GB2245301A

GB2245301A - Frameworks for fire-resistant screens and doors

Info

Publication number: GB2245301A
Application number: GB9115037A
Authority: GB
Inventors: Jeffrey Robert Skeggs; Peter Jackman
Original assignee: BRIGGS AMASCO Ltd
Current assignee: BRIGGS AMASCO Ltd
Priority date: 1987-11-20
Filing date: 1991-07-05
Publication date: 1992-01-02
Anticipated expiration: 2008-11-21
Also published as: GB2212546A; GB2245301B; GB8827137D0; GB9115037D0; GB2212546B

Abstract

Glazing panel 20 is supported on rectangular-section steel tubes forming a framework by stop beads 126, 134 fixed to the tube. In other embodiments, one stop bead may be fixed to the tube and the second fixed to a part of the first which extends under the edge of the glazing panel 20. Intumescent or other seals may lie between the stop beads and the glazing panel. <IMAGE>

Description

ERAYEWCRKS FOR FIRE-RESISINNT SCREENS AND DOORS The invention relates to improvements in frame-works systems for glazed fire-resistant screens or doors. It also relates to an assembly for holding panels in mounting channels.

A known framework for a fire-resistant glazing system is made up from specially formed steel tubes of rectangular cross-section. One of the walls of the section extends out beyond the adjacent walls to form a lip. A frame for a door or screen is constructed from such tubes so that the lips and adjacent walls form a rebate for receiving the glazing panel.

The edge of the glazing panel, sandwiched between two layers of intumescent material, is held between the lip and a stop bead formed by an inverted U-shaped steel beading channel.

The steel channel is fixed in position by clipping on to studs screwed in to the wall of the steel tube. The steel tube must be of sufficiently heavy guage to provide the required structural strength to the framework.

A disadvantage of such a system is that the steel tube is a non-standard design and therefore has to be specially made.

This makes the system expensive.

An aim of one aspect of the present invention is to provide a system which can use standard stock steel tubing for the framework.

According to the present invention there is provided a framework for a glazed fire-resistant door or screen, the framework being constructed from steel tube of recnguiaw cross-section, the edges of a glazing panel being held by first and second stop beading on either side of the panel, the stop beading being secured to the steel tube by fixing means.

With this construction, the steel tube can be of standard size and shape.

The stop beading may comprise inverted beading channels of U-shaped cross-section which clip on to fixings on the steel tube. The fixings may comprise for each beading, a row of studs with heads which taper towards the steel tube so that they can be gripped by the edges of the beading channel. The beading channel may have its edges turned in to provide lips for gripping the studs.

In another constuction, the first beading has a sideways extension which carries fixings for securing the second beading. The first beading is attached to the steel tube, for example with screws, before the glazing panel is inserted and then the second beading is secured to the fixings carried by the sideways extension of the first beading. Other means for securing the first beading may be used such as popriveting or spot welding. The first beading may be of inverted U-shaped channel with the sideways extension extending from an edge of the channel. The fixing for the second beading may comprise an inverted channel-shaped rib on the sideways extension, of smaller dimensions than the first beading.The rib may taper in width towards the steel tube to provide an undercut for better gripping by the second beading. The second beading may comprise an inverted U-shaped channel with its edges turned in to form lips for gripping of the fixings.

In another construction the first beading is formed by a right-angle section secured to the steel tube.

A feature of the preferred embodiments is that the fixings for the beading are concealed by beading and/or the glazing panel in the finished assembly.

Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Fig. 1 shows an example of a fire-resistant screen which may be constructed using a framework in accordance with the present invention; Fig. 2 shows, on an enlarged scale, a cross-section through a frame member which may form part of the framework of Fig. 1; Fig. 3 shows, on an enlarged scale, a cross-section through an alternative construction of frame mEmber; Fig. 4 shows, on an enlarged scale, a cross-section through a second alternative construction of frame member; Fig. 5 shows a third alternative construction of frame member; Figure 6 shows a glazing channel fire seal for use with fire resistant glazing systems mounted in a frame member; Figure 7 shows an alternative oonstruction of frame member;; Figure 8 shows a second alternative construction of frame member; and Figure 9 shows a third alternative construction of frame mEmber.

