PVC water supply pipes and drainage pipes

PVC water supply pipes and drainage pipes are two common plastic pipes with different applications in building water supply and drainage systems. They differ in raw materials, pressure levels, appearance, connection methods and other aspects. The following is a detailed introduction for you:

1. Raw materials and formula

PVC water supply pipe

: Usually uses sanitary polyvinyl chloride resin as the main raw material, adds appropriate amounts of stabilizers, lubricants, fillers and other additives, and is processed by mixing, plasticizing, extrusion and other processes. In order to ensure water quality safety, the raw materials and additives used in water supply pipes must comply with relevant health standards. For example, GB/T 10002.1 "Hard polyvinyl chloride (PVC-U) pipes for water supply" has strict regulations on the sanitary properties of raw materials to ensure that the water quality will not be polluted when transporting drinking water and other domestic water.

PVC drainage pipe

: Generally, polyvinyl chloride resin is used as the basic raw material, but some recycled materials or relatively low-cost additives may be used in the formula. This is because the drainage pipe has relatively low requirements for sanitary performance, mainly considering its drainage function and durability.

For example, in some non-drinking water drainage systems, in order to reduce costs, a certain proportion of recycled materials can be appropriately added, but the physical properties and chemical stability of the pipes must be guaranteed to meet the drainage requirements.

2. Pressure level

PVC water supply pipe: It needs to withstand a certain water pressure, so there are strict requirements for the pressure level. Common pressure levels are 0.6MPa, 0.8MPa, 1.0MPa, 1.25MPa, 1.6MPa, etc.

Pipes with different pressure levels are suitable for different water supply systems. For example, in urban water supply networks, water supply pipes with appropriate pressure levels are generally selected according to the water pressure conditions in different areas.

In high-rise buildings, since the bottom pipes need to withstand greater water pressure, PVC water supply pipes with higher pressure levels are usually selected to ensure that the pipes will not break during long-term use. Safety problems such as rupture.

PVC drainage pipes: Mainly used for discharging sewage and rainwater, etc., generally do not need to withstand very high pressure, and their pressure levels are relatively low, usually around 0.2MPa 0.4MPa. This is because the water flow rate and pressure in the drainage system are relatively small, and the pressure resistance requirements for the pipes are not as high as those for the water supply pipes.

For example, in the household drainage system, the drainage pipes in the bathroom, kitchen and other parts only need to meet the pressure requirements during normal drainage. The lower pressure level can meet the use needs and reduce costs.

3. Appearance

PVC water supply pipe

: Generally white or blue, with a smooth surface and uniform color. This is because the water supply pipe needs to be kept clean and sanitary. Light colors such as white or blue are conducive to observing the internal conditions of the pipe, and also give people a clean and hygienic feeling. The wall thickness of the pipe is relatively thick and uniform, which is to ensure that the pipe can withstand the corresponding water pressure.

PVC drainage pipe

: Usually gray or black, because the drainage pipe does not have high requirements for the appearance color. Gray or black can cover some defects that may occur in the production and use of the pipe, and also has a certain weather resistance. The wall thickness of the drainage pipe is relatively thin, which is determined by its use environment and function.

In some special occasions, such as the drainage of the building facade that requires beautiful appearance, there will also be white or other colors of PVC drainage pipes, but relatively few.

4. Specifications and dimensions

PVC water supply pipe

: The specifications and dimensions are usually standardized and uniform. Common nominal outer diameters are 20mm, 25mm, 32mm, 40mm, 50mm, 63mm, 75mm, 90mm, 110mm, etc. The wall thickness varies according to the pressure level. Generally speaking, the higher the pressure level, the thicker the wall thickness.

For example, a PVC water supply pipe with a nominal outer diameter of 63mm may have a wall thickness of 2.0mm at a pressure level of 0.6MPa; and at a pressure level of 1.6MPa, the wall thickness may reach 4.7mm.

PVC drainage pipe

: The specifications and dimensions are also quite diverse. Common nominal outer diameters are 50mm, 75mm, 110mm, 160mm, 200mm, 250mm, 315mm, etc.

Compared with water supply pipes, the nominal outer diameter of drainage pipes is relatively large, which is to meet the demand for drainage flow. Its wall thickness is relatively thin, and the change of wall thickness is relatively small under different nominal outer diameters.

For example, the wall thickness of a PVC drainage pipe with a nominal outer diameter of 110mm may be between 3.2mm and 4.0mm.

5. Connection method

PVC water supply pipe

Glue bonding

: For small-diameter PVC water supply pipes, glue bonding is often used. This connection method is to apply special PVC glue on the surface of the socket and the plug of the pipe, and then quickly insert the plug into the socket, and wait for the glue to solidify to form a firm connection.

The advantages of glue bonding are firm connection and good sealing, which can effectively prevent water leakage.

Hot melt connection

: In some occasions, hot melt connection is also used. The connection part of the pipe is heated to a molten state by a heating tool, and then the two connection parts are quickly docked and a certain pressure is applied. After cooling, the connection can be achieved.

The advantages of hot melt connection are high connection strength and good integrity of the pipe connection, but it has high requirements for construction technology and equipment.

