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Targeting London's Victorian Water Mains with New Clean Water Renovation Systems
Insituform Blue® is a division of Insituform Technologies® Inc. devoted to the clean water network renovation business. Insituform Blue® currently operates in North America and Europe, with the latter office based in Paris, France. Both operating centres also offer support to the relatively new and expanding operational division of Insituform Technologies in Southeast Asia. On a recent project in central London, the European division of Insituform Blue® introduced two new water pipeline renovation products to the UK, InsituFlex™ and InsituFold™.
LONDON WATER MAINS UPGRADE
As the UK’s capital City, London was one of the first served by a drinking water distribution system. A significant portion of the network was installed during Victorian times, and whilst Victorian engineers were good and installed long-lived systems, they were not designed to last forever. With pipelines between 80 and 120 years old and over 50% of the Central London network being over 100 years old, it should not be surprising that they are showing signs of wear.
As such Thames Water (the UK Water Company responsible for drinking water and sewerage services in the London area and much of southeast England) has, for the past few years, been undertaking its ‘Victorian Water Mains Upgrade Programme’, and replacing or renovating these ageing, deteriorating and often leaking water mains networks. The series of multi-million pound projects has involved the use of multiple construction techniques including trenchless techniques when viable and appropriate to minimise disruption to both residents and businesses in this very busy city. In some areas, as much as 56% of works have been completed todate using No-Dig technologies, with a significant amount of the work being completed along streets in some of the most densely populated, high property value areas of the country.
The Maida Vale district in the Borough of the City of Westminster in Central London is one such area. Here, streets often comprise large, densely packed Victorian terraced houses, valued in hundreds of thousands (if not millions) of pounds.
 An aging 300 mm diameter cast iron water main in need of refurbishment runs beneath Maida Vale. The main contractor for the work in the Maida Vale area is Laing O’Rourke Utilities Ltd, one of several major contractors being used by Thames water for the Victorian Mains Replacement works. Laing O’Rourke has subcontracted part of its work to Instiuform Blue to provide specialised lining systems for various sections for the pipelines.
The work being undertaken by Insituform Blue® comprises some 1,065 m of pipeline comprising lengths of between 155 m to 550 m. The work is taking place in three phases, each utilising the InsituFold™ system. Phase 1 involves two 180 m lengths running beneath Warrington Crescent, Phase 2 comprises some 550 m of lining and Phase 3 (the shortest section) is 155 m, both beneath roads in the Warrington Crescent area.
INSITUFLEX™/INSITUFOLD™ LININGS
The InsituFlex™ pressure pipe lining system has been under development by Insituform Blue® since early 2006. Designed to answer current lining requirements in the water supply industry, the system drives circular Polyethylene (PE) pipe through specially designed rollers. A winch is also utilised to aid the passage of the liner through the host pipe. The rollers reduce the liner pipe diameter (by about 10 %), allowing it to pass into the host pipe being lined. Once fully installed in the host pipe, the liner ends are expanded out and fitted with end connections. Next, the liner is filled with water and pressurised, causing the liner to revert towards its original diameter inside the host pipe and achieve a close fit. The InsituFlex™ product is currently designed to operate in host pipes from 100 mm diameter up to 450 mm diameter.
InsituFlex™ material can be designed to form either a fully structural lining using thicker wall, lower SDR value PE pipe or a semi-structural/interactive liner using a higher SDR value PE pipe. The latter relies on the host pipe having some residual strength which the liner utilises to fully withstand internal pressures once in operation.
 In parallel to this development, Insituform Blue®, developed InsituFold™, which is appropriate for work in larger diameter pipes over longer distances. As the name suggests, this system forms PE liner pipe by folding it into a ‘U’-shaped profile to reduce its effective diameter for easy installation into the host pipe. To do this, the pipe passes through a specially designed ‘folding’ rig. On this rig a hydraulic pushing machine advances the liner pipe through guide rollers and pipe folding wheels. The end of the liner is attached to a winch at the reception pit which guides it through the host pipe during installation process.
To ensure that the liner does not revert in the host pipe until required, the folded pipe is strapped as it exits the folding rig. This strapping holds the folded liner in its ‘reduced diameter’ profile until the lining pull-in is completed. Once the pull-in is complete the liner ends are opened out using air bags and end connections are fitted. The liner is then filled with water and pressurised to burst the banding and re-round the liner, again achieving a close fit lining of the host pipe. InsituFold™ can be utilised on pipe diameters from 300 mm up to 1,400 mm.
Both systems utilise a lubricating bentonite slurry which is painted on the outside of the liner as it passes into the host pipe in the launch pit. This slurry reduces the installation tonnages required to pull or push the liner through the host pipe, a significant requirement with longer lining lengths.
