FIRE AND IMPACT RESISTANT DOOR AND LIPPING

Abstract

A fire resistant door leaf (30, 32) comprises a core (42) and a lipping (50, 52) extending along at least one edge (40) of the core (42). The lipping (50, 52) is of plastic material (60) and is bonded to the edge (40) of the core, and comprises at least one strip of intumescent material (62) extending parallel to the edge (40) of the core. The at least one strip of intumescent material (62) is covered by the plastic material (60) of the lipping, and the plastic material (60) is cast or moulded against the at least one strip of intumescent material (62). The fire resistant door leaf (30, 32) may be formed by locating the at least one strip of intumescent material (62) along the edge (40) of the core and subsequently forming the lipping (50, 52) by casting or moulding the plastic material (60) of the lipping to the core in a liquid or semi-liquid state to cover the at least one strip of intumescent material (62) and curing the plastic material in situ (60).

Claims

1. A fire resistant door leaf comprising: a core; a lipping extending along at least one edge of the core; wherein the lipping is of plastic material and is bonded to the edge of the core; wherein the lipping comprises at least one strip of intumescent material extending parallel to the edge of the core; wherein the at least one strip of intumescent material is covered by the plastic material of the lipping and is sandwiched between the plastic material of the lipping and the core of the door leaf; and wherein the plastic material is cast or moulded against the at least one strip of intumescent material.

2. The door leaf of claim 1, wherein the lipping comprises two strips of intumescent material extending parallel to the edge of the core, wherein the strips are arranged to be coplanar and wherein both strips are covered by the plastic material of the lipping and are sandwiched between the plastic material of the lipping and the core of the door leaf.

3-5. (canceled)

6. The door leaf of claim 1, wherein the plastic material covering the at least one strip of intumescent material is homogenous or unitary in nature and the at least one strip of intumescent material is bonded directly to the plastic material covering it by the curing of the plastic material in contact with the intumescent strip.

7. The door leaf of claim 1, wherein the plastic material of the lipping is of polyurethane.

8. The door leaf of claim 1, wherein the lipping is bonded to the core by adhesive, heat bonding, or casting.

9. The door leaf of claim 1, wherein the lipping is formed by casting or moulding to the core in a liquid or semi-liquid state and curing in situ.

10. The door leaf of claim 1, wherein the lipping is formed by casting or moulding the plastic material in a liquid or semi-liquid state around the one or more strips of intumescent material and curing the plastic material before application of the lipping to the core.

11. The door leaf of claim 1, wherein the intumescent material comprises one or more of graphite, ammonium polyphosphate, sodium silicate or mixtures or formulations thereof.

12. The door leaf of claim 1, wherein the exterior surface of the lipping is arcuate or substantially semi-circular in cross-section.

13. The door leaf of claim 1, wherein the lipping is substantially rectangular in cross-section.

14. A method of forming a fire resistant door leaf, the method comprising: assembling a core of a door leaf; providing at least one strip of intumescent material along at least one edge of the core; and bonding a lipping of plastic material to the at least one edge of the core, such that the at least one strip of intumescent material is covered by the plastic material of the lipping and is sandwiched between the plastic material of the lipping and the core of the door leaf.

15. The method of claim 14, wherein the method comprises locating the at least one strip of intumescent material along the at least one edge of the core and subsequently forming the lipping by casting or moulding the plastic material of the lipping to the core in a liquid or semi-liquid state to cover the at least one strip of intumescent material and curing the plastic material in situ.

16-17. (canceled)

18. The method of claim 14, wherein the lipping is bonded to the core by adhesive, heat bonding or casting.

19. The method of claim 14, wherein the plastic material of the lipping is of polyurethane.

20. The method of claim 14, wherein the fire resistant door leaf comprises: a core; a lipping extending along at least one edge of the core; wherein the lipping is of plastic material and is bonded to the edge of the core; wherein the lipping comprises at least one strip of intumescent material extending parallel to the edge of the core; wherein the at least one strip of intumescent material is covered by the plastic material of the lipping and is sandwiched between the plastic material of the lipping and the core of the door leaf; and wherein the plastic material is cast or moulded against the at least one strip of intumescent material.

