Semi-tempered safety glass
The origin of semi-tempered (or heatstrengthended) safety glass can be found in America. The method of production is similar to the production process of tempered safety glass. The serious difference, however, is that the glass sheets are cooled much less abruptly after heating in the incipient deformation area in the air shower. The panes are placed in a voltage range that is between normal flat glass and tempered safety glass, but much more prone to thermally tempered safety glass. It offers advantages especially in applications that have to fulfill special safety criteria.
BGT offers heatstrengthened or semi-tempered safety glass under the name BI-Hestral.