Installation Guidelines


Factory Fabricated Compounded 0.25 to 1.52 mm (10 to 60 mil) Thickness Unsupported Geomembranes

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Part 1 – GENERAL

1.01 Guideline Scope

A. This document is an installation guideline for Factory Fabricated Compounded Unsupported Geomembranes 0.25 to 1.52 mm (10 to 60 mil) in thickness as measured by ASTM D5199, D751 or D1777. The applicable product types are as outlined in Part 2 of this guideline, such as PVC. This guideline is designed to provide a minimum set of standards for site installation. However, depending on the complexity and project specific requirements, a qualified design engineering firm may be required for design and installation of the geomembrane. All work shall be in accordance with the project drawings, specifications and QC requirements.

B. Applications
Typical applications for Factory Fabricated Compounded Unsupported Geomembranes include but are not limited to:

  • Irrigation and canal liners
  • Landfill liners
  • Leach pad liners
  • Moisture barriers and covers for athletic fields
  • Golf course and decorative pond liners
  • Soil remediation pads
  • Interim and final landfill and mine reclamation cover systems
  • Shale oil and gas development, e.g., drill pads and various liquid containments
  • Oil and gas production, e.g., various secondary containment applications
  • Mining leach pads and various liquid containment and transport applications
  • Tailings ponds
  • Water reservoirs and ponds
  • Subgrade protection
  • Barriers, blankets, and curtains
  • Rain sheets for ore in mining applications
  • Underslab vapor retarders
1.02 References

American Society for Testing and Materials (ASTM)
1. ASTM D4437. “Standard Practice for Non-destructive Testing (NDT) for Determining the Integrity of Seams Used in Joining Flexible Polymeric Sheet Geomembranes”. ASTM International, West Conshohocken, PA.
2. ASTM D5199. “Standard Test Method for Measuring the Nominal Thickness of Geosynthetics”. ASTM International, West Conshohocken, PA.
3. ASTM D751. “Standard Test Methods for Coated Fabrics”. ASTM International, West Conshohocken, PA.
4. ASTM D1777. “Standard Test Method for Thickness of Textile Materials”. ASTM International, West Conshohocken, PA.
5. ASTM D5641. “Standard Practice for Geomembrane Seam Evaluation by Vacuum Chamber”. ASTM International, West Conshohocken, PA.
6. ASTM D5820. “Standard Practice for Pressurized Air Channel Evaluation of Dual Seamed Geomembranes”. ASTM International, West Conshohocken, PA.
7. ASTM D7865 “Standard Guide for the Identification, Packaging, Handling, Storage, and Deployment of Fabricated Geomembrane Panels”. ASTM International, West Conshohocken, PA.
8. ASTM D7177. “Standard Specification for Air Channel Evaluation of Polyvinyl
Chloride (PVC) Dual Track Seamed Geomembranes.” ASTM International, West Conshohocken,
PA.
9. ASTM D6392. “Standard Test Method for Determining the Integrity of Nonreinforced Geomembrane Seams Produced Using Thermo-Fusion Methods”. ASTM International, West Conshohocken, PA.
10. ASTM D6214. “Standard Test Method for Determining the Integrity of Field Seams Used in Joining Geomembranes by Chemical Fusion Methods.” ASTM International, West Conshohocken, PA.
11. ASTM D6497. “Standard Guide for Mechanical Attachment of Geomembrane to Penetrations or Structures.” ASTM International, West Conshohocken, PA.
12. ASTM D7176. “Standard Specification for Non-Reinforced Polyvinyl Chlorides Used in Buried Applications.” ASTM International, West Conshohocken, PA.
13. ASTM 7272. “Standard Test Method for Determining the Integrity of Seams used in Joining Geomembranes by Pre-manufactured Tape Methods.” ASTM International, West Conshohocken, PA.
14. ASTM D7077. “Standard Practices for Electrical Methods for Locating Leaks in Geomembranes Covered with Water or Earth Materials. ASTM International, West Conshohocken, PA.
15. ASTM D7465. “Standard Specification for EPDM used in Geomembrane Applications.”
ASTM International, West Conshohocken, PA.
16. ASTM D7408. “Standard Specification for Non Reinforced PVC (Polyvinyl Chloride)
Geomembrane Seams.” ASTM International, West Conshohocken, PA.

