Question: " What does "PVC Alloy" mean? "
PVC is the material of preference in the water and sewer industry because of its ease of constructability, simplicity of maintenance, and unrivaled durability. For trenchless relining, however, a more ductile PVC compound is required to allow the Fold & Form aspect of insertion into a host pipe. The compound must resist cracking and splitting of the pipeliner during the installation process. Ultraliner along with chemical engineers at Dupont and Vista Chemical developed a new class of PVC compound for use in trenchless pipe rehabilitation applications which we refer to as a PVC Alloy.
The unique PVC Alloy material is composed of PVC homopolymer integrally blended with special modifiers. This compound is extremely tough, durable, and especially suited to trenchless applications. Some other unique characteristics:
extremely high impact strengths, wide forming temperature range,
high degree of dimensional stability, and ability to relieve high levels of stress
without structurally compromising the material.
Coupled with PVC's exceptional abrasion and chemical resistance, Ultraliner PVC Alloy is truly an ideal pipeliner material.
Question: " How is quality assured with Ultraliner PVC Alloy Pipeliner? "
The design values (wall thickness, chemical resistance, and material strengths) of Ultraliner PVC Alloy Pipeliner are established at the manufacturing facility under controlled, ASTM prescribed conditions. This gives a level of quality control which is unsurpassed in the industry. Because PVC pipeliners are not dependent upon field conditions for their final design properties, laboratory prepared test samples of PVC pipeliners will be consistently representative of the actual field installations. ASTM D-1784 is the PVC Compound Product Specification.
Field installation factors (temperature, groundwater, etc.) during the relining process have a negligible influence upon the design properties (material modulus, wall thickness, chemical resistance, etc.) of Ultraliner PVC Alloy Pipeliners. As a result, the design properties will be consistent throughout the project.
Question: " Does Ultraliner PVC Alloy Pipeliner have chemical resistance comparable to standard PVC pipe? ”
Ultraliner exhibits exceptional chemical resistance properties and does not degrade in typical sewage applications. The chemical resistance of Ultraliner PVC Alloy is essentially the same as standard PVC pipe in both acidic and basic environments.
PVC pipeliners are homogenous, solid wall pipes and, therefore, have equivalent chemical resistance down their entire length, including at the service cuts.
For sewage applications, Ultraliner PVC Alloy Pipeliner's chemical resistance is comparable to that of HDPE materials and far exceeds that of the CIP materials.
Question: " What is the expected design life of Ultraliner PVC Alloy Pipeliner? "
PVC is known for its durability in water and sewer applications, and Ultraliner PVC Alloy Pipeliner is no exception. The innate flexibility of PVC provides much greater strength in a buried installation than mere material properties would suggest. The resistance to the fluids being conveyed and the mechaical properties engineered into Ultraliner provide long-term structural stability in trenchless pipe rehabilitation applications. With appropriately conservative design, Ultraliner PVC Alloy Pipeliners are expected to far exceed a 50 year design life.
Question: " What is the value of wall thickness? "
Greater wall thickness is particularly valuable in relation to the ring stability of a pipeliner when subjected to extreme groundwater pressure. A thicker wall also decreases the relative influence of imperfections in the host pipe. Despite the value of wall thickness, it can complicate constructability of both thermoformed (fold & form) and thermocured (CIPP) pipeliners. The thicker the wall the more difficult it becomes to properly heat the pipeliner.
Despite the value of wall thickness, a balance must be struck in regards to constructability. The thicker the pipeliner the more difficult it becomes to adequately heat and successfully thermoform a Fold & Form pipeliner.
The best design is a balanced design; where structural requirements are met and extra conservatism minimizes the effects of uncontrolled variables (construction influenced). For Fold & Form pipeliners, excess wall thickness may hinder installation rather than provide added conservatism. Typical design is to provide a liner diameter approximately 10% smaller than the final “expanded” size and at a thickness to provide the final design or desired wall thickness (e.g. SDR 35). The proper selection of compound variables must be considered for each application.