Beland, Bernard. Copper Behavior Under Fire Conditions. Fire and Arson
Investigator. Vol. 44. No. 4 (June 1994). p 40-43.
Abstract: The typical house may contain several hundred pounds
of copper, either in its pure form in water pipes and electrical wiring,
or in alloys such as brass and bronze. Understanding how copper behaves
under fire conditions may help to resolve questions in the investigation.
This article contains numerous figures which illustrate various damaged
The most obvious reason for the presence of melted copper is that the
fire temperature exceeded the copper's melting temperature. There are many
documented examples of such melting and brazing to solid steel walls. Other
samples of damaged No. 14 copper conductors illustrate typical heat damage
to wire, and are not indicative of an electrical problem. Such samples can
be found at scenes where the electricity is not even connected.
Corroded surfaces, blisters, melting and welding of copper wire over
a significant length is often a consequence of the fire, whereas melting
and welding over a shorter distance of one tenth of an inch most likely
indicates arcing and short circuiting. Such electrical activity is also
a normal result of fire and does not constitute causal evidence.
At one time, it was thought that bead formation on damaged electrical
conductors indicated evidence of arcing. It is now well established that
such behavior is a normal consequence of fire.
If copper comes in contact with molten aluminum, the two will form an
alloy that will result in severe pitting to the copper conductor. Again,
this is a consequence of the fire.
The author performed a number of tests heating copper wires and copper
conductors. His findings indicated that significant corrosion of the wiring
took place due to the plastic electrical insulation which when heated, produced
gases in the pyrolysis process. Heat resistant plastic, which contains many
chemical additives, produced more severe erosion.
Other observations reveal that chemical attack on copper, such as that
which might occur in a refrigerator under fire conditions when refrigerant
gases are released, creates the appearance of corrosion and melting, even
though the copper's melting point had not been reached.
The conclusion of these tests and observations is that fires produce
corrosive chemical compounds. These compounds can significantly corrode
and pit metals, resembling the effects of high temperature and melting,
when those circumstances might not have been present.
For more information, contact:
International Association of Arson Investigators (IAAI)
300 Broadway Suite 100
St. Louis, MO 63102-2808