Innovation
Semi Structural Spray Lining
The rehabilitation methods available to water utility providers have traditionally been limited to non structural spray lining or the insertion of a polyethylene pipeline into an existing asset.
However, DVS Pipelines has worked closely with both its clients and E.Wood Limited of Northallerton (a market leader in the supply of spray applied coatings) to deliver an alternative "next generation" semi-structural spray lining technique.
This next generation of spray lining, Copon Hycote 169HB, can be applied to a maximum thickness of three millimetres in one pass. Copon Hycote 169HB is approved under regulation 31(4) (a) of the Water Supply (Water Quality) Regulations 2000 for contact with potable water.
This new process delivers all the benefits of spray lining with the additional advantage of structural support, providing fifty years additional life to the receiving asset. Semi structural pipeline spraying provides long term spanning of fractures, with sufficient toughness to survive dynamic loading at the fracture point, sufficient ductility to accommodate joint rotation after fracture, strength to maintain longitudinal continuity after fracture has bridging capability and capability to accommodate local damage to the host pipe.
With just a one hour cure time speed is another prominent feature. This is primarily due to the fact that unlike other rehabilitation techniques the approach does not require reconnection of service pipes, therefore, it is possible to rehabilitate pipes and return them to normal service within just a single day.
DVS Pipelines was the first company in 2005 to be WRc approved to apply a three millimetre lining in one single application using Copon Hycote 169 HB.
DVS Pipelines has also successfully conducted manhole to manhole rehabilitation to waste water pipes using Copon 169 SL (a similar formula to the 169 HB used in clean water applications). Copon 169 SL was developed as a solution to specifically combat the increasing problem of infiltration into the sewerage system.
Whilst conventional no dig lining techniques consolidate the strength of a pipe, it offers little protection from infiltration due to liner shrinkage. With 169 SL there is no liner shrinkage, thereby eliminating groundwater flows from entering the sewer between the liner and the host pipe.
Once again, speed is a particularly important advantage of this approach. As in the fresh water rehabilitation, service pipes do not require reconnection, resulting in return to normal service in one day.
In summary, both these semi structural pipeline spraying process are useful additions to DVS Pipelines' portfolio of no dig techniques. The early indication is that this new innovative approach is set to command a significant proportion of the ever increasing no dig market. With some clients claiming to have projects for which these semi structural approach is the only option available to them because of time or digging constraints.