GB2352468A

GB2352468A - Fire door

Info

Publication number: GB2352468A
Application number: GB0016584A
Authority: GB
Inventors: David Mason
Original assignee: INTRON Ltd
Current assignee: INTRON Ltd
Priority date: 1999-07-14
Filing date: 2000-07-07
Publication date: 2001-01-31
Also published as: GB9916451D0; GB0016584D0

Abstract

A fire door (10) which has a central core of fire resistant material (11) has an aperture which receives a fire rated glazing panel (18). The glazing panel (18) has a hardwood frame (17) which engages the aperture and preferably PVC skins (15, 16) cover the central core (11) and the hardwood frame (17). An intumescent gasket (20, fig 2) may lay between the glazing panel (18) and frame (17). The hardwood frame (17) may be formed as a first section defining a base ((24, fig 3) that extends across the width of the door, and may have a hardwood glazing bead (26) that is fixed to the base (24) once the glazing panel (18) is in place.

Description

2352468 "Fire Doors" This invention relates to fire doors and in

particular, but not exclusively, to such doors with a half - hour rating.

In our British Patent No. 2289708, we describe a method of forming glazed decorative doors comprising a central foam core which defines an aperture to be glazed, a glazing panel located in the aperture and respective surface skins extending over the f ace of the core. The glazing system described for holding the glazing panel into the aperture utilises the softness of the core for its anchorage.

It is now desirable to provide fire-rated doors which are visually extremely similar to our previously mentioned doors, but our earlier glazing system is inappropriate, because to achieve a fire-rated door, the core has to be made of a fire-rated material and is therefore, almost inevitably, much more dense. Current solutions to the glazing problem in such fire doors are based on traditional beading methods, but in that case the skins must stop short of the beads and separate cover strips are used.. This not only increases the labour involved in manufacturing the door, it also produces a visually discernible difference.

From one aspect the invention consists in a glazed fire door including a central core of fire-rated material defining an aperture to be glazed, a fire-rated glazing 2 panel located in the aperture and respective surface skins extending over the face of the core characterised in that the glazed panel includes a hardwood outer frame engaged in the aperture and in that the skins extend over the hardwood frame.

This solution overcomes the problems of the prior art arrangements, but it is not one that would naturally be selected by a man skilled in the art, because it means that if the glazed panel is broken, a new door has to be fitted.

What the applicants have appreciated, and what has not been understood by others in the trade, is that the significant increase in toughness in the fire-rated glazed panels makes this approach a viable option.

Preferably the frame defines an inwardly facing channel for receiving a sheet of glazing material or a glazing unit (such as a double-glazed unit although normally these could not be sealed) and in that case the skins may extend substantially to the glazing sheet or unit, although normally a glazing gasket would sit within the channel. It is also preferred that an intumescent gasket lies between the glazing sheet or unit and the frame.

The skins may be of PVC and the core may be made of HALSPAN (Trademark) or other suitable high density board e.g. particle board. The core may have decorative features formed in its surface and its edge may be covered with hardwood lipping.

3 The invention also includes a method of forming a fire door comprising the steps of forming an aperture in a sheet of fire-rated material, forming a glazing panel comprising a hardwood frame around a glazing sheet or unit with an intumescent gasket disposed between the frame and the unit, fixing the frame within the aperture and covering the core and the frame with PVC skins on the respective faces of the core.

In that case it is preferred that the hardwood frame is pinned and/or glued into the aperture. Prior to the location of the PVC skins the core may have decorative features routed or otherwise formed in its surface.

The above arrangements achieve the fire-rating, but does not present glazing and, in particular, reglazing problems.

It has now been determined that it is possible to achieve the half-hour rating, whilst overcoming the previously noted glazing problem, by splitting the hardwood frame into a first section which defines a base that extends across the width of the door and has an upstanding outer wall and a hardwood glazing bead which is affixed to the base once the glazing panel and the -Lntumescent gasket are in place. In that case the skin on the side of the bead may only extend up to the level of the base. There it may, for example, be retained by a formation on the bead or alternatively a vacuum formed skin may be attached over the bead to overlap with the surface skin in the vicinity of 4 the base.

Although the invention has been defined above it is to be understood it includes any inventive combination of the features set out above or in the following description.

The invention may be performed in various ways and the specific embodiment will now be described by way of example with reference to the accompanying drawings, in which:

Figure 1 is a vertical section through a glazed fire door; Figure 2 is an enlarged detail on the circle A in Figure 1.

