Claims
- 1. In a fireproof glass pane which is resistant to high temperature and suitable for use as glazing in a room or space closure, the improvement wherein the pane withstands a fire test according to DIN 4102, (1970), STC1 (FIG. 1), for at least 90 minutes, the pane having a compressive stress in the marginal region, the product of heat expansion (.alpha.) and elasticity modulus (E) of the glass is 1-5 kp.times.cm.sup.- .times..degree.C., and the pane is capable of surface crystallization such that, when it is heated up in accordance with said DIN 4102 to just below the softening temperature of the basic glass, a continuous crystalline surface layer with a thickness of at least 5 .mu.m, forms.
- 2. Glass pane according to claim 1 having an upper devitrification limit of more than 800.degree. C.
- 3. Glass pane according to claim 1 having a compressive stress in the surface layer of the centre of the pane.
- 4. Glass panes according to claim 1 having a continuous, crystalline surface which is a 1-5 .mu.m thick, which does not impair its clearness.
- 5. Glass pane according to claim 1 rounded at the corners.
- 6. Glass pane according to claim 1 wherein the pane is round.
- 7. Glass pane according to claim 1 wherein the pane is bowed.
- 8. Building having a closure defined at least in part by a glass pane according to claim 1, mounted in a frame therefore.
Priority Claims (1)
Number |
Date |
Country |
Kind |
2424172 |
May 1974 |
DEX |
|
Parent Case Info
This is a continuation of application Ser. No. 577,481, filed May 14, 1975, now abandoned.
US Referenced Citations (8)
Foreign Referenced Citations (1)
Number |
Date |
Country |
739427 |
Oct 1955 |
GBX |
Continuations (1)
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Number |
Date |
Country |
Parent |
577481 |
May 1975 |
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