PVC pipe (polyvinyl chloride pipe) because of its excellent physical and chemical properties, widely used in water pipes, cable protection pipes, chemical delivery pipes and other fields. When using PVC pipe, PVC pipe id size is a crucial parameter, which directly affects the fluid transport capacity of the pipeline, the ease of installation of the pipeline and the overall performance of the system. This paper will discuss the selection, standard, application and influencing factors of PVC pipe id size in detail.

Definition and significance of PVC pipe inner diameter
PVC pipe id size (Inner Diameter, referred to as ID) refers to the inner cavity size of the pipe, usually expressed in millimeters (mm) or inches (inches). It is the actual channel size of the fluid flow in the pipe, which directly determines the flow rate and fluid flow rate.
The inner diameter size is crucial to the design and selection of the pipe. An excessively large inner diameter will result in a low fluid flow rate and increase the maintenance cost of the system; while an excessively small inner diameter will result in a too fast flow rate, generate greater resistance, reduce the efficiency of the system and may cause damage to the pipe. Therefore, choosing the right inner diameter size is crucial to ensure the normal operation of the system.

The relationship between the inner diameter and outer diameter of PVC pipes
The size of PVC pipes is usually determined by the inner diameter (ID) and the outer diameter (OD). The outer diameter is the external dimension of the pipe and is usually standardized, while the inner diameter varies according to the wall thickness. The wall thickness of PVC pipes is generally designed according to the pressure level it withstands. Therefore, the thicker the wall thickness, the smaller the inner diameter will be under the same outer diameter.
When selecting PVC pipes, it is usually necessary to comprehensively consider factors such as flow requirements, pressure levels, and pipe length to select the appropriate inner diameter size. The common outer diameter and inner diameter matching relationship of PVC pipes is shown in the table:
Outer diameter (OD, mm) | Inner diameter (ID, mm) | Wall thickness (mm) |
20 | 16 | 2 |
25 | 20 | 2.5 |
32 | 26 | 3 |
40 | 32 | 4 |
50 | 40 | 5 |
63 | 50 | 6 |
Depending on the outer diameter, the inner diameter of the PVC pipe can be different. Consumers and engineering designers need to choose the appropriate pipe specifications based on actual usage requirements.
Selection basis of PVC pipe id size
When selecting PVC pipe id size, multiple factors need to be considered, including the flow requirements, installation space, pressure bearing capacity of the pipeline, etc. The following are some common selection bases:
1. Flow requirements
The inner diameter size directly determines the flow rate that the pipeline can transport. When a large flow rate needs to be transported, the inner diameter must be large enough to ensure that the fluid can pass smoothly. The flow calculation formula is usually:
Q=A×vQ = A \times vQ=A×v
Where Q is the flow rate (cubic meters/second), A is the cross-sectional area of the pipeline, and v is the flow velocity (meters/second). The flow velocity is closely related to the inner diameter of the pipeline. If a larger flow rate is required, a larger inner diameter must be selected.
2. Hydraulic loss
Hydraulic loss is the energy loss caused by friction and other factors in the fluid in the pipeline. Pipes with smaller inner diameters have higher flow rates and greater friction losses; while pipes with larger inner diameters have lower flow rates and smaller hydraulic losses. When designing a pipeline system, it is necessary to comprehensively consider economy and efficiency, select a suitable inner diameter size, and avoid excessive hydraulic losses.
3. System pressure
The inner diameter of the PVC pipe is also closely related to the pressure the pipe is subjected to. In high-pressure systems, it is usually necessary to select pipes with larger inner diameters to reduce pipe damage or water hammer caused by excessive flow.
4. Installation space
In some applications, the installation space is limited, so the inner diameter of the pipe must match the available space. For example, when installing water pipes in a building, it may be necessary to select the appropriate inner diameter size based on the spatial layout of the room and the direction of the pipe.

Standards and specifications for the inner diameter of PVC pipes
PVC pipe id size is usually regulated by national or international standards. PVC pipes in different regions and for different purposes may have different standards. For example:
Chinese Standard (GB/T 10002.1-2006): This standard specifies the outer diameter, inner diameter, wall thickness and other parameters of PVC-U pipes, and is applicable to the design and use of pipes such as water supply and drainage.
International Standard (ISO 1452): This standard applies to PVC pipes in construction, water supply, drainage and other systems, and specifies the size, wall thickness, pressure level and other requirements of the pipes.
American Standard (ASTM D1785): This standard applies to PVC-U pipes, involving the size, material, performance testing and other aspects of the pipes.
These standards provide a basis for the production and use of PVC pipes, ensuring the quality and performance of the pipes.

Application Examples
1. Water Supply Pipes
PVC Pipes for Water are commonly used for water supply pipes in residential and industrial water systems. For household water pipes, common pipe sizes are 20mm, 25mm and 32mm, with inner diameters of 16mm, 20mm and 26mm, respectively. For industrial water systems, larger PVC pipes, such as 50mm or larger pipes, may need to be selected to ensure sufficient water flow.
2. Drainage Systems
PVC pipes are widely used in drainage systems, including sewage discharge, rainwater discharge, etc. The common inner diameter of drainage pipes is generally 50mm, 63mm or larger, depending on the length of the pipe and the amount of drainage.
3. Cable Protection Pipes
In power systems, PVC pipes are used to protect cables from damage by the external environment. The inner diameter of the cable protection pipe is usually selected according to the outer diameter of the cable to ensure that the cable can pass smoothly without damage.
PVC pipe id size is one of the key parameters in pipeline design, which directly affects the flow, pressure, service life and maintenance cost of the pipeline. When selecting PVC pipes, it is necessary to comprehensively consider factors such as flow demand, pressure requirements, hydraulic loss, installation space, etc. to select the appropriate inner diameter size. Through scientific and reasonable inner diameter selection, the working efficiency of the pipeline system can be improved and its long-term stable operation can be ensured. Therefore, it is very important for engineering designers and users to understand the relevant standards and calculation methods of the inner diameter size of PVC pipes.