Improvements in or relating to intumescent fire seals

Abstract: An intumescent fire seal for location about a structure such as a door or door frame comprises an elongate flexible strip (4) of plastics material to one surface of which is secured a brush or blade seal (2) which upstands from that surface. A layer of intumescent material (1) is bonded to at least part of the strip surface.

Description: This invention relates to intumescent fire seals and to methods of producing the same. The invention also relates to one or more component parts of such fire seals and to combined smoke and fire seals. Fire seals are conveniently located in or around the edges of doors and door frames to seal the gap therebetween in the event of fire. Hitherto, such fire seals have comprised an intumescent strip encased or partially encased within a rigid or semi-rigid plastics sheath which in use is rebated into a channel set in the door or frame edge. A brush of a nylon material or a neoprene angle blade may be upstanding from the plastics sheath to inhibit the passage of smoke. Such conventional seals suffer from a number of disadvantages, these including relatively high costs of manufacture and installation, the need for special routing tools during assembly and an inability to flex in a longitudinal sense whereby the seal can only be applied to relatively flat surfaces. The present invention sets out inter alia to provide an intumescent fire seal which does not suffer from, or at least alleviates, these disadvantages. Fire seals are known from GB-A-1586362 and US-A-3566541 which include backing strips which support layers of intumescent material and, in the case of GB-A-1586362, a brush seal. The fire seal of GB-A-1586362 teaches that the intumescent material should extend across the full width of the backing strip. Neither of these documents disclose the post-characterising features of claim 1 appended hereto. In accordance with the present invention there is provided an intumescent fire seal for location about a structure such as a door or door frame, the fire seal comprising an elongate backing strip to one surface of which is secured an upstanding brush seal including a fin positioned within the lateral confines of the brush seal and a layer of intumescent material, the fire seal being characterised in that the fire seal is flexible and its backing strip has a width greater than that of the brush seal (2) which is positioned along one edge of the backing strip (1), and double sided adhesive tape for adhering the fire seal to the door or door frame on which it is to be located, the layer of intumescent material (4) being bonded to the surface of the flexible backing strip (1) and extending over only that portion of the surface of the flexible backing strip which is not covered by the brush seal. The backing strip may be produced, for example, from polypropylene, polyvinylchloride or nylon. Other materials having the required characteristics of longitudinal flexibility and ability to support and carry the elongate brush seal may be employed. The brush seal may be secured to the backing strip by stitching. However, other permanent means of securing the brush seal to the backing strip may be employed. The surface of the backing strip from which the brush seal and fin upstands may be coated with an adhesive material. This coating may be applied by a hot melt technique. In this arrangement, the surface of the backing strip so treated may have a roughened texture. The adhesive surface may be protected by a removable strip of paper or the like. A strip of intumescent material may be applied to the surface of the backing strip from which the brush seal is upstanding. The invention will now be described by way of example only with reference to the accompanying diagrammatic drawings in which:- Figure 1 is a plan view from above of a fire seal in accordance with the invention; and Figure 2 is a section taken along line II-II of Figure 1. The fire seal illustrated in the drawings comprises a backing strip 1 of a plastics material such as polypropyene, polyvinylchloride or nylon from one surface of which is upstanding a dense bristle brush seal 2 of nylon or other suitable material. The brush seal 2 is secured permanently to the backing strip 1 by stitching or other conventional means. As will be seen from the drawings, the brush seal is positioned along one edge of the strip. Alternatively the brush seal may be positioned along either or both edges or may be positioned intermediate these edges. A fin 3 of a plastics material is positioned within the boundaries of the brush 2 and extends lengthwise therewith. The fin 3 provides a physical barrier to the flow of smoke or other gases. The upper surface of the backing strip 1 is coated with an adhesive material to enable a strip of flexible intumescent material 4 to be bonded thereto. The intumescent layer 4 may be applied to the backing strip 1 when the brush seal 2 is attached to the strip, or at some later time. In this latter case, the adhesive coating is protected by, for example, a removable strip of paper or the like. The adhesive coating may be applied by a hot melt technique; to assist bonding, the upper surface of the backing strip may be formed with a roughened texture. A neoprene angle blade may be employed as an alternative to the brush seal. Typically, the intumescent strip 4 is based on a mixture of graphite/vermiculite or hydrated sodium silicate, these being two examples only of suitable intumescent materials. The strip may be coated with an epoxy resin to preserve the water content of the material. Typically, fire seals in accordance with the invention are manufactured in widths of, for example, 10mm, 20mm and 25mm. The thickness of the seal is typically between 0.75mm and 3mm. In use, fire seals in accordance with the invention can be readily and quickly attached to the edges of a door or door frame by means of double sided adhesive tape. Panel pins or the like may be employed to secure each end of the strip to the door or frame. The fire seal can either be rebated into the edge of the door or door frame or be surface mounted. The seal can readily be shaped around lock areas with a sharp knife or the like. The seal can be overpainted and is not affected adversely by water or chemicals. Upon a fire occurring, the brush 3 or blade seal acts initially to inhibit the flow of smoke between the door and its frame. As the temperature surrounding the seal rises to, for example, 105°C, the multi-directional intumescent layer is activated and expands to provide a positive pressure of, for example, 14 bar within the gap between the door and its frame to effect a fire, smoke and airtight seal therebetween and to hold the door in position. It will be appreciated that the intumescent fire seal described is merely examplary of fire seals in accordance with the invention and that modifications can be made thereto without departing from the true scope of the invention.

Claims: An intumescent fire seal for location about a structure such as a door or door frame, the fire seal comprising an elongate backing strip to one surface of which is secured an upstanding brush seal including a fin positioned within the lateral confines of the brush seal and a layer of intumescent material, the fire seal being characterised in that the fire seal is flexible and its backing strip has a width greater than that of the brush seal (2) which is positioned along one edge of the backing strip (1), and double sided adhesive tape for adhering the fire seal to the door or door frame on which it is to be located, the layer of intumescent material (4) being bonded to the surface of the flexible backing strip (1) and extending over only that portion of the surface of the flexible backing strip which is not covered by the brush seal. A seal as claimed in claim 1 characterised in that the brush seal (2) and fin (3) are secured to the flexible backing strip (1) by stitching.

Inventors: WARD DEREK ALFRED, WARD, DEREK ALFRED
Applicants: ENVIRONMENTAL SEALS LTD, ENVIRONMENTAL SEALS LIMITED
Application year: 1990
Main classification: E06B5
IPC codes: E06B5