Pitch fibre drains and pipes were first laid in the UK during the 1960’s as a cheap alternative to the standard clay pipes and in recent years have been the cause of many blockages. This failure rate is generally due to the age and usage of the pipes and results in to the delamination, blistering and deformation of the pitch fibre pipes. Their installation is now banned under the current building regulations and alternatives have to be used.

All clay and concrete pipes are classed as rigid pipes and are designed and installed as such. In general engineering terms pitch fibre pipes were the first of the “flexible pipes” to be installed, however, in the 1960’s the engineers / civil engineering industry did not understand or appreciate the difference between flexible pipe design and installation and rigid pipe design. This has now led to a lot of the pitch fibre pipes to deform and collapse causing both serviceability and blockage problems.

The cured-in-place lining (CIPP) has greater ring stiffness than the pitch fibre pipe and therefore gives added support to resist deformation and other common problems. The same linings are used to renovate clay and concrete pipes within the water industry around the world and are designed and tested to last for 50 years providing a long lasting solution to a pitch fibre drain problem.

All Dynorod CIPP linings comply with the basic requirements of:

• BS EN 13566-4:2002: Part 4: Plastic piping systems for the renovation of underground non-pressure drainage and sewerage networks – Lining with cured-in-place pipes.
• Water Industry Specification (WIS) 4-34-04: Specification for renovation of gravity sewers by lining with cured-in-place pipes: March 1995: Issue 2, published by the Water Research Centre (WRc Plc).

Each individual lining is designed, in accordance with the Sewerage Rehabilitation Manual (SRM), to withstand the long term effect of external hydrostatic pressures (i.e ground water) acting on the lining over a 50 year period.

If you need renovation work carried out on your Pitch Fibre pipes call Dynorod on 0845 026 0994 for a free quotation from the drains experts.

Dual Access (Manhole to Manhole)

In general, the patented No-Dig method used by Dyno-Rod to renovate pitch fibre pipes are as follows:

1. A steel cable is introduced through the centre of the pitch fibre pipes.
2. A steel reformer / cutter is then pulled through the pipe to remove any surface blistering or delamination.
3. The steel reformer is then winched through the pipe several times so as to re-round the deformed sections of the pipeline.
4. Finally, a polyester lining is pulled through the pipe, inverted and then cured in place restoring the pipeline back to its original shape.

Single Access (Manhole or Excavation)

In general, the patented No-Dig method used by Dyno-Rod is as follows:

1. The re-rounding head is attached to both a steel rod and a winch cable.
2. The head is then pushed through the pitch fibre pipe using the steel rods.
3. The head may also be vibrated through a heavily deformed section (minimum diameter is 50mm) by attaching a kango drill to the end of the steel rod.
4. The steel rod is rotated anti-clockwise to unlock the re-rounding head when located at the correct position.
5. The re-rounding head is then winched back to the launch manhole re-rounding the pitch fibre pipe.
6. The process may be repeated several times to re-round the deformed sections of pipe.
7. Finally, a polyester lining is pulled through the pipe, inverted and then cured in place restoring the pipeline back to its original shape.

With respect to the rehabilitation of pitch fibre pipes other organisations are now offering similar services, some of which are in breach of the patent and as such are being contacted by the relevant authorities.

The first pitch fibre repair was carried out in Trivills Park, Liskeard, Cornwall in the spring of 1996 in conjunction with Royal Sun Alliance. Since 1996 Dyno-Rod has renovated over 150km of pitch fibre pipes and is now an accepted approach recognised by the environmental health people, in Cornwall, in restoring full flow conditions.

Since this time a spokes person from Royal Sun Alliance has declared that “Pitch fibre pipe drainage problems have been increasing steadily over the past few years and are proving expensive to solve, but the insitu technique is offering us huge savings, sometimes more than 50% compared with standard excavations.”

Call Dynorod on 0845 026 0994 for a free quotation from the drains experts.