Method for determining pressure capability in conduit

1. A method for determining a pressure capability of an expanded conduit after an expansion process, whereby an original conduit is expanded, resulting in an expanded conduit, the method comprising the steps of:

(a) determining hoop strength as a function of relative wall thickness;

(b) determining Wall Thickness Ratio (WTR) by dividing a nominal wall thickness of the original conduit by the minimum wall thickness of the expanded conduit;

(c) determining long-term hydrostatic stress;

(d) applying an accelerated regression analysis to the results in step (c), yielding a Hydrostatic Design Basis (HDB); and

(e) storing, outputting, displaying or otherwise presenting the Hydrostatic Design Basis (HDB) determined in step (d).

2. The method of claim 1 , wherein the expanded conduit is manufactured from a thermoplastic material.

3. The method of claim 2 , wherein the thermoplastic material is polyvinyl chloride.

4. The method of claim 1 , wherein the original conduit is at least one of uniformly, non-uniformly and partially uniformly expanded.

5. The method of claim 1 , further comprising the step of determining pipe internal pressure in the formula: P=2St/(D 0 −t), wherein:

S =hoop tensile strength;

D 0 =average outside diameter; and

t=wall thickness.

6. The method of claim 1 , wherein the expanded conduit is oriented, the method further comprising the step of determining short-term (burst) pipe internal pressure (P) in the formula: P=(2(1879+6239×WTR)t)/D 0 −t), wherein:

D 0 =average outside diameter; and

t=wall thickness.

7. The method of claim 1 , wherein the expanded conduit is oriented, the method further comprising the step of determining long-term hydrostatic pipe internal pressure (P) in the formula: P=(2((3147.5·WTR+1069.5)/F)t)/(D 0 −t), wherein:

F=safety factor;

D 0 =average outside diameter; and

t=wall thickness.

8. The method of claim 1 , further comprising the step of determining short-term internal pipe pressure for at least one of the expanded conduit and an oriented expanded conduit based upon at least one of final outside diameter, starting thickness, minimum final thickness, hoop tensile strength, average outside diameter, wall thickness, pipe internal pressure and wall thickness ratio.

9. The method of claim 1 , further comprising the step of determining long-term internal pipe pressure for at least one of the expanded conduit and an oriented expanded conduit based upon at least one of final outside diameter, starting thickness, minimum final thickness, hoop tensile strength, average outside diameter, wall thickness, pipe internal pressure, a safety factor and wall thickness ratio.

10. The method of claim 1 , further comprising the step of plotting at least one of HDB against WTR, short-term (burst) pipe internal pressure and long-term pipe internal pressure.

11. The method of claim 10 , further comprising the step of displaying the resulting plot is a user on a display device.

12. The method of claim 1 , wherein at least one step of the method is completed by a computing device.

13. The method of claim 12 , wherein the computing device is at least one of a computer, a personal computer, a laptop, a palmtop, a personal digital assistant, a server and a networked computer.

14. The method of claim 1 , wherein at least one of the hoop strength, the relative wall thickness, the wall thickness ratio, the nominal wall thickness of the original conduit, the minimum wall thickness of the expanded conduit, pipe internal pressure, average outside diameter, wall thickness, hoop tensile strength, a safety factor, short-term (burst) pipe internal pressure and the long-term hydrostatic strength is provided to a computing device by a user utilizing an input device.

15. The method of claim 14 , wherein the input device is at least one of a keyboard, a mouse, a trackball and a device in communication with the computing device.

16. The method of claim 1 , wherein at least one of the hoop strength, the relative wall thickness, the wall thickness ratio, the nominal wall thickness of the original conduit, the minimum wall thickness of the expanded conduit, pipe internal pressure, average outside diameter, wall thickness, hoop tensile strength, the long-term hydrostatic strength, the hydrostatic design basis, short-term pipe internal pressure, long-term pipe internal pressure, projected data, projected results and projected variables is visually provided on a display device in communication with a computing device.

17. The method of claim 16 , wherein at least one of the results of the regression analysis, the wall thickness ratio, the hydrostatic design basis, the long-term hydrostatic strength, pipe internal pressure, short-term pipe internal pressure, hoop tensile strength, projected long-term hydrostatic stress, projected wall thickness ratio, pipe internal pressure, average outside diameter, wall thickness, hoop tensile strength, projected data, projected results, projected variables, and combinations thereof are plotted and presented in graphical form.

18. The method of claim 1 , further comprising the step of choosing a specifically-dimensioned conduit for a specified application based upon at least one of the hoop strength, the relative wall thickness, the wall thickness ratio, the nominal wall thickness of the original conduit, the minimum wall thickness of the expanded conduit, pipe internal pressure, average outside diameter, wall thickness, hoop tensile strength, the long-term hydrostatic strength, the hydrostatic design basis, short-term (burst) pipe internal pressure, long-term pipe internal pressure, projected data, projected results and projected variables.

19. The method of claim 1 , further comprising the step of choosing a specifically dimensioned conduit for a specified application based upon at least one of projected hydrostatic design basis and the long-term hydrostatic stress as a function of wall thickness ratio.

20. The method of claim 1 , wherein the long-term hydrostatic stress is determined by at least one of hoop testing and burst testing.

21. The method of claim 1 , wherein projected hydrostatic design basis is in the range of about 4000 and about 7100 psi.

22. A system for determining a pressure capability of an expanded conduit after an expansion process, whereby an original conduit is expanded, resulting in an expanded conduit, comprising:

means for determining hoop strength as a function of relative wall thickness;

means for determining Wall Thickness Ratio (WTR) by dividing a nominal wall thickness of the original conduit by the minimum wall thickness of the expanded conduit;

means for determining long-term hydrostatic stress;

means for determining a Hydrostatic Design Basis (HDB); and

means for storing, outputting, displaying or otherwise presenting the determined Hydrostatic Design Basis (HDB).