Ring stiffness is a core indicator for measuring the ability of a pipeline to resist deformation under external pressure (such as soil pressure, traffic load), with the unit of kN/m², indicating the deformation resistance of the pipeline under vertical load.
Formula:
Ring stiffness (SN) = EID3Ring stiffness (SN) = D3EI
EE: Material elastic modulus
II: Pipe section moment of inertia
DD: Pipe diameter
International general standards (such as ISO 9969, ASTM D2412) classify ring stiffness into the following grades:
Grade | Ring Stiffness (kN/m²) | Application Scenarios |
SN2 | ≥2 | Low-load areas (e.g., green space drainage) |
SN4 | ≥4 | Light-duty roads, residential drainage |
SN8 | ≥8 | Municipal roads, general traffic areas |
SN12.5 | ≥12.5 | Heavy vehicle traffic (e.g., highways) |
SN16 | ≥16 | Ultra-deep burial or extreme load conditions |
Pipe structure:
Solid wall pipe: high stiffness, suitable for high-pressure scenarios (such as SN8 and above).
Double-wall corrugated pipe: hollow structure is lightweight, but can reach SN4-SN8 through corrugated design.
Steel belt reinforced pipe: composite steel belt support, can reach SN12.5-SN16.
Material density: The density of HDPE raw material (usually ≥0.941g/cm³) directly affects rigidity.
Wall thickness design: Under the same diameter, increasing wall thickness can significantly improve ring stiffness.
Buried depth <1m: SN4 (such as courtyard drainage).
Buried depth 1-3m: SN8 (municipal road).
Buried depth >3m or heavy load: SN12.5-SN16 (need to be calculated in combination with soil quality).
Dynamic load: areas with frequent traffic need to increase by 1-2 levels (such as SN8→SN12.5).
Laboratory test: Perform three-point loading test according to ISO 9969 to measure the deformation rate of pipes.
On-site verification: Deformation rate detection is required after construction (usually required to be ≤5%).
Certification standards:
National standard: GB/T 19472.1 (buried polyethylene double-wall corrugated pipe)
European standard: EN 13476 (structural wall pipe system)
Misunderstanding 1: The higher the ring stiffness, the better?
→ Excessive pursuit of high stiffness may increase costs, and it is necessary to balance load requirements and economy.
Misunderstanding 2: HDPE pipe flexibility = low stiffness?
→ Structural design (such as corrugation, reinforcement layer) can take into account flexibility and high stiffness.
Construction points:
Backfill materials should use coarse sand or gravel to avoid sharp stones damaging the pipe wall.
Layer compaction to prevent local stress concentration.
Pipe Type | Typical Ring Stiffness (kN/m²) | Characteristics |
HDPE Double-Wall Corrugated Pipe | SN4–SN8 | Lightweight, economical, suitable for general drainage |
HDPE Steel Belt Reinforced Pipe | SN8–SN16 | Ultra-high strength, ideal for deep burial or heavy load conditions |
PVC Solid Wall Pipe | SN2–SN4 | High rigidity but poor impact resistance |
Concrete Pipe | ≥20 | Heavy and costly to install |
The ring stiffness level of HDPE pipe directly determines its engineering applicability. When selecting, it is necessary to comprehensively evaluate the burial depth, load, soil quality and cost. For high-demand scenarios (such as municipal trunk roads), it is recommended to choose SN8 or above and match it with a steel belt reinforcement structure to ensure long-term stability.
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PE100 grade HDPE pipe refers to pipes made of PE100 grade in high-density polyethylene (HDPE) material.
PE (Polyethylene) Grading: HDPE materials are divided into different grades according to density, mechanical properties and pressure resistance, and the common ones are PE32, PE63, PE80 and PE100.
PE100 is the highest performance grade at present, with higher compressive strength, crack propagation resistance and long-term durability.
The number (such as 100) represents the minimum required strength (MRS) in MPa. The MRS of PE100 is 10 MPa, which is an upgraded version of PE80 (8 MPa).
High strength: can withstand higher pressure (common pressure grades: PN10, PN16, etc.), suitable for high-pressure scenarios such as water and gas transmission.
Chemical corrosion resistance: Resistant to acids, alkalis, salts and other chemicals, suitable for industrial wastewater systems.
