The present invention relates to a resistive material and in particular to a resistive material for providing thermal and blast protection.

The safety of personnel and equipment in the case of an explosion and subsequent fire is especially important for onboard oil and gas facilities both onshore and offshore. This is because, in- hydrocarbon installations, if there is a fire or explosion the intensity of the blast and the high temperatures involved require very special protection. Protection is needed to enable personnel safe passage to fight the fire, control the rig operation or to evacuate the rig and also to obviate damage to equipment and facilities thereby reducing the possibility of secondary explosions.

The oil and gas producing industries have become increasingly aware of the need to provide improved thermal and blast protection in view of disasters, such as the Piper Alpha explosion. Attempts to date to increase protection have included enhancement of existing barriers and the erection of new barriers. However, two requirements on offshore installations have placed extreme constraints on the improvement of thermal and blast protection measures ^' . One requirement is to

2 reduce weight to a minimum which excludes many materials. The other requirement is the manner of installation since if the protection measures require ' hot working' to be carried out during installation, then the rig may need to cease operations until the installation has been completed which, of course, can be extemely costly.

Known protection measures have included:

1. Thermal barriers based upon thin steel plates with either a proprietory cementation or fibrous coating applied after the installation of the steel or with fibrous cementation material sandwiched between steel skins;

2. Blast panels comprising reinforced steel panels to resist pressure from an explosion;

3. Combined thermal and blast barriers comprising reinforced steel panels insulated with layers of fibrous or cementation material. However such layers of insulation can only withstand a very limited structural loading since the cementation is likely to flake off or part of the fibrous material may lift off from the thermal and blast barrier.

4. Composite structures, such as glass reinforced plastic (GRP) provides a structural medium with very low thermal conductivity. Such a material has been used to construct ships including the engine room boundaries. A fire in the engine room of such a ship was contained by the material causing extensive damage to the equipment and aluminium fittings inside whilst causing no damage outside with slight damage to the surface of the material. Similar fires on previous occasions on steel and aluminium ships has resulted in decommissioning of the ship due to the extent of the damage and even sinking of the ship.

Such material has also been applied as cladding of an existing steel deck of an accommodation module of an offshore process rig. As well as providing the necessary thermal protection, the nature of the cladding permits helicopters to land and enables equipment and personnel to be moved on it, advantages not realised by the cementation barriers.

However, cementation materials hitherto have always required attachment to existing structures, since too many problems were encountered when developing self-supporting barriers with sufficient blast _ protection.

An aim, therefore, of the present invention is to provide a resistive material which gives thermal and blast protection and enables the material to be used in self-supporting barriers.

According to the present invention there is provided a resistive material for providing thermal and blast protection against hydrocarbon explosions and fire comprising a composite of:

an insulative material; and a thermally resistive facing circumjacent said insulative material.

Embodiments of the present invention are further defined in the dependent claims 2 to 14.

The present invention also provides a panel comprising said resistive material and a wall comprising a framework for coupling adjacent panels together.

A thermally resistive facing is also provided and comprises a further composite of a resin matrix; reinforcing means; and a thermal membrane.

By way of example only, a preferred embodiment of the present invention will be described with reference to

the accompanying drawings, of which:

Figure 1 is a schematic cross-section of the resistive material according to the preferred embodiment;

Figure 2 is a schematic cut away plan view of the material shown in Figure 1;

Figure 3 is a schematic view of a panel comprising the resistive material and supporting structure; and

Figure 4 is a series of cross-sections illustrating a wall comprising the panels as shown in Figure 3.

As shown in Figures 1 and 2, the resisitive material is a composite material and comprises a central core 2, reinforced by pultrusions 4, and facings 6 either side of said core 2.

By the term pultrusion, one means a continuous production process used for the manufacture of structural sections. Fibrous reinforcement materials are preimpregnated with a thermosetting resin and physically pulled through a heated die to both form the required section shape and initiate a rapid resin cure. The continuous section of finished component is cut into the required length dependant upon the intended end use. Thus, for the purposes of this description a pultrusion is the finished product from such a process.

