Fire Protection: Glazing. Door Glazing

Alternatively, this type of glazing may also consist of three or four silicate glass panes, laminated with fire protection layers of gel containing an inorganic compound. These layers provide the fire retarding effect. The gel itself is formed from a polymer, in which the inorganic salt solution is embedded, which is highly water-retentive.

In the event of fire, a thermal insulation layer forms and considerable amounts of energy are absorbed through the vaporisation of the water. This process repeats itself, layer by layer, until the gel in the intermediate layers between all of the panes has been dissipated. In this way, fire resistance times of 30, 60, 90 minutes and longer are achieved.

The gel layers in this heat radiation resisting glazing can only tolerate temperatures between -15°C and +60°C. With regard to temperatures above the permitted upper limit of +60°C, application in individual cases must be decided on the basis of the orientation of the fagade to the sun and whether the absorption of radiation by the gel might result in the temperature limit being exceeded. If necessary, the intensity of radiation from the sun must be reduced through the use of protective glass or by other shading precautions. However, as a rule, such precautions are not necessary.

These glazing systems usually have special steel glazing bars, which are thermally isolated, and the surfaces of the frames can be faced with aluminium, if required.

The typical maximum height is 3.50m, with a maximum individual pane size of 1.20 x 2.00m. There is also the possibility of replacing individual panes of glass with nonload bearing panels.

Fire resistant glazing without heat radiation resistance. These are light transparent components that can be arranged vertically, horizontally or be inclined. They are suitable as fire protection glazing to impede the propagation of fire and smoke according to their fire resistance period. They do not, however, prevent the passage of radiated heat. This type of glazing remains transparent in the event of fire and is as effective as glass for fire protection.

Glazing without heat radiation resistance reduces the temperature of the radiating heat by about one half as it passes through the pane.

This grade of fire resistance can be achieved by three different types of glass:
(1) Wire reinforced glass with spot welded mesh such that in the event of breakage the glass pane is retained by the wire mesh. Maximum resistance up to 90 minutes.
(2) Special ly manufactured double glazing units. Maximum resistance up to 60 minutes.
(3) Pre-stressed borosilicate glass (for example, Pyran). Maximum resistance up to 120 minutes resistance as a single pane.

The installation of this type of glazing in the facades of high buildings can prevent the spread of fire from one level to another. This applies especially to high-rise buildings which are subdivided into horizontal fire compartments. On buildings with inside corners, an unimpeded spread of fire can occur in the region of windows but this can also be avoided by using this type of glazing.

Generally, glazing without resistance to heat radiation should only be installed in places which do not serve as an escape route (for example, as light openings in partition panels). If used adjacent to escape routes, the lower edge of the glass should be at least 1.80 m above floor level. The permitted use of this glazing must be decided on an individual basis by the relevant local building authority.

Door glazing. The frames for fire protection glazing, together with the light transparent elements (glass), ensure integrity according to grade of fire resistance in the event of fire. The following materials (and material combinations) have proved to be suitable for the construction of frames:
- steel tube sections with an intumescent protective coating
- plasterboard and wood with, for example, light metal (LM) facings
- light metal sections with fire resistant concrete cores
- heat radiation protected LM laminated sections
- combined sections: concrete outside (paintable), inside of LM, sections of pre-cast concrete (paintable), hardwood sections, heat insulated profiles with steam relieved interstitial air gaps and light metal with fire resistant and penetration resistant concrete cores.