unavailable

Abstract

Smoke produced by the pyrolysis of fluorinated wire insulations is characterized to partially provide the data base required to conduct a comprehensive Probabilistic Safely Assessment (PSA) of future human-crewed spacecraft. The smoke is assessed via measurements and observations regarding the size, morphology and elemental composition of the generated particulate matter. Of particular interest is how the microgravity generated aerosols affect the design of future on-board detection and suppression systems. Analyses of the particles generated from short lengths of overheated wires insulated with Tefzel or Teflon (modified forms of ethyltetrafluoroethylene) were performed with the aid of transmission electron microscopy and energy dispersion spectroscopy. Results from short-duration microgravity tests in the NASA Lewis drop tower indicate that the sizes of the primary particles vary depending on the corresponding gravity environment within which they were produced. Tefzel particles produced in microgravity were found to be approximately twice as large as those produced in normal gravity. However, the morphology appears to be gravity independent and material dependent. Cluster formations for both gravity environments are composed of long linear chains of particulate matter. Additionally, a chemical composition analysis for both fluoropolymer insulations suggests that the particulate elemental composition is also independent of the gravity environment.