1. Pipeline design in high consequence areas
Compliance with AS 2885 in an area subject to encroachment

2. PIPELINE DESIGN IN HIGH CONSEQUENCE AREAS
General principles
Specific requirements
Application of principles & requirements

3. GENERAL PRINCIPLES 0.2 BASIS OF THE AS 2885 SERIES OF STANDARDS
The fundamental principles …are as follows:
(a) … ensure the safety of the community, protection of the environment and security of supply.
(b) … designed and constructed to have sufficient strength, ductility and toughness to withstand all planned and accidental loads … during … operation.
etc.

4. GENERAL PRINCIPLES Appendix G ALARP Costs disproportionate to benefits
What else can I do?
Why haven’t I done it?

5. DESIGN Specific requirements
4.7 SPECIAL PROVISIONS FOR HIGH CONSEQUENCE AREAS
4.7.1 General
Locations …where special provisions are necessary to limit the consequence of pipeline failure on the community or the environment.
For gas pipelines, the consequence is likely to result from ignition of the fluid released.
For oil pipelines the environmental consequence may be dominant.

6. DESIGN Specific requirements
4.7.2 No rupture
Residential (T1), High Density (T2) Industrial (I), Heavy Industry (HI) and Special (S)
Design such that rupture is not a credible failure mode.
Either:
The hoop stress does not exceed 30% of SMYS or;
(b) Critical defect length at MAOP is not less than 150% of the axial length of the largest equivalent defect produced by the threats identified in that location.
Definitions of T1 etc are in 4.3 CLASSIFICATION OF LOCATIONS

7. DESIGN Specific requirements
4.7.3 Maximum discharge rate
All Locations
Consideration shall be given to … limiting the maximum discharge rate..
High Consequence Locations
.. jet fires or vapour cloud fires … maximum allowable discharge rate shall be determined and shall be approved.
Flammable gases, HVPLs & liquids with flash point < 20°C
… maximum allowable discharge rate shall not exceed
10 GJ.s-1 in Residential, Industrial and Sensitive locations or
1 GJ.s-1 in High Density locations. .

8. DESIGN Application of principles & requirements
X80 pipe with 0.8 design factor
City gate with 15.3 MPa upstream and 10.2 MPa downstream
Minimum pressure thickness, MPa 4.7 mm
Minimum pressure thickness, MPa 7.1 mm
Reasonable penetration resistance (B=1) mm
Absolute penetration resistance (B=1.3) mm
No rupture, MPa 8.4 mm
No rupture, MPa mm
Rural areas upstream of city gate mm
Rural areas downstream of city gate (if any) mm
Elsewhere downstream of city gate mm
T2 or sensitive areas mm

9. DESIGN Application of principles & requirements
T1 DOWNSTREAM OF CITY GATE (10.2 MPa, 8.4 mm)
No Rupture
OK ?
Energy Release Rate
Maximum credible hole size?
Excavator (B=1) ?
Borer?????
Release rate?
< 10 GJ.s-1?

11. Energy Release Rates (GJ.s-1)
1 MPa
2 MPa
3 MPa
5 MPa
7 MPa
10 MPa
25 mm
0.05
0.09
0.14
0.23
0.32
0.46
50 mm
0.18
0.37
0.55
0.92
1.29
1.85
100 mm
0.74
1.48
2.22
3.69
5.17
7.39
150 mm
1.66
3.32
4.99
8.31
11.63
16.62
250 mm
4.62
9.23
13.85
23.08
32.31
46.16

12. DESIGN Application of principles & requirements
T2 DOWNSTREAM OF CITY GATE (10.2 MPa, 11.0 mm)
No Rupture OK
Energy Release Rate
Maximum credible hole size?
Excavator (B=1.3) – N/A
Borer?????
Release rate?
< 1 GJ.s-1?

13. Compliance with AS 2885 in an area subject to encroachment
General principles - unchanged
Specific requirements
Application of principles & requirements

14. ENCROACHMENT Specific requirements
4.7.4 Change of Location Class
If location becomes Residential, High Density, Industrial, Heavy Industry or Sensitive , must
Do safety assessment
Implement additional measures
Demonstrate risk of rupture is ALARP.
Must consider
MAOP reduction
Pipe replacement
Pipeline relocation
Modification of land use
Extra physical and procedural measures
Must demonstrate
Cost of alternative is grossly disproportionate to the benefit.

15. ENCROACHMENT Application of principles & requirements
R2 DOWNSTREAM OF CITY GATE CHANGES TO T1
No Rupture ?
NOT OK (Wall is 4.7 mm, need 8.4mm for no rupture at 10.2 MPa)
Risk of Rupture ALARP?
(a) Reduce MAOP?
(b) Replace pipe?
(c) Relocate Pipe?
(d) Modify land use?
(e) Improve protection measures?

16. ENCROACHMENT Application of principles & requirements
Highett Gasworks
2.8 MPa assets below ground
Courthouse under construction
Land adjacent to regulator pits to be used for medium rise residential development

26. ENCROACHMENT Application of principles & requirements
Melbourne Docklands
Former West Melbourne Gasworks
2.8 MPa assets above and below ground
MAOP maintained
Some assets relocated
Remaining assets buried
Notification zone around regulator pits
Restrictions on building and other uses

27. QUESTIONS?