GB2363354A - Decorative glass fibre reinforced, low smoke, fire retardant mouldings - Google Patents

Abstract

A method of manufacturing glass-fibre-reinforced, low-smoke, fire-retardant decorative mouldings comprises the steps of applying a gel coat mixture to a mould surface to form a gel coat layer 3, curing the gel coat layer to form a low-smoke, fire-retardant presentation layer, applying a layer of glass fibre matting 4 to the presentation layer, applying a layer 5 of back-up resin mixture to the layer of glass fibre matting, applying further alternative layers of glass fibre and back-up resin to form a pre-determined thickness of layered material and curing the back-up resin of the layered material to form a low-smoke fire retardant moulding. Also disclosed are the use of such mouldings for fabrication of fire-retardant enclosures and fire doors. The mould surface may be polished to produce a gloss finish on the moulding. If some texture is required then the texture may be given to the mould surface.

Description

2363354 DECORATIVE GLASS FIBRE REINFORCED, LOW-SMOKE, FIRE RETARDANT

MOULDINGS This invention relates to a method of manufacturing of decorative, glass fibre reinforced, low-smoke, fire retardant mouldings.

5 There is a requirement in hazardous and safety-critical environments for low-smoke, fire retardant decorative mouldings. Such environments include ollrigs, shipping, ferries and C subway trains. Methods of manufacturing moulded panels from phenolic mouldings are known.

1 However, such phenolic mouldings can be coloured or made decorative only by painting.

Unfortunately, the paint layer increases the smoke emission and carbon monoxide emission 10 from the mouldings in a fire. It is therefore necessary to use low- smoke, low-toxicity paints for safety-critical environments. However, in, for example, building cladding applications the paint layers prevent the painted panels passing fire tests. Moreover, if the painted mouldings are scratched the underlying colour of the moulding shows through. There are also problems with removing graffiti without damaging the paint surface. Moreover, the painting stage of 1 l> Z:1 15 manufacture adds considerably to the cost of the finished panel. In addition, phenolics have to be heat-cured which affects their colour, so that it is not always possible to predict their final colour.

Uncoloured glass fibre reinforced unsaturated polyester resins with fire proofing filling Z such as aluminium hydroxide have lower carbon monoxide and smoke emission than even 20 unpainted phenolics commonly used. However, the materials used in their manufacture are notoriously difficult to handle, the heavily filled resins being viscous and treacly and, moreover, the resultant panels cannot successfully be painted.

The object of the present invention is to ameliorate these difficulties.

According to a first aspect of the invention, there is provided a method of manufacturing 25 glass fibre reinforced, low-si-noke, fire-retardant decorative mouldings comprising the steps of..

a) providing a mould having a mould surface; b) providing a gel coating mixture suitable for W 1 C> W Z2 forming a low-smoke, fire retardant cure; c) applying the gel coatine, mixture to the mould 1 - - surface to form a gel coat layer. d) curing the gel coat layer to form a low-smoke, fire 1 W 1=) retardant presentation layer; c) providing glass fibre matting; f) applying a layer of the glass 30 fibre matting to the presentation layer., g) providing a back-up resin mixture for forming a low- smoke, fire-retardant cure, h) applying a layer of the back-up resin mixture to the layer of glass fibre matting, i) applying further alternate layers of glass fibre and back-up resin mixture to c form a pre-determined thickness of layered material., j) curing the back- up resin mixture of the layered material to form a low-smoke, fire- retardant moulding, and k) removing the moulding 5 from the mould.

Advantageously, step a) includes providing a mould with a polished, matt or textured mould surface.

Preferably, step b) includes the steps of.. b 1) mixing a polyester resin, an accelerator, and a wetting agent; b2) adding sufficient thixotropic material to raise the viscosity of the mixture 10 to a predetermined viscosity value, b')) gradually adding filling, powder and thoroughly mixing into the mixturel and M) mixing in a curing catalyst.

Advantageously stel) b I) comprises inixing, in the ratios 6 kg polyester resin: 60 ml -100 ml of accelerator: 40 ml - 90 m] wettin2 aoent.

W -'.Y Preferably, step b 1) comprises r-nixin., in the ratios of 6 kg polyester resin - 90 mI 15 accelerator: 40 ml wettino acient, W 1 Conveniently step b 1) comprises inixing a pigment with the polyester resin, accelerator and wetting agent.

