The present invention relates to a smoke or fire barrier.

Smoke and fire barriers are intended to contain smoke, fire or smoke and fire. In certain applications, fire barriers are required, in others the fire barrier must also stop smoke. Whereas in others still, the lower temperature task of restricting smoke from flowing throughout a building or other construction is adequate. Insofar as heat and smoke rises it may not be necessary for a smoke barrier to extend from a ceiling all the way to the floor. For instance at an atrium, a smoke curtain dropping from the ceilings around the atrium can contain the smoke from rising up the atrium. However, where the barrier is a fire barrier, it must extend all the way to the floor.

To weigh a curtain in its descent to the floor, and to provide additional weight to keep the curtain in contact with the floor on deployment, smoke or fire barriers usually incorporate a bottom bar. These can also act to close the opening through which the curtain passes for deployment, usually in a head box.

In the extreme heat of a fire, and under the action of a fire draft on the curtain, the bottom bar can deform, typically by bowing in the middle, whereby the middle of the bottom bar lifts off the floor, or by twisting or buckling. This creates an opening at floor level through which smoke and/or fire can pass. This can allow the fire and/or smoke to spread around the building.

The object of the present invention is to provide an improved fire or smoke barrier.

According to the invention there is provided a smoke or fire barrier for closing an opening in a building, the opening having a floor, the barrier including:-

• a curtain for closing the opening;

• means for deploying and retracting the curtain; • a bottom bar attached to a lower end of the curtain, for weighing the curtain for deployment, and maintaining contact with the floor on deployment, the bottom bar including: -

• a foot connected along the length of the lower end of the curtain for weighting the curtain;

• a shoe extending the length of the foot for resting on the floor after deployment, the shoe being connected to the foot by:

* fusible links adapted to separate at elevated temperature, the fusible links holding the foot and shoe together prior to deployment and on deployment, but allowing separation thereof in the heat of a fire; and

• an additional length of curtain connected between the foot and the shoe, for closing any gap between the foot and the shoe after separation of the fusible links if the foot deforms in the heat of the fire.

Preferably the additional width of curtain is pleated for storage between the first and second sections of the bottom bar.

Preferably the fusible links are rivets connecting the first and second sections of the bottom bar.

Preferably the fusible links will separate at 60-100°C. Typically the fusible links will separate at approximately 70°C.

Usually the additional length of curtain will be of the same material as the main curtain. This will be of fire resistant material.

To help understanding of the invention, a specific embodiment thereof will now be described by way of example and with reference to the accompanying drawings, in which:

Figure 1 is a sectional view through an opening in a wall, having a barrier according to the invention; Figure 2 is an end view of the barrier of Figure I ;

Figure 3 is a side view of the bottom bar of Figure 1 with the first and second sections together;

Figure 4 is a side view of the bottom bar of Figure 1 after the fusible links have failed; and

Figure 5 is a front view of a barrier of Figure 1 in which the first section of the bottom bar has bowed away from the second section under heat.

Referring to the drawings the smoke or fire barrier 1 includes a curtain 2 rolled onto a roller 4 and mounted in a headbox 6 at the top of an opening 8 in a wall or the like in a building.

The curtain is provided with a bottom bar 10 to weigh the curtain and to rest on the floor 12 on deployment, holding the curtain against the floor, preventing smoke and/or fire from passing beneath the curtain. Usually the bottom bar will be made of metal, typically steel, or other heavy and fire resistant material.

The bottom bar includes a first section or foot 14, attached to the curtain along its length. The bottom bar also includes a second section or shoel6, beneath the foot and attached to the foot. The shoe can be used to close the headbox 6 when the curtain is retracted.

The shoe 16 is connected to the foot 14 in two ways. Firstly by a section of additional curtain material 8, extending the length of the bottom bar. Usually this will be pleated, with one end 20 attached to the foot and the other end 22 attached to the shoe. The additional curtain 18 will generally be up to on hundred centimetres in length, but may be only a few centimetres drop, depending on the width of the bottom bar. Typically it may have a drop of 30- 100cm depending on the drop and length of the barrier. Thus while the additional curtain material connects the foot and the shoe it does enable them to separate. A longer bottom bar is more likely to buckle, bow or twist, and to a greater extent, thus for a longer bottom bar, additional curtain with a greater drop will generally be used. The additional curtain will typically be pleated, or otherwise folded to fit between the two sections of bottom bar. The shoe may be provided with a pair of upstands 24 defining a space into which the folded additional curtain 22 can fit, although these will not be present in all embodiments. In addition these upstands provide for a second connection between the foot and shoe of the bottom bar.

The additional curtain material 18, will usually be of the same material as the main curtain 2. This will be material which is resistant to smoke and fire and many such materials are commercially available. The additional curtain material 18 could be of a different smoke and fire resistant material, generally one with a higher fire resistance.

In addition the foot and shoe of the bottom bar are also connected through a series of fusible links, which are designed to separate at elevated temperature. These may be in the form of rivets, 26, connecting the foot 14 and the shoe 16. As shown the rivets may pass through the upstands 24 from the shoe into the foot 14. However, where upstands are not provided, the links may be positioned anywhere along the shoe to connect to the foot. However, the fusible links should not pass through the curtain, destroying the integrity of the curtain. The fusible rivets 26 are made from a material that is designed to fail and break at a particular temperature. While the links shown are designed to fail at 70°C, they could be designed to fail between 50-150°C, typically 60-100°C. Failure of the fusible links separates the foot and the shoe, allowing them to move apart, although connected by the curtain.

In the event of a fire, the curtain 2 is deployed, with bottom bar 10 resting on the floor 12. This prevent smoke or fire from passing underneath the bottom bar. and thus to the other side of the barrier.

In high temperature conditions, and possibly under the influence of a strong fire draft, the foot of the bottom bar may start to bow, bend, buckle or twist, being made of a heavy, solid construction, generally of metal, and typically steel. This will result in at least part of the first section of the bottom bar lifting away from the floor. This could create an opening under the bottom bar through which fire and/or smoke can pass. However, with the bottom bar of the invention, when the temperature reaches that at which the fusible links fail, typically 70°C, which is lower than the temperature of which the first section may being to deform, the fusible links fail, allowing the foot 14 and the shoe 16 to separate. Thus if the foot buckles, bows or twists, while it may lift away from the floor, at least along part of its length, the shoe 16, which is significantly less heavy, and thus very much less prone to deform, stays on the floor. The additional curtain material 18 connecting the foot and shoe so that there is no gap through which fire and/or smoke could pass.

Thus in use, if the main section of the bottom bar 10 starts to deform as a result of the heat of the fire, possibly in combination with pressure from a fire draft, the integrity of the barrier, in particular at floor level, will not be destroyed. The shoe 16 of the bottom bar will remain on the floor, with the additional curtain material 18 covering any gap between it and the foot.

The invention is not intended to be restricted to the details of the above- described embodiment. For instance, while the curtain shown in provided on a roller for deployment or retraction, any deployment and retraction system may be used, for example the curtain may be pleated for storage and deployed from wires unwound from and rewound onto spindles.