AU2011234233B2

AU2011234233B2 - Fire protected structures and components for fire protection

Info

Publication number: AU2011234233B2
Application number: AU2011234233A
Authority: AU
Inventors: Roger Simpson
Original assignee: Morgan Crucible Co PLC; Morgan Advanced Materials PLC
Current assignee: Morgan Advanced Materials PLC
Priority date: 2010-04-01
Filing date: 2011-03-31
Publication date: 2014-04-03
Anticipated expiration: 2031-03-31
Also published as: WO2011121359A2; GB201005579D0; WO2011121359A3; AU2011234233A1

Abstract

A panel comprises: a framework backing panel formed from a material having a density of less than 4000kg.m

Description

WO 2011/121359 PCT/GB2011/050660 FIRE PROTECTED STRUCTURES AND COMPONENTS FOR FIRE PROTECTION This invention relates to fire protected structures and components for fire protection. 5 The invention is particularly, although not exclusively, related to fire protection systems for marine use. The following description is directed to marine use, although the invention can be used to protect other structures from fire. High speed vehicle ferries built from aluminium alloys require extensive structural 10 fire protection in the vehicle spaces, engine rooms and other critical areas. Generally, this protection is required to maintain fire separation from the walls and other structure for 60 minutes. For large open spaces such as vehicle decks, the preferred method is to use a system of panels incorporating fire insulation and mounted in spaced relationship to the walls or other structural components, leaving an insulating 15 air-gap between the panels and the walls or other structural components to be protected. There are two principal systems in commercial use for fire protection in aluminium alloy ships. 20 The company Colbeck & Gunton's "Rapid Access Composite Passive Fire Protection System" uses a honeycomb aluminium backing panel having a fire-facing layer of expanding felt. This product is secured in place by mounting to a steel sub-structure mounted in spaced relationship to the structure of the ship. The expanding felt is thin, 25 but on exposure to fire expands to many times its original thickness to provide an insulating layer. Steel cover strips lie over the joins between panels to prevent fire access to the back of the panel. This product is relatively light but is vulnerable to water absorption and easily 30 damaged, so requiring regular panel replacement. Additionally the high cost of the honeycomb aluminium backing component makes this product expensive. 1 WO 2011/121359 PCT/GB2011/050660 The company Austal Ships use a stainless steel panel system comprising blanket insulation housed in steel cladding. This panel is heavy due to its large steel content. The panels are made of steel with FireMasterTM blanket insulation inside, which is retained by pins welded to the inside of the panel face. These panels are mounted onto 5 an insulated subframe which is attached to the bulkhead or deck structure using metal supports welded to the aluminium structure. The panels are attached to the sub-frame using self tapping screws and the joints between the panels are protected with a steel cover strip 10 In a fire, temperatures can reach 1000 C or more and so any metal exposed to the fire, and supporting structures, are conventionally made of steel. The melting point of steel is above 1400 0 C. The applicant has realised that using a lighter material than steel provides significant is weight advantages. The applicant has further realised that using a framework backing panel rather than an aluminium honeycomb backing panel provides significant cost advantages over the Colbeck & Gunton "Rapid Access Composite Passive Fire Protection System", and 20 further can avoid water absorption leading to discolouration of the panels. By providing a framework of lighter material than steel, and protecting the framework at least in part from exposure to the temperatures reached in a fire, a fire protection system can be achieved that is lighter than the Austal Ships system, and more cost 25 effective and less prone to damage than the Colbeck & Gunton "Rapid Access Composite Passive Fire Protection System". Part of the philosophy of the invention it to dispose the insulation so as to protect structural components that would suffer through exposure to a temperature of 1 000 0 C 30 or more. Such components could be, for example, formed of low density metals such as aluminium, aluminium alloys, magnesium, or magnesium alloys. Both aluminium and magnesium have melting points below 700 0 C. Other materials may be used for structural components if suitably protected; for example, fibre reinforced plastic 2 3 components. Fibre reinforced plastics may be obtained that have a maximum temperature of use of 200*C or more. However part of the invention also lies in the realisation that while rigidity of the panels are necessary in everyday use, it is not necessary to have high rigidity after a fire, and so the material facing the fire can be "sacrificial": providing a degree of rigidity while present, but disposable in the event of fire. Further, the applicant has realised that by providing additional fire protection in the sub structure to which the panels are mounted, additional protection can be achieved. Object of the Invention It is an object of the invention to substantially improve upon the prior art at least to an extent or to provide an alternative thereto. Summary of the Invention Accordingly, in a first aspect, there is disclosed herein a panel for marine use comprising * a framework backing panel formed from a material having a density of less than 4000kg.m- 3 ; e a facing on the exposed side; and, e an insulation material housed within the framework backing panel and disposed to protect the framework backing panel, at least in part, from a fire on the exposed side of the panel and in which part at least of the framework backing panel and/or the facing is formed from a material that cannot maintain structural integrity when exposed to 1000*C or more. With a preferred feature that the facing is formed from a material having a density of less than 4000kg.m- 3 . This should be interpreted as indicating that a significant part of the framework backing panel and/or facing is formed from the material that cannot maintain structural integrity when exposed to 1 000*C or more, such that failure of the framework and/or facing could be expected upon exposure to 1000*C. The whole of the framework and/or facing could be formed of such materials.

