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Views: 0 Author: Site Editor Publish Time: 2025-10-22 Origin: Site
PPH pipes are widely used in chemical, municipal, and construction industries due to their advantages such as corrosion resistance, high-temperature tolerance, and long service life. However, improper installation can lead to issues like leaks and pipe bursts. This article systematically introduces the installation methods, key construction points, and preventive measures for common risks to help engineers complete projects efficiently.
Material Inspection
Check the specifications and models of pipes and fittings to ensure they are free from damage, deformation, or contamination.
Verify that the materials meet design requirements (e.g., pressure rating, chemical resistance) and inspect factory certifications.
Tool and Site Preparation
Specialized tools: Hydraulic heat fusion welder, pipe cutter, acetone, clean cloth.
Site requirements: Clear trenches or elevated areas of debris and standing water; set up a welding shelter to protect against wind and rain.
Use a dedicated pipe cutter to ensure the cut is smooth and free of burrs. Rotate the blade gradually during cutting to avoid angled cuts.
PPH pipes primarily use hot melt connection (for small diameters) and electrofusion connection (for large diameters). Key steps are summarized in the table below:
| Step | Hot Melt Connection Key Points | Electrofusion Connection Key Points |
|---|---|---|
| Preheating/Parameter Setting | Heat plate temperature to 195–205°C (some require 220–230°C); adjust pressure to specified values. | Set welding current and time according to fitting specifications. |
| Alignment & Cleaning | Flatten pipe ends and clean with acetone to remove oil, dust, and contaminants. | Ensure pipes and fittings fit tightly with no gaps. |
| Heating & Fusion | Heat until the bead reaches 1mm, then quickly join and maintain pressure during cooling. | Observe indicator lights during welding; avoid moving pipes. |
| Cooling | Allow to cool naturally for at least 1 hour; avoid disturbing the pipe during this time. | Same cooling time; prevent joint deformation. |
Note:
For hot melt connections, strictly control temperature and time. Overheating degrades the material, while insufficient heat weakens the bond.
For flange connections, ensure proper alignment (axial deviation ≤2mm) and tighten bolts diagonally in two stages.
Support Setup
Set support spacing according to pipe diameter (see table below) to prevent sagging or deformation:
| Pipe Type | Diameter Range | Max Spacing (Horizontal) | Vertical Spacing |
|------------|----------------------|--------------------------|---------------------|
| Horizontal | ≤40mm | 1.0m | - |
| Horizontal | 63–125mm | 1.2m | - |
| Horizontal | 160mm | 1.5m | - |
| Vertical | All sizes | - | ≤1.2m |
Supports should accommodate thermal expansion of pipes; use sliding pipe supports (e.g., angle steel, split steel pipes).
Installation Environment Requirements
Temperature limits: Avoid construction when ambient temperature is below 0°C. If below 5°C, take heating measures.
Pipes should not be directly embedded in concrete; use trenches or protective sleeves instead.
Hydrostatic Test Steps
Increase pressure to 1.5 times the design pressure and maintain for 15 minutes to 24 hours.
A pressure drop of ≤0.05MPa is considered acceptable.
Filling and venting: Slowly fill with water to remove air.
Stabilization test:
Post-Test Procedures
Cleaning and disinfection: Flush pipes after testing; disinfect potable water pipes.
Product protection: Mark pipe routes to prevent impact or nailing.
| Issue | Cause | Preventive Measures |
|---|---|---|
| Joint Leaks | Uneven heating/improper cleaning | Regularly calibrate welder temperature; thoroughly clean welding surfaces with acetone. |
| Pipe Deformation | Excessive support spacing or improper fixation | Strictly follow support spacing standards; install supports every 1.2m for vertical pipes. |
| Low-Temperature Brittleness | Lack of winter protection | Halt construction below 0°C; drain pipes for overwintering. |
Welders must be trained and certified; keep fire extinguishers on-site.
For elevated work, inspect lifting equipment load capacity to prevent pipe falls.
PPH pipes can have a service life of up to 50 years, but their reliability heavily depends on construction quality. Strict adherence to material inspection, standardized welding, proper support, and thorough pressure testing are crucial for ensuring long-term system stability. It is recommended to conduct technical reviews with manufacturers before construction and hire professional teams for operations.
