China Completes First Full-Scale High-Pressure Pure Hydrogen Pipeline Tests

China has completed its first full-scale high-pressure pure hydrogen pipeline jet fire test series, marking a major technical breakthrough in hydrogen safety engineering. On 7 December, China National Pipeline Group (CNPG), together with the China Academy of Work Safety Science, successfully carried out the tests at CNPG's Pipeline Rupture Control Test Site in Hami, Xinjiang — filling a key technical gap in the field.

The trials were designed to obtain critical data on flame behaviour and thermal radiation impact following hydrogen leaks, establishing thresholds for thermal radiation injuries and defining safe clearance distances under ignition conditions. The test platform consisted of a hydrogen main pipeline, jet fire branch pipes, ignition systems, and data acquisition units. With a storage capacity of 12,000 cubic metres, the main pipeline enabled continuous monitoring of leakage and jet fire dynamics across multiple test conditions.

Launched on 11 November and concluded after nearly one month, the programme featured 33 test scenarios incorporating four leakage aperture sizes (5mm, 10mm, 25mm, 50mm), three jet orientations (horizontal, 45° inclined, vertical), and three pressure levels (3.4MPa, 6.3MPa, 10MPa). The jet fire branch pipe was mounted at the 12 o'clock position on the pipeline's upper surface to replicate real-world hydrogen leakage patterns. Ignition was achieved through coordinated use of a professional flame-projecting drone and a remote high-voltage electronic device, enabling comprehensive data collection — another first for China. During the trials, teams deployed precision instruments including radiometers, pressure and temperature sensors, thermocouples, and high-speed cameras to capture real-time flame characteristics and thermal hazard zones.

Preliminary analysis shows that the data collected is complete and valid, providing a scientific basis for defining safety distances for pure hydrogen pipelines. CNPG will further refine its thermal radiation assessment model for hydrogen pipeline jet fires using these experimental results, contributing to China's hydrogen pipeline safety standards and supporting the secure, large-scale transport of hydrogen in line with national dual-carbon goals.

The CNPG Pipeline Rupture Control Test Site — where the hydrogen jet fire trials were conducted — is the world's third and Asia's only full-scale pipeline burst testing platform. It is also China's sole facility capable of conducting full-scale burst tests on high-grade steel, large-diameter, and multi-medium pipelines. The site has previously completed five full-scale gas burst tests on 1219/1422 mm pipelines using X80/X90 steel at 12/13.3 MPa, three cryogenic crack initiation and arrest tests, and three natural gas pipeline leakage and jet fire tests. These efforts provide essential evidence and strong technical support for long-distance pipeline construction and multi-medium pipeline standardisation.