GB2071743A - Panelled structures - Google Patents

Abstract

A door having panels (10) framed in members (11, 12, 13) has the fire- resistance at the thin edges of the panels (10) improved by the inclusion of an intumescent strip (19) around the periphery of each panel (10) with its opposite edges in respective slits (17 and 18) in the panels and frame members. Reference is also made to fire-retarding or low thermal conductivity material in the joints. <IMAGE>

Description

SPECIFICATION Panelled structures This invention relates to panelled structures for example, partitions, walls and door sets, consisting of at least one panel, together with surrounding jointed frame-work.

An object of the present invention is to improve the fire resistance performance of such structures, and in particular to delay the arrival of smoke, hot gas or flame on one side of the structure, following the starting of a fire on the other side.

Due to the methods of construction with such panelled structures, there are usually gaps between the various components, and in particular between the edges of the panels, and the framework they fit into, and smoke can easily get from one side of a door to the other by way of such gaps, particularly if the components of the door become warped as they are heated by the fire on one side.

In fire resisting doors there is often a restraint on the overall door thickness. If an aesthetically designed raised and fielded panel is incorporated in such a door the timber thickness at the panel edge is often insufficient to resist the action of fire for the required period.

According to one aspect of the present invention, intumescent of fire-retarding or lowthermal conductivity material is included in the joints between the frame members and the panel.

While it is possible that an intumescent paint, that is to say a paint which swells when heated, can be applied round the external joint surfaces, and prevent the initial smoke penetration it would not add significantly to the burn-through time as can happen if the material is included in the joint in accordance with the invention. The material can be applied as a preformed strip at a position where the panel is thin, and if the strip has a thin wide cross section, the edge of the panel and the edge of a corresponding groove in a frame member for receiving the panel, can both be slitted to accommodate opposite edges of the preformed intumescent strip.

According to another aspect of the present invention, a method of increasing the fire resistance of a panelled structure comprises introducing a strip of intumescent or fire-retarding or low-thermal conductivity material in joints between the panel and the frame-work, where the panel or frame-work is thinner than the structure's maximum thickness.

The edges of the panel and/orof the framework may first be slotted or groovedto receive the material.

An existing door may be dis-assembled, and reassembled after the material has been introduced.

The invention may be carried into practice in various ways, but one embodiment will now be described by way of example, and with reference to the accompanying drawings, in which: FIGURE 1 is a front view of a door incorporating joints embodying the present invention; FIGURE 2 is a section along the line Il-Il of FIGURE 1 showing details of the joints; and FIGURE 3 is an enlarged view showing details of a joint of FIGURE 2.

The door shown in FIGURE 1 is known as the 'Chelsea Type' and incorporates six raised and fielded panels 1-Q framed in rails 1 stiles 12 and muntings 13, the rails 1 1 being jointed to the stiles 12 and muntirrgs 13 by means of mortice and tenon joints.

The panels 10 are sunk and fielded on both faces to provide tapered tongues 14 around their peripheries as shown in FIGURES 2 and 3. The frame members 11, 12 and 13 are provided with grooves 15, on their moulded inner edges 16, into which the tongues 14 are wedged. There is an average clearance of 2 mm between the end of a tongue 14 and the bottom of a groove 15.

AsIit17,3mmwidebyl3mmdeepis provided in the centre of the bottom of each groove, and a slit 18,3 mm x 54 mm deep is provided in the centre of each tongue 14. An intumescent sheet 19 of Palusol for example 66 mm wide and 2 mm thick extends between each pair of slits 18 and 17. The intumescent sheet 19 extends around the periphery of each panel 10 and is but jointed at the corners (not shown).

As shown in FIGURE 2, the door set has a stop 20 containing a 10 x 4 mm groove along its length; however, no such groove is formed in the jamb. This groove contains further intumescent material retained in a P.V.C. jacket 21. The door also has around its top and side edges (but not at the hinges and latch), a groove containing intumescent material in a P.V.C. jacket 22. The jackets 21 and 22 may or may not overlap when the door is in its closed position.

If there were a fire on one side of the door, smoke would tend to pass through the joint gaps, partly because the wood tends to buckle or curl as a result of the heat. The intumescent material expands as a result of the heat and fills the gaps between the tongues 14 and grooves 1 5 in the frame members around the whole of the periphery of each panel, so that smoke and flames and hot gas can be retained on one side of the door. The intumescent material will also act as a fire barrier and add greatly to the fire life of the tapered panel edge at 24 if it extends into the tapered panel to a position where the normal timber thickness is in itself capable of withstanding the action of fire for the predetermined time.

The intumescent material in the jackets 21 and 22 expands to fill gaps between the door and the stop 20.

Palusol is the Registered Trade Mark identifying the supplier of a particular intumescent material consisting of a core of hydrated sodium silicate reinforced with glass fibre and also containing glass fibre or wire mesh. It is available in semirigid strip form. The core layer is protected by an epoxide resin coating.

Other materials which expand when heated could be used, possibly as a joint in the grooves 15 or on the tongues 14, or as a preformed strip or as a pipe in a P.V.C. or other elongate sleeve.

The invention is applicable to new doors, with intumescent material being introduced during manufacture and also to existing valuable doors which can be disassembled, fitted with the intumescent material, and reassembled.

Claims (9)

1. A panelled structure consisting of at least one panel together with surrounding jointed frame-work in which intumescent or fire-retarding or low-thermal conductivity material is included in the joints between the frame members and the panel or panels.

2. A structure as claimed in Claim 1 in which the material is applied as a preformed strip.

3. A structure as claimed in Claim 1 or Claim 2 in which the material is applied where the panel is thin.

4. A structure as claimed in any of the preceding claims in which the edge of the panel and the edge of a corresponding groove in a frame member for receiving the panel are both slitted and accommodate opposite edges of the material which is in the form of a preformed strip.

5. A panelled structure constructed and arranged substantially as herein specifically described with reference to the accompanying drawings.

6. A method of increasing the fire resistance of a panelled structure consisting of at least one panel together with surrounding jointed framework in which a strip of intumescent or fireretarding or low-thermal conductivity material is introduced in joints between the panel and the frame-work where the panel or frame-work is thinner than the structure's maximum thickness.

7. A method as claimed in Claim 6 in which the edges of the panel and/or of the frame-work are first slotted or grooved to receive the material.

8. A method as claimed in either of Claim 6 or Claim 7, in which the structure comprises a door and the door is first dis-assembled and then reassembled after the material has been introduced.

9. A method of increasing the fire resistance of a panelled structure performed substantially as herein specifically described with reference to the accompanying drawings.