GB2303547A

GB2303547A - Fire resistant assemblies

Info

Publication number: GB2303547A
Application number: GB9615117A
Authority: GB
Inventors: Sean Alan Wilson
Original assignee: TBA Industrial Products Ltd
Current assignee: TBA Industrial Products Ltd
Priority date: 1995-07-21
Filing date: 1996-07-18
Publication date: 1997-02-26
Anticipated expiration: 2016-07-18
Also published as: GB9615117D0; GB2303547A8; GB2303547B

Abstract

A fire cover or fire barrier to prevent flames passing through a service aperture in a wall or ceiling, such as for a light fitting, comprises a tray like assembly 1 with sidewalls 4,5 and a base 6 made from a sheet of glass fibre fabric treated with a non-intumescent char-forming composition to enhance its integrity under fire conditions. The sidewalls may be provided with marginal flaps 10 to provide additional protection for the margins of the aperture.

Description

Improvements in and relations to fire resistant assemblies This invention is concerned with at least temporarily preventing flames from passing through service openings in walls and/or ceilings. One proposal for accomplishing this is known from GB-A-2235710. This discloses a fire cover of woven fire resistant fabric supported by a structural frame to form a tent-like structure. The edges of the fabric lie against the surface of a substrate so as to surround the margins of an aperture in the latter. Whilst this type of structure is technically effective, it does require the production of not only a tent-like fabric structure, but also of a suitable supporting frame, preferably of metal. It is therefore an object of the present invention to provide a simplified construction.

In particular, it is an object of the present invention to provide a fire cover which does not require the use of any supporting structure.

Accordingly to the present invention there is provided a fire cover or fire barrier constituted by a tray-like assembly, optionally comprising a base and sidewalls, and made from glass fibre fabric treated to enhance its integrity under fire conditions. The glass fabric is preferably a texturised glass fibre fabric and the treatment to enhance integrity under fire conditions is, for example, of the kind disclosed in GB-A-2079801.

Surprisingly, it has been discovered that such a simple treated glass fibre cloth can have sufficient integrity under fire conditions to admit of its use without any supporting structural frame. In use, the assembly is used in an inverted attitude, with its edges in contact with one surface of a substrate surrounding the margins of an aperture which is to be protected.

The fire cover or fire barrier may be attached to the surface of the substrate by any convenient means, including for example, by means of screws and/or clips, although in some circumstances the use of gravity alone may be possible. It will be appreciated that in normal use, the substrate is a suspended ceiling with apertures containing, for example, light fittings. Even more surprisingly, in the latter case, the assembly can be allowed to collapse onto the back of a light fitting without compromising its performance as a fire cover.

To enhance the fire performance, the substrate-contacting portions of the sidewalls may be provided with lateral extensions or flaps which in use extend over and lie on adjacent portions of the substrate.

A woven glass-fibre fabric is preferred, preferably one based on textured yarns. It may be formed into the tray-like assembly of this invention in any convenient manner, for example, by cutting and sewing. If desired, the assembly may be provided with at least one air vent. This may be preferred where the aperture contains a light fitting which may otherwise overheat.

Fabric densities in the range 200 to 3000 g/m2 may be employed, more preferably in the range 500 to 1200 g/m2.

In order that the invention be better understood, a preferred embodiment of it will now be described by way of example with reference to the accompanying drawing in which: Figure 1 is a schematic view of a fire cover or fire barrier according to the invention, Figure 2 is a perspective view of the fire cover or fire barrier of Figure 1 located above a suspended ceiling.

Referring firstly to Figure 1, a box-like glass fibre fabric assembly 1 comprises four side walls 2, 3, 4 and 5 respectively, extending from the margins of a rectangular base portion 6. The tray is in fact a one-piece construction, made from a fabric sheet, rectangular corner portions of which have been cut away to permit folding into the configuration shown. The abutting edges of the side walls are joined by stitching (not shown), although it would be equally acceptable to use staples and/or clips.

Alternative ways of fabricating the corners and/or the complete assembly are also possible.

Referring now to Figure 2, the glass fibre fabric assembly of Figure 1 is shown in position on the upper surface of a conventional suspended ceiling. The latter comprises a plurality of ceiling tiles 11 supported by cross rails 15, 16 and the usual hangers (not shown). One such tile has been replaced by a light fitting (not shown) and to protect the aperture defined by that fitting against immediate passage of flames in the event of a fire the fire barrier of Figure 1 has been inverted, placed over the fitting and its margins secured to the adjacent tiles/rails. The base 6 and sidewalls 2, 3, 4 and 5 (not all visible in Figure 2) being non-rigid are supported by the light fitting, onto which the fabric in effect collapses.

Because of the flexible textile nature of the assembly 1, it was easily installed by temporarily displacing a ceiling tile to form an access gap. The folded or rolled up fire barrier was introduced from below, opened out, placed over the light fitting and secured in place, with minimal difficulty and more easily than prior art products which required dismantling and then reassembly in situ above the ceiling.

The fabric was a 900g/m2 woven glass fibre textile, without any reinforcement. The cloth was woven from texturised glass fibre yarn and it was treated with a non-intumescent char-forming composition of the kind disclosed in GB-A-2079801. On fire testing, the fire performance was very satisfactory, despite the lack of any conventional structural integrity of the kind imparted by a supporting frame of some sort. The test in this case was carried out using a proprietary suspended ceiling system which had already a one hour fire rating under BS476, part 23:5, 1987 (protecting steel beams).

Although not described in detail here, the individual sidewalls 2, 3, 4 and 5 may be provided with marginal flaps, as for example indicated at 10 by dotted lines in Figures 1 and 2. Such flaps may serve to enhance fire performance by providing additional protection for the margins of the light fitting (or other) aperture.

Claims

1. A fire cover or fire barrier for at least temporarily preventing flames from passing through a service aperture in a wall or ceiling, comprising a tray-like assembly made from a glass fibre fabric treated to enhance its integrity under fire conditions.

2. A fire cover or fire barrier according to claim 1 having separate base and sidewall members joined to form a box or tray.

3. A fire cover or fire barrier according to claim 1 made from a single piece of fabric.

4. A fire cover or fire barrier according to any preceding claim wherein at least one of the margins of the tray is provided with a lateral extension in the form of a flap.

5. A fire cover or fire barrier according to any preceding claim wherein the fabric is woven from texturised glass fibre yarn.

6. A fire cover or fire barrier according to any preceding claim wherein the fabric is treated with a non-intumescent char forming composition.

7. A fire cover or fire barrier according to any preceding claim wherein the glass fabric has a fabric density in the range 200 to 3000g/m2.

8. A fire cover or fire barrier according to any of preceding claims 1 to 6 wherein the glass fabric has a fabric density in the range 500 to 1200 g/m2.

9. A fire cover or fire barrier substantially as described with reference to and as illustrated by the accompanying drawings.