A Truly Trenchless Solution

What is Picote Flexi-Sliplining?

It's a simple way to renovate gravity sewers DN100-300. Flexi-Pipe (Flexirohr) is a DIBt certified tri-layer PE pipe, exclusive to Picote Solutions and our partner Renos Oy , an inner thermoplastic elastomer layer creates the flexibility which means that the pipe can effectively be turned in on itself to enter the manhole. The Pipe has also been HPWJ tested to 180 bar by WRc in accordance with WIS 4-35-01 2008 appendix B. As with all Sliplining systems, there is a slight loss of inner diameter, which in this case does not affect flow, owing to the smooth inner skin of the pipe which in some cases even improves the flow rate because it is much smoother than the host pipe. The ring stiffness class of the pipe is SN8 (DN 270 Flexi Pipe is SN4). Whilst an ideal solution for main line sewers, in the diameter range, the system is also particularly applicable to rehabilitation of house connections.

What makes it different from existing Sliplining systems?

Unlike traditional Sliplining systems, there is no need for a 'lead-in trench'. Training is minimal, with as little as a two-man crew required and installation failure carries an extremely low risk. The annular gap at the manhole is sealed with grout. A system that can negotiate some bends, Picote Flexi-Sliplining provides a successful installation, regardless of the condition of the host pipe. Without bypass pumping and with the pipe remaining in service throughout, the fully welded, factory produced pipe requires no curing, potentially reducing the time required on site. Pull-resistant couplings are available.

Picote R&D worked with Renos Oy redesigning existing and developing new equipment to produce high-end tools, so the process could be adopted for trenchless projects globally. These include the unique tools for the welding process: welding rig, welding inserts, pipe cutters, pulling heads and welding balls. Also, the equipment helping the installation via pulling in of the pipe has been significantly redesigned. All of these new tools make the installing process easier, faster and more efficient. The tools are simple, light-weight and have good ergonomics.

Preparation is key

Prior to installing the new pipe, the host pipe needs to be cleaned to remove any debris, scale, roots or any intruding connections. Any large displaced joints may have to be ground away. This can be easily achieved (depending on the lengths involved) via high-speed cleaning with Picote Millers and Cleaning Chains.

The welding process ensures that Flexi-Pipe joints are stable and remain able to bend in the same manner as the original pipe. Without this facility there would be potential for the pipe to separate during the installation process as the weld is under stress due to bending. This is not a concern with the Picote Welding Rig.

Instead of huge reels of pipe at the worksite, it is possible to take 6m sections and weld them together (for DN150 and above, otherwise 50m coils). This means less transport weight, cost, fuel and waste. First, the new Picote Pipe Cutter trims the end of each side of the pipe for a flush fit. Then, the Picote Welding Ball is inserted and inflated so that the pipe sections are welded together using electro-fusion, without creating a welding bead on the inside of the pipe. The ball is then deflated and pulled out. The welding process takes approximately 10 minutes, but two welding rigs on site maximises productivity during that time, potentially creating 2 x 12 metre lengths simultaneously.

The new Picote Upper Pipe Guide directs the flexible liner pipe through an existing manhole without the need for extraneous excavation, making it a truly trenchless technique. Utilising a pulling head and a 2T winch the pipe is pulled through. With a small worksite footprint, these new installation tools complement the Picote Flexi-Sliplining System to offer a low carbon, low water usage rehabilitation method, safer for operators as well as time and cost efficient.

Environmental Benefits

A fully trenchless method, Picote Flexi-Sliplining can be manhole to manhole, installed via existing manholes owing to Picote designed equipment, negating the need for bypass pumping. The new stand-alone DIBt certified pipe is SN4 or SN8 depending on diameter, offering a new pipe for 50+ years, with no emissions in the air or water either during or after installation. There are no hazardous chemicals, making this safe to use for operators. No toxic waste is produced and due to the minimal oil used, there are less raw materials utilised, meaning even less CO2 emissions! Easy to transport, store and handle, the pipe is very lightweight and offers a very fast installation of around 8 metres per minute, meaning less disruption to traffic and residents. Longer installation lengths increase the capabilities. Preparing the pipe on site means minimal waste, the pipe is in 6m sections (depending on diameter), making it easier to transport to site. Specialised welding and other equipment makes this a fully trenchless pipeline rehabilitation method. The equipment is also very portable and lightweight, offering an even lower worksite footprint!

NEW Innovation

Successful testing has just been completed in-house for lateral connections. The method involves installing the new Picote Connection Collar System at the joint. The opening can first be created either from the lateral using the same Picote Miller that first cleans the mainline pipe, using a Twister lateral Cutter, or via the main utilising the Schwalm Talpa Robot. Picote also has a strong cooperation with Schwalm Robotics. Once the opening has been created, the Picote Connection Collar can be installed, creating a seal which, unlike traditional top hat systems, fully seals both the lateral and the main pipe.

Picote has recently developed a battery winch, for longer distances, for added safety on site (no trailing cables) and negating the need for heavy winches.

Contact us or your Picote Reseller for further information about the Picote Flexi-Sliplining System.