Referring to Fig. 1, this shows a typical glazed fire-resistant screen which may be constructed in accordance with the invention. The screen 10 is constructed of vertical and horizontal frame members 11 and 12 held together by spigot and socket joints 13. The screen is held in the opening 14 by means of U-shaped channels 15 secured by screws to the edges of the opening before the screen is installed. The sides of the U-shaped channels 15 overlap the frame members 11 and 12 at the periphery of the screen to locate the screen in position. A door opening 16 is formed in the screen and two pivoted hinged doors 17 are mounted in the door opening. The doors are made up of vertical and horizontal frame members 18 and 19.The openings within the framework formed by the frame mEmbers 11 and 12 and 18 and 19 are glazed with fire-resistant glazing panels 20, for example of Pyran, Pyrostop, Pyrobel, Pyroswiss or of Georgian Wire Polished Plate. All the frame members are made of steel tubing to give the structure the necessary strength and integrity in the event of a fire.

Fig. 2 shows a construction for the frame members 11, 12 of Fig. 1. The frame members comprise steel tube 21 of rectangular cross-section. In the present example square cross-section is used. Fig. 2 shows how the frame member is inserted in the channel 15 at the edge of the opening with rock wool 22 inserted between the channel and the frame member.

A first row of studs 23 is screwed into the wall 29 of the steel tube 21. The studs 23 are spaced evenly along the length of the tube. The heads 24 of the studs taper conically towards the tube so as to form an undercut 25. A first beading 26 is formed from U-shaped steel channel. The edges of the channel are turned inwardly to form inwardly projecting lips 27. The beading is pushed onto the studs 23, the resistance of the steel allowing the walls of the channel to flex so that the lips 27 can pass over the heads 24 and grip the studs at the undercut 25. Thus the first beading is securely held in position.

Beading is fixed to the frame members around all the openings in the framework in a similar manner.

The edge of a glazing panel 20 is sandwiched between two layers 30 and 31 of intumescent material and placed up against the beading 26. A suitable intumescent material consists of a core of hydrated sodium silicate reinforced with glass fibres, the core being protected by a coating of eppoxide resin. A non-combustible block 32 may be placed between the outside edge of the glazing panel and the steel tube 21.

A second row of studs 33, identical to the first, is then inserted in the same wall 29 on the opposite side of the glazing panel from the first row and a second beading 34, identical to the first, is clipped onto the studs 33 to hold the glazing panel in position.

Before the intumescent material has been activated, the glazing 20 is held in position in the channel 11 by the unexpanded intumescent strips 30 and 31 packed either side of the edge 77 of the glazing 20.

When the assembly is subjected to a sufficiently high temperature, as in the case of a fire burning sufficiently close to the glazing system, the heat is conducted through the steel itountings to the intumescent strips 30 and 31. The intumescent strips 30 and 31 expand thereby increasing the gripping pressure exerted on the faces of the edge of the glazing 20, thus tending to hold it more firmly.

Fig. 3 shows an alternative construction for the frame members of Fig. 1.

A first sheet steel beading 36 is formed by an inverted U-shaped channel which has a sideways extension 37 extending from one edge of the channel. Holes 38 are provided in the extension 37 at intervals along its length and the beading 36 is secured to the wall 29 by self-tapping screws 39 which pass through the holes 38 into holes in the wall 29. Other methods of fixing the beading to the wall 29 may be used, for example popflveting or spot welding.

A rib 40 is formed along the edge of the extension 37 remote from the beading 36. The rib is formed as an inverted channel of smaller dimensions then the beading 36 and tapers in width towards the steel tube 21 so as to form undercuts 41.

As in figure 2, the edge of the glazing panel 20 is sandwiched between two layers 30 and 31 of intumescent material. A non-osmbustible block 32 may be placed bwtween the outside edge of the glazing panel the upper face of the sideways extension 37.

A rubber close cell 58 is placed between the beading 36 and the intumescent material 30 as a packing material. Different thicknesses of glazing can be accommodated in a single size of frame member by using suitable sizes of the rubber close cell 58.

A second sheet steel beading 51 is pushed onto the rib 40 to hold the glazing panel 20 in position. The beading 51 is similar to the beading 34 of Fig.2 except that the wall 52 of the channel closest to the glazing panel slopes inwardly from the web portion towards the free end to allow the free end of the beading to expand sufficiently to be fitted over the rib 40.

When the beading 51 is pushed on the rib 40, the inturned lips 27 grip the undercuts 41 on the rib to hold the beading in position.

Fig. 4 shows a second alternative constuction of frame member identical to the construction of Fig. 3 except that the intumescent material is replaced by compressible gaskets 70, and the glazing panel 20 is held more directly by the beadings 36 and 51.

