Glossary – our knowledge from A to Z

Obsolete German expression for thermal transmittance. See: U-value.

Designation for a cut glass edge without edge working. The typical wavy lines of the cutting tool are still visible and there may be undercut or overcut. Such a cut edge is extremely sharp: risk of injury!

Designation for edge working to DIN1249 in which the entire edge of the glass is processed. The edge has a matt ground appearance, the arrisses are chamfered.

A form of edge working to DIN 1249. It designates a cut glass edge, the arrisses of which have been swiped with a grinding tool.

Steel cast with deoxidising agents (Si, Mn, Al) or following vacuum treatment. Owing to the addition of the deoxidants, it solidifies in the mould without boiling, without spraying sparks.

Designation for a ground straight edge that is polished to improve the quality of the surface. Polishing marks that can be seen and felt are permissible, but there should be no matt areas.

A colourless, odourless noble gas that does not form chemical compounds with any other substances. When used in the cavity of double glazing, it can reduce the U-value of the panes by approx. 0.4 W/m²K. The low thermal conductivity of krypton enables the width of the cavity to be reduced.