4 By framework backing panel is meant a framework providing a backing and support for the insulation. The framework backing panel may comprise edge members and stiffening members, which may extend from at least one edge member to at least one other edge member. The framework backing panel in effect provides an apertured panel. The area of the apertures at the back of the panel may be larger than the area of the edges and stiffening members of the framework and may be more than twice the area of the edges and stiffening members of the framework. In a second aspect, there is disclosed herein a marine structure comprising e at least one structural component requiring protection from fire e at least one fire protective panel as in the first aspect of the invention e a sub-structure secured to or in spaced relationship to the at least one structural component and wherein the at least one fire protective panel is mounted to the sub-structure to lie in spaced relationship from said at least one structural component. Further features will be apparent from the appended claims and in the light of the following illustrative description and drawings in which: Fig. 1 shows a panel in accordance with the present invention; Fig. 2 shows another view of the panel of Fig. 1; Fig. 3 shows details of a panel in course of manufacture; Fig. 4 shows details of a panel in course of manufacture; Fig. 5 shows a conventional sub-frame; Fig. 6 shows detail of mounting panels to the sub-frame of Fig. 5; Fig. 7 shows schematically an alternative form of sub frame in accordance with the present invention; and WO 2011/121359 PCT/GB2011/050660 Fig. 8 shows schematically a form of panel construction in accordance with the invention. None of the Figures should be taken as limiting the invention in any way, and should be taken as illustrative only. 5 The invention is illustrated by reference to a fire protection system for high speed aluminium ships and boats. The system comprises panels and sub-frames for mounting the panels. The present invention is not limited to the specific construction shown and many design variants will be evident to the person skilled in the art. 10 The panels Figs. 1 and 2 show a panel in accordance with the present invention. Fig. 1 shows the wall-facing side of a panel 1 comprising: a framework backing panel 15 comprising light aluminium framework edges 2 and stiffening members [not shown]; and an aluminium foil backing 4. The panel has, on the reverse exposed or fire-facing side, an aluminium sheet metal face 5 ("sacrificial" in a fire). Sandwiched between the aluminium foil backing 4 and the aluminium sheet metal face 5 is a layer of insulation blanket. 20 Framework The framework backing panel comprises angle aluminium framework edges 2 and aluminium strip stiffening members 3 forming a lattice- or grid-like panel. A typical panel size would be, for example, 1.2m x 2.4m. For such a size panel to have a low 25 areal density (e.g of about 8kg.m- 2 or less, for example 6.5kg.m- 2 ) the front facing aluminium panel is typically 1mm thick or less, typically 0.8mm with a frame made of aluminium sections with a wall thickness of 1-2 mm, typically 1.5mm or less. However thicker sections may be used if weight is not so critical and the areal density of the panel also varies with the areal density of the insulation. Typically, a 75mm 30 width strip is formed into a U-section with a base of ~30mm width, a longer arm of the U being of about 35mm width and a shorter arm being of about 10mm width. The shorter arm is secured to the sheet metal face, and edge of the insulation blanket is secured under the longer arm. By having edge members and stiffening members extending from at least one edge member to at least one other edge member a degree 5 WO 2011/121359 PCT/GB2011/050660 of rigidity is provided to the framework panel that would not be present if simply the edges were used. Further the stiffening members can act as supports for the insulation as discussed below. The present invention is not restricted to the framework design and materials mentioned and alternatives falling within the scope of the claims and 5 providing both backing and a housing for the insulation will be apparent to the person skilled in the art. Sheet metalface This material is present mainly to provide protection to the refractory insulation, but 10 may also provide some rigidity. The present invention does not exclude metal foil being used for this integer. However, while foil would provide some protection to the refractory insulation it is preferred to have a more robust material and so a material of greater thickness is preferred. Typically the sheet metal face is greater than 0.2mm thick, optionally greater than 0.5mm thick, and normally less than 2mm thick, for is example less than 1mm thick. A suitable material for the sheet metal face 5 is 6WL pattern, gauge 20 [~0.8mm thickness] dimpled aluminium. The dimpling provides added rigidity to the sheet, and additionally the dimpled surface is easy to clean and decorative. The sheet metal face may therefore provide a degree of rigidity to the panel and provides protection against mechanical and water damage. Optionally the 20 sheet metal face may be formed from a material that does not have a density less than 4000kg.m-3. Although exemplified with reference to a sheet metal face the present invention is not limited thereto. The face of the panel may be of a sheet material that includes materials other than metal, and may be entirely non-metallic. 