Rehabilitating aging pipes and utility systems poses significant challenges, but the right liner can make all the difference. Ultraviolet light-cured, glass-reinforced pipe (UV GRP) is an industry-leading option with proven durability, efficiency, and cost-effectiveness. But with multiple types of UV GRP liners available, identifying the best fit for the job at hand can be difficult.

From understanding the liner types and compliance issues to evaluating the return on investment and ensuring environmental sustainability, numerous considerations factor into choosing a UV GRP solution. This guide will help you navigate the selection process to achieve success with your next infrastructure rehabilitation project.

Understanding UV GRP Liners

Instead of using traditional curing methods like steam or hot water, a UV GRP liner is resin-impregnated fiberglass that’s cured rapidly with ultraviolet light. Typically, UV lamps are placed inside the liner. When activated, they emit UV light that cures the resin, hardening it to create a strong, watertight pipe within the existing pipe.

The advantages of UV GRP liners include faster installation times, reduced environmental impact, and the ability to control and log each aspect of the curing process. These liners are commonly employed in sewer and wastewater pipeline rehabilitation and can be installed in circular, ovoid, arch, and rectangular-shaped pipes.

The stronger and thinner liners also provide a higher hydraulic capacity for the systems being repaired. For instance, the flexural modulus of Reline America’s Alphaliner ranges from 1.66 million psi to 3 million psi, which is among the highest in the industry.

Consider Your Options

Distinguishing the different types of UV GRP liners empowers asset owners to choose the most suitable liner based on the intricacies of the project. The options include continuous, sectional, and custom UV GRP liners.

Continuous Liners

Reline America’s Alphaliner is an example of a continuous UV GRP liner. It is manufactured in a spirally wound process to create a seamless and tight-fitting liner. Once the existing pipeline is inspected to assess its condition and confirm it’s suitable for cured-in-place-pipe (CIPP) lining, the saturated liner is inserted into the pipeline through an access point — often a manhole or inlet. The calibration tube or bladder inside the liner is then flattened, pushing the liner against the inner walls of the existing pipe to form a tight fit. Next, a UV light source is inserted into the liner to cure the resin while the critical parameters are monitored. Finally, the cured liner is inspected for quality, ensuring it is watertight and structurally sound.

Sectional Liners

Sectional UV GRP liners are used when the asset owner does not want to line the entire length of the pipe (manhole to manhole). They are assembled within the host pipe using smaller, manageable sections. Each section features a UV-curable resin and is installed piece by piece. This approach allows for easier handling and installation, making it practical to control more centralized issues, such as leaking joins, cracks, and seal holes or gaps.

Custom Liners

Custom UV GRP liners, like Alphaliner, are designed and manufactured to specific criteria for each pipe segment. They are not premade or sitting on a shelf ready to ship. To determine the correct wall thickness for each liner, the manufacturer must receive detailed information on the host pipe material, condition of the host pipe, inside diameter of the host pipe, ovality of the host pipe, design safety factor, unit weight of soil, depth of cover, specified constrained soil modulus, height of groundwater, surface live-loading condition, and pavement type.

The benefits of custom liners include knowing you are getting a proper fit for each line you are rehabilitating. Each line or segment will have a premanufactured and cut liner delivered to the contractor, allowing them to move faster and more accurately through the project with no guessing on the job site. Custom liners can also be manufactured to fit circular, ovoid, arch, and rectangular shapes.

Assessing Project Requirements

When striving to identify the best UV GRP liner, first consider the project’s parameters and specific issues within the failing infrastructure. Once these issues are understood, the best repair method can be selected. Critical considerations for selecting the right lining method include the pipe diameter, material compatibility, accessibility, environmental impact, and budget.

Next, assess the compatibility and compliance of a UV GRP liner application, such as meeting NSF/ANSI Standard 61 for potable water applications. Making thoughtful evaluations against these parameters can lead to more effective (and sustainable) infrastructure rejuvenation.

Solving Your Infrastructure Requirements

Choosing the appropriate UV GRP liner is crucial to addressing the challenges of aging infrastructure — and ensuring the long-term success of rehabilitation projects. By understanding the types of UV GRP liners and prioritizing compliance and quality, engineers, municipalities, and other stakeholders can make well-informed decisions about how to apply the liners to the best effect.

Currently, Reline America is the only manufacturer in the United States that produces its own liner and curing equipment for optimized performance. As a one-stop shop for liners and equipment, the company can provide the proper liner for the job regardless of the host pipe’s profile. Its Alphaliner is manufactured to meet or exceed all current ASTM standards for UV GRP CIPP lining and features a versatile installation method, making it the right choice for most pipeline rehabilitation needs.

To learn more about best-in-class UV GRP Liner solutions, visit