The Cast Iron Joint Sealing Robot (CISBOT) is a remotely controlled robot which we are using to repair and upgrade gas pipes in some of the busiest streets across our networks.



The CISBOT, developed by our partners ULC Robotics, works by ‘crawling’ along the inside of a gas main, sealing any leaks in the joints using a special sealant solution. It allows road users and pedestrians to get on with their busy lives, as the robot can cover large sections of gas pipe underground from just a single hole (the 'launch' point) in the ground.

Watch this short video to find out more about how CISBOT works, and read about some of our major works using CISBOT below.

Upgrading the gas pipes in Sloane Square

Throughout 2020, we are upgrading the gas pipes in Sloane Square, London using CISBOT. The map below gives an overview of how we have planned to complete this work in stages.

Case studies

The Strand


The task: Upgrade a 675m section of 24” cast iron main and eliminate ongoing gas leaks, from Trafalgar Square to Aldwych
Duration: 7 weeks

Cadent engineers were working close to The Strand, undertaking emergency gas works. ULC Robotics stepped in at short notice to support.

CISBOT successfully upgraded a total of 185 joints across the 675m section of 24” main.

All gas leaks were successfully eliminated, including one outside the busy Waterloo Bridge junction - all the while maintaining access for road users.

Oxford St

The task: Upgrade 1.3km of 18” cast iron pipe
Duration: 12 weeks

Following the successful trial at The Strand, local authorities granted permission to undertake this project within a matter of days. CISBOT successfully upgraded a total of 357 joints across the 1.3km of cast iron main.

The work prevented a gas leak that could have resulted in 700 people being evacuated from their workplace.

4 million people per week walk up and down Oxford Street. Those pedestrians and the local highways were never at all impacted during the operation.