GB2277943A

GB2277943A - Blast-proof wall comprising panels and connectors

Info

Publication number: GB2277943A
Application number: GB9309806A
Authority: GB
Inventors: Julian Christopher Melf Notley
Original assignee: NOVOCHECK FIRE SYSTEMS Ltd
Current assignee: NOVOCHECK FIRE SYSTEMS Ltd
Priority date: 1993-05-12
Filing date: 1993-05-12
Publication date: 1994-11-16
Anticipated expiration: 2013-05-12
Also published as: GB2277943B; GB9309806D0

Abstract

An apparatus for constructing walls comprising wall panels 10 and panel connection assemblies 12 wherein, in use, the panels are placed in end-to-end relation and the connection assemblies are secured in spaces between adjacent panels. Each connection assembly engages edge portions 24 of adjacent panels to form a flexible coupling therewith which under a blast incident upon said panels allows said panel edge portions to move relative to the connection assembly and to return toward their initial positions once a blast has subsided. The connection assembly may comprise two U-shaped channel members 20 with side flanges 18, shaped to co-operate with dovetail ends 24 of the panels, which have steel faces 30 sandwiching insulation 28. The members 20 may be of steel; they are bolted together and may have insulation 42, 44 and cover plates 46 associated therewith. <IMAGE>

Description

APPARATUS FOR CONSTRUCTING WALLS The present invention relates to an apparatus for constructing walls and, in particular, an apparatus for constructing walls which are fire resistant and blast resistant.

Walls which are fire and/or blast resistant are often employed to protect equipment and, more importantly, personnel in environments where there is a danger of fires and/or explosions due to the accidental ignition of chemicals. This is particularly true of the oil industry where the accidental ignition of spilled or leaked hydrocarbon compounds is a common occurrence. A difficulty faced in such environments is providing structures which will not only withstand fires but which will also withstand explosive blasts which often precede such fires.

An apparatus for constructing a wall to withstand a blast of the type as aforementioned is known and comprises rigid boards mechanically secured together with steel plates bolted over joints between adjacent boards and with the resulting structure secured to a substantial steel framework. The wall so constructed is designed to withstand blasts. When a blast occurs, the wall will physically arrest the progression of the blast with the shock incident on the wall being transferred onto the steel framework.

A disadvantage encountered with a blast wall constructed from this apparatus is that, since the wall is intended to withstand a blast by physically blocking and deflecting it rather than by absorbing it, the wall including the steel framework must be substantial to provide a desirable level of protection from blasts.

Consequently, the blast walls so constructed are extremely heavy (which is an important consideration in the design of sea-borne oil field installations where it is desired to keep deck weight to a minimum) and, of course, expensive to construct.

European Patent Application No. 90311682.0 describes an apparatus for constructing a fire resistant wall. The wall is of lightweight construction and inexpensive when compared to known alternatives. A wall is constructed from the apparatus, which comprises wall panels and panel connection assemblies, by securing connection assemblies between adjacent wall panels. The connection assemblies each comprise two elongate members, each of which have a "U"-shaped portion and flange portions depending at right angles from side walls of the "U"-shaped portion. In use, the elongate members are secured together within a space between adjacent panels such that the flange portions clamp upon side surfaces of opposing longitudinal edge portions of adjacent panels to thereby secure said panels in end-to-end relationship.The panels comprise an insulating (fire resistant) material sandwiched between surface metal plates which extend throughout the length of the panels and ends of which, in use, abut against adjacent side walls of the "U"-shaped portions of the elongate members comprising the connection assemblies.

When a fire is incident upon the wall thus formed, the surface metal sheets exposed to the fire expand and apply a force to corresponding "U"-shaped portions thereby maintaining the rigidity of the wall enabling it to withstand and to prevent progress of the fire.

A wall constructed from the apparatus described in said European Patent Application is designed to withstand fires only. Under a blast incident upon the panels forming the wall, there is a likelihood that the longitudinal edge portions of the panels would become dislodged from the connection assemblies causing a weakening in the wall structure threatening its structural integrity and therefore its ability to withstand a fire which might succeed the blast.

It is an object of the present invention to provide an apparatus which obviates and mitigates the aforesaid disadvantages.

According to a first aspect of the present invention there is provided an apparatus for constructing walls comprising wall panels and panel connection assemblies wherein, in use, the panels are placed in end-to-end relation and the connection assemblies are secured in spaces between adjacent panels, each connection assembly engages edge portions of adjacent panels to form a flexible coupling therewith which under a blast incident upon said panels allows said panel edge portions to move relative to the connection assembly and which cooperates with said panel edge portions to assist their return to their initial positions once a blast has subsided.

