High Sensitivity External Leak Detection for Liquid Fuel Pipelines

David Parman P.Eng.

Ken McCoy

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Pipeline Leak DetectionThe Problem:

How can we minimize environmental damage caused by small leaks in liquid fuel pipelines that go unnoticed for long periods?

The Solution:

High Sensitivity External Leak Detection (HSELD)

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What is an HSELD system?

• A system that operates independently of the pipeline

• A system that directly detects leaked liquid using a continuously distributed, high sensitivity sensor

• A system that monitors its own integrity and checks for leaks on a 24/7 basis

• A system that compliments existing flow based leak detection to minimize your leak risk exposure

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Periodic inspection and testing

• Periodic tightness testing

• Right of way over-flights / Line Patrol

• Smart pigs• Public discovery

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0.001 0.01 0.1 1

Leak Rate (% of flow rate)

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Periodic Inspections

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Environmental Protection Risk

At RISK !

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SCADA (Flow Based) Leak Detection

Detection time

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0% 1% 2% 3% 4% 5% 6%

Leak rate (% of flow)

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• Response time is faster for higher leak rates

• Greater leak sensitivity leads to more risk of false alarms

• End User experience indicates good performance only down to about 1~2% of flow

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Spill size increases for slower leaks

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0.01 0.1 1 10Leak Rate (% of flow rate)

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At RISK !

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Combining SCADA with periodic testing helps but…

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Leak Rate (% of flow rate)

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HSELD

SCADA

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Environmental Protection Gap

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At Risk area is substantially reduced by HSELD

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External Direct Measurement

Installed into PVC well screen pipe

High Sensitivity sensor cable

Positioned alongside the pipeline

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How it works

Animation based on 10 liter/hour leak rate (0.001% of flow), 66% solids

Time (hours)

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Detection at 21 hours

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Field demonstrationTests demonstrate TT5000 detects milliliters of fuel floating on water.

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Test results

Sample 1 Water Only

Sample 2Direct Fuel

Sample 3Sensor in sand

Sample 4Sensor in PVC

Sample 5Surface Test

Sample 6Water/Fuel Mix Test

Start Time 11:15 12:07 12:12 12:12 12:58 13:59

Start Temperature 15.5C 15.5C 15.5C 15.5C 15.5C 15 C

Alarm Time NO ALARMBy 18:30

13:13 13:24 13:35 14:16 15:15

Ending Temperature 15 C 15 C 15 C`

15 C 15 C 15 C

Elapsed Time 7:15 1:06 1:12 1:23 1:18 1:16

Total Fuel Used 1 liter H20 1 liter Jet A 8 liters Jet A 8 liters Jet A 10 cl Jet A poured into standing water puddle

Bucket packed with sand, 1 liter of Jet A at the bottom, water added to saturation

Fuel Rate:Amount / Interval

All at once All at Once 1 liter/ 10 min 1 liter/ 10 min

All at once All at Once

Alarm Panel Leak Location

N/A 1 m 9 m 9 m N/A 1 m

Measured Distance to Leak

N/A 1 m 9 m 9 m N/A 1 m

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Wilcox test details

Soil Type and Condition Water Table

Leak Position Time to Alarm

Location of Sensor Alarms

Course, Damp sand Above pipe

Above pipe @ center of test bed

5h 39m 6h 27m

10 o’clock@ 4 ft 12 o’clock@ 6 ft

Course, damp sand None Bottom of pipe@ center of test bed

6 h, No additional alarms during the 9 day leak

7 o’clock@5 ft

Fine, dry sandy soil None Bottom of pipe@ center of test bed

8 days No additional alarms during the 21 day leak

7 o’clock@ 7 ft.

Fine wet soil At bottom of pipe

Bottom of pipe@ center of test bed

2 h 3d 21 h

7 o’clock@ 5 ft. 10 o’clock@ 6 ft.

Fine, wet sandy soil Above pipe

Bottom of pipe@ center of test bed

1 d 12 h 12 o’clock@ 8 ft. (approx. center of tank)

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Project Design Considerations

• Trench style / construction

• Soil type

• Ground water conditions

• Degree of environmental protection required

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Trench Type

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Ground water considerations

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• Alongside buried single wall pipelines

• Around buried valves

• Under above ground storage tanks

• On airport hydrant fueling systems

• Anywhere you need to reduce risk in High Consequence Areas

Where can you use HSELD systems?

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AST Applications

Typical plan view

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Buried Valves and Manifolds

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Cross Country Pipelines

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Pipeline Project Installation

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Installation layout for pipeline

External Modbus Link to SCADA

Circuit 1 Circuit 2 Circuit 3 Circuit 4 Circuit 5 Circuit 6

120 VAC

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Airport Hydrant Fueling Systems

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Installation layout for airport hydrant fueling system

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Regulatory Considerations

• Current regulations do not typically mandate leak detection to the level of HSELD protection

• API 1160 recognizes HSELD• Some environmental agencies have

formally recognized HSELD system• Public N.I.M.B.Y. campaigns are resulting

in greater efforts by operators to exceed regulatory requirements

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Florida State Approval

“…TraceTek TT5000leak detection system for single-walled underground bulk product piping will provide environmental protection substantially equivalent to that provided by compliance with the requirements established in Rules…”

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Third Party ValidationThird party testing of TT5000 “direct bury” system by Ken Wilcox Associates demonstrates that TraceTek works in single wall pipeline applications with Jet Fuel .

“In conclusion it must be noted that proper installation and positioning of the sensor, taking into account the local site conditions, is critical to reliable detection of leaks.”

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Summary

… fills the gap between SCADA and periodic testing

… Provides 24/7 environmental and system integrity monitoring

… Reduces emergency response time by pinpointing leak location

… Has been tested, proven and accepted by environmental authorities

… Substantially reduces operator risk in high consequence areas

TraceTek High Sensitivity External Leak Detection…