GB2060746A - Fire door with expanded Perlite panel - Google Patents

Abstract

A fire containment door includes a thermal insulating member constituted by bonded expanded Perlite particles as an integral part of the door. The door may consist of stiles and rails with rebated expanded Perlite panels faced with plywood and edged with hard-wood strips.

Description

SPECIFICATION Fire door This invention relates to fire containment doors ("fire doors").

The known and usual methods of manufacturing fire doors employ solid wood, gypsum, chipboard, cork, compressed fibre, blockboard, and/or asbestos, with wood strapping and exterior facings. The material are overlapped, with dead air spaces, and are laminated one to the other to provide the necessary insulation depth with the door thickness, the entire door relying upon the insulation efficiency and strength of the various laminates and other materials.

It is an object of the present invention to provide a fire door wherein the core material not only acts as protection for the stiles and middle rail of a conventional door structure but is of such inert strength as to be capable of being used as a basic part of the door structure.

According to the present invention there is provided a fire containment door including a thermal insulating member constituted by bonded expanded Perlite particles as an integral part of the door.

Thus, in one embodiment of the invention a Perlite panel of a size and shape corresponding to the overall size and shape of the door to be structured is manufactured by the method described in British Patent Specification No. 1426375 (cold formed). This panel is cut into two equal pieces in a position where the centre of the middle rail will be in the completed door. Then, a door frame is cut with the stiles and middle rail of a thickness equal to 2 inch under the required thickness of the completed door.

One of the two pieces of Perlite panel is rebated out so as to fit into the top half of the door frame constituted by stiles on three sides and the middle rail on the fourth side, the rebate being of such a depth and the frame (stiles) being of such a thickness that the face of the Perlite panel being used for the top half of the door can project through and is level with the door frame on the other side. All surfaces should be touching where they come together. The process is repeated for the bottom half of the door frame. At this juncture there are three units consisting of one complete door frame with the stile joined and the middle rail being tennoned together, and two pieces of Perlite panel rebated to fit into the spaces at the top and bottom of the door. By the very nature of the materials used there is a considerable weight and cost saving.

The completed door can now be assembled by the use of conventional methods and materials, the only difference being that an intumescent material is used to seal the crack where the two Perlite panels meet in the front centre of the midd'e rail. Surface laminates can now be applied to both door sides using conventional methods and materials. An intumescent paste should be set into a groove running completely around the leading edge of the Perlite panel in a position just in front of the point where Perlite meets the wood stile.

The extension of the stability and integrity times in completed fire doors can be varied as desired by adjusting the depth of the rebate on the edges of the Perlite panels face. As a rough guide, Q inch can give a result equivalent to a half hour test at BS 476 part 8 (1972) with T inch equalling one hour test requirements. These measurements may be altered to compensate for the requirements and test standards as set out in BS 476 part 8, Fire-Resisting Doors.

The fire door Perlite core material (no laminates) as described above was subject to BS 476 part 8 (1972) testing and suffered no loss of bond or emission of smoke or toxic gases during test periods of one and two hours.

It will be appreciated that amongst the advantages of the invention is the provision of a means for protecting any internal combustibie materials, e.g. wood, without the need to pressure impregnate the door frame and/or middle rail. The invention also enables standardisation of the manufacture of fire check doors and fire protection doors quite simply on the basis of the depth of the rebate on the Perlite panels. Furthermore, it becomes possible to upgrade existing fire check doors and fire protection doors without the use of asbestos or asbestos byproducts.

In another aspect, the invention provides a method of improving the fire containment properties of a door which comprises providing the door with a thermal insulating member constituent by bonded expanded Perlite particles.

In yet a further aspect the invention provides a panel of bonded expanded Perlite particles for use as the thermal insulating member in a door of the invention, (i.e. when intended for such use, or suitably "got up" for such use, or made or dealt with in any way for such use).

The invention will now be further described by way of the following Example.

EXAMPLE A pair of timber doors mounted in timber frames were tested for the determination of fire resistance according to BS 476: Part 8: 1972. The doorsets tested were found to satisfy the requirements of the test in respect of insulation for 54 minutes, integrity for 55 minutes and stability for 60 minutes, when the test was terminated.

The doorsets submitted to test were essentially conventional in size and appearance comprising timber stiles and rails, core panels made of bonded expanded Perlite particles faced with plywood on both sides and edged with a hardwood. Steel hinges, handles and latches were fitted.

