GB2311006A - Jointed flexible fire barriers - Google Patents

Abstract

A flexible fire barrier (10) comprises insulating layers (16a, 18a) and metallic layers (16b, 16c, 18b, 18c). The barrier also comprises two outer layers (12, 14) formed from heat-resistant woven glass fibre cloth. The layers are secured in overlying relationship by mechanical fastening means. The barrier has a joint formed between edge portions of two adjacent lengths of the barrier. At the joint, the insulating layers and the metallic layers of the adjacent lengths overlap one another and the outer layers (12, 14) of the adjacent lengths are joined together to hold the insulating and metallic layers in their overlapping condition.

Description

JOINTED FLEXIBLE FIRE BARRIERS This invention is concerned with jointed flexible fire barriers.

Flexible fire barriers are used for retarding the spread of fire through spaces where it is not practical or desirable to build dividing walls. For example, the roof space of a building may be sub-divided by such barriers.

Such barriers need to resist penetration by a fire and provide heat insulation. Typically, the barrier is suspended from a frame, to which it is attached by mechanical fasteners, and hangs down like a curtain to the floor of the space. Such barriers are supplied in sheet form, eg in a roll, having a limited width which is often narrower than the space to be sub-divided. In this case, a number of lengths are hung side-by-side with abutting edges to form the barrier. A joint has to be formed at such abutting edges in order to avoid a gap through which fire or gases could spread.

Clearly, it is desirable to form joints between the edges of adjacent lengths which are able to retard fire at least substantially as well as the remainder of the barrier. Thus, the joints should not allow the passage of gases, and should not form conduction paths for heat. It is also desirable that the joint can be created with access to one side only of the barrier.

Some types of flexible fire barrier comprise relatively thick layers of glass fibre or mineral wool providing good heat insulation. These types can be joined relatively easily by overlapping the sheets and stitching them or otherwise mechanically fastening them with non-heat conductive thread or fasteners. These barriers are, however, undesirably bulky and substitute materials of reduced thickness but equivalent fire retarding properties have been developed. Some of these materials comprise a plurality of overlying layers of relatively thin insulation material separated by layers of metal foil. In these materials, equivalent fire retardant properties are achieved with a considerable reduction in the overall thickness. However, these materials are more difficult to provide with a satisfactory joint since the use of mechanical fastenings is made more difficult by the foil, and also it is difficult to avoid the foil forming a short heat conductive path through the joint. For example, if edge portions of the barrier are folded over one another, the metallic layers all pass through the joint so formed so that they provide a conductive path. It is also desirable to avoid compression of the insulating layers in the joint, in order to avoid reduction of the insulating properties.

It is an object of the present invention to provide an improved joint for adjacent lengths of a flexible fire barrier.

The invention provides a flexible fire barrier comprising insulating layers and metallic layers, the barrier also comprising two outer layers formed from heatresistant woven glass fibre cloth, the layers being secured in overlying relationship by mechanical fastening means, the barrier having a joint formed between edge portions of two adjacent lengths of the barrier, at the joint, the insulating layers and the metallic layers of the adjacent lengths overlapping one another and the outer layers of the adjacent lengths being joined together to hold the insulating and metallic layers in their overlapping condition.

In a fire barrier according to the invention, a joint is formed which is held together by the outer layers through their mechanical connection to the other layers.

The joint has more metallic and insulating layers than the remainder of the barrier and the metallic layers do not pass through the joint.

Preferably, said outer layers are joined together by mechanical fastening means, eg staples.

The insulating and metallic layers of the adjacent lengths may be interleaved in said joint.

Preferably, in order to reduce the possibility of the passage of hot gas through the joint, at least one metallic layer of each length contacts a metallic layer of the adjacent length at the joint.

In order to increase the joint's strength and further resist passage of gases, at said joint, metallic layers of the adjacent lengths may be secured together by adhesive.

