At approximately 6:00 p.m. on January 9, 2017, an underground natural gas pipeline was damaged at a construction site for Zhengzhou Metro Line 5 near the intersection of Wenhua Road and Huanghe Road in Zhengzhou, China.

The pipeline damage resulted in a natural gas leak and fire, affecting more than 4,000 residential users and over ten commercial and industrial users along Huanghe Road. 

Gas Pipeline Damaged During Metro Construction

According to the original incident report, the accident occurred during construction work at the Wenhua Road Station section of Zhengzhou Metro Line 5.

A steel gas transmission pipeline was reportedly damaged during excavation work, resulting in the gas leak and subsequent fire.  

The incident illustrates one of the risks associated with construction activities near underground pipeline infrastructure.

Exact Cause Required Further Investigation

The original report also recorded a different account from a person at the site who identified himself as a member of the construction team.

According to this account, construction had been carried out in accordance with the design drawings, and the construction location was more than one meter away from the underground natural gas pipeline.

The report therefore stated that the specific cause of the incident still required further investigation.  

Third-Party Excavation Risk to Underground Pipelines

Construction and excavation activities near buried pipelines can present significant risks to pipeline integrity.

Excavators, drilling equipment and other construction machinery may damage underground pipelines when pipeline locations are inaccurate, construction boundaries change, or excavation activities approach protected pipeline corridors.

For pipeline operators, detecting potentially damaging activity before physical contact with the pipeline occurs can provide valuable time for investigation and intervention.

Fiber Optic Pipeline Anti-Excavation Monitoring

Pipeline fiber optic vibration detection and anti-excavation systems  can provide continuous monitoring along pipeline routes and detect vibration events associated with activities such as manual or mechanical excavation.

Distributed fiber optic vibration sensing uses optical fiber deployed along the pipeline route as a sensing medium.

When potentially damaging activity occurs near the monitored pipeline, the system can identify the event, determine its approximate location and generate an alarm for operators.

This type of monitoring can provide an additional layer of protection for long-distance pipelines and other buried infrastructure exposed to third-party construction risks.

Pipeline Safety Requires Multiple Layers of Protection

Fiber optic anti-excavation monitoring should form part of a broader pipeline integrity and safety strategy.

Pipeline route management, accurate underground utility records, construction coordination, warning signs, patrols, inspection, operating procedures and emergency response all remain important components of pipeline protection.

Continuous monitoring can complement these measures by providing operators with additional visibility into potentially damaging activities occurring along the pipeline route.