Issue Date: July 30, 2019

Hansa Consult of North America, LLC

HCNA Pressure Step Leak Detection System, Version 2.2

Line Leak Detection Method for Airport Hydrant and Field Constructed Systems


Leak rate of 0.00078% of line volume per hour in the pipeline segment being tested with PD > 95% and PFA < 5%.

Leak Threshold

0.00039% of line volume per hour.
A pipeline system should not be declared tight if the test results indicate a loss that equals or exceeds the threshold.


Gasoline, diesel, aviation fuel, fuel oil #4, solvents, waste oil, biodiesel B6-B20 meeting ASTM D7467, biodiesel B100 meeting ASTM D6751.


System tests either single or double-walled fiberglass or steel piping.

Pipeline Capacity

The HCNA 3rd party certified minimal detectable leak rate for large diameter pipeline systems (airport hydrant systems) is listed in the table below by maximum test section volume.

Leak Detection Rate Per Test Section Volume
(EPA maximum allowable/HCNA 3rd party certified)


Test Section Volume

EPA Semiannual Test-
Leak Detection Rate Not To Exceed
(Gallons Per Hour)

EPA Annual Test-
Leak Detection Rate Not To Exceed
(Gallons Per Hour)

HCNA 3rd party certified minimum detectable leak rate. (Gallons Per Hour)


5,000 to 25,000





25,001 to 50,000





50,001 to 75,000





75,001 to 100,000





101,000 to 125,000





125,001 to 150,000





150,001 to 175,000






* EPA semi-annual minimum detectable leak rate may be 6.0 gallons per hour until October 13, 2021 for pipe segments greater than 100,000 gallons. After October 13, 2021, the minimum detectable leak rate cannot exceed 3.0 gallons per hour.


Waiting Time

None between delivery and testing.
None between dispensing and testing.

Test Period

Typically a minimum of 45 minutes after setup.
Piping must be isolated and blocked during test.

System Features

System may be permanently installed on pipeline to perform monitoring, or may be transported and set up to perform line tightness testing.
A single 45 minute test is required to simultaneously test as many sections as required consisting of typically two 15-minute monitoring periods at operating pressure, and one 15-minute monitoring period at a lower pressure level.
System measures pressure changes in the pipeline over time at two different set pressures in three different test periods, typically 15 minutes each and reports output quantity in gph. The procedure ensures thermally induced volume changes do not affect line pressure changes during the test. Typical test pressures vary from 60-160 psi. Other pressures may be used, but a pressure differential of 100 psi is usually maintained.
A test result is provided immediately after completion of each test for each test section. Pipeline segment being tested must be completely isolated.


System must be calibrated in accordance with manufacturer’s instructions. Calibration data is obtained prior to testing each specific pipeline segment.


Prior to conducting tests on a line, the HCNA Pipeline Leak Detection System V2.2 must be commissioned to confirm the existing line characteristics for each individual test section.
System may be used on large underground bulk pipelines such as airport hydrant fueling systems.
The third-party evaluations utilized a total of 84 tests at various facilities. 49 of these tests were conducted with various induced leak rates. 24 of the test were performed on pipeline volumes of less than 25,000 gallons.


Hansa Consult of North America, LLC (HCNA)

Evaluator:  Ken Wilcox Associates

200 International Drive, Bldg. 120

Tel:  (816) 443-2494

Portsmouth, NH 03801

Date of Evaluation: 12/15/05, 09/11/18

Tel: (603) 422-8833


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