Polyethylene (PE) water supply pipes are a new generation of water transmission lines that, thanks to their unique properties, have become a suitable replacement for metal, concrete, and PVC pipes in urban, rural, and agricultural water-supply networks. High flexibility, outstanding chemical and mechanical resistance, low weight, and reliable weldability have led to their widespread use in infrastructure and industrial projects.
History and evolution of polyethylene materials in water-supply systems
Research on polyethylene began in the 1950s to produce lightweight, durable pipes. The first generation (PE32) was suitable only for low pressures; however, with the development of HDPE resins in the 1970s and 1980s, PE80 and then PE100 classes were introduced. This technological leap increased allowable stress, reduced wall thickness, and consequently decreased the weight and final cost of pipeline systems. Today, PE100-RC materials, with resistance to rapid crack growth (RCG), even enable trenchless installation and pipe laying without excavation.
Types of polyethylene water pipes and standard codes
International standards such as ISO 4427, DIN 8074, and INSO 14427 classify polyethylene water-supply pipes based on the Standard Dimension Ratio (SDR). The smaller the SDR number, the thicker the wall and the higher the operating pressure.
| Material rating (MRS) | Nominal pressure class (PN) | SDR | Wall thickness (mm) for 110 mm OD | Max operating pressure for water at 20 °C (bar) |
|---|---|---|---|---|
| PE80 | PN 10 | 17 | 6.6 | 10 |
| PE100 | PN 12.5 | 13.6 | 8.1 | 12.5 |
| PE100 | PN 16 | 11 | 10.0 | 16 |
| PE100-RC | PN 20 | 9 | 12.3 | 20 |
Note: For long transmission lines, head loss and temperatures up to 40 °C must be considered; above 40 °C a pressure derating factor applies.
Advantages of polyethylene pipe over other materials
- High flexibility: Minimum bend radius up to 20× the outside diameter allows routing through winding corridors.
- Excellent chemical resistance: Resistant to most acids, bases, and aggressive soils; therefore safe for sulfate-rich or acidic grounds.
- Leak-free joints: Butt-fusion and electrofusion technologies create homogeneous joints ensuring 100% sealing.
- Low weight: Lower mass means cheaper transport and faster installation with fewer personnel.
- Service life over 50 years: Accelerated hydrostatic tests show PE100 pipes can operate for half a century under design conditions without performance loss.
- Low friction losses: Surface roughness (k ≈ 0.007 mm) reduces pumping energy and operating costs.
- Impact and earthquake resilience: Elasticity and integral joints keep the system stable against ground vibrations.
Manufacturing process and quality control
Granular HDPE resin, after drying, enters the extruder and, through melting and homogeneous mixing, is conveyed by the screw to the die head. After the pipe is formed in a vacuum calibrator, thermal shock is controlled in a cold-water bath to reduce residual stresses. An inline laser gauge continuously monitors OD and wall thickness. Before issuing inspection certificates, 160-hour hydrostatic tests, Charpy impact tests, and slow crack growth (SCG) tests are performed. The pipe marking includes manufacturer name, date, material, diameter, SDR, and shift number.
Design notes and pipe size selection
First, determine the design flow based on per-capita consumption and a peak factor. Then, using Hazen–Williams or Darcy–Weisbach, select the nominal diameter so that velocity remains between 0.6–2 m/s. For looped networks or long-distance pumping, calculating total head loss is essential to optimize pump power.
| Outside diameter (mm) | Effective area (cm²) | Flow at 1 m/s (L/s) | Standard coil length (m) |
|---|---|---|---|
| 40 | 11.0 | 11 | 400 |
| 63 | 27.8 | 28 | 300 |
| 90 | 57.0 | 57 | 200 |
| 160 | 201 | 201 | 100 |
| 250 | 491 | 491 | 12 m straight length |
Jointing and installation methods
- Butt fusion: After facing and heating both ends to 220–230 °C, they are pressed together under controlled pressure. Uniform cooling forms a strong, homogeneous joint.
- Electrofusion: Couplers containing copper coils melt the pipe sections with electric current to form a seamless ring; ideal for repairs and confined spaces.
- Compression fittings: Used in small diameters and temporary or agricultural systems; fast to install and needs no special tools.
Installation guidelines
- The bedding must be free of sharp stones; use a sand layer at least 10 cm thick.
- Minimum cover for buried urban lines is 80 cm, and 120 cm under road crossings is recommended.
- For above-ground lines, a black compound with 2–2.5% carbon black in the resin protects against UV.
Operation and maintenance notes
Periodic inspection of joints, control of pump surge pressures, and air release on long lines are key actions to ensure network longevity. In case of a local crack, cutting out the damaged section and using an electrofusion coupler provides a fast, reliable repair. Avoid hot cutting with direct flame, as it causes thermal aging of the resin and reduces local strength.
Applications in urban, rural, industrial, and agricultural projects
- Urban drinking-water distribution: Reduction of leakage and non-revenue water (NRW).
- Rural transmission lines: Coiling up to 160 mm reduces the number of joints and shortens installation time.
- Pressurized irrigation systems: Low weight and high flexibility allow easy handling on farms.
- Food and pharmaceutical industries: Inert to taste and odor and resistant to alkaline detergents.
- Coastal desalination projects: Tolerant to saline corrosive environments and suitable for marine outfalls.
Environmental impacts and recycling
Polyethylene is 100% recyclable and, at end of life, can be shredded and used as feedstock for non-pressure products. Compared with metal pipes, its production consumes less energy and emits fewer greenhouse gases. During operation, low leakage and low friction translate into savings in water and energy resources.
Purchase from Tamam Baha
Tamam Baha Trading Group, as a trusted supplier of polyethylene resins and water-supply pipes in Iran, offers a diverse range of PE80 and PE100 products with recognized national and international certifications. With pre-purchase technical advice, on-site welding, and pressure-testing services, the group streamlines water-supply project execution for contractors and owners—serving clients in Iran and across the Middle East.
