+1 603 422 8833

Methodology

Our Methodology

Results you can trust

The HCNA Pressure-Step methodology is employed by both our permanent and “point-in-time” applications, and all LDS options offer the same performance accuracy and test time. Pipeline systems are tested and certified in accordance with the HCNA Pressure-Step, a US EPA recognized Third-Party certified method. The HCNA Pressure-Step methodology is capable of detecting a leak of 0.068 gallons per hour or 0.00078% of line volume, with a probability of detection (PD) > 95% and probability of false alarm (PFA) < 5% as per Ken Wilcox Associates, Inc. Third Party Certifications. Additionally, these methods were successfully evaluated at leak rates identified in 40 CFR 280.252 2015 EPA UST regulations.

The Pressure Step Theory

The HCNA Leak Detection System (LDS) utilizes the Pressure-Step methodology, a differential pressure method for assessing the tightness of isolated pipelines. The HCNA LDS measures pressure over time, converting pressure changes to volume changes using specific data from the tested pipeline. At the completion of the test, the pipeline’s tightness is evaluated based on the measured results and expressed in gallons per hour. The pressure-step methodology accounts for temperature change effects during the test.

How It Works

The Hansa Consult of North America, LLC Pressure Step Test Sequence consists of three cycles:

Cycle I:  After the pipeline section is completely isolated, the pressure of the test section is maintained at the operating pressure, ideally at or above 145psi. The measured pressure values are recorded by the HCNA equipment for a defined 2-minute period after a pre-set settle time is elapsed.

Cycle II:  The pressure in the fuel system is automatically lowered to a low-pressure level of ~45psi. After the system stabilizes during the pre-set settling time, HCNA equipment again records the pressure values.

Cycle III:  For evaluation purposes the same procedure as in Cycle I is executed.

Evaluation

The determination of a leak is most influenced by temperature and pressure changes during testing. The Pressure Step method is based on the physical fact that given a defined leak size; the leak rate would be proportionately larger at higher pressure than at lower pressure.  Because the leak rate is directly related to a change in pressure, it can be determined from the pressure gradients during the test, whether the system is or is not tight. The HCNA Pressure-Step program compares the pressure curves of the different pressure levels (cycles) and determines the resulting leak rate results.

Using the Pressure Step methodology, HCNA is able to determine the leak rate based on the specific properties of the material and geometry of the piping system being tested. The evaluated test results are recorded in a statistical database.  The reliability of HCNA’s method can be verified at any time through controlled, manually created leak simulation tests.

HCNA Hydrant Tight® Automated LDS

What sets us apart

The HCNA Hydrant Tight® leak detection system provides a fixed, automated factory assembled and tested leak detection system for tightness testing DOD hydrant systems. The system consists primarily of an HCNA Hydrant Tight® Panel to be located in the Pumphouse Control Room. The Hydrant Tight® Panel contains an operator interface HIU and PLC which will interface with the existing Hydrant System PLC to establish the system dual pressure conditions required during the tightness testing program. The Hydrant Tight® Panel also connects to an installed pressure transmitter which provides the pressure data during leak detection testing. The identified hydrant loop piping segments are tested as one section during a single 10–45-minute test period. The HCNA Hydrant Tight® leak detection system interfaces with the installed Hydrant Fuel System Control and Annunciation System (HFSCAS). The HFSCAS controls the valves to enclose the hydrant loop test sections before the leak detection test begins and reopens these valves once the test is complete. To establish dual pressures required during testing, the designated pumphouse hydrant valves along with the installed leak detection hydrant loop bypass pressurization/depressurization valve are controlled by the Hydrant System PLC and sequenced by command from the HCNA Hydrant Tight® Leak Detection System PLC. The operator initiates the test by pressing a button on the HCNA Hydrant Tight® HIU panel. No operator action or input will be required once the test is initiated. Once the test is complete, the test results are automatically generated by the HCNA Hydrant Tight® software package.        

Get in touch with us

Contact Us

Hansa Consult North America, LLC
200 International Drive, Suite 120, Portsmouth, NH 03801
+1 603 422 8833

© 2025 Hansa Consult of North America, LLC — All Rights Reserved.