EP0526008A2

EP0526008A2 - Frameworks for fire-resistant doors and screens, and assembly for mounting fire-resistant panels

Info

Publication number: EP0526008A2
Application number: EP92306203A
Authority: EP
Inventors: Robert Henry Barrs; Jeffrey Robert Skeggs; Kevin Donald Shirley Towler
Original assignee: BRIGGS AMASCO Ltd
Current assignee: BRIGGS AMASCO Ltd
Priority date: 1991-07-04
Filing date: 1992-07-06
Publication date: 1993-02-03
Also published as: EP0526008A3; GB9114491D0; GB2258682A

Abstract

A framework for a fire-resistant door or screen comprises structural members of steel tube 10 on which panels 12 are mounted. The tube contains heat absorbing material 22 for absorbing heat from the framework, if the framework becomes hot in the event of a fire.

Description

This invention relates to improvements in framework systems for glazed fire-resistant screens or doors, and to an assembly for mounting fire-resistant panels on frames.
A known framework for a fire resistant screen system is made up from steel tubing of square cross section. Panels, such as glazing panels, are mounted on the steel tubes.
In one particular construction, one of the walls of the tubing extends out beyond the adjacent walls to form a lip. A frame for a door or screen is constructed from such tubes so that the lips and adjacent walls form a rebate for receiving the glazing panel. The edge of the glazing panel is held between the lip and a metal strip which overlaps the side of the tube. The strip is secured to the tube by screws and spaced from it by a layer of insulating material. The insulating material forms a thermal barrier to help reduce the amount of heat that would be transmitted through the frame from one side to the other in the event of a fire.
The present invention has been devised with the aim of improving the fire endurance and fire resistant properties of fire-rated screens, doors and glazing systems.
In a first aspect, the invention provides a framework for a fire-resistant door or screen, the framework being constructed from steel tube on which a panel for the door or screen can be mounted using mounting means, and the tube containing heat absorbing material for absorbing heat from the framework if the framework becomes hot in the event of a fire.
With this arrangment, the heat absorbing material can absorb heat from the steel tube, and thereby reduce the amount of heat which would be transmitted through the frame in the event of a fire.
Preferably, the heat abosrbing material is also a heat insulating material so that the material forms an insulating barrier inside the steel tube, and does not contribute significantly to heat conduction through the frame, even if the material becomes hot.
Preferably, the opposite side surfaces of the tube are covered with protective heat insulating material, arranged on either side of the frame. The insulating material forms a barrier to shield the tube from direct exposure to heat from a fire. In certain situations, the insulating material might be provided only for one side of the frame, however, it is generally preferred that the insulating material be used on both sides.
In a particularly preferred construction, the steel tubes are used as a core for the framework. The tubes are shielded on opposite sides by heat insulating material, as described above, and pairs of mounting members for mounting a glazing panel are secured outside the insulating material, on either side of the frame member. A decorative cover of aluminium cladding is secured over the mounting members.
The heat absorbent material may, for example, be plaster preferably the type commonly used in the manufacture of plasterboard. It is preferable that the material has a relatively high specific heat capacity. It is also preferable that the material be non-combustible.
Preferably the heat absorbing material substantially fills the interior volume of the tube, and is in direct contact with the inner surface of the tube. This ensures tha the heat absorbing material is in good thermal contact with the tube.
The heat absorbent material may be put in the tubes during manufacture, or during preparation of the tubes for use in the frame, or it may be put in the tubes during asembly of the framework system. When plaster is used as the heat absorbing material, one method of introducing the plaster is to inject wet plaster into the tube, and allow the plaster to set, prior to assembly of the framework system. An alternative method is to insert strips or pieces of plasterboard into the tubing.
