EP0568458B1 - Fire-protective glass constructional element - Google Patents

Abstract

The invention relates to a fire-protective glass constructional element comprising at least one fireproof glass pane whose periphery rests in the rebate of a frame. The said periphery is held in its rebate, at least along its upper and especially horizontal edge, by interposition of a fibrous material (6) which has a high porosity and modulus of elasticity and whose properties and/or structure are maintained unchanged at high temperature, the latter material penetrating into the glass pane when the latter approaches or reaches its softening temperature. <IMAGE>

Description

The invention relates to a glazed fire protection element, and more particularly designated by the term "flame arrester" intended to delay the propagation of a possible fire either from one floor to another when it equips the facade of a building, either from one room to another when it is part of an internal partition of a room.

This type of glazing has the property of remaining in place during a fire, and thus preventing the passage of smoke and hot gases for a period of time significantly longer than in the case of standard glazing, its performance in terms of fire resistance which can in particular be assessed by the tests described in standards ISO 834 and ISO 3009.

However, the production of flame-resistant glazing faces in particular two types of technical problems: these glazings usually consist of at least one toughened glass substrate, and retained at their periphery in the rebate of a generally metallic frame. It is therefore first of all necessary to avoid an early rupture of the glass substrate (s), rupture resulting from the thermal stresses generated from the start of the fire, in particular by the temperature gradient between on the one hand the periphery of the "masked" glazing and in the rebate, and on the other hand the rest of the glazing exposed directly to the fire.

This is why US Pat. No. 4,178,728 in particular proposes a profile defining the rebate bottom and maintaining the periphery of the glazing on the "outside" side of the building once the glazing is installed. The second "internal" side, that is to say oriented towards the interior of the room, being coated and masked by a mechanical part which is removable under the action of heat: Thus, during a fire, the Falling of this piece exposes the periphery of the "internal" edge of the glazing to fire, thus limiting the thermal gradient between edges and center of the glazing and therefore the risk of explosion from the start of the fire.

This profile does not, however, solve the second problem that appears when the fire has started for a certain time and the glass begins to approach substantially its softening temperature: Indeed, the glazing then tends to collapse under the effect of its own weight, greatly stressing the means of fixing its upper and / or lateral periphery in the rebate. A French patent FR-B-2 282 033 thus proposes to slow down the sagging of the glass by interposing between the periphery of the glazing and the edges of the rebate a mineral material such as glass strips which, at high temperature, then join the rebate glazing.

None of these embodiments is however fully satisfactory insofar as they do not simultaneously solve the two problems mentioned above.

The object of the invention is then to obviate these drawbacks by producing a flame-resistant glazing capable of being used to equip facades and / or internal partitions of buildings, which has improved fire resistance while being implemented. simple. The invention also aims to develop the use of material capable of more effectively maintaining the glazing in its rebate in the event of fire.

The fire-resistant glazed element according to the invention comprises at least one flame-resistant glazing whose periphery rests in the rebate of a frame, said periphery being maintained in its rebate, at least along its upper edge, in particular horizontal, by interposing a fibrous material with high porosity and modulus of elasticity, the properties and / or structure of which are unchanged at high temperature, the latter delaying the fall of said substrate by penetrating into it when the latter approaches or reaches its softening temperature. Preferably, the fibrous material according to the invention has a porosity at least 50% and the elastic modulus of the fibers and / or yarns is at least 150,000 MPa.

The flame-retardant glazing in question may consist of a monolithic glass substrate, or of a plurality of monolithic glass substrates associated by means of interlayer materials, such as for example interlayer sheets based on polymers and / or gel-type materials with fire-resistant properties.

These different substrates can also be associated with multiple glazing by means of gas plates.

The substrates can thus be based on soda-lime-silica glass tempered to obtain a certain level of pre-stress, or based on glass with a low coefficient of thermal expansion such as those described in the request for certificate of addition FR- 2,271,181 and / or based on borosilicate glass as described in patent FR-2,389,582.

As an example of laminated glazing, mention may be made of triple laminated glazing described in European patent application EP-0 219 801.

The glazing can also be reinforced, that is to say have a double-glazing structure comprising a wire mesh welded by points, as described in French patent FR-1,590,983.