Lightweight and flexible: Lightweight (only 1/8 of metal pipes), easy to transport and install, and can be bent to adapt to the terrain.
Long life: Design life can reach more than 50 years, UV resistance (if carbon black is added) and environmental stress cracking resistance.
Environmentally friendly and non-toxic: Meets drinking water standards (such as ISO 4427) and is often used in water supply networks.
Water supply system: municipal tap water, direct drinking water pipeline.
Gas transmission: medium and low pressure gas pipeline network (must comply with standards such as ISO 4437).
Industrial pipeline: chemical fluid, slurry transportation.
Drainage/sewage system: strong corrosion resistance, suitable for rainwater and sewage discharge.
Feature | PE100 | PE80 |
Minimum Required Strength (MRS) | 10 MPa | 8 MPa |
Pressure Capacity | Higher (achieves same pressure with thinner wall) | Lower |
Crack Resistance | Superior | Moderate |
Cost | Slightly higher | Lower |
ISO 4427: Production and testing standard for PE100 water supply pipes.
EN 12201: European standard for HDPE pipes for water supply.
GB/T 13663: National standard for PE pipes for water supply in China.
PE100 grade HDPE pipes have become the preferred material for modern pipeline engineering due to their high strength, corrosion resistance and long life, especially suitable for high-pressure and high-demand application scenarios. When choosing, pay attention to the certification standards (such as ISO or GB) and the actual working conditions.
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According to experts, HDPE pipes have been widely used in municipal water supply, underground pipe networks, and large-scale construction projects due to their excellent flexibility, corrosion resistance and ultra-long service life. HDPE pipes have excellent impact resistance and resistance to geological settlement. They can achieve overall system leakage-free through hot-melt connection and are considered to be one of the safest and most reliable water supply solutions at present.
In contrast, PPR pipes are mainly used in hot and cold water pipe systems in buildings. PPR pipes are light in material, simple to construct, and have good high temperature resistance. They are suitable for water supply and heating systems in home decoration. Because its connection method also uses hot-melt technology, it can ensure that the interface is firm and not easy to leak, so it has a wide market in residential areas and office buildings. Internal water supply systems.
In the performance comparison, HDPE pipes show stronger comprehensive advantages. First, HDPE pipes are far more resistant to low-temperature impact than PPR, and can maintain good toughness even in cold environments. Second, HDPE pipes are more resistant to ultraviolet rays and are suitable for outdoor laying. Most importantly, HDPE pipes have a wider range of sizes and specifications, which can meet the needs of water supply projects of different sizes.
However, experts also pointed out that the high temperature tolerance of PPR pipes is excellent in daily household water use (especially hot water systems), and is more economical and practical in small-diameter water supply applications. Therefore, when selecting materials, comprehensive considerations should be made based on the actual application environment, operating temperature, construction conditions and budget.
An engineer from the China Academy of Building Research said: "If it is indoor water supply, especially inside residential buildings, PPR pipes are very cost-effective, easy to install and have low maintenance costs. If it is municipal water supply, long-distance water delivery or occasions with high weather resistance requirements, HDPE pipes are a better choice."
At present, many pipeline manufacturers are also constantly innovating material technology and launching a variety of specifications and composite products to meet the needs of different application scenarios. Industry insiders remind consumers and project parties that when choosing pipes, they should choose products that meet national standards and be installed by professional construction teams to ensure the safety and stability of the water supply system.
In the future, as urban infrastructure construction and smart home development put forward higher requirements for water systems, the application of HDPE pipes and PPR pipes in their respective fields will continue to expand, and how to accurately select materials according to demand will become an important part of ensuring water safety.
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Company address: Room 802, 8th Floor, Building 5, Jinyin Modern City, Jinshui District, Zhengzhou City, Henan Province, China
With the continuous development of construction engineering and home decoration industries, the selection of pipe materials has become an important issue of concern to users. Especially in water supply systems, HDPE (high-density polyethylene) pipes and PPR (random copolymer polypropylene) pipes are widely used due to their good performance. But which pipe is more suitable for water supply? Recently, many industry experts have conducted in-depth analysis on this topic.
