AU2006273041A1

AU2006273041A1 - Fire retardant elevated floor structure

Info

Publication number: AU2006273041A1
Application number: AU2006273041A
Authority: AU
Inventors: Alan Gordon Franklin; Kevin Allan Saunders
Original assignee: Individual
Current assignee: Individual
Priority date: 2005-07-29
Filing date: 2006-07-24
Publication date: 2007-02-01
Also published as: NZ541586A; WO2007013818A1

Description

WO 2007/013818 PCT/NZ2006/000186 FIRE RETARDANT ELEVATED FLOOR STRUCTURE FIELD OF THE INVENTION The present invention relates to a fire retardant elevated floor structure. 5 BACKGROUND Elevated floor structures for buildings are, in many cases, designed to meet certain fire safety standards. In particular certain fire safety standards have specified that an elevated floor structure needs to be resistant or retardant to the progress of 10 fire from below to the upper portion of the floor structure for a certain minimum duration. For example standard AS15304-1997 is a standard in respect of such a fire rating. The elevated floor structures where fire safety considerations are paramount include those floor structures used in public storage facilities or warehousing. 15 Public storage facilities are relatively prevalent in many cities. Members of the public are able to lease a storage cubical to securely store their personal possessions. Storage facilities may include the provision of cubicles on multi levels. As such, elevated floor structures are used. Figures 1, 2 and 3, show a partial perspective view of an elevated floor 20 structure. With reference to Figure 1, an elevated floor structure without any additional fire resistant cladding or panelling is shown. An elevated floor 1 is supported on joists 2 which in turn is supported by at least one or more bearers 3 which for example are supported by posts 4 or hung from adjacent wall structures. A fire emanating from below the elevated floor 1 can directly and immediately 25 impinge on the lower surface of the floor. The floor 1 is usually defined by a particle board, sufficiently strong to support the weight that may be placed on top. However particle board on its own may not be sufficiently resistant to the progress of fire from below to the upper surface of the floor to meet the standards. The thickness of the particle board can be increased to increase the resistance to fire 30 migrating from below to above the panel. However an increase in particle board WO 2007/013818 PCT/NZ2006/000186 -2 thickness increases the cost of the particle board and also makes their handling more difficult during construction. With reference to Figure 2 there is shown a common construction for enhancing fire resistance to meet certain fire safety standards. In the example of 5 Figure 2, a fire retardant panelling 5 is fastened below the floor panel 1, joist 2 and bearer 3. The fire retardant panelling 5 provides a first barrier to the migration of fire from below the floor 1 to above the floor 1. The disadvantage of the provision of the fire retardant panelling 5 both below the bearer 3 and the joist 2 is that it creates a wasted cavity space between the fire retardant panelling 5 and the floor 1 10 and it restricts or limits the convenient access to any building services which may be provided below the floor panel 1. Also this construction can be quite inconvenient to incorporate in the elevated floor structure in that the panelling 5 needs to be cut to take into account rebates 6 at the posts 4. In addition occupants of cubicles may not necessarily take great care in moving possessions into and out of a cubicle. The 15 assembly of the fire retardant structure shown in Figure 2 has the limitation of the fire retardant panelling 5 being prone to damage. A person handling an object within the cubicle can puncture the fire retardant panelling 5 thereby affecting the integrity of the overall structure which in many cases can result in the structure no longer meeting the fire rating standards. 20 Figure 3 shows an alternative arrangement to that of Figure 2 wherein the fire retardant panelling 5 is positioned not below the bearer 3 but adjacent the bearers 3 and fastened directly against the joists 2. This still does not offer a solution to most of the above disadvantages discussed with reference to Figure 2. A further disadvantage of the configuration shown in Figures 2 and 3 is that 25 the fire retardant panelling will include joins 7 where adjacent fire retardant panels abut each other. These joins are normally a location where propagation of a fire is initiated from below the fire retardant panel to above the panel structure. These joins can be capped by a capping device such as for example shown in PCT/NZ2004/000300. This capping adds another step to the fabrication of 30 elevated floor structures of a kind which can meet the fire rating standards.

