GB2272373A

GB2272373A - Fire barrier

Info

Publication number: GB2272373A
Application number: GB9223780A
Authority: GB
Inventors: Roy Allan Fewster
Original assignee: CAPE EXTERNAL PRODUCTS Ltd
Current assignee: CAPE EXTERNAL PRODUCTS Ltd
Priority date: 1992-11-13
Filing date: 1992-11-13
Publication date: 1994-05-18
Also published as: GB9223780D0

Abstract

A fire barrier comprises two superposed layers (4, 5) of fire resisting material held apart by meltable material in the form of spacers (6), the layers (4, 5) of fire-resisting material being provided with gas-permeable apertures (7, 8). The apertures (7) of one layer (4) are offset from the apertures (8) of the other layer (5), so that when the barrier is exposed to a fire the spacers (6) melt, the layers (4, 5) come together and the whole then forms a barrier to protect the space on one side of the barrier from the fire on the other side. The spacers (6) are suitably eutectic alloys melting in the range 90 to 160 DEG , and spring clips (9) may be provided to urge the layers (4, 5) together. <IMAGE>

Description

FIRE BARRIER This invention relates to fire barriers, and is especially concerned with the provision of a novel form of fire barrier, for particular use in cavities.

It is a requirement of a fire barrier that it should protect the space on one side of it from the effects of a fire occurring on the other side, for a specified minimum amount of time. Fire barriers of various forms are known, the simplest of which consist of sheets or boards of fireresisting material. Such are usually attached to the walls or doors of the rooms or buildings which they are intended to protect.

It is the object of the present invention to provide a fire barrier for utilisation where ventilation is required in the cavity created by a rainscreen overcladding.

According to the invention a fire barrier comprises two superposed layers of fire-resisting material held apart by meltable material, each layer of fire-resisting material being provided with gas-permeable apertures, the gaspermeable apertures of one layer being offset from the gaspermeable apertures of the other layer.

The layers of fire-resisting material suitably comprise, or are made from, boards or sheets of fibre-reinforced inorganic binder. Such materials are well known, the binder usually comprising a calcium silicate or ordinary Portland cement, and the fibrous reinforcement being mineral fibres, e.g. glass fibres (e.g. E glass) or rock wool fibres and/or cellulose fibres. A suitable material from which the layers of fire-resisting material may be made is that sold under the Trade Mark MASTERBOARD. Alternatively the layers of fire-resisting material may consist of sheets of steel.

The gas-permeable apertures may be of any shape, so long as they do not disturb the integrity of each layer of material, and so long as they are offset between one layer and the other. Typically the gas-permeable apertures may be in the form of slots.

The meltable material may be in the form of a continuous layer of material between the superposed layers (suitably an annular layer) or, preferably, it is in the form of a plurality of spacers spaced around the periphery of the superposed layers. The fire barrier works by the meltable layer or spacers melting, under the influence of the temperature of the fire, and allowing the two superposed layers to come into contact. By virtue of the apertures being offset, air, smoke and flames which otherwise would have been able to pass through the apertures of one layer into the centre of the barrier and then out of the apertures of the other layer will be prevented from passing through the barrier since each layer of fire resistant material will close the apertures of the other when the two layers come together.

The superposed layers in the fire barrier may come together, once the meltable material has melted, by the influence of gravity alone, but preferably they are positively urged towards each other, for example by means of spring clips spaced around the periphery of the barrier. The spring clips, suitably stainless steel "C" clips, may be located at the positions around the periphery of the fire barrier where the meltable material spacers are positioned.

The meltable material may be of any material which melts under the influence of the temperature of fire. Thus, the meltable material may be a wax or thermoplastic material, but from the point of view of stability and longevity it is preferably a metal alloy.

It is preferred that the meltable material should melt at a temperature in the range 90 to 1600C, most preferably between 140 and 150 cm.

