AU2012101957A4

AU2012101957A4 - Piping

Info

Publication number: AU2012101957A4
Application number: AU2012101957A
Authority: AU
Inventors: Darren Suell
Original assignee: DENNIS FAMILY INTELLECTUAL PROPERTY Pty Ltd
Current assignee: DENNIS FAMILY INTELLECTUAL PROPERTY Pty Ltd
Priority date: 2011-12-15
Filing date: 2012-11-26
Publication date: 2016-07-07
Anticipated expiration: 2020-11-26
Also published as: AU2012255796A1

Abstract

A method of forming a foundation slab 10 having at least one pipe 40 for conveying fluid. At least one elongate portion of the pipe is positioned within a void. A settable material is supplied to the void. The material is allowed to set to at least 5 predominantly form the slab. The elongate portion spans a horizontal distance within the set material and is embraced, and substantially restrained from at least transverse movement, by the set material. Fig. 1

Description

PIPING

FIELD OF THE INVENTION

This invention relates to foundation slabs and pipes for conveying fluid.

BACKGROUND A foundation slab is a horizontal body of material upon which a building is or can be built. Foundation slabs are usually formed of concrete. Typically the foundation slab of a single family home would be a single integral body of concrete. For larger buildings, the foundation slab is sometimes formed in separate slab portions.

Usually pipes must be routed to and from the interior of the building. The pipes include water and gas supply pipes and drains and sewers.

An existing approach to forming a foundation slab involves: 1. Leveling (or “benching”) the site. This may involve building retaining walls. 2. Setting out markers to identify where key features of the slab should be positioned. 3. Digging deep vertical holes to form piers if required. Australian building regulations specify that these holes must be inspected by a government official. 4. Positioning electrical cables in trenches and backfilling the trenches. 5. Laying respective water supply, sewerage and storm water pipes in trenches and backfilling the trenches. 6. Depositing a crushed rock base and leveling the base over the site. 7. Laying a plastic film over the crushed rock base to form a vapour barrier. 8. Setting up temporary formwork about the site. 9. Arranging permanent formwork modules known as “waffle pods” within the region bounded by the temporary formwork. 10. Positioning steel reinforcing mesh and/or bars. Typically the steel reinforcement runs along the base of the channels and a layer of mesh sits atop the waffle pods. 11. A plumber inspecting the water supply, sewerage and storm water pipes. 12. A further inspection by a government official. 13. Pouring concrete to fill a void defined by the formwork. 14. Allowing the concrete to set. 15. Removing the temporary formwork. 16. Backfilling the perimeter of the slab with earth. 17. The water supply, sewerage and storm water pipes being respectively connected to respective services pipes.

In a suburban setting service pipes are run along the street (under the road surface) and connect to each house along the street. The water supply service pipes supplies water to the houses. The sewerage and storm water pipes respectively carry sewerage and storm water away from the houses.

The inventor has identified that this method of construction has a number of drawbacks.

Forming a slab in accordance with this method typically takes five or more days.

Leveling the site and digging trenches to lay the water supply, sewerage and storm water pipes can be difficult. This is especially so when rock is encountered.

Typically there is a delay of at least a few days between the trenches being back-filled and the concrete being poured. During this time the pipes are prone to damage. This is particularly so when following the more recent approach in which a careless worker might crush the pipes by driving a vehicle over the more or less planar surface. Damage at this stage is especially problematic in that it rarely becomes evident until an occupant takes possession of their new building.

Identifying and repairing leaking pipes under a foundation slab is very difficult. By way of example, a leak might manifest as a wet patch about the building without any simple way of identifying its cause. Various complex approaches to addressing these problems have been developed, including various remote control apparatus such as directional drills for “opening” crushed pipes and remote control repair tools for sealing damaged pipes.

Moreover it is desirable to reduce the cost of a foundation slab and pipes.

It is an object of the invention to provide improvements relating to foundation slabs and pipes for conveying fluid, or at least to provide an alternative for those concerned with foundation slabs and pipes for conveying fluid.

