GB2281746A

GB2281746A - Fireproof glass pane

Info

Publication number: GB2281746A
Application number: GB9416107A
Authority: GB
Inventors: Viktor Lucius; Roland Leroux
Original assignee: Carl Zeiss AG
Current assignee: Carl Zeiss AG
Priority date: 1993-09-13
Filing date: 1994-08-10
Publication date: 1995-03-15
Anticipated expiration: 2014-08-10
Also published as: GB9416107D0; FR2710051A1; CH686434A5; FR2710051B1; GB2281746B; DE4331082C1

Description

2281746 FIREPROOF GLASS PANE AND A METHOD OF PRODUCING SAME The invention

relates to a fireproof, high-temperature-resistant glass pane in building-glass quality comprising a coated, prestressed soda-lime glass which, as a transparent component of a fire-protection glazing, withstands a fire test according to DIN 4102 or BS 476 for at least 30 m i n utes.

The invention furthermore relates to the method of producing such a glass pane and a fire-protection glazing consisting thereof.

There are various glasses and pane structures for fire-protection glazings, for example, of the fire-resistance class G according to DIN 4102 Part 13 or BS 476.

Originally, up to about 1970, wire-reinforced glass or glass blocks were used for fire-protection glazings. The wire-reinforced glass is used as cast glass or in superficially ground and polished form as wirereinforced mirror glass. Sealed into the centre of the pane is a spotwelded wire net which holds together the pane which has been cracked after exposure to fire and consequently prevents the passage of smoke and flames. A disadvantage in the case of wire-reinforced glass is that it does not have any safety-glass properties and can be used only to a limited extent in areas open to the public.

Fi. eTi-j;nrTS e-rxrvr.%r;r i- -1-s- bi"ilib -mIiefiiii]IF, j5 LL 3 LJAXJ-ixi clo- VYCABIA115i LL11M LIB'_y cannot be incorporated in doors, light-weight partitions and windows. They can be erected only as transparent walls.

2 In the mid-seventies, fire-protection glazings composed of borosilicate panes were introduced. Compared with fire-protection glazings employing wire-reinforced mirror glass, it was advantageous that no disturbing wire insert was needed. The higher softening point and the greater toughness of the glass made possible fire-resistance classes of up to 120 min. A disadvantage was that the panes were drawn by machine and consequently did not achieve mirror-glass quality. Furthermore, it was not possible to prestress them for fine granulation with conventional pretensioning installations; in this respect, they did not have any safetyglass properties, for example, in accordance with DIN 1249, Part 12.

In the eighties, panes composed of soda-iime glass were introduced for fire-protection glazings which had safety-glass properties. The panes had mirror-glass quality. Compared with the borosilicate glass panes they had disadvantageous properties such as lower softening point and lower toughness. For this reason, it was possible to use them only in special frame systems to a limited extent for the fire-resistance class G 30.

At the end of the eighties and start of the nineties, panes for fireprotection glazings were introduced which had infrared-reflecting coatings on one side. Only one side could be given an IR-reflecting coating for technological reasons. That had an unfortunate effect on the fire-resistance capacity. If the coated side of the pane was arranged to face the fire, the pane was able to withstand exposures to fire of over 60 min, but if the uncoated side of the pane was arranged to face the fire, tkn ILAI-IC chattered within a "A, minaltes ^f f; rem I -L&_7 _. lLkLL%-I%-%-4 VV ILI III I C& 1%.-VV 11 111 RUL cs, Ihe durattlon. The Ixyer, arranged on the room side acts as a heat trap for the fire-space radiation, i.e. the pane heats up significantly more rapidly and a thermal overloading is produced which results in the fracture of the pane. This 3 type of fire-protection glazing is completely unsuitable in practice since an incorrect installation is always possible at the building site.

Incidentally, DIN 4102 Part 13 requires the fire tests, for example for partitions, also to be withstood from both sides.

Recently, composite glass panes have been used for fire-protection glazings of the fire-resistance class G 30. The composite panes are of complicated structure. They comprise at least two panes and up to two different interlayers, one of which is an organic layer, for example a PVB film, in order to impart the properties of a safety glass to the composite. In practical versions, they cannot be used for fire-resistance classes higher than G 30.

