New Method For Urban Pipeline Inspection

With the continuous development of the economy, urban gas pipeline construction, as one of the most important projects in infrastructure construction, plays a crucial role in the entire economic construction and development. By 2020, the scheduled mileage of Chinas natural gas pipelines has exceeded 100,000 kilometers. Due to the huge complexity of the underground pipeline system, as well as the aging problem, third-party damage and corrosion, there will be some leakages in the urban gas pipelines that may cause leakage accidents. And the occurring of the accident will result in serious consequences such as personal injuries, waste of resources, environmental pollution and economic losses. Therefore, how to quickly and effectively capture pipeline leakages plays a vital role in reducing or preventing leakage accidents.  



Pic: The underground gas pipelines


At present, the main work of the daily pipeline inspection is to check whether there is any damage to the gas pipelines caused by geological disasters or third-party construction. The inspections are mainly conducted by driving or walking. The crew checks whether there is pipeline damage by judging from their eyes, and then conducts the preliminary inspection with hand-held devices after discovering the suspicious leaking spot.


When the pipeline leakages are caused by aging and corrosion, there are no obvious signs that human eyes can discover on the surface. The integration of Sniffer4D multi-gas detection system and Mavic2 can accurately detect the concentrations of various gases (such as CH4, VOCs, H2S, CO, etc.) during the inspection process, helping the crew judge whether there are pipeline leakages and locate the suspicious leaking spot according to the gas concentration distributions map.



Pic: Sniffer4D+DJI Mavic2


Recently, based on the integration of Sniffer4D and Mavic2, the UAV Inspection & Monitoring Center of Shenzhen Gas, Pingshan Branch carried out a simulated detecting experiment on urban gas pipeline leakages.



Pic: The experimental team of Shenzhen Gas, Pingshan Branch discussing the experimental plan


Through on-site investigation, the experimental team chose the following experimental sites:

①The pavement above the underground gas pipelines;

②The river above the underground gas pipelines.


The crew released natural gas at a pipeline spot on site ① to simulate the gas leakage, then they operated Mavic2 to lift off with Sniffer4D multi-gas detection system and to scan the gas around the scene. During the scanning process, the analytical software Sniffer4D Mapper displayed the real-time gas concentrations and generated a visualized grid map. The results showed that when the drone flew above the simulated leaking spot, the gas concentrations reached the maximum value, indicating that the integration of Sniffer4D and Mavic2 succeeded in capturing the simulated leaking spot.




Pic: Sniffer4D+Mavic2 carried out the simulated experiment on pipeline inspection and generated the real-time grid map of the gas concentration distributions (The green grids indicated lower gas concentrations, and the red grids indicated the high gas concentrations).


Based on further investigation upon pipeline scenarios, the crew believes that the integration of Sniffer4D multi-gas detection system and Mavic2 can help reduce the blind spots for detection and boost their efficiency.


1. Flexible low-altitude scanning and monitoring: Mavic2-mounted Sniffer4D can collect gas information from multi-dimensions in a crowded environment. Compared to the medium and large industrial UAVs, the down-wash airflow generated by the propellers of Mavic2 is much smaller and the target gas is uneasy to be blown away. The integration allows Sniffer4D to be more accurate and more sensitive to locate the leaking spot.


2. Overcoming the terrain obstacles: Mavic2-mounted Sniffer4D can greatly reduce the influence from terrain factors, it can be applied to boost the efficiency of detections under the tree canopy or the bridge, above water or over the slope, etc. Meanwhile, some gases whose detection method is laser reflection have strict requirements on the reflective surface, which makes it difficult to detect on the water surface, but Sniffer4D has no such demand.



Pic: Sniffer4D+Mavic2 detected the water surface with underground pipelines in the simulated experiment.


3. Remote data transmission to avoid risks: Mavic2-mounted Sniffer4D is equipped with remote data transmission, which allows the crew to operate it and scan the gas within 6km away from the detection spot. The crew can stay away from the leaking spot and make sure of their personal safety.


4. Real-time visualized data analysis: The detected gas information from Sniffer4D can be visualized by the analytical software Sniffer4D Mapper. And by generating the real-time gas concentration distributions map, the crew can easily see the concentrations and distributions of the gas pollution and make the corresponding decisions in time.



Pic: Sniffer4D Mapper generated real-time gas concentration distributions map


This experiment has fully shown the potential of the Mavic2-mounted Sniffer4D multi-gas detection system in the urban pipeline inspections. Soarability will keep exploring more applicable scenarios for Sniffer4D to help boost the working efficiency and reduce the risk for users from various industries.