It is also possible to strengthen the joint with fine plastics fasteners, eg polypropylene fasteners of the type normally used as clothes tags.

There now follow detailed descriptions, to be read with reference to the accompanying drawings, of two fire barriers which are illustrative of the invention.

In the drawings: Figures 1 and 2 are diagrammatic horizontal crosssections taken, respectively, through the first and the second illustrative fire barriers.

The first illustrative flexible fire barrier 10 comprises two outer layers 12 and 14, and two insulating assemblies 16 and 18 positioned between the two outer layers. The outer layers 12 and 14 are identical to one another and both comprise a layer of woven fabric made of E-glass fibre which has been coated with a chemical to make it heat resistant. Such a fabric is available commercially from TBA Industrial Products Limited of Rochdale, England under the tradename 'Firefly EKO 401". The layers 12 and 14 are formed from fibres having a diameter greater than 3 micrometres and have a thickness of 0.4 mm.

The insulating assemblies 16 and 18 are identical to one another and each comprises a glass fibre insulating layer in the form of a mat, 16a and 18a respectively. Each mat 16a and 18a is a needled felt made from E-glass fibre having a diameter greater than 3 micrometres. Each mat 16a and 18a is approximately 5mm in thickness and has a density of 100 kg/m3. Each assembly 16 and 18 also comprises two metallic layers formed by sheets of aluminium foil, 16b and 16c, and 18b and 18c respectively. The sheets 16b and 16c or (18b and 18c) form an envelope enclosing the mat 16a or 18a. Each sheet of aluminium foil is approximately 50 micrometres in thickness and extends across one face of a mat 16a (or 18a). The edges of the sheets 16b and 16c (or 18b and 18c) are joined together around the edges of the mat 16a (or 18a) to complete the envelope.

The layers 12, 14, 16 and 18 forming the barrier 10 are secured together in overlying relationship by mechanical fastening means in the form of stitching (not shown) made of polypropylene. The stitching holds the layers 12, 14, 16a to 16c and 18a to 18c together relatively-loosely in order to avoid compressing the insulating layers 16a and 18a which might reduce their insulating properties. The stitching is designed to melt in the event of fire releasing any compression of the layers 16a and 18a. The stitching is not shown in Figure 1 as it is positioned away from the edges of the lengths of the barrier 10 so that it does not obstruct joint formation.

Figure 1 also illustrates a joint between edge portions of adjacent lengths of the fire barrier 10. At the joint, edge portions of the assemblies 16 and 18 of said adjacent lengths overlap one another. Specifically, the assemblies 16 and 18 of the two lengths are interleaved. Furthermore, at the joint, the outer layers 12 and 14 of the adjacent lengths are joined together to hold the assemblies 16 and 18 in their overlapping condition.

To make the joint shown in Figure 1, an installer first bends edge portions of the outer layers 12 of the two lengths towards himself. He then joins these edge portions together, eg by staples, and folds them over to lie parallel to the layers 12. This creates the seam 20 shown in Figure 1. In order that the installer can work from one side only of the barrier, the seam 20 is made facing the installer and towards the centre of the barrier. Next, the installer interleaves the assemblies 16 and 18 of the two adjacent lengths of barrier 10. As shown in Figure 1, this interleaving results in the foil sheet 16b of one of the lengths contacting the foil sheet 16c of the adjacent length. Similar contacts are also made between a sheet 16b and a sheet 18b, and between sheets 18b and 18c. If desired, one or more of these contacts between the foil sheets can be secured by adhesive. Finally, the installer makes a folded seam 22 between the outer layers 14 in the same way as he made the seam 20. The seam 22 faces the installer and away from the centre of the barrier.

In the joint of the fire barrier 10, none of the foil sheets pass through the barrier. Furthermore, the joint has 4 mats 16a and 18a and 8 sheets of aluminium foil. The joint inhibits the passage of hot gases.

