Straight Answers to Frequently Asked Questions About EPI's PVC Geomembranes
Q: What is a geomembrane?
A: A geomembrane liner is a manufactured, low-permeability synthetic membrane used to control the movement of liquids, gases, or contaminants in civil, environmental, and industrial applications. Typically made from engineered polymers such as PVC, POLYPROPYLENE or POLYETHYLENE. Geomembranes act as a critical barrier in systems like water reservoirs, canals, landfills, lagoons, and secondary containment. Their job is simple but non-negotiable: prevent leakage. The complexity lies in how that job is done—material formulation, thickness, flexibility, chemical resistance, seam strength, and installation method all determine long-term performance. When properly designed, fabricated, and installed, a geomembrane liner provides decades of reliable containment, protecting infrastructure, natural resources, and the environment from failure that would otherwise be invisible until it’s catastrophic.. There are a variety of applications and industries that use geomembranes, including the agriculture industry, oilfields, landfills, and more.
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Q: What types of geomembranes are available?
A: EPI offers several types of custom industrial geomembrane liners. Some of our most common liners include:
To request one of our free Product Sample Books, please email your name, phone number, and address to sales@geomembrane.com.
For more information, call 800-OK-LINER today!
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Q: Which geomembrane has the longest historical performance?
A: PVC, by a long shot! Since the 1950s, PVC has been effectively utilized on a wide scale in containment applications. In fact, studies by a United States Government agency on PVC, prove that the physical property retention is in excess of the then current National Sanitation Foundation Standard 54 requirements.
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Q: How do you use geomembranes?
A: Some of the common applications for geomembranes include the following:
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Q: How are geomembranes made?
A: Geomembranes are made from continuous sheets of material that can be as large as your project needs. If you need a liner that connects, the seams are heat-sealed together. The liners can be made from made different materials, depending on the application you need the liner for. At EPI, we pride ourselves on producing the highest quality geomembrane systems available, a prominent aspect of which is quality control.
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Q: What type of quality control standards are in place for EPI's PVC Liners?
A: EPI is dedicated to using only the highest-quality raw materials, which either meet or surpass all standards as determined by the PVC Geomembrane Institute (PGI). EPI is considered the industry leader in creating testing methods using actual factory seam samples, and our "Quality Fabrication Control Manual for PVC" is lauded for its well-researched, detailed, and straightforward technical approach to PVC liners.
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Q: Does EPI test actual factory seams?
A: Yes. Although many companies substantiate only the accuracy of their equipment settings, the team at EPI actually performs destructive seam tests from each and every liner that ships from our facility. To reach the pinnacle of geomembrane performance from the tests, EPI's in-house quality control program uses an independently-designed statistical process control sampling method which guarantees the tighest industry standards.
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Q: Does EPI engage in any performance testing?
A: As pivotal as index testing and fabrication consistency are, actual field performance is the ultimate liner test. For several years, EPI has conducted systematic analysis of liners in the industry's only on-site test ponds. Various seaming techniques in both exposed and buried test plots are subject to a variety of technical performance criteria. In addition, EPI's in-house lab maintains on-going tests in many areas including loading, UV stability, friction characteristics and aquatic research.
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Q: Can EPI air channel test its PVC field seams?
A: EPI has refined thermal welding technology to apply to PVC geomembranes. This state-of-the-art process allows EPI to employ exacting and precise air channel field seam testing. Thermal welding also allows EPI to complete PVC installations in more extreme weather conditions than are practical with traditional chemical fusion methods.
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Q: What size are EPI's panels?
A: At EPI, our liners are often 200 feet wide and we have fabricated one-piece PVC panels of more than one acre in size. In fact, size is generally limited only by what panel weight can be efficiently handled in the field. Regardless of size, at EPI there is never a wide panel "up charge." And, our unique manufacturing process enables us to fabricate irregular shaped panels, reducing overall costs for irregular shaped containments. Our factory fabrication process also reduces field seaming requirements by as much as 80% over some types of liner materials, resulting in significant dollar savings.
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Q: How does installation of EPI's PVC compare with clay or polyethylene liners?
A: Installation is faster and more economical with EPI's PVC.
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Q: What thickness does the EPA recommend for PVC?
A: PVC is designed to provide strength and three-dimensional elongation without requiring the added thickness necessary to accommodate the grinding and welding procedures associated with polyethylene. In fact, recent federal landfill guidelines show that 30 mil PVC, 36 mil CSPE and 60 mil HDPE are functional equivalents.
