GB2224767A

GB2224767A - Glazed fire-resistant screen

Info

Publication number: GB2224767A
Application number: GB8823450A
Authority: GB
Inventors: Robert Henry Barrs; Jeffrey Robert Skeggs
Original assignee: BRIGGS AMASCO Ltd
Current assignee: BRIGGS AMASCO Ltd
Priority date: 1988-10-06
Filing date: 1988-10-06
Publication date: 1990-05-16
Anticipated expiration: 2008-10-06
Also published as: GB2224767B; GB8823450D0

Abstract

A glazed fire-resistant screen includes a glazing panel (13) supported at its edge by a frame member (11) of rectangular steel tubing. Two strips (12) of rigid self-supporting non-combustable heat-insulating material are secured on opposite sides of the steel tubing, the edges of the strip (12) overlapping the edge of the glazing (13). Protective metal cladding (20) is secured to cover the strips (12) by means of clips (17), and sealing gaskets (22) are placed between the edges of the cladding (20) and the glazing (13). In the event of a fire on one side of the screen, the strips (12) of insulating material resists the conduction of heat through the frame, so that the screen forms a heat-resistant barrier. The edge of the glazing panel is also insulated from heat, to reduce the effect of sagging and drawing of the glazing at its edge, and therefore keep the screen intact for sometime. <IMAGE>

Description

GLAZED FIRE RESISTANT SCREENS The present invention relates to glazed fire-resistant screens as are used in buildings to comply with building regulations and provide a barrier to hinder or delay the passage of flames and hot gases in the event of a fire.

For certain purposes it is necessary to provide a screen that not only will remain intact in the event of a fire, but also will prevent the transmission of heat from one side of the screen to the other.

In a glazed screen, the structural strength is usually provided by a framework of steel tubing. Because steel is a good conductor of heat, thermal insulation is required if the screen is to prevent the transission of heat. In a known construction, each structural member of the framework comprises two rectangular-section steel tubes with a layer of thermally insulating material sandwiched between them. The glazing panels are held in place on the steel tubing by steel beading.

A disadvantage of the known construction is that because two steel tubes are used for each frame member, the structure is heavy, bulky and expensive. Furthermore, as the steel is at the outside of the structure, it limits the decorative finishes that can be applied unless a decorative cladding material is applied over it.

According to the present invention, there is provided a glazed fire-resistant screen in which the frame members comprise rectangular steel tubing and two strips of rigid self-supporting non-combustible heat insulating material secured on opposite sides of the steel tubing, the edges of the strips overlapping the edge of the glazing panel. The insulating material locates the glazing panel. A layer of compressible material may be placed between the glazing panel and each strip of insulating material. The insulating material strips may be covered with a metal cladding, for example, of aluminium or steel extrusion, to provide a decorative finish and to protect the insulating material during normal use. Rubber sealing gaskets may be placed between the cladding and the glazing panel.

The screen, according to the present invention, can be made of lighter construction than the known design because it has only one steel tube for each frame member. Because the insulating material overlaps the edge of glazing panel, it protects the edge from external heat, keeping it cool in the event of a fire and thus helping to prevent the glazing panel sagging and falling out of the screen.

Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, of which:- Fig. 1 shows a cross section through a first frame member in accordance with the invention; Fig. 2 shows a cross section through a second frame member in accordance with the invention; Fig. 3 shows a cross section through a third frame member in accordance with the invention; Fig. 4 shows a cross section through a fourth frame member in accordance with the invention.

Fig. 5 shows a fragmentary cross-section through fifth frame member with a modified form of plastics clip and gasket, in accordance with the invention.

Referring to Fig. 1, this shows a cross-section through a part of a glazed fire-resistant screen in accordance with the invention. The framework of the screen is made up of rectangular section steel tubing 11. Strips 12 of a rigid self-supporting non-combustible heat insulating material are secured to either side of the steel tubing by screws (not shown) which pass through the strips into walls of the steel tubing 11. The strips 12 may be of any suitable material, for example, calcium silicate monolithic board.

The edges of the strips 12 overlap the edges of fire-resistant glazing panels 13 and 14. A layer of conpressible material 15 is placed between each glazing panel 13,14 and each strip 12 so that the strips firmly grip the glazing panels. Spacers 16 of non-combustible material may be located between the edge of each glazing panel and the steel tubing 11.

Plastic clips 17 are fitted at intervals along the strips 12.

The clips are U-shaped and have tabs 18 on the insides of their outer ends which grip into the sides of the strips. On the outsides of their limbs the clips are formed with barbs 19.

A cladding 20 of extruded aluminium or steel is fitted over each strip 12. The cladding is of channel-shaped section and has ridges 21 formed on its inside which co-operate with the barbs 19 on the plastic clips to hold the cladding in position. The cladding provides a decorative finish to the structure and protects the strips 12 during normal use.

Rubber sealing gaskets 22 are fitted over the edges of the cladding before the cladding is pushed onto the strips 12.

The rubber gaskets form a seal against the surface of the glazing panels. The cladding and gaskets serve further to support the glazing panel during normal use.

In the event of a fire on one side of the screen, the strips 12 of insulating material together with the glazing panels 13 and 14 and the intumescent material 15 form a continuous heat insulating barrier between opposite sides of the screen. The strips protect the steel tubing and the edge of the glazing panels form the heat ensuring that the screen remains intact for some time.

If the temperature of the fire is sufficiently high, the aluminium cladding 20 and the rubber gaskets 22 may be destroyed. The strips 12 will, however, remain intact and continue to grip the glazing panels and protect the glazing panels and the steel tubing from the heat.

