Comparison of the advantages and disadvantages of various new chemical pipes in engineering applications

With the rapid development of our country’s economy and the continuous improvement of people’s living standards, people’s requirements for quality of life are also increasing day by day. With the new concept of modern life – letting green enter the home, a number of new green environmentally friendly pipes closely related to people’s daily life have emerged, such as aluminum-plastic pipes, PP-R pipes, PP-B pipes, and PE-X pipes. , PE pipe, etc. In order to speed up the promotion of these new pipe materials, the former State Economic and Trade Commission, the General Administration of Technical Supervision, Inspection and Quarantine, and the former State Building Materials Administration jointly issued the “Notice on Eliminating Outdated Products in Residential Construction” as early as 1999, which clearly stated: Since 2000 Starting from June 1, 2020, it is prohibited to use cold-dip galvanized steel pipes as indoor domestic water supply pipes in new urban residences. Hot-dip galvanized steel pipes will be gradually used for a limited time according to local actual conditions, and aluminum-plastic pipes and three-type random copolymer pipes will be promoted. Poly (PP-R) pipes, cross-linked polyethylene (PE-X) pipes and other new chemical pipes. In order to cooperate with the national promotion and application of these new chemical pipes, more than 30 provinces and cities across the country have issued local policy documents, and also through various forms such as technical exchange meetings and exhibitions. Let relevant professionals and ordinary people know and understand the high-quality characteristics of these new chemical pipes: green and environmentally friendly, acid and alkali resistance, corrosion resistance, durability, light weight and low price, economical and beautiful, easy construction, hygienic and energy-saving, etc.
It is precisely because of the high-quality characteristics of these chemical pipes that people can change the way they use steel pipes for heating in their lives, and the popular low-temperature floor radiant heating, buried pipe laying and other forms have quietly entered thousands of households, bringing Provide people with endless comfort and enjoyment. It can be said that the promotion of new chemical pipes has brought a new history to the pipeline industry. Moreover, in recent years, the demand for new chemical pipes in engineering has increased at an alarming rate every year, showing people the broad development prospects of new chemical pipes.
Comparison of performance advantages and disadvantages: 1. Advantages of three-type random copolymer (PP-R) pipe: (1) Recyclable, non-toxic, tasteless, green and environmentally friendly. (2) Hot melt connection, easy construction, no leakage, saving labor and time. (3) Pipes can be installed exposed or concealed. (4) The performance and price are relatively high. (5) The inner wall of the pipeline is smooth, the resistance is small, the circulation capacity is enhanced, and energy saving and consumption reduction are achieved.
(6) Widely used in domestic hot and cold water pipes, floor heating, heating, corrosive fluid transportation and other fields.
Disadvantages: (1) The pipe has poor low-temperature resistance and is brittle and easy to crack during winter construction. It is best to keep the operating environment temperature above 5°C, and it is strictly prohibited to throw it.
(2) Most of the raw materials are imported, which makes the price of pipes high and the sources of raw materials are limited, which sometimes inevitably hinders production.
(3) The surface hardness of the pipe is low, so it needs to be handled with care during transportation and construction, otherwise it will easily damage the surface and affect the appearance.
(4) The current pipe diameter specifications are only Ф16 mm to Ф160 mm (Ф160 mm pipes are too expensive and difficult to install and have few practical applications). Compared with the pipe specifications required for actual projects, there is still a large gap distance.
(5) Pipe fittings have poor compatibility and poor versatility. Different manufacturers have different forms and colors, which affects installation, acceptance and aesthetics.
(6) Hot melt connection requires professional installers and special tools, which can cause difficulties in installation when the operating space is narrow.
(7) The thermal expansion coefficient of the pipe is large. When the temperature is above 70°C, the pipe is easy to bend and deform, which affects the use effect and service life.
(8) It is not flame retardant and cannot be used for fire pipes and gas pipes.
2. Advantages of block copolymer (PP-B) pipe: (1) Recyclable, non-toxic, tasteless, green and environmentally friendly. (2) Hot melt connection, easy construction, no leakage, saving labor and time. (3) Pipes can be installed exposed or concealed. (4) The price of pipes is low, economical and practical. (5) It has good resistance to stress cracking in low-temperature environments and can be used at temperatures between -20°C and 60°C.
(6) Generally used as cold water pipes and corrosion-resistant pipes. Disadvantages: (1) It has poor high temperature resistance and cannot be used as high temperature pipes such as heating. (2) The current pipe diameter specifications are only Ф16 mm to Ф110 mm, which is too small.
(3) The pipe fittings have poor matching and poor versatility, which brings certain difficulties to the installation and acceptance.
(4) Hot melt connection requires professional installers and special tools. When the operating space is small, it will cause difficulties in installation.
(5) It is not flame retardant and cannot be used for fire protection pipelines and gas pipelines.
(6) The thermal stretchability and secondary maintenance problems of pipes are difficult to solve.
3. Advantages of aluminum nitride ceramic: (1) There is an aluminum layer in the middle of the pipe, which is impermeable to oxygen and will not corrode steel radiators and steel wall-mounted boilers.
(2) It has good toughness and can be bent within the allowable bending radius to reduce resistance.
(3) Can be supplied in coils, bringing convenience to transportation and storage.