Advantageously, step b I) comprises inixing in the ratios 6 kg polyester resin. 60 nil - 1.) -71 rril accelerator: 40 nil - 90 nil wettin(y agent. 150 cc - 400 cc of pigment.

13 _1 W 20 Preferably, step b I) comprises niixing in the ratios of 6 kg polyester resin: 90 nil accelerator: 40 nil wetting agent 300 cc piument.

Preferably, step b2) includes measuring the viscosity of the resin using a viscosity pot test before mixing, and adding predetermined quantities of thixotropic material dependant on the measured viscosity to raise the viscosity to the predetermined viscosity value.

25 Conveniently, 100 cc of thixotropic material are added for each second less than 15 seconds recorded in the viscosity pot test.

Advantageously fire retardant filling powder is added to the resin mixture in the ratio 9 kg 20 kg of filling powder: 6 kg of resin.

Preferably, fire retardant filling powder is added to the resin mixture in the ratio 3: 1 of powder to resin.

5 Conveniently, the fire retardant filling powder is aluminium hydroxide.

Preferably, step c) comprises spraying a 0.5 mm layer of the gel coating onto the mould surface.

Conveniently, step d) comprises curing the gel coat layer at room temperature for between 30 minutes and 3 hours.

10 Advantageously, step e) comprises providing woven glass matting or chopped strand glass matting and cutting the matting to fit the shape of the mould.

Conveniently, providing chopped strand glass matting comprises providing 300 gm/m 2 0 1-Y chopped strand glass matting C) Alternatively, step e) includes providing glass fibre tissue and step f) comprises applying 1 15 a first layer of the glass fibre tissue and back-up resin to the presentation layer to strengthen the gel layer and prevent the subsequent penetration of the gel layer by coarse glass fibres.

Advantageously, providing a glass fibre tissue comprises providing a printed or patterned C C) 1:1 glass fibre tissue.

Preferably, step g) comprises providing a back-up mixture in the same ratios as provided 20 for the gel layer mixture in step b) but omitting the thixotropic material.

Preferably, step h) comprises brushing the back-up resin mixture into and over the layer of glass fibre matting, Conveniently, the glass fibre layer and back-up resin together form a layer 1 mm thick.

Advantageously, step 1) comprises applying different numbers of alternate layers in 25 different portions of the mould to form different predetermined thicknesses in the different portions of the mould respectively.

Conveniently, step 1) comprises incorporating fix' 1 ing, means at least partially between layers of glass fibre and back-up resin.

Conveniently, step 1) comprises incorporating door furniture means at least partially between layers of glass fibre and back-up resin.

5 Conveniently, step i) comprises incorporating, reinforcing means at least partially between layers of glass fibre and back-up resin.

Preferably, step ') comprises curing the back-up resin mixture for over 3 hours at room j temperature.

Conveniently, cuFinu the back-up resin mixture comprises curing the backup resin 10 mixture overnight, Accordine, to a second aspect of the invention, a moulding produced by the above 1:1 method is used for the fabrication of a fire-retardant enclOSUre.

Conveniently, the moulding is used for fabrication of a fire safe.

Alternatively, the moulding is used for fabrication of room partitioning to fabricate a fire , 1 1 1 1 1 1 2, 1 15 retardant room.

According to a third aspect of the invention, there is provided a fireretardant enclosure fabricated from a moulding produced by the above method.

According to a fourth aspect of the invention, a moulding produced by the above method Z:1 is used for the fabrication of a fire door.

20 Conveniently, the moulding is used for the fabrication of a fire door having exterior z:

panels produced by the above method and a core of a non-combustible material having a lower density than the mouldino Z According to a fifth aspect of the invention, there is provided a fire door having exterior 1.

panels of mouldinos produced by the above method and a core of a noncombustible material 25 having a lower density than the mouldings.

z, z, Conveniently, the non-combustible material of the core of the fire door comprises any of calcium silicate, rock wool and mica.

One embodiment of the method of the invention provides through- coloured, decorative, glass fibre reinforced, low-smoke, fire retardant mouldings. This method provides the 5 advantage of lower smoke and carbon monoxide decorative panels than are available in the prior art. In addition, even when a panel is scratched the colour can be restored. When first scratched the scratch shows as a white line because of the filler powder released. However, this may be polished out, the polish serving to wet and seal the surface. This is particularly effective if a polish coloured with the pigment used for colourin the panel is used. The panels of the 1 - 9 10 invention have also been found to be susceptible to the removal of graffiti without serious deterioration to the decorative effect. Mouldings produced by the method of the invention have 1 particular application in the production of lightweight fire doors and fire safes.

