7.4.4 Direct burning
When combustible materials come in direct contact
there is a physical transfer of heat from the ignition
source to the material which in turn releases vapours
which ignite and propagate the fi re. It is true to say that
direct burning makes use of one or more of the previously
discussed methods of heat transfer; however, it
is appropriate to mention this method as a reasonable
proportion of fi res are started in this way and when