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Geo FAQ's

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Brownfield / Gas Barriers

Q: What type of barrier materials are typically used for contaminated sites?
A: Until recently, standard 40 and 60 mil HDPE have been used to prevent the migration of contaminates. Raven Industries has developed a material specifically designed for this application. This material, VaporBlock Plus, incorporates a unique barrier layer that is approximately 100 times less permeable to VOC’s and other gases than standard polyethylene.
Q: Are Raven barriers chemically resistant to most all chemicals?
A: Chemical resistance is a relative term in the Geosynthetic Industry. Raven materials are chemically resistant to a wide range of chemicals. For more specifics please contact a Raven representative.
Q: What are the benefits of using geomembrane barriers vs. spray on type barriers?
A: Spray on membranes and geomembrane barriers have some important differences with the main issue being a uniform barrier thickness. Factory produced membrane sheets are manufactured to a uniform thickness across the barrier. Spray on barriers must be applied under specific environmental requirements to be used; such as no moisture in the air or high winds and require a custom applicator for installation. Even with the custom applicator, a uniform thickness across the barrier can still be an issue exposing possible thin spots as containment concerns. Geomembrane barriers may be installed by the existing jobsite crew and can be installed in moist conditions or moderate winds. One other factor is after installation; a geomembrane barrier provides a high puncture strength allowing jobsite traffic during and after installation whereas no traffic, sub grade or concrete are allowed on site when using a spray on barrier until the coating cures to a protective shell.
Q: How will I know if your barrier meets all my specification requirements?
A: Raven will work with you and the Engineer to make sure specifications are met or an equal material is accepted by the Engineer.
Q: Why should I choose Raven materials over other suppliers?
A: As with most products in the marketplace, all geomembranes are not made with the same level of quality in areas of design, raw material, manufacturing, and quality assurance. Raven uses high quality additives and premium barrier resin to enhance material properties and performance of our barriers. Our products are all tested to meet high standard requirements through our ISO9001:2008 certified quality management system and verified by quality control testing in our Geosynthetic Institute certified laboratory.

Floating Covers

Q: What materials are typically used for floating covers?
A: The industry standard for floating covers is generally 30-80 mil geomembranes. Depending on specific site details and requirements, we have several options for this application. Our most common geomembrane for floating covers is our 30 to 45 mil reinforced LLDPE polyethylene called Dura-Skrim® J-Series or K-Series. These membranes make a great choice by exceeding the performance and strengths of much thicker non-reinforced materials and keeping the overall handling weight down.
Q: How long can a typical Raven floating cover last in an exposed application?
A: Many of our liners are appropriately stabilized to survive up to 20 years or more in the Continental U.S. Your project location and details will help to determine the expected longevity for your application.
Q: What size covers can Raven Produce?
A: This depends mainly on the material being used. Maximum panel size is primarily governed by weight. We can produce large custom sized panels up to 6,000 lbs to meet your dimensions. Please contact us to discuss your project details and obtain our recommendations for your cover dimensions.
Q: What color covers are available from Raven?
A: We have white and black materials in our standard product lineup and offer many other custom colors available with minimum order requirements.
Q: What is the difference between HDPE and LLDPE Geomembranes?
A: The primary difference between LLDPE (Resin density between 0.917 and 0.924) and HDPE (Resin density between 0.934 and 0.939) geomembranes is flexibility. The ability to conform to irregular surfaces, ease of welding, and stress crack resistance are additional advantages of LLDPE. Selection of one or the other will depend upon your project detail requirements. For instance, if you are lining a pond or pit, you will need a liner that is flexible and conforming as well as highly tear and puncture resistant. After your liner is installed the importance of stress cracking resistance and UV stabilization will be relevant in helping your liner perform as expected.
Q: Why should I choose Raven materials over other suppliers?
A: As with most products in the marketplace, all geomembranes are not made with the same level of quality in areas of design, raw material, manufacturing, and quality assurance. Raven uses high quality carbon black, stabilizers, and resin to enhance material performance. Our products are all tested to meet high standard requirements through our ISO9001:2008 certified quality management system and verified by quality control testing in our Geosynthetic Institute certified laboratory.

