Citation

Zicherman JB. Fire Mater. 2001; 25(5): 209-213.

Copyright

(Copyright © 2001, John Wiley and Sons)

DOI

unavailable

PMID

unavailable

Abstract

Analysis of a major fire incident at a home furnishings warehouse led to the conclusion that extended exposure of electrical insulating materials composing a lampholder in a fluorescent lamp were the initial items ignited. It was thought that these items, composed of thermoset polymers, were ignition-resistant materials. However, analysis showed that thermally induced degradation caused the material to degrade into an easily ignited, char-like residue. The parent polymer, highly cross-linked urea formaldehyde, had been initially cast into the lampholder configuration to prevent high voltage conditions and arcing. Thermal and elemental analyses as well as the investigation conducted at the fire site, helped to determine that the original polymer had pyrolysed into a residue differing in both chemical composition - reduced hydrogen and oxygen content - and physical characteristics when compared with the parent material. The changes in the chemical and physical properties of the original polymer explain the observed thermal inertia of the residue and its tendency to smolder (as opposed to the 'parent polymer'). They are characterized by (1) an increased accessibility to oxygen, (2) reduced thermal conductivity and (3) increased proportion of carbon.