Tarry Town Sleepy Hollow

Fixing a Gas Main, 21st Century Style

Crews are using robotics to repair a leaking gas main on Franklin Street.

Editor: Sean Roach

The joint used to maintain a seal and allow entry of the CISBOT into a Con Ed main

Last week, a gas leak was reported on Franklin Street between Windle Park and Miller Avenue.

Con Edison crews determined the general location of the leak and began to excavate the gas main below the street in order to conduct repairs.

Since then, motorists have been annoyed at the work being done, largely because it has blocked off one of the main arterial roads to the Tarrytown Train Station used by commuters.

However, what many people don’t realize is the precision and skill being used to fix this particular gas main, all without disrupting gas service to local residents.

Below Franklin Street, a robot is methodically working through the main to find aged seals that are the cause of the leak, and others that are in need of repair.

Shawn Patrick is a robotics operator with ULC Robotics based out of Bay Shore. One of ULC’s biggest customers is Con Edison, which uses its services for minimally invasive repairs to pipes.

Patrick sits behind the control console in his truck looking at a screen that is similar to something you would see during laparoscopic surgery. Patrick is controlling a CISBOT – a robot that is propelled into an active gas main, to inject sealants in faulty joints. The robot looks something like an arm, complete with a camera and a small drill that has the ability to inject substances. The back end is connected to a cord that leads back into the ULC Robotics control station.

The excavation site on Franklin Street

For the past two days, ULC Robotics has worked to repair the pipe 100 feet to the east and 100 feet to the west, through one entry port on the gas main.

“We go as far as the robot can go,” said Patrick.

The robot drills small holes near the iron pipe’s joints and injects an anaerobic sealant. Within 24 hours, the sealant turns into a hard rubber gasket that will last about 50 years.

Some people might think that having active robotics inside of a live gas main would be dangerous, but because the seal on the pipe remains intact through a modified access point (see photos), there is no oxygen inside the pipe to help spark an explosion.

While commuters might be annoyed by the delays, using robotics to fix faulty joints allows for crews to repair 200 feet of gas main with only one dig site. Without the use of robotics, Con Edison crews would have to excavate every 12 feet to gain access each joint along the gas main.

Robotic work is expected to be completed by Friday afternoon. The excavation site will then be covered over the weekend before being fully repaired by Con Edison early next week.

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