Abstract:
The present invention relates to a panel for use in the assembly of a modular hot work habitat so as to form an enclosure to facilitate hot working. The panels comprise a first layer of flexible structural material, and a second layer of flexible fireproof material fixed to the structural layer. A habitat comprising a plurality of interconnected panels is described.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an improved panel, particularly to an improved panel for use in the construction of habitats for surrounding an area in which hot work is to take place. The invention also relates to a habitat constructed from the improved panels. The invention also relates to an improved habitat structure and to a refuge for use in hazardous working environments. 
     2. Description of the Related Art 
     Conducting “hot work” such as welding, cutting or grinding generates heat and sparks. In certain environments hot working can be extremely hazardous, particularly where there may be combustible gases, particularly hydrocarbons, present, for example on oil/gas search and production rigs and facilities, oil refineries, chemical plants and the like. 
     Hot work habitats (or enclosures) permit hot work to be conducted in such environments. A hot work habitat is an enclosure which can be built around the area in which hot work is to be performed. Examples of habitats or enclosures are disclosed variously in U.S. Pat. Nos. 5,018,321, 5,101,604, 452,764. Once built, some habitats can be over pressurised, that is the air pressure within the habitat can be raised above the air pressure external to the habitat to prevent the ingress of potentially flammable gases into the habitat. 
     Conventionally, habitats are made from galvanised sheeting and wooden panelling which can be lined around the floor area with fire resistant matting. However these habitats are inflexible and cumbersome, and flexible, generally one piece, dome structures such as U.S. Pat. Nos. 5,018,321 and 5,101,604 were developed. Since then modular systems comprising flexible flame retardant fabric panels have been developed. Modular habitats have drawbacks however; firstly, in the event of a fire breaking out within the habitat, a modular habitat is not designed to contain the fire; the flame retardant fabric panels only being capable of withstanding temperatures of up to approximately 70° C. Secondly, if the fabric is breached or torn, an equalisation of pressure can result with the possible consequence of an ingress of potentially combustible gases. Such a breach can occur, for example, by performing hot work close to the flame retardant fabric such that a continual shower of sparks from grinding operations or a naked flame burns a hole in the material. The dome structures referred to above are also cumbersome to install and to fireproof adequately. A single breach in the dome renders the whole habitat unusable. Furthermore fire blankets are generally difficult to secure and install in a vertical orientation. 
     Whilst it would be desirable to use fireproof material instead of flame retardant fabric for the panels fireproof material is generally not suitable for stitching i.e. they cannot readily be stitched together to form panel structures or have zips or other fasteners attached thereto to allow panels to be connected together. Whilst it is possible to stitch fireproof materials specialist threads are required to maintain the fireproof integrity of the fireproof panel. It will be appreciated that any connecting means must have at least the same fireproof characteristics as the panels or the integrity thereof would be diminished in the event of a fire. One type of thread that can be used to stitch fireproof panels is a quartz based thread but such threads are generally extremely brittle and thus do not lend themselves to use in the stitching of fireproof panels for use in habitats as the constant handling of the panels would result in the thread breaking. 
     It is an object of at least one embodiment of the present invention to provide an improved panel for a hot working habitat. 
     SUMMARY OF THE INVENTION 
     According to a first aspect of the present invention there is provided a panel for use in the assembly of a modular hot work habitat, the panel comprising:
         a layer of flexible structural material, and   a layer of flexible fireproof material fixed to the layer of structural material.       

     Utilising two layers of flexible material to form a composite panel provides structural integrity, reducing the possibility of the panel, in use, being torn. Additionally, providing a fireproof layer prevents breach of the habitat by sparks or other hot material, and increases the chances of a fire within the habitat being contained. 
     Preferably, the layers are arranged to lie in parallel planes, in a laminated structure. Preferably, the laminated panel is flexible. 
     Preferably, the layer of structural material is a flame retardant material. 
     Preferably, the flame retardant material is a flame retardant fabric. 
     Most preferably, the flame retardant fabric is PVC coated woven polyester fabric coated with plasticized polyvinylchloride in the range of 10-40%; polyethyleneterephtalate in the range of 20-80%; and di-isononylphtalate in the range of 0-30%, thereby providing temperature resistance in the range of −30° C. to +70° C. 
     Preferably, the fireproof material layer is a fireproof fabric. 
     Most preferably, the fireproof fabric is silica chemically treated to create an amorphous silica coating on each side with a high temperature resisting silicone rubber. 
     Preferably the fireproof comprises a base fabric having a weight in the region of 400 g m 2 -700 g m 2 . The weight of the coated fabric is in the range of from 800 g m 2 -1200 g m 2 , typically 1075 g m 2  and has a thickness in the range of from 0.5 mm to 1 mm, typically 0.65 mm. 
