HDPE (high-density polyethylene) pipes play a vital role in sponge city construction. Their excellent physical properties, environmental protection characteristics and convenient construction make them the core materials for modern urban drainage, rainwater management and ecological restoration. The following is an analysis of the core role of HDPE pipes in sponge city construction and their advantages:
One of the core goals of sponge cities is to solve the problem of urban waterlogging. HDPE pipes can significantly improve drainage efficiency and reduce the risk of blockage due to their smooth inner wall and low friction coefficient. Compared with traditional concrete pipes, HDPE pipes have stronger water-passing capacity and can deliver larger flows at the same pipe diameter, or use smaller pipe diameters at the same flow rate to reduce project costs.
In addition, HDPE pipes are suitable for rainwater collection and reuse systems, such as:
Permeable pavement and rainwater gardens: HDPE pipes can connect permeable pavements and reservoirs to achieve rapid infiltration and storage of rainwater.
Recycled water reuse system: Some sponge city projects (such as Wuxi, Jiangsu) use HDPE pipes to use treated rainwater for greening irrigation or road washing to reduce water waste.
HDPE pipes have excellent chemical corrosion resistance and can resist the erosion of acids, alkalis, salts and industrial wastewater, and are suitable for complex underground environments. Its service life can reach more than 50 years, which is much longer than traditional concrete pipes and cast iron pipes, reducing the economic and environmental burden caused by frequent replacement.
Sponge city construction often involves soft soil foundations or areas prone to settlement. The high flexibility and impact resistance of HDPE pipes enable them to adapt to uneven settlement, and even maintain structural integrity under extreme conditions such as earthquakes, avoiding leakage problems caused by pipe rupture.
Recyclable: HDPE materials are recyclable and in line with the green and low-carbon development concept of sponge cities.
Reducing secondary pollution: The inner wall of HDPE pipes is smooth, not easy to scale or breed bacteria, avoiding water pollution, and is particularly suitable for drinking water and rainwater recycling systems.
Lightweight design: HDPE pipes are light in weight, easy to transport and install, and reduce construction difficulty and mechanical requirements.
Flexible connection method: hot melt or electric fusion connection is used to ensure the sealing of the interface and reduce the risk of leakage.
Low comprehensive cost: Although the initial investment may be high, the long-term maintenance cost is low, and the overall economic benefits are better than traditional pipes.
The application of HDPE pipes in sponge city construction includes:
Municipal drainage and sewage systems (such as the sponge city pilot in Changde, Hunan).
Industrial wastewater discharge (corrosion resistance makes it suitable for chemical, mining and other fields).
Agricultural irrigation and saline-alkali land improvement (such as fishery water supply and salt brine supply).
Road and tunnel drainage (strong pressure resistance and can withstand vehicle loads).
HDPE pipes have become an indispensable key material in sponge city construction due to their corrosion resistance, high flexibility, environmental protection and ease of construction. It not only improves the efficiency of urban drainage systems, but also supports the resource utilization of rainwater, helping cities achieve the ecological goals of "water absorption, water storage, water infiltration and water purification".
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HDPE pipes (high-density polyethylene pipes) are widely used in agricultural irrigation due to their corrosion resistance, aging resistance, good flexibility, and convenient construction. Reasonable selection of pipe diameter and pressure level can effectively improve irrigation efficiency, reduce costs, and extend service life. This article will systematically introduce the selection method of HDPE pipes in agricultural irrigation from three aspects: selection principle, diameter calculation, and pressure level determination.
1. Meet the irrigation flow demand
The pipe diameter must ensure sufficient flow to avoid excessive hydraulic loss due to too small a diameter, which will affect the irrigation effect.
2. Ensure water delivery pressure
According to the terrain height difference, pipe length, and terminal equipment requirements, reasonably select the pressure level to avoid pipe bursting or insufficient water pressure.
3. Take into account economy
The larger the diameter, the higher the investment. It is necessary to optimize the pipe size and reduce the construction and operation costs on the premise of meeting the use requirements.
