PVC pipe is toxic? What is the price of pvc pipe?

PVC pipe is toxic? What is the price of pvc pipe?

PVC pipe (UPVC pipe) hard PVC pipe is made of polyvinyl chloride resin and stabilizer, lubricant and so on. It is extruded by hot pressing method. It is the first plastic pipe that has been developed and applied. UPVC pipe has strong corrosion resistance, easy adhesion, low price and hard texture. However, due to the oozing of UPVC monomer and additives, it is only suitable for water supply systems with a delivery temperature not exceeding 45 °C. Plastic pipes are used to transport drinking water, wastewater, chemicals, heating fluids and coolants, food, ultrapure liquids, slurries, gases, compressed air and vacuum systems.

The staff of the National Plastic Products Quality Supervision and Inspection Center said that users who use PVC water pipes in China are still more common. PVC water pipes and PVC cling film have nothing to do with them. They are qualified for the inspection of PVC water pipes. There is no toxic phenomenon of water pipes. Residents can use PVC pipes with confidence. However, some experts said that PVC pipes are not necessarily all toxic. The qualified PVC itself is safe and non-toxic, and has the advantages of energy saving, impact strength, chemical corrosion resistance and flame retardancy, which can be reduced to minus 30 degrees Celsius. It is recommended for use by the Ministry of Construction in the temperature environment of 70 degrees Celsius.

PVC will be added to the stabilizer during production, but the stabilizer is non-toxic and toxic. Only when a toxic stabilizer such as lead salt is added will it cause hidden dangers. However, PVC products are mixed, and some small enterprises use lead salts as stabilizers, and it is difficult to meet relevant health standards. When consumers choose PVC materials, it is best to purchase them in the building materials market with formal and credible quality assurance, and require suppliers to issue inspection reports. Consumers should pay attention to check the relevant documents and signs, and obtain the products that are related to the Hygiene License for Drinking Water Hygiene and Safety Products.

What material is good for the pipe?

When you arrive at the building materials city, you will find that the water pipes are dazzling, and there are many kinds of PP-R pipes, PVC-U pipes, plastic-lined steel pipes, stainless steel pipes and copper pipes.

The water pipe should be stable and reliable, no water leakage, no bursting

The term "safety durability" refers to the occurrence of life-threatening and family safety incidents such as water leakage and bursting during the service life of the water pipe, which can guarantee long-term use.

This requires the water pipe to be corrosion resistant, high temperature resistant, frost resistant and has good mechanical properties. Contrast found that plastic pipe can not withstand high temperature, it is easy to deform and cause leakage under the condition of large temperature difference, and its resistance to pressure is small and easy to be brittle. These are destined to be unsuitable for long-term heating, and should not be used in cold north. Not suitable for high-rise buildings.

Composite pipe combines the advantages of metal and plastic, but it is precisely because of the different expansion coefficients of plastic and metal that long-term use will lead to stratification of the pipe and cause harm.

For copper tubes, we all know that copper has a low order in chemical activity sequencing, stable performance and strong corrosion resistance. Copper is a material with certain strength and excellent plasticity and toughness in metal. It has excellent low temperature performance. Therefore, copper water pipes can resist heat and fire, not aging, and have certain anti-frost properties. The copper pipes installed in Peking Union Medical College Hospital in the 1920s have experienced vicissitudes for more than 80 years, and still have good performance, indicating that copper pipes can be durable and have long-term safety and reliability equivalent to the life of buildings. In addition, the copper tube is durable and has a low coefficient of thermal expansion, making it ideal for embedding in concrete walls without fear of wall cracking. However, copper pipes are more expensive.

