PE pipe fittings can be used in water supply pipes, and the PE water supply pipe system should undergo pressure testing before being put into operation. The pressure test includes two parts: strength test and water tightness test. It is generally recommended to use water as the test medium during testing. Here are two experimental methods:
Strength test:
After eliminating the air inside the PE pipe to be tested, increase the pressure to the required value at a stable rate, and place the pressure gauge at the lowest point of the PE pipe as much as possible.
Pressure testing can be conducted before or after pipeline backfilling. PE pipes should be covered with soil at certain intervals, especially for serpentine PE pipes. During pressure testing, the PE pipes should be fixed in place. The flange connection should be exposed for easy inspection of leaks.
The test pressure for pressure testing should not exceed 1.5 times the pressure rating of the pipe or the lowest pressure rating of the fittings in the system. At the beginning, the pressure should be raised to the specified test pressure value and held for sufficient time to ensure that the pipe fully expands. This process takes 2-3 hours. After the system stabilizes, the pressure should be raised to 1.5 times the working pressure, stabilized for 1 hour, carefully observed on the pressure gauge, and patrolled along the line. If there is no visible leakage or significant pressure drop during the testing process, the PE pipe passes the pressure test.
During the pressure testing process, the continuous expansion of the pipe will cause a pressure drop, resulting in a certain amount of pressure and force drop. This is normal and cannot prove that the PE pipe system is definitely leaking or damaged.
Water tightness test:
The test pressure for the water tightness test of PE pipe fittings shall not exceed the pressure rating of the pipe or 1.5 times the lowest pressure rating of the fittings in the system. When the pressure of the PE pipe reaches the test pressure, it should be maintained for a certain period of time to ensure that the temperature of the test medium inside the PE pipe is consistent with the ambient temperature of the PE pipe. After the temperature and pressure are stable, the timer should be started. In general, the water tightness test should be stabilized for 24 hours. After the test, if there is no obvious leakage or pressure drop, it is considered to have passed the test.
Although its application started relatively late in China, PE pipes and fittings have become ideal pipes for water supply engineering due to their low comprehensive cost, convenient construction, good hydraulic conditions, non toxicity, corrosion resistance, low temperature resistance, and resistance to mechanical vibration, with great development space.