Said flame-resistant glazing can also be part of a fire-resistant glazing, as mentioned above.

The invention thus operates a judicious compromise: by choosing a fibrous material with high porosity, it is possible for the edges of the glazed element, even if they remain partially masked by the wall of the rebate, to be in direct contact with a material that does not obstruct heat by its texture. This limits the thermal gradient between edges and center of the glazing at the start of a fire in particular. It is also possible to choose the fibrous material so that it is also a good conductor of heat, a property which makes it possible to further accentuate the limitation of thermal gradient. Preferably, it has a conductivity of at least minus 15 Watts m ^-10 C ^-1 .

On the other hand, when the glass begins to soften and collapse, it remains securely held in place by the action of the fibrous material which effectively grips the glazing, because it resists high temperature without modification of structure and / or properties and that it is of a fibrous nature and can therefore "become encrusted" partially in the thickness of the softened glass to better retain it. In fact, thanks to its high modulus of elasticity, this material has, even and above all at high temperature, good mechanical strength combined with an ability to be compressed without permanent deformation, which gives it a "spring" effect which retains the substrate at like a clamp, but more effectively, since, being fibrous, it can partially penetrate the softened glass much more easily.

Preferably, this fibrous material also maintains in the rebate the lateral edges, in particular the vertical edges of the glazed element, which tend to collapse together with the upper edge.

The most advantageous is to pinch in its rebate the edge or edges of the glazing using this fibrous material on each of its faces. It thus retains the glazing as well as possible while ensuring good wedging of the edges of the glazing in the rebate.

This fibrous material is for example essentially metallic, in particular based on stainless steel or copper. Choosing a fibrous material of a metallic nature is indeed advantageous, because the material is then both a good thermal and electrical conductor. In addition, it can then be easily fixed in the rebate by welding, which avoids the need for adhesives whose resistance to fire may not be optimal.

It can in particular consist of fibers assembled in the form of a braid and then wrapped with a thread of similar nature. These fibers, obtained in the form of a sort of "chip" by pulling out from thick and continuous unitary threads in a known manner, have diameters preferably between 10 and 100 micrometers and are relatively long, with a length that can even be several meters.

This material can also consist of threads assembled in the form of a tubular knit, in particular with a diameter between 100 and 500 micrometers.

In the case of braids composed of fibers, as the fibers have an orientation disorganization, said braids have a good elasticity perpendicular to their main axis, due to both the high porosity of the material and the great length of the fibers.

In the case of tubular knitting, it is the mesh which gives this elastic character contributing to the "spring" effect previously mentioned and specific to the invention.

If, in addition, it is necessary to guarantee the sealing, in particular with water, of the bottom of the rebate, the spaces defined by the walls of the rebate are provided on either side of the glazed element and "by above "this fibrous conductive material, of a silicone seal type resistant to fire.

Any suitable mechanical and / or adhesive means can be used to retain the conductive fibrous material in the rebate. It is possible, for example, to provide at least one of the edges of the rabbet with a spoiler which protrudes and / or provide to provide at least one of the edges of the rabbet with pins distributed in particular on a strip welded to said edge. This material can also be provided on its outer surface with an adhesive resistant to high temperatures, such as a mineral glue, for example silicate. One can also provide a rebate whose contact surface with said fibrous material has roughness capable of retaining it. If it is metallic, it can also simply be welded, as already mentioned. All these means can be used individually or in combination, and fulfill their role of maintaining not only at normal temperature but also and especially in the event of fire, so that the fibrous material remains correctly in place in the rebate to retain the (s) glass substrate (s).

It is also possible to provide the rebate bottom, at least in the area where the edge of the lower edge of the glazing rests, with wedging and sealing means, in particular at the air known to art.

The implementation of the invention is quite simple: Thus, insofar as the frame defining the sheet comprises a mechanical section associated by mechanical means with a glazing bead, it suffices to correctly wedge the glazing in the section using the fibrous conductive material, then forming the rebate by applying the glazing bead.