21-34. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0067] The invention will be described, by way of example only, with reference to the drawings in which:

[0068] FIG. 1 shows part of a prior art door leaf with a strip of intumescent material;

[0069] FIG. 2 shows a partial sectional view through another prior art door leaf with a separate edge guard;

[0070] FIGS. 3A and 3B each show a partial sectional view through a pair of door leafs according to a first aspect of the present invention;

[0071] FIGS. 4A and 4B each show a partial sectional view through door leafs according to a first aspect of the present invention;

[0072] FIG. 5 shows a partial sectional view through a door leaf according to a second aspect of the present invention;

[0073] FIG. 6 shows a partial sectional view through another door leaf and door frame according to a second aspect of the present invention;

[0074] FIGS. 7 and 8 show an elevation and a sectional view of a door leaf according to the present invention; and

[0075] FIGS. 9 and 10 are schematic sectional views showing a method of manufacturing a door leaf according to the present invention;

DETAILED DESCRIPTION OF THE DRAWINGS

[0076] FIG. 3A shows a pair of door leafs 30, 32 according to a first aspect of the present invention. The door leafs are mounted in a door frame (not shown) by means of hinges or pivots on their longitudinal edges opposite to their free longitudinal edges 40 seen in FIG. 3A. The door leaf comprises a core 42. Optionally the core 42 comprises separate surface panels 44 of timber veneer or other decorative surface material (shown on door leaf 32). Attached to the free longitudinal edge 40 is a lipping 50, 52 of plastic material 60, typically polyurethane, which is bonded to the edge 40 of the core 42. However any suitable plastic material 60 can be used for the lipping 50, 52.

[0077] The lipping 50 on the first door leaf 30 comprises two strips of intumescent material 62 extending parallel to the edge 40 of the core and surrounded by the plastic material 60 of the lipping 50. In this embodiment the intumescent strips 62 are surrounded or encapsulated by the plastic material 60, providing improved protection to the strips 62, particularly if the lipping 50, including the strips 62, is formed as a separate item, and must be stored and/or transported before being bonded to the edge 40 of the core 42.

[0078] The lipping 52 on the second door leaf 32 comprises two strips of intumescent material 62 extending parallel to the edge 40 of the core and sandwiched between the plastic material 60 of the lipping 52 and the longitudinal edge 40 of the core 42, so that the strips of intumescent material 62 are covered by the plastic material 60 of the lipping 52.

[0079] The intumescent material 62 may be selected from graphite, ammonium polyphosphate, sodium silicate or mixtures or formulations thereof, but is not limited thereto. Any intumescent material which meets the appropriate fire resistance requirements may be used.

[0080] Each lipping 50, 52 is bonded to the core 42 by adhesive, heat bonding or casting. A preferred method of construction is forming the lipping 50, 52 by casting or moulding to the core 42 in a liquid or semi-liquid state and curing in situ. The strips of intumescent material 62 may be held in place while the plastic material 60 is poured into a mould held against the edge 40 of the core 42, or alternatively, in the embodiment of the door leaf 32, the strips of intumescent material 62 may be secured to the longitudinal edge 40 of the core 42 before the mould is placed against the edge 40 of the core 42 and the plastic material 60 is poured into the mould.

[0081] Another preferred method of construction is forming the lipping 50, 52 by casting or moulding separately, before subsequently bonding the lipping 50, 52 to the core 42. The lipping 50, 52 may be formed by casting or moulding the plastic material in a liquid or semi-liquid state and curing in situ. The strips of intumescent material 62 may be held in place in a mould while the plastic material 60 is poured into the mould, or the lipping may be formed by injection or extrusion moulding around the strips of intumescent material 62, which are fed at the same speed as the plastic material is injected. The lipping 50, 52 may then be formed in a separate location from the location of the door leaf manufacture. The cured lipping 50, 52, complete with integrated tumescent strips 62, is then bonded to the core 40 by adhesive or any other suitable bonding method. This method of forming the lipping is particularly suitable for the lipping 50 in which the strips of intumescent material 62 are surrounded or encapsulated by the plastic material 60. The plastic material 60 surrounding the intumescent strips 62 is homogenous or unitary in nature, and has no construction joints or gaps in it, so that the intumescent strip 62 is completely surrounded or encapsulated by the plastic material 60, at least in the transverse cross-sectional plane of the lipping 50. The intumescent strip 62 is effectively bonded directly to the plastic material 60 surrounding it by the curing of the plastic material 60 in contact with the intumescent strip 62. The intumescent strip 62 is thereby conjoined with the plastic material 60.