 The InsituFold™ system also has the ability to operate as a butt and pull process, where shorter lengths of pipe are joined together during installation to make up the final lining length, thereby reducing the overall site footprint. Due to the demands of working in such a congested area, InsituFold™ was deemed to be most applicable for the Maida Vale project.
WARRINGTON CRESENT
The two 180m lengths of lining work in Warrington Crescent were the first in the UK utilising the new PolyFold™ lining system. The existing pipeline comprised a 300 mm diameter cast iron main, acting as a feeder main for the area. Pressures in the existing main are expected to be up to 6 bar once the lining operation is completed. Because it was a feeder pipe rather than a domestic supply service, the main did not require major excavation to enable domestic connections for disconnection or reconnection.
A significant problem however, was severe tuberculation which, in part, was the reason behind the need for the project. The pipeline required very extensive cleaning work before lining could take place. Once cleaned, the pipeline was inspected to ensure that no obstructions existed along the required route, and the preparations for lining could begin.
At the reception end of the liner run an access pit was prepared to take the liner support winch.
At the launch end of the project, several lengths (approximately 50 to 60 m long) of butt welded, SDR 26 PE-100 pipe were prepared and laid out. The first length was positioned in the folding rig and fed through to create a folded lead end. A towing head was then attached to the lead end and attached to a previously positioned winch cable running through the length of the host pipe. When all was prepared the lining run commenced.
The folded PE pipe exited the folding rig was strapped, at approximately 300 mm intervals, to ensure that the folded form was maintained throughout the installation. When the end of the first liner section neared the folding rig, the next section of liner pipe was welded to the free circular end using a McElroy-manufactured, TracStar 500 track-mounted, butt welding machine, which had been used throughout the works to complete pipe welding during the preparation process. The initial PE liner pipe lengths were prepared from 12 m pipe sticks provided by pipe manufacturer GPS.
The first 180 m installation process took approximately six hours to complete, including four further butt welding operations to complete the required 180 m of liner.
A further length of lining was required on Warrington Crescent extending from the launch pit of the first run a further 180 m in the opposite direction. To achieve this, the original launch pit was to install from the opposite direction. This allowed Insituform Blue to minimise the excavations required (just three in total). Ultimately these lengths were joined together and reverted as a single section.
Given that the sites in Maida Vale were the first use of the new InsituFold™ systems ‘in anger’ in the UK, all the lining operation went very smoothly. Commenting on the works Ian Jones, Operations Director for Insituform Blue®, said: “We are very pleased with this first installation. This is also a very interesting and exciting time for us all. With the establishment of Insituform Blue®, we are at the start of a whole new venture into the area of water supply and other pressure main renovation. The ultimate aim for Insituform Blue® to expand across Europe and then across the globe with the innovative new InsituFlex™ and InsituFold™ product lines.”
INSITUFORM BLUE®
For over 35 years, Insituform Technologies® has, been a well known, recognised and well-respected name in the global sewer and industrial pipeline renovation sectors using its Insituform Process CIPP lining system. However, over the past few years, much of the worldwide utility industry focus has shifted towards the use of trenchless technologies to renovate and rehabilitate pressure pipe networks. Whilst Insituform has been expanding its product portfolio extensively across the variety of trenchless methodologies now available it has not, until now, offered practical, cost-effective lining solutions for utility-type pressure pipes. Insituform Blue® was established to plug this gap in Insituform’s range.
As part of its expanding portfolio, Insituform Technlogies Inc acquired United Pipeline Systems (UPS), a specialist pipeline contractor which utilised the Tite Liner® high-density polyethylene (HDPE) lining system for lining pipelines, to protect them from abrasion and corrosion, in diameters from 50 mm to 1,320 mm diameter. Whilst, in the main, applicable to longer length, larger diameter pipelines, straight-run pipelines, Tite Liner® was not well-suited to smaller diameter shorter length utility type pipelines with the potential for bends, valves, connections etc. The basic technology however was viewed as having the potential to be developed into something that could be applicable to the utility market.
So, early in 2006, Insituform Blue began development work on the InsituFlex™ and InsituFold™ product ranges. Whilst essentially similar in concept to Tite Liner®, the products ultimately developed were sufficiently different to warrant a new designation.
Looking at the pressure pipe market, the move towards renovation of aging clean water supply networks and gas supply pipelines around the world has become a primary target, hence the products use on the London Victorian Mains projects.
For the future, Insituform Blue® will focus its core business on building an expertise in the expanding PE market for pressure pipes. However, it should be noted here that the new InsituFlex™ and InsituFold™ systems do have applicability to the dirty water market also, as seen with the company being awarded a forthcoming project in Matlock Bath, Derbyshire, UK which will involve the use of the InsituFold™ product on a sewer rising main.
At present operating companies have been established that, in the European arena, work in the UK and Ireland, France and Spain, as well as operations covering both the USA and Canada. Insituform Blue® is also in the process of advancing into Eastern Europe with an operating base in Poland currently being developed.
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