Glass in 1970s: IGU sealed units · 449

Frozen silicate liquid — windows, bottles, fibres and a Euroclass A1 skin that still shatters and melts in fire. Glass is one of 32 materials in this atlas, grouped under ceramics: history, structure, measured properties, process routes, uses, safety and market — not a product catalogue.

Scores compare Glass with the rest of the atlas on strength, heat, fire behaviour, insulation, workability and circularity. They are editorial, not certificates. Seven chapters follow. Fire and insulation claims name test families (Euroclass, ASTM E84, ISO 5660, KS F) rather than inventing a single safety number.

Glass (SiO2–Na2O–CaO (typical soda-lime)) is a family of grades whose density ~2.5 g/cm³, heat band softens ~500–700 °C, and fire letter A1. Glass is sold as grades, not as a single substance. Chemistry SiO2–Na2O–CaO (typical soda-lime), density ~2.5 g/cm³, heat band softens ~500–700 °C.