[0082] The strips of intumescent material 62 are protected by the strong and tough plastic lipping 50, 52, so that the performance of the intumescent material cannot be reduced by impact damage or vandalism. The lipping 50, 52 may be substantially rectangular in cross section, or may be tapered in thickness from one side of the core 42 to the other, to suit the opening movement of the door leaf 30, 32.

[0083] Typically the lippings 50, 52 are separated by a clearance gap 64 of between 2 and 8 mm when the door leafs 30, 32 are mounted in a door frame. The gap 64 must be large enough to allow the door leafs to open without interference, but small enough to allow the gap to be filled by the lipping 50, 52 and/or intumescent material 62 when the intumescent material expands upon exposure to heat of a fire.

[0084] FIG. 3B shows another pair of door leafs 130, 132 according to the first aspect of the present invention. Components which are the same as those described above with reference to FIG. 3A have the same reference number and are not further described.

[0085] The lipping 50 on the first door leaf 130 comprises two strips of intumescent material 62 extending parallel to the edge 40 of the core and surrounded by the plastic material 60 of the lipping 50. This lipping 50 of this embodiment may be formed by casting or moulding the lipping separately while encapsulating the intumescent strips 62, before adhering the cured lipping 50 to the edge 40 of the core 42.

[0086] The lipping 54 on the second door leaf 132 comprises two strips of intumescent material 62 extending parallel to the edge 40 of the core and sandwiched between the plastic material 60 of the lipping 52 and the longitudinal edge 40 of the core 42, so that the strips of intumescent material 62 are covered by the plastic material 60 of the lipping 52. In this embodiment the strips of intumescent material 62 are placed in grooves 66 formed in the edge 40 of the core 42. This embodiment is best formed by casting in situ on the edge 40 of the core 42.

[0087] FIGS. 4A and 4B each show another door leaf 230, 232 according to the first aspect of the present invention. Components which are the same as those described above with reference to FIG. 3A have the same reference number and are not further described.

[0088] In FIG. 4A the lipping 56 comprises two strips of intumescent material 62 extending parallel to the edge 40 of the core 42 and surrounded by the plastic material 60 of the lipping 50. The core 42 is formed with a longitudinal tongue 46 on its longitudinal edge 40, and the lipping 56 has an exterior surface 68 which is arcuate or substantially semi-circular in cross-section.

[0089] The tongue 46 provides additional shear resistance when the lipping 56 is subject to impact forces perpendicular to the plane of the door leaf 230. The exterior surface 68 can have any suitable shape, because the strips of intumescent material 62 are protected inside the plastic material 60 of the lipping 56.

[0090] The door leaf 232 is similar to the door leaf 32, but the thickness of the lipping 58 is constant, unlike the tapering thickness of the lipping 52 illustrated in FIG. 3A. The lippings 56, 58 of FIGS. 4A and 4B can be formed in situ on the core 42, or can be formed separately, as described above.

[0091] Although the illustrated examples of FIGS. 3A, 3B, 4A and 4B show two coplanar strips of intumescent material 62 in each lipping 50, 52, 54, 56, 58, it is to be understood that the door leaf 30, 32, 130, 132, 230, 232 of the present invention may include a single strip of intumescent material 62, or, if required, more than two strips of intumescent material 62. The strips 62 may be arranged in different positions in the lipping 50, 52, 54, 56, 58 other than those shown in the drawings. The number, position and size of the strips of intumescent material 62 are chosen dependent upon the fire rating of the door leaf, the type of door leaf, the materials of the door leaf, the thickness and size of the door leaf, and/or the proposed environment of use of the door leaf.

