Repairing Pitch Fibre Pipes

Ian Clarke — Jan 01, 2006

The Channel Island of Jersey is the largest of the Channel Islands and lies in the Bay of Mont St. Michel off the coast of France.

Since 2000, Bell Services Ltd., the island’s Dyno Rod franchise holder, has been lining drains across the island, initially using polyester based resin liners on mains of 100- and 150-mm diameter along with a few pipes of 225-mm diameter and one of 400-mm diameter. The company undertakes drainage work for municipal, commercial and domestic customers.

Since 2004 the company has only been installing epoxy or silicate resin based liners in the 100-, 150- and 225-mm diameter range. According to Paul Stephens, manager of Bell Services, “We find installing epoxy or silicate resin based liners easier and quicker than lining with polyester resins and we can do this without the hassle of importing dangerous chemicals into Jersey, all of which must come in by boat, meaning that it was something of a nightmare as the chemicals had to be shipped separately. We have also found it very beneficial lining with epoxy and silicate resins as they bond to the host pipe. This has enabled us to line all types of pipe material and these products are especially good where there is root ingress. We currently use the German-manufactured Brawoliner system, from KOB [Karl Otto Braun KG] of Wolfstein.”

Since starting to use the Brawoliner system some 2,000 m has been installed in 100- and 150-mm diameter, with some 225-mm diameter installations. The work has been undertaken in close association with CJ Kelly Associates Ltd., an independent sewer renovation consultant and KOB’s technical representative in the United Kingdom and Éire.

The Brawoliner system is manufactured to ISO9002 standard and uses a seamless lining textile fabric that is applicable to pipes from 75 to 255 mm in diameter, with wrinkle-free installation around 90 degree bends. The system is generally compressed air inverted from an inversion drum and can be used as an ambient or hot water cured installation.

Pitch fiber drainage pipe was installed in vast amounts during the late 1960s and 1970s, which has meant that Bell Services has been called upon to re-round and line both domestic and commercial drains made from this material.

A typical example of a project undertaken by Bell Services includes the renovation of a pipeline serving a number of blocks of flats managed by Rumsey Management, totaling around 50 residences, on a private estate in St. Brelade, Jersey. The sewer system serving the community was a 150-mm diameter pitch fiber pipe, running at depths of between 1 and 3 m, which on CCTV inspection showed some deterioration, although not to the point of collapse.

The project as a whole included the open-cut replacement of some of the pipeline, but large sections of the work could be rehabilitated using lining techniques. In all, some five lengths were lined using manhole-to-manhole lining. The lining runs included two lengths of 100 mm in diameter that ran beneath buildings, one length of 100 mm in diameter that ran under a garage, one 86-m long section of 150 mm in diameter that lay beneath a road and, ultimately, two further 45-m lengths of 150 mm in diameter. All of the installation sites were in sandy ground.

The majority of the installations were completed with relative ease using standard compressed air installation, although prevailing conditions on the 86-m long run meant there were difficulties in completing the inversion. Having experience with the long lining run, Bell Services decided to reduce the length of the final linings by installing a new manhole halfway along the proposed length. This allowed the final lengths to be made as two 45-m runs instead of another single 90-m shot. This approach meant that the project was successfully competed on schedule.

At another site, the company encountered badly deteriorated 100- and 150-mm diameter pitch fiber pipe that ran beneath a shopping center. This job was complicated by several factors, including that one of the shops had laid a concrete floor over a manhole. The manhole at the head of the run was situated in the back of a bank and the bottom end of the run passed through two manholes in a shop that was open for business from 7 a.m. to 9 p.m., seven days a week.

The project entailed providing adequate temporary toilets and washing facilities for both the male and female staff, which was achieved by providing a large portable unit at the rear of the property. The work was undertaken over one weekend starting on the Saturday in the bank and lining 35 m of 100-mm diameter pitch fiber pipe through the bank, a drycleaners and a hair and beauty shop. The work finished on the Sunday, at the other end of the shopping center, with the lining of 20 m of 15-mm diameter pitch fiber pipe beneath the supermarket and a medical clinic. All the work was completed without any disruption while satisfying the requirements of the security team in the bank, as well as both the maintenance teams at the bank and at the supermarket. The latter was achieved with the presentation of method statements and risk assessments. In an interesting aside, the section of pipe beneath the drycleaners had to be lined with a silicate resin system due to the extreme temperatures of the wastewater coming from the business.

Bell Services also undertook a successful operation to line an aged and deteriorated clayware pipe running under a bar in the island capital of St. Helier. The pipe ran from a 2-m deep manhole in the rear of the bar and under the building. Its diameter changed from 150 to 225 mm at about 9 m in, with an inline junction serving the bar and a neighboring property at about 20 m into the run. From here, the pipe then ran out into the street beneath a busy road and into the main sewer, at approximately 3 m deep. The job entailed lining the 150-mm diameter section in one direction, to the point of the diameter change and lining in the reverse direction on the 225-mm diameter section, again up to the point of the diameter change, from an excavation outside the bar. The operation was completed using a Patch Box installation, a localized repair lining system jointly developed by Ant Hire Ltd. and CJ Kelly Associates Ltd. in the United Kingdom, which was used to cross the diameter change point sealing the linings and joining them together. The junction in the pipeline was then opened using a robotic cutter.

Rescue Mission
In a rather unusual turn of events, Bell Services quoted for a project involving the re-rounding and lining of foul drains serving a block of flats. This involved lining beneath the flats and under another property back to three internal stack pipes. Unfortunately, the initial tender was unsuccessful. However, while attempting to re-round the pitch fiber pipe, the company employed to undertake the work damaged it causing it to collapse at a point under the neighboring property. So consequently a new drain had to be installed around the building. The company undertaking the project lost confidence and decided not to try to re-round and line the remaining three runs under the flats to the stack pipe.

Bell Services was asked if it was still prepared to undertake the remaining work, which it was more than happy to do. A plumber cut and removed the bottom sections of the stack pipes and the pipeline was re-rounded and lined from the relevant manhole up the stack pipe and into a piece of pre-cut, 110-mm diameter u-PVC pipe. This allowed the plumber to connect the new pipe work directly onto a u-PVC coupler, leaving the client pleased with the outcome.

These operations, and others, have shown very effectively the flexibility of lining for smaller diameter pipeline repair works.