PERFORMING PRESSURE TESTS IN PEXGOL WATER SUPPLY LINES AND DEWATERING

Test purpose:

Final check to make sure there are no leakages in the fittings.

Test procedure:

  • Make sure the underground pipes are already covered, leaving only the fittings uncovered It is recommended to fill up the pipeline with water at the maximum working pressure on the day before the test.
  • On the day of the test, inspect the pipeline visually, especially around the fittings.
  • Attention! Temporarily cover metal fittings (flanged couplings, branch-off saddles) to prevent excessive heat buildup due to exposure to sunlight.
  • For installation above the ground, test pressures in the table. Take into consideration that the pipe might be heated due to exposure to sunlight.
  • Take into consideration changes in the pipeline topography (which could create higher local pressure due to a water column); reduce the test pressure accordingly.

Pressure testing:

  • Bring the pressure to the level of the test pressure (see table 77.1) and then close the feeding line.
  • As the pipe is flexible and tends to expand its diameter under pressure, the line pressure is expected to decrease.
  • Increase the line pressure again, up to the test pressure.
  • With each cycle of pressure reduction and increase, the pressure is expected to decrease less.

After 3-4 cycles, open the valve and close it immediately, rapidly lowering the pressure to approx. 75% of the test pressure by letting water out of the line. After closing the valve, the pressure is expected to increase as a result of the tendency of the pipe to decrease its volume. If the pressure decreases instead of increasing, investigate the reason for pressure loss, for example, leakages at the fittings.

Pressure test:

Pipe class Test pressure – bar
Underground inst. Above ground inst.
Fluid Temp. Ambient Temp.
20º 30º 40º 20º 30º 40º
6 7.0 6.0 5.5 5.5 5.0 4.0
8 9.0 7.5 7.0 7.0 6.0 5.5
10 12.0 10.0 9.0 9.0 8.0 7.0
12 14.0 12.5 11.0 11.0 10.0 8.5
15 18.0 15.5 14.0 14.0 12.5 11.0
19 22.0 20.0 17.5 17.5 15.5 14.0
24 29.0 25.0 22.0 22.0 20.0 17.0
30 35.0 31.5 28.0 28.0 25.0 22.0

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