The selection and installation of water pipes in "concealed engineering" has become a problem that cannot be ignored in decoration. In order to make the living room beautiful, people usually use buried wall construction when decorating water pipes. Once the water pipe leaks and bursts, it will bring irreparable consequences.
In the past, the pipes used for water supply were mainly cast iron pipes. Sand cast iron pipes are mainly used outdoors, and galvanized cast iron pipes are used indoors, which are divided into cold (electric) galvanized and hot-dip galvanized. Galvanized pipes are used as water pipes. After several years of use, a large number of rust scales have been produced in the pipeline. The yellow water not only pollutes the sanitary ware, but also is mixed with bacteria that breed on the unsmooth inner wall. Due to corrosion, the content of heavy metals in water is too high, which seriously harms human health. The state stipulates that from June 1 2000 onwards, sand casting process pipe fittings and cold galvanized cast iron pipes will be eliminated, the use of hot galvanized cast iron pipes will be gradually restricted, and aluminum-plastic composite pipes and new plastic pipes will be popularized. Therefore, there are three main types of pipelines currently in use. The first category is metal pipes, such as hot-dip cast iron pipes lined with plastic, copper pipes and stainless steel pipes. The second category is plastic-coated metal pipes, such as plastic-coated steel pipes and aluminum-plastic composite pipes. The third category is plastic pipes, such as PP-R (cross-linked polypropylene high-density network engineering plastic).
The state also stipulates that all kinds of pipes and fittings involved in drinking water pipelines must be approved by the health department before they can be sold.
(1) aluminum-plastic composite pipe
Aluminum-plastic composite pipe is a popular pipe in the market at present, which is light and durable, convenient to construct and flexible and more suitable for home decoration. The main disadvantage is that when used as a hot water pipe, long-term thermal expansion and cold contraction may cause dislocation of sleeve-type connection and leakage. At present, there are many kinds of aluminum-plastic composite pipes sold in the market, with great differences in quality and price. How to choose aluminum-plastic composite pipe has become a headache for consumers.
① Check the product appearance.
High-quality aluminum composite pipe generally has a smooth outer wall, and the trademark, specification, applicable temperature and meter number are clearly marked on the pipe wall. The manufacturer also prints the production number on the pipe wall to monitor the product quality at any time. The product is well packaged, and all kinds of signs on the package are equally clear. The name, address and telephone number of the manufacturer are printed in a prominent position. Fake and shoddy products generally have rough outer walls, unclear or incomplete marks, simple packaging and unknown address or telephone number.
② Aluminum layer can't be ignored.
A good aluminum-plastic composite pipe is welded at the lap joint of aluminum layer, and the aluminum layer and plastic layer are closely combined without delamination. However, the aluminum layers of some fake and inferior products are not welded, and some aluminum layers and plastic layers are often layered and not tight.
(2)PP-R tube
As a new type of water pipe material, PP-R pipe has unique advantages. It is non-toxic, light, pressure-resistant and corrosion-resistant. Special hot-melt connection will not corrode and rust, and PP-R pipe will not scale, so it is a kind of material being popularized. Because of its simple manufacturing process, a large number of counterfeit products have appeared in the market at present. In order to help the owner identify the authenticity of PP-R pipes and fittings from the appearance and feel, you can refer to the following identification methods:
① Product name: The product name of real PP-R should be "polypropylene pipe for cold and hot water" or "PP-R pipe for cold and hot water", and the irregular names of superfine particle modified polypropylene pipe (PP-R) or PP-R cold water pipe, PP-R hot water pipe and PP-E pipe are all pseudo-PP-R pipes.
② The density of pseudo-PP-R is slightly higher than that of real PP-R. ..
③ True PP-R tubes are white matt or other matt colors, while pseudo PP-R tubes are bright or bright colors.
④ True PP-R tube is completely opaque, while pseudo PP-R tube is slightly translucent or translucent.
⑤ The real PP-R tube feels soft, while the fake PP-R tube feels smooth.
⑥ The landing sound of real PP-R pipe is dull, and the landing sound of fake PP-R pipe is crisp.
It should be pointed out that the service life of pseudo-PP-R tube is only 15 years, while the service life of real PP-R tube is 50 years (3) copper tube.
Copper tube has the advantages of corrosion resistance and sterilization, and is the first-class product in water pipes. There are two ways to connect copper pipes: clamping and welding. Like aluminum-plastic pipes, ferrules have the problem of aging and water leakage for a long time, so users who install copper pipes mostly use welding, that is, welding the joints together with oxygen, so that it will never leak like PP-R water pipes. One disadvantage of copper tube is its fast heat conduction, so the hot water pipes produced by well-known copper tube manufacturers are all wrapped with plastic and foaming agent to prevent heat dissipation. Another disadvantage of copper tube is its high price. There are few residential water supply systems made of copper pipes, and I am afraid they will only be seen in export apartments and high-end villas. If you plan to change the water pipe and think the copper pipe is good, it is recommended to use welded joints.
(4) Stainless steel pipe
It is a very expensive water pipe, which is difficult to construct and rarely used, and its performance is similar to that of copper pipe.