Glass in 1674: Ravenscroft lead · 446

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.

This atlas treats Glass as a system: mill route, coatings, tests and the cavity it sits in. Conductivity note: ~1 W/m·K. Insulation score 28/100 is relative to 32 entries — metals lose, VIPs and aerogels win. Fire letter in editorial use: A1. Do not equate A1 with “safe in a blaze” or E with “illegal”. Assemblies decide.