When plastics were initially used in construction, they
were tested in the Steiner tunnel, in spite of the fact that the
tunnel was not always appropriate. For example, samples that
cannot be retained in place above the tunnel floor or which
melt and continue burning on the tunnel floor (typical behavior
for thermoplastic materials) are still being tested with
this equipment, even though results are often misleading. The
Steiner tunnel test can also produce wrong results for thin
materials,21 particularly when they are tested using “poultry netting” support, which absorbs much of the heat generated by
the test specimen (see examples in Table 6.3.4). Single-layer
membranes or thin laminates consisting of a limited number
of similar or dissimilar layers not intended for adherence to
another surface are often supported on poultry netting placed
on steel rods in the Steiner tunnel. The metal dissipates much
of the heat generated by the burning material, thus decreasing
the flame spread artificially