According to a second aspect of the present invention there is provided an apparatus for constructing walls comprising wall panels and panel connection assemblies, wherein the panel connection assemblies each comprise two elongate members, which each have in transverse cross-section a "U"-shaped portion and flange portions depending at acute angles from side walls of the "U"-shaped portion, each flange portion and a corresponding side wall comprise a connecting edge portion, and means are provided for securing the elongate members together in a space between generally opposing longitudinal edge portions of adjacent panels such that the connecting edge portions of said elongate members engage complementaryshaped side portions of the longitudinal edge portions of the panels and the connecting edge portions are capable of flexing from their normal positions to facilitate movement of the longitudinal edge portions relative to the connection assembly under a blast incident upon the panels.

Preferably, the flange portions depend at an angle of less than 60 from the side walls of the "U"-shaped portions.

Preferably, the flange portions depend at an angle of less than 450 from the side walls of the "U"-shaped portions.

Preferably, the complementary-shaped side portions of each panel are located within recessed portions on side surfaces of oppositely facing longitudinal edge portions of the panel.

Preferably, in use, the flange portions of the elongate members are substantially accommodated within corresponding recessed portions of adjacent panels.

Preferably, the panels are fabricated from insulating material sandwiched between surface sheets.

Preferably, the surface sheets are metal plates which may extend throughout the transverse length of the panels.

Preferably, the metal sheets extend throughout the length of the recessed portions of the panels such that, in use, ends of the plates contact with side walls of the "U"-shaped portions of the elongate members.

Preferably, cover plates are provided to substantially enclose the elongate members within the space between adjacent panels such that outwardly facing surfaces of the cover plates lie flush with corresponding surfaces of the panels.

Preferably, the cover plates engage with the elongate members to enclose said members within the space between adjacent panels.

Preferably, the flange portions of the elongate members have end portions with which the cover plates engage to enclose said members within the space between adjacent panels.

Preferably, a filler substance is placed in a gap between the flange portions of the elongate members and end walls of the recessed portions.

Preferably, insulating material is placed in a space between "U"-shaped portions of elongate members located in a space between adjacent panels.

Preferably, insulating material is positioned in a space between an elongate member and a cover plate.

Preferably, insulating material is at least located in the interior space of the 1,U"-shaped portions of the elongate members.

Preferably, the insulating material is fire resistant.

Preferably, the insulating material is compressible.

According to a third aspect of the present invention there is provided a wall constructed from the apparatus according to the next eighteen preceding paragraphs.

The foregoing and further features of the present invention will be more readily understood from the following description of preferred embodiments, by way of example thereof, with reference to the accompanying drawings, of which: Figure 1 shows a perspective view of an arrangement of panels and connection assemblies forming a wall; Figure 2 shows a transverse cross-section through two panels fastened together by a connection assembly, according to the present invention; Figure 3 shows a diagrammatic illustration of the wall of figure 1 illustrating in broken outline the displacement of panels relative to the panel connection assemblies whilst a blast is incident upon said wall.

Figure 4 shows a diagrammatic illustration of the cross-sectional view of figure 2 illustrating the displacement of panels relative to the panel connection assembly whilst a blast is incident upon the panels; and Figure 5 shows a transverse cross-section similar to that of figure 2 for an alternative panel construction.

Referring to the drawings, figure 1 shows a wall constructed from wall panels 10 held together in endto-end relationship by panel connection assemblies 12.

The panels 10 and connection assemblies 12 can be used to construct a fire and blast resistant wall, for example. The apparatus can also be used to construct more complex structures, for example an enclosed room, to protect the enclosed environment (accommodation quarters, for example) initially from an explosive blast caused by the accidental ignition of chemicals, particularly a hydrocarbon blast, and a fire which might result from such an explosion. Conversely, the structure may be used to house apparatus processing potentially explosive substances and thus offer a degree of protection to the external atmosphere.

It is envisaged that the apparatus of the present invention will be most usefully employed in chemical processing installations and on sea-borne installations, particularly oil rigs, where its light weight makes it ideally suitable for air-lifting the apparatus or structures formed from the apparatus onto such installations where, in the past, much more substantial and undesirably heavy structures have been used to provide the desired degree of protection from blasts to both personnel and equipment.