A further embodiment provides the advantage of a decorative, fireretardant, low-smoke emission mouldin having a decorative patterned or printed surface effect, for example, a 9 Z:1 15 wood or stone effect.

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

131 C) Figure 1 shows a cross-section of a mould used in the invention., Figure 2 shows a gel layer used in the invention in the mould of Figure 1; 20 Figure 3 shows layer of glass fibre mat laid on gel layer of Figure 2; and Figure 4 shows layer of back-up gel brushed onto the glass fibre mat of Figure 3 and a 1 further layer of glass fibre laid on the back-up gel.

In the Figures, like reference numbers denote like parts.

As shown in Figure 1, in the method of the invention for the manufacture of panels, a 25 mould 1 is first produced to the required shape, in a manner known per se. The inner surface of the mould is provided with a mould surface 2 dependant upon the texture of the moulding that Z it is required to produce. Thus, if it is required to produce a gloss finish on the moulding the mould surface is polished. If sorne other texture is required than another texture may be given to the mould surface. For example, if a wood-like surface is required the mould is prepare from a wooden preform so that the mould takes Lip the texture of the wood. This is achieved by coating the wooden preform with release agent and using the wooden preform as a pattern to make a mould. If a stone texture is required sandpaper may be used to cover the preform so 5 that the mould surface has a rou,hened texture.

As shown in Figure 2, a further step of the method of the invention is to coat the mould W surface 2 with a gel coat layer 3 to provide a presentation layer in the finished panel. This sealing, or "finishing" layer provides a barrier between the glass fibre reinforcing to be added in subsequent steps of manufacture and the surface of the moulding, so that no glass fibres are 10 visible from the surface.

An example of constituents of the gel layer, their relative quantities and suitable W commercially available materials are shown in Table 1.

A suitable unsaturated polyester resin is chosen for its ability to accept a large ratio of fire retardant filler. The unsaturated polyester resin is naturally of low viscosity, unsuitable for 15 coating the vertical surfaces 10, 11 of the niould. It is therefore necessary to increase the c viscosity. In order to obtain a suitable viscosity, the viscosity of the resin is first tested before mixing, using a viscosity pot test known per se in paint manufacture. In this test, a known volume of resin is timed through a known aperture (diameter of 3111111) into a collection vessel.

The resin is passed through the pot test and the tirne the resin takes to pass through is 20 compared with a standard time and a suitable quantity of thixotropic material added to increase the Viscosity the required arnowit, to attain a pre-deteri-nined viscosity required to coat the vertical surfaces. Thus, if the standard tirne is 15 seconds, 100 cc of thixotropic material may be added to the 6 kg, of resin for each second that the time is under 15 seconds.

TABLE 1

Constituent Quantity Commercial product Manufacturer or Supplier Unsaturated polyester resin 6 k02 DSM Synolite 5001-T-1 DSM - BASF Structural Resins Accelerator 90 ml DSM 5002-T-2 DSM - BASF Structural Resins Wetting agent 40 ml BYK-W995 BYK-Chemie GmbH Thixotropic (additive) see text Aerosil 2000 Degussa material Pigment 300 cc Polyester Pigment Pastes Llwellyn Ryland Ltd Aluminium hydroxide fire 18 kg Omnya ON921 Omnya, British retardant powder Alcan Catalyst 9 ml / 1200 MEKP-HA-2 Peroxide-chemie cc of mix A wetting agent is included in the mixture to help disperse the filling powder through 0 C> the resin.

An accelerator is provided to accelerate, in co-operation with the catalyst that starts 5 the reaction, the curing of the resin.

Z:5 Pigment is used to colour the gel layer where a through-coloured panel is required.

1 1 Although aluminium hydroxide (A]2(0H)3) is listed as the fire retardant filler it will be understood that other fire retardants could be used, such as magnesium hydroxide.

The resin, accelerator, wetting agent, thixotropic material and pigment, where used, 1 W 10 are mixed before adding the fire retardant powder. The powder is added into the resin in small 1:1 amounts until thoroughly mixed. The volurne of the catalyst addition is critical because the proportion of catalyst affects the colour of the completed panel.

