What are the key requirements for the installation of HDPE pipe systems?

1. Connection process requirements (core link)

One of the advantages of HDPE pipe is that they can achieve completely fused and leak-free connections, but this also imposes strict requirements on the connection process.

1.1 Clean pipe ends: Before connection, the dust, oil, and moisture on the connection surfaces of the pipes and fittings must be thoroughly removed using a clean cloth or special tools to ensure a clean fusion surface.

1.2 Precise cutting and trimming: The pipes must be cut perpendicularly to the axis, with a smooth and burr-free cut. Use a special scraper to remove the oxide layer (usually scrape 1-2mm), ensuring the fusion surface is fresh polyethylene material.

1.3 Correct use of hot-melt equipment:

*Hot plate temperature: The correct hot plate heating temperature must be set according to the pipe size and ambient temperature (usually 210±10℃ for PE100 material).

*Heating time and pressure: Strictly follow the standards (such as ISO 21307 or ASTM F2620) for heating time, heating pressure, and cooling hold time. Insufficient time leads to insufficient fusion, while excessive time may degrade the material.

*Butt joint process: After heating, quickly remove the hot plate and join the two pipe ends at the specified pressure within the prescribed time to form a uniform “flare” (curl).

1.4 Electrofusion connection precautions: For electrofusion fittings, ensure the correct insertion depth of the pipe, a tight fit between the fitting and the pipe outer wall, and that the welding parameters (voltage, time) match the fitting.

1.5 Full cooling: After fusion, the pipe must be held under pressure and cooled without external force for the specified time (usually 1-2 times the welding time). Do not cool with water or move the pipe, as this may cause the joint to crack.

2. Trench and foundation requirements

2.1 Trench excavation: The bottom of the trench should be flat, free of sharp stones, tree roots, and other hard objects to prevent uneven force on the pipe after backfilling.

2.2 Foundation treatment: According to soil conditions, lay an appropriate base layer (such as fine sand, fine soil, or crushed stone layer), typically 100-150mm thick, to provide uniform support for the pipe.

2.3 Trench width: It should be wide enough to allow operators to perform connection work, usually 1.5-2 times the pipe diameter.

3. Pipe laying requirements

3.1 Avoid excessive bending: Although HDPE pipes are flexible, the bending radius must not be less than the minimum allowable bending radius (usually 20-30 times the pipe diameter) to prevent pipe wall wrinkling or damage.

3.2 Prevent scratches and impacts: Handle and lay the pipes gently, use non-metallic lifting tools, and avoid friction or collision with hard objects.

3.3 Temperature influence: HDPE has a high coefficient of thermal expansion. For long straight pipe sections, consider the expansion and contraction caused by temperature changes. If necessary, set up flexible connections or bends to absorb displacement.

3.4 Burial depth requirements: Comply with local regulations, typically buried below the frost line with sufficient cover thickness (generally ≥0.8m) to protect the pipe.

4. Backfilling requirements

4.1 Layered backfilling: Within 300mm from the bottom to the top of the pipe, use fine soil or sand for manual layered backfilling and compaction. Each layer should not exceed 200mm in thickness. Mechanical direct compaction above the pipe is strictly prohibited.

4.2 Backfill material: Must not contain stones larger than 25mm in diameter, frozen soil blocks, or construction waste.

4.3 Symmetrical backfilling: Backfill on both sides should be carried out simultaneously to ensure uniform force on the pipe and prevent displacement.

5. Pressure testing and quality inspection

5.1 Visual inspection: Check that the flares of all fusion joints are uniform, symmetrical, and smooth, without holes, collapses, or misalignment.

5.2 Flare removal inspection: For critical projects or sampling inspections, remove part of the flares as required by the standard to inspect the internal fusion condition.

5.3 Pressure testing: After system installation, a water pressure test (usually 1.5 times the working pressure, with a stabilization time of no less than 1 hour) must be conducted to ensure no leakage. Gas pressure testing is strictly prohibited to prevent explosion risks. The successful installation of HDPE pipe systems hinges on strictly adhering to standards, using qualified equipment, and training professional personnel.

Any oversight, particularly during the fusion and backfilling processes, can lead to system leakage, deformation, or premature failure. Therefore, selecting an experienced construction team and implementing full-process quality control are fundamental guarantees for ensuring the long-term safe operation of HDPE water supply pipelines.

Supplier

Luoyang Datang Energy Tech Co.Ltd is a leading Chinese manufacturer specializing in high-quality plastic pipes and fittings. Equipped with state-of-the-art automated production lines and supported by a team of 200 professionals, we offer an extensive product line comprising over 150 types of plastic pipes and fittings designed for water supply and  drainage systems, gas transmission, and floor heating systems. Our main products include PVC Pipes and Fittings, PE (HDPE) Pipes and Fittings, PPR Pipes and Fittings, and PEX Floor Heating Pipes. 

Should you have any inquiries regarding PPR pipes,Brass Valves and brass fittings, please do not hesitate to contact us!

Tel.:0086-183 3790 0677

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