PVC is the material of preference in the water and sewer industry because of its ease of construct-ability, 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:
Coupled with PVC's exceptional abrasion and chemical resistance, Ultraliner PVC Alloy is truly an ideal pipeliner material.
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.
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.
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 mechanical 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.
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.
Installation Question 1: "Can Ultraliner PVC Alloy Pipeliner be installed under extreme environmental conditions such as wet weather, extreme heat, and frigid cold?"
The ability to install Ultraliner PVC Alloy Pipeliner under extreme weather conditions enables our licensed installers to be there when you need us. Costly project delays can often be avoided and crews can remain active for more months of the year. Extreme cold, hot, or wet weather may slow our crews down, but it rarely prevents timely completion of a project.
Ultraliner PVC Alloy Pipeliner's wide thermoforming window often permits our product to be installed under extreme environmental conditions. Our pipeliner has been successfully used in the torrid heat of South Florida to the frigid cold of Alaska. The Ultraliner PVC Alloy Pipeliner installed in Alaska survived the coldest winter in 20 years in which the frost lines dropped below the burial depths of the pipeliner. Ultraliner was successfully installed in North Carolina while completely submersed by a flooding river. Ultraliner was successfully installed less than 6 feet from the Atlantic Ocean during a New Hampshire winter while extremely cold infiltration flowed around the pipeliner. In Colorado, Ultraliner was successfully installed while the ambient temperature was below 0 degrees F!
Pipelining with tight-fitting pipeliners cannot be expected to improve flow capacity by more than 10%; and may not provide any increase in flow capacity at all. Any improvement in flow capacity should most likely be deemed negligible to the design.
However....As a result of cleaning the pipes and relining (which reduces infiltration and controls root intrusion), local available flow capacity is gradually restored as the entire collection system is rehabilitated. As pipe capacity upstream is regained, previously surcharged downstream pipes will have the capacity to accept local infiltration which had previously been unable to enter the full host pipe (often referred to as "potential I&I"). Although flow improvements may not be apparent at the treatment plant until until large portions of the system have been rehabilitated, the improvements will be measurable in line segments. As the system undergoes further rehabilitation, reclaimed flow capacity can become quite dramatic.
In addition to regaining capacity through elimination of extraneous flows, the smooth surface of the Ultraliner PVC Alloy Pipeliner (manning coefficient of 0.009) may improve flow rates despite the slight decrease in internal diameter. Because of the tight conformance to the shape of the host pipe, the effective manning of the installed pipeliner is likely 0.010. Flow rates are likely to increase by a negligible amount, so significant flow capacity increases [independent from the reduction of I&I] should not be expected from any tight or close fitting pipeliner.
If significantly increased flow capacity is a greater priority than avoidance of digging and disrupting the surface, then pipebursting procedures [which have the ability to "up-size" and create up to a 150% increase in flow capacity] should be considered.
The conclusion drawn from Uni-Bell's (PVC Marketing Group) extensive research of all published literature on this issue determined that "The appropriate conservative "n" value for minimum slope design of PVC sewer pipe is 0.009, as correctly justified by actual test data."
When Ultraliner PVC Alloy Pipeliner is tightly expanded against the host pipe, the heat combined with the radial stretching of the material will reset the memory of the pipeliner to its newly thermoformed size and conformation. To avoid the radial shrinkage caused by the coefficient of thermal expansion [CTE], the pipeliner should be cooled using an aftercooler to bring the temperature down to at least 90 degrees F or within 10 degrees of ambient while the pipeliner is under internal pressure. Under an installation process developed with an understanding of PVC material behaviors, a properly installed Ultraliner PVC Alloy Pipeliner will have no tendency to radially shrink and will maintain a tight fit.
The typical annular gap of a properly installed PVC pipeliner is approximately the thickness of a business card. A properly installed PVC pipeliner will fit at least as tightly as all other tight-fitting pipeliners on the market. In fact, upon direct inspection of an excavated section of Ultraliner PVC Alloy Pipeliner, the chief inspector of Nashville, TN stated that the pipeliner was "the tightest-fitting pipeliner they had ever used.
Ultraliner PVC Alloy Pipeliner has successfully (and rather routinely) been lined through a variety of bends. In North Carolina, Ultraliner PVC Alloy Pipeliner was used to successfully line 450' of 16" steel pipe with 8 - 45 degree bends in it. It has also been used to line several 6" 90 degree bends for the Washington Suburban Sanitary Commission (WSSC). Additionally, Ultraliner PVC Alloy Pipeliner has been used to structurally stabilize pipes with severe bends caused by off-set and displaced joints which were the result of ground movement.
