Wired glass is glass into which a fine metallic wire mesh has been cast during manufacture. When broken, the mesh holds the fragments in place, which is why wired glass was once widely used as fire- and burglar-resistant glazing in stores, basements, rooflights and industrial buildings.
How does wired glass work?
During production, a metal wire mesh is rolled between two layers of molten glass. As the glass cools, a single plate forms with the wires embedded. When the glass breaks, the shards stay attached to the mesh, reducing the immediate hazard from falling glass.
Types of wired glass:
- Polished wired glass — flat surface, transparent
- Patterned wired glass — with relief, such as obscured or figured glass
- Safety wired glass — with a finer mesh
Applications
Wired glass was used for:
- Fire-resistant partitions — internal walls and doors along escape routes
- Rooflights and skylights — as a safety glazing
- Industrial buildings — warehouses and factory halls
- Basement windows — as a burglar-resistant element
- School buildings — particularly in the 20th century
No longer a safety glass
Wired glass is now rarely used because:
- It is not classed as safety glass — for several decades it has not been accepted as a safety glazing. The wires can actually hold sharp shards in place, increasing the risk of injury
- Limited fire performance — modern fire-rated glasses are far more effective
- Aesthetics — the wire mesh is clearly visible
- Replaced by modern fire-rated and laminated glazing — such as pyrolytic glass or laminated glass with PVB interlayer
In new buildings, wired glass is hardly used today. In the restoration of listed buildings, it may still be specified to preserve the original appearance.
Related terms
Want to learn more about construction terms? Visit our knowledge base at fredsdiyplans.com.