GB2442733A

GB2442733A - Fire resistant frame assembly and fire door

Info

Publication number: GB2442733A
Application number: GB0620142A
Authority: GB
Inventors: Andrew Gailey; Richard Coulson
Original assignee: Graham Holmes Astraseal Ltd
Current assignee: Graham Holmes Astraseal Ltd
Priority date: 2006-10-11
Filing date: 2006-10-11
Publication date: 2008-04-16
Also published as: GB0620142D0

Abstract

A fire resistant frame assembly 32 comprises at least two structural frame members 32a, 32b of heat meltable material, at least two rigid non-combustible reinforcing members 50a, 50b, and a fixing bracket 54a secured to an end of at least one of the reinforcing members by spot-welding 58. One of the frame members may be fastened to the fixing bracket by a mechanical fastener 52. Intumescent material (not shown) may be provided internally of the frame members. The frame members may be of PVC-U and the reinforcing members of galvanised steel. The assembly may comprise a door (40, Fig. 3C) having a profiled section (44, Fig. 3B) being shaped to receive a strip of intumescent material (60, Fig. 3B). The frame assembly may further comprise a corner post (18, Fig. 4A) affixed to two adjacent frame members (30b, 30c, Fig. 4A), with intumescent material (60c, 60d, Fig. 4A) disposed between the corner post member and each frame member.

Description

Improvements to Fire Retardant Systems

Field of the invention

The invention relates to methods of manufacture of fire doors, fire screens coupled to fire doors and the fire doors, fire screens coupled to fire doors and fixings therefor.

More particularly but not exclusively the invention relates to a method of manufacturing a composite fire retardant door and side screen system comprising heat

meltable material.

Background of the invention

The British Standard, BS 476 Part 22 1987 stipulates that window and door assemblies to be used on fire escape routes must achieve a 30 minute fire rating at a temperature of around 800 C.

Structural frame members for doors, windows and screens are commonly extruded from heat meltable material such as plastics, in particular polyvinylchloride- : *.., unplastercised (PVC-u) or metals such as Aluminium. These materials, due to their I...

*. ... 20 melting temperature, typically do not meet the British safety standard. S..

In GB 2309728 a structural frame member which is formed of PVC and which can achieve the required 30 minute fire rating is disclosed. The GB 2309728 fire-frame uses an intumescent material disposed within cavities of the extruded heat-meltable : : 25 plastic to prevent fire breaking through the fire door and frame assembly within 30 S.....

* minutes. In addition, a steel or other rigid reinforcing member (28) is provided to support the extruded frame member. The intumescent strips are configured deliberately to provide support to the assembly when the frame extrusion starts to melt at temperatures around 80-100 C.

It is important in such fire rated systems that there are no fire-breaks i.e. gaps through which the fire could leak', if this occurs the system will fail. In addition as the intumescent material expands (usually at temperatures of 100-150 C) it is desirable that the pressure imparted onto the door or window assembly does not cause a structural physical failing of the door or window assembly. It is desirable that such assemblies can be manufactured, consistently, efficiently and safely. Furthermore it is desirable that the intumescent material, where not disposed entirely internally of the structural frame members does not become damaged during normal everyday use. If such damage occurs then at the outbreak of fire, the intumescent material may fail and as a result the whole fire-retardant system would be vulnerable to fail.

The present invention seeks to provide improvements in the manufacture and fitting of window, door and side-screen assemblies meeting the 30 minute British Standard rating.

Summary of the Invention

15.According to a first aspect, the invention provides a method of manufacturing a fire resistant frame assembly comprising: providing at least two extruded structural frame members of heat meltable material; providing at least two rigid non-combustible reinforcing members; securing a fixing bracket to an end of one or both of the rigid : ** non-combustible reinforcing members by spot-welding; inserting each of said rigid non-combustible reinforcing members, into one of each of the extruded structural frame members; and fixing said extruded structural frame members together using a mechanical fixing. * *

Preferably said method comprises providing intumescent material internally of the : 25 extruded structural frame members. Preferably wherein the rigid non-combustible ****** * reinforcing members are each formed from galvanised steel.

According to a second aspect, the invention provides a fire resistant frame assembly comprising a joined pair of heat meltable structural frame members, each heat meltable structural frame member having a rigid non-combustible reinforcing member disposed therein, one of said rigid non-combustible reinforcing members being joined by spot-welding to a fixing bracket and one of said heat meltable structural frame members being mechanically fastened to said fixing bracket.

