Developments In Safety Glazing

Glazing, as per code: fireproof and wire-free, Architecture, April 2004, reports on changes in building code requirements for safety glazing in fire-rated applications. With the International Building Code (IBC), wire glass is no longer a permitted option for use in hazardous locations such as doors, sidelites, and areas close to the floor in fire-rated assemblies. It has long been recognized in the industry that wire glass does not fully meet impact requirements for use in hazardous locations, but until recently codes have included wire glass as an exception since there were few if any alternative glass products that had some degree of resistance to both impact and fire exposure. With new affordable, fire-resistant and impact-resistant glass products available, this is no longer the case and the exception for wire glass in these applications has been deleted.

Acceptable glazing products for fire-rated, hazardous locations include transpartnt glass ceramic and intumescent glass. Glass ceramic are single glazed products that meet both impact resistance requirements and provide up to a 3-hour fire resistance rating. Glass ceramic can also be provided in double-glazed assemblies for improved thermal or acoustical performance.

Intumescent glass are double-glazed products with an inner layer of transparent sodium silicate that, when exposed to high temperature, turns opaque and forms an insulating layer that can provide up to a 2-hour fire resistance rating. Unlike glass-ceramic, intumescent glass becomes insulating when exposed to fire. This property allows this product to meet the more strict fire test requirements for true fire-rated wall assemblies, not just for rated doors and windows. Thus intumescent glass products can be used over larger areas and offer potentially greater design flexibility. Intumescent glass is also more expensive than glass ceramic.

More Information
TGP Fire Rated Glass and Framing
Vetrotech
Pilkington