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Q: Will EPI's PVC stress crack?
A: EPI's PVC has an amorphous structure as opposed to the crystalline structure of polyethylene liners. Therefore, EPI's PVC is not subject to crazing or stress cracking from heating, high thermal expansion, or localized stress concentration geometries which adversely affect polyethylene liners.
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Q: What is Geotextile Sewing?
A: Geotextile sewing is a method for joining geotextiles. Other popular methods include overlapping, stapling, and bonding. Sewing is the method used in situations when a more-substantial seam is required. There are different types of stitches used when sewing geotextiles. The two most commonly used are a simple chain stitch and a modified 401 lock stitch. EPI offers geotextile sewing along with related geosynthetic materials, contact us with any questions regarding geomembranes and geotextile sewing. ​
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Q: How can I order EPI's PVC?
A: Call us today, toll-free, at 800-OK-LINER for the name of the EPI dealer nearest you.
UltraTech Frequently Asked Questions
A. UltraTech® is a polymeric flexible membrane liner formulated using state-of-the-art polymers, resin modifiers, and stabilizers forming a geomembrane with the best combination of physical properties available today.
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Q. Can UltraTech® be left exposed to the sun and elements?
A. UltralTech® has been specifically designed for exposed applications. Its combination of ingredients has been compounded for applications requiring exposed conditions. UltraTech® has been subjected to accelerated testing up to 10,000 hours, assuring retention of physical properties after years of exposure and weathering.
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Q. Is UltraTech® resistant to petroleum products?
A. UltraTech® has been tested with many different petroleum products, including diesel fuel, kerosene, naptha, crude oil, etc., and proven to be very resistant to the migration of these products through the liner.
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Q. Why isn't UltraTech® 60 mils thick?
A. Unlike polyethylene, which is made thicker because of its physical property restrictions, UltraTech® is designed to provide strength and elongation without requiring added thickness to accommodate the grinding and welding procedure required for HPDE. Field performance of UltraTech® is comparable to polyethylene liners of twice the thickness.
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Q. Will UltraTech® stress crack?
A. UltraTech® has an amorphous structure, as opposed to the crystalline structure of polyethylene liners. Therefore, UltraTech® is not subject to crazing or stress cracking from heating, high thermal expansion, or localized stress concentration geometries which adversely affect polyethylene liners.
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Q. Can UltraTech® be used for aquaculture?
A. The UltraTech® formulation is suitable for aquaculture applications. Colors other than black are also available on a special order basis.
Q. What size are UltraTech® panels?
A. UltraTech® can be custom fabricated to your specific job size requirements. Panel sizes are only limited by the weight that can be efficiently handled at the job site. Panels up to 30,000 square feet are available, thereby eliminating up to 70% of field seams. Custom fabricated, irregular shaped panels also save you time and money.
Q. How is UltraTech® welded?
A. UltraTech® can be Thermally welded or chemically welded to form a homogeneous bond between adjacent sheets of material.
Q. Is is necessary to grind the surface of UltraTech® to weld seams?
A. Unlike polyethylene, which must be abraded on the surface prior to welding. UltraTech® only needs to be wiped clean of any dust or moisture prior to welding. Since grinding is not required, you are assured of having full thickness of the liner in all areas, and need not be concerned about the loss of thickness along each seam.
Q. Is UltraTech® reinforced?
A. UltraTech® is available in 20, 30, and 40 mil thickness as an unsupported membrane. It is also available in a 35 mil thick fabric-reinforced liner.
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Q. Can UltraTech® be used as a methane barrier?
A. Tests in accordance with ASTM D-1434 conclude that the permeability coefficient of UltraTech® is one of the lowest available on the market, making it superior to polyethylene as a methane barrier.
Q. Can reinforced UltraTech® be combined with unsupported UltraTech®?
A. Since the two materials are identical compounds, reinforced and unsupported UltraTech® can be heat or chemically welded together to provide the best combination of materials for your containment application. The unsupported UltraTech® provides high elongation with high tensile strength, while the reinforced UltraTech® provides high dimensional stability. No complicated joining procedures are required.
Q. Where is UltraTech® available?
A. Call us today, toll-free at 800-OK-LINER for the name of the EPI dealer nearest you
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