High-density polyethylene (HDPE) pipes have been widely used in water supply, drainage, natural gas transportation, agricultural irrigation, industrial fluid transportation and other fields due to their corrosion resistance, flexibility and strong impact resistance. When choosing HDPE pipes, the wall thickness is a key factor, which directly affects the pressure bearing capacity, service life and applicable scenarios of the pipe. This article will introduce the classification, standards and applications of HDPE pipe thickness in detail.
The thickness of HDPE pipes is usually classified according to different international standards (such as ISO 4427, ASTM D3035, EN 12201), mainly measured by SDR (Standard Dimension Ratio) or PN (Nominal Pressure).
SDR (Standard Dimension Ratio) = Outer Diameter ÷ Wall Thickness
The smaller the SDR value, the thicker the pipe wall and the stronger the pressure bearing capacity.
PN (nominal pressure, unit: MPa) indicates the working pressure that the pipeline can withstand, and the PN value of thick-walled pipes is higher.
Common HDPE pipe thickness grades:
|
SDR |
Wall thickness (relative to pipe diameter) |
PN |
Application Areas |
|
SDR 41 |
Thin wall |
PN 4 |
Gravity drainage, ventilation ducts |
|
SDR 33 |
Thin |
PN 5 |
Low pressure drainage, farmland irrigation |
|
SDR 26 |
Medium thickness |
PN 6 |
Municipal sewage, low pressure water supply |
|
SDR 21 |
Thick |
PN 8 |
General water supply pipeline |
|
SDR 17 |
Thick wall |
PN 10 |
Municipal water supply, industrial transportation |
|
SDR 13.6 |
Thicker |
PN 12.5 |
High-pressure water supply, mining transportation |
|
SDR 11 |
Extra thick |
PN 16 |
Natural gas pipelines, high pressure transmission |
|
SDR 9 |
Extra thick |
PN 20 |
High-pressure industrial fluid delivery |
(1) Pressure bearing capacity
The thicker the HDPE pipe wall, the stronger the pressure resistance of the pipe, which is suitable for high-pressure water supply, industrial liquid transportation, natural gas pipeline network and other fields. For example, HDPE dr11 pipe can withstand higher pressure than SDR 21 pipe.
(2) Durability and service life
Thicker pipe walls perform better in impact resistance, wear resistance, and environmental stress cracking resistance, and are suitable for underground burial and harsh environmental conditions, such as mining transportation, seawater transportation, petrochemical industry, etc.
(3) Ease of construction and installation
Although thick-walled pipes are stronger, they are also heavier and more difficult to bend, and the construction and transportation costs are relatively high. Thin-walled pipes (such as SDR 33 and SDR 41) are lighter and suitable for non-pressure drainage systems, such as gravity drainage, ventilation systems, rainwater discharge, etc.
1. Municipal water supply and drainage: SDR 21 ~ SDR 17 are suitable for urban water supply networks, and SDR 26 is used for sewage pipes.
2. Agricultural irrigation: SDR 33 ~ SDR 21 pipes are suitable for low-pressure drip irrigation and sprinkler irrigation systems.
3. Natural gas transportation: SDR 11 ~ SDR 9 HDPE pipes are widely used in gas pipe networks due to their corrosion resistance and no leakage.
4. Industrial liquid transportation: SDR 13.6 ~ SDR 9 are suitable for chemical fluids and high-pressure slurry transportation.
5. Seawater desalination and submarine pipelines: SDR 17 ~ SDR 11 HDPE pipes have excellent corrosion resistance and are suitable for seawater transportation.
When choosing HDPE pipe, the following factors need to be considered comprehensively:
1. Working pressure: If the pipe needs to withstand higher pressure, such as high-pressure water supply and natural gas transmission, pipes with SDR 13.6 or lower should be selected.
2. Environmental conditions: Underground burial and mining applications require thick-walled pipes (such as SDR 11), while surface drainage can use thinner SDR 26 or higher.
3. Cost and construction: Thick-walled pipes are more expensive and complex to construct, and the service life and installation convenience need to be weighed.
The thickness of HDPE pipe directly determines its pressure bearing capacity, durability and application scenarios. In different fields such as municipal construction, agricultural irrigation, and industrial transportation, the reasonable selection of pipe wall thickness is crucial to ensure the quality of the project. Whether it is high-pressure water supply, gas transmission, or low-pressure irrigation and drainage systems, the correct selection of HDPE pipe thickness will optimize pipeline performance and improve return on investment.
