Monday, July 15, 2024

CIPP inside the building

A critical advantage claimed for NuFlow’s NuDrain and NuCure UV CIPP liners is that they achieve a full-length, full-area tight frictional interface seal

NuFlow’s Precision PIP (Push or Pull-in-Place) installation methods with its integrated inflation bladders have specifically been developed for the small diameter, inside the building and under slab market. Most other CIPP installation methods were developed and optimised for the volume utility sector, with long lengths of larger diameter pipes.

A critical advantage claimed for NuFlow’s NuDrain and NuCure UV CIPP liners is that they achieve a full-length, full-area tight frictional interface seal, rather than relying upon local end-seals that can actually damage the structure of a CIPP liner. Furthermore, hydrophilic seals will periodically leak unless kept continuously wet. Such small, intermittent leakage may be considered acceptable for exterior buried utility work, but only zero leakage is acceptable inside of a building footprint, especially above ground.

NuFlow’s products are specifically engineered to limit risky resin bleeding, in addition to the outer coating, it also relates to the denser felt tube design and the viscosity of its resins, precisely because NuFlow’s market focus is inside of the building and in smaller diameter piping systems where correcting such common construction challenges becomes much more disruptive than in typical utility sector projects.

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The company’s tube design also permits better negotiation of bends, which tend to be more frequent in plumbing and mechanical piping, with less risk of twisting and excessive wrinkling, and with a more consistent as-built structural wall thickness.

In the smallest diameter pipes, robotic reinstatement at remote branch connections is not always practical or even possible, and the overlapping of connection liners at a reinstated service connection can result in an excessive reduction of the inside diameter. NuFlow’s Precision PIP gives the additional option of ‘gapping’, or leaving the branch connection, ‘Y’ or ‘T’, un-lined) together with its Vertical & Horizontal Connection Liners (VHCL) to achieve a total lining system in applications where other processes would resort to more disruptive and costly measures, including additional excavation.

With time sensitive installations, the option of ‘gapping’ would allow for immediate return to service without having to wait for the much longer process of robotic connection reinstatements and, as required, the VHCL’s for the branch connections can be independently installed during a separate phase of the work, or at least on a different day. The methods utilised is determined in consultation with the customer to best meet the project goals and needs.

Lastly, all CIPP liner products certified for plumbing use inside of the building envelope must also be free of VOCs (Volatile Organic Compounds) and HAPs (Hazardous Air Pollutants), the bulk of the CIPP products used in the exterior utility sector do not meet these requirements.


NuFlow’s Precision PIP installation methods permit precise monitoring of placement with a CTTV camera, easily avoiding under-shots or over-shots during liner insertion, which is absolutely critical when lining ‘blind shot’ branch pipes, and ensuring that joints and fittings near the end of the liner are properly sealed with extremely precise and reliable placement. Inversion and traditional pull-in-place practices are simply not capable of such precision placement and are also higher risk for insertion through multiple bends.

Furthermore, inversion comes with the likelihood of air pressure ‘burps’ disruptively blowing out traps within the building. In small diameter building pipes, NuFlow’s Precision PIP generally lowers required installation time and provides superior performance as compared to inversion, which would generally be preferred only on long length manhole to manhole utility pipe runs which have access at both ends.

The NuFlow advantage is clear. Simply put, no leakage is acceptable within the building envelope. NuFlow’s containment of the resin also greatly reduces the construction risks associated with resin slugs up remote branch connections and with uncured resin left within the building envelope, especially where missing host pipe sections can result in extensive resin bleed off. This is a particularly high-risk situation in inaccessible pipes within walls or under slabs. The limitations of available robotics in small diameters means one cannot always clear such a resin slug, as generally relied upon in the utility sector, thereby often forcing an exhumed correction of slugs if they are permitted to occur at inaccessible connections under slabs or in building walls. The NuFlow system greatly reduces such project risks for the contractor and for property owners and managers.

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