Amongst suitable eutectic alloys are alloys of bismuthtin-lead, bismuth-tin-cadmium, tin-indium, bismuth-leadbismuth-tin and tin-lead-cadmium. Particularly suitable alloys are those sold by Mining & Chemical Products Limited under the designation MCP 96, 100, 103, 117, 124, 138 and 145. The latter two are particularly useful.

Further details of the invention will now be described with reference to the accompanying drawings, in which: Figure 1 is a diagrammatic illustration of a section of a wall of a building before the external cladding sheets are applied, with a fire barrier according to the invention in place; Figure 2 is a cross-sectional view along the line 2-2 of Figure 1; and Figure 3 is a plan view of a second fire barrier according to the invention.

Referring to the drawings, Figure 1 shows a section of the outside wall of a building, suitably an industrial, public, commercial or residential building, comprising sheeting rails 1 on which cladding panels, will subsequently be attached. The rails 1 are attached to the existing wall of the building (not shown) and a layer of fibrous insulation 2 is placed in the cavity between the existing wall and the sheeting rails.

Mounted in the cavity is a fire barrier 3. This consists of two sheets of fire-resisting material 4,5, separated by spacers 6 of meltable material. The sheets 4 and 5 are provided with a plurality of longitudinal slots 7,8, the slots 7 being offset from the slots 8. The sheets 4 and 5 are, as mentioned, held apart by spacers 6, but spring clips 9, suitably of stainless steel, positively bias the sheets 4 and 5 towards each other.

In normal conditions ventilating air in the cavity 10 will pass through the slots 7 and 8 and circulate freely within the cavity. In the event of a fire, the spacers 6 will melt and flow away, and the sheets 4 and 5 will be pressed together by means of the spring clips 9. Since the apertures 7 are offset from the apertures 8, all the apertures will be closed and the passage of smoke and flame from one side of the barrier to the other will be prevented.

A fire barrier 3 may be inserted at each floor level of a multi-storey building. After insertion of the fire barriers, cladding sheets will be applied to the sheeting rails 1 to complete the external wall.

Although the fire barrier has been illustrated in the horizontal position, it may be used, for example, in the vertical position, for example in ventilation ducts. For this purpose positive means of bringing the two sheets together should be used, to ensure effective blocking of the respective apertures.

Claims

1. A fire barrier comprising two superposed layers of fire-resisting material held apart by meltable material, each layer of fire-resisting material being provided with gas-permeable apertures, the gas-permeable apertures of one layer being offset from the gas-permeable apertures of the other layer.

2. A fire barrier according to claim 1 wherein each layer of fire-resisting material comprises a fibre-reinforced inorganic binder.

3. A fire barrier according to claim 2 wherein the fibre reinforcement is mineral fibre or cellulose fibre.

4. A fire barrier according to claim 2 or 3 wherein the inorganic binder is a calcium silicate binder or Portland cement.

5. A fire barrier according to claim 1 wherein each layer of fire-resisting material is a steel sheet.

6. A fire barrier according to any of claims 1 to 5 wherein the gas-permeable apertures are slots.

7. A fire barrier according to any of claims 1 to 6 wherein the meltable material is in the form of a plurality of spacers spaced around the periphery of the superposed layers.

8. A fire barrier according to any of claims 1 to 7 wherein the meltable material melts at a temperature of 90 to 1600C.

9. A fire barrier according to claim 8 wherein the meltable material melts at a temperature of 140 to 2500C.

10. A fire barrier according to any of claims 1 to 9 wherein the meltable material is a eutectic metal alloy.

11. A fire barrier according to claim 10 wherein the meltable material is an alloy of Bi-Sn-Pb, Bi-Sn-Cd, Sn-In, Bi-Pb, Bi-Sn or Sn-Pb-Cd.

12. A fire barrier according to any of claims 1 to 11 wherein the superposed layers of fire-resisting material are positively urged towards each other.

13. A fire barrier according to claim 12 in which the superposed layers are positively urged towards each other by means of spring clips spaced around their periphery.

14. A fire barrier according to claims 7 and 13 wherein the spring clips are located at the positions of the spacers.