GB2232184A

GB2232184A - Door or panel

Info

Publication number: GB2232184A
Application number: GB8907893A
Authority: GB
Inventors: Bryan Garner Mcdougall
Original assignee: Leaderflush Doors Ltd
Current assignee: Leaderflush Doors Ltd
Priority date: 1989-04-07
Filing date: 1989-04-07
Publication date: 1990-12-05
Also published as: GB8907893D0

Abstract

A frame element of a fire resistant door or panel comprises a laminated array of at least one layer of friable fire resistant material (21) bonded to a layer of non-friable deformable fire resistant material (22). The deformable material is provided in order to prevent axial removal of hinge screws. The non-friable material may be thin sheet aluminium or paper laminate. The friable material may be bonded ash. A layer of intumescent material may also be provided at the door or panel edge. <IMAGE>

Description

DOOR COMPONENT The present invention relates to a frame element for use in construction of articles such as doors, frames or panels.

For a door which is intended to be fire resistant for say one and a half to two and a half hours, it is necessary for the door to retain its integrity and connection to the surrounding support frame under fire conditions for that length of time. Whilst door constructions made predominantly of metal will meet these requirements they tend to be undesirably heavy and difficult to install on site since special hinges and fittings are required.

It is desirable therefore for the door to be relatively light and thereby avoid the need for special heavy duty hinges and enable conventional fixing members such as screws to be used for hanging the door.

Under fire conditions, heat will be conducted along the hinge fixing screws and these can reach a high enough temperature to cause burning or charring of the surrounding wood. When this occurs anchorage of the screws is lost with the result that the door falls away from its hinges.

It is desirable therefore for the screws to be embedded in an incombustable material so that anchorage of the screws is unaffected by rise in temperature encountered under fire conditions.

Incombustable materials of the type suitable for incorporation in framed structures such as doors are known, for example Thermax (Registered Trade Mark). A major drawback of these materials is that they are a composite material made from particulate material such as ash and as such tend to be friable. Thus whilst such materials exhibit the required resistance to fire, it is difficult for screws to be anchored directly therein since with time the material around the screws can collapse with the result that the screws become loose.

According to one aspect of the present invention there is provided a frame element comprising a laminated array of at least a layer of friable fire resistant material bonded to a layer of non-friable deformable fire resistant material.

According to another aspect of the present invention there is provided a fire resistant door including a frame element as defined above extending along at least the side edge of the door to which hinges are to be attached and preferably at least one hinge secured thereto by screws screwed directly into the frame element.

Various aspects of the present invention are hereinafter described with reference to the accompanying drawings, in which: Figure 1 is a partial plan view, in section, of a door according to the present invention Figure 2 is a view similar to Figure 1 of an alternative construction of door according to the present invention The fire door construction 10 illustrated in Figure 1 includes a core construction 12 which is located between surface layers 14. The surface layers 14 are preferably bonded to the core construction 12 in a conventional manner and may be formed from any suitable sheet material, eg plywood.

The core construction 12 may be of any conventional structure suitable for providing the desired fire resistant characteristics. For instance, the core construction 12 may comprise a series of strips of wood 18 bonded to one another in a side by side manner as illustrated in Figures 1 and 2.

Bonded to at least the peripheral side of the core construction 12 is a frame element 20 according to the present invention.

The frame element 20 illustrated in Figure 1 includes layers 21 of a friable fire resistant material bonded to one another and two layers 22 of a deformable fire resistant material interposed between selected layers 21 of the friable material.

In use, in order to secure a hinge (not shown) to the frame element 20, a pilot bore 24 is drilled which passes through layers 21 to penetrate layers 22. A screw is then screwed along the pilot bore 24 and in so doing is anchored into both layers 21 and 22. Since layers 22 are of a deformable material the screw on passing therethrough creates an internal screw thread capable of preventing axial withdrawal (without twisting) of the screw. Thus, during normal use of the door, loads and vibrations acting on the hinge screws for causing axial withdrawal are resisted primarily by layers 22 and so the integrity of the material in layers 21 around the screws is maintained.

Since both layers 21 and 22 are formed of a fire resistant material, under fire conditions heat radiating from the screws does not adversely affect their anchorage in the frame element 20.

Layers 22 may be relatively thin since their main function is to restrain axial withdrawal of the screws and layers 21 serve to support the length of the screw.

Layers 22 can be formed of any suitable thin material which is fire resistant, and sufficiently deformable to enable a screw to pass therethrough and provide the necessary resistant to axial withdrawal by pulling forces.

Suitable materials are for example thin metal sheet, for example aluminium, or paper laminates.

Whether or not a pilot bore is necessary depends largely on the ease of penetration of the screw into and through at least the first layer 22 encountered by the screw. Resistance to such penetration causing a screw to rotate without axial movement will cause breakage of the material of layers 21 and this is undesirable. Thus generally it is expected that a pilot bore will be provided.

In Figure 1 two layers 22 are provided. It will be appreciated that a different number of layers 22 may be provided in order to create the desired resistance to axial pull on the screw. In Figure 2 a single layer 22 is provided; in other examples (not shown) more than two layers 22 may be provided.

Layers 21 are preferably formed from a bonded ash particulate material (for example Thermax). The density of these layers is preferably about 900gm/m3 and each layer is about 8mm in depth. Layers 22 when formed from a paper laminate (for example Formica - Registered Trade Mark) are each of about lmm in thickness.

Preferably the frame element 20 is of elongate form and extends along the entire length of at least the side of the door to which hinges are to be attached. Preferably the elongate frame elements 20 are located on all peripheral sides of the core construction so as to enable screws to be used on any side edge of the door.

The screws may be any type of conventional wood screw, preferably of the type having a double start thread.

It is also envisaged that the frame element 20 may be of relatively short length and may only be incorporated in those areas where anchorage by screws is needed.

In the illustrated embodiments the layer 22 closest to the side edge of the door is spaced therefrom by several layers 21. It will be appreciated that these layers 21 may be formed from a single deeper layer if desired. The laminated construction composed of thinner layers is preferred since it provides greater strength.

The side of the door is shown as having a layer of intumescent material (such as Palusol - Registered Trade Mark) inset therein.

Claims

1. A frame element comprising a laminated array of at least one layer of friable fire resistant material bonded to a layer of non-friable deformable fire resistant material.

2. A frame element according to Claim 1 wherein the friable fire resistant material is a bonded particulate ash material.

3. A frame element according to Claim 1 or 2 wherein the non-friable deformable material is a metal sheet or a paper laminate.

4. A fire resistant door including a frame element according to any of Claims 1 to 3 extending along at least the side edge of the door to which hinges are to be attached.

5. A door according to Claim 4 wherein the hinge is attached to the frame element by screws screwed directly into the frame element.

6. A door according to Claim 4 or 5 wherein the frame element is elongate and extends along the entire length of the door.

7. A door according to Claim 4,5 or 6 wherein several frame elements are provided, the frame elements extending about all peripheral sides of the door.