copper wires or pipes could not account for the amount of material flowing from the building.
http://www.youtube.com/watch?v=rOq3HYRiG7Y
the problem of the temperature of the metal is still the same, whether you consider it to be iron, aluminum or copper.
The video depicted Aluminium melting, this is understandable considering the entire face of the building was clad in aluminium sheeting.