It is found that the gel layer cannot be satisfactorily brushed onto the mould since this results in brush lines remaining on the surface of the finished panel. It is therefore necessary to 1=1 spray the gel layer 3 onto the mould surfaces 2, 10 & 11 of the mould 1, until a layer 0.5 mm thick over the whole of the mould surface is fort- ned.

The gel layer is allowed to cure for a period between 30 minutes and 3) hours, so that glass fibre mats 4 subsequently to be added will not sink through the eel layer 3.

W 5 In an embodiment of the invention, a speckled effect may be produced by incorporating, coloured particles and mineral filler into the gel coat, and mat and high gloss finishes can thereby be obtained, giving the appearance of polished stone. A suitable P 2, 1 1 decorative surface material is available from Chromat (UK) Ltd of Blaydon oil Tyne, which may be used in applications such as wash-basins, in which the fire- retardant requirements are 10 less demanding.

It will be understood that proprietary gel layer resins are not, in generaL, suitable for the production of the fire retardant, low smoke emission panels produced by the present invention because the proprietary materials are riot hjohly filled and therefore do not meet fire tests set for such materials.

15 When the gel layer has ciii-ed, a first glass mat 4 is cut to the mould size and laid over S00 c 7 111/ 11 1 2 the gel layer 3. A suitable fibre glass rnat i _) t chopped strand mat which comprises glass strands of approxirnately 2 inch (5 ci-n) length distributed at randorn arid held together by an emulsion. Alternatively, woven -]ass rnat may be used.

Instead of a first glass inat, a glass tissue or glass veill layer may be used. This has the 20 eflect of strengthening the gel arid preventing the 'on of the gel layer by glass W - - penetrati -p fibres from subsequently laid elass fibre rnats. Such tissue can more easily be worked into corners of the mould because the tissue is thin arid flexible, thereby avoiding voids between the tissue and the gel layer. Such a tISSLIC layer may be printed or otherwise patterned and used with a colourless gel layer containing no pigment. In this manner a wood- like surface to the 25 moulding may be created, for example, by using a glass tissue printed with a woodeffect. Such 71 a surface is enhanced by the use of a wooden preform to provide a wood- textured mould 9 surface. In this way an uncoloured gel layer and uncoloured back-up resin may be used with a tissue printed with a wood-effect finish for the production of door panels. Alternative finishes include a marble finish or the tissue can be printed with a name and/or logo. z::, Similarly, a stone-like surface may be created using a sandpaper surface to form the mould and mixing sand with the gel layer. This is particularly suitable for cladding panels for n 1 1 buildings. Other applications of the moulding panel are for interior or exterior stone finishes.

The first glass mat or glass tissue is covered with back-up resin 5 by brushing the back-up resin over and into the glass mat 4 or tissue to form a 1 mm thick glass mat or tissue and resin layer. The brushing process is important for distributing the resin evenly through the w 10 glass mat, avoiding the production of voids or resin-rich areas, so that the fire retardant powder is evenly distributed throughout the panel. The back-up resin mixture is formed in the same manner as the gel layer, but with the exception of the thixotropic material which is used to increase the viscosity of the gel layer.

Further layers of glass mat and back-up resin are applied to achieve the required thickness of moulding to form a homogeneous mass. Different numbers of layers may be built g w Z:1 up in different portions of the mould to produce panels having different thickness in different W portions of the panel. Strands of glass fibre may be incorporated lying in a particular direction to tailor strength of the resultant panel in that particular direction.

The layers are allowed to cure for a period of from 3) hours to overnight. The rate of cure is dependent on the proportions of catalyst and accelerator in the mixture. Where pigment c is used, the faster the layers are cured, the darker the resultant colour.

The moulding is then removed from the mould and trimmed as required.

1 () Where required, additional components may be Incorporated partly or completely in the alternate layers of glass inat and back-up resin. For example, reinforcing stainless steel members may be buried in the layers for reinforcement. Alternatively, or in addition, fittings may be partially inserted in the panels for subsequently fixing panels in place. In a particular 5 use of the panels in fire safes and fire doors, door furniture, such as locks and hinges, may be partially or completely located in the moulding panel.