Flange connection

: For large-diameter PVC water supply pipes or parts that need to be disassembled frequently, flange connection is often used. Fix the flanges at the ends of the two pipes respectively, then connect the two flanges together with bolts, and install a sealing gasket in the middle to ensure the sealing of the connection.

PVC drainage pipe

Glue bonding

: Small-diameter PVC drainage pipes are also often glued. The operation method is similar to that of water supply pipes, but since the drainage pipes have relatively low pressure sealing requirements, the performance requirements of the glue may be slightly different.

Rubber ring connection

: For large-diameter PVC drainage pipes, rubber ring connection is a common method. Install a rubber ring at the socket of the pipe, and then insert the socket into the socket. The rubber ring plays a sealing and buffering role during the pipe connection process.

This connection method is easy and quick to install, and has a certain degree of flexibility, which can adapt to slight deformation of the pipe.

Spiral connection

: Some special types of PVC drainage pipes use spiral connection. The end of the pipe has a spiral structure, and the two pipes are connected together by rotation.

This connection method is fast to install and does not require the use of glue or other sealing materials, but it requires high processing accuracy of the pipe.

6. Application

PVC water supply pipe

: Mainly used to transport various fluid media such as drinking water, domestic water, industrial water, etc. In the urban water supply network, many water supply pipes from water plants to residential areas, commercial buildings, etc. use PVC water supply pipes. Inside the building, PVC water supply pipes are also often used for cold and hot water supply pipes in bathrooms, kitchens, etc.

In addition, in some industrial production, such as chemical and electronic industries, PVC water supply pipes may also be used for pipes used to transport some process water with high water quality requirements

PVC drainage pipe

: Mainly used to discharge domestic sewage, industrial wastewater, rainwater, etc. In the building drainage system, PVC drainage pipes are usually used for sewage discharge pipes in bathrooms and kitchens, as well as roof rainwater discharge pipes. In municipal drainage projects, PVC drainage pipes are also widely used in rainwater drainage pipes and sewage drainage pipes under urban roads. Its good corrosion resistance and drainage performance can ensure the long-term stable operation of the drainage system.

7. Performance characteristics

PVC water supply pipe

Good sanitation performance

: It uses sanitary raw materials and meets relevant health standards. It will not pollute the water quality of the water and can ensure the safety and hygiene of drinking water.

Strong corrosion resistance

: It has good acid and alkali resistance and chemical corrosion resistance, can resist the erosion of various chemical substances in the water, and extend the service life of the pipe.

High pressure resistance

: It is designed according to different pressure levels and can withstand high water pressure to meet the needs of different water supply systems.

Low water flow resistance

: The inner wall of the pipe is smooth and the water flow resistance is small, which can reduce the energy loss in the water supply process and improve the water supply efficiency.

PVC drainage pipe

Strong drainage capacity

: The large-diameter drainage pipe can meet the large drainage flow requirements and ensure that sewage and rainwater can be discharged quickly.

Good wear resistance

: Although the pressure requirement is not high, it may be washed by impurities in the water flow during the drainage process. It has good wear resistance and can ensure the long-term use of the pipe.

Good sound insulation performance

: PVC material itself has a certain sound insulation effect, which can reduce the noise generated during drainage and improve the comfort of living and working environment.

Easy installation

: The connection methods are diverse and relatively simple, light in weight, easy to install, and can reduce construction costs and difficulties.

8. Inspection standards

PVC water supply pipe

Appearance inspection

: According to relevant standards, check whether the surface of the pipe is smooth, the color is uniform, and there are no defects such as bubbles, cracks, and depressions.

Dimension measurement

: Use tools such as calipers and wall thickness micrometers to measure the nominal outer diameter, wall thickness and other dimensions of the pipe to ensure that it meets the standard requirements.

Pressure test

: Conduct a water pressure test, fill the pipe with water, keep it at the specified pressure for a certain period of time, and observe whether the pipe has leakage, rupture, etc. For example, GB/T 10002.1 stipulates that the water pressure test pressure of the water supply pipe is 1.5 times the working pressure, but not less than 0.6MPa, and the pressure stabilization time is not less than 1 hour.

Sanitary performance test

: Perform sanitation performance test on the pipeline, including the test of heavy metal content, volatile content and other indicators to ensure that the pipeline will not pollute the water quality.

PVC drainage pipe

Appearance and size inspection

: Similar to the water supply pipe, check the appearance quality and size specifications of the drainage pipe to ensure that it meets the standard requirements.

Ring stiffness test

: Use the ring stiffness tester to apply radial pressure to the drainage pipe and measure the deformation of the pipe to evaluate its ring stiffness performance. Ring stiffness is an important indicator to measure the pressure resistance of the drainage pipe. Drainage pipes of different specifications and uses have corresponding ring stiffness requirements.

Sealing test

: Perform sealing tests, such as water-tightening test or air-tightening test, to check whether the drainage pipe has leakage. In the non-pressure drainage system, the water-tightening test is usually used to block both ends of the pipe, inject water into the pipe, and observe whether the water level drops within a certain period of time to judge the sealing of the pipe.