WO 2007/013818 PCT/NZ2006/000186 -3 Accordingly there is a need for an elevated floor structure which addresses the abovementioned disadvantages. It is therefore an object of the present invention to provide an elevated floor structure which addresses the abovementioned disadvantages or which will at least provide the public with a useful 5 choice. In this specification where reference has been made to patent specifications and other external documents, this is generally for the purpose of providing a context for discussing the features of the invention. Unless specifically stated otherwise, reference to such external documents is not to be construed as an 10 admission that such documents, or such sources of information, in any jurisdiction, are prior art, or form part of the common general knowledge in the art. BRIEF DESCRIPTION OF THE INVENTION Accordingly in a first aspect the present invention consists in a fire retardant 15 elevated floor structure comprising, a plurality of parallel and spaced apart joists supported by support means, at least one fire retardant panel supported by said joists, at least one floor panel located above said fire retardant panel. Preferably said floor panel is contiguous said fire retardant panel. 20 Preferably said -floor panel is immediately adjacent and in contact with said fire retardant panel. Preferably said floor panel is a particle board panel. Preferably said floor panel is a plywood. Preferably said fire retardant panel is of quadrilateral shape having at least 25 two parallel and opposed edges. Preferably said fire retardant panel is supported on said joists such that said two parallel and opposed edges are located contiguous a said joist. Preferably said fire retardant panel has each of its said two parallel and opposed edges positioned parallel to and located ontop of a respective said joist. 30 Preferably said fire retardant panel is gypsum based panel.

WO 2007/013818 PCT/NZ2006/000186 -4 Preferably said fire retardant panel is a gypsum based panel with specific fire rating characteristics. Preferably said floor panel is adhered to said fire retardant panel. Preferably said floor structure does not include a lining provided at or below 5 the lower most edges of said joists. Preferably said support means include at least one bearer on top of which said joists are positioned. Preferably said support means also includes at least one standing post at or towards the upper distal end of which said bearer is affixed. 10 Preferably said joists are of a height of between 170 and 230 mm. Preferably said joists are 200mm high and 50mm wide. Preferably said joists are 200mm high and 75mm wide. Preferably each said joist is of a single piece of material Preferably said material is steel. 15 Preferably said material is wood. Preferably each said joist is of a composite construction comprising a beam of steel and a beam of wood located ontop of the beam of steel. In a second aspect the present invention consists in a building which includes a fire retardant elevated floor structure as herein before described. 20 BRIEF DESCRIPTION OF THE DRAWINGS A preferred form of the present invention will now be described with reference to the accompanying drawings in which, Figure 4 is a perspective view of assembly of an elevated floor structure of a 25 preferred form of the present invention. DETAILED DESCRIPTION OF THE INVENTION A floor structure such as that generally defined by number 100, comprises of floor panels 11 which provide the supporting surface onto which people and items 30 can be supported. The floor panels 11 may consist of a particle board panel such as for example medium density particle board. Such floor panels may for example be WO 2007/013818 PCT/NZ2006/000186 -5 of a thickness of approximately 20 mm and may abut each other along the joins 22 as for example shown in Figure 4. Beneath and preferably contiguous with the floor panels 11, is a fire retardant panel or panels 15. The fire retardant panel or panels 15 are preferably coextensive with the floor panels 11. Certainly the fire retardant 5 panels 15 are of the same or greater extent than the floor panels 11 at where the floor panels can be exposed to fire and heat from below. The fire retardant panels may alternatively not be completely contiguous with the floor panels 11 and intermediate panels or plies or film or adhesive or similar can interpose the floor panels 11 and the fire retardant panels 15. Preferably the fire retardant panels 15 are 10 a gipsum based panel. For example products known by the trade mark Fireline TM which is a gipsum based product made by Winstone Wallboards Limited. The nature of the fire retardant panels 15 is preferably such that they would provide additional and/or a higher fire resistance than the floor panels 11. Placing the fire retardant panels 15 intermediate of any source of fire and the floor panels 11 will 15 enhance the fire retardancy of the floor structure. The fire retardant panels 15 are preferably directly or alternatively indirectly supported on the joists 12. The joists 12 are preferably not of a standard 150 x 50 mm joist sizing. The joists 12 are preferably of a greater height than standard 150 x 50 mm timber joists most commonly used. The joists 12 are preferably of a height within 30 mm of a 20 height of 200 mm. In the preferred construction the joists 12 are able to be directly exposed to a fire below the floor structure without having some form of protection from fire retardant panelling 5 as is the case for example in Figures 2 and 3. As such, this requires for the joists to be of a more substantial size than the standard joist size of 25 150 x 50 mm in order to improve the fire safety rating of the structure. This is so because as well as fire retarding properties by the floor panels 11, the structural integrity of the elevated floor needs to be maintained for a minimum duration. Such integrity can be affected by the decrease in integrity of the joists 12. The joists may be of a metal or of a timber joist. An increase in their size from the standard 150 x 30 50 mm joist is preferable in order for their integrity to remain sufficient for the WO 2007/013818 PCT/NZ2006/000186 -6 minimum duration as specified by certain fire rating. Preferably they are 200 mm in height. Preferably they are 75 mm wide. With reference to Figure 4, the fire retardant panels 15 are preferably placed so as to provide their abutting joins 17 in a manner so that they are located on top 5 of the joists 12. With appropriate joist spacing and consistent fire retardant panel widths, the edges of each of the fire retardant panels can be positioned to extend along the length of the joists and supported on top of the joist. This therefore negates the need for any such abutting edges 17 of adjacent fire retardant panels to being capped by an additional capping member. In this instance the joists provide 10 effectively such capping to prevent exposure of the abutting edges 17 of the fire retardant panels to any fire or heat from below.