It is not admitted that any of the information in this patent specification is common general knowledge, or that the person skilled in the art could be reasonably expected to ascertain or understand it, regard it as relevant or combine it in any way at the priority date.

SUMMARY

One aspect of the invention provides a method of forming a foundation slab, for a building, having at least one pipe for conveying fluid, the method including positioning at least one elongate portion of the pipe within a void; supplying a settable material to the void; and allowing the material to set; such that the elongate portion spans a horizontal distance within the set material and is embraced along its entire length, and substantially restrained from at least transverse movement, by the set material.

The method may further include defining the void, e.g. by positioning formwork.

The elongate portion may be positioned to run along a channel portion of the void, which channel portion is preferably defined by permanent formwork. Optionally the elongate pipe portion is positioned at an inclination for drainage.

The elongate portion may be substantially straight. The settable material may be concrete.

The elongate pipe portion preferably has a diameter greater than 50 mm; e.g. it may have a diameter of 80 mm, 90 mm or 100 mm.

Preferred forms of the method include connecting the pipe to a service pipe connected to a pipe of at least one other building. Another aspect of the invention provides a foundation slab formed in accordance with the above method.

Another aspect of the invention provides a foundation slab, for a building, having at least one pipe for conveying fluid; the slab being at least predominantly formed of set material; the pipe including at least one elongate portion spanning a horizontal distance within the set material and being embraced along its entire length, and substantially restrained from at least transverse movement, by the set material.

In preferred forms of the slab, the elongate portion runs along an elongate portion of the slab, which is most preferably defined by permanent formwork. The elongate pipe portion is preferably inclined for drainage.

The elongate pipe portion may be substantially straight. The settable material may be concrete.

In preferred forms of the slab the pipe is connected to a service pipe and the service pipe is connected to a pipe of at least one other building.

Another aspect of the invention provides a building including a slab as described above.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a cross section view of a portion of a slab in accordance with an embodiment of the invention.

DESCRIPTION OF AN EMBODIMENT

In accordance with a preferred embodiment of the invention, a foundation slab 10 is formed by first grading the ground 20 to form a planar horizontal surface. Markers are set out on the horizontal surface to locate key features of the slab. Holes to suit piers may be dug if required. Electrical cables are buried in trenches. A crushed rock base is laid and leveled, followed by an impermeable membrane to form a vapour barrier.

Temporary formwork (not shown) is positioned to define the outer periphery of the slab. Permanent formwork modules 30, known as waffle pods, are then positioned. Each waffle pod is a block of expanded polystyrene foam (or any other convenient filler material) about 1090 mm x about 1090 mm when viewed in plan. The pods 30 are arranged in a horizontal array and spaced in both horizontal directions to define two sets of spaced channels (one set being transverse to the other).

Thus the temporary formwork and the waffle pods 30 together define a void, of dimensions corresponding to the finished slab, into which concrete is receivable.

Pipes, including the pipe 40, for supplying water to and carrying water away from the interior of a building to be built atop the slab are then positioned so that their straight elongate portions (including the elongate portion of pipe 40 shown in cross section in figure 1) run along the channels defined between the pods 30. The pipes are temporarily positioned using supports (not shown) which may be similar to bar chairs or brackets.

Steel reinforcing is also positioned within the void. Typically steel would be positioned adjacent the base of the channels before the pipes are positioned. In a preferred form of the invention a layer of mesh is held above the waffle pods by bar chairs and arranged to span the array of waffle pods. As such the pipes are bracketed top and bottom by steep reinforcing.

Once positioned, the pipes are connected to short upright pipe portions using elbows and other plumbing fittings. The void is then filled with concrete and the concrete allowed to set. The temporary formwork is then removed and the perimeter of the slab may be backfilled with earth.

At this stage the embedded pipes are connect to the service pipes to convey fluid to and from the building to be built atop the slab.

