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How to judge the quality of a PP-R pipe

Time:2014-09-11 12:08


The following are several methods to properly identify the quality of PP-R pipes:

1. Look at its exterior.

Good PP-R pipes do not have a mixed color. It has a soft and uniformed color and luster.

2. Feel.

Quality PP-R pipes are made without any additives and completely of pure PP-R materials. Itssurface is bright and clean, and feels soft. Fake PP-R pipes feel smooth, and any rough particles may indicate impurities being mixed in.

3. Smell.

PP-R pipe main material is polypropylene, a good pipe does not smell, smell the difference there is likely to be blending the polyethylene, polypropylene instead.

4. Bend.

The main material in PP-R pipes is odorless polypropylene. Therefore, good pipes have no smell. Poor quality pipes have a peculiar smell, most likely due to the material not being made of pure polypropylene.

5. Measure its thickness.

Also you can use vernier caliper, pipe wall thickness and uniform standards are generally good tubes are produced strictly according to GB, but this method requires the national standard PP-R pipe has a certain understanding.

6. Listen. When falling to the ground, PP-R pipes will make a clunking sound, whilefake pipes will sound clear and melodious.

7. Smash resistance.

PP-R pipes have a good rebound elasticity. Pipes that can easily be smashed into pieces are naturally not very good. However, at temperatures below 10 degrees, even good PP-R pipes can be smashed. However, high hardness does not represent good rebound elasticity. Some manufacturers mix in many impurities such as calcium carbonate, etc. to increase hardness, which while it cannot be easily smashed, it will easily crack over time.

8. Burn and smell.

When being burned, those mixed with recycled plastics and other impurities will produce black smoke with a sharp smell. But for those pipes made of good materials, it will not only produce odorless black smoke, but the melted liquid resulting from the burning will still be clean.

9. Welding.

The normal welding temperature of PP-R pipes ranges from 260 to 290℃, in which the welding quality can be ensured. Within normal welding parameters, the pipes can be placed into the die head easily. Those with accumulated beads almost transparent are not authentic PP-R pipes, and if the accumulated beads cool down rapidly and become hard (normally within 10 seconds), they are also not authentic. One of the features of PP-R is that it has a good insulative effect, thus it naturally cools down slowly.

Additionally, pipes should be checked for deformities on the inside parameter and for cobwebbing, which is hard to find on good PP-R pipes.

10. Inspect.

Test instruments should be used to distinguish good PP-R pipes from fake or inferior ones. In national standards, several items of testing requirement data are specified. For instance, Pipe Aging-Resistance Test (8760 hours without any failure under 1.9MPa of cycle stress at a temperature of 110℃), Piping System Stability Test (5000 hot and cold cycles), the Impulse Withstand Test, etc. Therefore, users may require the manufacturer or dealer to provide the test report. Additionally, the national standards also specify a melt index for piping and pipe fitting materials. The standards state that the change value between the melt indexes before and after being processed should not exceed 30%, and in this industry, there is a requirement that the melt index of materials not exceed 0.5g/10min.



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