(4) Installation is easy and fast, saving time and effort.
(5) Hot water aluminum-plastic pipes can withstand high temperatures up to 95°C.
(6) Widely used in hot and cold water pipes, floor heating, heating, compressed air pipes, corrosion-resistant pipes, etc.
Disadvantages: (1) The price of pipes and pipe fittings is high, and the project cost is correspondingly high.
(2) The current pipe diameter is only Ф16 mm to Ф75 mm, and the performance and price are relatively low.
(3) Pipes are mechanically connected using a ferrule or clamp type. Pipes and pipe fittings are made of different materials and made by different manufacturers, which often lead to leakage at pipe connections due to mismatched specifications and different thermal expansion coefficients. In addition, the country has not yet promulgated unified standards for aluminum-plastic pipes and pipe fittings, resulting in uneven physical and hygienic performance of pipes and pipe fittings. In addition, the quality of some construction teams is poor, resulting in the current aluminum-plastic pipe market being extremely chaotic. These These factors have greatly hindered the normal development of the aluminum-plastic pipe market.
(4) The pipe processing technology, especially the aluminum laser welding and hot melt adhesive bonding processes, is difficult to control, which sometimes causes delamination of the pipe, reduces the pressure-bearing capacity, and affects the service life.
(5) The pipeline is exposed and difficult to straighten, affecting its appearance.
(6) Pipe fittings have incomplete specifications and poor matching.
(7) Pipes are not easy to recycle, especially hot water pipes, which increase costs invisibly.
4. Advantages of cross-linked polyethylene (PE-X) pipe: (1) Lower cost and low construction cost. (2) It has good toughness and can be bent within the allowable bending radius to reduce resistance.
(3) Can be supplied in coils, bringing convenience to transportation and storage.
(4) Installation is easy and fast, saving time and effort.
(5) High temperature resistance up to 95℃.
(6) Generally used in hot water pipes, floor heating, heating pipes, etc.
Disadvantages: (1) At present, the pipe diameter is generally Ф16 mm to Ф25 mm, and most of them are used for floor heating.
(2) The pipes and pipe fittings are mechanically connected by clamping sleeves, and the pipe connections are prone to leakage.
(3) Pipe fittings have incomplete specifications and poor matching.
(4) Pipes are not recyclable and the unit cost is high.
(5) When pure water passes through the pipeline, odor will be generated.
(6) The pipe requires secondary cross-linking, and the processing technology is cumbersome. 5. Advantages of polyethylene (PE) pipes: (1) The price of pipes is low, the project cost is low, and the service life is long.
(2) Pipes with diameters below Ф63 mm can be supplied in coils. Pipes with diameters above Ф63 mm can be up to 12 meters in length. The cost of pipe fittings connection can be reduced accordingly during construction.
(3) Pipes and fittings are connected by hot-melt sockets, hot-melt butt joints, and electric fusion, which are high-strength, solid and reliable, and do not leak.
(4) It has good toughness and can be bent as needed during construction, reducing the number of pipe fittings and reducing the cost. Especially in mountainous areas, the construction can be connected at any angle according to the terrain trend, making the construction simple and fast.
(5) Since pipe welding can be performed on the ground, the amount of earthwork required for pipe trench excavation during construction is about 2/3 of that of ordinary steel pipes, which greatly reduces construction costs.
(6) The construction operation is simple and the sheet metal welding speed is fast. Compared with ordinary steel pipes, the construction period can be shortened by nearly 1/2, which greatly improves the construction efficiency.
(7) Generally used in low-pressure gas and low-pressure water supply pipelines. The pipes can be sunk into the bottom of rivers, rivers, and lakes for construction using the pile driving method, which is unmatched by other pipes. The toughness of the pipes itself can also be used to penetrate the PE pipes into the original waste pipes during the renovation of urban pipe networks. , thereby avoiding a series of adverse effects caused by ground excavation and truly benefiting the people. As the service life of the original water supply and gas pipelines in cities and towns gradually expires, the widespread application of PE pipelines will paint a brilliant blueprint for people.
Disadvantages: (1) The pipe has low pressure and cannot be used for high-pressure main lines transporting water supply and gas.
(2) There are still very few domestic manufacturers of electrofusion pipe fittings that have truly passed the quality standard. Most of them rely on imports, and the matching and completeness of pipe fittings still needs further research and development.
(3) The material of the pipe is soft. When backfilling the soil after installation, except for the normal construction procedures, it is strictly prohibited to backfill the pipe with sharp objects to avoid damage to the pipe.
(4) The raw materials of PE80 and PE100 are still imported from abroad, which virtually increases the cost of the pipeline itself.
In summary, although aluminum-plastic pipes, PP-R pipes, PP-B pipes, PE-X pipes, and PE pipes have their own shortcomings to varying degrees in actual engineering applications, they are still popular among designers, It is favored by construction workers and people, and with an unstoppable and gratifying momentum, it has reached the forefront of the development of new chemical building materials. Each of our engineering and technical personnel should choose and use different types of economical and reasonable pipes according to the different conditions of each project, so that the installers can worry less and the users can feel at ease. At the same time, they can communicate and feedback project information in a timely manner, so as to provide new Contribute to the smooth promotion and continuous improvement of chemical pipes.