The provision of such services or utilities known from the prior art is shown illustratively in Figure 1 of the accompanying drawings. The floor zone consists of four layers 10,11,12,13. One of the layers is the structural layer 11, typically constructed from concrete beams 22. This layer is the load-bearing section of the floor zone and provides the support for all of the other layers. Resting on top of this layer is the suspended computer floor 10.

This layer comprises the floor surface 16, mounted on supports 17 resulting in a void 18.

Cables 20,21 to provide electricity, telecommunications and IT are routed through the void.

Terminal boxes 15 are set in the floor surface 16 with connections 19 to the cabling in the void. Equipment can then be connected with standard connectors to the terminal boxes for the provision of power, telecommunications and IT.

The third layer 12 of the known floor zone is a void 23 which contains further building services. Typically there may be water pipes 24, air conditioning ducts 25, further power cabling and lighting cabling 27 and gas pipes 28. Several of these pipes and cables may, for convenience be located in a tray 29 suspended from the structural layer 11. Others may be directly suspended from the structural layer.

The final layer is a suspended ceiling layer 13. Typically the ceiling 32 is suspended from the structural layer 11 and has lighting units 31 and air supply/extract vents mounted within it.

According to a first aspect of the present invention there is provided : a prefabricated flooring system comprising: at least one structural beam with at least one elongate cavity within it ; at least one conduit for providing a building service; wherein said conduit is attached to the inside of said cavity.

In a preferred embodiment of this aspect of the invention at least one of the structural beams is formed from a composite material.

In a further preferred embodiment of this aspect of the present invention at least one of the structural beams comprises an elongate, substantially closed, outer shell.

In preferred embodiments of this aspect of the present invention the conduits for providing a building service may be one or more of an air conditioning duct, an electric cable, an electric bus-bar, a telecommunications cable, a cable for linking information technology equipment, an optical fibre, a water pipe, a gas pipe, electric lighting cable, fancoil unit intermediate transfer fluid in-pipes, fancoil unit intermediate transfer fluid out-pipes and a cable for an emergency alarm system.

In a yet further preferred embodiment of this aspect of the present invention at least one of the structural beams further comprises at least one opening between the external surface of the structural beam and at least one cavity containing at least one conduit for providing a building service.

According to a further aspect of the invention there is provided a method of building a structure, said method comprising : providing and installing at least two supporting members; providing at least one structural beam of a prefabricated flooring system and arranging it to be supported by said supporting members; said structural beam having at least one elongate cavity within it; and providing at least one conduit for a building service within said elongate cavity in said structural beam.

In preferred embodiments of this aspect of the present invention at least one of the supporting members may contain an elongate cavity with a conduit for providing a building service within it and the method of building a structure may include a step of connecting at least one conduit in the prefabricated flooring system with the conduit in the supporting member.

In further preferred embodiments of this aspect of the present invention at least one conduit for providing a building service is provided in at least one of the prefabricated flooring system and the cavity in the supporting member prior to the prefabricated flooring system and the supporting member being installed.

The present invention is advantageous because it can reduce the total depth of the floor zone. The floor zone in the known art has a typical depth of 1000-1200 millimetres or

more whereas the floor zone of the present invention can be about 500 millimetres in depth.

This is extremely advantageous in the construction of office buildings where the total height of the building is often limited by planning regulations. In such cases reducing the depth of the floor increases the number of levels that can be included in the building and therefore can make the building more profitable.

The present invention is also advantageous because many of the building services can be integrated into the structural beam off-site allowing semi-complete modules to be brought to the site and assembled directly to the structure. This reduces the on-site construction activities, reducing the time taken to construct the building. In addition the prefabrication of components off-site results in improvements in construction quality.

A further advantage of the present invention is that the structural capacity of the flooring system of the present invention is greater than can be achieved in the flooring system of the prior art. Consequently the number of vertical supporting elements (columns) which are required is reduced, providing a clearer and more flexible internal space.