Fig. 5 shows a third alternative construction of frame member. A steel right-angled L shape section 60 is secured to the wall 29 of the steel tube 21 by means of screws (not shown) or by means of pop rivets. The edge of a glazing panel 20 sandwiched between two strips of close cell rubber, is placed in the rebate formed by the angle of the section 60. A non-ccmblstible block 32 may be placed around the edge of the glazing panel. The glazing panel is held in position by a beading 6i similar to the beading 51 of Fig. 3 but .mich is clipped on to a row of studs 62 similar to the studs 33 of Fig. 2.

The framework can be constructed from steel tubes that is of a standard size manufactured by steel tubing marmalfacturers.

The beading channels may be formed, for example, from galvanised sheet steel.

Referring to Figure 6, a sheet of fire resistant glazing 20, for example of Pyran, Pyrostop, Pyrobel, Pyroswiss or of Georgian Wire Polished Plate, has its edge 77 mounted between two strips of intumescent material 30 and 31 contained in a steel channel 50 of generally rectangular cross section. A suitable intumescent material consists of a core of hydrated sodium silicate reinforced with glass fibres, the core being protected by a coating of expoxide resin. The channel 50 is mounted on a profiled hollow tubular steel frame 71. The channel 50 sits between, and is held in position by, a flange 72 formed on the frame 71 and a steel bead 100 secured to the frame 71 by a screw 73. As in the previous embodiments, steel is used as it has a high melting temperature compared with other materials, such as aluminium, which are often used to mount glazing panels.The channel 50 has the front edges of its side walls turned in to form lips 74 and 75 which form a constriction in the open side of the channel 50. The glazing 20 fits between the lips 74 and 75 leaving a clearance 76.

Before the intumescent material has been activated, the glazing 20 is held in position in the channel 50 by the unexpanded intumescent strips 30 and 31 packed either side of the edge 77 of the glazing 20. The clearance 76 prevents the lips 74 and 75 of the channel 50 from damaging and hence weakening the glazing 20 at the point where it enters the channel 50.

When the assembly is subjected to a sufficiently high temperature, as in the case of a fire burning sufficiently close to the glazing system, the heat is conducted through the steel mountings to the intumescent strips 30 and 31. The intumescent strips 30 and 31 expand inside the channel 50 thereby increasing the gripping pressure exerted on the faces of the edge of the glazing 20, thus tending to hold it more firmly in the channel. The flange 72 and the bead 100 buttress the side walls of the channel preventing them from distorting outwardly under the pressure of the expanding intumescent material. The turned-in lips 74 and 75 of the channel 50 resist extrusion of the expanding intumescent material from the channel 50. There may be some leakage of expanding intumescent material through the small clearance 76 at the entrance to the channel 50, but this leakage will be small. Thus, the expanding intumescent material reins substantially within the channel 50, and the gripping pressure exerted on the edge 77 of the glazing 20 is greater than for a similar system with no constriction where the intumescent material can extrude freely from the channel.

Referring to figure 7, a frame member comprise steel tube 121 of rectangular cross-section. In the present example square cross-section is used.

A first row of studs 123 is screwed into the wall 129 of the steel tube 121. The studs 123 are spaced evenly along the length of the tube. The heads 124 of the studs toper conically towards the tube so as to form an undercut 125. A first beading 126 is formed from U-shaped steel channel. The edges of the channel are turned inwardly to form inwardly projecting lips 127. The beading is pushed onto the studs 123, the resistance of the steel allowing the walls of the channel to flex so that the lips 127 can pass over the heads 124 and grip the studs at the undercut 125. Thus the first beading is securely held in position.

The edge of a glazing panel 20 is sandwiched between two layers 30 and 31 of intumescent material.

A channel 150 of steel surrounds the edges of the glazing panel 120 and the intumescent material. The channel 150 has side walls 210 and 211 which diverge away from the base 213 of the channel. The edges of the channel 150 are turned inwardly towards the glazing panel to form lips 176. The lips 176 are inclined at an angle of approximately 450 to the base of the channel. The lips 176 grip the sides of the glazing 120 to hold the glazing in the channel normally. The lips 176 also restrict the flow of intumescent material out of the channel 150 in the event of a fire. A non-combustible block 132 may be placed bwtween the edge of the glazing and the base of the channel.

The glazing and the channel are placed up against the first heading 126. A second row of studs 133, identical to the first, is then inserted in the same wall 129 on the opposite side of the glazing channel to the first row.

A second beading 134 is clipped onto the studs 133 to hold the channel in position on the frame. As can be seen in figure 9, the tapered channel wall leaves room for the mouth of the second beading, to expand to fit over the heads of the studs 133 to enable the beading to be clipped in place.