     Preferably, the layers are fixed by being adhered to each other by a silicone adhesive. Silicone adhesives are particularly useful as silicone adhesives have a temperature rating that is generally not less than the temperature rating of the fireproof fabric and tend not to burn, therefore assisting in maintaining the integrity of the panel in the event of fire. Other types of flame retardant adhesives may be used such as SPRAYTACK™ adhesive by 3M or flame retardant tapes. 
     Alternatively, or indeed preferably, there may be provided mechanical fixing means to fix two panels to each other in addition to adhering by an adhesive. Typical mechanical fixings may include rivets, nuts, bolts and the like and mechanical fixings are particularly suitable if the panel is used in a vertical orientation. 
     Preferably, the fireproof material contains silicone. 
     Preferably, the panel is arranged such that, in use, the fireproof layer forms part of an internal surface of a habitat. In the event of a fire within the habitat, damage to the habitat is minimised if the fireproof layer forms part of an internal surface of the habitat, if the habitat remains structurally intact the possibility of containing the fire within the habitat is increased. 
     Preferably, the panel includes attaching means to permit the panel, in use, to be attached to an adjacent panel or panels. 
     Preferably, the attaching means are fitted to the structural material layer. 
     Preferably, the structural material layer includes an edge and the attaching means are fitted to the edge of the structural material layer. 
     Preferably, the attaching means extend around the entire perimeter of the structural material layer. 
     Preferably, the attaching means is at least one zip portion adapted to engage with a complementary zip portion fitted to a second panel. Other attaching means which could be used include hooks and eyelets, press studs, turn buttons, lift-a-dot, and nuts and bolts. 
     Preferably, the fireproof material layer has a greater surface area than the structural material layer. 
     Most preferably, a portion of the fireproof material layer extends beyond the edge of the structural material layer. 
     Preferably, the portion extends beyond the edge of the structural material layer around the entire perimeter of the structural material layer. 
     Preferably, the fireproof material layer portion extends sufficiently to protect, in use the attaching means. Providing a portion of fireproof material to cover the attaching means protects the attaching means from a fire, assisting in maintaining the integrity of an assembled habitat. 
     Preferably, in use when the panel is attached to an adjacent panel, adjacent fireproof material layer portions overlap. 
     Preferably, the flame retardant layer of the panel further includes an extended portion formed and arranged to cover the attaching means. 
     Preferably, the at least extended portion in the form of a protection strip which is releasably attachable to the structural material layer. 
     Preferably, the extended portion is releasably attachable to the structural material layer by means of a hook and loop fastener or other mechanical fixings as described above. 
     Preferably, the/each extended portion is flame retardant. 
     Preferably, the/each extended portion is adapted to cover the attaching means. 
     Preferably, the/each extended portion is adapted, in use, to attach to adjacent connected panels. In use, the attaching means, for example a zip, is enclosed on one side by the overlapping first and second fireproof material layer portions and on the other side by the extended portion. Such an arrangement assists in sealing an assembled habitat facilitating over-pressurising of the habitat. 
     Preferably, the fireproof material layer is adapted to withstand temperatures to in excess of 1200° C., typically 1000° C. though materials that are fireproof to higher temperatures e.g. 1600° C., may be employed. 
     According to a second aspect of the present invention there is provided a modular hot work habitat comprising:
         a plurality of connected panels, each panel comprising:
           a layer of flexible structural material, and   a layer of flexible fireproof material fixed to the layer of structural material.   
               

     Preferably, the panels are arranged such that the fireproof material layers face inwards towards the interior of the habitat. 
     According to a third aspect of the present invention there is provided a kit for assembling into a modular hot work habitat, the kit comprising:
         a plurality of panels, each panel comprising:
           a layer of flexible structural material, and   a layer of flexible fireproof material fixed to the layer of structural material.   
               

     In yet another respect the present invention provides a refuge suitable for use in environments where there is the possibility of fire comprising an inner tent like structural assembly, said structural assembly comprising flexible panels formed and arranged for supporting, on its outside, fireproof material fixed thereto. 
     It will be understood some of the features depending from the first aspect of the invention may be equally applicable to the second and subsequent aspects, and are not repeated here for brevity and clarity. 
