National Liner uses quality liners manufactured by Applied Felts, because they partner with us to address the unique requirements of each National Liner CIPP job. As the world’s largest independent manufacturer of 100% vertically integrated felt liners, Applied Felts is accredited ISO 9001:2008 and every phase of manufacturing – including a 28-stage testing system – is done in one location.
First, raw materials such as polyester fibers, polyurethane granules and other materials are tested for quality. Next, during the five-stage felt production process, a number of criteria including density, thickness, fiber distribution evenness, strength and weld-ability of the finished felt are tested. Applied Felts utilizes a “single pass” extruded process for the coating of the felt to ensure that no pinholes are present. During this phase, four separate tests are conducted to monitor coating uniformity, mass and weight distribution.
Once the felt has been coated, each roll is sampled and destructively tested across a total of nine quality characteristics, including density at various pressures, tensile strength, coating distribution and more. During production, the testing doesn’t end. The liners are continually checked to ensure they satisfy the specifications of your order.
Finally, when the project is complete, a sample is cut from each finished liner and is tested across yet another seven criteria to make sure the circumference, density, length, coating integrity, weld strengths and other properties meet and exceed your exacting requirements.