The exceptional expandability of the PVC Alloy material uniquely enables Ultraliner PVC Alloy Pipeliner to accommodate such diameter restricting bends without the folding of excess material or vertical buckling. The pipeliner is extruded smaller than the most restrictive point in the pipe to be lined and allowed to expand to conform to the changing diameters within the host pipe.
Ultraliner is the preferred product for lining extremely deteriorated and structurally distressed pipes.
Because Ultraliner PVC Alloy Pipeliner is pulled into place, contact with the crown of a crushed pipe is avoided during insertion. By avoiding 360 degree contact with the structurally distressed host pipe, the risk of causing a collapse during insertion is greatly reduced. Ultraliner supports the full length of the host pipe during pressurization, thereby avoiding the risk of collapsing a structurally compromised host pipe in front of an inversion head.
Ultraliner PVC Alloy Pipeliner provides full structural integrity independent of the load-bearing capacity of the existing host pipe. Ultraliner offers 2 varieties of pipeliner (ASTM 1871 and ASTM 1504) enabling the project engineer to select the most suitable product for a particular application. The ductility, toughness, and flexibility of Ultraliner PVC Alloy Pipeliner provide a strength which surpasses mere stiffness.
Knowing that problems will occasionally arise with even the best products and contractors, the question becomes "what happens when...?" Will the product manufacturer and the contractor be able to work together with the customer to ensure a win-win-win resolution to the problem?
One of the primary goals of trenchless pipe rehabilitation (in addition to structural renewal, infiltration control, and cost-savings) is to avoid community disruption. One must consider what the alternatives will be if a trenchless pipeliner installation is unsuccessful. If a disruption of some type occurs, how can the pipeliner be repaired or replaced? Considering the cost disparity between a trenchless installation and an open cut trench replacement, what is the financial risk which must be absorbed by the contractor if the installation is unsuccessful?
With thermoplastic Fold & Form pipeliners (Ultraliner), such risks are greatly reduced. The design properties are established prior to installation. The installation process cannot influence the design properties; they are established and confirmed at the manufacturing facility. When necessary, sectional repairs can be used to correct localized defects, such as a misplaced service connection reinstatement. Given no other option, a PVC pipeliner can be heated and speechlessly removed often in one solid piece, unless the host pipe is in eminent danger of collapse. Such alternatives are much less costly and disruptive to the contractors and to their customers than digging up a pipeliner and removing it "bucket by bucket."
It is up to the owner / project engineer team to determine which products and contractors should be included within project specifications in order to ensure that the needs of the end-user will be met. While suitability to need is more important than cost, once products and their contractors have been approved to bid, the determining factor primarily becomes cost-competitiveness.
Ultraliner is generally very cost-competitive against all of our trenchless rehabilitation competitors, and our cost-competitiveness further increases:
The crews of our licensed installers receive extensive training and support from Hydroliner's Field Service Representatives, who are available for consultation and technical assistance. When Hydroliner signs on a new licensee, key personnel from the newly licensed construction firm come to our corporate headquarters in Anniston, Alabama for in-depth training regarding the installation of Ultraliner PVC Alloy Pipeliner. As a vital part of this extensive training, new licensees work closely with our Field Service Crew using our training equipment to install pipeliners.
Upon returning, the trained personnel are able to draw upon their experience using our training equipment, combined with their own years of construction expertise, to determine the best configuration for their own installation equipment. We also encourage our network of licensed installers to communicate with and learn from one another.
Once the new licensee's equipment has been prepared for use, our Field Service Representatives travel to the territory of the new licensed installer and assist the new crew with installing Ultraliner PVC Alloy Pipeliner using the installer's own equipment. This provides our Field Service Representatives the opportunity to make private suggestions to the management regarding potential improvements to the equipment, in addition to addressing other issues which could enhance the new crew's productivity. Once the Hydroliner Field Service Manager and the new Licensee are both satisfied with the proficiency of the new equipment and crew, the required training is completed and the new Licensee is approved for independent installations.
After training is completed, our Field Service Representatives continue to be available for consultation and technical assistance to both the licensees and their customers. Our Field Service Representatives maintain their own proficiency and gain further experience between training sessions by installing pipe in towns and cities in close proximity to the Hydroliner's corporate headquarters.
Hydroliner also has a Project Manager/Estimator with over 20 years of pipe rehabilitation experience available for additional training and consultation. His insights and advice are available to help experienced general construction managers quickly learn the intricacies of being competitive in the pipe rehabilitation market. Sales and engineering support are also provided to the contractor and their customers.