This invention relates to fire proofed housings for extractor fans and more especially to fire proofed housings for use with extractor fans mounted in a glazed panel or the like.

Extractor fans are generally produced from metallic and/or plastics and are commonly used to enhance the flow of air between, for example, a room and a corridor of a building. Extractor fans are commonly provided with louvred grilles which can be closed to prevent the flow of pollutants such as smoke. In the event of fire, existing extractor fans present little protection against the spread of fire between adjoining rooms or spaces. Indeed, the presence of an extractor fan can often increase the speed at which a fire can spread between other wise closed spaces. This is particularly the case when an extractor fan is mounted in a glazed panel.

This problem achieves greater significance on occasions where one of the otherwise confined spaces is a

corridor, for example, used as a fire escape between offices, rooms or the like.

The present invention sets out to provide a fire proofed housing for an extractor fan which provides an acceptable and effective fire barrier between adjoining spaces.

According to the present invention in one aspect there is provided a fire proofed housing for an extractor fan to be mounted in a glazed panel or other support, the housing comprising a pair of metallic mounting plates which in use are positioned one adjoining each face of the panel in which the extractor fan is mounted, an enclosure detachably secured to one of the mounting plates and dimensioned to receive and contain the motor of the extractor fan, the rear wall of the enclosure being defined by a grille located with or including an intumescent material which expands to close off the openings of the grille in the event of a fire, and the boundaries at least of the openings of the mounting plates which in use are to adjoin the panel faces are coated with intumescent material.

The invention will now be described by way of example only with reference to the accompanying diagrammatic drawing in which the sole Figure is an exploded view in perspective of a housing in accordance with the invention.

The housing illustrated in the drawing comprises an outer metallic mounting plate 1 formed with a suitably shaped opening commensurate with the dimensions of an extractor fan 2 to be mounted on a glass panel 3; an inner

metallic mounting plate 4 including a similarly sized opening and a box-shaped enclosure 5 formed with or including a rear grille 6. Also illustrated in the drawing is a front plate 7 of the fan 2 which overlies the mounting plate 1.

The grille 6 of the enclosure comprises a sandwich of suitably apertured metal sheets and an internal layer of intumescent material formed with an identical pattern of apertures to that of the metal sheets. Alternatively, the intumescent material may comprise a coating applied to one or both surfaces of a single apertured metal sheet. The various illustrated components are secured together by conventional fixings. Thus, the front plate and fan casing may include complementary screw threads, the mounting plates 1, 4 being drawn tightly onto the opposed faces of the panel 3 by screwing the fan casing to the plate 7. Alternatively, grub screws may be provided for this purpose. The fan and its housing may be produced from plastics, metal or a combination of plastics and metal. The front plate 7 includes a conventional smoke shutter in the form of a louvred opening 8.

In use the housing is assembled to the panel 3 with the outer and inner mounting plates 1, 4 positioned in contact with the adjoining surfaces of the panel. The boundary of the opening of each plate 1, 4 carries intumescent material to provide an effective seal between the plates and the panel in the event of a fire.

In use air is drawn through the housing by the

extractor fan via the openings of the grille 6 and the louvred opening 8 of the front plate 7 of the fan 2. In the event of a fire, the intumescent content of the grille 6 rapidly expands to prevent the passage of flame and smoke through the housing and the layers of intumescent material around the openings of the plates 1, 4 expand rapidly to provide a seal between these plates and the panel.

The housing disclosed has particular application in circumstances in which an extractor fan is designed to be mounted within a glazed panel and in circumstances where an extractor fan is positioned between a room and an adjacent fire exit.

It will be appreciated that the foregoing is merely exemplary of fire proofed housing in accordance with the invention and that various modifications can readily be made thereto without departing from the true scope of the invention.