Glossary

Ug value Unit of measurement for heat loss of glazing. The smaller the Ug value, the better the thermal insulation. Ug values determined for vertical installation as per DIN EN 673. For physical reasons, the Ug value of insulation glazing increases dependent on inclination angle when installed at an angle. g value Unit of measurement for total energy transmittance through glazing. High g value: Additional and free thermal use of sunshine. Low g value: Reduction of summer heating of rooms due to sunshine. Light transmission Degree of light transmittance in percent. Indicates the percentage of visible light (for the radiation band between 380 nm and 780 nm) that can pass through the glass and is therefore dependent on the glass thickness and coatings. The higher the light transmission, the greater the daylight utilization. Degree of light reflection The percentage of visible light (for the radiation range from 380 nm to 780 nm) that is mirrored or reflected on the glass pane surface. A high degree of light reflection means a reduction of glare inside the room. Ra value The general color reproduction index Ra describes the color impression that the human eye has when viewing an object illuminated by daylight coming through glazing. With clear glass, Ra is 99%. Shading coefficient (b-factor) Average transparency factor of solar energy, based on the total energy transmittance of a double glazing insulation glass, used to calculate the cooling load of glazed rooms. Shading coefficient (b factor) = g value / 0.80 (VDI 2078) Rw value Value for the sound insulation. The higher the sound insulation value, the better the sound insulation. In addition to the sound insulation value, the frequency of the sound source is taken into account with correction factors (C; C (C; Ctr) for good noise insulation. Facade panels Facade panels made of enamelled glass matched in color to the glazing. As color impressions are subjectively evaluated, sampling is recommended before specifying the glazing. The facade panels are mainly used to cover blank sections on buildings, e.g. ceilings.