High Density Polyethylene (HDPE) Testing
A brief overview of the ASTM F 2164-02 Procedure

Ewbank Geo Testing is pleased to add another testing service for ground heat exchangers (ghex). Your Ewbank thermal conductivity data acquisition unit is used to collect the data for the HDPE hydrostatic pressure test. The three pin connector of the data acquisition unit for the flow meter is used to connect a pressure transducer to the data acquisition unit. Ambient temperature is obtained by using one of the temperature connectors used for the in-situ thermal conductivity testing. A software program is executed that records the time, temperature and pressures for the test.

The purpose of the test is to confirm that the ghex is fused properly and does not have leaks. The test process is under the ASTM guidelines and is the industry standard. Each test provider should have a copy of the ASTM designation F 2164-02 Standard Practice for Field Leak Testing of Polyethylene (PE) Pressure Piping Systems Using Hydrostatic Pressure. Ewbank is securing a written copy of this standard for each test provider from ASTM. This document is not readily available and must be purchased by each user.

The Test Records consist:
1. The test liquid.
2. Backflow prevention devices, if used.
3. The weather conditions and ambient temperature at site during test.
4. The test pressure.
5. The type of test gages in the test section.
6. The placement of test gages in the test section, with elevations.
7. Test gage calibration records.
8. The test pressures recorded during the test.
9. Any adjustments made to test pressure for the elevated temperature.
10. The test duration.
11. A description of test section length, elevations, and site location; usually provided by the Owner/Engineer of Record.
12. A description of the test section components.
13. Description of any leaks or failures and the corrective actions.
14. The date and time of the test.
15. The test operator.
16. The duration of the test should not exceed eight (8) hours if the maximum test pressure is between the system design pressure and 1.5 times the design pressure. When the maximum test pressure is at or less than the system design pressure then seventy-two hours is suggested for the duration.
17. The authority having jurisdiction to determine the maximum pressure.


The basics of the test are (for testing between design pressure and 1.5 times design pressure):

1) Flush debris and then purge all air from the piping to be tested.
2) Close off by valves or other method the piping to be tested.
3) Slowly, add water with a positive displacement pump to raise the system pressure to the maximum determined by the authority having jurisdiction.
a. The maximum pressure is 1.5 times the design working pressure less the elevation hydrostatic head. An example: if the static water level in a vertical ghex is one hundred feet below the surface; one must reduce the testing pressures to not over pressure the vertical piping. Maximum pressure for SDR-11 PE testing is 1.5 times the design (1.5 x 160= 240 psig) less 100 feet of dry borehole or (100 x .4335= 43.35, psi reduction) therefore, it is 240 minus 43.35 or 196.65 psig maximum testing pressure.
b. Typical design (maximum operating) pressures: for SDR-9 is 200 psi, for SDR-11 is 160 psi, and SDR-13.5 is 128 psi; and is to be reduced for higher temperatures. Typically, the design temperature for HDPE is 73.4 °F. Usually it is the horizontal and above ground sections of the ghex that are above this temperature. Consult the HDPE manufacturer for the temperature reductions for pressure ratings.
4) Allow the test section of piping and test liquid to equalize in temperature.
5) Add make up water as necessary for four (4) hours to maintain test pressure.
6) Reduce pressure by ten (10 psi), by letting water out and then closing the system.
7) Monitor for one (1) hour, do not increase pressure or add water.
8) Pass/Fail Criteria: if no leakage is visually observed and the pressure remains steady (within 5% of the pressure at item # 6) then a passing test is indicated.

Garen N. Ewbank,
Ewbank Geo Testing, LLC
121 E. Broadway, Suite 401
Fairview, OK 73737