Figure 3 is a scrap cross-section through a fire door, of another embodiment, at the lower edge of its glazed panel; Figure 4 is the corresponding view to Figure 3, of a further embodiment.

A fire door, generally indicated at 10, comprises a central core 11, which defines an aperture 12, a glazing panel generally indicated at 13, which is located in the aperture 12, hardwood lip 14 extending around the edge of the core 11 and PVC skins 15 and 16 extending over respective faces of the door 10. The panel 13 includes an outer hardwood frame 17 and a glazing sheet or glazing unit 18.

As can be seen in more detail in Figure 2, the hardwood frame 17 defines an inwardly facing channel for receiving the glazing sheet 18 and a U-sectioned intumescent gasket 20, in which the edge of the glazing sheet 18 sits. The base of the gasket does not serve any great purpose other than for ease of location and pair of strips on respective sides of the sheet 18 may be used. A glazing gasket 21 is shown on one face of the sheet 18 and an identical gasket would be provided in use on the other side. The hardwood frame 17 is pinned at 22, 23 onto the core 11 and it would usually be glued along the interface as well. The PVC sheets 15, 16 are then applied onto the assembly of the core 11 and panel 13 by the method described in our British Patent 2289708 and it will be noted that they extend substantially over the hardwood frame 17, stopping only sufficiently short of the glazed panel 18 to allow for the glazing gasket 21. There is thus no visual difference between the ordinary doors and the fire-rated doors and the construction achieved is very simple and economic for assembly on an industrial basis.

The construction also offers significant security benefits in that the glazing units 18 cannot be readily accessed, simply by the removal of a bead, as is the case with competing designs.

The design is also extremely efficient from a fire rating point of view and the doors, in tests, actually achieve a 50 minute rating, rather than the half hour rating, which is suggested by the manufacturers of the core material.

in Figure 3 the hardwood frame 17 comprises a base 24 6 and an upstanding wall 25 which forms a glazing abutment for the glazed panel 18. There is then further a hardwood bead 26 which retains the glazed panel 18. The hardwood bead is pinned through the base into the core 11 and the skin 16 extends over the base 24 to lodge in a groove defined between the base 24 and a lip 27 formed on the hardwood bead.

The Figure 4 construction is essentially identical except that the bead 25 ends flush with the base 24 and a shaped vacuum formed skin strip 28 is stuck to the bead 25 and to the skin 16 by double side adhesive tape or other suitable adhesive means, allowing ready reglazing but without any significant change to the appearance.

7

Claims

A glazed f ire door including a central core of fire-rated material defining an aperture to be glazed, a fire-rated glazing panel located in the aperture and respective surface skins extending over the faces of the core characterised in that the glazed panel includes a hardwood outer frame engaged in the aperture and in that the skins extend over the hardwood frame.
2. A fire door as claimed in claim 1 wherein the frame defines an inwardly facing channel for receiving a sheet of glazing material or a glazing unit.
3. A f ire door as claimed in claim 2 wherein the skins extend substantially to the glazing sheet or unit.
4. A f ire door as claimed in claim 2 of claim 3 including an intumescent gasket between the glazing sheet or unit and the f rame.
A fire door as claimed in anyone of the preceding claims wherein the skins are PVC.
6. A fire door as claimed in any one of the 8 preceding claims wherein the core has decorative features formed in its surface.
7. A f ire door as claimed in Claim 1 wherein the hardwood frame is formed as a first section which def ines a base that extends across the width of the door and has an upstanding outer wall and a hardwood glazing bead which is affixed to the base once the glazing panel is in place.
8. A f ire door as claimed in claim 7 wherein an intumescent gasket is positioned around the edge of the glazing panel prior to location of the bead.

is
9. A f ire door as claimed in claim 7 or claim 8 wherein the skin on the bead side extends to the level of the base.
10. A fire door substantially as hereinbefore 20- described with reference to Figure 1 and 2 or Figures 3 or 4.

ii. A method of forming a fire door comprising the steps of forming an aperture in a sheet of fire-rated material, forming a glazing panel comprising a hardwood frame around a glazing sheet or unit with an intumescent gasket disposed between the frame and the 9 unit, fixing the frame within the aperture and covering the core and the frame with PVC skins on the respective faces of the core.