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Yorkshire Water trials innovative sewer pipe lining technology

Sep 04, 2016

Dermot Finn, Commercial Director, Nu Flow

Yorkshire Water has undertaken the UK’s first trials of an innovative technology for lining sewer pipes. Nu Flow’s Nu Drain cured-in-place pipe liner has only just become available to UK utilities, but has already been applied widely across North America.

The pilot trials were undertaken on drains at four domestic properties involved both clay and pitch-fibre pipes. 

Bob Watterson, Technical Support Engineer NE region, Yorkshire Water explains,

“We’re looking at no-dig technologies for a lot of the day-to-day operations we carry out. By using no-dig, we’re not fuelling excavation vehicles and sending rip-out of the road to landfill and we’re not busying up roads while excavations are carried out. Also, importantly, people are unaware we’re repairing pipes while they travel about above us.”

Nu Flow technician Max Page undertakes CCTV monitoring of a domestic gully with limited access points during a trial in Leeds.Air is blown into the pipe-liner during the trial on a pitch-fibre pipe in Willerby, Hull.

Case study: Willerby, Hull

CCTV inspection found the pitch-fibre pipe serving four properties in Willerby, Hull, to be in particularly poor shape. The house nearest the main had experienced flooding, where flow had backed up, necessitating regular visits from Yorkshire Water’s sewerage team to keep the line clear.

Some of the bubble-like deformities in the pipe were up to 30cm in length and the 100mm-diameter pipe was reduced to 50mm in places.

Minimising disruption to the customer is a key part of Yorkshire Water’s community strategy and an important aspect of the pilot. One of the gardens was landscaped, so a no-dig solution like Nu Drain was highly desirable. An over-pumping system was also set up to keep the customers connected to the sewerage system throughout the trial.

Nu Flow’s pneumatic pipe-cleaning tools were introduced into the pitch-fibre sewer to take it back to its original state. The specialist carbide steel ball-head cutters can remove roots, calcite, mortar and cement and reinstate laterals as small as 50mm diameter.

CCTV inspection confirmed the pipe was clear and was also used to take a measurement of the pipe length. Each polyester ‘sock’ liner is cut and impregnated with epoxy resin, known as ‘wetting out’, on site.

The tube was then rolled around an inflatable bladder to a 50-60mm circumference. The CIPP is most commonly pulled into the pipe, but on this occasion there was only one access point so the push-rod techniques was used.

With the liner in place and one end sealed, air was forced into the other end of the bladder through a hose.  As the bladder inflated, the tape broke and the liner was pressed to the walls of the existing pipe where it was left to cure for two to three hours. 

Once the epoxy had hardened, a small piece of the liner was cut out to test it was fully cured and the CCTV passed through again to demonstrate to the client that the pipe was fully opened and clear.

Roll out

Watterson is delighted with the results of the trials and says Nu Flow’s lining systems are likely to play a key role in meeting the utility’s needs, especially on renovating the smaller diameter, householder side of the network, in the coming months and years. 

The pipelining specialist is so confident in the performance of its product that it is offering trials UK-wide.