Testing programmes for architectural safety glass cover four principal product categories: tempered, laminated, wired and burglar-resistant glazing. Each is assessed for optical, mechanical and environmental performance to verify fitness for façade and interior applications.
Tempered glass
Tempered glass is produced by heating flat glass to its softening point followed by rapid air quenching, or through ion-exchange chemical strengthening. The resulting surface compression increases bending strength by a factor of five to six, impact strength by roughly three and toughness by about five compared with annealed glass. On fracture it disintegrates into small, relatively blunt granules. Because it cannot be cut after treatment, all sizing and edging must be completed beforehand. Variants include polished and heat-absorbing tempered glass for doors, windows, partitions and impact-prone public areas; curved tempered glass is used for large commercial entrances, industrial rooflights and vehicular glazing.
Laminated glass
Laminated glass consists of two or more lites bonded under heat and pressure with a resilient interlayer. Substrates may be polished glass, float glass, tinted glass, heat-absorbing glass, heat-reflective glass or tempered glass. The interlayer holds fragments in place when broken, producing radial cracks rather than hazardous shards, and markedly improves impact resistance. Selection of different substrates and interlayer materials can also enhance resistance to light, heat, moisture and cold. Typical applications include high-rise and basement fenestration, bank façades, and display cases subject to collision risk.
Wired glass
Wired glass is manufactured by embedding a pre-heated metal wire or mesh into flat glass while it is in a red-heat softened state. The finish may be patterned or polished, and the glass clear or coloured. The internal reinforcement gives consistent stress distribution and impact resistance; if broken, fragments adhere to the mesh to prevent fallout. The embedded wires also retard flame spread. It is specified for vibration-prone industrial roofs and rooflights, fire-rated warehouse and library openings, composite building exterior walls and transparent barriers.
Burglar-resistant glass
This is a multi-ply laminated composite, typically combining tempered glass, extra-thick glass, strengthened organic glass or polished wired glass with resin interlayers. Conductive circuits and sensor elements are embedded within the stack and linked to alarm systems.
Test items
Inspection covers: appearance quality; dimensions and permissible deviations; bow and curvature; visible light transmittance (VLT); visible light reflectance; wind load resistance; heat resistance; moisture resistance; radiation resistance; ball impact peel performance; and shot-bag impact performance.