25 Insulation The insulation can be any suitable material that provides adequate insulation to protect the framework at least in part during a fire. Blanket insulation is particularly useful. A suitable material is FireMaster@ Marine Plus Blanket available from Thermal Ceramics (www.thermalceramics.com). Typically a blanket density of 30 70kg.m- 3 and thickness 20-25mm will suffice, but the thickness of required insulation will depend upon the distance between the structure to be insulated and the panel. To some extent, the smaller the distance, the thicker the insulation needs to be. The present invention is not limited to any particular material or thickness of insulation. 6 WO 2011/121359 PCT/GB2011/050660 Desirably the system meets the requirements of the International Maritime Organisation [IMO] Fire Test Procedure Code for aluminium divisions. When heated to the temperature/time curve defined in IMO resolution A754(18), the unexposed face of a protected bulkhead or deck division must be sufficiently insulated so that its 5 average temperature does not rise more than 140 'C above the temperature at the start of the fire test with no point rising more than 180 'C above the temperature at the start of the test. In addition, for aluminium bulkheads and decks, the temperature of the structural core of the aluminium bulkheads and decks must not exceed 200 0 C above the temperature at the start of the fire test. While it is not essential to the 10 present invention to meet this test, it is desirable. The present invention is not limited to use of blankets, and other forms of insulation may be used [e.g. boards, papers, textiles] with appropriate design of the framework backing panel. 1s Panel manufacture Figs. 3-4 show the course of assembly of a panel. Fig. 3 shows the framework backing panel (with framework edges 2, with stiffening members 3 forming part of the framework backing panel) in more detail during the 20 course of assembly of a panel. The framework edges 2 and stiffening members 3 can be made, for example, by pop-riveting together the angle section strip forming the panel edge and the strip forming the stiffening members. Other methods, for example welding, may be used to assemble the framework. 25 Anchors 6, for retention of the insulation blanket, are secured to the framework edges 2 and stiffening members 3. The anchors may comprise threaded rivets [e.g. those sold under the RIVNUT@ trade mark] or may be secured in other ways, e.g. welding. The aluminium sheet metal face 5 is secured to the framework edges 2, and optionally 30 to the stiffening members 3, by riveting or by any other suitable means. Fig. 4 shows the panel 1 after the aluminium sheet metal face 5 has been secured to the framework edges 2 and stiffening members 3, and after insulation blanket 7 has been placed into the shallow tray comprised by the framework edges 2 and aluminium 7 WO 2011/121359 PCT/GB2011/050660 sheet metal face 5. Washers 8 secured to the anchors 6 hold the insulation blanket in place. Finally, the aluminium foil backing is secured to the panel. Additional bracing and 5 securing strips 9 [see Fig 1] may be used to hold the foil in place. Such strips would typically be of aluminium having a thickness of 1-2mm, e.g. 1.5mm and are typically of U-section with base and arms of the U being of about 10-12mm in width. The present invention is not limited to strips of these dimensions and is not limited to the layout and method of assembly indicated. 10 The sub-frame The panels described above may be mounted to a conventional steel sub-assembly, but that does not achieve the full weight saving achievable by the invention. 15 Fig.5 shows a conventional sub-frame 10 as used in Colbeck & Gunton's "Rapid Access Composite Passive Fire Protection System". The sub-frame comprises steel frame sections 11 secured to corner sections 12 bearing securing discs 13. The sub frame is mounted in spaced relationship to the structure 14 to be protected from fire, leaving a gap 15 between the structure 14 and sub-frame 10. 20 The securing discs 13 are rotatable and comprise gaps 16 that can be aligned so as to permit a panel to be installed within the sub-frame, and then rotated so as to secure the panel in place in the sub-frame [in position as shown in Fig. 5]. 25 After the panels are in place, steel cover strips 17 and cover caps 18 are positioned to lie over the panel edges. These are secured respectively by bolts 19 to threaded holes in the steel frame sections 11 and securing discs 13 as shown in Fig. 6. Both the cover strips and corner caps have expanding felt insulation designed and positioned to "seal" against the panel during a fire. 30 The panels of the present invention can be mounted to such a sub-frame. However, disadvantages to such sub-frames are: being of steel, they are heavy 8 WO 2011/121359 PCT/GB2011/050660 the panels do not cover the entirety of the sub frame and rely on the steel cover strips and expanding felt insulation to prevent access of fire to the rear of the panels. 