THE APPLICATION OF INLINE LEAK DETECTION TECHNOLOGY IN LARGE DIAMETER PIPELINES: STATISTICS AND CASES STUDIES. P.

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1 THE APPLICATION OF INLINE LEAK DETECTION TECHNOLOGY IN LARGE DIAMETER PIPELINES: STATISTICS AND CASES STUDIES P.Pina & JF Prinsloo 1

2 Should we really address trunk main leakage? Water mains rarely leak Water main losses are less than 3% - you probably have bigger problems to worry about Water main leaks will find you, you don t have to find them! Conventional leak methods are effective for large diameter pipes 2

3 Inline Acoustic Tools Free Swimming Tethered 3

4 SmartBall Inline Leak and Gas Pocket Detection 4

5 Sahara Inline Leak and Gas Pocket Detection Surface 5

6 International Average Leakage Rates per 100km of Inspected Pipe (more than 8000km) DI 43 Steel 33 BWP 13 PVC 36 AC 51 PCCP 21 CI

7 International Average Leakage Rates per 100km of Inspected Pipe 95 leaks per 100 km 5,679 Leaks 5,974 km 7

8 Geografical Distribution 62 leaks per 100 km 150 leaks per 100 km 60 leaks per 100 km 38 leaks per 100 km 23 leaks per 100 km 8

9 Leaks per 100 miles Leaks Per 100 Miles Inspected by Size Pipe Diameter (in) Note: Bubble size is proportional to amount of pipe inspected at that diameter Source: Free Swimming database

10 Water main losses are less than 3% Gwinnett County South West Florida Utility No. 3 Dist. Mains Trans. Mains Dist. Mains Trans. Mains Dist. Mains Trans. Mains Distance (km) 3,900 4,700 7,100 No. of Leaks 92% 8% 91% 9% 93% 7% Avg. leak size (LPM) Total leakage 51% 49% 13% 87% 63% 37% Bulk Pipelines have High Value leaks i.e. high pressure and/or large volume leaks Majority of high pressure/large leaks do not surface - 75% of detected leaks did not show surface signs 10

11 Water main leaks will find you, you don t have to find them! Pipe Buried Under Pavement Permeable Soil Conditions Low Pressure Leaks / Deeply Buried Pipes High Pressure Leaks (12 Bar) Under Shallow Soil Cover (1.5 m) 11

12 Water main leaks will find you, you don t have to find them! 12

13 Conventional leak methods are effective 13

14 Case Study NRW project in Malaysia 14

15 Case Study Metropolitana Milanese 9 km Steel 1200mm Unknown condition Leak detection as a screening aproach 24 leaks detected grouped in 3 zones 15

16 Leak detection for Pipeline Condition Assessment? Aging infrastructure is a key concern The best-in-class renewal programs only address 1% of the system per year. Pipeline renewal programs are typically age & failure based Age Rarely Correlates With Condition (Water Research Foundation) 70% To 90% Of Replaced Pipelines Have Remaining Life (US EPA) 16

17 Leak Before Break Most leaks can be considered as defects as the line remains in service until such time as it is repaired. Leaks in pipe walls can be important, because they are likely to indicate perforation in the pipe wall, which in some mains is considered to lead to structural failure. Stress raisers around the pitting create high local stress leading to fracture EPA 2009 Advances in fracture mechanics allowed a better understanding of piping behaviour and it has been demonstrated that postulated small through-wall flaws could be detected by leakage long before the flaws could grow to unstable sizes which might cause a catastrophic break. International Atomic Energy Agency 1993 This test provides evidence of leaks happening before a break Department of Civil Engineering, Monash University, Melbourne, Australia 17

18 Case Study Metropolitana Milanese 9 km Steel 1200mm Unknown condition Leak detection as a screening aproach 24 leaks detected grouped in 3 zones 18

19 Case Study Rand Water 16 km PCCP 900mm 19

20 Conclusions Large diameter pipes do leak, volumes are significant, and most of the times difficult to detect; Traditional methods are not always effective; Leak detection shouldn t be justified only for NRW reasons but for risk assessment as well

21 Thank You! Please visit us at Xylem s Stand Pedro.Pina@puretechltd.com kobus.prinsloo@ssis.co.za 21