Dimensions (each door) Overall Height 6'6" 1.981 m Width 2'9" .827 m Thickness 1 " .044 m Weight 84 Ib 38 kg excluding furniture 87 Ib 39.4 kg including furniture Detail Dimension (each door) a) Timber Stiles2x 6'6" x 3T311 x 1+" 1.981 m x .095 m x .038 m Rails2x 2'3" x 3T'' x 1T" .686 m x .165m x .038m Middle Rail 2'3.'' x 6/x 1/" .686 m x .165 mx .038 m b) Core Core material consisting of expanded perlite bonded with a mix of inert, inorganic silaceous compounds Panels2x 2'9+" x 2'2+" x 1T" .851 m x 667 m x .038 m c) Facing Birch-faced three ply Sheets 2x 6'6" x 2'8+" x 1/8" 1.98 mx 819 mx 004m d) Edging Mahogany (Sapele) 2x 6'6"x1+11x-38" (no top/bottom edging) 1.981 m x .044 m x .009 m Method of assembly a) Timber stiles and rails were cut to size and grooved to accept the cores to a depth of 't (19 mm).

b) Cores were rebated to produce a 4)1 (19 mm) tongue on all edges.

c) Conventional wood glue (Evostik (Registered Trade Mark) Resin 'W') was used to join timber stiles and rails and an adhesive of inert, inorganic, silaceous compounds was used to bond the cores into the timber framework of the doors. No nails or screws were used.

d) Clamps used to hold the whole whilst adhesives were curing, were removed and all joints flushed smooth.

e) Plywood facings were coated with the silaceous adhesive and held in position in a press until curing was completed.

f) The whole door was planed to accept edgings mounted with conventional wood glue and cramped g) The whole door was planed in order to leave 3 mm gap in the jamb when hung.

h) Door furniture was fitted with screws and intumescent plugs (purchased from Sealmaster of Cambridge).

All external faces were untreated and the doors mounted on door jambs purchased from Magnet of Redhill; these were untreated and of 21 hour rating. A groove of 21 mm x 7.5 mm was rebated therein to accept N60 intumescent strip purchased from Sealmaster of Cambridge.

Dimension of jamb Overall width 2.11/16" (69 mm) Face on closed side Width at hinge 1 4311 (44 mm) Face on opening side Depth Overall 3.11/16" (83 mm) To Furnace (Total height and width correspondingly greater than door).

For test purposes the doorsets were built into a Celcon block wall nominally 100 mm thickness, such that one door opened into the furnace and one away. Thermocouples were fixed to the unexposed face of the doors and frames and the whole assembly was conditioned according to the Standard. The assembly was then positioned so as to close the front opening of the gas fired furnace and thermocouples were positioned inside the furnace in accordance with the requirements of the Standard.

The furnace was then operated so as to produce the required time/temperature relationship on the exposed face, temperatures on both faces being monitored throughout the test by means of the previously positioned thermocouples.

The following observations were made during the test:- Time (minutes from start of test) Observations 00 Test commenced 06 Exposed faces of both doors began charring. The faces then flashed over and the faces began peeling and falling into the furnace.

08 Both exposed timber faces had fallen into the furnace.

10 Internal furnace pressure (upper half of the furnace chamber) increased to +1.0 mm water gauge. Smoke began to be exuded from all door/frame gaps.

14 Door furniture (not hinges) on the exposed face was by now melted.

20 Some bowing had developed on both doors. The door which opened into the furnace was beginning to bow towards the furnace at its top corners; the top edge of the out-opening door was bowing out.

25 Some intermittent flashing was noted along the lower edge of the out-opening door.

28 The exposed face of the out-opening door was flaming vigourously.

30 Insulation, integrity and stability were satisfactory.

54 Insulation failure occurred at the top left hand corner (viewed from the unexposed face) of the in-opening door.

55 Integrity failure occurred along the bottom edge of the out-opening door.

60 Test terminated.

Claims (8)

1. A fire containment door including a thermal insulating member constituted by bonded expanded Perlite particles as in integral part of the door.

2. A door as claimed in claim 1, wherein the thermal insulating member comprises a panel of bonded expanded Perlite particles.

3. A door as claimed in claim 2 comprising a door frame and middle rail and two of said panels rebated to fit into spaces provided therefor in the door frame.

4. A door as claimed in claim 1 and substantially as hereinbefore described.

5. A fire containment door substantially as hereinbefore described in the specific Example.

6. A method of improving the fire containment properties of a door which comprises providing the door with a thermal insulating member constituted by bonded expanded Perlite particles.

7. A method as claimed in claim 6 and substantially as hereinbefore described.

8. A panel of bonded expanded Perlite particles for use as the thermal insulating member in a door as claimed in claim 1.