1. Basic formula
Common flow-velocity formula for irrigation system to calculate pipe diameter:
Q=A×VQ = A \times VQ=A×V
Where:
Q = flow (m³/s)
A = pipe cross-sectional area (m²), A = π × (D/2)²
V = flow velocity (m/s)
2. Recommended flow velocity
Pipe Diameter Range | Recommended Flow Velocity (m/s) | Remarks |
D < 100mm | 0.6 - 1.5 | Low velocity for small diameters to avoid water hammer |
100mm ≤ D ≤ 300mm | 1.0 - 2.0 | Moderate velocity for medium diameters |
D > 300mm | 1.2 - 2.5 | Higher velocity allowed for large diameters |
3. Diameter calculation example
Assuming the design flow rate is 50m³/h, convert to m³/s:
Q=503600≈0.0139 m3/sQ = \frac{50}{3600} ≈ 0.0139 \, m³/sQ=360050≈0.0139m3/s
Take the design flow rate V = 1.5 m/s, then the pipe cross-sectional area:
A=QV=0.01391.5≈0.00927 m2A = \frac{Q}{V} = \frac{0.0139}{1.5} ≈ 0.00927 \, m²A=VQ=1.50.0139≈0.00927m2
Calculate the inner diameter D:
D=2×Aπ=2×0.009273.1416≈0.1085 m≈110mmD = 2 \times \sqrt{\frac{A}{\pi}} = 2 \times \sqrt{\frac{0.00927}{3.1416}} ≈ 0.1085 \, m ≈ 110mmD=2×πA=2×3.14160.00927≈0.1085m≈110mm
Therefore, DN110 HDPE pipe is recommended.
1. Common nominal pressure (PN) levels
Nominal Pressure (PN) | Maximum Working Pressure (MPa) | Application Scenario |
PN6 | 0.6 MPa | Gravity flow, low-pressure water conveyance |
PN10 | 1.0 MPa | General farmland irrigation |
PN12.5 | 1.25 MPa | Undulating terrain, medium to long-distance water transport |
PN16 | 1.6 MPa | Large elevation differences or sprinkler systems |
PN20 | 2.0 MPa | High-pressure main water supply pipelines |
2. Pressure verification formula (Hagen-William formula)
Hf=10.67×L×Q1.85C1.85×D4.87H_f = 10.67 \times \frac{L \times Q^{1.85}}{C^{1.85} \times D^{4.87}}Hf=10.67×C1.85×D4.87L×Q1.85
H_f = Head loss along the way (m)
L = Pipeline length (m)
Q = Flow rate (L/s)
C = Hagen-William roughness coefficient (HDPE takes 150)
D = Pipeline inner diameter (mm)
According to the water source pressure, head and terminal equipment requirements, after verifying the head loss, select the appropriate pressure level.
Determine the design flow (based on the irrigation area, irrigation method, etc.).
Select a reasonable flow rate (based on pipe diameter and system type).
Calculate the pipe diameter (to ensure sufficient flow and economic rationality).
Calculate the head loss based on the terrain and pipe length.
Determine the pressure level (to meet safety and operation requirements).
Comprehensively consider cost and installation convenience to optimize the selection.
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HDPE pipes (high-density polyethylene pipes) are widely used in the field of gas transportation. Due to their superior performance and high safety, they have gradually replaced traditional metal pipes. The following is a detailed description of the advantages and safety standards.
1. Excellent corrosion resistance
HDPE pipes have strong corrosion resistance to chemicals such as acids, alkalis, and salts. They are particularly suitable for buried gas pipeline systems, avoiding the risk of metal pipelines being easily rusted and leaked, and extending their service life.
2. Good flexibility and seismic resistance
HDPE pipes have good flexibility and impact resistance, can adapt to geological movements such as ground subsidence and earthquakes, reduce the probability of pipeline breakage and loose interfaces, and ensure the continuity and safety of gas transportation.
3. Reliable connection and no leakage
HDPE gas pipes mostly use hot-melt butt or electric fusion connection technology. The welding part is integrated with the parent material, and the connection strength is higher than the pipe body, ensuring that the pipeline system is leak-free and significantly improving the operation safety.
4. Lightweight and easy to construct
Compared with traditional metal pipes, HDPE pipes are lighter, easier to transport and lay, and can be supplied in coil form, which reduces the number of interfaces, shortens the construction period, and reduces engineering costs.