Preferably the fire resistant frame assembly comprises a door having along a bottom edge thereof a profiled section for receiving a strip of intumescent material.

Optionally the profiled section is shaped to receive a strip of intumescent material and securely hold said strip of intumescent material within the profiled section. Preferably the fire resistant frame assembly according to claim 7 wherein the profiled section is dovetail shaped.

Optionally the fire resistant frame assembly comprises a corner post member affixed to two adjacent heat meltable structural frame members in which intumescent material is disposed between the corner post member and each heat meltable structural frame member, and comprising a bracket for affixing said corner post member and said two structural frame members, the bracket being structured and arranged for maintaining the heat meltable structural frame members affixed to the corner post when the intumescent material expands. Optionally the bracket comprises a spigot inserted into a channelled reinforcement of the corner post member and two arm portions extending from said spigot each being fixed to one of the heat meltable structural frame members.

: ** Preferably the fire resistant frame assembly comprises an automatic door closer coupled between a hinge edge of the door and an adjacent door frame wherein I...

intumescent material is positioned at least in part around a potion of the automatic * :* door closer disposed within the hinge edge of the door and/or door frame.

I..... * .

* According to a further aspect, the invention provides a frame assembLy for an half- * : 25 hour fire door or screen comprising extruded PVC-u sections and galvanised steel *.*** * reinforcing sections, the frame comprising a joint, at which joint one of said galvanised steel reinforcing sections is adjoined to a fixing bracket by spot-welding and one of said PVC-u sections is mechanically fastened to said fixing bracket.

According to a further aspect, the invention provides an half-hour fire door having a profiled section formed in a bottom edge of the door, the profiled section being shaped such that a strip of intumescent material is receivable therein and retainable therein by virtue of the shaped profile. Preferably, the fire door comprises a PVC-u skin.

Optionally, the half-hour fire door comprises an automatic door closer coupled between a hinge edge of the door and an adjacent door frame wherein intumescent material is positioned at least in part around a potion of the automatic door closer disposed within the hinge edge of the door and/or door frame.

According to a further aspect, the invention provides a method of manufacturing a fire resistant frame assembly comprising: providing two extruded structural frame members of heat meltable material; providing intumescent material between one or both of said structural frame members and a corner post member; attaching each extruded structural frame member to a corner post member having a channel section; affixing each of said extruded structural frame members to the corner post member using a securing bracket the securing bracket being structured and arranged for maintaining the heat meltable structural frame members affixed to the corner post when the intumescent material expands.

Preferably in the method a securing bracket is disposed within a channelled section of the corner post member and further portions of the bracket extend along an edge of * ** each of said extruded frame members.

S.:.,. 20 S..

According to yet a further aspect of the invention, a bracket for affixing a corner post member to adjacent heat meltable structural frame members for a fire resistant S...

S:..: assembly in which intumescent material is disposed between the corner post member and each heat meltable structural frame member, the bracket being structured and : . 25 arranged for maintaining the heat meltable structural frame members affixed to the * :: corner post when the intumescent material expands.

Preferably the bracket comprises a spigot receivable in a channelled or reinforcement section of the corner post member and at least two ann portions, the angle between the two arm portions being similar to the angle between adjacent heat meltable structural frame members. Preferably, the angle between the two arm portions is adjustable. Optionally, each ann portion comprises a fixing aperture, the fixing aperture being configured to align with a fixing port of said structural frame member.

According to yet a further aspect, the invention provides a method of manufacturing a fire door comprising, routing an edge of the door into a profile for receiving a strip of intumescent material to be received and held therein.

Brief Description of the Drawings

An exemplary embodiment of the invention will now be described with reference to the accompanying drawings in which: Figure 1 illustrates a door frame, door and side screen corner assembly according to an exemplary embodiment of the invention; Figure 2A illustrates schematically a step in the process of forming a reinforced corner joint for the frame assembly of Figure 1; Figure 2B illustrates schematically an assembled corner joint of the frame assembly of Figure 1; * *. Figure 2C illustrates schematically a step in the process of forming a reinforced transom joint for the frame assembly of Figure 1; *.** * Figure 3A illustrates a perspective front edge and bottom view of a portion of a fire * : * door used in the assembly of figure 2 having a routed door edge for receiving a strip :. * of intumescent material; * 25 * : * Figure 3B illustrates a perspective front edge and bottom view of the door portion of Figure 3A with a portion of a strip of graphite material being inserted; Figure 3C illustrates schematically the door of Figures 3A & 3B being opened internally showing the intumescent strip housed therein; Figure 4A illustrates a cross-sectional view of the corner post frame assembly; and Figure 4B illustrates a perspective view of a fixing for the corner post of Figures 1 and4A.

