For cold water and the outer pipe made of polyethylene, for installation – PVC pipes, hot water and heating systems to the liner, perfect tubes made of polypropylene. And the price of their significantly lower zinc metal. Of course, as an enlightened man, you know something that the trouble with them, "your brother" (wink friendly plumbing) no less. Yes, and they last for 15 years, then still change. That's go, you poor guy, Lata old system.
This phrase is best to finish his speech and touched gently to offer the master to continue his work. Of course, you can elaborate on and shortcomings plastic pipes. But why scare the innocent? Plastic in the modern large-scale construction is still unavoidable. Yes, after all, is and has its own advantages. With these tubes you do not feel the familiar taste of water and metal rust. And the fact that any plastic has a high coefficient of thermal expansion (that is bursting from its very hot water) can be viewed as a positive thing. Suddenly, you'll want to get acquainted with neighbors, not only with the lower floors, but also from next door? In this case, when the end excuses for dating with matches and salt – safely install the plastic communication. But it will take up most, because if you suddenly the professional plumber will fall, he will be able to calculate this is the "fullness factor".
Then your plastic pipe may never appear in a neighbor's apartment. And the failure of the operation. You can also try to hopelessly well-established plastic water pipe to connect the latest washing machine (it is said that plastic pipes can not withstand temperatures above 90 C, and at discharge after boiling and is 100 C), but then again have to communicate with family downstairs neighbor.