HDPE Structured-Wall Spiral Pipe (Krah Pipe)

Product Introduction

HDPE spirally-wound structural-wall pipes (Type B) are large-diameter, buried plastic pipes manufactured primarily from high-density polyethylene (HDPE). They utilize a hot-winding process, incorporating a PP single-wall corrugated pipe as a structural support, resulting in a product with a smooth inner surface and a reinforced, profiled outer wall. These pipes are produced in standard 6-meter lengths with internal diameters ranging from DN300 to DN4000. The manufacturing process involves hot-winding, where molten HDPE strips are wound and welded simultaneously with the support pipe; upon cooling and solidification, this creates high-strength fusion joints. Electrofusion socket connections are typically used, ensuring a 100% leak-free system. Available series include: PR/OP (primarily for drainage), SQ (for manholes/containers), and VW (specifically for pipe fittings).

Product Features

1. High Ring Stiffness: Available in classes such as SN8, SN12.5, and SN16, offering excellent resistance to external pressure and soil settlement—ideal for deep-burial applications.

2. Corrosion and Aging Resistance: Resistant to acids and alkalis with no risk of electrochemical corrosion; requires no additional anti-corrosion treatment, with a design service life of ≥50 years.

3. Superior Hydraulic Performance: The low roughness of the inner wall allows for a flow capacity 20%–30% higher than that of concrete pipes of the same diameter.

4. Lightweight and Easy to Install: Significantly lighter than concrete pipes, requiring less trench excavation, which shortens construction timelines and reduces costs.

5. Eco-friendly and Recyclable: Made from HDPE, an environmentally friendly material that can be recycled and reused. Executive Standard

GB/T 19472.2-2017

Common Internal Diameter Specifications

HDPE "Krah" pipes (structured-wall HDPE pipes) are typically designated by their nominal internal diameter. A wide range of standard sizes is available, including: DN200, DN300, DN400, DN500, DN600, DN800, DN1000, DN1200, DN1500, DN1800, DN2000, DN2400, and DN3000.

Scope of Application

HDPE "Krah" pipes are primarily designed for buried gravity-flow drainage and sewage projects. Common applications include:

Municipal Drainage Projects

Urban rainwater and sewage pipeline systems.

Rainwater and Sewage Separation Projects

Pipeline network separation for both the renovation of older urban areas and new urban developments.

"Sponge City" Projects

Rainwater collection, storage/detention, and discharge systems.

Roadway Drainage

Drainage pipelines for municipal roads, industrial/business park roads, and highways.

Residential Drainage

Buried outdoor rainwater and sewage pipelines for residential communities.

Industrial Drainage and Sewage

Pipeline networks for general industrial wastewater and site drainage.

Agricultural Water Conservancy, Irrigation, and Drainage

Projects for farmland drainage, flood control, and irrigation water conveyance.

Large-Scale Trunk Drainage Pipelines

Interceptor sewers, main drainage trunks, and large-diameter rainwater trunk lines.

Infrastructure for Ports, Airports, and Stations

Rainwater and sewage discharge systems for these facilities.