Fire-resistant Glass

Fire resistance can be built up in two ways. One is a laminated combination of Georgian wired glass and float glass (or safety or security glass) with a PVB inter-layer. The other way is to incorporate a transparent intumescent layer between the pre-stressed borsilicate glass sheets which, when heated, swells to form an opaque, fire-resistant barrier. Fire resistance of up to 2h can be achieved. It must be remembered that in any given situation, the performance of the glazing depends on adequate support during the ‘period of stability’ prior to collapse.


Areas of use: fire doors; partitions; staircase enclosures; rooflights and windows in hospitals; public buildings; schools; banks; computer centres; etc.


Normal glass is of only limited use for fire protection. In cases of fire, float glass cracks in a very short time due to the one-sided heating, and large pieces of glass fallout enabling the fire to spread. The increasing use of glass in multistorey buildings for facades, parapets and partitions has led to increased danger in the event of fire. In order to comply with building regulations, the fire resistance of potentially threatened glazing must be adequate. The level of fire resistance of a glass structure is classified by its resistance time: i.e. 30, 60, 90, 120 or 180 min. The fire resistance time is the number of minutes that the structure prevents the fire and combustion gasses from passing through. The construction must be officially tested, approved and certificated.

glazing with fire-protection class G

glazing with fire-protection class G

Fire-resistant glass comes in four forms: wired glass with point-welded mesh, maximum resistance 60-90 min; special armoured glass in a laminated combination with double-glazing units; pre-stressed borosilicate glass, e.g. Pyran; multi-laminated panes of float glass with clear intumescent interlayers which turn opaque on exposure to fire, e.g. Pyrostop.


Taken from: Architects’ Data by Ernst and Peter Neufert

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