The second illustrative fire barrier 30 shown in Figure 2 comprises two outer layers 32 and 34 which are formed from woven cloth which is identical to that used for the layers 12 and 14 of the barrier 10. The fire barrier 30 also comprises alternating layers of aluminium foil 36 and fibre glass 38. Specifically, there are five layers of aluminium foil 36 each of which consists of a single sheet which is 50 micrometres thick and there are four layers of fibre glass 38 each of which is in the form of a non-woven tissue 1 mm in thickness made from fibres having a diameter greater than 3 micrometres. The non-woven glass fibre tissue has a density of 75 kg/m3 and is available from Fibrmat Limited. The layers of aluminium foil 36 and fibre glass tissue 38 are positioned between the woven outer layers 32 and 34.

The fire barrier 30 is held together (loosely so as not to compress the fibre glass layers 38) by mechanical fasteners (not shown) made of polypropylene. These fasteners are in the form of plastics rivets. The fasteners are designed to melt in the event of fire releasing any compression of the layers 38. The fasteners are not shown in Figure 2 as they are positioned away from the edges of the lengths of the barrier 30 so that they do not obstruct joint formation. The overall thickness of the fire barrier 30 is 5mm.

Figure 2 also illustrates a joint between edge portions of adjacent lengths of the fire barrier 30. At the joint, edge portions of the layers 36 and 38 of said adjacent lengths overlap one another. Specifically, the layers 36 and 38 of the two lengths are interleaved so that each foil layer 36 contacts a foil layer 36 of the adjacent length at the joint. Furthermore, at the joint, the outer layers 32 and 34 of the adjacent lengths are joined together to hold the layers 36 and 38 in their overlapping condition.

To make the joint shown in Figure 2, an installer first bends edge portions of the outer layers 32 of the two lengths towards himself. He then joins these edge portions together, eg by staples, and folds them over to lie parallel to the layers 32. This creates the seam 40 shown in Figure 2. In order that the installer can work from one side only of the barrier, the seam 40 is made facing the installer and towards the centre of the barrier. Next, the installer interleaves the layers 36 and 38 of the two adjacent lengths of barrier 30. As shown in Figure 2, this interleaving results in each of the foil sheets 36 of one of the lengths contacting a foil sheet 36 of the adjacent length. Similar contacts are also made between the sheets 38 of the adjacent lengths. If desired, one or more of these contacts between the foil sheets 36 can be secured by adhesive. Finally, the installer makes a folded seam 42 between the outer layers 34 in the same way as he made the seam 40. The seam 42 faces the installer and away from the centre of the barrier 30.

In the joint of the barrier 30, none of the layers 36 pass through the barrier. Furthermore, the joint has 10 foil layers 36 and 8 fibre glass layers 38, and inhibits the passage of hot gases.

Claims (6)

1A flexible fire barrier comprising insulating layers and metallic layers, the barrier also comprising two outer layers formed from heat-resistant woven glass fibre cloth, the layers being secured in overlying relationship by mechanical fastening means, the barrier having a joint formed between edge portions of two adjacent lengths of the barrier, at the joint, the insulating layers and the metallic layers of the adjacent lengths overlapping one another and the outer layers of the adjacent lengths being joined together to hold the insulating and metallic layers in their overlapping condition.

2 A fire barrier according to claim 1, wherein said outer layers are joined together by mechanical fastening means.

3 A fire barrier according to either one of claims 1 and 2, wherein the insulating and metallic layers of the adjacent lengths are interleaved in said joint.

4 A fire barrier according to claim 3, wherein at least one metallic layer of each length contacts a metallic layer of the adjacent length at the joint.

5 A fire barrier according to any one of claims 1 to 4, wherein, at said joint, metallic layers of the adjacent lengths are secured together by adhesive.

6 A fire barrier substantially as hereinbefore described with reference to, and as shown in, Figure 1 or Figure

2 of the accompanying drawings.