Claims

1. A fire retardant elevated floor structure comprising, a plurality of parallel and spaced apart joists supported by support means, at least one fire retardant panel supported by said joists, 5 at least one floor panel located above said fire retardant panel.

2. A fire retardant elevated floor structure as claimed in claim 1 wherein said floor panel is contiguous said fire retardant panel.

3. A fire retardant elevated floor structure as claimed in claim 1 or 2 wherein said floor panel is immediately adjacent and in contact with said fire retardant panel. 10

4. A fire retardant elevated floor structure as claimed in any one of claims 1 to 3 wherein said floor panel is a particle board panel.

5. A fire retardant elevated floor structure as claimed in any one of claims 1 to 3 wherein said floor panel is a plywood.

6. A fire retardant elevated floor structure as claimed in any one of claims 1 to 5 15 wherein said fire retardant panel is of quadrilateral shape having at least two parallel and opposed edges.

7. A fire retardant elevated floor structure as claimed in claim 6 wherein said fire retardant panel is supported on said joists such that said two parallel and opposed edges are located contiguous a said joist. 20

8. A fire retardant elevated floor structure as claimed in claims 6 or 7 wherein said fire retardant panel has each of its said two parallel and opposed edges positioned parallel to and located ontop of a respective said joist.

9. A fire retardant elevated floor structure as claimed in any one of claims 1 to 8 wherein said fire retardant panel is gypsum based panel. 25

10. A fire retardant elevated floor structure as claimed in any one of claims 1 to 9 wherein said fire retardant panel is a gypsum based panel with specific fire rating characteristics.

11. A fire retardant elevated floor structure as claimed in any one of claims 1 to 10 wherein said floor panel is adhered to said fire retardant panel. WO 2007/013818 PCT/NZ2006/000186 -8

12. A fire retardant elevated floor structure as claimed in any one of claims 1 to 11 wherein said floor structure does not include a lining provided at or below the lower most edges of said joists.

13. A fire retardant elevated floor structure as claimed in any one of claims 1 to 5 12 wherein said support means include at least one bearer on top of which said joists are positioned.

14. A fire retardant elevated floor structure as claimed in claim 13 wherein said support means also includes at least one standing post at or towards the upper distal end of which said bearer is affixed. 10

15. A fire retardant elevated floor structure as claimed in any one of claims 1 to 14 wherein said joists are of a height of between 170 and 230 mm.

16. A fire retardant elevated floor structure as claimed in any one of claims 1 to 15 wherein said joists are 200mm high and 50mm wide.

17. A fire retardant elevated floor structure as claimed in any one of claims 1 to 15 15 wherein said joists are 200mm high and 75mm wide.

18. A fire retardant elevated floor structure as claimed in any one of claims 1 to 17 wherein each said joist is of a single piece of material

19. A fire retardant elevated floor structure as claimed in any one of claims 1 to 18 wherein said material is steel.

20 20. A fire retardant elevated floor structure as claimed in any one of claims 1 to 18 wherein said material is wood.

21. A fire retardant elevated floor structure as claimed in any one of claims 1 to 17 wherein each said joist is of a composite construction comprising a beam of steel and a beam of wood located ontop of the beam of steel. 25

22. A building which includes a fire retardant elevated floor structure as hereinbefore claimed.