Description

Glass is intrinsically brittle and unable to withstand tensile stresses. Yet, through thermal treatment and lamination with rigid polymers, structural glass defies gravity, becoming beams, columns and suspended facades without any opaque frame.

01Thermal toughening and Heat Soak Test (HST)

To become load-bearing, ordinary float glass must be toughened. Heated to 700 degrees C and then rapidly air-quenched, the outer surfaces contract, trapping the core in a state of surface compression that triples bending strength (> 120 MPa). For structural use the HST (Heat Soak Test) cycle is mandatory, an oven test that safely shatters panes containing nickel sulphide impurities, guaranteeing in-service reliability.

02The SGP structural interlayer

Load-bearing glass is always laminated. Traditional PVB is soft and elastic: if the panes break, the panel sags and gives way. Structural glass uses rigid ionomer interlayers such as SentryGlas (SGP): 100 times stiffer and 5 times more tear-resistant than PVB. In the event of breakage, the SGP layer keeps the panel rigid and in position, preventing structural collapse.

Technical identity

Standards

European and international references applicable.

EN 12150 (Tempra)CNR-DT 210/2013 (IT)EN 12543 (Stratificati)

Physical properties

Bending strength (Float)45 MPa
Bending strength (Toughened)> 120 MPa
SGP vs PVB stiffnessSGP = 100x più rigido del PVB
Post-toughening operationsVIETATE (esplode istantaneamente)

Usage environment

Any hole, grinding or countersinking MUST be performed BEFORE thermal toughening. Once toughened, glass cannot be cut or drilled. Heat Soak Test (HST) is mandatory for structural use.

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