It should be noted that this fibrous material, which has, by its texture, a relative flexibility even if it is however relatively soft, allows a possible relative deformation between the glazed element and its frame, and in particular a slight warping of the 'glazed element on the one hand, its frame on the other hand, which limits the mechanical stresses and contributes to an increase in the fire resistance of the glazed element.

The glazed element designed according to the invention has a high fire resistance, and in particular at least 30 minutes according to the ISO 3009 standard.

• fig. 1 : une coupe transversale de la périphérie de l'élément vitré dans sa feuillure, une fois installé en position verticale dans un bâtiment.
• fig. 2 : un élément de cloison utilisé pour l'étude de son comportement au feu selon la norme ISO 3009.

The details and advantageous characteristics of the invention appear from the following description of a nonlimiting embodiment, using the following figures:

• fig. 1: a cross section of the periphery of the glazed element in its rebate, once installed in a vertical position in a building.
• fig. 2: a partition element used for the study of its fire behavior according to ISO standard 3009.

The glazed element 1 itself consists of a flame-resistant glazed element, for example of a monolithic substrate made of soda-lime-silica glass 6 millimeters thick and thermally toughened so as to present a level of stress suitable, in particular at least 120 MPa. Its entire periphery is held in a rebate determined by a metal profile 2 associated with a glazing bead 3. The association is carried out here by two complementary mechanical means: on the one hand, the tongue 10 present on the glazing bead 3 is blocked in the cavity 9 of the profile 2. On the other hand, a screw 11 is provided to screw the glazing bead 3 to the profile 2 and thus complete the plating of said pareciose against the latter, preventing any risk of tilting of the glazing bead 3. The edge 4 of the glazing 1 rests at the bottom of the rebate on one of the means 5 of wedging and airtightness. Between the two faces of the glazing on its periphery and the side walls of the glazing bead 3, is interposed a conductive fibrous material 6 composed of fibers with a diameter of approximately between 50 and 100 micrometers made of stainless steel 430 according to the AISI standard, assembled in a braid with a grammage of 70 g / m linear, of approximately rectangular section, of approximately 10 x 6 mm ² . This is wrapped in a wire of the same metal 3 / 10th of a millimeter in diameter. This braid has a porosity of approximately 76%, the stainless steel which constitutes it has a modulus of elasticity of approximately 200,000 MPa and a thermal conductivity of approximately 20 watts.m ^-1 . ° C ^-1 . This braid is preferably provided on its faces in contact, on the one hand with the glass, on the other hand with the walls of the rebate, of a thin film of adhesive resistant to high temperature of the silicate glue type. It is also here covered on its face turned towards the outside of the rebate with a fire-resistant silicone gasket 7. This avoids any infiltration, especially of water, inside the rebate. The braid 6 interposed between the substrate 1 and the glazing bead 3 is held in place using a spoiler 8 present on the glazing bead 3. The braid 6 which is interposed between the substrate 1 and the profile 2 is held in place at using a strip of thin sheet metal provided with regularly spaced spikes (not shown) on the periphery of the profile 2, spikes which need only be folded down to retain said braid.

The assembly is therefore easily done by placing the substrate 1 in the frame 2 provided with its appropriate wedging means 5 and its first layer of conductive fibrous material 6 Interposed between substrate 1 and frame 2, then, by compression, by wedging the tongue 10 in the cavity 9 then by screwing the glazing bead 3 by interposing a second layer of fibrous conductive material 6. The substrate is then perfectly wedged in its rebate.

However, this arrangement allows a certain amplitude movement and / or thermal expansion between the substrate 1 and the profile 2 and the glazing bead 3, which allows a relative relaxation of the thermal stresses that the glass substrate undergoes in particular when a fire breaks out, and therefore limits the risks of rupture .

When the substrate 1 begins to collapse, if it can warp slightly, it remains gripped by the material 6 which slows down its fall.

