High barrier HDPE‑EVOH double wall pipe is engineered for underground fuel delivery systems at petrol stations. Manufactured by multi‑layer co‑extrusion technology, it embeds EVOH barrier material inside the inner pipe wall to achieve ultra‑low hydrocarbon permeation. The unique double‑wall pipe‑in‑pipe structure provides secondary containment function. The annular gap between inner pipe and outer pipe can be connected to leak‑detection instruments for real‑time interstitial monitoring. Once the inner transport pipe is damaged, the outer protective pipe can contain leaked fuel, preventing petroleum products from seeping into soil and underground water.
Constructed from high‑density polyethylene, the pipe features excellent chemical resistance against gasoline, diesel, ethanol‑blended fuels and biodiesel. It avoids electrochemical corrosion which commonly troubles traditional steel pipelines for buried installation. Optional conductive modification helps dissipate static electricity generated by fast‑flowing fuel inside pipelines, effectively reducing static‑induced risks at fueling facilities.
This double wall composite pipe adopts electrofusion jointing with matched PE electrofusion fittings. Electrofusion welding creates integrated molecular connection between pipe and fittings, ensuring joint tightness and minimizing leakage risks at connection points. Products are supplied in both coil and straight pipe formats. Flexible coil pipe reduces on‑site joint quantity, speeds up laying work and lowers overall construction expenditure. It is well‑suited for new gas station construction, as well as renovation and expansion of existing fuel stations.
The pipe system maintains stable mechanical performance under soil pressure and surface traffic load. Its burst pressure is far above normal operating pressure to guarantee long‑term buried service. Supporting fittings such as elbows, tees, reducers and end caps can be provided to assemble complete underground fuel transfer networks, covering suction pipelines, fill pipelines and VRU vapor recovery lines.
Benefiting from the EVOH high‑barrier layer, fuel vapor permeation loss is greatly restrained. It satisfies environmental regulations for underground fuel storage and transportation. Various nominal diameters are available to match different flow requirements. As a low‑maintenance underground fuel pipeline solution, it delivers reliable safety performance for modern petrol station projects.