5 Accordingly, the applicant has realised that by use of a light (e.g. aluminium) sub frame, weight can be reduced; and further, that by appropriate design the front cover strips can be dispensed with. The densities of some common metals are given below: Material Approximate Density Approximate Melting (kg.m- 3 ) point 0 C Steel 7480-8000 1510 Aluminium alloy 2550-2800 660 Magnesium alloy 1750-1880 650 10 Fig. 7 shows an alternative form of mounting for fire protection panels. Panels, 20, 21 as described above are mounted to a sub-frame 22 in accordance with this aspect of the invention. The sub-frame 22 can be mounted in spaced relationship to a structure to be protected from fire, leaving a gap between the structure and sub-frame 22. is Spacers 25 may be secured to the structure to be protected from fire and the sub-frame 22. The sub-frame 22 comprises channel section light metal frame sections 23 [e.g. of aluminium with a thickness in the range 1-2mm, typically 1.2mm and formed from 20 strip of about 100mm width], within which is housed insulation material 24. As shown, the channel section is deep and insulation of similar thickness and nature to the blanket of panels 20 and 21 is shown, however the channel could be shallow and a material such as an expanding felt used instead. 25 Assembly The panels 21 and 20 are mounted to the sub-frame 22 by bolts 26 and nuts 27. The bolts 26 pass through plastic grommets 28. Holes 29 in the exposed face of the panels 20,21 provide access to the bolts 26; the insulation in the panels 20, 21 can be moved 9 WO 2011/121359 PCT/GB2011/050660 aside during mounting and moved back once installed, or channels may be provided in the insulation that is filled by insulation after installation, e.g. loose insulation or an insulating mastic. 5 The plastic grommets will cater for differential expansion between panels 20,21 and sub-frame 22 in the event of fire. A similar effect of protecting against differential expansion or movement between parts of the panel and/or sub frame can be achieved by providing over-sized holes and/or holes in the form of slots to permit relative movement of the components. 10 A protective cover strip 30 hides the join between adjacent panels, and covers any necessary access holes 29. This could be an insulated cover strip as is conventional (for example, a steel cover strip), or it could be an uninsulated fire resistant strip, or it could be of a material that is not fire resistant, but merely protects the join against 15 everyday damage. It should be noted that in this construction the aluminium framework of the panels 20 and 21 is not protected by insulation where it underlies the decorative cover strip 30. However, protection is maintained since: 20 * the blanket within the panels 20 and 21 may be under lateral compression and so may expand into any gap caused by melting of the framework edges; and * the edges of the panel are supported by insulation 24 which can act to seal against the back of the framework. 25 This arrangement enables the gap between adjacent panels to be minimised, so reducing the risk of fire penetrating to the back of the panel. Additional protection may be obtained by providing expanding insulation at the edges of the panels. Fig. 8 shows two panels 20, 21 which have recesses 31, 32 on the 30 abutting edges of the panels. These recesses are adapted to house strips of expanding felt that, in normal use, lie within the recesses but which, on exposure to fire, expand to seal the gaps between adjacent panels. The expanding insulation may be secured to 10 WO 2011/121359 PCT/GB2011/050660 the panel edges otherwise than in recesses, but housing them in recesses reduces the risk of damage in handling. Test results 5 In tests of panels as shown in Figs. 1-4 mounted at 550 mm from a "steel structure" on aluminium sub-frames and using steel cover strips as shown in Figs. 5-6, the sub frame and the panels met the A60 requirement of IMO Fire Test Procedure A 754(18). After the test, the aluminium sheet metal face 5 had melted away, but the supporting 10 framework, anchors, and sub-frames had sufficient strength to retain the blanket in place, and so maintain fire protection for the 60 minutes required by the test. The aluminium surface is designed to be sacrificial in a fire while the refractory [e.g. FireMaster®] insulation, being supported by the panel framework, remains in place to is provide the necessary insulation in the fire test. The aluminium framework is protected by the cover strips fitted over the panel joints and by the blanket insulation inside the framework. Alternative arrangements are also possible for cover strips and panel retention as the main anchoring mechanism for the blanket and the fixing points for the panel are insulated by the blanket. 20 The lightest panel that met the A60 requirement of IMO Fire Test Procedure A 754(18) used 70kg.m 3 25mm thick Firemaster@ Marine Plus Blanket. This gives a 1.75 kg.m- 2 blanket areal density and panel areal density 7.65 kg.m 2 25 However, it should be noted that fire resistance depends upon the environment and the amount of insulation required to achieve a desired level of fire protection may vary. For example, as aluminium has a higher thermal conductivity than steel a greater thickness of insulation may be needed to provide A60 level protection to an aluminium structure. 30 As will be apparent from the above, the example given is illustrative and many variants within the claimed invention will be evident to the person skilled in the art. 11