As used herein, “elongate portion” refers to a portion which is much longer, say at least three times longer, than it is wide. By way of example, the elongate portion might be a 1 m portion of a 4 m x φ100 mm straight pipe. In preferred forms of the invention, the elongate pipe portion is more than 5 m long for connecting fixtures inside the building to features (e.g. drains) outside the building.

The pipes carrying water away from the interior of the building are inclined at an angle of at least about 1 in 60 downward from the horizontal so that the water carried thereby drains without pooling.

The pipes are positioned above the floor of the void (formed by the ground in this embodiment) such that the liquid concrete encircles the pipes to form an integral body of material embracing each pipe. When the concrete has set, the pipes are embedded and fixed within the concrete. The pipes are carried within elongate tubular voids formed in the concrete, which tubular voids conform to the exterior of the pipes (or any lagging carried by the pipes).

When set, the surrounding concrete forms a tubular structure to guard the pipes against damage during construction and during the life of the building. Byway of example, the invention is thought to minimise the occurrence of blockages, caused by invasive tree roots, and fracturing caused by ground movement. Minimum “wall thicknesses” of concrete of 85 mm atop the pipe and 150 mm below and beside the pipe are thought desirable.

The surrounding concrete also serves as a secondary containment for the water carried in the pipes whereby water leaking from the pipes tends to track along the exterior of the pipes to an exposed portion of the pipe projecting from the slab. This is helpful when locating a source of a leak.

Upright pipe portions visible above the slab are similar to the upright pipe portions presented when a slab is formed using existing methods. Thus, according to preferred forms of the invention, subsequent connection of the embedded pipes via their upright pipe portions to fixtures such sinks, showers, basins, toilets, etc can proceed in conventional fashion.

The pipe 40 of this embodiment is about 100 mm in diameter. Other common pipe sizes include 40, 50, 80 and 90 mm. Preferred forms of the invention are compatible with conventional PVC pipes.

The temporary formwork is high enough that when filled the slab 10 has a thickness of about 385 mm above the ground. The slab 10 includes an about 85 mm to about 100 mm thick portion 12 atop the pods 30 and elongate formations 14 defined by the spaced channels. In this embodiment, the pipe 40 sits below the portion 12 and runs along and within an elongate formation 14.

The depth of the elongate formation 14 is selected to provide adequate strength without consuming excessive amounts of concrete. Long lengths of inclined pipe may have a fall greater than can be accommodated in an elongate formation 14 so dimensioned. In this case, prior to the concrete being poured, the ground 20 may be locally excavated in the vicinity of the lower portions of the pipe to downwardly extend the elongate formation 14 to fully embrace the pipe.

In summary, forming a slab in accordance with a preferred form of the invention involves: 1. Leveling (or “benching”) the site. This may involve building retaining walls. 2. Setting out markers to identify where key features of the slab should be positioned. 3. Digging deep vertical holes to form piers if required. 4. Positioning electrical cables in trenches and backfilling the trenches. 5. Depositing a crushed rock base and leveling the base over the site. 6. Laying a plastic film over the crushed rock base to form a vapour barrier. 7. Setting up temporary formwork about the site. 8. Arranging permanent formwork modules known as “waffle pods” within the region bounded by the temporary formwork. Each waffle pod is a block of expanded polystyrene foam (or any other convenient filler material) about 1090 mm x about 1090 mm when viewed in plan. The waffle pods are arranged in an array and spaced to define a grid of perpendicular channels. 9. Positioning water supply, sewerage and storm water pipes to run along the channels and positioning steel reinforcing mesh and/or bars. Typically the steel reinforcement runs along the base of the channels and a layer of mesh sits atop the waffle pods. 10. Pouring concrete to fill a void defined by the formwork. 11. Allowing the concrete to set. 12. Removing the temporary formwork. 13. Backfilling the perimeter of the slab with earth. 14. The water supply, sewerage and storm water pipes being respectively connected to respective services pipes.