The invention will further be described with reference to the accompanying schematic drawings in which : Figure 1 is a cross-section of a floor zone of the previously known design; Figures 2a, 2b, and 2c are cross-sections of examples of the reinforced box beams used in the present invention; Figure 3 is a cross-section of the beam of Figure 2a with services installed according to a preferred embodiment of the invention; Figure 4 is a cross-section of the beam of Figure 2b with services installed according to a further embodiment of the invention ; Figure 5 is a cross-section of a part of a floor comprising the floor beam of Figure 3 illustratively showing the floor providing the required services to the rooms above and below; Figure 6 is a cross-section of a part of a floor comprising a variant of the floor beam of Figure 3 illustratively showing the floor providing the required services to the rooms above and below ; Figure 7 is a cross-section of a variant of the floor beam of Figure 3 provided with a fancoil air conditioning system; Figure 8 is a simplified floor plan of an office building constructed according to the method of the present invention;

Figure 9 is the sectional view marked AA in Figure 8; Figure 10 is the sectional view marked BB in Figure 8; Figure 11 is the sectional view marked CC in Figure 8.

As described above there are a variety of building services which need to be provided in a building or similar structure and often these need to be incorporated in the floor zone so that they can be accessed at multiple locations on the floor plan. Examples of the types of services that should be provided include telecommunications and IT cabling, power and lighting cabling, air ducts, gas and hot and cold water pipes, cabling for emergency alarm systems and cabling for P. A. systems. In addition to providing access to the building services the floor zone must also provide routing for these services. In the case of telecommunications, IT and power cabling, sockets are required which fit standard plugs. For air conditioning there must be provided air extract and supply vents; and for the lighting system the floor zone should provide mounting points for standard lighting units.

In buildings with specialised functions there are a variety of other building services which can be incorporated into the floor zone. Hospitals, for example, have pipes for the provision of gases such as compressed oxygen and in factories there are pipes for the provision of compressed air to drive pneumatic devices, pipes to connect vacuum pumps, and pipes to provide cutting fluids.

The primary function of the floor zone is to provide a structurally rigid surface. In the present invention this is provided by beams which are comprised of an outer shell with reinforcing members within the shell. Although the invention is not intended to be limited to the use of a particular cross-section of beam, Figures 2a, 2b, and 2c show some suitable examples of beam cross-section.

In a preferred embodiment the cross-section of the beam 50 is a regular trapezium (a quadrilateral in which two of the sides are parallel and the remaining two are of equal length) with two reinforcing members within,. as shown in Figure 2a. The two parallel faces of the trapezium-shaped cross-section form the flanges 52,55 of the beam. Webs 54,57 (which are the two equal sides of the trapezium-shaped cross-section) form the remainder of the outer shell of the beam cross-section and may be more slender than the flanges. The reinforcing members are two webs 53,56 which, in a preferred arrangement are parallel to the external edge webs 54,57 (53 is parallel to 54 and 56 is parallel to 57) and are located in the trapezium-

shaped cross-section such that it is divided into three frustro-triangular cavities 51 which are approximately equal in size.

In an alternative arrangement, shown in Figure 2b, the beam 60 has parallelogram- shaped cross-section. The two longer sides of the parallelogram form the flanges 62,65 and the shorter sides form the external edge webs 64,67. Reinforcing the beam there are three webs 63,66,68. The middle reinforcing web 63 is parallel to the external edge webs 64,67 and the outside two webs 66,68 are parallel to one another and at an angle to the flanges which is the same as the angle of the middle web 63 but in the opposite sense. The reinforcing webs are positioned such that the cross-section is divided into four frustro- triangular cavities 61 which are substantially equal in size.

Figure 2c shows a third beam that would be suitable for use in the present invention.

In this case the cross-section of the beam 70 is substantially rectangular, the longer sides formed from flanges 72,75 and the shorter sides from webs 74,77. Within the rectangular cross-section there are two arcuate reinforcing members 73,76 each of which is joined to either end of one of the two long sides of the beam cross-section and tangentially coincide with the other of the two long sides at the mid point. The two arcuate members are therefore curved in opposite senses and intersect each other. This results in a variety of cavities 71 within the beam.

The cavities in each of the reinforced beams described above extend throughout a substantial part of the length of the beams and are used to route the building services in the finished structure.

The beams are preferably formed from an advanced composite material comprising a high modulus, high strength and high aspect ratio reinforcing material encapsulated by and acting in concert with a polymeric matrix. In preferred embodiments the reinforcing material comprises long fibres of one or more of : E glass, R glass, carbon or aramid. The polymeric matrix comprises one or more of epoxy, vinyl ester, phenolic or isophthalic resins. The fibres occupy from 60% to 80%, preferably 70%, of the material by volume.

