GB2067639A

GB2067639A - Fire-resistant screens

Info

Publication number: GB2067639A
Application number: GB8100371A
Authority: GB
Original assignee: Saint Gobain Vitrage SA
Current assignee: Saint Gobain Vitrage SA
Priority date: 1980-01-10
Filing date: 1981-01-07
Publication date: 1981-07-30
Also published as: ES265099U; DE3100040A1; IT1134993B; BE887031A; GB2067639B; IT8119078A0; FR2473592A1; FR2473592B1; ES265099Y

Abstract

A metal framework for a fire- resistant glazed screen comprises uprights 1 and traverse members 2 joined by cross-pieces 3, 4 parallel thereto to form frames in which panes may be mounted. The cross-pieces are connected to each other and to the uprights and traverse members by enclosure, with play, of parts of these elements in openings in the other elements. The cross-pieces can then expand freely on heating without imposing stresses on the panes. <IMAGE>

Description

SPECIFICATION Fire-resistant screens The invention relates to fire-resistant glazed screens formed of a plurality of panes. It concerns more particularly a metal chassis allowing such partitions to withstand expansions produced under the effect of heat without giving deformations likely to cause destruction of the panes with which they are equipped or preventing them satisfying stadards or air-tightness and the absence of overheating required for the panes.

It has already been suggested in the art to provide panes which have a high resistance to fire and which, consequently, efficiently obstruct spreading of fires. Such panes are for example, described in French Patent Application 7609227 published under No. 2346548. They comprise between two parailel glass sheets held spaced one from the other, a gel comprising between 65 and 95% by weight of liquid having a high heat of evaporation, and between 1 and 20% by weight of a substance compatible with the gel and capable of forming an insulating foam under the effect of thermal radiation.The gel may be for example, based on a derivative of acrylic acid, the liquid having a high heat of evaporaticn may be water and the substance capable of producing a foam is a soluble salt chosen among the aluminates, silicates, stannates, plu mbates, albums, borates, phosphates and their alkali metal or ammonium salts.

Such panes subjected to fire trials according to German Standard DIN 4102 give entire satisfaction and act as fire resistant for durations which may reach several hours. In fact, if the sheet of glass exposed to the fire breaks rapidly, the layer of gel then forms a thermal screen which opposes spread of the heat in the direction of the second glass sheet.

It is thus in principle possible to make efficient fire-resistant screens with such panes, but the deformations to which the metal chassis are subjected under the effect of heat impose severe mechanical stresses on the panes and generally cause premature rupture of the latter thus preventing them resisting spread of flames.

The present invention is intended to avoid this disadvantage by providing fire-resistant screens for such panes in which the metal chassis may expand freely under the effect of heat without imposing deformation or abnormal stresses on the panes.

According to one aspect of the invention there is provided a metal chassis for a fire-resistant glazed screen comprising elements consisting of uprights, traverse members and cross-pieces parallel to said uprights and said traverse members, the elements being connected to form frames for glazing panes, said cross-pieces being connected to each other and to said traverse members and said uprights by enclosure of a part of one element in an opening provided in the element to which it is connected, sufficient longitudinal play between said part and said opening being provided to allow the free expansion of the chassis under the effect of heat in the most severe conditions of fire tests which have to be withstood by said panes tested alone.

Preferably, the available longitudinal play will be at least 5 mm per linear metre of the element.

The vertical cross-pieces may for example be provided with end projections enclosed in a mounting attached to said traverse members or in one or more cut-outs provided in said traverse members.

Inversely, the vertical cross-pieces may have hollow ends in which will be enclosed projections carried by the traverse members.

In analogous fashion the horizontal crosspieces may comprise end projections engaged in mountings attached to the vertical cross-pieces and/or on the vertical uprights, or further engaged in cut-outs provided in the vertical cross-pieces and/or in the vertical uprights.

The horizontal cross-pieces may also comprise hollow ends in which will be engaged projecting members carried laterally by said vertical crosspieces and said vertical uprights. In one embodiment the ends of the horizontal crosspieces will I have a U section covering projecting members of the vertical cross-pieces and/or the uprights.

On such a chassis, the fire-resistant multiple panes may advantageously be centred by fireproof blocks arranged along the lower traverse member and possibly on the uprights.

Airtightness to hot gases, in the case of fire, can be assured by adhering, preferably on the chassis, at right angles to the sections of the panes, strips of a tissue or a mat of fibres of glass impregnated with sodium silicate capable of expanding under the effect of heat.

Finally, coverings will generally be fixed on the chassis to cover the edges of the panes.

The accompanying drawings will illustrate embodiments of the invention by way of example.

In the drawings: Figure 1 is a schematic view in elevation of a glazed screen, Figures 2, 3 and 4 are details on a greater scale of the parts marked II, Ill, and IV in Figure 1.

Figure 5 is an exploded view of the chassis of the screen of Figure 1, Figure 6 illustrates schematically a variant of the assembly of the traverse members and the intermediate members.

The fireproof screen shown in Figure 1 comprises a metal chassis formed of uprights 1, traverse members 2 and vertical cross-pieces 3 and horizontal cross-pieces 4 defining frames for holding fire resistant multiple panes 5, six in number in the case shown in the drawings. The uprights 1 and the traverse members 2 are normally sealed in the masonry of a building.

The vertical cross-pieces 3 comprise longitudinal recesses 3a in which are engaged projections 6 carried by the traverse members 2 as shown in Figures 2 and 6. These projections are simply enclosed with the possibility of longitudinal play in the recesses 3a, a play which allows the cross-pieces to expand freely in the longitudinal direction when they are exposed to heat released by fire.

