Envirocort Technologies

Envirocort Technologies

- Structural Lining System


Poly-Triplex is the industry’s leading product for permanent rehabilitation of structures in sewer collection systems that are failing due to chemical corrosion and infiltration of groundwater. These conditions result in structural fatigue, roadbed degradation, expensive costs for unnecessary treatment of groundwater, overload of the wastewater treatment plants and pollution into our environment. Envirocort has focused on engineering products that are quick to install and provide permanent and effective solutions for sewer manhole, pump station and culvert rehabilitation.

The patented Poly‐Triplex structural lining system, a Cured-in-Place product that is quality constructed with three‐layered fiberglass and an epoxy system that contains a vital, non‐porous internal membrane, is the best solution for failing structures. The process uses the existing structure as a mold, enabling installation without the need for excavation and prolonged sewage flow and traffic disruption.

Once saturated with resin at the jobsite, the liner is lowered into the structure and cured using air pressure and steam. This forms a composite structural liner that is bonded to the host structure and pressurized into a compressive fit. The epoxy resin bond further enhances the structural capabilities of the Poly‐Triplex lining system, and the non‐porous membrane, encapsulated in the center of the composite, provides a barrier to chemical attack as well as a permanent barrier to prevent groundwater infiltration into the collection system.


Cured in Place Structural Liner Components
Poly-Triplex Liner design uses three layers of structural materials that are comprised of five separate components.

Layer #1 – Structural Fiberglass
This component is saturated with 100% solids epoxy resin and bonds to the host structure.

Layer #2 – Non-Porous Inner Membrane
This layer contains 3 critical components, one non-porous membrane with felt fibers embedded on both sides, creating a mechanical bonded between the membrane and the other materials. This layer is the most vital part of the rehabilitation process, eliminating any pinholes, thereby providing a permanent barrier to infiltration, ex-filtration and gas penetration.

Layer #3 – Structural Fiberglass
This component is saturated with epoxy resins and once cured, provides protection to the internal non-porous membrane and provides a smooth interior surface to the lined structure.

Poly‐Triplex liner systems are firmly established as the premier product line for the reconstruction of manholes and other underground structures owned by public utilities and private industry. Each liner is designed and manufactured to the dimensions required by the end user. Overseeing and providing all Quality Assurance needs, Envirocort Technologies distinguishes its products by the following markets and capabilities:


  • Manholes (all sizes, shapes and material)
  • Sewer Wet Wells/Lift Stations
  • Wastewater Treatment Plant Structures
  • Large Diameter Pipes


  • Manholes
  • Vaults
  • Large Diameter Pipes


  • Manholes
  • Catch Basins
  • Large Diameter Piping

Process Overview
The Poly-Triplex installation process is like none other you'll find in the industry. Using the existing structure as a mold, we can complete the installation without the need for excavation and disruption, in 4-6 hours for most cases. The liners are fabricated and resins are blended in our 23,000 square foot manufacturing facility. Our liners consist of three primary layers and they are custom fabricated to fit each structure. The three layers include: one non-permeable inner membrane embedded on both sides with special polyester fibers, layered between two layers of structural fiberglass saturated with epoxy resin. The liners are engineered in several standard liner weights to address varying structural conditions within the structures. The custom manufactured liners are cured-in-place with a patented system of air pressure and steam.

Each custom manufactured Poly-Triplex liner is saturated at the jobsite with a two-part epoxy resin system that will bond to wet or dry surfaces. The liner is then lowered into place with a crane or lifting device. The Poly-Triplex liner is aligned so that it will contour to the shape of the host structure.

The liner is typically cured by applying approximately 500-1,000 pounds per square foot of pressure with the injection of steam set at approximately 300 degrees. This causes the removable inflation bladder to fully expand, forcing the liner to conform to the contours of the structure surface, stopping all active infiltration. In certain cases where the typical method of installation is not appropriate, the Poly-Triplex system may be cured in an ambient temperature environment or under hydrostatic pressure.

Manhole and catch basin installations typically take four to six hours to complete. Depending on site & structure size, conditions and location, one three-man installation crew can line two structures per day with one installation truck.

After curing is complete, the bladder is removed, leaving the laminated composite liner system that is fully bonded to the existing structure, permanently stopping further deterioration, infiltration and ex-filtration.

After the bladder is removed, pipes are reopened with a reciprocal saw or offset grinder. The sub-floor is removed and the liner is trimmed at the invert channel. In this particular case, as photo above shows, the sewage has continued to flow throughout the entire lining process with no disruption.

Pump Station and wet well installations are primarily the same as for manholes. Structure is empty and free of all mechanicals and cleaned with high pressure hydro-blasting with a rotating pencil tipped nozzle. The liner's bottom disk section is saturated and positioned on the floor and approximately 6 inches up the wall. The liner is then saturated and lowered into the structure with the wall section overlapping the floor section a total of approximately 12 inches. Liner is typically cured in place under air pressure. Steam heat is injected to expedite the curing process. Rectangular structures may be lined using Poly-Triplex overlapping panels and cured as a monolithic structure. Pump Station rehabilitation usually can be completed within a 12-24 hour period, significantly minimizing bypass pumping operations.