• vitrage 12 : 1680 x 1720 cm²
• vitrage 13 : 1680 x 1048 cm²
• vitrage 14 : 1088 x 1720 cm²
• vitrage 15 : 1048 x 1088 cm²

The thermo-mechanical behavior of a partition element according to the invention is described below according to ISO 3009 and ISO 834 standards. This is in fact separated into four separate glazings 12, 13, 14, 15 shown very schematically in Figure 2; all comprising a monolithic substrate fixed in its rebate as previously defined. The dimensions of 4 glazings are specified below:

• glazing 12: 1680 x 1720 cm ²
• glazing 13: 1680 x 1048 cm ²
• glazing 14: 1088 x 1720 cm ²
• glazing 15: 1048 x 1088 cm ²

The temperature rise (T-TO in degrees Celsius) during a standardized test meets the following law: $${\text{T-TO = 345 LOG}}_{\text{10}}\text{(8 t + 1)}$$

The temperature T to be considered is a function of the duration t (in minutes) during which fire resistance must be ensured.

This "complex" partition element formed by the 4 panes 12-15 is therefore placed in an oven, one of the faces of these 4 panes being directly exposed to its heat while the others are in contact with the ambient atmosphere.

During the first 10 minutes of the test, the oven temperature goes from ambient temperature TO to a temperature of the order of 680 ° C. Each of the faces of the glazing units which is exposed to this rise in temperature undergoes sudden heating and expands, inducing in the glass a series of thermal stresses, due first of all to an immediate thermal gradient in the thickness of the glass, gradient having tendency to bend the glazing so as to have a concavity on the side of the face not exposed to the heat of the oven. Another thermal gradient is also created on each of the faces directly exposed to heat, extending in the plane of these faces the edges of the glazing protected from overheating by glazing beads. We can consider that the thermal gradient in the plane of glazing 12-15 reaches its maximum after 5 to 10 minutes.

From 10 to 20 minutes after the start of the test, the thermal gradient in the plane of the glazing tends to decrease, the substrates starting to lose their level of prestress imposed by thermal quenching. The frames gradually heat up, creating differential movements between the glass substrates and these.

Beyond 20 minutes, it can be considered that the glass substrates have reached their "tempering" temperature.

Beyond 30 minutes, the glass of the substrates approaches its softening temperature, it tends to creep and it is therefore during this critical period that the fibrous material 6 fully fulfills its role, both on the upper edge and on the lateral edges of each glazing 12-15. This effectively retains the glazing in place, which eventually collapses, starting with the glazing 12 of larger dimensions, but only beyond 40 minutes after the start of the test. It should be noted in this connection that the opening in the glazing begins not at the periphery of the horizontal upper edge thereof which is located in the rebate, but below the rebate, which highlights the effectiveness of the gripping action of the fibrous material 6 according to the invention.

It should also be noted that the fibrous material according to the invention also applies effectively in the case where the profile is no longer metallic but wooden. Wood, under the action of fire, burns slowly without deforming, unlike metal, this is the reason why it is preferred, in this case, to provide a thicker fibrous material so that the rigidity of the wood is also compensated by an increased compression capacity fibrous material. This avoids subjecting the glazing to additional mechanical stresses.

In conclusion, the fixing of a fire-resistant glazed element in the rebate of a frame according to the invention, that is to say by a fibrous material which has a certain adaptability due to its porosity and its compressibility, is particularly simple. Nevertheless, it appreciably increases the fire resistance of the glazing both by helping to reduce the thermal gradients in the glazing created by the fire, by allowing a certain clearance between glazing and rebate while firmly maintaining the glazing, and finally and above all by retaining the glazing when it tends to collapse by softening.
The embodiment of the invention consisting in using a metallic material also makes it possible to simultaneously ensure mechanical, thermal and possibly electrical contact between glazing and rebate.

Claims (24)