Therefore, in a second aspect the invention provides a frame member for constructing a framework for a fire resistant door or screen, the frame member comprising steel tube on which a panel for the door or screen can be mounted using mounting means, and heat absorbing material inside the tube, the arrangment being such that, in use, in the event of a fire the heat absorbing material can absorb heat from the tube if the tube becomes hot.
In another aspect the invention is directed to an improved system for mounting glazing panels to construct a fire-resistant door or screen.
In this aspect, the invention provides a glazed fire-resistant door or screen comprising a glazing panel mounted in a frame of steel tube, the edges of the panel being held by mounting means which are secured to the tube and which grip the faces of the panel near or at its edges, the mounting means including at least one mounting member having a channel-shaped portion which fits over one side of the tube and a flange portion which overlaps the edge of the panel, the mounting member being secured to the tube by fixing means, and being thermally insulated from the tube by heat insulating material between the tube and the mounting member.
Such an arrangement can offer an advantage over the particular known arrangement described above, because it enables a tube to be used which is significantly deeper, as measured from the front of the frame to the rear, than the thickness of the glazing panel. With the known arrangement, if such a tube were to be used, a large amount of packing material would be required between the glazing and the strip or the lip in order to hold the glazing firmly.
With the present invention, the flange portion of the mounting member is not restricted to being outside the plane of the wall of the tubing, as with the conventional mounting strip. By suitable design of the mounting member the flange can be arranged to be close to the surface of the glazing, even if large dimension tubing is used.
Preferably the mounting member is in the form of a strip which fits along an entire edge of the panel. This provides good support for the edge of the panel along its entire length.
Preferably, the insulating material is bonded to the inner surface or surfaces of the channel portion of the mounting member which are adjacent the tube. This simplifies attachment of the mounting member on the tubing during assembly of the frame.
A suitable insulating material is Micropore insulation, and typically a layer 5mm thick may be used.
Preferably, the mounting member has a second flange portion which extends away from the channel portion in the opposite direction to the aforementioned flange portion, such that the mounting member has a hat-shape profile. Such a mounting member is suitable for mounting two glazing panels, one on each side of, or one above and one below, the tubing.
Preferably, the mounting means also include a second mounting member identical to the aforementioned mounting member. The mounting members are attached to the tube in opposed relation to each other. The edge of the glazing panel is held between the opposed flange portions of the mounting members. Strips of compressible material may be arranged between the flange portions and the surface of the glazing panel so as to increase the gripping pressure on the panel.
In a fourth aspect, the invention also provides components for a fire-resistant door or screen including a steel tube, a glazing pandel and a mounting member for mounting the glazing panel in a frame constructed from the steel tube frame, the mounting member having a channel-shaped portion adapted to match the profile of the steel tube such that the channel-shaped portion can fit over one side of the tube, and a flange portion for overlapping the edge of the glazing panel to be mounted, the inner surface or surfaces of the channel shaped portion being covered with heat insulating material to thermally insulate the mounting member from the tube when assembled, and the mounting member being securable to the tube by fixing means.
Embodiments of the inventionwill now be described by way of example, with reference to the accompanying drawings, in which:

