The North of England has long been famous for not just its wonderful landscapes, world renowned cities and the character of its people, it is also globally recognised as a major centre in the growth of the industrial economies we see today. Whilst like many parts of the UK the region has had its ups and downs alongside the vagaries of the economy it still boasts some of the UK’s largest industrial facilities.
Not least of these is a major soft drinks manufacturing plant which was recently the site of a challenging pipeline rehabilitation project undertaken by DALROD, a family run drainage industry service provider established in Peterborough in 1985. The project was completed using the BRAWOLINER® HT CIPP liner system, supplied by the UK Brawoliner distributor C.J. Kelly Associates of Peterborough. The project had apparently been looked at by other rehabilitation contractors but dismissed as not possible using currently available techniques.
At first glance it might appear to be just another pipe rehab project comprising the lining of some cast iron wastewater pipeline that carried effluent away from the soft drinks production process.
Reality proved somewhat different however. Pipe diameters varied from 100 mm (4 in) to 300 mm and comprised both surface and foul pipelines. The number of linings over the period of the works was numerous with Phase 1 of the programme occurring in 2014 and Phase 2 being completed in early 2015. The temperature of the effluent varied depending on the process being drained and the production cycle. The pipelines locations also varied considerably with some running under production line factory floors. This meant that timing of the individual lining operations was a vital part of the rehabilitation process. Whilst some areas of work were undertaken during process line close downs, other works had to be undertaken off shift to ensure that overall no production loss at the factory occurred.
In trying to establish the degree of deterioration in the pipelines, investigations showed that the acidity of the varying temperature plant waste had damaged the pipe to the extent that the invert had in some areas been eroded so much that it had led to exposure of the sub-soils beneath. In others the pipe fabric was so thin there was no chance of running equipment on it as it was believed it would collapse under the strain. This meant that utilising standard rehabilitation techniques would be impossible.
Mike Pollard from DALROD Cambridgeshire liaised with John Kelly from C.J. Kelly Associates. Using previous experience from other sites and carrying out some technical data testing against the Brawoliner data sheets it was proven that the BRAWOLINER® HT product was best suited for the job.
The BRAWOLINER® HT system offered the best solution because it was not only chemically resistant to the required specifications set out by the client, it was also flexible enough to negotiate the numerous bends on the pipe route.
The project complexity came into play during the pre-lining survey. As the base of the original pipe was missing in many areas, pulling a camera system through to complete the pre-project survey and plot lateral positions for reopening later was technically impossible using standard CCTV survey equipment. The deterioration also meant that even with the best CCTV system it was often impossible to effectively plot lateral positions. DALROD therefore had to devise a special method which comprised pulling a cable line through that ran along the pipe roof. This then allowed the contractor to pull a camera system through to plot the laterals that could be seen and pass through a cutter robot to excise any obstructions in the pipe that might impede the lining process.
Once this process was completed lining could commence. Even then a change to the standard lining process had to be adopted. To ensure that new liner inflated in the host pipe correctly, given the missing invert sections, it was decided to introduce a pre-liner to form the new shape of the liner so preventing the BRAWOLINER® HT liner from slumping into the ‘V’ of the eroded invert channel. This allowed the new liner to form the correct pipe shape during curing.
So, once the liner had completed curing, the now correct-shaped pipe allowed the lateral reopening robot to be inserted to undertake the lateral re-opening works without fear of it falling into the erosion channel beneath the host pipe. This was also where one other aspect of the BRAWOLINER® HT also proved useful on the project. Its flexibility meant that the liner profiled well into all the lateral connections, so when it came to reopening laterals the robot cutter operator found not only those that had been highlighted by the initial survey but also others that had not.
Commenting on the project DALROD’s Mike Pollard said: “This was a very challenging job, however it went reasonably smoothly as our team had previously worked at this site and had learnt from previous experience. The work programme was completed 3 days ahead of schedule with all of the lining runs completed. The project also included some construction work and the installation of a new stainless steel catch pit into the floor of the factory to act as a catchment under the machinery to collect any over-spill of liquid which would previously have potentially caused erosion of the floor. All-in-all, the customer was delighted with DALROD Cambridgeshire’s turnaround time, pricing and attention to detail. On site daily meetings also kept the client up to speed with progress. DALROD as a company thrives on taking on challenging projects where others may have tried and failed, this is another feather for the DALROD hat.”
The BRAWOLINER® HT is designed to offer pipe rehabilitation options in pipes where high and variable temperatures can occur for example in processing plants, industrial units and even kitchen or washing machine waste flows. To achieve a permanent repair the stability of any rehabilitation system at temperatures greater than 93°C is necessary. In addition, for example in Germany, for fire safety reasons, all rehabilitation solutions for wastewater pipes in buildings must meet a minimum for German building materials class B2 in accordance with DIN 4102-1 standards. The system is also DIBt approved for use in vertical pipes, making it ideal for internal building pipe work.
The world-renowned BRAWOLINER® has been modified with a special temperature-stable film. This now means that steam curing is now also possible at high temperatures. The BRAWOLINER® HT system now offers, in addition to the advantages of the tried-and-tested BRAWOLINER®:
- Negotiation of bends of up to 90°
- Potential for 2 dimension changes during a lining run
- Hot curing with steam or water
To meet the special requirements of working within a building and domestic environments the company has also developed the new BRAWO® HT resin that has been specially formulated for such use. Together with the proven outstanding features of the well-known BRAWO® resins, it meets all structural requirements including:
- Dimensional stability at temperatures > 93°C
- Meets German building materials class B2 requirements in accordance with DIN 4102-1
- Can be cold or warm cured
For C.J. Kelly Associates John Kelly, Senior Partner said: “Given the state of the host pipe this was never going to be an easy installation for anyone. Working together with DALROD, using its wealth of field experience allied with the technical excellence of the BRAWOLINER® HT product, it was possible to achieve an outcome for the client that no-one else seemed to be able to offer. A success for all concerned.”