Detailed Description of Exemplary Embodiment

The accompanying drawings, particularly Figure 1 thereof show a fire retardant system 100 according to a first embodiment of the present invention. The fire retardant system 100 is compliant with British Safety Standard 476 Parts 20 and 22 in that it provides an half-hour retardancy to the outbreak of fire preventing spread of fire and thereby mitigating fire damage and/or permitting escape from a building comprising the fire retardant system 100.

The fire retardant system 100 comprises a door 30 housed within a frame stn.icture 32.

Above the door 40, there is a panelled screen section 22c, the panelled screen section 22c is housed within frame structure 32 and further supported by a transom support 26e, as shown in Figure 1.

Adjoining the dOor frame 30 is a corner side screen assembly denoted by references 18, 20a, 20b, 20c, 20d, 30a, 30b, 30c and 30d. The corner side screen assembly comprises screen panels 20a, 20b, 20c, 20d each housed within an associated frame * ** structure 30a, 30b, 30c and 30d and supported by further transom supports 26a, 26b, 26c, 26d, 28a, 28b, 28c and 28d. The frame structures 30b and 30c are connected by a corner post member 18. Frame structures 32, 30a, 30b, 30c and 30d preferably are * formed from extruded polyvinyichioride-unpiastercised (PVC-u) reinforced with an internal supporting member 50 (shown in Figures 2A and 2B). Internal supporting *. 25 member 50 is a rigid member, formed from galvanised steel.

: : The corner post member 18 is attachable to both frame structures 30b and 30c as well as to an upper or lower building level such as a ceiling, roof or floor by a fixing member 80 as illustrated in Figure 4B.

The fire retardant system 100 may form an internal or external structure and as hereafter described comprises a number of features which enable the system to be manufactured consistently, efficiently and safely to provide an half-hour fire retardancy in compliance with British Safety Standard 476 Part 22 1987. Before such a system can be marketed it is first necessary to seek accreditation from an -7.-independent testing agency to prove compliance with the BSI 476 Part 22: 1987. In the case of the present invention, approval for this system has been obtained by Warrington Fire Global Safety Testing.

Accreditation by Warrington Fire Global Safety under BS 476 Part 22 can only be obtained if the fire-retardant assemblies, such as that in Figure 1, when rigorously tested, can withhold a fire for at least 30 minutes. If the fire can break through the assembly, the whole system will fail. Once accreditation has been obtained it is important during the industrial manufacturing process making such fire retardant systems that the component parts consistently are manufactured to the tested standard.

The manufacture of a portion of the frame structure 32 will now be described with reference to Figures 2A and 2B, it being understood that the manufacturing process is the same for frame structures 30a, 30b, 30c and 30d.

Two lengths of extruded PVC-u, 32b, 32a are provided. Each length of extruded PVC-u 32b, 32a is oppositely mitred to the other in order to achieve a required angle of joint. In this example, the frame structure 32 is of rectangular shape, requiring a : .**. right-angled joint and therefore each extrusion 32a, 32b is mitred at an angle of 450 I...

In frame manufacture for systems not requiring the half-hour fire retardancy a steel reinforcement strip is inserted within each portion of an extrusion to be joined but stops short of the mitred ends of the extrusion the two extruded lengths are then welded together by melting the PVC-u extrusions and holding them together at the required angle. Such a frame structure is not acceptable for systems requiring half-hour fire retardancy due to the gap between the steel reinforcement strips through * which the fire could break causing failure of the system. In newly developed half-hour retardant systems it is necessary to ensure that there is the gap between the steel reinforcements does not exceed 1.5mm. The present invention provides a method of forming a frame structure 32 which meets the half-hour fire standard, is safe and efficient to manufacture and which can be consistently manufactured thereby ensuring that all frame structures produced comply with BS 47 Part 22.

