Many users actually have some misunderstandings about the quality of PPR tubes that everyone cares about. For example, PPR water pipes can be smashed, indicating that their quality is not good. In fact, no, this does not prove the quality of the water pipe. This is due to the low temperature brittleness of the PPR water pipe itself.
The raw material of PPR pipe is random copolymerized polypropylene, which is what we call type III polypropylene. It is obtained by random copolymerization of propylene monomer and a small amount of ethylene monomer under the action of heat, pressure and catalyst. Ethylene monomers are randomly distributed into the long chain of propylene, where ethylene monomers are generally controlled between 3-5. The ethylene content and the polymerization method of ethylene and propylene determine its cold brittleness.
In the case of low temperature, especially in the construction process in winter, the flexibility of the pipe is reduced at low temperature, and the rigidity is enhanced, showing brittleness. Under the impact of external force or excessive accidental load, the pipe may crack in a straight line. Inconvenience to construction. For this reason, the relevant national regulations have made clear requirements on this issue.
During construction in winter, attention should be paid to the characteristics of low temperature brittleness of building water supply PPR pipes, and corresponding construction plans should be formulated. GB/T50349-2005 has detailed regulations on this. When the ambient temperature is low, the toughness of the PPR pipe decreases, showing brittleness. When the pipe is impacted by external force or heavy pressure, there will be a linear cracking phenomenon, and the cracking situation starts from the inner pipe and extends to the outer pipe. After the pipe is cracked by the force of a point, the crack will grow rapidly along the axis of the pipe in an instant. This feature is called rapid crack growth. In addition, the pipes are injured by external forces during transportation, construction sites and installation in winter, and brittle and ductile pipes will burst during use.
On the contrary, some fake and inferior PPR tubes with other raw materials are added, which are not easy to break. PPR pipes that can transport both high temperature hot water and cold water and can be used for long-term durability according to standards can be cracked, especially when the temperature is low. This is the low temperature brittleness of PPR.
If the PPR water pipe cannot be broken, it can basically be concluded that it is not a PPR material. The advantages of PPR pipes are mainly reflected in higher creep resistance. The good tube of pure PPR material has low temperature brittleness, which is especially obvious in the environment below 5 °C, so the good tube can be cracked, but the ones that cannot be cracked are often not PPR tubes. This is different from some propaganda, and users should be careful when purchasing.