Other References
1. USEPA (1991). Inspection Techniques For The Fabrication Of Geomembrane Field Seams. Cincinnati, Ohio 45268: U.S. Environmental Protection Agency.
2. Koerner, R. M. (2005). Designing with Geosynthetics (5 ed.). Upper Saddle River, NJ 07458: Pearson Education, Inc.
3. Geosynthetic Research Institute (2012). “Test Frequencies for Destructive Seam Testing Selecting,
variable intervals for taking geomembrane destructive Sample Using the Method of Attributes” GRI GM 14, Geosynthetic Institute, Folsom, PA.
4. Firestone Specialty Products (2011). Technical Specification Guidelines. Indianapolis, IN 46420.

1.03 Submittals

Documents to be included in a submittal to the owner/engineer for review
or approval:

1. Example material warranty and Geomembrane installation warranty.
2. Sample of Geomembrane(s) to be installed including the technical data on the product.
3. Reports on the results of examinations and testing shall be prepared and submitted to the Owner’s Representative.
4. Shop drawings/panel layout for Geomembranes with panel numbers, field seam locations and details, corresponding to shipping labels.
5. Submit resumes or qualifications of the installation supervisor and certified welding technicians.
6. Documentation of manufacturer’s and installer’s qualifications (see section 2.02 below). It is recommended that the welding technicians hold an International Association of Geosynthetic Installers (IAGI) Certified Welding Technician (CWT) certification in reinforced geomembranes
7. The installer shall submit a list of at least ten completed facilities. For each installation, provide: name and type of facility; its location; the date of installation; name and telephone number of contact at the facility; type and thickness of geomembrane and; surface area of the installed geomembrane.
8. The documentation to be submitted by the Fabricator to the Owner varies depending on the Owner’s requirements. Documentation may include copies of tested seam results, certifications, or any other document related to the quality of the geomembranes and their installation.
9. Fabricator and Installer QC Manuals.

Additional submittals to owner/engineer for review or approval
(at completion):

1. Leave the panels packaged until the day the panels are to be installed. If extremely
hot or cold temperatures are present, keep the panels inside at a moderate
temperature. This reduces the force required to unfold the panels.
2. Geomembrane installation warranty. The installer shall guarantee the geomembrane installation against defects in the installation and workmanship for one (1) year commencing with the date of final acceptance.
3. Compilation of pre-qualification test seam samples reports (see section 3.01.D.1
below).
4. Compilation of destructive and non-destructive field seam tests reports (See section 3.01.D below).

Part 2 – PRODUCTS

2.01 Geomembrane Materials

A. Geomembranes included

  1. 1. This Document is an installation guideline for Factory Fabricated Compounded
    Unsupported Geomembranes of 0.25 to 1.52 mm (10-60 mil) in thickness (as
    measured by ASTM D5199, D751 or D1777). The geomembranes included in this
    guideline may be comprised of the following polymers:
    1. a. Chlorosulfonated Polyethylene (CSPE)
    2. b. Polyvinyl Chloride (PVC) and alloys of PVC with other polymers
      1. 1. Alloys with Ethylene Interpolymer Alloy (EIA)
      2. 2. Alloys with nitrile or other types of rubber
      3. 3. Blends and alloys with other compatible polymers
    3. c. Ethylene Propylene Diene Monomer (EPDM)
2.02 Quality Control

A. Manufacturer’s Qualifications
The fabricator of the geomembrane shall have fabricated a minimum of 500,000 m2/
year (5,381,955 ft2/year) of the specified type or similar geomembranes.

B. Fabricators Qualifications
The manufacturer of the specified geomembrane or similar product shall have at least five years of continuous experience in the manufacture of the geomembrane. Additionally, the Manufacturer shall have produced a minimum of 1,000,000 m2 (10,500,000 square feet) of the specified geomembrane or similar product during the last 5 years.

C. Installer’s Qualifications
The Geomembrane Installer shall be the Fabricator, approved Fabricator’s Installer, or an installer/contractor approved by the Owner’s Representative. The geomembrane installer shall have installed at least 10 projects involving a total of 500,000 m2 (5,381,955 ft2) using the specified geomembrane.