fig. 1 is a sectional view through the edge region of a fire resistant screen;
fig. 2 is a partial perspective view of an alternative framework system for a fire resistant screen;
fig. 3 is a sectional view along the line III-III of fig. 2;
fig. 4 is a sectional view along the line IV-IV of fig. 2; and
fig. 5 is a diagramatic perspective view showing how the mounting members are arranged.

Referring to figure 1, this shows a cross-section through a part of a glazed fire-resistant screen or door in accordance with the invention. The framework of the screen is made up of rectangular section steel tubing 10. Steel is used to give the structure the necessary strength and integrity in the event of a fire, and in the present example, square section tubing is used. A glazing panel 12 is mounted at its edge portion 14 on the tubing 10 by two strips of stop beading 16 and 18 secured to one side of the tubing. The glazing panel may be made, for example, of Pyran, Pyrostop, Pyrobel, Pyroswiss or of Georgian Wire Polished Plate. The strips of beading 16 and 18 are positioned one on each side of the panel to hold the edge of the panel in position. A layer of compressible material 20 is placed between the glazing panel 12 and each strip 16, 18 so that the strips firmly grip the glazing panel 12. the strips 16 and 18 can be secured to the steel tubing 10 by conventional means such as screws, clips, studs or rivets.
The interior of the tubing 10 is substantially filled with a heat absorbing material 22. In the present example, plaster is used as the heat absorbing material 22. The plaster can be injected into the tubing 10 through one end prior to assembly of the framework, and allowed to set hard. The plaster 22 makes direct contact with interior surfaces of the tubing so that it is in good thermal contact with the tubing 10.
In use, in the event of a fire, the fire-resistant screen should form an effective barrier to the passage of smoke, flames and heat. The heat absorbing material 22 helps to reduce the amount of heat transmitted through the framework by absorbing heat directly from the steel tubing. Although in the event of a serious fire, the heat absorbing material will not be able to absorb all of the heat in the frame, it can slow down the rate at which the overall frame gets hotter, thereby improving the fire-resistant properties of the screen or door.
It is preferred that the heat absorbing material has a relatively high specific heat capacity so that the material can absorb a fairly large amount of heat energy without becoming too hot. It is aso preferred that the heat absorbing material be non-combustible so that it will not catch fire inside the frame, even if the frame becomes very hot.
Figure 2 shows a partial view from one side of an alternative construction of framework system. The part of the framework shown is a T-junction between two horizontal frame members 30 and 32 running along a floor and a vertical frame member 34. Two glazing panels 36 and 38 are mounted in the framework on opposite sides of the vertical frame member 34.
Referring to figure 3, the vertical frame member 34 is made up of a tubular steel core 40 of rectangular section. The core 40 is typically 60mm deep from one side of the framework to the other (ie. front to rear), and 30mm wide. The inside of the core is substantially filled with a heat absorbing material 41, such as plaster as described hereinbefore.
The glazing panels 36 and 38 are held in position by a pair of mounting members in the form of bracket strips 42 and 44 which are secured to the front and back of the steel core 40. Each bracket 42, 44 has a central rectangular channel shaped portion 46 which is shaped to match fit around the front or rear face of the core 40, and two flange portions 48a and 48b which extend in opposite directions away from the channel portion 46 to give the bracket and overall "hat shape" profile. The brackets 42 and 44 are made of mild steel.
A thin layer of heat insulating material 50 is arranged between the adjacent walls of the core 40 and each bracket 42, 44. A suitable material is Micropore insulation, and the thickness may be around 5mm. The insulation material 50 may conveniently be bonded to the inner surfaces of the channel portion 46 of each bracket 42, 44 prior to assembly of the framework system so that the bracket 42 is simple to fit on to the core 40.
Each bracket 42, 44 is secured to the steel core 40 by means of screws 52 at intervals along the length of the bracket 42, 44. The screws pass through holes in the channel portion 46 of the bracket and through the wall of the steel core 40.
The flange portions 48a of the two brackets 42 and 44 overlap the edge of one glazing panel 36 to hold it in position as described in more detail below. The other flange portions 48b of the two brackets 42 and 44 overlap the edge of the other glazing panel 38 similarly to hold it in position.
A cladding 56 of extruded aluminium or steel is fitted around each bracket 42, 44. The cladding is generally of C-shaped section, the end walls 58 of which turn-in towards each other to fit between the flange portions 48a and 48b of the respective bracket 42, 44 and the glazing panels 36 and 38.