Culvert and large diameter pipe lining is completed using a pull-through method of installation. Liner is saturated at the jobsite with an appropriate resin system. Liner and inflation bladder are typically encapsulated inside a durable reinforced vinyl skin, and then pulled through using a winch and cable system. Liner is then inflated and pressurized into place. Water and steam are injected facilitate the curing process. Once cured, the bladder is removed and structure is completely lined from end to end. In the case of longer runs, the liner may be installed in two or more overlapping sections. Typical culverts can be completed usually within a 12-24 hour period, with little or no disruption of highway traffic.


How does Poly-Triplex compare with other types of rehabilitation methods?

Spray Applied Epoxy:
Applied properly spray-on epoxy coating can provide some protection from chemical corrosion. However, epoxy spray coatings require that all active infiltration is stopped with concrete patching or chemical grout injection and the host structure must be completely dried before application. The heat generated during the epoxy curing process causes air bubbles behind the coating to expand and rupture, leaving microscopic pinholes in the epoxy coating. Sewer gasses are able to seep through and lead to failure of the epoxy coating and deterioration in the surface wall as shown in the photo above. Also thickness of the coating is determined by the discretion of applicator at the jobsite.

The Poly-Triplex system may be installed in structures with active infiltration and the inner membrane provides a non-porous, gas impermeable barrier protecting the structure from future chemical attack. Liner thickness is determined and controlled at the manufacturing facility, not left to chance with the applicator at the jobsite.

Polyurethane coatings:
Polyurethane is very chemical resistant. However, the coating requires that all active infiltration is stopped with concrete patching or chemical grout injection and the host structure must be completely dry before application. During the drying process, the polyurethane coating shrinks and becomes hollow as is pulls off the structure and in essence, “masking” the problem of future infiltration that will run down behind the material undetected and leaking into the structure where the coating ends. Infiltration and deterioration is inevitable.

The Poly-Triplex system bonds to the surface of the host structure. The curing process is done under air pressure, so the resins are literally pressed into the surface, cracks and crevices of the structure, providing a chemical and mechanical bond between the liner materials and the wall. No infiltration can leak between the liner and the wall.

Spray applied cement coatings:
Cement Coatings do provide structural enhancement to the structure, but do not solve the problem of active infiltration because the host structure typically will have stress cracks and will re-crack again in the cement coating. These coatings are also still subject to future chemical attack as was the original structure.

The Poly-Triplex system will structurally rehabilitate the structure with more than XX0000 psi of flexural strength as well as provide a surface that is non-porous and chemical resistant to protect the structure from future infiltration and corrosion.


Fiberglass or hand layup systems:
Fiberglass bag liners that do not contain the internal non-porous membrane and fiberglass/epoxy coatings that are applied by hand layup method do provide some structural enhancement of the structure. However, the liner or coating also has pinholes between the fiberglass strands allowing infiltration to seep through the liner and chemical penetration to continue attack on the host structure. In the photo above chemical grout has been injected behind the liner revealing pinholes in the liner. These pinholes will lead to chemical attack of the host structure and eventual failure of the rehabilitation effort.

The Poly-Triplex system contains the fiberglass layers but with the addition of the non-porous inner membrane that eliminates any pinholes and provides a barrier to infiltration and further chemical corrosion.

The patented Poly-Triplex Liner is a multi-layered custom fabricated Liner that consists of felt, fiberglass and an impermeable inner membrane that is protected between two layers of epoxy saturated fiberglass. 100% solids epoxy is used to wet out the Liner. The Poly-Triplex Liner eliminates inflow and infiltration, provides corrosion resistance for the original substrate, and structurally enhances the manhole.

For manholes, wet wells, pump stations, and other underground structures that require rehabilitation due to inflow and infiltration, corrosion, and structural degradation.

The Part A Resin is white; the Part B Curing Agent is dark brown. When mixed the product is tan.

A wide variety of Liner models are available.
Liner thickness varies depending upon the number of layers of fiberglass and the weight of the fiberglass used. Liners can range from
100mils to 250mils. The minimum Liner thickness is determined by a formula based on bonding to the substrate. Design methodology and calculations are available upon request.

The substrate must be prepared to provide a clean surface. The substrate must be free of dirt, debris, oil, grease, rust, scale or deposits. A Concrete Surface Profile of 3 or greater is desired. All leaks must be stopped. All steps and other protrusions must be removed. Recommended PH of substrateis 4 to 10. Temperature range of substrate should be 40°F to 120°F.

The Liner can be wet out in the field or at a wet out facility. The Liner is lowered into the manhole and aligned properly. Air pressure is used to inflate a bladder inside of the Liner. The Liner is inflated to press against the walls of the structure. Inflation pressures can range from ¼ psi to 8 psi. The Liner is then cured with hot water, steam or ambiently. Curing takes about an hour using steam. After curing all of the pipes are cut out and the Liner is cut off at the frame where the cover rests.

To clean tools, use acetone, MEK or xylene. To clean skin, wash immediately and thoroughly with soap and water. Refer to the Material
Safety Data Sheet for additional information on health and safety.

The pot life is 20 minutes for one gallon at 72°F.
Longer pot life is possible by mixing cooling the resin.

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