Even in the mid-seventies, transparent glass-ceramic panes were officially tested as fire-protection glazings for a fire duration of 180 min. A disadvantage of the glass-ceramic panes is the low engineering strength since they cannot be thermally prestressed; they can be used only in frames having no, or very little, sag in the event of fire. Frames which have relatively large sag can cause the panes to shatter and, consequently, result in premature failure of the fire-protection glazings.

German Auslegesschrift 24 13 552 discloses fireproof glass panes which have a thermal strength which is so high that, as a space enclosure, they withstand a fire test according to DIN 4102 (1970) without cracking during the heat;mg-itm mk-3ca nr%f4 in +k mir;mknr-d reirT;m +ki:%%i -k- A%',:i -i -11 b V H1 "I SM It $ U 1%, fJ%,l IFI MA LLI I bl%Jl I Ll 1y I ILLV%, LA compressive stress and are composed of glasses whose product of thermal expansion (cc) and modulus of elasticity (E) is 1 to 5 [kgf x CM-2 X OC11.

4 The objective of German Auslegesschrift 24 13 552 are panes which have such a high thermal strength that, as a space enclosure, they withstand a fire test according to DIN 4102 (1970 edition), page 2, clause 5.2.4 or page 3, clause 4.3.2 for at least 30 min without cracking during heatingup and, in addition, do not need any wire inserts. In contrast to glass blocks, the thicknesses of the panes do not differ, or differ only insignificantly, from the pane thicknesses usual in building glazing.

Swiss Patent Specification 605 435 relates to a fireproof, hightemperature-resistant glass pane which, as a glazing in a space enclosure, resists a fire test according to DIN 4102 (1970) for at least 90 minutes without cracking and without exposing the space enclosure, and it has a compressive stress in the peripheral region, and is composed of glasses whose product of thermal expansion ((x) and modulus of elasticity (E) is 1 to 5 [kgf x cm-2x IC-1], and during heating-up according to DIN 4102, it forms a closed crystalline surface layer.

The Swiss patent specification requires glass panes which are of special composition and are therefore relatively expensive; the establishment of a compressive stress only in the peripheral region of the glass pane is also expensive to achieve.

WO 93/07099 describes a fire-resistant glass pane which is heat-treated to increase its strength and which has, at least on one of its surfaces, a 4"; onnor-h i '- - - - -p t.

fk;n Inwiar of a composition wh,',, Is OLUb'11- U %J L%_111tJ%_1CALU1%_J %-,I aww and remains joined to the surface so that the coated pane is not destroyed up to temperatures of 9000C, the edges of the glass pane being ground in order to eliminate faults prior to the heat treatment.

The pane according to WO 93/07099 has only one surface coating, which is preferably applied to the glass by relatively expensive methods, such as sputtering, plasma coating or CVD.

German Application P 42 06 514 of the Applicant describes a pane structure for a fire-protection multiple glazing which comprises at least two panes which are arranged at a distance from one another and of which at least one pane is prestressed, at least one prestressed pane being provided on one side with an infrared-reflecting layer which is arranged so as to face the further pane.

The object of the present invention is to provide a pane which has higher exposure times in the event of fire than a conventional pane and in mirror-glass quality has toughened safety-glass properties, for example according to DIN 4102 Part 12 or BS 6206. It should resist fire from both sides in fire-protection glazings.

Furthermore, the object of the invention is a further, appreciable improvement in fire-protection glazing based on prestressed soda-lime float glass.

According to the present invention, the object is achieved in that the glass pane has a layer of TiO, or Zr02which is in turn completely covered by an S'02 1 aye r.

Essential tn tkca in,.túinfir%n;c tP.%ci f-ne-f that a coda-lim.. pane having r-n;rrr-tr- --- 11 ---.... -1 -- 1.1 1. $- 1-L 11 9"1 " _ 9 4. 1 --- glass quality is coated with thin layers of T'02 or Zr02, andS'02 and is then prestressed. In a suitable frame system, the pane coated in this 6 manner withstands the temperature rise in accordance with the standard time-temperature curve (STC) of DIN 4102.