The wall of the cladding 56 remote from the glazing is formed with a central channel 60 which has a rebate 62 in each side wall of the channel adjacent the web 66 of the channel. Holes 68 are formed in the web 66 at the positions of the screws 52 to accomodate the heads of the screws 52. The diameter of the holes 68 is larger than the diameter of the screw heads so that the screws can be tightened against the brackets 42, 44. The channel 60 in the cladding 56 allows access to the screws during assembly of the framework.
The channel 60 in the rebate is covered after assembly by means of a longitudinal channel shaped cap 74 which forms a snap-fit in the channel 60. The cap 74 has outwardly biased side walls 76 with barb-shaped ends 78. The barb-shaped ends 78 locate in the rebates 62 in the channel 60 to hold the cap 74 in position once fitted. The surface of the cap 74 lies below the surface of the claddding 56 for decorative effect.
The cladding 56 is held in position by the end walls 58 located between the brackets 42, 48 and the glazing panels 36, 38.
Locating ridges 70 and 72 are formed on the inside of the cladding 56 to locate the cladding 56 relative to the respective bracket 42, 44. The cladding 56 is fitted to the bracket by sliding the bracket in through one end of the cladding 56 before the assembly is secured to the steel core.
The cladding provides a decorative finish to the framework and protects the structure during normal use. To mount the glazing, the cladding 56 and bracket 42 assembly for one side of the frame is secured to the core 40 using the screws 52, and the glazing panels 36 and 38 are positioned. The other bracket 44 and cladding 56 assembly is then secured to the core using the screws 52.
A strip 80 of compressible material may be arranged between the faces of the glazing panels 36 and 38 and the ends 58 of the cladding 56, so as to improve the grip on the panels. A rubber sealing gasket 82 may also be fitted to seal the gap between the each panel 36, 38 and the cladding 56. In the present example, the sealing gasket 82 is formed with a ridge 84 which is of mushroom-head section. The gasket 82 is fitted by pressing the ridge 84 into a longitudinal rebate 86 formed in the cladding 56.
As the screws 52 are tightened, the flange portions 48a and 48b of the brackets 42 and 44 act as pressure plates to apply compresive pressure through the end walls 58 of the cladding 56 and through the strips of compressible material 80 to grip the edges of the panels 36 and 38.
Referring to fig. 4, the construction of the horizontal frame members 30 and 32 is very similar to that of the vertical frame member 34. The horizontal member has a steel core 100 which is identical to core 40 in the vertical member, and a pair of mounting brackets 102, 104 with insulating material 105 secured on opposite sides of the core 100. The brackets 102 and 104 are identical to the brackets 42 and 44 described above, except at the ends where there are minor differences as described below. Cladding 106 is fitted around each bracket 102, 104 in the same fashion as the cladding 56, and the structure supports the glazing panels 36 (and 38) in the same way as the vertical frame member. The core 100 is substantially filled with a heat absorbing material, such as plaster, in a similar fashion to the core 40.
A block of non-combustible material 108 is fitted between the edge of the panel 36 and the core 100 to help support the lower edge of the panel. In the present example, the block 108 comprises a 5mm thick section of Tacfire Board.
The design of the cladding 106 differs slightly from the design of the previous cladding 56 described earlier in that the cladding 106 does not stand as proud of the glazing panels 36 and 38 as the previous cladding 56. The corresponding channel 60′ in the cladding 106 is shallower than the channel channel 60 in the previous cladding 56 such that the surface of the cap 74′ in the channel 60′ is flush with the surface of the cladding 106.
The cavity 110 in the lower side of the horizontal frame members 30 and 32 is filled with a fire-resistant packing material 111 such as Cerablanket. There may be a small gap between the floor and the lower surfaces of the cladding 106′, and this can be sealed using a suitable fire resistant sealant 109 such as Nullifire M701.
The horizontal frame members 30 and 32 are supported by a spigot-and-socket type connection (not shown) with the vertical frame member 34. The connection joins the steel cores of the frame members.
The vertical member 34 is secured to the floor by means of a U-shaped floor bracket 112 shown phantom in figures 3 and 4. The base of the bracket 112 is bolted to the floor, and the side walls 114 fit inside the steel core 40 of the vertical frame member 34. A hole is formed in each side wall 114 in register with the position of the lowermost securing screws 52 in the vertical frame member (the position being shown in fig. 5 and by the phantom circle 116 in fig. 2). The lowermost screws 52 engage in the floor bracket 112 to secure the vertical frame member 34.
Figure 5 illustrates how the mounting bracket 40 for the vertical frame member 34 co-operates with mounting bracket 102 of the horizontal frame member 30 at the T-junction. The lower end 120 of the vertical bracket 40 is cut away in a step shape 122 in each flange portion 48, and in a step shape 124 in the sides of the channel portion 46 to match the profile of the horizontal mounting bracket 102. When the brackets 40 and 102 are secured to the respective cores 40 and 100, the brackets meet to form a continuous covering over the cores 40 and 100, and the flange portions together form a continuous flange to apply pressure to the glazing panel (36) all of the way around the corner region.