Turning now to Figure 2A, extruded PVC-u frame members 32a, 32b are mitred at an angle of 45 . Similarly, strips of internal supporting member 50a, SOb, which are formed from galvanised steel are also mitred at the required angle. "L"-shaped fixing brackets 54a, is secured only by spot-welding at a mitred end of one of the internal supporting members 50a. This technique does not provide a completely sealed joint between the "L"-shaped fixing bracket 54a and the internal supporting members 50a, with only a discrete number of spots 58 of the internal supporting members 50a and "L"-shaped fixing bracket 54a being welded together. Before welding of the mitred ends of the PVC-u frame members 32a, 32b is performed, the internal supporting members 50a, 50b are brought together. The internal supporting members 50a, 50b are fully inserted into the extruded PVC-u frame members 32a, 32b which are then brought together and the mitred ends fully welded together to provide a sealed joint 56. Additionally the joint is reinforced by using a mechanical fastener 52, such as a self-tapping screw which can be engaged though one of the extruded PVC-u frame members 32a and into both fixing brackets 54a, 54b. In this way a secure joint is made quickly and efficiently.

By only welding the bracket 54a to the galvanised steel internal supporting members SOa, at discrete spots 58, less welding of the galvanised steel is conducted than would otherwise be necessary if a fully welded sealed joint was created. Welding galvanized steel produces fumes, for example zinc vapour and zinc oxide, which may be hazardous to health and full welding takes a longer time compared to spot-welding.

By spot-welding the joint is beneficial in that it is quicker and less hazardous to : produce yet beneficially remains secure enough not to allow fire to break through; * 25 testing by Warrington Fire Global Safety was necessary to confirm this.

*.*.** * . The method described above is equally applicable for the transom support member 28c illustrated in Figure 2C wherein the internal supporting members SOc is cut at an angle of 90 .

The frame structure produced by the above method can be used to house for example, panelled screen sections 22a, 22b, 22c, 22d, 20a, 20b, 20c, 20d, 24a, 24b, 24c & 24d as in frame structures 30a, 30b, 30c and 30d, or a door 40 as in frame structure 40.

To further ensure the suitability of the fire retardant system 100 for providing a half-hour fire retardancy the door 40 is provided with an automatic door closer (now shown), such as a Perko closer. This is to ensure that, the door 40 automatically is closed after opening so that in the event of fire, the fire retardant system 100 can provide a barrier to withhold the fire.

In the present embodiment, door 40 is formed of a composite material having a PVC-u outer frame 32, into which the Perko automatic closer is housed. To ensure that the fire retardant system 100 does not fail due to fire breaking through a gap where the Perko , or other automatic closer has been inserted into the heat meltable PVC-u material of the door 40 or door frame 32, intumescent material (not shown) is compacted around the portion of the Perko inserted into the door 40 or door frame 32.

It is important that any intumescent material incorporated into the fire retardant system 100 is protected during normal use. Any exposed intumescent material if physically damaged may not expand sufficiently or at all upon the outbreak of fire, : *" thus enabling fire to break-out and causing the system to fail. The present invention I...

*.... 20 therefore provides a door 40 with one or more routed edges into which intumescent -S.

material can be housed. Preferably the routed edged is shaped such that is provides the *S5* dual purpose of protecting the intumescent material and securing the intumescent * : material therein. The door 40 is shown in Figures 1 and Figure 3 having housed within a bottom edge 42 thereof, a strip of intumescent material 60, in this embodiment graphite. In this embodiment, the bottom edge 42 of the door 40 is routed S.....

* into a dovetail profile 44 as can be seen in figure 3A. The intumescent (graphite) material specifically is profiled to fit into the routed dovetail 44, as illustrated in Figure 3B. The intumescent strip 60, by beneficially being housed within the edge 42 of the door, is protected from physical damage during normal operation of the door 40.

To further ensure the half-hour fire retardancy of the fire retardant system 100 when the system 100 preferably incorporates the panelled screens 20a, 20b, 20c, 20d and in a corner arrangement, corner post 18 is provided. The corner post 18 is shown in cross-section in Figure 4A, in which the corner post 18 is shown connected to adjacent frame structures 30b and 30c.