The layers are applied to both sides by the immersion method and then baked in. The Ti02 or Zr02 layer thickness may be from 20 to 600 nm. Preferably, however, Ti02 or Zr02 layer thicknesses of 60 nm to 130 nm are used. The Ti02 or Zr02 layers are combined with an S'02 top layer. TheS'02 layer, which is preferably 90 nm thick, has an antireflection effect on the coated panes and substantially improves the optical appearance of the panes.

The immersion method used in the present invention is described in detail in German Utility Model 74 29 287.

In the event of fire, the Ti02 or Zr02 layers react with the soda-lime glass. They alter the physical properties of the glass and reinforce the panes.

In this connection, in the event of fire, the Ti02 or Zr02 layer reacts with the surface of the soda-lime glass with partial mixing, in which process ions of at least one of the elements sodium, calcium or magnesium diffuse out of the glass into the TiO, or ZrO, layer and ions of titanium or zirconium diffuse into the glass.

As a result of the reinforcement of the panes, the fire resistance is increased nnrl rlinndanr4incy nn the pane size nvn^ctirm t;rnne nf > 6n min can be achieved.

7 According to experience, even the slightest doping of the Ti02 or Zr02 layer impairs the reinforcing action on the soda-lime glass. The Ti02 or Zr02 layer therefore contains less than 0.2% by weight of impurities.

The panes coated on both sides with Ti02 or Zr02, andS'02 can be installed completely symmetrically. In the event of fire, the Ti02 layer or Zr02 layer reacts with the soda-lime glass to reinforce the pane. The reaction mechanism has not yet been precisely clarified but diffusion processes are assumed which possibly result in the reinforcement of the pane in connection with theS'02 layer. The reinforcing action of the layers makes possible a smaller rabbet allowance (or overlap) than in the case of uncoated soda-lime glass since the layers have an action which increases exposure time. As a result of the reinforcing action of the layers, the frame structures for fire-protection glazings can be designed more simply and, consequently, less expensively and more reliably. Furthermore, larger pane sizes can be achieved.

The soda-lime glass panes for fire-protection glazings marketed at present require, for example, a rabbet allowance of 8 to 12 mm, while the pane produced according to the invention requires only a rabbet allowance of 5 to 10 mm.

The exposure times achieved in the fire experiment are, as a rule, appreciably over 45 minutes, for example, for a G 30 glazing.

The Metho-1 --cing fim-proof glass por-Anes raccording +to thC _ of prod. invention is preferably conducted so that the layers are applied on both sides, in particular using the immersion method as described, for example, in German Utility Model 74 29 287. The layers applied using 8 the immersion method are then baked at, preferably, 4000C and the coated glasses are prestressed, a prestress of between 60 and 160 N1mrn', in particular between 80 and 120 N/mM2 being established.

The coated soda-iime glass is thereby prestressed in accordance with DIN 1249 Part 12. The panes produced in this way for fire-protection giazings have toughened safety glass properties and the surface has mirror-glass quality.

The invention is further explained below with reference to the drawing and an associated exemplary embodiment:

A float-glass pane which is obtained from the producer, for example, in a size of 3.75 x 3.21 m is immersed in a cuvette in accordance with German Utility Model 74 29 287. The cuvette contains an alcoholic chloroethyl titanate solution containing 30 - 50 g/1 Ti02. The pane is then drawn out of the solution at a speed of 5 - 10 mm/s. The liquid solution adhering to the pane is baked in a furnace at 4001C. During baking, the titanium contained in the solution forms a thin Ti02 layer 110 - 120 nm thick on the pane. Then the SiO, layer is applied to the Ti02. The cuvette now contains an alcoholic silicic acid ester solution containing 15 - 22 g/1 SiO,. The pane is then drawn out of the solution at 4 - 9 mm/s. The liquid solution adhering to the pane with the Ti02 coating is then likewise baked at 4000C. An 85 - 95 nm thickS'02 layer is formed.