Claims

1. A panel for marine use comprising: * a framework backing panel formed from a material having a density of less than 4000kg.m~ 3 ; e a facing on the exposed side; and, e an insulation material housed within the framework backing panel and disposed to protect the framework backing panel, at least in part, from a fire on the exposed side of the panel and in which part at least of the framework backing panel and/or the facing is formed from a material that cannot maintain structural integrity when exposed to 1 000*C or more.

2. A panel, as claimed in Claim 1, in which the facing is formed from a material having a density of less than 4000kg.m 3 .

3. A panel, as claimed in Claim 1 or Claim 2, in which the framework backing panel and/or the facing is formed from a material having a density of less than 3000kg.m- 3 .

4. A panel, as claimed in Claim 3, in which the framework backing panel and/or the facing is formed from an aluminium or magnesium alloy.

5. A panel, as claimed in any of Claims 1 to 4, in which the framework backing panel comprises joined sections of material having a thickness greater than 0.5mm.

6. A panel, as claimed in Claim 5, in which the joined sections of material have a thickness in the range 1-2mm.

7. A panel, as claimed in any of Claims 1 to 6, in which the facing has a thickness greater than 0.2mm.

8. A panel, as claimed in claim 7, in which the facing has a thickness greater than 0.5mm.

9. A panel, as claimed in claim 8, in which the facing has a thickness less than 2mm.

10. A panel, as claimed in claim 9, in which the facing has a thickness less than 1mm. 13

11. A panel as claimed in any of Claims 1 to 10, in which the insulation material is housed under compression, such that in use melting of part of the framework backing panel will permit the insulation material to expand into the space vacated by the melted part of the framework backing panel.

12. A panel as claimed in any of Claims I to 11, in which the insulation material is an insulation blanket.

13. A panel as claimed in any of Claims 1 to 12, in which expanding insulation is provided at one or more of the panel edges.

14. A panel as claimed in Claim 13, in which the expanding insulation is housed in one or more recesses in said one or more of the panel edges.

15. A marine structure comprising : e at least one structural component requiring protection from fire e at least one fire protective panel as claimed in any one of Claims 1 to 14 e a sub-structure secured to or in spaced relationship to the at least one structural component and wherein the at least one fire protective panel is mounted to the substructure to lie in spaced relationship from said at least one structural component.

16. A marine structure as claimed in Claim 15, in which the sub structure has channels housing insulation material disposed such that the edges of the at least one fire protective panel overlies said insulation material.

17. A marine structure as claimed in Claim 15 or Claim 16, in which said sub-structure is formed at least in part from a material having a density of less than 4000kg.m" .

18. A marine structure as claimed in any one of Claims 15 to 17, in which said sub-structure is formed at least in part from a material that cannot maintain structural integrity when exposed to 1000*C or more.

19. A marine structure as claimed in any one of Claims 14 to 18 which is a marine vessel. 14

20. A marine structure as claimed in any one of Claims 14 to 19 in which the spacing between said at least one structural component and the panels is in the range 50mm to 600mm. The Morgan Crucible Company plc Patent Attorneys for the Applicant/Nominated Person SPRUSON & FERGUSON