GB2274480A

GB2274480A - Glazed fire door

Info

Publication number: GB2274480A
Application number: GB9325880A
Authority: GB
Inventors: Christopher George
Original assignee: PERMADOOR PLC
Current assignee: PERMADOOR PLC
Priority date: 1993-01-21
Filing date: 1993-12-17
Publication date: 1994-07-27
Anticipated expiration: 2013-12-17
Also published as: GB9325880D0; GB2274480B; GB9301142D0

Abstract

The glazed fire door, comprises a frame 11 and a quantity of fire-retardant material 12, is provided with a sheet 16 of wire glass accommodated in an aperture 14 in said material 12. The front and back faces of the door are clad with skins 19, 20 of thermoplastic material. The entire periphery of the sheet 16 has applied thereto a glazing channel 15 which incorporates intumescent material. Retainers 17, 18 made of heat-resistant material are pushed into the material 12 to an extent such that a portion of each retainer overlies the glazing channel; in the event of fire, the retainers prevent the sheet 16 from falling out of the door. <IMAGE>

Description

GLAZED FIRE DOOR This invention relates to a glazed fire door.

Standard fire tests (BS 476, Parts 20 and 22) are carried out at a temperature of 760 C and a door is required to act as a barrier to fire for at least thirty minutes. If a door is to be glazed, the glass will be required to be wired glass.

Doors whose front and back surfaces are covered by skins or coverings of a plastics material are becoming increasingly popular and such doors are frequently glazed. If the sheet of glass were to be held in place solely by appropriately formed profiles made of the plastics material and if the glazed door were to be subjected to the standard thirty minutes or sixty minutes fire test, the skin(s) or covering(s) of plastics material would be entirely consumed within about thirty seconds; this would result in the glazing falling out of the door and enabling the fire to get past the door.

The principal object of the present invention is to provide a construction of glazed fire door in which the glazing will be kept in place for the entire time of at least the thirty minutes fire test, and a subsidiary object is to provide a method of making such a fire door.

As employed herein, the term hardwood" is to be interpreted as including not only timber of deciduous trees whose comparatively slow growth produces compact hard wood but also an artificial timber product which is made by using the wood from some trees which is stranded (shredded) and then dried, treated and bonded to produce said artificial timber product of which one example is the product sold under the brand name INTRALLAM (Trade Mark of Trus Joint Macmillan of Canada).

According to a first aspect, the present invention consists in a fire door which includes a hardwood (as defined above) frame within whose confines is a quantity of a fire-retardant material having an aperture therein which accommodates a sheet of glass which is kept in position in said aperture by means of retainers which are spaced from one another along the periphery of the sheet of glass on both faces of the sheet of glass, each retainer being of a suitable heat-resistant metal and being so pushed into the fire-retardant material as to leave an end portion thereof overlying a part of an intumescent glazing channel which covers the edge and the marginal surfaces of the sheet of glass.

In a fire door as described in the preceding paragraph, the hardwood (as defined above) frame and the fire-retardant material and the intumescent glazing channel and the overlying end portions of the retainers are preferably all hidden from view by skins of a plastics material applied to each of the front and back surfaces of the door.

It is thought that suitable heat-resistant metals, whose cost is reasonable bearing in mind the purpose for which the retainers are used, will generally be ferrous metals; the perferred material which the Applicants use is stainless steel.

According to a second aspect, the present invention consists in a method of making a glazed fire door, said method including the following steps, namely, making a hardwood (as defined above) frame within the confines of which is placed a quantity of a fireretardant material which has an aperture therein, selecting a sheet of wired glass and applying a glazing channel made of an intumescent material to the sheet in such a manner as to cover not only the entire edge of the sheet but also the marginal surfaces on both sides (faces) of the sheet near said edge, mounting said sheet with its applied channel in said aperture by means of retainers which are spaced from one another along the periphery of said sheet on both faces of said sheet, each of said retainers being pushed into the fire-retardant material to an extent as to leave an end portion of the retainer overlying a part of said glazing channel.

In a method as described in the preceding paragraph, the front and back surfaces of the hardwood (as defined above) frame and of the fire-retardant material may be clad by respective skins of a plastics material which is such as to cover not only said surfaces but also said glazing channel and the overlying end portions of the spaced retainers, the remainder of the glass sheet being left unobscured.

