Sewer renewal specifications are shifting. Engineers are looking for liner systems that cure faster, produce fewer emissions on site, and deliver stronger structural performance per millimetre of wall thickness. UV-cured glass fibre CIPP addresses all three demands in a single product. Insituform manufactures iPlus Glass as part of its CIPP solutions range, engineered specifically for gravity sewer rehabilitation where speed, structural performance, and environmental impact all sit on the specification checklist.
Understanding how UV CIPP works at a product level helps engineers write a tighter specification and choose the right system for the pipeline conditions they are dealing with.
How Does UV CIPP Lining Work with iPlus Glass?
iPlus Glass is a glass fibre reinforced tube that is pulled into the host pipe and cured in place using ultraviolet light. The curing process hardens the resin within the glass fibre matrix, forming a jointless, seamless pipe-within-a-pipe that bonds to the existing host.
The glass fibre reinforcement is central to the product’s structural characteristics. Because glass fibre delivers higher flexural strength per unit of wall thickness than standard felt-based carriers, iPlus Glass achieves equivalent or superior structural performance with a thinner tube. That thinner wall means less cross-sectional reduction inside the host pipe, preserving more of the original flow capacity after rehabilitation.
Less resin is required to achieve the target structural properties, which reduces both material weight and the volume of volatile organic compounds released during curing. The liner is delivered impregnated and ready to install, though it can also be supplied dry where the project requires on-site impregnation.
Insituform also supplies the iPlus Glass RF variant, which includes a reinforced outer foil. This removes the need for a separate slide foil on installations up to 400mm diameter, simplifying the contractor’s setup and reducing the number of components required on site.
Where Is UV-Cured Glass Fibre Pipe Lining Best Applied?
iPlus Glass covers a diameter range from 150mm to 1,200mm and accommodates soft bends up to 30 degrees. It is compatible with any host pipe material and handles effluent temperatures up to 75°C within a pH range of approximately 4 to 10, depending on water temperature and the resin system used. Typical shot lengths extend up to 200 metres.
Those application parameters make gravity sewers the primary target, particularly in contexts where the specification demands both structural rehabilitation and minimal disruption. Urban environments, historic town centres, and sites where excavation would close roads, divert traffic, or disrupt commercial activity are strong fits for UV CIPP because the installation footprint is smaller and the cure time is significantly shorter than heat-based alternatives.
Pipelines exposed to elevated effluent temperatures or mildly aggressive chemical conditions also benefit from the combination of glass fibre reinforcement and the resin systems available for iPlus Glass. The product category is gravity only, so pressure applications fall outside its scope and into the InsituMain Pressure range.
The evolution of UV curing within the wider trenchless technology landscape has been driven by exactly these application demands: faster project turnaround, lower on-site emissions, and thinner walls that protect hydraulic capacity.
What Advantages Does UV Cure Offer Over Heat or Steam?
Traditional CIPP curing relies on hot water or steam circulated through the liner to activate and harden the resin. UV curing replaces that thermal process with a UV light train pulled through the liner at a controlled speed. The practical differences on site are significant.
Cure time is shorter. A UV light train can cure a typical installation in a fraction of the time required for a hot water or steam cure cycle, because there is no heating, holding, and cooling sequence to manage. That speed advantage compounds across multi-section rehabilitation programmes where crews move between manholes on a single shift.
The jobsite footprint shrinks. UV cure eliminates the need for boilers, water heating equipment, and the associated hose runs that hot water and steam installations require. Less equipment on site means less road space occupied, less noise generated, and fewer logistics to coordinate.
Environmental performance improves in two ways. The UV curing process itself consumes less energy than heating large volumes of water, cutting carbon dioxide emissions during installation. And because iPlus Glass uses less resin than standard felt-based CIPP to achieve the same structural class, VOC emissions during curing are reduced. Those are measurable differences that increasingly matter in specifications where sustainability criteria carry weight alongside technical performance. The shift toward innovative materials in CIPP is driven partly by these environmental gains.
What Should Engineers Consider When Specifying iPlus Glass?
Specifying UV-cured glass fibre CIPP is a product-level decision, and the manufacturing detail behind the liner matters as much as the installed performance targets.
Wall thickness and structural class should be calculated to recognised international standards and matched to the host pipe’s condition assessment. A fully deteriorated pipe requires the liner to carry all structural loads independently, while a partially deteriorated classification allows a thinner wall. The specifier’s job is to ensure the manufacturer can evidence that the liner, at the diameter and wall thickness being ordered, has been independently tested to the structural class written into the specification.
Flexural strength and modulus of elasticity are the mechanical properties that define how the cured liner will perform under load. Glass fibre reinforcement delivers these properties at a higher ratio to wall thickness than standard CIPP carriers, which is why the product can be thinner without sacrificing structural class. Engineers should request tested values at the specific diameter being specified, not generic product-level averages.
Manufacturing quality control is the final layer. Insituform applies 28 quality control checks to every single CIPP liner manufactured and operates under ISO 9001 certified quality management. For specifying engineers, that traceability means the iPlus Glass liner arriving on site has been produced within a controlled, auditable manufacturing environment, and the documentation to prove it is available on request.
Specifying iPlus Glass for UV Cured Sewer Renewal
iPlus Glass delivers a glass fibre reinforced, UV-cured rehabilitation product that gives engineers a thinner wall, faster cure, and lower emissions within a proven gravity sewer application range. The product is manufactured, quality-controlled, and supplied by the company that invented CIPP in 1971.
We manufacture the full CIPP solutions range at our ISO 9001 certified facility in Wellingborough, supported by over 50 years of CIPP manufacturing expertise. If you are writing iPlus Glass into a sewer renewal specification or evaluating UV-cured lining for an upcoming project, our technical team can advise on product selection, structural class, and project-specific requirements. Get in touch to start the conversation.