5. Excellent aging resistance and service life
HDPE gas pipes are added with anti-ultraviolet and anti-aging additives, and have a service life of more than 50 years (under normal temperature and pressure conditions), greatly reducing the frequency and cost of subsequent maintenance.
6. Good fluid transportation performance
The inner wall of HDPE pipes is smooth, with low friction resistance and a larger flow rate under the same caliber, saving energy transportation costs and improving gas transportation efficiency.
1. ISO 4437 standard
Internationally, HDPE gas pipelines mainly follow the ISO 4437 standard, which regulates the materials, performance, test methods and use requirements of polyethylene (PE) pipeline systems for gas transportation, ensuring the safety and reliability of the pipelines.
2. China National Standard GB 15558
In China, HDPE gas pipelines implement "GB 15558.1-2015 Buried Polyethylene (PE) Pipeline System for Gas Part 1: Pipes", which strictly stipulates the raw materials (PE80, PE100), pipeline pressure levels, dimensions, tolerances, and physical properties (resistance to hydrostatic pressure, resistance to slow crack growth, resistance to rapid crack expansion, etc.).
3. ASTM D2513 (American standard)
American HDPE pipes for gas follow the ASTM D2513 standard, covering the classification of pipes, material requirements, physical properties, connection methods and pressure testing, ensuring the safe application of pipelines.
4. Safe operation specifications
Construction standards: HDPE gas pipe construction must follow standardized operations, such as the "Gas Pipeline Engineering Construction and Acceptance Specifications" (GB 50251-2015), to ensure welding quality, laying depth, and protective measures are in place.
Inspection and acceptance: including pressure testing, welding quality testing, flaw detection, etc., to ensure that there is no leakage and no defects before it can be put into use.
Regular inspection and maintenance: According to the gas company and industry specifications, regular pipeline inspections, inspections, and preventive maintenance are carried out to ensure long-term safe operation.
HDPE pipe has become the preferred material for gas transportation with its excellent corrosion resistance, flexibility, leak-free connection method and long life. At the same time, perfect international and domestic safety standards provide a strong guarantee for the safe operation of HDPE gas pipelines. With the continuous development of urban gas pipeline networks, HDPE pipes will play a more important role in the field of gas transportation.
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High-density polyethylene (HDPE) pipes have been widely used in the field of municipal engineering due to their excellent corrosion resistance, flexibility, connection reliability and long service life, especially in water supply and drainage, gas, power sheathing and sewage treatment systems. However, HDPE pipes still need to strictly follow the specifications during installation to ensure the quality of the project and the safety and stability of pipeline operation.
1. Material acceptance: Confirm that the HDPE pipes and fittings used meet the design and national standards, and check whether there are cracks, scratches, deformation and other defects on the surface of the pipe.
2. Construction site inspection: Clean the construction site to ensure that the foundation is flat and there are no sharp stones or hard objects to prevent damage during pipeline laying.
3. Equipment preparation: Prepare corresponding Pipe Welding Machine, hot melt sleeve machine, electric melting machine according to the scale of the project.
1. Correct handling and storage:
Handle with care during handling to avoid severe impact and falling.
Place the pipe on a flat surface during storage to avoid long-term direct sunlight and heavy pressure.
2. Selection of pipe connection method:
Butt-melt: Suitable for the connection of large-diameter straight pipes. The welding surface must be kept clean, and the welding temperature and pressure must meet the standards.
Electrofusion connection: Suitable for connection with limited space or special pipe fittings. The welding surface should be cleaned before connection, and the operation should be strictly carried out in accordance with the parameters provided by the electrofusion pipe fitting manufacturer.
Flange connection: Suitable for connection with metal pipes or equipment interfaces. Sealing gaskets should be used to tighten the bolts evenly.
3. Pipeline laying and backfilling:
Pipeline laying should be straight and stable, and the turning point should be constructed according to the minimum bending radius to prevent damage caused by forced bending.
Backfill soil should be compacted in layers. It is forbidden to directly roll the top of the pipe with large machinery to avoid local pressure causing pipe deformation.
