Heating pipelines are buried underground, making it difficult to promptly detect issues-such as aging insulation, cracked joint seals, or minor leaks-through manual foot patrols. Walking along dozens of kilometers of pipeline is not only inefficient, but many hazards often go unnoticed until steam rises from the road surface or users file complaints. A single drone flight equipped with infrared thermal imaging converts the underground pipeline's temperature distribution into visual images, making anomalies immediately apparent.
In a properly functioning pipeline, temperature distribution remains uniform where insulation is intact. If a section of insulation is damaged or compromised by water ingress, heat concentrates and radiates outward, appearing as a high-temperature patch on the thermal image.
If a leak has occurred, the high-temperature water or steam heats the surrounding soil, creating a distinct "hot spot" on the thermal image. Drones fly along the pipeline, marking anomalous locations on the thermal images, allowing ground crews to proceed directly to those spots for verification.
Hohhot Futai Heating used drones to survey nearly 50 kilometers of its network, identifying several temperature anomalies and confirming hidden leak points through excavation. Xintai Heating's drone inspections can detect over twenty types of hazards, including insulation damage, interference from third-party construction, and valve irregularities. The Suizhou High-tech Zone has deployed an intelligent drone hangar system capable of automatic, scheduled inspection flights. The "Liao-Re-Ru-Ji" (Liaocheng-to-Jinan) long-distance transmission project spans over 130 kilometers; while a manual inspection would take a week, a drone can cover the entire route in just six hours.
The value of infrared thermal imaging extends beyond merely locating leaks. Areas with damaged insulation or moisture ingress-even before a leak occurs-produce anomalous signals on thermal images. By archiving data from each flight and comparing it with previous results, operators can track which sections are gradually deteriorating. Some heating companies also use drones to monitor for excavators working along the pipeline route, thereby preventing third-party damage before it happens.
While drone flights yield thermal images and data, the key lies in how this information is utilized. Some heating companies report that processing and analyzing the resulting volume of thermal images requires specialized personnel and software, leaving room for efficiency improvements. Additionally, if alarm thresholds are set too sensitively, false positives increase, resulting in a significant workload for on-site verification. In addition, smog, rain, and snow can affect the accuracy of thermal imaging, while cloud cover can lead to data distortion. Currently, many projects employ a combined approach involving drones supplemented by manual verification on the ground.