Static structures (e.g. – buildings) – Irreversibly reactive component
Reexamination Certificate
1998-10-13
2001-05-08
Kent, Christopher T. (Department: 3635)
Static structures (e.g., buildings)
Irreversibly reactive component
C052S028000, C052S039000
Reexamination Certificate
active
06226939
ABSTRACT:
The invention relates to a fire protection cover for a downlighter, audio speaker, fan, tannoy, alarm or similar insert into a false ceiling, such as a suspended ceiling, stud partitioned wall, etc.
Modern building methods commonly use suspended ceilings or partitioned walls which are supported below or separately from the main structure of the building. Typically a suspended ceiling comprises a membrane of tiles, panels or planks supported at a specific distance below an existing soffit by a grid of metal sections. Unless the suspended ceiling or partitioned wall is adequately protected from fire, the gap between the ceiling and wall and the structure of the building may provide a route for a fire to quickly spread from one part of a building to another. Suspended ceilings and partitioned walls should therefore be as fire proof as possible. Increasingly objects such as spotlights, porthole and recessed luminaires, smoke detectors, speakers, alarm systems and other such devices have been recessed within the suspended ceiling or partition. This requires an aperture to be made in the ceiling or partition which provides a route for fire to access the void between the ceiling or partition and the structure of the building. Furthermore, such devices tend to fall out of the suspended ceiling and/or partitioning wall in the event of a fire, thus providing access for the fire to the void.
It is known in the art to provide a tent of a fire blanket material to place over the luminaire or other inserted device. This provides a degree of fire protection and prevents, to some extent access of a fire to the void. A disadvantage of such a device is that such cover tends to be easily knocked out of position and may be lost or thrown away the luminaire or other device needs refitting. Furthermore, such a device does not stop the luminaire from dropping out in the event of a fire.
According in one aspect the invention provides a fire protection cover for an electrical device recessed into a wall, ceiling or the like, such as a downlighter, said cover comprising one or more support layers, which may be of metal, coated with one or more layers of intumescent material. Preferably the fire protection cover is substantially rigid.
The provision of such cover provides a more durable cover which is capable of being handled without being damaged.
The cover may be used in suspended ceilings, stud partitions and other situations where a wall or ceiling may be separated from the main structure of the building. It is also envisaged that such cover may be used in for example rail carriages, coaches, lorries or other forms of transport where recessed devices are fitted to a suspended ceiling or partition wall. The cover may be used for a variety of recessed devices such as spotlight and porthole luminaires, recessed luminaires, smoke detectors, speakers, alarms, fans and tannoy systems.
Preferably the fire protection cover of the invention comprises a base, one or more walls and an opening for receiving the electrical device. The opening for the electrical device and/or base may be substantially circular in shape. Alternatively the opening and/or base may be rectangular, square, or another shape so that the cover can be adapted to receive different inserted devices.
Preferably the or each wall tapers towards the base. The cover therefore may be substantially frustoconical in shape.
Alternatively the cover may comprise a cylindrical wall, a base at a first end of the cylindrical wall and an aperture for receiving the electrical device at the second end. This allows the cover to be simply manufactured from a sheet of material rolled to form the cylindrical wall and a pressed out sheet of material for the base. The base and wall may be held together by conventional methods such as welding or adhesive.
The base and/or one or more walls may comprise one or more apertures for the passage of cabling from the device, such as a downlighter, to pass through. Furthermore, there may be at least 1, especially 5 to 10 , most preferably 8, apertures to allow heat from the device to escape. This prevents the intumescent material from intumescing prematurely.
The base and/or one or more walls may also be in the form of a mesh or perforated sheet of material coated with one or layers of intumescent material. This allows full ventilation of heat from the device. The apertures in the mesh are closed by the intumescent material upon exposure to heat from a fire. “Perforated sheet” is intended to mean a sheet of material comprising a plurality of apertures substantially regularly placed across the sheet.
The apertures for the cabling and/or ventilation may be closed upon exposure to heat by the intumescing of the intumescent material. However, it is envisaged that further seals, such as intumescent rubber grommets may be provided to further seal the apertures upon exposure to heat. Such seals may also provide a degree of waterproofing to the fire protection cover.
The intumescent material may be an epoxy-, graphite-, mastic-, or water-based intumescent material of the type known in the art. Preferably it is applied in a thickness of ¼-1 mm especially ½ mm thickness to the or each layer of metal.
Preferably the or each layer of metal is steel, especially mild steel, or aluminium, with a thickness of between 0.5 mm and 1 mm. Preferably the metal is in the form of a mesh or perforated sheet.
The metal may be moulded into the desired shape before coating in the intumescent material. Water-based intumescent materials are especially suitable for such a method of application to the layer of metal. Such a process results in a layer of intumescent material on the outside and the inside of the fire protection cover.
The layer of metal may be pre-primed before coating with intumescent material to ensure good adhesion of the intumescent material to the cover.
Preferably the cover is attached to the downlighter or other device to be protected.
According to another aspect of the invention there is provided a fire protection shield for an electrical item, recessed into a wall, ceiling or the like, the shield comprising a cover arranged to receive the item, the cover carrying or being made of an intumescent material and further comprising means to attach the cover to an electrical item to be protected.
It may be attached by means or one or more rivets or screws, or be friction fitted. A device such as a downlighter may additionally be suspended from the base of the cover, for example by means of a threaded tube which is threadable onto the aperture for the cable in the base of the cover.
This gives the advantage that cover becomes an integral part of the downlighter or other inserted device and is less likely to be omitted or lost.
The cover and/or downlighter may rest upon the ceiling surrounding the aperture into which the downlighter or other device is inserted. Alternatively it may be attached to the ceiling and/or wall by means of one or more brackets or wire or metal stays attaching the cover to runners for the ceiling and/or partition. The fire protection cover may additionally be mounted on one side of a ceiling and/or partition wall and attached to a finishing ring which surrounds the aperture on the other side of the ceiling and/or partition wall. The cover may be attached to such a finishing ring by means or one or more brackets.
Upon exposure to heat the intumescent material will expand and help to fill any gaps between the ceiling and/or partition wall, thus preventing the entry of fire into the roof or wall voids. Further seals may be additionally provided between the cover and the ceiling, wall, downlighter or other inserted device, or the finishing ring. Such seals are preferably made of an intumescent rubber of the type known in the art, and provide further means to ensure that fire does not enter the ceiling and/or wall void. Such seals may also prevent the ingress of moisture.
The presence of intumescent material on the or each layer of material on the cover also ensures the prevention of the transmittal of heat
Atkins Clive Anthony
Maris Nigel Christopher
Kent Christopher T.
Kilpatrick & Stockton LLP
Nullifire Limited
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