In a similar manner the horizontal cross-pieces 4 comprise ends 4a having a U section which simply cover with longitudinal play projections 7 carried by the vertical cross-pieces 3 (Figures 4 and 6). The horizontal cross-pieces may expand freely, as is the case with the vertical cross-pieces under the effect of heat, without imposing stresses on the panes.

As has been indicated above, the degree of freedom of the cross-pieces will be at least 5 mm per linear metre.

One of the vertical cross-pieces is formed of two half-profile members 9 of which the ends 9a comprise recesses in which there may be engaged projections 10. The advantage of such a construction is that it is possible to assemble glazed modules of standard dimensions which may be fixed inside a frame formed by the vertical uprights and horizontal traverse members and be dismounted easily. Holf-profile member 1' of the same type as the half-profile members 9, in association with profile members 1 having a section of omega shape sealed in the masonry, may be used to form the vertical uprights of the frame, projections 6' carried by the traverse members 2 being enclosed with play in the recesses 1 a provided at the ends of the half profile members 1'.

The mounting of the cross-pieces is carried out by engaging the projection 6 of the traverse members 2 in the recesses 3a in the ends of the vertical cross-pieces 3, then covering the projections 7 by means of the ends 4a of the horizontal cross-pieces 4. The cross-pieces are then fixed in position by means of screws engaged in openings such as 11 in the different elements and associated nuts, these screws and nuts being of course removed after the final mounting in place of the fire-resistant panes to allow the crosspieces to expand freely.

In order to prevent lateral displacement of the vertical cross-pieces 3, their ends may be locked outside by blocks secured on the lower traverse member on the side opposite the opening 3a.

A vertical cross-piece according to another embodiment is shown in Figure 6. In this embodiment the cross-piece 13 comprises two end projections 1 3a which are engaged in a cutout 14 in the traverse members 2 where they may expand freely. It is possible to provide in the traverse member 2 two distinct cut-outs, one for each of the projections 1 3a. In this case there will advantageously be adopted for the horizontal traverse members a structure similar to that of the vertical uprights, that is to say a profile member of omega section sealed in the masonry and associated with a half-profile member in which will be provided the cut-outs.

In a manner kno n as such, the panes may be positioned in their framers, for example by two blocks arranged below their lower sections and one block on each of their vertical sections. These blocks should be of an incombustible material such as asbestos or a mixture of cement and asbestos, whereas the airtightness to hot gas of the pane as mounted may be ensured by sticking onto the frame of the pane or on the sections of the pane on their four sides strips of a tissue or a mat of glass or rock fibres impregnated with sodium silicate which expands on heating. Strips of such material are, for example, sold under the name DELMO-FEU (registered trade mark).

Finally, frames formed of profile members having a very flat U cross-section inside which is arranged a plate of a thermal insulator of the fibrocement type (for example, the insulator sold commercially under the name of PROMABEST Y) are fixed by screws on the element of the chassis, with covering of the edges of the panes.

The screen described above, when subjected to a fire test according to the standard DIN 4102 have perfectly resisted flames up to the point where the multiple panes break under the effect of fire and not under the effect of mechanical stresses resulting from deformations of the chassis.

Claims

1. A metal chassis for a fire-resistant glazed screen comprising elements consisting of uprights, traverse members and cross-pieces paraliel to said uprights and said traverse members the elements being connected to form frames for glazing panes, said cross-pieces being connected to each other and to said traverse members and said uprights by enclosure of a part of one element in an opening provided in the element to which it is connected, sufficient longitudinal play between said part and said opening being provided to allow the free expansion of the chassis under the effect of heat in the most severe conditions of fire tests which have to be withstood by said panes tested alone.

2. Chassis according to Claim 1, in which said longitudinal play is at least 5 mm per linear metre of the cross-pieces.

3. Chassis according to one of Claims 1 and 2, in which the vertical cross-piece comprises end projections enclosed in a mouting supported on said traverse members or in one or more cut-outs provided in said traverse members.

4. Chassis according to one of Claims 1 and 2, in which the vertical cross-piece comprises hollow ends, in which are enclosed projecting members carried by the traverse members.

5. Chassis according to any one of Claims 1 to 4, in which the horizontal cross-piece comprises end projections engaged in mountings supported on the vertical cross-piece and/or the vertical uprights or in cut-outs provided in said vertical cross-piece and/or vertical uprights.

6. Chassis according to one of Claims 1 to 4, in which the horizontal cross-piece comprises hollow ends in which are engaged projecting members carried laterally by the vertical cross-piece and the vertical uprights.

7. Chassis according to Claim 6, in which the ends of the horizontal cross-piece have a U shaped section and cover said projecting members.

8. Chassis for a fire-resistant glazed screen, substantially as hereinbefore described with reference to the accompanying drawings.

9. Fire-resistant glazed screen in which fireresistant panes are carried by a chassis according to any one of Claims 1 to 8.

1 0. Glazed screen according to Claim 9, in which fire-resistant panes are centred by incombustible blocks arranged along the lower traverse member and optionaly along the uprights.

11. Glazed screen according to one of Claims 9 and 10, in which strips of tissue or mat of glass or rock fibre impregnated with sodium silicate and capable of expanding under the effect of heat are adhered to the chassis at right angles to the sections of the panes.

12. Glazed screen according to one of Claims 9 to 11, in which covering is fixed on the chassis to cover the edges of the panes.

13. Glazed screen according to Claim 12, in which said frames are formed of profile members of very flat U section in which is arranged a plate of thermal insulator.

14. Fire-resistant glazed screen, substantially as hereinbefore described with reference to the accompanying drawings.