The junction between the mounting brackets 42 and 104 of the vertical and horizontal frame members 34 and 30 on the opposite side of the frame is identical, and the respective mounting brackets for the other horizontal frame member 32 form a similar connection with the brackets 40 and 42 of the vertical frame member.
In the event of a serious fire, the cladding 56, 106 may burn or melt away, however, the mild steel mounting brackets will keep their strength and integrity to hold the glazing panels in position in the frame.
The insulation material 50 and 105 between the steel cores 40 and 100 and the brackets 40, 42 and 102, 104, respectibely, thermally insulates the cores from the brackets. Therefore, even if the cladding on one, or both, sides of the framework is burnt away and the brackets become hot, only a small proportion of the heat will be transmitted to the cores of the framework. The heat absorbing material in the cores can absorb heat directly from the core tubing, and this helps to keep the cores cool. In particular, if a fire is burning on only one side of the screen, the two layers of insulating material and the heat abosorbing material in the core help to reduce the amount of heat that will be transmitted through the framework to the other side.
The hat-shape profile of the mounting brackets 40, 42 and 102, 104 enables the core tubing to be considerably deeper than the glazing panels without requiring a large amount of packing material to grip the glazing panel on each face. In the present embodiment the steel core is roughly twice as deep as the glazing panel.
The advantage of being able to use fairly deep core tubing is that the width of the tubing as viewed from the front or rear of the framework can be relatively small without comprising the strengh of the frame. The strength of the core tubing will depend on the cross-sectional area of the tubing, since this determins the amount of metal used. A framework using such 'thin' rectangular cores can appear to be less bulky, and more asthetically pleasing than an equivalent design using square section tubing.
It will be appreciated that with the embodiment shown in figs 2 to 5 it is fairly easy to assemble the framework to construct a fire-resistant screen. The plaster used as the heat absorbing material can be injected into the core tubing during manufacture, or prior to assembly of the framework, and allowed to set hard.
The steel core tubing can be stock tubing, and the mounting brackets can be rolled from mild steel. As explained hereinbefore, it is preferred that the insulating material be bonded to the mounting brackets so that they are simple to fit on to the steel cores.
The framework may also include horizontal frame members which support glazing panels both above and below the frame member. The construction of these frame members may be similar to that shown in fig. 5 except that the Cerablanket packing material 111 and the sealant 109 on the lower side of the frame will be replaced by the edge of a glazing panel and associated components, ie. compressible strips 80′ and sealing gaskets 82′ as for the glazing on the upperside of the frame. The horizontal frame member will thus grip the edges of two panels, in a similar fashion to the vertical frame member shown in fig. 3.
Similarly, the construction of vertical frame members at the edge of the fire screen adjacent, for example, a wall will be similar to that of fig. 3 except that one of the glazing panels will be replaced by packing material and sealant, as shown for the horizontal frame member in fig. 4.
Although in the embodiment shown in figs. 2 to 5 the cladding 56 and 106 is held by the flange portions of the mounting brackets 42, 44 and 102, 104, in an alternative embodiment the cladding may be secured by means of the screws 52 which attach the mounting brackets to the steel cores. The end walls 58 of the cladding may then be omitted, so that the cladding a more U-shaped section.
Although in the embodiment shown in figs. 2 to 5, a pair of identical mounting brackets are secured to the core in opposed relation to each other, in an alternative embodiment only a single mounting bracket might be used. The frame structure would then need to include some other means to abutt the glazing panel to replace the omitted bracket. Such means might, for example, comprise a beading strip or a lip formed in the core.
Although in the embodiment shown in figs. 2 to 5, the cores of the frame members have been filled with heat absorbing material, the same construction may also be used without the heat absorbing material. The insulating material between the brackets and the cores will still provide a thermal barrier to reduce the amount of heat that can be transmitted from one side of the framework to the other, and to slow down the rate at which the core would be heated up.
It will, of course, be appreciated that the best performance of the fire-rated screen will be provided when both aspects of the invention are used together.