A 1 m x 2 m pane is then cut from the large pane, edge-machined (DIN 1249) and thermally prestressed in a conventional installation.

9 The prestress is produced by methods known in the prior art, in general by heating up the glass panes in a furnace to temperatures which are above the transformation point (Tg) and subsequent blasting with cold ai r.

A glazing example is described in the figure below (Figure 1).

The glazing comprises the 6 mm x 1 m x 2 rn pane (2) which is coated on both sides with approximately 115 nrn thick Ti02 and approximately 90 mm thickS'02 and which was thermally prestressed at approximately 100 N/m M2. The glazing is mounted in a steel frame (5) by means of padding (6) and rabbet seals (7), which steel frame (5) comprises rectangular tubular steel sections (3) and (4) and is welded or screwed together.

The glazing described was subjected to a fire test in accordance with DIN 4102 or BS 476. The pane did not slip out of the frame until over 60 min of fire time had elapsed and freed an opening, as a result of which the space closure effectiveness was no longer fulfilled.

The same fire test performed with a pane which was coated on both sides with Zr02 60 - 80 nm thick and which was also completely coated with an approximately 90 nm thickS'02 layer achieved a fire resistance time of over 50 min.

When tested in WN-kniKI Alf)'), '3 CTI'1'7;Mfl 1Aik;fk was as L.. - I I, I I " bl"l 1 16 VV I I I --.I I vy " described but having an uncoated 6 mm x 1 m x 2 rn soda-lime glass pane achieved only a fire-resistance time of 32 min

Claims

Claims: V_

1 A fireproof, high-temperature-resistant glass pane in buildingglass quality comprising a coated, prestressed soda-lime glass which, as a transparent component of a fire-protection glazing, withstands a fire test in accordance with DIN 4102 or BS 476 of at least 30 minutes, characterized in that at least one side of the glass pane has a layer of Ti02 thereon which is in turn completely covered with anS'02 layer.

2. A fireproof, high-temperature-resistant glass pane in buildingglass quality, comprising a coated, prestressed soda-lime glass which, as a transparent component of a fire-protection glazing, withstands a fire test in accordance with DIN 4102 or BS 476 of at least 30 minutes, characterized in that at least one side of the glass pane has a layer of Zr02 thereon which is in turn completely covered with anS'02 layer.

3. A fireproof glass pane according to Claim 1 or 2, characterized in that the TiO, or ZrO, layer has thicknesses of 20 - 600 nm, in particular of 60 - 130 nm.

4. A fireproof glass pane according to Claim 1 or 2, characterized in that the SiO, layer has thicknesses of 80 - 100 nm, in particular of 90 nm.

5. A fireproof glass pane according to any one of Claims 1 to 3, rhararteri7PH in th;it thp Tin- or 7rn lay r contains less than 0.2% by e. weight of impurities.

11

6. A fireproof glass pane according to any one of Claims 1 to 5, characterized in that, in the event of fire, the TiO, or ZrO, layer reacts with the soda-lime glass to reinforce the pane.

7. A glass pane according to any one of Claims 1 to 6, wherein the Ti02 or Zr02 layer and theS'02 layer are provided on each side of the pane.

8. A method of producing fireproof glass panes according to any one of Claims 1 to 7, characterized in that the layers are applied to the sodalime glass, in particular on both sides, in particular using the immersion method.

9. A method according to Claim 8, characterized in that the layers applied using the immersion method are baked at 3600C to 4801C, in particular at 4001C.

10. A method according to Claim 7 or 8, characterized in that the coated glasses are thermally prestressed.

11. A method according to Claim 10, characterized in that a compressive prestress of between 60 and 160 N/m M2, in particular of between 80 to 120 N/m M2 is established.

12. A fire-protection glazing comprising a frame having a rabbet which. ils formed by gdass-hold1ng, -trips and in which at least one fireproof, high-temperature-resistant glass pane according to any one of Claims 1 to 7, produced according to any one of Claims 8 to 11, is 12 installed using seals by means of clamping means disposed in the edge region of the pane.