     Preferably the habitat according to any aspect of the present invention includes an airlock, preferably a fireproof airlock, formed and arranged so as to be securable to said panels. Additionally there may be provided a support structure such as scaffolding for supporting a said habitat according to the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       An embodiment of the present invention will now be described with reference to the accompanying drawings in which: 
         FIG. 1  is a schematic perspective view of a hot work habitat comprising a plurality of connected panels according to an embodiment of the present invention; 
         FIG. 2  is a schematic perspective one of the panels shown on  FIG. 1 ; 
         FIG. 3  is a side view of the panel of  FIG. 2 ; 
         FIG. 4  is an enlarged view of part of  FIG. 3 ; and 
         FIG. 5  is a section view of part of a wall of the habitat of  FIG. 1 , taken along line A-A shown on  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     Referring firstly to  FIG. 1 , there is shown a habitat, generally indicated by reference numeral  10 , comprising a plurality of connected panels  20  according to an embodiment of the present invention. The habitat  10  is designed to be assembled around an area in which hot work is to take place. 
     The connected panels  20  are supported by a structural frame  12  and the habitat  10  also includes an access door  14  for accessing the habitat interior. 
     One of the panels  20  can be seen more clearly in  FIGS. 2 ,  3  and  4 ; perspective, side and enlarged side views of a panel  20 . The panel  20  comprises a flame retardant structural layer ( 22 ) made from Sio-Line FR725 material available from Sioen Coating Distribution n.v. of Belgium, and a fireproof layer made from Fortasil SKSS 600R distributed in the UK by TBA Textiles Ltd. The fireproof layer  24  is secured to the structural layer  22  by a silicone adhesive  26  such as AS1606 by ACC Silicones Ltd. The panel  20  is approximately 2 m by 2 m. 
     In use with the habitat  10 , the fireproof layer  24  faces inwardly towards the habitat interior to assist in containing any fire which may break out within the habitat  10  during hot working. The flame retardant structural layer  22  faces outwards from the habitat  10  to protect the habitat  10  from heat generated externally of the habitat  10 . The composite arrangement of the panel  20  makes the panel  20  better able to withstand activities which might otherwise breach the panel  20 , such as being exposed to a sharp edge or a concentrated shower of sparks. 
     The flame retardant structural layer  22  includes attaching means  28  along its edges  30 . The attaching means  28  in the case of the panel  20  is a series of zip fasteners  28 ; one half of a first zip fastener  28   a  is fitted along a first edge  30   a , one half of a second zip fastener  28   b  is fitted along a second edge  30   b , etc. Each half zip fastener  28   a ,  28   b  is adapted to engage with a complementary half zip fastener (not shown) on an adjacent panel. 
     As can be seen most clearly from  FIG. 2 , the fireproof layer  24  includes a portion  32  which extends beyond the flame retardant structural layer edge  30 . The purpose of this extending portion  32  is to protect the zip fasteners  28 , as will now be explained with reference to  FIG. 5 . 
       FIG. 5  is a section view of part of a wall of the habitat of  FIG. 1 , taken along line A-A shown on  FIG. 1 .  FIG. 5  shows parts of two panels  20   x ,  20   y  which are connected by a zip fastener  28  comprising zip halves  28   x ,  28   y , each half zip  28   x ,  28   y  fitted to a respective structural layer  22   x ,  22   y  of the panels  20   x ,  20   y . The extending portions  32   x ,  32   y  of the fireproof layers  24   x ,  24   y  overlap and cover the zip fastener  28 . As explained above, the fireproof layers  24   x ,  24   y  face inwardly towards the habitat interior. The overlapping extending portions  32   x ,  32   y  cover the zip fastener  28  protecting the zip fastener  28  in the event of a fire breaking out within the habitat  10 . 
     Also visible in  FIG. 5  (and  FIG. 1 ), is a protective strip  34 . The protective strip  34  is made of flame retardant material and protects the external surface of the zip fastener  28  from heat arising externally of the habitat  10 . The protective strip  34  is attached to the panels  20   x ,  20   y  by hook and loop fastenings  36   x ,  36   y.    
     The presence of the overlapping portions  32  and the protective strip  34  also assist in providing a seal around the edges of each panel  20 . The panels themselves are impermeable to hydrocarbon gases. Once assembled the habitat  10  can be over-pressurised, that is the air pressure within the habitat  10  can be raised above the air pressure externally of the habitat  10 . Such an arrangement prevents combustible gases which may be circulating externally of the habitat  10  from entering the habitat and potentially being ignited. 
     Various modifications may be made to the embodiments of the improved panel described above without departing from the scope of the invention. For example, although the panel  20  is described as having a single structural layer and a single fireproof layer, there could be multiple layers of each material. Furthermore, although the described embodiment is arranged with the fireproof layer  24  facing inwards towards the interior of the habitat  10 , in certain circumstances it may be desirable for the fireproof layer  24  to face outwards. 
     It will be appreciated that the principal advantage of the above described embodiments is that a habitat can be assembled which is highly resistant to fire and is structurally stronger than inflatable habitats.