When using pigment, the resultant moulding is coloured all the way through. This 1 means that scratches are not permanently defacing as with painted phenolic panels. Although scratches first appear white, because some fire retardant powder is released, with polishing 10 cream the surface is wetted and scaled so that the scratch is substantially removed. In the case of coloured panels this is best achieved with a polishing cream containing the same pigment as 1 the panel. The most appropriate type of polish depends on the texture of the surface, for example, a silicone polish being suitable for a closs surface but not for a matt surface.

W A particular application of the panels of the invention is in the construction of 2-hour 15 fire doors, or thicker 4hour fire doors. The door panels may be manufactured incorporating all the required door furniture as discussed above. To li,ghten the weight of' a fire door while providing the required thickness, fire doors may he formed with moulded exterior panels and a core of non-con-ibustible standard lichtwel(-,ht partitioning material, such as calcium silicate, - - =1 rock wool or a mica composition.

20 Such doors have particular application in hospitals and hotels, beffic, considerably less expensive than traditional steel fire doors. Moreover, lightweight 4- 1i0Lir doors would be particularly applicable for upper stories of buildings, where the allowable floor loading will not support known heavy steel fire doors.

Similarly, it is possible to construct part itioiiiiit-) to create modular rooms, for example, 25 for open plan offices. Thus, effectively a large fire safe can be made in the form of a modular room with white or coloured panels and wood finish decorative panels. Such panels can be also be used for partitioning, roofs and ceilings.

Similarly, lightweight fire safes can be constructed from the panelling produced by the 1 n method of the invention, with partICUlar application on the upper stories of buildings with floor 30 loading limits too low to accommodate known heavier fire safes.

Claims (40)

1. A method of manufacturing glass-fibre-reinforced, low-smoke, fireretardant decorative mouldings comprising the steps of..

a) providing a mould having a mould surface, 5 b) providing a gel coating mixture suitable for forming a low-smoke, fire-retardant cure; c) applying the gel coating mixture to the mould surface to form a gel coat layer; d) curing the gel coat layer to form a low-smoke, fire-retardant presentation layer; e) providing glass fibre matting, 10 applying a layer of the glass fibre matting to the presentation layer; g) providing a back-up resin mixture for forming a low-smoke, fire- retardant cure; h) applying a layer of the back-up resin mixture to the layer of glass fibre matting; i) applying further alternate layers of glass fibre and back-up resin mixture to form a pre-determined thickness of layered material, 15 j) curing the back-up resin mixture of the layered material to form a low-smoke, fire retardant moulding; k) removing the moulding from the mould.

2. A method as claimed in claim 1, wherein step a) includes the step of..

al) providing a mould with any of a polished, matt and textured mould surface.

20

3. A method as claimed in claims 1 or 2, wherein step b) includes the steps of bl) mixing a polyester resin, an accelerator, and a wetting agent to form a mixture; b2) adding sufficient thixotropic material to raise the viscosity of the mixture to a predetermined viscosity value; b3) gradually adding fire-retardant filling powder and thoroughly mixing into the 25 mixture; and M) mixing in a curing catalyst to provide the gel coating mixture.

4. A method as claimed in claim 3, wherein step b 1) comprises mixing in the ratios 6 kg polyester resin: 60 mI -100 mI accelerator: 40 ml - 90 mI wetting agent.

5. A method as claimed in claim 4 wherein step b I) comprises mixing in the ratios of

6 kg 30 polyester resin: 90 ml accelerator: 40 mI wetting agent 1.4 6. A method as claimed in any of claims 3 to 5, wherein step bl) comprises mixing a pigment with the polyester resin, accelerator and wetting agent.

7. A method as claimed in claim 6, wherein step b 1) comprises mixing in the ratios 6 kg polyester resin: 60 mI - 100 mI accelerator: 40 ml - 90 ml wetting agent: 150 cc - 5 400 cc of pigment.

8. A method as claimed in claim 7, wherein step bl) comprises mixing in the ratios of 6 kg polyester resin: 90 ml accelerator: 40 mI wetting agent.. 300 cc pigment

9. A method as claimed in any of claims 3 to 8, wherein step b) includes measuring the viscosity of the resin using a viscosity pot test before mixing, and step b2) comprises.

10 adding predetermined quantities of thixotropic material dependant on the measured viscosity to raise the viscosity to the predetermined viscosity value.