Landfill Covers / Caps

Q: What materials are typically used for landfill covers and caps?
A: There are many different designs for capping and closing a landfill cell. Most permanent caps are 40-60 mil textured materials. Some designs use a temporary cover for leachate control and to allow the waste to decompose to use the additional airspace. The most common material used for temporary covers is 6-20 mil reinforced LLDPE material. Raven Industries has super stabilized Dura-Skrim covers meeting GRI-GM22 standard specifications. These are available for exposed applications requiring a life expectancy of 5 years or more.
Q: How will I know if your cover meets all my specification requirements?
A: Raven will work with you and the Engineer to make sure specifications are met or an equal material is accepted by the Engineer for your project.
Q: What color covers are available from Raven?
A: We have white and black materials in our standard product lineup and offer many other custom colors available with minimum order requirements.
Q: How are Temporary Rain Covers held in place?
A: The most common way to hold a rain cover in place is an anchor trench around the perimeter and the use of sandbags to ballast the material to prevent wind uplift.
Q: How many sandbags are needed for my cover size?
A: The number of sandbags needed to properly ballast a cover will be determined by your individual cover dimensions and specified grid placement. We offer a Sandbag Calculator tool on our website to help you easily estimate the approximate number of bags needed based on your input criteria.
Q: My spec calls for a cover meeting the GRI GM22 Standard. Do your covers qualify?
A: The term “GRI” stands for Geosynthetic Research Institute. This organization sets several standards for the geomembrane industry such as GM22. Materials must meet stringent requirements to qualify for these standards. Raven Industries does provide several materials that meet these standards. Please contact a Raven representative for further details.
Q: What size covers can Raven Produce?
A: This depends mainly on the material being used. Maximum panel size is primarily governed by weight. We can produce large custom sized panels up to 6,000 lbs to meet your dimensions. Please contact us to discuss your project details and obtain our recommendations for your cover dimensions.
Q: Why should I choose Raven materials over other suppliers?
A: As with most products in the marketplace, all geomembranes are not made with the same level of quality in areas of design, raw material, manufacturing, and quality assurance. Raven uses high quality carbon black, stabilizers, and resin to enhance material performance. Our products are all tested to meet high standard requirements through our ISO9001:2008 certified quality management system and verified by quality control testing in our Geosynthetic Institute certified laboratory.

Mining

Q: What type of geomembranes liners are typically used for mining applications?
A: The selection of a geomembranes will vary depending on its mining application. Geomembranes for leach pads are often susceptible to puncture and elongation forces. Dura-Skrim K36B and K45B both offer excellent puncture resistance and excellent elongation characteristics. Geomembranes for processing pads may encounter broad PH ranges; so the selection of proper resins are critical. Please contact a Raven representative to help you select the best material for your application.
Q: What mil thickness will I need for my project?
A: Geomembranes come in many different mil thicknesses. Liner thicknesses are determined by the project engineer and the site specific conditions. Speak with one of our geo team experts to best determine a material for your application.
Q: What is the difference between HDPE and LLDPE Geomembranes?
A: The primary difference between LLDPE (Resin density between 0.917 and 0.924) and HDPE (Resin density between 0.934 and 0.939) geomembranes is flexibility. The ability to conform to irregular surfaces, ease of welding, and stress crack resistance are additional advantages of LLDPE. Selection of one or the other will depend upon your project detail requirements. For instance, if you are lining a pond or pit, you will need a liner that is flexible and conforming as well as highly tear and puncture resistant.
Q: Why should I choose Raven materials over other suppliers?
A: As with most products in the marketplace, all geomembranes are not made with the same level of quality in areas of design, raw material, manufacturing, and quality assurance. Raven uses high quality carbon black, stabilizers, and resin to enhance material performance. Our products are all tested to meet our high standard requirements through our ISO9001:2008 certified quality management system and verified by quality control testing in our Geosynthetic Institute certified laboratory.
Q: What color covers are available from Raven?
A: We have white and black materials in our standard product lineup and offer many other custom colors available with minimum order requirements.
Q: Does my Raven liner need to be covered?
A: Raven geomembranes are U.V. stabilized and can be exposed to direct sunlight. The exposed longevity depends on the material selected and location of the project. Speak with one of our geo team experts to best determine a material for your specific application.