Fig. 2 shows a modification of the frame member of Fig. 1, as would be used at the perimeter of the screen for securing the screen to the edge of the opening in which the screen is located. The glazing panel 14 is omitted and instead, a strip of steel 30 is secured at right angles to the wall of the steel tubing opposite the glazing panel 13, for example, by welding.

An angle section 31 is secured to the wall 32 of the opening by screws 33. Packing material 34 is placed between the wall and the section 31. The tubing 11 is secured to the section 31 and thus the wall 32 by self tapping screws 35 which pass through holes in the angle section 31 and steel strip 30. In other respects the frame member of Fig. 2 is the same as that of Fig.1.

Fig. 3 shows a section through part of an alternative design of screen according to the invention. In many respects the design of Fig. 3 is similar to that of Fig. 1. Strips 12 of rigid self-supporting non-combustible heat insulating material as screw fitted to the steel tubing 11. Glazing panels 13 and 14 are fitted between the strips 12, the strips overlapping the edges of the glazing panels. Spacer blocks 16 of non-combustible material are placed between the edges of the glazing panels 13 and 14 and the steel tubing 11. However, in this embodiment the cladding 28 is formed by pressing from aluminium or steel sheet and the cladding is held in position by screws (not shown) at the ends of the cladding 28 instead of by the plastics clips 17.

In this embodiment the compressible material has been omitted and the glazing panels are held firmly in position by rubber gaskets 51 which are pushed into position as the final step of assmebly. The gaskets 51 have ribbed tongues 52 which enter between the edge of the glazing panel 13, 14 and the strip 12 of insulating material. A flange 53 on the gasket 51 overlaps the edge of the cladding 28 to secure the cladding further.

As with the embodiments of Fig. 1 and 2, the strips 12 of Fig.

3 protect the edge of the glazing panels and the steel tubing from heat in the event of fire, and together with the glazing panels provide a thermally insulating barrier between opposite sides of the screen.

Fig. 4 shows a modification of the arrangement Fig. 3 as would be used at the perimeter of the screen for securing the screen to the edge of an opening in which the screen is located. In this arrangement the glazing panel 14 is omitted. A U-shaped steel channel 60 is secured to the wall 61 of the opening by screws (not shown) which pass through the web portion of the channel into the wall. Other methods of fixing the channel to the wall may be used. The channel 60 is arranged with its web portion furthest from the wall. The steel tubing 11 is secured to the channel 60 by self tapping screws (not shown) which pass through the larger walls of the tubing into the web of the channel 60. Packing material 63 may be inserted between the steel tubing and the web portion of the channel 60.

The strips 12 may have a rebate 65 on their inside to accommodate the steel tubing 11. Sealing material 66 may be placed between the cladding 28 and the wall 61.

In other respects the arrangement of Fig. 4 may be the same as that of Fig. 3.

Fig.5 shows a cross-section through further modified arrangement in accordance with the invention. In the embodiment of Fig.5 the plastic clip 171 has inwardly projecting tabs 70 at its free ends which are engaged around the inner edges of the strips 12 to hold the clip 171 in position on the strip, the clips flexing to allow the tabs to pass around the sides of the strips when the clips are being installed. A modified form of gasket 71 is used which has ribs 72 inclined towards the outside of the assembly so as to resist removal of the gasket from the space between the glazing panel on the one hand and the plastic clip 171 and strip 12 on the other.

Claims

1. A glazed fire-resistant screen including a glazing panel supported at its edge by a frame member, the frame member comprising rectangular steel tubing and two strips of rigid self-supporting non-combustible heat-insulating material secured on opposite sides of the steel tubing, the edges of the strips overlapping the edge of the glazing panel.

2. A glazed fire-resistant screen according to claim 1, wherein the strips of insulating material are each covered with a metal cladding.

3. A glazed fire-resistant screen according to claim 2, wherein the cladding is secured to the insulating material by screws.

4. A glazed fire-resistant screen according to claim 2, wherein the cladding is secured to the insulating material by means of clips fitting between the cladding and the insulating material.

5. A glazed fire-resistant screen according to claim 4, wherein the clips are generally U-shaped, having opposed inwardly-projecting tabs at their ends for securing the clip to the insulating material, and outwardly projecting barb-like projecticns for gripping the inner face of the cladding.

6. A glazed fire-resistant screen according to claim 2, 3 or 4, wherein the cladding is of U-shaped cross-section.

7. A glazed fire-resistant screen according to any of claims 2 to 6, further comprising sealing gaskets fitting between the edge of the cladding and the glazing panel.

8. A glazed fire-resistant screen according to claim 7, wherein the sealing gasket has a tongue portion fitting between the face of the glazing panel and the edge of the cladding, and a flange portion fitting outside the cladding, overlapping the edge of the cladding.

9. A glazed fire-resistant screen according to claim 8, wherein the tongue portion has projecting ribs on one side for gripping the face of the glazing panel, and projecting ribs on the opposite side for gripping the edge of the insulating material.

10. A glazed fire-resistant screen according to any of claims 1 to 9, wherein the insulating material strips are of calcium silicate monolithic board.

11. A glazed fire-resistant screen according to any of claims 1 to 10, wherein the insulating material strips are secured to the steel tubing by means of screws.

12. A glazed fire-resistant screen according to any of the preceding claims, wherein the glazing is supported on all its edges by means of the frame members.

13. A glazed fire-resistant screen substantially as herein before described with reference to figure 1, or 2, or 3, or 4, or 5 of the accompanying drawings.