Drainage pipe repairs, working alongside Cadent Gas Network

The Task in hand: 

AJS Environmental were called out in confidence to ensure the repair works was carried out to a high standard.  Three surface water pipes had been damaged during excavations when installing a new gas main in the street.  Two 150mm diameter clay surface water pipes had been damaged and one 225mm diameter clay surface water pipe, all these pipes have been badly damaged and needed repairing with immediate effect.  AJS Environmental was contacted late afternoon on a Thursday and we responded the following day to carry out the repair works. 

Works Carried Out: 

When arriving on site the surface drainage water pipes were full of debris from the excavation, our first job was to get these lines clean and clear to avoid the debris from traveling down the line.  Using a high pressure water jetting unit, we cleaned out the lines pulling all the debris back to the manhole allowing us to remove the debris from the system.  Once these lines were clear we then was able to carry out a survey of the damaged pipes.  A CCTV surveying unit carried out the survey on the pipe work for evidence for the client allowing for a report to be produced, also allowing the team on site to measure the length of CIPP (cured in place pipe) that was needed to be installed into the pipe.

Once the length of damaged pipe has been measured the liner was cut to the correct length, the epoxy resin mixture was then poured into the CIPP sleeve ensuring a full equal coating.  This section of CIPP was then inserted in to the correct place within the damaged pipe allowing for the inversion tube to be inserted inside of the sleeve.  Once the inversion tube was inserted into the beginning of the sleeve, this was then inverted up to the correct pressure which allowed the sleeve to mould to the pipe.  Keeping a constant pressure in the inversion tube this hold the sleeve tight to the pipe which then allows the resin to set an cure. 

After the CIPP has cured into place the inversion tube was removed leaving the epoxy liner secured into place.  The above steps were repeated downstream to repair another damaged section of pipe work.  On completion of the liners being install a CCTV surveying unit carried out a post survey on the installed liners ensuring the correct coverage of the damaged areas, a report of pre and post was handed to the client for their records. 

A larger 225mm diameter pipe was badly damaged during excavations for the new gas mains.  There were a vast amount of debris in the pipe, using a high pressure water jetting unit we cleaned out the line pulling all the debris back to the break in the pipe.  This then allowed us to remove the debris from the broken section of pipe stopping the entering the system which could cause major blockages.  Once the cleaning of the pipework had been carried out the damaged section of pipe was excavated and removed, allowing for the new section of pipe to be set in place.  The ends of the existing pipe had to be prepared and cleaned in preparation for the collars to be installed ensuring a water tight fit. The new section of pipe was cut to the correct length on site, this was installed into place tightening up the collars connect the existing to the new section of pipe work.  The reinstatement works were then carried out by another subcontractor to Cadent who reinstated all road and foot path repairs. These works were completed within 1 shift.

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