The temperature controlled section (Tunnel), is subdivided into a number of modules depending from various factors, such as production, loading system, temperatures, thermal process, etc. 
The Tunnel is composed of 3 types of modules: heating only, mix (heating and cooling), cooling only. Each of these is, in turn, composed of an internal case (tunnel) made of high-quality steel suited to the use (usually stainless), high-quality rock-wool insulation, an external frame and panels, painted as desired. The external panels may also be made of stainless steel.



Each module is well equipped of the required air recirculation units, that ensure uniform temperatures, heating units (gas burners or electrical elements), inlet valves to supply fresh air from the outside for cooling purposes and, in the cooling-only areas, hot air outlets. 



The heating power is appropriately distributed in the various areas, to allow for working at all possible temperatures based on the annealing requirements of the various types of glass (from crystal to borosilicate), and may be extended to perform specific treatments, such as pyrolysis.
The temperature is picked up by thermocouples arranged so as to measure the temperature in strategic points for perfect system functioning.
The tunnel exit is always fitted with one or more doors that may be raised by hand or by motor.