According to experts, HDPE pipes have been widely used in municipal water supply, underground pipe networks, and large-scale construction projects due to their excellent flexibility, corrosion resistance and ultra-long service life. HDPE pipes have excellent impact resistance and resistance to geological settlement. They can achieve overall system leakage-free through hot-melt connection and are considered to be one of the safest and most reliable water supply solutions at present.
In contrast, PPR pipes are mainly used in hot and cold water pipe systems in buildings. PPR pipes are light in material, simple to construct, and have good high temperature resistance. They are suitable for water supply and heating systems in home decoration. Because its connection method also uses hot-melt technology, it can ensure that the interface is firm and not easy to leak, so it has a wide market in residential areas and office buildings. Internal water supply systems.
In the performance comparison, HDPE pipes show stronger comprehensive advantages. First, HDPE pipes are far more resistant to low-temperature impact than PPR, and can maintain good toughness even in cold environments. Second, HDPE pipes are more resistant to ultraviolet rays and are suitable for outdoor laying. Most importantly, HDPE pipes have a wider range of sizes and specifications, which can meet the needs of water supply projects of different sizes.
However, experts also pointed out that the high temperature tolerance of PPR pipes is excellent in daily household water use (especially hot water systems), and is more economical and practical in small-diameter water supply applications. Therefore, when selecting materials, comprehensive considerations should be made based on the actual application environment, operating temperature, construction conditions and budget.
An engineer from the China Academy of Building Research said: "If it is indoor water supply, especially inside residential buildings, PPR pipes are very cost-effective, easy to install and have low maintenance costs. If it is municipal water supply, long-distance water delivery or occasions with high weather resistance requirements, HDPE pipes are a better choice."
At present, many pipeline manufacturers are also constantly innovating material technology and launching a variety of specifications and composite products to meet the needs of different application scenarios. Industry insiders remind consumers and project parties that when choosing pipes, they should choose products that meet national standards and be installed by professional construction teams to ensure the safety and stability of the water supply system.
In the future, as urban infrastructure construction and smart home development put forward higher requirements for water systems, the application of HDPE pipes and PPR pipes in their respective fields will continue to expand, and how to accurately select materials according to demand will become an important part of ensuring water safety.
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Contact us: Email:inquiry@phtopindustry.com | Whatsapp:+86 15093100892
Company address: Room 802, 8th Floor, Building 5, Jinyin Modern City, Jinshui District, Zhengzhou City, Henan Province, China
HDPE and PVC have their own advantages in durability, depending on the use environment and application requirements. The following is a comparative analysis of the two:
HDPE pipe (high-density polyethylene) has higher flexibility and impact resistance, especially in low-temperature environments (can withstand -60°C to 60°C), and is not easy to crack.
PVC pipe (polyvinyl chloride) has higher hardness, but is more brittle and may crack at low temperatures or when impacted by external forces.
HDPE pipe has stronger resistance to most acids, alkalis and chemicals, and is suitable for corrosive environments such as chemical industry and wastewater treatment.
PVC pipe has good acid and alkali resistance, but may deteriorate in strong oxidizing acids (such as concentrated sulfuric acid) or organic solvent environments.
The wear resistance of HDPE pipe is 4 times that of steel pipe. It is suitable for high wear scenarios such as mud transportation, and the theoretical service life can reach more than 50 years.
PVC pipe has better wear resistance, but not as good as HDPE. The service life is usually about 50 years, but it is more susceptible to ultraviolet rays.
HDPE pipe can withstand high temperatures of 95°C for a long time and 110°C for a short time, which is suitable for hot water transportation.
PVC pipe has poor temperature resistance and is generally only suitable for environments below 60°C. It is easy to soften and deform at high temperatures.
HDPE pipe adopts hot melt connection, with high joint strength and good seismic resistance, which is suitable for underground or complex terrain laying.
PVC pipe adopts adhesive or threaded connection, which is easy to install, but the joint may become a weak point.
HDPE pipe has stronger comprehensive durability, especially suitable for low temperature, high corrosion, high wear and scenes requiring flexibility (such as underground pipelines and chemical transportation). PVC pipes are economical and suitable for water supply and drainage at room temperature and low pressure, wire protection and other applications, but they are not as durable as HDPE in extreme environments.
If you need long-term durability, impact resistance, and chemical corrosion resistance, choose HDPE pipes.
If the budget is limited and it is used for ordinary water supply and drainage, PVC pipes are still a good choice.
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