How is the 50-year service life of plastic pipes derived?

We often say that the service life of plastic pipes is 50 years. Everyone knows that the application and development of plastic pipes has only been developed for more than 20 years. Where does 50 years come from?

    The 50-year life span of plastic pressure pipes is derived from the properties of polymer materials and corresponding experiments.

High-resolution materials are particularly sensitive to temperature response. The experiment adopted the principle of time-temperature equivalence, that is, increasing the temperature and increasing the extension time are equivalent.

The results of the loop stress versus time curve made using high temperature and short time are extrapolated to low temperature and long life.

    The evaluation standard of pipe service life is ISO9080 'Determination of Long-term Hydrostatic Strength of Thermoplastic Pipe by Extrapolation Method',

Corresponding to the national standard GB/T18252-2000 'Plastic piping system push method to determine the long-term hydrostatic strength of thermoplastic pipes'.

   The picture shows the results of the blasting test with PE100 pipe passing time intervals ranging from 1 hour to 10,000 hours (about 14 months).

Perform regression analysis on the test results to predict the long-term strength of the pipe at 20°C in 50 years.

   Pay attention to the following items during transportation, storage, installation and use of pipes, so as not to affect the service life of the product.

①Scratch the pipe to reduce the actual effective wall thickness of the pipe, which is equivalent to lowering the pressure rating of the pipe.

②Long-term sunlight causes the pipe to produce a certain degree of photo-oxygen aging. The test data is as follows:

After 60 days of unpackaged exposure, the probability of brittle failure at 95℃, ring stress of 4.4Mpa and 1000 hours of test conditions is high.

After 90 days exposure to 95℃, the ring stress is 4.8Mpa, the probability of brittle failure in 16 hours is very high, so it must be stored properly and not exposed to strong light for a long time.

③The installation gap is too large, the pipeline is too long, the temperature is uneven or not hot, and the temperature of the system is artificially increased. The higher the temperature, the faster the fatigue and the shorter the service life.

Therefore, it is not possible to cut corners and reduce costs to save installation costs.

④If you do not pay attention to the installation, the pipe will bend and form a dead angle, which will affect the use effect and service life.

⑤The ground is not leveled during the construction period, the height of the pipes is inconsistent, forced extrusion, and the external pressure is different.

⑥The mark is not obvious after installation, and the pipe is damaged by any drilling.

⑦Pay attention to the entry of impurities when the pipe is drilled or passes under the door frame.

⑧ The gas must be drained during pressure test to prevent the formation of air hammer or water hammer. After the water pressure is tested, if it is not used in time, the water must be drained to prevent the water from being frozen in winter.

⑨Clean the filter regularly.

   In the process of transportation, installation and use, there are still many situations that affect product quality. In short, high-quality materials, advanced and sophisticated equipment molds and testing instruments,

Strict process management and quality control, coupled with good product maintenance, standardized installation, and standardized use, can ensure that the service life of the pipe reaches more than 50 years.