The present invention will now be more particularly described with reference to the accompanying diagrammatic drawings, in which Figure 1 represents a glazed fire door made according to the present invention; and Figure 2 is a part-sectional view of the fire door taken on the line Il-Il in Figure 1.

Referring to Figure 1, there is represented therein a glazed fire door 10 which comprises a frame 11 which is made of hardwood (as defined above). Said frame encloses a quantity of fire-retardant material in the form of a sheet 12.

Referring now to Figure 2 as well, it will be seen that there is a small piece 13 of said fire-retardant material whose thickness is less than that of the sheet 12. Said piece 13 is located in an aperture 14 which is made in the sheet 12 and said piece 13 extends around the periphery of a glazing channel 15 which is applied all around the periphery of a sheet of wired glass 16.

The unit consisting of the glass sheet 16 and its applied glazing channel 15 is held in place by a series of retainers 17 and a series of retainers 18, the retainers 17 being spaced from one another along one face of the glazing channel 15 and the retainers 18 being spaced from one another along the other face of said channel. Each retainer 17, 18 has been pushed into the fire-retardant material and the outer end portion thereof overlies a part of said glazing channel. The retainers 17, 18 are made of a suitable heat-resistant metal and the preferred metal is stainless steel; the dimensions of satisfactory retainers (given by way of example only) are length 100 mm, breadth 25 mm and thickness 0.6 mm.

The opposite faces of the door are clad by skins or coverings 19, 20 of a plastics material. Said material conceals from view not only the glazing channel 15 but also the outer end portions of the retainers 17, 18.

Intumescent putty is applied between the contacting surfaces indicated by the reference numeral 21 and also between the contacting surfaces indicated by the reference numeral 22. Moreover, the glazing channel 15 incorporates intumescent material. As is known, intumescent material (which includes the intumescent putty already mentioned) is formulated to expand rapidly under the influence of heat.

The glazed fire door 10 dsecribed above is made in the following manner : The frame 11 is made up using hardwood (as defined above) and the sheet 12 of the fire-retardant material is inserted into the frame 11. The sheet 12, of 40 mm thickness, has already had the aperture 14 cut in it and another sheet of reduced thickness is mounted in said aperture; this other sheet will, after suitable operations have been carried out (to be described below), provide the piece 13 which extends around the glazing channel 15. The outside edges of the sheet 12 and said other sheet are coated with intumescent putty before being inserted into the frame 11 and the aperture 14, respectively.

The skins or coverings 19,20 for the opposite faces of the door are of vacuum-formed thermoplastic material and Figure 2 illustrates one profile form which can be given to the material in order to create decorative features. The skins or coverings 19, 20 are bonded to the assembled components 11, 12, 13 by suitable adhesive compound and the door assembly thus far created is inserted in a press, with others, for about three hours. During this time, the adhesive compound cures. At this bonding stage, the aperture 14 is completely filled by the said other sheet and the skins 19, 20 cover the enire opposite faces of the door assembly.

After removal from the press, the door assembly is placed in a machine (preferably a CNC machine) which will cut an aperture therein; the size of the aperture is indicated in Figure 2 by the reference numeral 23 and it will be appreciated that said aperture is made by cutting through the skin 19, said other sheet of reduced thickness and the skin 20.

Thereafter, the machine makes another cut in order to make possible the formation of the rebate for the glazing. This other cut is made through the relevant portions of the skin 19 and of what remains of said other sheet of reduced thickness but stops short of the skin 20; the line up to which this other cut is made is indicated by the reference numeral 24.

In fact, a thickness of about 2 mm of the fire-retardant material is left on top of the inner surface of the skin 20 together with an attached piece of other waste.

Other operations will be performed by the machine (e.g. for hinges, door levers and locking mechanisms) but these are of no concern for the description of the invention.

When the machine operations have been finished, the door assembly thus far processed is removed from the machine and an operative cuts away the 2 mm thickness and attached piece of waste mentioned above with a knife so as to get down to the inner surface of the skin 20. That exposed inner surface is then properly cleaned up to get rid of the cured adhesive.

