Furnace type HST 4000


Our offer for the customers is enriched with the “heat soak test”, i.e. soaking of the hardened glass in the temperature of 290° C. This offer is addressed, first and foremost, to the manufacturers of aluminium facades and glass balustrades.

The production process of the flat float glass, being a material for the hardening process, entails the risk of sporadic penetration of slight inclusions of nickel compounds into the glass compound.

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This contamination, remaining in the glass after the hardening process, can, in certain situations, result in the risk of spontaneous cracking of the hardened glass.

This risk is relatively small, however in case of use of the hardened glass in the facades, balustrades or in other places with difficult access, it can be and should be prevented.

The method allowing to avoid the problems with spontaneous cracking of the hardened glass is testing of the glass in the process of the so-called Heat Soke Test.
The control and visualisation of the process takes place with the use of 12 temperature sensors and a computer.
The precise measurement of the air and glass pane temperature allows to select the heating process parameters during the test in an optimal manner.
The furnace meets the requirements of the following standard:  EN 14179 – 1  “ Heat Soak Tested Thermally Toughened Safety Glass “

Dimensions of glass panels subject to HST

  • Height: 2600 mm
  • Length: 4500 mm
  • Thickness: from 4 mm to 19 mm


  • heating time with full charge (4500kg) - 3 h
  • 290˚C temp. maintenance time -  2 h
  • cooling time -  3 h.

Process cycle in a graphic form presented in the drawing.
Chamber for the HST furnace by ITM