Testing of plastic pressure NPVC pipelines

Pressure NPVC pipelines, including fittings, must be tested on strength and impermeability via hydraulic method in accordance with the requirements of section 11 of the “СН 478-80” standard.

NPVC pipelines must be tested at an ambient temperature above 0°C. Before testing pressure plastic pipeline systems, temporary and permanent support rests should be mounted near the ends curves of the pipeline. The joints must be visible and accessible.

Preliminary hydraulic testing of pressure plastic pipelines for water-supply systems

The preliminary hydraulic test of pressure plastic pipelines for water-supply systems is carried out for sections not more than 0,5 km long. The procedure is as follows:

• the pipeline is filled with water and kept without pressure for 2 hours;
• test pressure is fed to the pipeline and maintained for 30 minutes, then the pressure is reduced to nominal operating value and the pipeline is inspected thoroughly.

The pipeline is kept under operating pressure not less than 30 minutes. If there were no visible leakage of water under the test pressure, it is considered that the pipeline had passed the preliminary hydraulic test.

Hydraulic impermeability testing of pipelines for water supply systems

The final hydraulic impermeability test of pipelines for water supply systems is started not sooner than 48 hours after backfilling the trench and not sooner than 2 hours after filling the pipeline with water. The procedures are as follows:

• The pipeline is fed up with nominal operating pressure respective to the pipe type. The pressure is maintained for 2 hours.
• If the pressure decreases by 0,02 MPa, water must be pumped up. The pressure is increased to the test level within not more than 10 minutes and maintained for 2 hours.

If the pressure falls by 0,02 MPa during this period, water must be pumped up. The leakage of water can be revealed by measuring the amount of water which was added to maintain the test pressure.