For everyone concerned about the quality of the PPR tube, many users actually have some misunderstanding. For example, if PPR pipes can be smashed, it means they are of poor quality. No, it doesn’t prove the quality of the pipes. This is due to the low temperature brittleness of PPR water pipe itself.
The raw material of PPR tube is random copolymer polypropylene, which is called type III polypropylene. It is obtained by random copolymerization of propylene monomer and a small amount of ethylene monomer under heating, pressure and catalyst. Ethylene monomers are randomly distributed in the long chain of propylene, in which ethylene monomers are generally controlled between 3 and 5. The content of ethylene and the polymerization mode of ethylene and propylene determine the characteristics of cold brittleness.
In the case of low temperature, especially in the winter construction process, the flexibility of the pipe at low temperature is reduced, the rigidity is enhanced, showing brittleness. Under the impact of external force or excessive accidental load, the pipe may crack in a straight line. Bring inconvenience to the construction. Therefore, the relevant national norms have made clear requirements for this problem.
In winter construction, attention should be paid to the characteristics of low temperature brittleness of PPR pipeline for building water supply, and the corresponding construction scheme should be formulated. GB/T50349-2005 has detailed regulations on this. When the ambient temperature is low, the toughness of PPR pipe decreases, showing brittleness. When the pipe is affected by external force or heavy pressure, there will be linear cracking phenomenon, and the cracking starts from the inner pipe and extends to the outer pipe. When the pipe is cracked by the force of a point, the crack will grow rapidly along the axis of the pipe within a moment, which is called rapid crack growth. In addition, in winter, the pipe will be damaged by external force during transportation, construction site and installation, and brittle and ductile pipe burst will occur in the process of use.
On the contrary, some fake PPR tubes with other raw materials are not easy to break. PPR tubes that can deliver both hot and cold water for 50 years can be cracked, especially at low temperatures, and this is the low temperature brittleness of PPR.
If the PPR pipe cannot be cracked, it is basically concluded that it is not PPR material. The advantages of PPR tubes are mainly reflected in the high creep resistance. The good tube of pure PPR material has low temperature brittleness, which is particularly obvious in the environment below 5℃, so the good tube can be cracked, and the ones that can not be cracked are often not PPR tubes. This is different from some advertising, and users should be careful when making purchases.
