ULC Deploys New 12” CISBOT to Address Leak-Prone Gas Main
Project Overview
With increasing construction costs for traditional leak repair and replacement of medium diameter cast iron gas distribution mains, ULC Technologies looked to expand CISBOT’ capabilities for internal rehabilitation of 12” cast iron joints to provide more cost-effective options to manage leakage.
When faced with multiple joint leaks on a 12” cast iron gas distribution main located under a busy road and 6” of concrete slab, a prominent northeast gas utility was facing high costs of excavation for traditional leak repair and extensive road closure times.
Through just one small excavation in the road, the CISBOT robot was able to enter the live 12” cast iron gas main and travel underground to seal 59 joints over a 15-workday period. The internal joint remediation process worked to extend the life of the gas main with minimal disruption to the community.
Location: Lowell, MA
Pipe Diameter: 12″
Joints Sealed: 59
Project Duration: 15 days
Results:
- Successful advancement in CISBOT capabilities
- 100% of identified leaking joints sealed
- No disruption to customers’ gas services
- Overall major project cost savings
CHALLENGES
Traditional leak repair along the roadway would have been costly and disruptive especially due to the slab-style construction. Any excavation along the main would require the utility to fully replace each 25ft x 25ft concrete slab and asphalt as mandated by the city’s policies. In addition to dramatically increasing restoration costs, the disruption associated with the work makes it challenging to acquire permits.
“We had teams monitoring multiple gas readings along the roadway and needed to find a solution to make the repairs while avoiding the impact to utility O&M budgets,” says Ryan McGowan, VP of Operations at ULC Technologies. “Any excavation in the road would require significant restoration efforts, including the rebuilding of the concrete slabs that require multiple days of large-scale road closures.”
In addition to repairing the current leaks, the outlook of future leaks underneath the roadway risks a high financial impact on leak repair costs.
SOLUTION
CISBOT has been utilized for robotic internal cast iron joint remediation since 2009 to help manage large diameter cast iron gas mains. The existing CISBOT solution was designed for 16”+ diameter gas mains and has been a commercial, proven solution since 2012. The 12” CISBOT robot was developed in 2022-23 through additional funding and is now another commercially viable system.
When it came time to identify project locations, the project location was identified due to the potential cost savings achievable through the project and historical challenges around traditional repair.
“The location was ideal for the 12” CISBOT deployment,” said Mersim Redzematovic, Project Manager at ULC Technologies. “There were no other viable repair or rehabilitation options to address leakage leaks that didn’t involve high cost, extensive excavation or disruptive shutoffs for customers. CISBOT was able to get the work done with the least amount of excavation possible—all while helping our customer eliminate future leak repair costs.”
Like its larger counterpart, the 12” CISBOT robot was designed to enter the live cast iron gas main through a small excavation in the roadway. From inside the main, the robot rehabilitated each joint by injecting an industry-proven sealant at every joint it was able to access. The 12” robot utilized the same joint sealing processes as the larger CISBOT robots, which have sealed tens of thousands of joints over the past 15 years with a proven record of success.
PROJECT RESULTS
ULC’s crews were able to successfully seal 59 joints from within the 12” diameter low-pressure cast-iron gas main over a period of 15 working days. Gas readings were monitored throughout the project, showing that the robot was successful in sealing the existing leaks. The robot sealed all other joints in the main to protect against future leaks along the 600ft section of pipe.
Positive results from the project helped address gas readings in the street reduce costs through both a reactive and proactive approach to managing this critical asset.
The gas readings along the street were problematic due to the high cost and disruption associated with traditional leak repair. In the above image, the bar hole reading chart shows pre-sealing (orange) and post-sealing (green) gas readings, illustrating the effectiveness of the 12” joint sealing project. The new iteration of CISBOT was able to resolve the leaks while protecting against future leaks.
To learn more about 12” CISBOT visit our web page or contact us.