Technological breakthrough - How a Tunnel Kiln works, Medalta

Italian tile companies struggled to reduce gas
and labor costs. Technological
breakthrough, the rapid single-firing process, in which the hardening process,
material transformation, and glaze-fixing all occurred in one pass through the
kiln. A process that took 225 employees using the double-firing method needed
only 90 employees using single-firing roller kilns. Cycle time dropped from 16
to 20 hours to only 50 to 55 minutes.

Right around the time of World War 2, Medalta upgraded their ceramic firing process, moving from their iconic beehive kilns to a more streamlined approach - the tunnel kiln.