Pond Liners

Q: What materials would you recommend to be used for pond liners?
A: Raven produces a wide range of liner membranes and would generally recommend a linear low-density polyethylene (LLDPE) material or a flexible polypropylene (TPO); which provides high elongation, tremendous tear resistance and bursting strength. These are very flexible materials that will conform to almost any surface and can be made into large panels for ease of installation.
Q: How long can a typical Raven liner last in an exposed application?
A: Many of our liners are appropriately stabilized to survive up to 20 years or more in the Continental U.S. Your project location and details will help to determine the expected longevity for your application.
Q: What size liners can Raven Produce?
A: This depends mainly on the material being used. Maximum panel size is primarily governed by weight. We can produce large custom sized panels up to 6,000 lbs to meet your dimensions. Please refer to our website’s liner calculator feature for an estimated panel size and then call a Raven representative for more details.
Q: Are wrinkles acceptable in Raven liners after installation?
A: Yes, Raven liners are made with polyethylene or flexible polypropylene and they may expand and contract as the sheet temperature changes. This is why it is recommended that a minimum amount of slack be added to the liner during installation of the membrane.
Q: Does my Raven liner need to be covered?
A: Raven geomembranes are U.V. stabilized and can be exposed to direct sunlight. The exposed longevity depends on the material selected and location of the project. Speak with one of our geo team experts to best determine a material for your specific application.
Q: What color liners are available from Raven?
A: We have white and black materials in our standard product lineup and offer many other custom colors available with minimum order requirements.
Q: My spec calls for a liner meeting the GRI GM17 Standard. Do your liners qualify?
A: The term “GRI” stands for Geosynthetic Research Institute. This organization sets several standards for the geomembrane industry such as GM17. Materials must meet stringent requirements to qualify for these standards. Raven Industries does provide several materials that meet these standards. Please contact a Raven representative for further details.
Q: What is the difference between HDPE and LLDPE Geomembranes?
A: The primary difference between LLDPE (Resin density between 0.917 and 0.924) and HDPE (Resin density between 0.934 and 0.939) geomembranes is flexibility. The ability to conform to irregular surfaces, ease of welding, and stress crack resistance are additional advantages of LLDPE. Selection of one or the other will depend upon your project detail requirements. For instance, if you are lining a pond or pit, you will need a liner that is flexible and conforming as well as highly tear and puncture resistant. After your liner is installed the importance of stress cracking resistance and UV stabilization will be relevant in helping your liner perform as expected.
Q: Why should I choose Raven materials over other suppliers?
A: As with most products in the marketplace, all geomembranes are not made with the same level of quality in areas of design, raw material, manufacturing, and quality assurance. Raven uses high quality carbon black, stabilizers, and resin to enhance material performance. Our products are all tested to meet high standard requirements through our ISO9001:2008 certified quality management system and verified by quality control testing in our Geosynthetic Institute certified laboratory.

Waste Lagoon Liners

Q: What materials are typically used for Lagoon Liners?
A: The industry standard for lagoon liners is generally 30-80 mil geomembranes. Depending on specific site details and requirements, we have several options for this application. Our most common geomembrane for lagoon liners is our 36 to 45 mil reinforced polyethylene K-Series or non-reinforced polypropylene geomembranes.
Q: Someone told me they had used an 80 mil HDPE liner. Is this the best way to go?
A: Although this is included in the standard line of materials used in this type of application, it would not be our recommended liner due to the heavy weight and non-flexible characteristics of a high density polyethylene. Raven provides several options for this application and all of them include excellent flexibility characteristics. Our reinforced Dura-Skrim® K-Series far exceeds the strength of a much heavier membrane without the weight and handling issues during installation. Raven produces large factory welded panels up to 6,000 lbs to closely meet your lagoon size limiting or eliminating the need for field seaming.
Q: How long can a typical Raven lagoon liner last in an exposed application?
A: Many of our liners are appropriately stabilized to survive up to 20 years or more in the Continental U.S. Your project location and details will determine the expected longevity for your application.
Q: What size liners can Raven Produce?
A: This depends mainly on the material being used. Maximum panel size is primarily governed by weight. We can produce large custom sized panels up to 6,000 lbs to meet your dimensions. Please refer to our website’s liner calculator feature for an estimated panel size and then call a Raven representative for more details.
Q: What color liners are available from Raven?
A: We have white and black materials in our standard product lineup and offer many other custom colors available with minimum order requirements.
Q: My spec calls for a liner meeting the GRI GM17 Standard. Do your liners qualify?
A: The term “GRI” stands for Geosynthetic Research Institute. This organization sets several standards for the geomembrane industry such as GM17. Materials must meet stringent requirements to qualify for these standards. Raven Industries does provide several materials that meet these standards. Please contact a Raven representative for further details.
Q: What is the difference between HDPE and LLDPE Geomembranes?
A: The primary difference between LLDPE (Resin density between 0.917 and 0.924) and HDPE (Resin density between 0.934 and 0.939) geomembranes is flexibility. The ability to conform to irregular surfaces, ease of welding, and stress crack resistance are additional advantages of LLDPE. Selection of one or the other will depend upon your project detail requirements. For instance, if you are lining a pond or pit, you will need a liner that is flexible and conforming as well as highly tear and puncture resistant. After your liner is installed the importance of stress cracking resistance and UV stabilization will be relevant in helping your liner perform as expected.
Q: Why should I choose Raven materials over other suppliers?
A: As with most products in the marketplace, all geomembranes are not made with the same level of quality in areas of design, raw material, manufacturing, and quality assurance. Raven uses high quality carbon black, stabilizers, and resin to enhance material performance. Our products are all tested to meet high standard requirements through our ISO9001:2008 certified quality management system and verified by quality control testing in our Geosynthetic Institute certified laboratory.