The central core 2 may be varied to suit the required level of insulation but the preferred embodiment comprises a phenolic expanded cellular foam such as Acell or Cellabond K (both Registered Trade Marks). However, the central core may be selected from one of the group consisting polyurethane, polyvinyl chloride, phenolic, acrylic, polyether sulphone, and polyethene. Alternatively, the central core 2 may comprise a compressed ceramic fibre board or calcium silicate fibre board such as Duraboard or Vermiculux (both Registered Trade Marks ).

The pultrusions 4 add support to the central core and comprise hollow square box sections of glass reinforced plastic (GRP).

The facings 6 of the resistive material comprise a polyester and/or phenolic resin matrix reinforced with woven fabrics 8, such as E-glass woven rovings and in the preferred embodiment, a thermal membrane such as silica 10 for example Dalfratex (Registered Trade Mark). The resin matrix may also be reinforced with non-woven fabrics. The resin matrix may be chosen from the set comprising polyester, vinyl esther, phenolic, epoxy, and urathane. Also the thermal membrane may comprise any one of silica fabric, vermiculite impregnated glass

fabric, ceramic fabrics, ceramic fibrous fillers. Depending upon the thermal rating required, the thermal membrane of the facing may be omitted.

Each of the components of the resistive material are bonded together using a resin based bonding paste, for example Freefix (Registered Trade Mark), and enhanced by the addition of a thermally resistive filler such as Ceepree Fire Barrier (Registered Trade Mark). Other types of bonding pastes include polyester, epoxy, phenolic, polyurathane, and p ^' olyisocyanate.

The resistive material can offer a fire rating equivalent to that of H120.

The resistive material may be formed into a panel 12 such that the pultrusions 4 form a regular structure as shown in Figure 3.

These panels 12 may be attached to the existing steel walls but may also be attached to the upstands on the deck and the deckhead to form self-supporting barriers

Alternatively, the panels 12 may be coupled together to form a wall, 14, sections of which are shown in Figure 4. A structural framework is used to couple adjacent panels 12 and couples the wall 14 to the upstands on the

deck or deckhead. Typically, the edges of adjacent panels 12 are arranged contiguously with a layer of fire resistant material 16 therebetween and along a capping plate 18 on one side and along a supporting frame work such as a vertical ' I' beam 20 on the other side of the panel joint.

The capping plate 18 and the ' I' beam 20 may also be formed from the composite material to form a total wall from the composite material.

The wall 14 may be coupled to the existing stiffened steel deck and walls, and in connection with suitably supported panels 12 to form a roof, completely surround and contain any particular area to provide greatly enhanced thermal and blast protection.

When a total enclosure has been formed, the doors or hatches may also be formed from the composite material.

Since, the panels 12 or wall 14 may be bolted to the existing structures, ' hot working' is greatly reduced thereby minimising the time spent and costs incurred in the installation of such protection. Furthermore, since the protection is in the form of moulded panels which can be produced in a range of shapes, a greater degree of flexibility in application may be offered, thus

enabling the panels to be used in more applications than known hitherto. Being able to mould the panels around • corners is particularly advantageous especially since many known thermally protective materials are not able to be shaped into non-planar formations.

A further embodiment comprises the resistive material without the pultrusions and the advantage of such a material is that it can easily be cut to any desired shape or size. This resistive material should, however, only be used where the required blast rating is low.

Another embodiment comprises the facings 6 being coupled directly to existing stiffened steel structures to provide the requisite thermal protection.

The foregoing description has been given by way of example only and it will be appreciated by a person skilled in the art that modifications may be made without departing from the scope of the present invention. For instance, additional materials may be added to the resistive material to enhance particular properties such as pre-formed glass reinforced phenolic laminates attached to the facings 6 to reduce smoke emission and further reduce the surface spread of flame rating.