Issue Date: January 20, 2012
Revision Date: April 21, 2015

Leak Detection Technologies

MDleak Enhanced Leak Detection and Leak Location Method



Leak rate of 0.005 gph with PD = 100% and PFA = 0% (with pipeline secondary containment).

Leak rate of 0.005 gph with PD = 97.5% and PFA = 2.5% (pipeline direct contact to soil).

Leak Threshold

A pipeline system should not be declared tight when the chemical marker detected exceeds the background level outside of the pipeline. 


Gasoline, diesel, aviation fuel, fuel oil #4, fuel oil #6 (if between 60 to 150 degrees F), solvents, waste oil.

Cannot be used where ground-water is above the bottom of the pipe and the pipe is filled with a water-miscible product unless highly volatile evaporative chemical markers are used or pipeline is emptied and tested dry.

Pipeline Capacity

Not limited by capacity.

Waiting Time

A range from 5 to 31 days after the chemical marker is mixed throughout the containment to be tested.

The waiting period may be adjusted below or above this range when supported by "Controlled Leak Points" as described below.

Waiting time begins after chemical marker has reached all portions of the pipeline being tested.

Controlled Leak Points

"Controlled Leak Point" is a port where chemical marker is injected directly into the soil surrounding the containment to determine the rate at which chemical marker migrates through the backfill.  It can be used to demonstrate that the chemical marker will migrate through the soil to a detection point in a documented amount of time, as described in manufacturer's procedures.

Chemical Marker Dosage

Dosage of the chemical marker, either liquid or vapor, is base don containment volume, and the duration of time the inoculated product will remain within the test section.  The test period begins once the chemical marker has been mixed and distributed throughout the test section(s).

Pipelines are typically tested in an in-service operating condition; pipelines that are out of service or under construction are tested at working pressure.  Chemical marker concentration and sampling points are adjusted to meet the test specifications.

Soil Permeability

Soil permeability must readily allow chemical marker movement through the excavation backfill (greater than 1 Darcy) or the use of a controlled leak point is required.

Sampling Port

Radius of influence of each chemical marker sampling port is maximum 16 feet or a maximum separation between sampling points of 32 feet.

Pipeline must be accurately located to ensure that all pipeline surfaces are within the zone of influence of a sampling port.

Sampling ports must be installed per manufacturer's guidelines.

Horizontal sampling probes may be installed in manufactured backfill during the initial containment installation.  These probes must be installed per manufacturer's guidelines.


This method can be used to test single-walled and double-walled components for leakage to soil by sampling in the backfill or to test the primary containment integrity of a double-wall component by sampling in the interstitial space.

The tester may determine that pre or post testing is needed to establish the background level of chemical marker in the soil.

For shorter/longer test periods, for different sampling port spacing, or in soil conditions that are uniquely different from standard engineered backfill, such as water saturated frozen soil, a controlled leak point shall be installed to document the chemical marker migration period.


Leak Detection Technologies Evaluator:  Ken Wilcox Associates
2765 East Wieding Road Tel:  (816) 443-2494
Tucson, AZ 85706 Date of Evaluation:  01/07/08
Tel: 855-255-5325  


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