If the space living in human beings is better than the physical body, the various pipes laid in the living space are better than the blood vessels and nerves. Transmit quality drinking water, the choice of pipe fittings is critical.
In view of the needs of environmentally friendly, most building water pipes are concealed engineering and pipe well project. If the pipe is used improper, according to the calculation, it will result in 10 to 20 times the value of the water pipe material itself is 10-20 times higher. An additional pipe is also a barometer for the development of the water industry development. 5 selection principles for water pipes: safety reliability, economy, hygiene, energy saving, sustainable development, which is also a major feature of green pipes, only can meet these principles, the truly tube.
The following gives us from several aspects of commonly used water supply pipe materials stainless steel pipe, copper tube, galvanized pipe, composite pipe (including steel, aluminum-plastic, copper-plastic and stainless steel composite pipe, etc.) and plastic tubes (including PE , PPR, PVC, etc.) compare.
1. Comparison of material strength
The most commonly used stainless steel in the water industry is 304 and 316 stainless steel, which can meet the vast majority of water treatment and lane conditions.
The tensile strength of the 304 stainless steel pipe is twice the steel pipe, which is 3 to 4 times the copper tube, and 8 to 10 times the plastic tube. The strength of the material determines whether the water pipe is strong and reliable. Safety and reliable is the most important requirement in building water. In the case of an external force impact, the possibility of water leakage of stainless steel pipe is extremely small, and the bronze tube and plastic tube leakage rate are relatively high, and the pipeline is easily damaged by construction or secondary decoration. The main reason for the domestic major urban residences on plastic water pipes is that one of the main reasons for leaking, leaking is that the plastic water pipe can not stand the external force impact.
High-rise water supply system work pressure is generally greater than 0.6MPa, which is high for pipe pressure. Plastic tubes are used in water supply system work pressure, which is less than this value. The two material expansion coefficients of the composite tube are large, such as the bonding or temperature change, is easily removed. The thin-walled copper pipe pressure is up to 5.9MPa, while the thin-walled stainless steel pipe can withstand high water supply pressure due to excellent mechanical properties, up to 10MPa, especially suitable for high-rise water supply.
In fact, many world-renowned high-rise buildings use stainless steel water supply. For example, Malaysia's Communication Tower is the fourth high communication tower in the world, with a 304 stainless steel pipe and a high-pressure Victaulic joint to water supply to a building of 421 meters. The Taipei Financial Center, which was built in 2004, 508 meters high, will be the world's highest building, and its water supply pipe includes a stainless steel pipe and VictAulic joint with a leading diameter of 318 meters.
2. Comparison of thermal expansion properties and insulation performance
The thermal expansion coefficient of the stainless steel tube is similar to the copper pipe, which is 1.5 times the ordinary steel pipe, which has the slow expansion of thermal expansion. Plastic tube expansion coefficient is too large, its fatal weakness is not suitable for heat pipe. Under the conditions of changes in ambient temperature, plastic tubes are prone to leakage, especially in hidden projects. The composite tube has problems with the inconsistency of the expansion coefficient of material, and the two material connectivity is prone to cracking, resulting in burst of water pipes.
The thermal conductivity of the stainless steel pipe is 1/25 of the copper tube, 1/4 of the ordinary steel pipe, especially suitable for hot water delivery, much better than the thermos of the copper tube.
3. Comparison of corrosion resistance
One of the most prominent advantages of stainless steel pipe is its excellent corrosion resistance, which is best in five pipes. Because stainless steel can passivate a passivation in the surface, form a tough and dense chromium-rich oxide protective film Cr2O3 on the surface, effectively preventing further occurrence of oxidation reactions. Other metal tubes, such as galvanized water pipes, copper tube passivation ability is small, which is a key reason for the corrosion resistance of galvanized tubes. Key reasons for stainless steel pipes.
Stainless steel does not occur even as carbon steel, there is no need to protect the coating during use; the stainless steel pipe is used, and the chemical composition of water is not limited, because stainless steel is in a variety of oxygen content, temperature, pH and hardness. Corrosion resistance; stainless steel pipe can withstand high flow rate, even if the flow rate is greater than 40 m / sec, still maintains extremely low corrosion rate, no more than 0.003 mm / year, especially suitable for high-rise water supply.
Stainless steel generally does not have local corrosion, 304 stainless steel can withstand the chloride content of 200 ppm, 316 stainless steel tolerance can reach 1000 ppm, which is based on exposure experiment data and has been confirmed by experience.
4. Comparison of health and environmental performance
The stainless steel water pipe is superior, eliminating the "red water, blue green water and hidden water" problem, no odor, no fouling, no harmful substance, maintain purity, pure water, harmless to human health. In foreign countries, laboratory tests in different countries have shown that the precipitation of stainless steel metal elements is 5% of the standard values specified by the WHO and European Drinking Act (the provisions of the world to refer to these two standards). Low. In fact, the stainless steel material itself is safe and non-toxic, cleaner, and has already been fully proved by stainless steel to successfully applied in various fields involving human health, becoming a well-known fact. Stainless steel not only has a long-term use of beverages, dairy, brewing, pharmaceutical industries, buttures, etc. Such as various brackets, artificial joints, and in vivo steel nails, etc., and become standard materials for the cleansing room of the semiconductor industrial clean room for cleanliness requirements. With the continuous improvement of water quality and the increasing strict control of pollutant release in water in water, the best pipes of high quality drinking water are not stainless steel.
Stainless steel pipes have the longest service life. From abroad, the use of stainless steel, the useful life of stainless steel pipe is up to 100 years, and at least 70 years, it is as long as the life of the building. The life of the composite tube is affected and limited by the life of the main material and thermal expansion, and the composite tube is complicated with two materials, and the possibility of the binding layer is large and affects life. The life of the plastic tube is difficult to determine in China. It is largely dependent on the quality of production technology and the quality of raw materials. The quality of the high-quality pipes can be up to 25 to 30 years, while the life expectancy of the fake tube may be only a few years. The aging problem of plastic tubes is relatively highlighted, sunshine, temperature, chemical, mechanical factors, time will cause its aging, aging plastics are prone to explosion in the impact of water pressure and water hammer, and the service life is greatly reduced. In addition, the hot melt connection method can make the joint or the material is deteriorated.
The stainless steel pipe is selected, and the initial investment is not high. It is generally believed that the stainless steel pipe is expensive. The actual situation is not the case, the birth of the thin-walled stainless steel pipe has created conditions for stainless steel pipes into the civilian market.