Claims

A framework for a fire-resistant door or screen, the framework being constructed from steel tube on which a panel for the door or screen can be mounted using mounting means, and the tube containing heat absorbing material for absorbing heat from the framework if the framework becomes hot in the event of a fire.
A framework according to claim 1, wherein the heat absorbing material substantially fills the interior volume of the tube.
A framework according to claim 1 or 2, wherein the heat absorbing material is in direct contact with the interior faces of the tube so as to make good thermal contact with the tube.
A framework according to claim 1, 2 or 3, wherein the heat absorbing material has a relatively high specific heat capacity.
A framework according to claim 1, 2, 3 or 4, wherein the heat absorbing material is non-combustible.
A framework according to any of claims 1 to 5, wherein the heat absorbing material is a thermal insulating material.
A framework according to any of claims 1 to 6, wherein the heat absorbing material is plaster.
A framework according to any of claims 1 to 7, wherein the heat absorbing material is injected into the tube.
A framework according to any of claims 1 to 8, wherein the heat absorbing material is put into the tube prior to assembly of the framework.
A framework according to any of claims 1 to 9, wherein the heat absorbing material substantially fills all of the steel tube in the framework.
A framework according to any of claims 1 to 10, wherein protective heat insulation material is arranged adjacent the exterior of the steel tubing.
A framework according to claim 11, wherein the mounting means comprise brackets securable to the tube outside the protective heat insulation material.
A frame member for constructing a framework for a fire-resistant door or screen, the frame member comprising steel tube on which a panel for the door or screen can be mounted using mounting means, and heat absorbing material inside the tube, the arrangement being such that, in use, in the event of a fire the heat absorbing material can absorb heat from the tube if the tube becomes hot.
A frame member according to claim 13, wherein the heat absorbing material substantially fills the interior volume of the tube.
A frame member according to claim 13 or 14, wherein the heat absorbing material is in direct contact with the interior faces of the tube so as to make good thermal contact with the tube.
A frame member according to claim 13, 14 or 15, wherein the heat absorbing material has a relatively high specific heat capacity.
A frame member according to claim 13, 14, 15 or 16, wherein the heat absorbing material is non-combustible.
A frame member according to any of claims 13 to 17, wherein the heat absorbing material is a thermal insulating material.
A frame member according to any of claims 13 to 18, wherein the heat absorbing material is plaster.
A frame member according to any of claims 13 to 19, wherein the heat absorbing material is injected into the tube.
A glazed fire-resistant door or screen comprising a glazing panel mounted in a frame of steel tube, the edges of the panel being held by mounting means which are secured to the tube and which grip the faces of the panel near or at its edges, the mounting means including at least one mounting member having a channel-shaped portion which fits over one side of the tube and a flange portion which overlaps the edge of the panel, the mounting member being secured to the tube by fixing means, and being thermally insulated from the tube by heat insulating material between the tube and the mounting member.
A door or screen according to claim 21, wherein the mounting member is in the form of a strip filling along the whole length of the edge of the glazing panel.
A door or screen according to claim 21 or 22, wherein the depth of the tube from the front of the frame to the rear is substantially greater than the thickness of the glazing panel.
A door or screen according to claim 23, wherein the depth of the tube is substantially greater than its lateral dimension.
A door or screen according to claim 21, 22, 23 or 24, wherein the tube is of substantially rectangular cross section, and the channel-shaped portion of the mounting member is of substantially U-shaped cross section.
A door or screen according to any of claims 21 to 25, wherein the insulating material is bonded to the surface or surfaces of the channel portion of the mounting member adjacent the tube.
A door or screen according to any of claims 21 to 26, wherein the insulating material comprises Micropore insulation material.
A door or screen according to any of claims 21 to 27, wherein the thickness of the insulation matreial is around 5mm.
A door or screen according to any of claims 21 to 28, wherein the mounting member has a second flange portion extending away from the channel portion in the oposite direction to the aforementioned flange portion, such that the mounting member has a substantially hat-shape profile.
A door or screen according to any of claims 21 to 28, wherein the fixing means comprise screws.
A door or screen according to any of claims 21 to 30, wherein the mounting member is made of mild steel.
A door or screen according to any of claims 21 to 31, further comprising a cladding fitting over the mounting member.
A door or screen according to claim 32, wherein a wall of the cladding remote from the galzing is formed with a recessed channel, the web of the channel being close to a surface of the mounting member, and the web being formed with holes for accommodating the fixing means.
A door or screen according to claim 33, wherein a longitudinal cap fits in the mouth of the channel in the cladding when the frame is in the assembled condition, the cap being a snap fit in the channel.
A door or screen according to any of claims 21 to 34, wherein the mounting means includes a second mounting member identical to the aforementioned mounting member, and secured to the tube in opposed relation to the aforementioned mounting member.
A door or screen according to claim 35, wherein the edge of the glazing panel is clamped between the opposed flange portions of the mounting members.
A door or screen according to claim 36, wherein strips of compressible material are arranged between the glazing panel and the opposed flange portions of the mounting brackets.
A set of components for a fire-resistant door or screen including a steel tube, a glazing panel and a mounting member for mounting the glazing panel in a frame constructed from the steel tube, the mounting member having a channel-shaped portion adapted to match the profile of the steel tube such that the channel-shaped portion can fit over one side of the tube, and a flange portion for overlapping the edge of the glazing panel to be mounted, the inner surface or surfaces of the channel-shaped portion being covered with heat insulating material to thermally insulate the mounting member from the tube when assmbled, and the mounting member being securable to the tube by fixing means.
A mounting member according to claim 38, wherein the mounting member includes a second flange portion for overlapping the edge of a second glazing panel, the second flange portion extending away from the channel portion in the opposite direction to the aforementioned flange portion, such that the mounting member has a substantially hat-shaped profile.
A mounting member according to claim 38 or 39, wherein the heat insulating material is bonded to the mounting member.
A mounting member according to any of claims 38 to 40, the mounting member being in the form of a strip for mounting along the length of the edge of the glazing panel to be mounted.
A mounting member according to any of claims 38 to 41 made of mild steel.
A mounting member according to any of claims 38 to 42 wherein the channel portion has a substantially U-shaped cross section.