HDPE pipe and fitting,PVC pipe and fitting

High-density polyethylene (HDPE) pipes are widely used in water supply, drainage, gas transmission, and industrial pipelines due to their excellent corrosion resistance, flexibility, long service life, and environmental friendliness. To ensure the quality of HDPE pipe construction, strict compliance with relevant specifications is essential. This article details the construction standards for HDPE pipes, covering key stages such as material inspection, storage, welding, installation, and backfilling.

Material Inspection and Storage

1. Material Inspection

Check the factory certificates, test reports, and specifications of pipes and fittings to ensure compliance with design requirements.

Visual inspection: Pipes must be free of cracks, dents, bubbles, or impurities, with uniform color and clear markings.

Dimensional inspection: Pipe diameter and wall thickness must meet national standards (e.g., GB/T 13663, ISO 4427).

 

2. Storage Requirements

HDPE pipes should be stored on a flat, ventilated site, avoiding direct sunlight and high temperatures (recommended temperature ≤ 40°C).

Stacking height should not exceed 1.5 meters to prevent deformation.

Pipes must be kept away from sharp objects to avoid scratches.

 

Pipe Welding Specifications

HDPE pipes are primarily joined using butt fusion welding or electrofusion welding, with strict adherence to welding procedures.

1. Butt Fusion Welding

Preparation

Verify welding machine temperature (typically 210±10°C) and pressure settings.

Clean pipe ends to remove oil, dirt, or debris.

Use clamps to align pipes properly.

Welding Process

Heating phase: Heat pipe ends until molten (duration depends on pipe diameter and wall thickness).

Transition phase: Quickly remove the heating plate to prevent oxidation.

Joining phase: Apply pressure to fuse the ends and maintain pressure during cooling.

 

Quality Inspection

Check for uniform weld beads with no cracks or weak joints.

Bead height should meet standards (typically 10%~20% of wall thickness).

2. Electrofusion Welding

Preparation

Clean pipe and fitting surfaces, removing oxidation layers.

Ensure electrofusion fittings match pipe specifications.

 

Welding Process

Insert pipe into the electrofusion coupler until fully seated.

Apply electricity according to the manufacturer’s voltage and time parameters.

Do not move the pipe during cooling.

 

Quality Inspection

Check indicator pins on fittings to confirm proper fusion.

 

Pipe Installation Specifications

1. Trench Excavation

Trench width should accommodate pipe installation and backfilling (minimum ≥ pipe outer diameter + 300mm).

Trench bottom must be level and free of sharp rocks; soft soil requires compaction or a sand bedding layer.

2. Pipe Laying

Use manual or mechanical methods to lower pipes, avoiding throwing or dragging.

Minimum bending radius ≥ 25 times pipe diameter to prevent deformation.

Install protective sleeves when crossing roads or structures.

 

Backfilling and Compaction

Initial backfill: Use fine sand or soft soil (free of rocks) up to 300mm above the pipe, compacted in layers (≤ 200mm per layer).

Final backfill: Compact in layers as per design requirements; avoid direct heavy machinery pressure on pipes.

 

Pressure Testing and Inspection

Hydrostatic test: Gradually increase pressure to 1.5 times working pressure, hold for 30 minutes; pass if pressure drop ≤ 5%.

Leak test (gas pipelines): Apply soap solution to check for leaks at joints.

 

Safety Precautions

Welders must wear protective gloves and goggles.

Mark construction zones with warning signs to prevent pipe damage.

Official website: www.phtopindustry.com | www.phpipes.com
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