1. Fire-resistant glazed element (1) comprising at least one flame-arrester pane, the periphery of which rests in the rebate of a frame (2), characterized in that said periphery is held in its rebate, at least along its upper, notably horizontal edge, by the interposition of a fibrous material (6) of high porosity and high modulus of elasticity, the properties and/or the structure of which are maintained unchanged at high temperature, this material penetrating into the pane when the latter approaches or reaches its softening temperature.
2. Glazed element (1) according to claim 1, characterized in that the fibrous material (6) has a porosity of at lest 50%, notably approximately 76%.
3. Glazed element (1) according to claim 1 or 2, characterized in that the fibres of the fibrous material (6) have a modulus of elasticity of at least 150,000 MPa.
4. Glazed element (1) according to one of claims 1 to 3, characterized in that the fibrous material (6) is a heat-conducting material having, notably, a thermal conductivity greater than 15 watts.m^-1.°C^-1, and notably of approximately 20 watts.m^-1.°C^-1.
5. Glazed element (1) according to one of claims 1 to 4, characterized in that the fibrous material (6) is essentially of metallic nature, notably based upon stainless steel or copper.
6. Glazed element (1) according to one of claims 1 to 3, characterized in that the fibrous material (6) is constituted of fibres assembled in the form of braids, then wrapped with a wire of similar nature, or of threads assembled in the form of tubular knitting.
7. Glazed element (1) according to one of claims 1 to 6, characterized in that the fibrous material (6) is interposed also in the rebate on the lateral edges, notably vertical edges, of the glazed element (1; 12-15).
8. Glazed element (1) according to one of claims 1 to 7, characterized in that the fibrous material is interposed on the edge or edges of the glazed element (1; 12-15) in the rebate on both of its faces.
9. Glazed element (1) according to one of claims 1 to 8, characterized in that the spaces defined by the rebate on either side of said glazed element are provided, beyond the conducting fibrous material (6), with a seal (7) notably against water, for example of the fire-resistant silicone type.
10. Glazed element (1) according to one of claims 1 to 9, characterized in that the fibrous material is retained in the rebate of the frame by mechanical means, such as an overlay (8) projecting beyond at least one of the edges of the rebate and/or a succession of barbs, notably welded into a metal strip present on at least one of the edges of the rebate.
11. Glazed element (1) according to one of claims 1 to 10, characterized in that the fibrous material (6) is retained in the rebate by adhesive means resistant to high temperature, such as a mineral glue, for example silicated mineral glue.
12. Glazed element (1) according to one of claims 1 to 11, characterized in that the fibrous material (6) is retained in the rebate by means of rugosity present on the contact surface of the rebate with said fibrous material.
13. Glazed element (1) according to one of claims 1 to 12, characterized in that the frame comprises a metal profile (2) which, associated by mechanical means with a closure strip (3), defines the walls of the rebate.
14. Glazed element (1) according to one of claims 1 to 13, characterized in that the flame-arrester pane is a toughened silico-sodo-calcic monolithic substrate having a suitable stress level, notably of at least 120 MPa for a thickness of the order of 6 mm.
15. Glazed element (1) according to one of claims 1 to 14, characterized in that the flame-arrester pane comprises at least one substrate of glass having a low coefficient of thermal expansion and/or based upon boro-silicate glass.
16. Glazed element (1) according to one of claims 1 to 15, characterized in that the flame-arrester pane comprises a plurality of monolithic glass substrates associated, notably, by means of intermediate material or materials and/or by means of intermediate layer or layers of gas.
17. Use of the glazed element (1) according to one of the preceding claims as fire-arrester pane having a fire-resistance according to the Standards ISO 3009 and 834 of at least 30 minutes.
18. Use of a fibrous material (6) having a high porosity and high modulus of elasticity, the properties and/or the structure of which are maintained unchanged at high temperature, for holding at least one edge of the periphery of a flame-arrester pane (1) in the rebate of a frame by interposition between glass and rebate, said material being intended for penetrating into the pane when the latter approaches or reaches its softening temperature.
19. Use according to claim 18, characterized in that the fibrous material (6) has a porosity of at least 50%.
20. Use according to claim 18 or 19, characterized in that the fibres of this fibrous material (6) have a modulus of elasticity of at least 150,000 MPa.
21. Use according to one of claims 18 to 20, characterized in that the fibrous material (6) is a material that conducts heat and electricity.
22. Use according to one of claims 18 to 21, characterized in that the fibrous material (6) is essentially metallic, notably based upon stainless steel or copper.
23. Use according to one of claims 18 to 22, characterized in that the fibrous material (6) is constituted of fibres assembled in the form of braids and then wrapped with a wire of a similar nature, or of threads assembled in the form of tubular knitting.
24. Use according to one of claims 22 or 23, characterized in that the fibres of the fibrous material (6) are in the form of shavings obtained from continuous, thick metal wires.

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