The beams are preferably manufactured by a pultrusion or prepreg process and may be manufactured in continuous lengths which are subsequently cut to size.

Figure 3 shows the floor beam 100 used in a preferred embodiment of the present invention. In this case a beam with a trapezium-shaped cross-section (as described with reference to Figure 2a) is used. The shorter of the two parallel'faces is the top flange 152 of the floor beam and the longer is the soffit 155 (lower face of the floor beam). The floor beam

100 has three cavities 111,112,113. The first cavity 111 in this example is used to carry an air conditioning duct 125. At evenly spaced intervals along the floor beam there are a first series of holes through the flange, connecting the first cavity 111 to the exterior of the floor beam.

Air conditioning vents on the exterior of the floor beam are connected to the air conditioning ducts via these holes (which are normally covered by vent louvres).

The second cavity 112 is used to carry a variety of building services such as power cabling 131, telecommunications and IT cabling 134, gas and water pipes 132. As a preferred option a tray 130 may be suspended in the cavity 112 to support the variety of cables and pipes. At evenly spaced intervals along the floor beam there are a second series of holes 153 connecting the second cavity 112 to the exterior of the floor beam. The spacing of the second series may or may not be related to the spacing of the first series of holes. Terminal boxes are mounted inside the holes 153 to provide connections to the services in the second cavity 112.

In the example shown in Figure 3 the terminal box 115 is used to provide connections to the power cabling 131 and the telecommunications and IT cabling 134. Connecting cabling 133 is provided to connect the terminal boxes to the cabling 131,134 within the cavity. The connecting cabling 133 is long enough to allow the terminal box 115 to be removed from the hole 153 in the floor beam 100 to provide access to the cavity for connecting and disconnecting the connecting cabling 133 to (and from) the cabling 131,134 within the cavity.

The terminal box 115 is provided with standard sockets which can receive standard power plugs 116 and standard telecommunications and IT plugs 118. Simple variants of the terminal boxes are used to provide similar, standard connections to the gas and water pipes or any other building services within the cavity.

In a notable variation (not shown) of this embodiment the power cabling in the cavity is replaced by electric bus-bars. The electric terminal boxes in this variation are modified such that the connections to the electric sockets in the terminal boxes automatically connect to the bus-bars when the terminal boxes are mounted in the openings, thus substantially reducing the fitting time, and providing flexibility for easily moving the terminal boxes even after the building has been completed.

The third cavity in this example is used for the lighting. A third series of holes 154 are provided in the soffit 155. Lighting units 130 are then mounted within the holes and connected to lighting cabling (not shown) within the cavity 113. As with the terminal boxes 115 the connecting cabling for connecting the lighting units 130 to the lighting cabling within the cavity 113 is long enough to allow the lighting unit to be removed from the hole 154 to

provide access to the cavity. The lighting units 130 may be specially designed for use in the beams of the present invention but preferably the holes are designed to mount standard lighting units presently in use.

Also shown in Figure 3 is a section of acoustic flooring 140 which is located on the top surface of the floor beam. This may be attached to the beam prior to installing the floor beam or it may be added once the entire floor has been constructed, allowing the acoustic flooring to be laid in larger pieces with holes cut out corresponding to those in the floor beam for the terminal boxes and air conditioning vents. The acoustic floor, which is comprised of an acoustically damping material, is added if additional acoustic damping is required between the rooms above and below the floor beam and may be instead of or in addition to conventional carpet or other floor coverings. Where necessary a layer of acoustically damping material may be attached additionally or alternatively to the lower surface of the beam.

Preferably, however, the lower surface of the floor beam is intended have a good quality finish and is left exposed without separate decorative ceiling panels. (This is referred to as a"decorative architectural soffit"). To this end the lower surface could be sculpted or provided with a texture as required. If required the lower surface could however be painted or covered with separate ceiling panels. In such cases the soffit may be provided with attachment points for the panels., Although in the above description of the floor beam 100, shown in Figure 3, the first cavity 111 is used for the air conditioning duct 125, the second cavity 112 is used for the power and IT cabling 131,134 and the gas and water pipes 132, and the third cavity is used for the lighting, alternative embodiments could be arranged differently. For example any or all of the building services could be provided in any or all of the cavities.

