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BulletLiner System® FFRP for Pressure Pipe Rehabilitation
Trenchless methods have been widely used for the rehabilitation of gravity pipelines for over 40 years. The advent of these technologies and methods has lowered the cost of extending the useful life of gravity pipelines through rehabilitation versus outright replacing them. In addition, the significant increase in value-added products on the market has created competition resulting in further technology development and cost reduction for extending the service life of critical assets. Due to the means of execution, trenchless rehabilitation methods are ecologically and socially friendly when compared to traditional open cut pipe replacement.
For these reasons, trenchless technologies for rehabilitation continue to grow and evolve in the pressure pipe sector with immense benefits to the end-user. Shorter downtimes, less disruption to the environment, less economic impact to businesses and surrounding communities are readily observable effects of the development and improvement of trenchless technologies for pressurized water and wastewater pipelines. Perhaps most importantly, these variables have a considerable impact on the bottom line, cost.
Flexible Fabric Reinforced Pipe (FFRP)
FFRP has been successfully utilized in the United States for over ten years, but on the timeline of trenchless technology it is still considered to be in its infancy. There are currently two types of FFRP approved for use in the United States and both are considered AWWA Class III liners (self supporting and independent of the host pipe). At a glance, the two available liners share many common traits both in material properties and installation method. Both options, in their standard form, consist of three layers: 1. A modified, abrasion resistant polyethylene outer; 2. An inner fabric layer that provides the tensile strength and pressure capabilities; and 3. A polyethylene inner layer with a C-Factor of 150. Both products are ideally suited for pressure pipe rehabilitation applications. Each FFRP option has a modified abrasion resistance polyethylene (PE) outer layer, a middle layer of fabric reinforcement (including options such as seamless woven polyester, aramid, or a combination of the two fabrics), and a modified PE layer on the inside (providing the necessary flexibility to allow the liner to be folded and re-rounded when installed). FFRP is an excellent solution for a wide variety of applications, especially those in which traditional open cut is challenged by above ground infrastructure, where CIPP is challenged by geometry, and where sliplining reduces the finished inside diameter reducing capacity. Other benefits of each product include rapid installation times, long pull distances, small termination portals, small overall project footprint, NSF 61 certification for potable water, and installation regardless of ambient factors as no curing or bonding is required.
The manufacturing process, available diameters, and termination fittings are the primary differentiators between the two currently available products. One option is analogous to loose-fit sliplining in that it does not fit snug against the inside diameter of the host pipe. This product is manufactured utilizing a process called co-extrusion. The maximum size available utilizing this type of co-extrusion process is currently 20-inch nominal, which leaves the existing host pipe with a final finished inside diameter of 17.2-inch. The manufacturing process is the primary differentiator between the two products that are currently available: BulletLiner System® extrudes the jacket and liner through the woven fabric layers, resulting in greater tensile strength and adhesion, which allows the manufacturing and installation of sizes currently up to 48-inch. Both systems have a high friction coefficient of 150 and are considered a Class III pipe rehabilitation system based on the current AWWA classifications.
Pull lengths are generally dictated by appurtenances, pulling equipment capacity, cleaning capabilities, material properties of the fabric reinforcement, and the type of pulling device used. Distances are capable up to 13,000 linear feet with the BulletLiner System® that extrudes the liner and jacket through the weave and is monolithic using specific pulling devices which take advantage of the finished product’s high tensile strength. The difference in maximum pull capacities are a result of the difference in the manufacturing process of the liners, material properties, and pulling devices and equipment used.
Termination fittings are also very different from the two different available systems. The BulletLiner System® utilizes a two piece fitting system that matches the liner internal diameter and in turn maximizes flow through the finished system and minimizes pressure loss across the fitting system.
Another consideration when planning pull distances are the spools used to transport and store the liners for installation. Larger pipe diameters can fit smaller lengths of pipe on the transporting spools to remain maneuverable and remain below the limits of container shipment capacities. FFRP is manufactured round then flattened, folded, and taped for transportation to the jobsite, providing ease of insertion into the host pipe. After insertion, air is introduced into the liner to restore it back to its fully round shape.
Benefits to FFRP
- Long segments can be pulled at once and result in zero joints.
- Quick installation when compared to dig and replace, and other trenchless methods.
- Liners easily navigate 45-degree elbows wrinkle-free.
- Can be used on all types of pipe materials.
- Installation is not dependent on weather conditions, and curing is not necessary.
- Minimal diameter reduction (embedded liner even more so), with diameters available from 2-inch to 48-inch.
- Requires minimal planning and calculations, with a small construction footprint.
- Independent operating pressure ratings up to 305psi, based on standard design criteria that can be customized based on application
- Higher pressure capabilities when the liners are used interactively with the host pipe
- Provides a 50+ year design life.
Trenchless technologies for pressure pipes continue to be favored over dig and replace methods. BulletLiner System® can re-establish the original life of the pipe, is cost effective, and ecologically and socially responsible. FFRP technology has unique advantages and benefits that fit many situations better than other rehabilitation or replacement options. Considerations that an asset owner must evaluate when considering rehabilitation with BulletLiner System® include capacity requirements, pressure needs, pipe classification, host pipe alignment and features, existing utilities, and social and environmental impacts.
If you are considering a trenchless technology as a method of re-establishing the useful life of a deteriorating pipeline, contact CPM Pipelines to learn about our proprietary BulletLiner System®.