Project background

Jixian County sits in the mountainous northern part of Tianjin, about 110 km from downtown. Its rural villages historically relied on LPG cylinders for cooking and heating. In 2025, the local gas company launched a county-wide pipeline network project to bring natural gas directly to more than 30,000 households across 12 townships.

The pipeline runs about 86 km in total, combining medium-pressure distribution mains (DN200–DN300) and low-pressure service lines (DN50–DN150). The terrain is mixed: flat farmland, shallow river crossings, and sections running through hillside soil with higher resistivity and seasonal water table fluctuation.

The challenge

The project owner had two hard requirements:

1. The pipe had to last at least 30 years without replacement. Rural gas pipelines are buried under farm roads and hillside tracks; digging them up later would disrupt villages and farmland for months.
2. The external coating had to survive both normal soil and the more aggressive wet ground near river crossings, where stray current and moisture would accelerate corrosion on ordinary galvanized pipe.

The previous supplier had proposed standard galvanized steel pipe with a cheaper upfront price. But the design engineers were concerned about long-term corrosion and rejected that option after reviewing failure data on older rural gas lines in northern China.

Why they chose Kaiyide

The project team contacted three Chinese pipe manufacturers for sample testing. After reviewing test reports and a live video factory tour, they chose our 3PE anti-corrosion pipe for the medium-pressure mains and our plastic-coated (EP) pipe for the low-pressure service lines.

Key reasons they gave us:

- Our 3PE pipe is manufactured to GB/T 23257 and DIN 30670, with Type Test approval from the China Special Equipment Inspection and Research Institute. The certification scope exactly matched their pressure rating requirement.
- Every batch came with documented coating thickness, adhesion and impact test reports, plus hydraulic pressure testing at 5.0 MPa with zero leakage.
- We could supply the full size range they needed — from DN50 service pipe up to DN300 main pipe — from one factory, which simplified logistics and inspection.
- Our Tianjin plant was only a 2.5-hour drive from the site, which made emergency restock and technical support during installation much faster than a southern supplier.

What we supplied

For the Jixian project we delivered:

- 3PE external coated seamless and longitudinal-welded steel pipe, DN200 and DN300, for the medium-pressure transmission mains.
- Internal/external plastic-coated (EP) steel pipe, DN50–DN150, for the low-pressure village service lines.
- Matching fittings: bends, tees and flange adapters, coated with the same system to avoid weak points at joints.

Total order quantity was delivered across three batches over six weeks, packed in 40-foot containers and directly trucked to the site staging yard. Our technical engineer visited the site twice during installation to review backfill practice, joint coating and pressure testing.

Installation notes

The site team followed standard 3PE installation practice:

- Trench bottom was cleared of sharp stones before pipe lowering.
- Field weld joints were coated with heat-shrink sleeves matched to the 3PE system.
- Backfill used fine soil around the pipe body, with larger stones placed only in the upper layer.
- Each section was hydro-tested at the design pressure before being buried.

This attention to detail during installation is just as important as the coating itself. Even the best 3PE pipe will fail quickly if it is dropped onto sharp rocks or backfilled with construction debris.

Result

The first phase of the Jixian network was put into service in late 2025. Villages along the 86 km route are now connected to pipeline natural gas instead of LPG cylinders. The project owner has already placed a follow-on order for the next phase covering two more townships.

For Kaiyide, this project is representative of the kind of work we do best: medium-sized municipal gas and water schemes that need real manufacturing quality, documented test reports, and a supplier that can show up on site when needed. It is also why we continue to invest in our coating line and in-house testing equipment — projects like this one rely on it.

What this means for overseas buyers

If you are a gas distributor, EPC contractor or municipal buyer outside China, the same specification we supplied to Jixian is available for export:

- 3PE coated pipe, DN50–DN1800, to GB/T 23257 or DIN 30670.
- Plastic-coated pipe for water, gas and fire service.
- Third-party inspection reports from CCS, SGS or equivalent labs with every shipment.
- Live video factory tour before order, and loading photographs before container departure.

Send us your pipeline diameter, pressure rating, soil condition and quantity, and we will reply within 24 hours with a quotation and sample test reports.