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Compare / Heat-strengthened glass vs Thermally toughened glass, enamelled

Heat-strengthened glass vs Thermally toughened glass, enamelled

Europe EN 1863-1 · Glass

Heat-strengthened glass

Float glass with moderate surface prestress: fb,k 70 MPa; breaks into large pieces that stay in the frame.

Europe EN 12150-1 · Glass

Thermally toughened glass, enamelled

Toughened glass with fired enamel (ceramic frit) on the surface: fb,k 75 MPa on the enamelled face.

Mechanical

PropertyConditionHeat-strengthened glassThermally toughened glass, enamelledDifference
Modulus of elasticity E—70 000MPa270 000MPa2same
Shear modulus G—29 166MPa229 166MPa2same
Poisson's ratio ν—0.220.22same
Knoop hardness HK—6GPa26GPa2same

Design values

PropertyConditionHeat-strengthened glassThermally toughened glass, enamelledDifference
Modification factor for load duration kmodinstantaneous load · wind gust, 3 s1111same
medium-term load · snow on heated buildings, 5 days0.4910.491same
permanent load · 15 years0.3210.321same
Partial factor for the material γMannealed glass part, γM;A1.811.81same
surface prestress part, γM;v1.211.21same

Physical

PropertyConditionHeat-strengthened glassThermally toughened glass, enamelledDifference
Density ρat +18 °C2 500kg/m³32 500kg/m³3same

Thermal

PropertyConditionHeat-strengthened glassThermally toughened glass, enamelledDifference
Coefficient of thermal expansion α20–300 °C9×10⁻⁶ /K29×10⁻⁶ /K2same
Specific heat capacity cp—720J/(kg·K)2720J/(kg·K)2same
Softening temperature Tso—725°C1725°C1same
Resistance to temperature difference ΔT—40K140K1same
Thermal conductivity λ—1W/(m·K)11W/(m·K)1same

Optical

PropertyConditionHeat-strengthened glassThermally toughened glass, enamelledDifference
Refractive index nvisible light, 589.3 nm1.511.51same
Emissivity εcorrected (for U-value calculation), uncoated0.83710.8371same

Electrical and magnetic

PropertyConditionHeat-strengthened glassThermally toughened glass, enamelledDifference
Electrical resistivity ρeat +25 °C · 1 000 Hz5 × 10⁷Ω·m15 × 10⁷Ω·m1same

Rows are matched by condition (thickness band, temperature, product form). A dash means the grade has no sourced value for that condition. Differences are Thermally toughened glass, enamelled relative to Heat-strengthened glass; for ranges the lower bound is compared.