The spaced retainers 18 are then pushed into the fire-retardant material 12, enough of each retainer being left sticking out to act as part of the means for retaining the glazing in the event of fire. Thereafter, double-sided adhesive tape is applied to the cleaned-up inner surface of the skin 20 and over the end portions of the retainers where they occur.

The unit consisting of the glass sheet 16 and its applied glazing channel 15 is then placed within the confines of the piece 13 and in contact with the double-sided adhesive tape. Intumescent putty is then squirted (with a hand-held gun) into whatever gap exists between the opposed surfaces of the piece 13 and glazing channel 15 and, thereafter, the spaced retainers 17 are pushed into the fire-retardant material 12, enough of each retainer being left sticking out to act as the other part of the means for retaining the glazing in the event of fire.

Trim 25, having the shape of a frame, is then applied to the glazing channel and to the retainers 17 whereever these occur; said trim has an adhesivecoated surface which sticks firmly to the channel and the end portions of the retainers, thus completing the manufacture of the glazed fire door.

The preferred fire-retardant material which is used is marketed under the brand name BATIBOARD, this being the Trade Mark used to distinguish the Frenchmade product from other fire-retardant materials.

The product is soft enough to make it very easy easy for the retainers 17, 18 to be pushed into the BATIBOARD with ease. There are, however, other fireretardant materials which could be used for the core of the door and these other materials (or at least some of them) are thought to be soft enough to enable an operative to push the retainers into them for the purpose described.

There are preferably sixteen retainers spaced apart from one another around the periphery of the glass sheet but that number is not in any way critical and must, in any case, be related to the size of the sheet of glass.

The stainless steel retainers which the Applicants use provide (under fire test conditions) good support for the sheet of glass once the skin of plastics material has melted and disappeared. Without the retainers, the glass sheet would simply fall out of its accommodating aperture because, although the glazing channel incorporates intumescent material formulated to expand rapidly under the influence of the kind of heat generated in a fire, the force applied to the glass by such expansion is not sufficient to keep the sheet of glass in its aperture.

Claims

1. A fire door which includes a hardwood (as defined above) frame within whose confines is a quantity of a fire-retardant material having an aperture therein which accommodates a sheet of wired glass which is kept in position in said aperture by means of retainers which are spaced from one another along the periphery of the sheet of glass on both faces of the sheet of glass, each retainer being of a suitable heat-resistant metal and being so pushed into the fire-retardant material as to leave an end portion thereof overlying a part of an intumescent glazing channel which covers the edge and marginal surfaces of the sheet of glass.

2. A fire door as claimed in Claim 1, wherein the hardwood (as defined above) frame and the fireretardant material and the intumescent glazing channel and the overlying end portions of the retainers are all hidden from view by skins of a plastics material applied to each of the front and back faces of the door.

3. A fire door as claimed in Claim 1 or Claim 2, wherein the retainers are made of ferrous metals.

4. A fire door as claimed in Claim 3, wherein the retainers are made of stainless steel.

5. A method of making a glazed fire door, said method including the following steps, namely, making a hardwood (as defined above) frame within which there is then placed a quantity of a fireretardant material which has an aperture therein, selecting a sheet of wired glass and applying a glazing channel made of an intumescent material to the sheet in such a manner as to cover not only the entire edge of the sheet but also the marginal surfaces on both sides (faces) of the sheet near said edge, mounting said sheet with its applied channel in said aperture by means of retainers which are spaced from one another along the periphery of said sheet on both faces of said sheet, each of said retainers being pushed into the fire-retardant material to an extent such as to leave an end portion of the retainer overlying a part of said glazing channel.

6. A method as claimed in Claim 5, wherein skins of a vacuum-formed thermoplastics material are applied to the front and back surfaces of said frame and of the fire-retardant material in order to cover not only said surfaces but also said glazing channel and the overlying end portions of the spaced retainers, the remainder of the glass sheet being left unobscured.

7. A glazed fire door constructed, arranged and adapted to operate substantially as hereinbefore described with reference to and as illustrated in the accompanying diagrammatic drawings.

8. A method of making a glazed fire door, said method being substantially as hereinbefore described with reference to the accompanying diagrammatic drawings.

9. Any features of novelty, taken singly or in combination, of the embodiments of the invention hereinbefore disclosed.