Figure 2 shows a transverse cross-section through a panel connection assembly 12 and the ends 10a, lOb of two adjacent wall panels 10 secured in end-to-end relationship by the assembly 12. The connection assembly comprises a pair of elongate members 14. The elongate members 14 each comprise a U"-shaped portion 16 and flange portions 18 depending at acute angles (approximately 600) from side walls 20 of the "U"- shaped portion 16. Each flange portion 18 and a corresponding side wall 20 comprise a connecting edge portion 22.

When constructing a vertical wall, the elongate members 14 are positioned vertically, and their "U"shaped portions 16 are arranged to enter a gap between generally opposing longitudinal edge portions 24 of adjacent panels 10 such that the connecting edge portions 22 of said elongate members 14 engage complementary-shaped side portions 26 of the longitudinal edge portions 24 of the panels 10.

Corresponding connecting edge portions 22 of the elongate members 14 comprising the connection assembly 12 form a clamping means therebetween to secure a longitudinal edge portion 24 of a panel 10 relative to the connection assembly 12. During the assembly process, the "U"-shaped portions 16 are connected together by means of bolts 25 applied through complementary holes (not shown) in base walls 28 of the "U"-shaped portions 16.

The elongate members 14 are formed of a material such that at least the flange portions 18 are capable of flexing relative to the "U"-shaped portions 16 but preferably the whole of the connecting edge portions 22 are capable of flexing relative to the base walls 28.

The elongate members 14 may be formed from sheet steel profiled to the desired shape. Sheet steel having a thickness of a few millimetres has been found to have characteristics particularly suited to comprise the elongate members 14 which must be sufficiently strong to secure wall panels (typically 1.2 m by 2.4 m) in end-to-end relation, be resistance to fire and yet be sufficiently flexible to allow some movement of the wall panels 10 relative to the connection assemblies 12 when a blast is incident on the panels 10. It will be appreciated that whilst using sheet steel is inexpensive, other suitable material such as thermoplastics or composites might be utilised.

The wall shown in figure 1 constructed from panels 10 and panel connection assemblies 12 and partially shown in more detail in cross-section in figure 2, provides a structure capable of withstanding explosive blasts (typically up to 1.2 bar, 120 KN per m2). The structure achieves this by absorbing the blast rather than trying to physically block and deflect it.

Figure 3 is a diagrammatic illustration of the wall of figure 1 in which the movement of panels 10 relative to connection assemblies 12 under a blast incident upon the panels 10 is shown in broken outline. It can be seen that a blast (depicted in this figure by arrows A) incident on an interior side of the structure causes deflection of the panels 10 relative to the connection assemblies 12.

The structure may in some applications be secured to supporting steel framework (not shown) and this can be considerably less substantial than that required in known constructions of blast walls. The framework acts to support the integrity of the structure and prevent dislodgement of the panels 10 from the connection assemblies 12. However, the supporting steel framework, where included, is such that if allied to known blast wall structures, the resulting structure would not be sufficiently strong to withstand blasts of a magnitude equal to that that can be withstood by a wall constructed from the apparatus of the present invention.

Figure 4 shows a diagram illustrating the displacement of panels relative to a connection assembly 12 whilst a blast is incident upon the panels 10. A blast incident on the panels 10 causes deflection of said panels 10 as previously illustrated in broken outline in figure 3. This results in movement of the longitudinal edge portions 24 of the panels 10 relative to the connection assembly 12. In the range of blast intensities for which the wall is designed to withstand, the blast should not cause dislodgement of the panels 10 from the connection assembly 12 but some relative movement will, of course, occur between them which acts to absorb the energy of the blast.

As illustrated in figure 4, it can be seen that during the period (typically 0.1 secs) a blast is incident on the panels 10 the longitudinal edge portions 24 of the panels 10 will move away from the "U"-shaped portions 16 of respective elongate members 14. Whilst there will be some rotational movement of said longitudinal edge portions 24 relative to the elongate members 14, the significant portion of the movement is a translational movement, signified by arrows B, along a transverse axis through the connection assembly 12.

As a longitudinal edge portion 24 moves away from the "U" -shaped portions 16 of said elongate members 14, the complementary-shaped side portions 26 of said edge portions 24, which between them comprise a wedge-shaped section, act on the flange portions 18 of the elongate members 14 urging them away from the normal positions and causing said portions 18 to flex relative to their corresponding side walls 20 and may even cause the side walls 20 to flex relative to the base wall 28. Angle 81 in figure 4 denotes the angular inclination between a flange portion 18 and a side wall 20, whilst angle ssl denotes the angular inclination between a side wall 20 and a base wall 28.It can be seen from figure 4 that angle 81 > 8, where 8 is the normal angular inclination of the flange portion 18 relative to the side wall 20, and 1 c $ where $ is the normal angular inclination of the side wall 20 relative to the base wall 28.

