A detailed guide covering the main families of architectural glass and proper selection criteria based on use location.
From Raw Float Glass to Processed Glass Families
Every type of architectural glass starts as raw, untreated float glass, which isn't suitable for direct use in facades or doors because it shatters into sharp shards on impact. Through thermal or chemical treatments or added coatings, this raw material transforms into specialized families: safety glass (tempered or laminated), performance glass (Low-E or heat-absorbing), and decorative glass (frosted, colored, or printed). Understanding this sequence helps the design team specify the correct treatment for each location in the building instead of treating glass as one uniform material.
Safety Glass: Tempered and Laminated
Tempered glass undergoes heat treatment that increases its strength four to five times, breaking into small, blunt fragments on impact, which is why most engineering codes mandate it for doors, balustrades, and direct-contact zones. Laminated glass consists of two or more layers separated by an adhesive interlayer (PVB or SGP), holding together even after breaking — the mandatory choice for upper floors and glazed skylights, where a falling pane poses a real hazard to pedestrians below the building.
Performance Glass: Low-E and Insulated Units
Low-emissivity (Low-E) glass carries a thin metallic coating that reflects infrared radiation and reduces heat gain without noticeably affecting visible light transmission. When this glass is combined into an insulated glass unit (IGU) with an air gap or inert gas fill between panes, thermal and acoustic performance rises sharply compared to any single pane, making it the baseline standard in modern residential and commercial facades pursuing higher energy efficiency.
International Standards Worth Verifying
Before approving any glass specification, it's advisable to review test certificates against the relevant international standards: European EN 12150 for tempered glass, EN 14449 for laminated glass, American ASTM C1048 for tempered glass, ASTM E2190 for insulating glass units, and EN 410 for determining the optical and thermal properties of glass. Requesting these certificates from accredited laboratories protects the project from undocumented performance differences between manufacturers.
How to Read a Glass Specification on a Technical Drawing
A glass specification is typically written as a combination of each layer's thickness with the gap or interlayer type, such as "6mm tempered Low-E + 12mm air gap + 6mm tempered," and every figure in that formula directly affects performance and cost. When reviewing any quotation, confirm the written specification exactly matches what the design consultant approved in the drawings, since even a small change in thickness or layer type shifts the system's actual performance entirely.