The corner post 18 comprises a substantially square hollow channel section 72, preferably comprising a reinforced channel 102. Extending substantially normally from adjacent sides 75, 77 of the corner post 18 are leg connectors 70d, 70a, 70b and 70c respectively. The leg connectors 70a, 70b, 70c & 70d, are arranged to connectably engage with similarly shaped co-operative connectors 72a, 72b, 72c, 72d. These co-operable connectors affix the corner post 18 to the adjacent frame structures 30b and 30c. In order to form a fire-retardant seal between the frame structures 30b, 30c and the corner post 18, intumescent material, in the form of a strips 60d, 60c is disposed within a cavity of the frame structures 30b, 30c.

Upon the outbreak of fire, the intumescent material 60d, 60c will expand and to ensure that the structural integrity of the corner arrangement holds firm and to prevent the corner post 18 being forced outwardly of the corner arrangement, securing brackets according to one aspect of the invention are provided. The securing brackets * *, 85 may be disposed beneath and/or above the corner post 18. A securing bracket 85 is illustrated in perspective and plan views in Figure 4B and takes the form of a spigot to having a plug portion 89 to be received in the square channel 72 of the corner post 18.

The securing bracket 85 comprises two arm portions 87a, 8Th, adjoined to and ri.! extending from the plug portion 89 and disposed at an angle similar to the angle between the adjacent frame structures 30b, 30c, which in the illustrated embodiment ii S is 90 . The securing bracket comprises fixing apertures 88a, 88b. In the illustrated embodiment, the securing bracket 85 is structured and sized such that the securing apertures 88a, 88b will be aligned with a fixing point (not shown) of the frame structures 301,, 30c. To this end, in one embodiment of the invention a securing bracket 85 is 200mm by 200mm long, the plug portion is 38mm by 38mm square and the arm portions 87a, 8Th are each 40mm wide. This method and assembly has been submitted to Warrington Fire Global Safety for technical approval and has been accredited under report number WF 148957.

Upon reading the foregoing it will be obvious to one skilled in the art that various changes and modifications may be made without departing from the scope of the invention. Indeed, it is envisaged that the intumescent material can be formed of materials other than graphite. In other embodiments, the invention will be applied to a door or door and frame assembly and optionally the corner post and side screen assembly may be or may not be used.

It will be recognised that as used herein, references to intumescent material means any material, with suitable properties for expanding under the temperature conditions associated with the melting of the PVC-u or other plastics material from which the extruded frame structures are formed, thereby to provide a fire seal and structural support.

In other embodiments, the panelled screens 22a, 22b, 22c, 22d, 22e, 20a, 20b, 20c, 20d, 24a, 24b, 24c, & 24d are glazed panels formed from toughened glass or a double glazing. In other embodiments some of the panelled portions 22a, 22b, 22c, 22d, 22e, 20a, 20b, 20c, 20d, 24a, 24b, 24c, & 24d are glazed and some formed from obscure panels of PVC-u.

::::. 20 In other embodiments, the adjacent frame structures 3Gb and 30c, are disposed at * angles other than 90 and in such embodiments the arm portions 87a, 87b will be disposed at a similar angle.

I

S.....

* In an alternative embodiment, the relative angle between the arm portions 87a, 87b : .5.. 25 will be adjustable to enable the securing bracket 85 to be widely applicable. In yet a * :.: further embodiment wherein a post member is affixed next to a structural unit such as a wall, the securing bracket may comprise only one arm, alternatively the securing bracket may comprise more than two arms.

Claims

1. A method of manufacturing a fire resistant frame assembly comprising: providing at least two extruded structural frame members of heat meltable material; providing at least two rigid non-combustible reinforcing members; securing a fixing bracket to an end of one or both of the rigid non-combustible reinforcing members by spot-welding; inserting each of said rigid non-combustible reinforcing members, into one of each of the extruded structural frame members; and fixing said extruded structural frame members together using a mechanical fixing.

2. A method according to claim 2 comprising providing intumescent material internally of the extruded structural frame members.

4. A method according to any of claims I to 3 wherein the rigid non-combustible reinforcing members are each formed from galvanised steel.

5. A fire resistant frame assembly comprising a joined pair of heat meltable :.:::. 20 structural frame members, each heat meltable structural frame member having a rigid *: non-combustible reinforcing member disposed therein, one of said rigid non-combustible reinforcing members being joined by spot-welding to a fixing bracket and one of said heat meltable structural frame members being mechanically fastened * to said fixing bracket. ** * * * S * I

* : *.: 6. A fire resistant frame assembly according to claim 5 comprising a door having along a bottom edge thereof a profiled section for receiving a strip of intumescent material.

