Small Diameter Pipe Lining

Nu Flow's Small Diameter Re-Line System can be used to repair pipe networks inside buildings. By using Nu Flow's tools, it is possible to line complete systems from the 75 or 100mm diameter stack/soil vent pipe through to the 25mm branch lines serving individual sanitary fittings and domestic equipment.

Change in Diameter Pipe Lining

Using the Nu Flow system it is possible to transition from 100mm diameter through to 150mm diameter pipes using a single sleeve and in one operation. Our patented expandable material gives installers the ability to change diameter anywhere in the pipeline. This change of diameter sleeve enables a full strength liner to be installed in both sizes without compromising the structural integrity of the pipe.

Nu Flow Liners

Nu Flow has engineered liner solutions for straight pipelines as well as those with multiple bends and elbows. Both of these systems are available for lining large and smaller diameter pipe networks. Between these two technologies, Nu Flow can offer complete no-dig remediation of damaged or failed pipelines through existing cleanouts.

Nu Flow technologies can be used on a range of pipe materials including cast iron, concrete, clay, steel, unplasticised PVC and orangeburg. The liner seals fully to the host pipe thus leaving no annular space.

In addition, the system can be used in highly corrosive environments, around 90° bends and to span voids in the pipe sections. The liner material is not subject to the effects of creep or shrinkage and will, therefore, not suffer the same degrading effects as the original pipeline.

Due to dimensional flexibility in the liner material it is possible to transition between pipe diameters without changing the liner. Transitions from 75mm to 100mm and from 100mm to 150mm diameter can be achieved without changing liners.

The Cured-In-Place Technology

Millions of linear metres of cured-in-place materials have been installed worldwide. They have been used in highly corrosive environments and have withstood the test of time. This technology has saved billions of US dollars because it has enabled remediation of pipelines without excavation.

Cured in place materials mold to the host pipe whilst only reducing the internal diameter by a small percentage. This seamless pipe prevents infiltration and exfiltration, restores structural integrity and eliminates joints that can weaken over time and allow root intrusion. Cured in place pipe lining increases flow capacity because it is smoother than the original pipe material and, therefore, has a lower friction coefficient. As there is no need to excavate the pipeline the works can be undertaken with minimal inconvenience to pedestrians and vehicles and without the need to reinstate surface finishes and landscaping.

Nu Flow has the experience, technical knowledge and ability to specify the liner thickness and resin type to meet your specific needs, regardless of pipe depth or corrosive environment. Resin formulas are custom specified to meet individual circumstances and the overall structural strength of the rehabilitated system is benchmarked against ASTM D790.

Cured in place materials mold to the host pipe. This seamless pipe prevents infiltration and exfiltration, restores structural integrity, eliminates joints that can weaken and allow root intrusion. Cured in place pipe actually increases flow capacity because the Nu Flow pipe is much smoother than old clay and concrete pipe. Above ground there are no piles of excavated dirt, no traffic tie-ups, no subcontractors and a happy customer.

Nu Flow Technology has the experience and technical knowledge to specify the right thickness and right resins to meet your specific needs regardless how deep the pipe or how corrosive the environment.

Overview

The main alternative to traditional sewer replacement (which required trench excavation) is cured-in-place lining, sometimes referred to as "soft lining" or "CIPP", which has dominated the non-man-entry sewer renovation market in many countries for over twenty years. For brevity, published guidelines refer to all cured-in-place lining techniques as CIPP systems, although it should be noted that not all providers of such systems use this term.

Several competitive systems are now available. All of these share a common feature - the use of a fabric tube impregnated with polyester or epoxy resin. This tube is inserted into the existing pipeline and inflated against the pipe wall and then cured either at ambient temperature or by re-circulating hot water or steam. Some variations use ultra-violet light to cure the resin.

CIPP systems create a close-fit 'pipe-within-a-pipe' which has quantifiable structural strength and can be designed to suit various loading conditions. The ring-stiffness of the liner is enhanced by the restraint provided by the host pipe and the surrounding ground, but systems designed specifically for gravity pipelines do not need to rely on a bond between the liner and the existing pipe as they are inherently strong. Systems that rely on the host pipe for some measure of structural support are sometimes known as "interactive lining" techniques.

As well as minimizing internal diameter reduction, an inherent advantage of cured-in-place liners is their ability to conform to almost any shape of pipe, making them suitable for relining non-circular cross-sections. Provided that the liner perimeter has been correctly measured and that the dimensional proportions of the existing pipe material are stable until the liner has cured, a close-fitting repair will be achieved.

Laterals connecting to the pipeline that has been remediated can be re-opened remotely after lining using specialised in-line cutting equipment. It is important that the system is installed by suitably qualified technicians as care must be taken during installation to ensure that surplus resin does not enter branches and cause an obstruction. The CIPP system can also be used for lining laterals from within the main pipe.

Design & Specification

Liner specifications and design procedures vary from country to country and are subject to periodic amendment, it is outside the scope of these Guidelines to include reference to all National Standards.

In countries where established local guidelines are not available, a widely-used standard is the Specification for Renovation of Gravity Sewers by Lining with Cured-in-Place Pipes contained in WIS 4-34-04, March 1995: Issue 2, published by WRc in the UK. Design procedures for determining the required wall thickness of circular and non-circular sections under different loading conditions are given in the WRc Sewerage Rehabilitation Manual.

Specifications for pressure (gas and water) applications are laid down by the relevant utility companies and approvals bodies. Most countries have strict requirements and accreditation procedures for all materials likely to come into contact with potable water.

 

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