Following this preferred form of the invention a slab can be formed in only four days and expenses such as digging trenches through rock for the water pipes, and the plumber returning to inspect the pipes can be avoided.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A method of forming a foundation slab, for a building, having at least one pipe for conveying fluid, the method including positioning at least one elongate portion of the pipe within a void; supplying a settable material to the void; and allowing the material to set; such that the elongate portion spans a horizontal distance within the set material and is embraced along its entire length, and substantially restrained from at least transverse movement, by the set material; wherein the positioning the elongate portion includes positioning the elongate portion to run along a channel portion of the void.
2. The method of claim 1 wherein the channel portion is defined by permanent formwork.
3. The method of claim 1 wherein the elongate pipe portion has a diameter greater than 50 mm.
4. A method of forming a foundation slab, for a building, having at least one pipe for conveying fluid, the method including positioning at least one elongate portion of the pipe within a void; supplying a settable material to the void; and allowing the material to set; such that the elongate portion spans a horizontal distance within the set material and is embraced along its entire length, and substantially restrained from at least transverse movement, by the set material; wherein the elongate pipe portion has a diameter greater than 50 mm.
5. The method of claim 3 or 4 wherein the elongate pipe portion has a diameter of 80 mm, 90 mm or 100 mm.
6. The method of any one of claims 1 to 5 including connecting the pipe to a service pipe connected to a pipe of at least one other building.
7. A method of forming a foundation slab, for a building, having at least one pipe for conveying fluid, the method including positioning at least one elongate portion of the pipe within a void; supplying a settable material to the void; allowing the material to set; and connecting the pipe to a service pipe connected to a pipe of at least one other building; such that the elongate portion spans a horizontal distance within the set material and is embraced along its entire length, and substantially restrained from at least transverse movement, by the set material.
8. The method of any one of claims 1 to 7 further including defining the void.
9. The method of claim 8 wherein the defining the void includes positioning formwork.
10. The method of any one of claims 1 to 9 wherein the positioning the elongate portion includes positioning the elongate portion at an inclination for drainage.
11. The method of any one of claims 1 to 10 wherein the elongate portion is substantially straight.
12. The method of any one of claims 1 to 11 wherein the settable material is concrete.
13. A foundation slab formed in accordance with any one of claims 1 to 12.
14. A foundation slab, for a building, having at least one pipe for conveying fluid; the slab being at least predominantly formed of set material; the pipe including at least one elongate portion spanning a horizontal distance within the set material and being embraced along its entire length, and substantially restrained from at least transverse movement, by the set material; wherein the elongate portion runs along an elongate portion of the slab.
15. The slab of claim 14 further including permanent formwork defining the elongate portion of the slab.
16. The slab of claim 14 or 15 wherein the elongate pipe portion has a diameter greater than 50 mm.
17. A foundation slab, for a building, having at least one pipe for conveying fluid; the slab being at least predominantly formed of set material; the pipe including at least one elongate portion spanning a horizontal distance within the set material and being embraced along its entire length, and substantially restrained from at least transverse movement, by the set material; wherein the elongate pipe portion has a diameter greater than 50 mm.
18. The slab of claim 16 or 17 wherein the elongate pipe portion has a diameter of 80 mm, 90 mm or 100 mm.
19. The slab of any one of claims 14 to 18 wherein the pipe is connected to a service pipe and the service pipe is connected to a pipe of at least one other building.
20. A foundation slab, for a building, having at least one pipe for conveying fluid; the slab being at least predominantly formed of set material; the pipe including at least one elongate portion spanning a horizontal distance within the set material and being embraced along its entire length, and substantially restrained from at least transverse movement, by the set material; wherein the pipe is connected to a service pipe and the service pipe is connected to a pipe of at least one other building.
21. The slab of any one of claims 14 to 20 wherein the elongate pipe portion is inclined for drainage.
22. The slab of any one of claims 14 to 21 wherein the elongate pipe portion is substantially straight.
23. The slab of any one of claims 14 to 22 wherein the settable material is concrete.
24. A building including the slab of any one of claims 14 to 23.
25. A slab substantially as herein described with reference to figure 1.