Figure 8 shows an arrangement similar to that of figure 7, but with the channel 50 having side walls which are approximately parallel to one another, and lips which are approximately parallel with the base of che channel. In this figure, the lips do not grip the glazing 20; the glazing is held by the layers of intumescent material 30 and 31.

Referring to figure 9, a first sheet steel beading 36 is formed by an inverted U-shaped channel which has a sideways extension 37 extending from one edge of the channel. Holes 38 are provided in the extension 37 at intervals along its length and the beading 36 is secured to the wall 29 by self-tapping screws 39 which pass through the holes 38 into holes in the wall 29. Other methods of fixing the beading to the wall 29 may be used, for example popflveting or spot welding.

A rib 40 is formed along the edge of the extension 37 remote from the beading 36. The rib is formed as an inverted channel of smaller dimensions that the beading 36 and tapers in width towards the steel tube 21 so as to form undercuts 41.

A channel 50 of steel surrounds the edges of the glazing panel 20. Layers of intumescent material 30 and 31 are placed between the walls of the channel and the glazing panel 20 and a block of non-ccm#bustible material 32 is placed between the edge of the glazing panel and the web of the channel 50. The edges of the channel are turned inwardly towards the glazing panel to restrict the flow of intu:nscent material out of the channel 50, in the event of a fire.

The glazing panel 20 with the surrounding channel 50 is placed in the rebate formed between the beading 36 and the extension 37. A second sheet steel beading 51 is then pushed onto the rib 40 to hold the glazing panel 20 and channel 50 assembly in position. The beading 51 is then pushed onto the rib 40 to hold the glazing panel 20 and channel 50 assembly in position.

The beading 51 is similar to the beading 80 of Fig. 7 except that the wall of the channel closest to the glazing panel slopes inwardly from the web portion towards the free end to allow the free end of the beading to expand sufficiently to be fitted over the rib 40.

The glazing 20 can be mounted in suitable channels 50 which extend around all the edges of the glazing. However, in the event of a fire, if the glazing softens and begins to sag in its frame, it is usually the top edge of the glazing which is the first to tend to fall out of its mounting channel. Thus in certain applications providing limited fire protection, it may be sufficient to mount the glazing with a channel 50 fitting only to the top edge of the glazing.

Although the channel has been described for use to mount sheets of glazing, it will be appreciated that it could be used for mounting other types of panels.

All the frame members 11,12,18 and 19 of Fig. 1 may be constructed in the manner of Figs. 1 to 5, 7, or 9. Where glazing panels are on both sides of the steel tube 21, beading for holding the glazing panel will be provided on two opposite walls of the steel tube.

Claims

CTSDIS:

1. A framework for a glazed fire-resistant door or screen, the framework being constructed from steel tube of rectangular cross-section, the edges of a glazing panel being held by first and second stop beading on either side of the panel, the stopbeading being secured to the steel tube by fixing means.

2. A framework according to claim 1, wherein the fixing means are concealed in the asembled condition.

3. A framework according to claims 1 or 2, wherein the stop beading comprises inverted channels of U-shaped cross section.

4. A framework according to claim 3, wherein the fixing means comprise studs located in rows on the steel tube, the stop beading being clipped over the studs.

5. A framework according to claim 4, wherein the channel has its edges turned in to provide lips for gripping the studs.

6. A framework according to claim 3, 4 or 5, wherein the studs have heads which taper towards the steel tube, such that the sides of the channel can grip the studs.

7. A framework according to claims 1, 2 or 3, wherein the first beading has a sideways extension which carries second fixing means for securing the second beading to the first beading.

8. A framework according to claim 7, wherein the first beading is attached to the tube by means of screws.

9. A framework according to claim 7 or 8, wherein the second beading is clipped on the second fixing means.

10. A framework according to claim 9, wherein the second fixing means comprise an inverted channel-shaped rib on the sideways extension.

11. A frame work according to claim 10, wherein the second beading comprises an inverted U-shaped channel with its edges turned in to form lips for gripping the rib.

12. A framework according to claim 11, wherein the rib tapers in width toward the steel tube, such that the channel can grip the rib.

13. A framework according to any of claims 1 to 12, constructed by first securing the first beading to the steel tube, locating the edge of the glazing between the first beading and the position for the second beading, and securing the second beading in position.

14. A framework substantially as hereinbefore descirbed, with reference to figures 1 to 5, 7 and 9 of the accompanying drawings.