Figure 4 shows a preferred arrangement of a floor beam 200 with a parallelogram- shaped cross-section (as shown in Figure 2b). The connections to the power and telecommunications and IT cabling and the lighting are the same as described above except that in this case there are two rows of lighting units 230 set in holes 245 in the soffit 255. The provision of the air conditioning is slightly different. In this case the fourth cavity 214 is itself used as the air conditioning duct. A series of holes 226 evenly spaced along the floor beam are provided between the cavity 214 and the exterior of the floor beam. These holes 226 function as the vents of the air conditioning system. A vent louvre (or similar) 227 is normally provided over the hole.

In both of the above described embodiments the air conditioning is provided by a so- called"displacement ventilation system". In such a system hot or cold air is supplied from a central plant room to floor vents on each level in a building and extract air is removed from ceiling vents. Therefore the building services which typically must be provided in a floor zone include terminal boxes on the upper surface (ie. the floor of the room above the floor zone), lighting units on the lower surface (ie. the ceiling of the room below the floor zone), and air supply and extract vents on both surfaces.

Figure 5 shows how this can be achieved with the floor beam 100 of the first embodiment used in conjunction with a simple variant 101 of the floor beam 100. Floor beam 101 is similar to the floor beam 100 but the trapezium-shaped cross-section has been inverted such that the longer of the two parallel sides is now the top flange and the shorter of the two is the soffit. By using pairs of these floor beams, adjacent to one another and optionally bonded together along the join line 150, a complete floor zone is built up. The terminal boxes and lighting units in floor beam 101 are located such that they are on the correct sides respectively of the floor beam to provide the required services to the rooms above and below the floor zone. The first floor beam 100 has an air conditioning duct 125 in a cavity 111 in which the face opposite the truncated vertex of the frustro-triangular cross- section of the cavity is on the lower side of the floor beam (ie. the soffit). Holes through this face therefore connect the air extract duct 125 to ceiling vents in the room below the floor beam. The second floor beam 101 has its air supply duct 126 in a cavity 161 which is the other way up with the face opposite the truncated vertex of the frustro-triangular cross-section of the cavity on the upper side of the floor beam. Holes through this face therefore connect the air conditioning duct 126 to floor vents in the room above the floor beam. Therefore pairs of these floor beams 100,101 can simply be used to connect air conditioning ducts to vents as required to be used in conjunction with conventional displacement ventilation air conditioning systems.

The same system is equally applicable when a cavity in the floor beam is used directly as the air conditioning duct as shown in Figure 6. Floor beams 300,301 are the same as. the previously described floor beams 100,101 except that the cavities 325,326, which in floor beams 100, 101 carried the air conditioning ducts, are now themselves the channels for the air flow. Cavity 326 provides fresh air from the central plant room to the room above the floor. beam through floor vent louvres 327 and cavity 325 extracts air from the room below the floor beam through ceiling vent louvres 328. The system could also clearly work with the

parallelogram-shaped beam 200 although some modifications would be required to ensure that the correct services are provided on each side of the beams.

The so-called"fancoil"system of air conditioning can also be used with the present invention. In this system an intermediate heat transfer fluid, such as water is provided to a plurality of individual fancoil units in the floor zone instead of providing heated or cooled air directly from the central plant room. In the each of the fancoil units heat is transferred between the intermediate heat transfer fluid and the air which is circulated in the room by means of a fan mounted in the individual units. The intermediate heat transfer fluid is circulated round the individual units and returned to the central plant for re-cooling or re- heating. As shown in Figure 7, the individual fancoil units 460 can be mounted in holes 453 in a further variation of the floor beam 400 of the present invention. The units are connected to intermediate transfer fluid in-pipes 461 and out-pipes 462 which are carried in the cavity in the floor beam. Depending on the system there may be separate in-pipes and out-pipes for both heating and cooling.

Although not shown in the diagram it may be necessary to adjust the size of the beams to provide a large enough cavity to install the fancoil units. In such a case the depth of the floor zone would still be substantially smaller than the depth of the floor zones of the type previously known. Alternatively, or in addition, it may be necessary to create special openings in the floor beams which may span more than one cavity in a single beam or may span more than one beam. These special openings may require further reinforcement.

