Full-Scale Flammability Measures for Electronic Equipment.
Full-Scale Flammability Measures for Electronic
Equipment.
(1780 K)
Bundy, M.; Ohlemiller, T. J.
NIST Technical Note 1461; NIST TN 1461; 52 p. August
2004.
Keywords:
electronic equipment; flammability; fire hazard;
thermoplastics; enclosures; resins; ignition; ignition
source; cone calorimeters
Abstract:
This report describes an experimental investigation by
NIST to study the fire hazard of electronic equipment
having thermoplastic enclosures. This work was part of
the project titled "Flammability Measures for Electronic
Equipment" which was supported under the NIST "Reduced
Risk of Flashover" program. It was one of several
related projects aimed at studying fire growth and
spread on real materials. Consumer electronics are
ubiquitous in today's society. The fact that fires
originating from consumer electronic equipment represent
less than one percent of all residential fires in the
United States is largely credited to the use of flame
retardant plastics. Although fires originating within
these items are rare, the hazard presented when exposed
to a small external ignition source (such as a candle)
is not well known. Even when the equipment is not the
first item involved in a fire its contribution to the
total fire load and impact on flashover of a room can be
significant. Both of these issues are important due to
an increasing number of both candles and electronics in
the home. It should also be noted that in recent years
the number of electronic fires has increased in many
European countries following a reduction in the use of
some flame retardant compounds due to environmental
concerns. It is anticipated that this trend could follow
in the United States. The objective of this work is to
relate the full-scale flammability and fire hazard of
consumer electronics assemblies having enclosures made
from different resin formulations to bench-scale fire
performance of these resins. A research consortium was
established between NIST, UL, Dow, Polyone, Albemarle
and Samsung Cheil to conduct this research. Eighteen
commercial resins were evaluated using three different
standard bench-scale flammability tests. Based on the
bench-scale test results, five of these resins were
molded into 19" computer monitor housings and examined
in full-scale fire tests that measured the overall heat
release rate (HRR) and the heat flux threat to the
surroundings. The selection of these materials was based
on HRR, UL94 performance and physical burning behavior
such as melting and charring. The results are compared
and contrasted to bench-scale results from a previous
study to infer useful guidelines. There is a current
international effort (IEC TC108) to develop a hazard
based standard for electronic equipment. This report
aims to provide useful data to help determine standard
requirements.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899