7. A fire resistant frame assembly according to claim 6 wherein the profiled section is shaped to receive a strip of intumescent material and securely hold said strip of intumescent material within the profiled section.

8. A fire resistant frame assembly according to claim 7 wherein the profiled section is dovetail shaped.

9. A fire resistant frame assembly according to any of claims 5 to 8 comprising a corner post member affixed to two adjacent heat meltable structural frame members in which intumescent material is disposed between the corner post member and each heat meltable structural frame member, and comprising a bracket for affixing said corner post member and said two structural frame members, the bracket being structured and arranged for maintaining the heat meltable structural frame members affixed to the corner post when the intumescent material expands.

10. A fire resistant frame assembly according to claim 9 wherein the bracket comprises a spigot inserted into a channelled reinforcement of the corner post member and two arm portions extending from said spigot each being fixed to one of the heat meltable structural frame members.

11. A fire resistant frame assembly according to any of claims 6 to 10 comprising an automatic door closer coupled between a hinge edge of the door and an adjacent door frame wherein intumescent material is positioned at least in part around a potion :.:::. 20 of the automatic door closer disposed within the hinge edge of the door and/or door frame. S...

12. A frame for an half-hour fire door comprising extruded PVC-u sections S.....

* and galvanised steel reinforcing sections, the frame comprising a joint, at which joint : * * 25 one of said galvanised steel reinforcing sections is adjoined to a fixing bracket by spot-welding and one of said PVC-u sections is mechanically fastened to said fixing bracket.

13. An half-hour fire door having a profiled section formed in a bottom edge of the door, the profiled section being shaped such that a strip of intumescent material is receivable therein and retainable therein by virtue of the shaped profile.

14. An half-hour fire door according to claim 13 comprising a PVC-u skin.

15. An half-hour fire door according to claim 13 or 14 comprising an automatic door closer coupled between a hinge edge of the door and an adjacent door frame wherein intumescent material is positioned at least in part around a potion of the automatic door closer disposed within the hinge edge of the door andlor door frame.

16. A method of manufacturing a fire resistant frame assembly comprising: providing two extruded structural frame members of heat meltable material; providing intumescent material between one or both of said structural frame members and a corner post member; attaching each extruded structural frame member to a corner post member having a channel section; affixing each of said extruded structural frame members to the corner post member using a securing bracket the securing bracket being structured and arranged for maintaining the heat meltable structural frame members affixed to the corner post when the intumescent material expands.

17. A method of manufacturing a fire resistant frame assembly according to claim 16 wherein the securing bracket is disposed within a channelled section of the corner post member and further portions of the bracket extend along an edge of each of said extruded frame members.

:.:::. 20 18. A bracket for affixing a corner post member to adjacent heat meltable *:::* structural frame members for a fire resistant assembly in which intumescent material is disposed between the corner post member and each heat meltable structural frame * **** member, the bracket being structured and arranged for maintaining the heat meltable * structural frame members affixed to the corner post when the intumescent material .. 25 expands. *

*.**** * 19. A bracket according to claim 18 comprising a spigot receivable in a channelled section of the corner post member and at least two arm portions, the angle between the two arm portions being similar to the angle between adjacent heat meltable structural frame members.

20. A bracket according to claim 19 wherein the angle between the two arm portions is adjustable.

21. A bracket according to either of claims 19 or 20 wherein each arm portion comprises a fixing aperture, the fixing aperture being configured to align with a fixing port of said structural frame member.

22. A method of manufacturing a fire door comprising, routing an edge of the door into a profile for receiving a strip of intumescent material to be received and held therein.

23. A fire-resistant assembly substantially as described herein with reference to and/or as illustrated in the accompanying drawings.

24. A door for a fire-resistant assembly substantially as described herein with reference to and/or as illustrated in Figures 1 and 3 of the accompanying drawings.

25. A structural frame for a fire-resistant assembly substantially as described herein with reference to and/or as illustrated in Figure 2 of the accompanying drawings.

26. A method of manufacturing a fire-resistant assembly substantially as described : 20 herein with reference to and/or as illustrated in the accompanying drawings. * I S... S... * I I'S.

* IIS IS * S :.. 25