Figure 8 shows a simplified layout of a floor of a typical office building constructed according to the present invention, using in this example the floor beams 100,101 of the first embodiment. It is supported by a plurality of columns 82 which also support the floors above. There are a number of edge beams 80 and internal beams 81 which transfer the floor load to the columns. The floor beams 100,101 in turn are supported by and span between the edge beams 80 and the internal beams 81. By using alternate floor beams as shown in Figure 9 a continuous, level floor zone is built up. As also shown in Figure 9 the edge beams 80 have an inclined side face corresponding to angle of the external edge web of the floor beam 100,101. Where an edge beam is adjacent to and parallel to a floor beam 101 these two faces therefore lie alongside one another, ensuring continuity of the floor. The building shown also has some of the standard features of office buildings, namely stairwells 83 and lift shafts 84. In some cases the lift shaft 84 may support the ends of the floor beams 100,101

which are adjacent to it but it is also envisaged that in some cases beams of the type previously known, which do not provide services, may be used immediately adjacent to the lift.

Figures 10 and 11 show how, in a preferred embodiment of this aspect of the present invention, the ends of the floor beams are supported by the internal beams 81 and the edge beams 80, respectively, to which the floor beams are substantially normal. The ends of the floor beams 100,101 are formed or cut to an angle corresponding to the angle of the supporting face of the internal or edge beam. For increased strength, the ends of the floor beams 100,101 have a facing plate 92. In alternative embodiments (not shown) the ends of the beams may have an attachment member inserted in on or more of the cavities or, where it proves unnecessary, may be mounted unaltered. The floor beams are then bonded to the support face. This may be in the same manner as the floor beams are bonded to each other or by another means.

Each of the edge beams 80 and the internal beams 81 have cavities 90,91 respectively within them. The building services required in the building are routed in these cavities and connect with the cables, pipes and ducts in the floor beams through holes in the support surface 86, 87 and the facing plate 92 or, where used, the attachment member inserted in the end of the floor beam 100,101. The building services in the edge and internal beams 80,81 are connected to cables, pipes and ducts (as necessary) in vertical riser shafts, parallel to the columns, in order to connect them to the building's network of services.

Alternatively the floor beams 100,101 may supported by locating the lower surface of the floor beam directly on top of the upper surface of the internal beams 81 and edge beams 80. In addition the building services within the floor beams may be connected via cavities within partition walls.

The edge beams 80 and the internal beams 81 are preferably formed from composite materials with cavities 90,91 for carrying the services and they may be reinforced. They may also be formed from commonly used structural materials, such as reinforced concrete or steel, in which case, as described above, the services will be provided to the floor beams by another means.

An important aspect is the holes in the top surface and the soffit of the floor beams which are used to locate the terminal boxes, the lighting units and the air conditioning vents.

In a preferred option the holes are provided at regular intervals along each of the floor beams creating possible locations for terminal boxes, lighting units and air conditioning vets (both floor and ceiling3 close to any required position in the floor layout. In locations where the

holes are not required close-fitting covers can be provided to conceal the hole. Alternatively the holes may be provided only at the positions along the floor beam which are required.

The holes may be formed in the floor beam as it is being produced or may be cut into the floor beam at a later stage. This may, where necessary, be as the floor is being assembled or possibly even after the building has been completed should it prove necessary. Depending on the size of the hole, the length of the span that the floor beam is traversing, and the load that the floor beam is to cany, reinforcing may be required around the holes. This may also be added at any stage.

In a preferred method of building a structure according to the present invention the floor beams and/or edge and internal beams are fitted with power cabling, water and gas pipes, lighting units and air conditioning ducts, as necessary, to form discrete modules before being installed in the structure. These services can then be simply connected to the services network of the building as the structure is built. Once the floor beams are in place services such as structured telecommunications and IT cabling (for example optical fibres) can be drawn through the cavities to the required terminal boxes as before.

In a preferred method, emergency equipment, such as smoke detectors, heat sensors, water sprinklers and alarms, is mounted on the modules with the associated cabling and pipes prior to the modules being assembled to the structure.

The invention is however not intended to be limited to any of the above described methods and any or none of the services may be installed in the floor beams, and/or the edge and internal beams prior to the floor beams being installed in the structure.

In the preceding description reference has been made to the flooring system in its use in the construction of buildings, especially office buildings. However the invention is not limited to the construction of buildings but may also be of use in the building of any structure which contains a supported floor and contains services.