Copper tube can inhibit the growth of bacteria

The main components of plastic pipes are some high-molecular polymers, which have certain toxicity and are relatively easy to penetrate. Especially if used in direct drinking water supply systems, they are seriously harmful to the human body. Another example is the water pipe that has not been used for a long time. When you suddenly open it, you find that the water is “yellow”. In the past, the galvanized iron pipe in the house is very prone to such a thing. Such “yellow” water is also harmful to the human body. Copper water pipes can inhibit the growth of bacteria. E. coli can no longer continue to reproduce in copper pipes. More than 99% of E. coli and pneumonia bacteria disappeared after entering the copper pipeline for 5 hours, keeping the drinking water clean and hygienic.

PP-R and copper tube can be buried in the wall

We all know that plastic pipes are extremely convenient to install, but most of the components connected to them are metal parts. Due to the large difference in mechanical properties between plastic and metal, it is easy to cause burst or water leakage. Therefore, it is generally not allowed to be buried in the wall during construction. Can only be laid outside. The PP-R and copper pipes and their accessories are available in various varieties and specifications, and can be selected from 6mm-250mm. PP-R pipe can be seamlessly welded, and the manufacturer can also be buried in the wall when installing. It has the advantages of cheaper price and convenient construction. The cutting, bending, processing and welding of copper tubes are also simple, and the connection forms are various, including brazing, ferrules, crimping, plugging, flanges, grooves, etc., which can fully satisfy various occasions and situations. need.

The difference between PE water pipe and PPR water pipe

In drinking water, PE is generally used as a cold water pipe; PPR (special hot water material) can be used as a hot water pipe; and PPR (cold water material) can be used as a cold water pipe;

If it is to do hot water pipe, of course, PPR is good;

(If it is a drinking water pipe in the home, then there is no difference, basically all use PPR than PE)

If you are doing a cold water pipe, you can refer to the following differences:

I. Comparison of temperature resistance between PPR water pipe and PE water pipe

Under normal use, the PE water pipeline has a maximum stable temperature of 70 ° C and a minimum temperature of -30 ° C. That is to say, in such a temperature range, long-term use of PE water pipes is safe and reliable.

Under normal use, the PPR water pipeline has a maximum stable temperature of 70 ° C and a minimum temperature of -10 ° C. It also shows that in such a temperature range, long - term use of PPR water pipes is safe and reliable. It is concluded that the PE water pipe has the same high temperature resistance as the PPR water pipe. However, PE pipes are superior to PPR pipes in low temperature performance.

Second, the difference between PE water pipe and PPR water pipe in terms of hygiene

PE pipe is the main chemical molecular component of polyethylene. Readers of organic chemistry know that the composition of this product is two carbon atoms combined with five hydrogen atoms, one of which is combined with a carbon atom by a double bond, and then ethylene The single molecule is polymerized in a certain way, and such a product is a polyethylene product. So what is the PPR water pipe? The main component of the PPR water pipe is propylene, that is, three carbon atoms are combined with seven hydrogen atoms, and one of the hydrogen atoms and the carbon atoms is bonded by a double bond, and then the polymerized product is a polypropylene product. Such products are almost the same in terms of health and safety. What is important is whether the raw materials used by the company are not suitable, rather than the difference between the two products. There is no basis for propagating PE pipes in newspapers that are more hygienic than PPR pipes. All qualified PE water pipes and PPR water pipe products must be sanitized (except those for counterfeit and shoddy products). It is said that PE water pipes are more hygienic and safer than PPR water pipes, and they are also deceiving to consumers.

Third, the modulus of elasticity

The elastic modulus of PPR water pipe is 850MPa. The PE water pipe belongs to medium density polyethylene. The elastic modulus is only about 550MPa. It has good flexibility and insufficient rigidity. It is used in the construction water supply field. The straightness of the pipe is not good, it is easy to bend and easy to deform. Not beautiful.

Thermal conductivity: PPR water pipe is 0.24, PE water pipe is 0.42, nearly doubled. If it is used in floor heating, this is its strength. The good heat dissipation indicates that the heat radiation effect is better, but it is used in the hot water pipe. Disadvantages, good heat dissipation, large heat loss, higher surface temperature of the pipe, easy to hot.