As the longitudinal edge portions 24 move away from the "U"-shaped portions 16 and urge said flange portions 18 from their normal positions, there are created forces (depicted by arrows F in figure 4) which act between the flange portions 18 at their points of contact with respective complementary-shaped side portions 26. The forces F are a product of the resistance to flexing of the material of the elongate members 14 and the amount by which the flange portions 18 are flexed. Accordingly, as the longitudinal edge portions 24 move farther from the "U" -shaped portions 16, the forces F become progressively larger and progressively act to arrest movement of the edge portions 24 away from the "U"-shaped portions 16. In this way, the connection assemblies 12 act to absorb some of the energy of the blast incident on the wall panels 10.

Other mechanisms may assist in absorbing the energy of the blast. The panels are, in a preferred embodiment, formed from an insulating material 28 sandwiched between outer metal plates 30 which extend the full transverse width of the panels 10. The composite nature of the panels' 10 construction provides the panels 10 with a degree of flexibility.

As has been discussed, when a blast is incident on the panels 10, the panels 10 each deflect (see figure 3) from their normal positions with maximum deflection occurring at their midpoints. In addition to the action of the connection assemblies 12, the deflection of the panels 10 acts to partially absorb the energy of the blast.

Where the wall structure is supported by a main steel framework, the pattern of deflection caused in the panels 10 by a blast incident upon them is altered but deflection of the panels 10 still occurs in a manner which acts to partially absorb the energy of the blast.

In the preferred embodiment, the fire resistant material 28 is compressible thus imbuing the panels with a degree of flexibility as aforesaid. The compressibility of the fire resistant material 28 allows some flexing of the complementary-shaped side portions 26 as the longitudinal edge portions 24 move away from the "U"-shaped portions 16. Thus, as shown in figure 4, al > a, where al is the angular inclination of a complementary-shaped side portion 26 to an end wall portion 32 of a recessed portion 34 in which the complementary-shaped side portion 26 is located and a is the normal angular inclination between said portions. Consequently, the flexing of said complementary-shaped side portion 26 assists in absorbing energy of a blast incident on the panel 10.

When a blast incident on the panels 10 subsides, the panels 10 tend to return to their normal positions although some permanent distortion of said panels 10 may result from the intensity of the blast 10. The action of the panels 10 restoring to their normal positions causes movement of the longitudinal edge portions 24 relative to the connection assemblies 12.

Once again, a portion of this movement will be rotational but is, in the main, translational movement along the transverse axis through the connection assembly 12 towards the "U"-shaped portions 16.

The forces F acting between the complementaryshaped side portions 26 and flange portions 18 act, due to the relative inclination of said portions 18, in a direction generally inwardly and towards the "U"-shaped portions 16. As a result, the forces F act to assist the return of said longitudinal edge portions 24 to their initial positions which they occupied prior to the blast incident on the panels 10.

In use, the flange portions 18 are substantially accommodated within the recessed portions 34, thereby ensuring that the assemblies 12 are flush with corresponding outer surfaces of the wall panels 10.

Furthermore, the surface metal plates 30 extend throughout the length of said recessed portions 34, so that ends 36 of said metal plates 30 abut side walls 20 of the "U"-shaped portion 16 such that, under the influence of heat, the surface metal plates 30 expand and apply force to the "U"-shaped portions 16, thereby maintaining the rigidity of the structure when subjected to a fire after a blast, or otherwise.

Figure 5 shows an alternative embodiment of the invention in which like numerals are used to denote like parts as already described in relation to the first embodiment. In this embodiment, the panels 10 are comprised of a fire resistant material 28 sandwiched between outer metal sheets 30 having recessed portions 34. The outer metal sheets extend over the transverse width of the panels 10. The plates 30 extend throughout the recessed portions 34 but include inwardly depending portions 40 which, in use, abut side walls 20 of "U"-shaped portions 16. When the surface metal plates 30 are exposed to fire, they expand causing the inwardly depending portions 40 to apply a force to the side walls 20 of the "U"-shaped portions 16 thereby maintaining the rigidity of the structure.

Advantages of forming the panels with the metal plates 30 including such inwardly depending portions 40 are two-fold. In the fabrication of the panels 10 the inwardly depending portions 40 act to hold the fire resistant material 28 within the bounds of the metal plates 30 and in use, the inwardly depending portions 40 provide a stronger abutment surface onto the side walls 20 of the "U"-shaped portions 16 than the ends 36 of the plates 30 as described in connection with the first embodiment.