1. Temperature influence:
HDPE materials are greatly affected by temperature. During winter construction, the heating and cooling time should be appropriately extended, and in summer, overheating and deformation should be prevented.
2. Welding quality control:
After each welding, the flatness and uniformity of the weld should be checked, and the welding strength test should be performed if necessary to ensure that the welding is firm and reliable.
3. Prevent foreign matter from entering the pipeline:
During the installation process, the pipeline opening should be temporarily blocked to prevent mud and debris from entering and affecting subsequent use.
Pressure test: After the installation is completed, a water pressure or air pressure test should be carried out according to the specifications to check the sealing and pressure bearing capacity of the pipeline system.
Inspection of the interface between the inspection well and the pipeline: Ensure that the interface between the inspection well and the pipeline is tight and there is no leakage.
Completion data is complete: including construction records, welding records, pressure test records, etc., to provide guarantees for subsequent operation and maintenance.
Regularly check the operation of the pipeline, focusing on the ground settlement area and the interface.
For areas with shallow burial depth and large external force influence, protective measures can be added to extend the service life.
The application of HDPE pipes in municipal engineering not only improves the durability and economy of the pipe network, but every detail in the installation process cannot be ignored. Scientific and standardized construction management is the key to ensuring the long-term safe operation of the HDPE pipe system.
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In the chemical industry, transporting corrosive media such as acids, alkalis, salts and other chemicals is a very challenging task. As the core of the transportation system, the material selection of the pipeline directly affects the safety and economy of operation. Among many materials, high-density polyethylene (HDPE) pipes have become one of the first choices in the chemical industry due to their excellent corrosion resistance, toughness and service life.
1. Excellent corrosion resistance
HDPE pipes have extremely high chemical stability to most inorganic acids, alkalis and salt solutions. It can effectively resist corrosive media such as sulfuric acid, hydrochloric acid, sodium hydroxide, and is widely used in chemical waste liquids, wastewater treatment, industrial water supply and drainage systems.
2. High impact strength and good wear resistance
HDPE pipes have good flexibility and impact resistance, and can maintain excellent performance even in low temperature environments, and are not prone to rupture. At the same time, its inner wall is smooth, the fluid resistance is small, and it is not easy to scale and clog after long-term use.
3. Easy installation and low maintenance cost
HDPE pipes can be connected by hot-melt or electric fusion. The joints are firm and leak-free, suitable for long-distance continuous laying, greatly reducing connection points, and reducing maintenance costs and labor costs.
4. Long service life and high cost performance
Under normal use conditions, the service life of HDPE pipes can reach more than 50 years, and its overall return on investment is much higher than that of traditional metal or cement pipes.
In the chemical industry, according to different conveying media and pressure requirements, the following commonly used HDPE acid and alkali resistant pipe specifications are recommended:
Specification (Outer Diameter × Wall Thickness) | Pressure Rating (PN) | Application Examples |
63mm × 5.8mm | PN10 | Laboratory waste discharge, small-scale chemical systems |
110mm × 10.0mm | PN16 | Main pipelines for acid and alkali transport |
160mm × 14.6mm | PN16 | Circulating water or wastewater systems in chemical plants |
250mm × 22.7mm | PN16 | Pipelines in large chemical industrial parks |
Note: All recommended products are made of PE100 raw material and comply with ISO 4427 and GB/T 13663 standards.
1. Clarify the type and concentration of the conveying medium and select the appropriate pressure level;
2. Confirm the operating temperature of the pipeline. Generally, HDPE pipes are suitable for the range of 0℃ to 60℃;
3. Experienced manufacturers are preferred to ensure the quality of raw materials and welding technology;
4. Use corrosion-resistant HDPE pipe fittings to ensure the overall performance of the system.
In the pursuit of efficient, safe and sustainable modern chemical industry, HDPE acid- and alkali-resistant pipes are gradually replacing traditional pipes with their excellent comprehensive performance and cost advantages, becoming the ideal choice for the new generation of chemical conveying systems. We recommend that purchasers give priority to certified and experienced HDPE pipe manufacturers when selecting to ensure stable, safe and reliable system operation.
Official website: www.phtopindustry.com | www.phpipes.com
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