10. A method as claimed in claim 9, wherein 100 cc of thixotropic material are added for each second less than 15 seconds recorded in the viscosity pot test.

11. A method as claimed in any of claims 3 to 10, wherein step b3) includes adding fire 15 retardant filling powder to the resin mixture in the ratio 9 kg - 20 kg of filling powder 6 kg of resin.

12. A method as claimed in any of claims 3 to 10, wherein step b3) includes adding filling powder to the resin mixture in the ratio 3: 1 of powder to resin.

13. A method as claimed in any of claims 3 to 12, wherein the step of adding fire-retardant 20 filling powder comprises adding aluminium hydroxide.

14. A method as claimed in any of the preceding claims wherein step c) comprises spraying a layer of the gel coating mixture substantially 0.5 mm thick onto the mould surface.

15. A method as claimed in any of the preceding claims, wherein step d) comprises curing the gel coat layer at room temperature for between 30 minutes and 3 hours.

25

16. A method as claimed in any of the preceding claims, wherein step e) comprises the step of providing woven glass matting or chopped strand glass matting and the step of cutting the matting to fit the shape of the mould.

17. A method as claimed in claim 16, wherein providing chopped strand glass matting comprises providing 300 gm/m 2 chopped strand glass matting.

18. A method as claimed in any of the preceding claims, wherein step e) includes providing glass fibre tissue and step 0 comprises applying a first layer of the glass fibre tissue and back-up resin to the presentation layer to strengthen the gel layer and prevent the subsequent penetration of the gel layer by coarse glass fibres.

19. A method as claimed in claim 18, wherein providing a glass fibre tissue comprises providing a printed or patterned glass fibre tissue.

20. A method as claimed in any of claims 3 to 19, wherein step g) comprises providing a back-up mixture in the same ratios as provided for the gel coating mixture in step b) but omitting the thixotropic material.

21. A method as claimed in any of the preceding claims, wherein step h) comprises brushing the back-up resin mixture into and over the layer of glass fibre matting.

22. A method as claimed in claim 21, wherein brushing the back-up resin mixture into and over the layer of glass fibre matting forms a layer of glass fibre matting and back-up resin substantially 1 min thick.

23. A method as claimed in any of the preceding claims, wherein step i) comprises applying different numbers of alternate layers in different portions of the mould to form different predetermined thickness in the different portions of the mould.

24. A method as claimed in any of the preceding claims, wherein step i) comprises incorporating fixing means at least partially between the alternate layers of glass fibre and back-up resin.

25. A method as claimed in any of the preceding claims, wherein step 1) comprises incorporating door furniture means at least partially between the alternate layers of glass fibre and back-up resin.

14

26. A method as claimed in any of the preceding claims, wherein step 1) comprises incor-porating reinforcing means at least partially between alternate layers of glass fibre and back-up resin.

27. A method as claimed in any of the preceding claims, wherein step j) comprises curing 5 the back-up resin mixture for over 3 hours at room temperature.

28. A method as claimed in claim 27, wherein curing the back-up resin mixture comprises curing the back-up resin mixture overnight.

29. Use of a moulding produced by the method of any of claims I to 28 for the fabrication of a fire-retardant enclosure, 10

30. Use of a moulding as claimed in claim 29, for fabrication of a fire safe.

31. Use of a moulding as claimed in claim 29 for fabrication of room partitioning for constructing a fire-retardant room.

32. A fire-retardant enclosure fabricated from a moulding produced by the method of any of claims I to 28.

15

33. Use of a moulding produced by the method of any of claims I to 28 for the fabrication of a fire door.

34. Use of a moulding as claimed by claim 33 for the fabrication of a fire door having at least one exterior panel moulding produced by the method of any of claims I to 28 and a core of a non-combustible material having a lower density than the moulding.

20 35, A fire door having at least one exterior panel of a moulding produced by the method of any of claims I to 28 and a core of a non-combustible material having a lower density than the moulding.

36 A fire door as claimed in claim 3 5, wherein the non-combustible material of the core is any one of calcium silicate, rock wool and mica.

25

37. A method substantially as hereiribefore described with reference to and as illustrated in the accompanying drawings.

38. A use of a moulding substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

39. A fire door substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

5

40. A fire-retardant enclosure substantially as hereinbefore descfibed with reference to and as illustrated in the accompanying drawings.