[0092] With reference to FIGS. 5 to 10, there is shown a door leaf 330 according to a second aspect of the present invention. The door leaf is mounted in a door frame 380, best seen in FIGS. 7 and 8, by means of hinges 382 or pivots on its longitudinal edge 384 opposite to the free longitudinal edge 340 seen in FIG. 5. The longitudinal edges 340, 384 are vertical edges when the door leaf 330 is mounted in the door frame 380. The door leaf 330 comprises a core 42. The core 42 comprises separate surface panels 44 of timber veneer or other decorative surface material. Attached to the free longitudinal edge 340 is a lipping 350 of plastic material 60, typically polyurethane, which is bonded to the edge 340 of the core 42. However any suitable plastic material 60 can be used for the lipping 350.

[0093] FIG. 6 also shows a door leaf 330A according to a second aspect of the present invention. The door leaf is mounted in a door frame 380 by means of hinges or pivots on its longitudinal edge opposite to the free longitudinal edge 340 seen in FIG. 6. The door leaf comprises a core 42. In this embodiment the core 42 itself forms the exterior surface of the door leaf 330A. Attached to the free longitudinal edge 340 is a lipping 350 of plastic material 60, typically polyurethane, which is bonded to the edge 340 of the core 42, and is similar to the lipping 350 shown in FIG. 5.

[0094] The lipping 350 has a channel shape in cross-section with a web 352 and first and second flanges 354 substantially perpendicular to the web 352. The interior surfaces 356 of the web 352 and flanges 354 are bonded to the core, and the exterior surfaces 358 of the flanges 354 are coplanar with the exterior surfaces of the surface panels 44 of the door leaf 330 of FIG. 5, or with the exterior surface of the core 42 itself in the door leaf 330A of FIG. 6. Typically the flanges 354 have a depth, i.e. the distance by which the flanges 354 extend from the web 352, of between 10 and 50 mm.

[0095] The lipping 350 is formed by placing a mould 386 adjacent to the free edge 340 of the core 42. As can be seen from FIG. 9 the free edge 340 of the core is formed with recessed cut out portions on each side of the core, the recesses having a depth equal to the required thickness of the flanges 354 of the lipping 350, thereby forming a longitudinal tongue 46 at the free edge 340. The mould 386 is shown schematically in FIGS. 9 and 10, but may be made up of several components, which together form a mould surface corresponding to the exterior surface of the lipping 350 to be formed on the door leaf 330, 330A. The mould 386 is placed against the opposed exterior surfaces of the door leaf 330, as shown in FIG. 10, and is filled with plastic material 60, preferably polyurethane, in a liquid or semi-liquid state. The plastic material 60 is cured in situ to form a hard lipping which is bonded to three sides of the tongue 46 on the free edge 340 of the core 42. The mould 386 can then be removed.

[0096] Although the embodiments of FIGS. 5 to 10 are shown without strips of intumescent material, it is to be understood that the lipping 350 can include strips of intumescent material 62 as described with reference to FIGS. 1 to 4.

[0097] Although the lipping 50, 52, 54, 56, 58, 350 is described on one longitudinal edge 40, 340 only of the door leaf core 42, it is to be understood that a lipping according to the invention can be applied to any edge of the door leaf core 42.

[0098] The intumescent material can be, but is not limited to, graphite, ammonium polyphosphate formulations or sodium silicates, and can take the form of strips of material or slurry or paste formulations.

[0099] In the door leafs according to the invention, the intumescent material is formed within the lipping in such a way that it is not visible on the edges or faces of the door. The lipping of the present invention may vary in shape and dimensions and is not limited to the shapes depicted in the drawings. The dimensions, locations and types of intumescent materials used in the invention may vary and the invention is not limited to the shapes of the strips of intumescent material illustrated in the drawings.

[0100] The plastic material of the lipping 50, 52, 54, 56, 58, 350 may be polyurethane or PVC or any other plastic material which may be formed by moulding and which may be bonded to the edge of a door leaf to provide a strong and impact resistant lipping.

[0101] The core of the door leaf may be of any construction, framed or unframed, and of any material or combination of materials, with or without separate surface panels.

[0102] The invention is not limited to the specific embodiments described, and modifications and alternatives are possible. The shape, material and size of the various components can be modified.