In both embodiments, the bolts 25 securing the elongate members 14 together provide the only thermal path between an interior surface of the panels 10 and an exterior surface. The space between the "U"-shaped portions 16 is filled with an insulating/fire resistant material 42 and the interior spaces of said "U"-shaped portions are also filled with a similar insulating material 44. To complete the connection assemblies 12, cover plates 46 engage with end portions 48 of the elongate members 14 and any gap between the elongate members 14 and the end walls 32 of the recessed portions 34 of the panels 10 are filled with a suitable filler material 50, thereby providing a flush surface along both panels and connection assemblies.

The cover plates 46 are formed of a flexible material and, as can be seen in broken outline in figure 4, when a blast is incident on the panels 10, the cover plates 46 flex outwardly due to the relative moving together of the end portions 48 of the flange portions 18. The cover plates 46 are not essential to the ability of the walls to withstand a fire following a blast incident on the wall and may become removed from the wall by the action of the blast.

Claims

1. An apparatus for constructing walls comprising wall panels and panel connection assemblies wherein, in use, the panels are placed in end-to-end relation and the connection assemblies are secured in spaces between adjacent panels, each connection assembly engages edge portions of adjacent panels to form a flexible coupling therewith which under a blast incident upon said panels allows said panel edge portions to move relative to the connection assembly and which cooperates with said panel edge portions to assist their return toward their initial positions once a blast has subsided.

2. An apparatus as claimed in claim 1, wherein the panel connection assemblies each comprise two elongate members, which each have flange portions depending at acute angles from side walls thereof, each flange portion comprises a connecting edge portion, and means are provided for securing the elongate members together in a space between generally opposing longitudinal edge portions of adjacent panels such that the connecting edge portions of said elongate members engage complementary-shaped side portions of the longitudinal edge portions of the panels and the connecting edge portions are capable of flexing from their normal positions to facilitate movement of the longitudinal edge portions relative to the connection assembly under a blast incident upon the panels.

3. An apparatus as claimed in claim 2, wherein each of the elongate members of the connection assemblies have, in transverse cross-section, a "U"shaped portion from side walls of which the flange portions depend, such that a flange portion and a respective side wall of the "U"-shaped portion comprise a connecting edge portion.

4. An apparatus as claimed in claim 2 or 3, wherein the flange portions depend at an angle of less than 600 from their respective side walls.

5. An apparatus as claimed in claim 2 or 3, wherein the flange portions depend at an angle of less than 450 from their respective side walls.

6. An apparatus as claimed in any preceding claim, wherein the complementary-shaped side portions of each panel are located within recessed portions on side surfaces of oppositely facing longitudinal edge portions of the panel.

7. An apparatus as claimed in claim 6, wherein the flange portions of the elongate members are substantially accommodated within corresponding recessed portions of adjacent panels.

8. An apparatus as claimed in any preceding claim, wherein the panels are fabricated from insulating material sandwiched between surface sheets.

9. An apparatus as claimed in any preceding claim, wherein the panels have surface sheets which are metal plates and which extend throughout the transverse length of the panels.

10. An apparatus as claimed in claim 9, wherein the metal sheets extend throughout the length of the recessed portions of the panels such that, in use, ends of the plates contact with side walls of the elongate members.

11. An apparatus as claimed in any preceding claim, wherein cover plates are provided to substantially enclose the elongate members within the space between adjacent panels such that outwardly facing surfaces of the cover plates lie flush with corresponding surfaces of the panels.

12. An apparatus as claimed in claim 11, wherein the cover plates engage with the elongate members to enclose said members within the space between adjacent panels.

13. An apparatus as claimed in claim 12, wherein the flange portions of the elongate members have end portions with which the cover plates engage to enclose said members within the space between adjacent panels.

14. An apparatus as claimed in any of claims 2 to 13, wherein a filler substance is placed in a gap between the flange portions of the elongate members and end walls of the recessed portions.

15. An apparatus as claimed in any of claims 2 to 14, wherein insulating material is placed in a space between "U"-shaped portions of elongate members located in a space between adjacent panels.

16. A wall constructed from the apparatus according to any preceding claim.

17. An apparatus substantially as hereinbefore described with reference to figures 1 to 4 of the accompanying drawings.

18. An apparatus substantially as hereinbefore described with reference to figure 5 of the accompanying drawings.

19. A wall substantially as hereinbefore described with reference to figures 1 to 4 of the accompanying drawings.

20. A wall substantially as hereinbefore described with reference to figure 5 of the accompanying drawings.