It is the responsibility of any of the aforementioned parties to select a Geomembrane Installer with the appropriate degree of experience, personnel, and equipment to accomplish the required quality standards.

Depending upon the complexity of the project, it might be required to perform the installation of the geomembrane(s) under the direction of a field installation Supervisor who shall be responsible throughout the geomembrane installation, for geomembrane panel layout, field seaming, testing, patching, repairs, and all other activities of the Geomembrane Installer.

Geomembrane Arrival at Project Site

A. Geomembrane Unloading

  1. 1. Follow ASTM D7865 Guideline for the Identification, Packaging, Handling, Storage, and Deployment of Fabricated Geomembrane Panels.
  2. 2. Inspect fabricated geomembrane panels prior to unloading from vehicle at project site (e.g. type of material, conditions, etc.). Make any claims for damage with the carrier prior to unloading or shortly after geomembrane unloading.
  3. 3. Materials delivered to site should be off-loaded (using forklift or similar equipment) in a location where minimum handling steps will be required.
  4. 4. While unloading or transferring the fabricated panels from one location to another, prevent damage to the wrapping and the fabricated panel itself.
  5. 5. Any damage during offloading and transferring should be documented by the
    contractor unloading the material and the installer.

B. Storage

  1. 1. Leave the panels packaged in UV protected wrap until the day that the panels are to be installed. If extremely hot or cold temperatures are present, keep the panels inside at a moderate temperature. This reduces the effort required to unfold the panels.
  2. 2. Fabricated panels, when possible, should be stored on pallets off the ground. The storage area should be dry, level, and with a firm base to facilitate lifting; so the panels are not damaged, do not become dirty, and remain dry externally and internally.

Part 3 – EXECUTION

3.01 Installation

A. Subgrade Preparation

  1. 1. A pre-installation inspection shall be requested by the geomembrane installer and
    ALL interested parties before moving panels from the storage location to the placement area. If the subgrade is deemed to be inappropriate for any reason, e.g., roughness, moisture, rock, etc., it should be remediated prior to geomembrane movement and placement.
  2. 2. The geomembrane installer and owner’s representative shall provide daily written acceptance for the surface to be covered by the geomembrane in that day’s operations.
  3. 3. Subgrade surfaces should be free of loose rock fragments (>10 mm or 0.4 inches), sticks, sharp objects, or debris of any kind. The surface should provide a smooth, flat, firm, unyielding foundation for the geomembrane with no sudden, sharp or abrupt changes or break in grade that can tear or damage the geomembrane.
  4. 4. No standing water, mud, vegetation, snow, frozen subgrade, or excessive moisture
    is allowed before geomembrane placement.
  5. 5. All pipes, drains, fitting, etc., which are to be installed beneath the geomembrane, should be in place, backfilled, and ready to be covered with the geomembrane before panel deployment.
  6. 6. An anchor trench in the shape of a “U” or “V” can be used as a perimeter termination
    point for the geomembrane. Installation of the geomembrane shall be started from the anchor trench.

B. Unfolding and Deploying Prefabricated Panels

  1. 1. The geomembrane shall be supplied as a continuous panel with factory seams in the panel to reduce the amount of field seaming and testing.
  2. 2. The geomembrane shall be installed to the limits shown on the project drawings and essentially as shown on approved panel layout drawings.
  3. 3. Fabricated geomembrane panels are normally placed at a starting point on one corner of the area to be lined. The deployment markings on the packaging or label indicate which direction the panel will unfold. Note accordion-folded and rolled panels will unroll in only one principal direction while double accordion-folded panels may unfold in either principal direction.
  4. 4. While unrolling and/or unfolding the geomembrane, inspect the fabricated panel for proper material type and thickness, damage, and/or defects. Repair any damage found.
  5. 5. Provide suitable wind uplift protection with sandbags, sand tubes or other engineer approved ballast such as geotextile rolls after the geomembrane panel is unfolded and deployed into position.
  6. 6. Only material that is to be immediately welded, i.e., during that work-day, should be deployed.
  7. 7. Once the geomembrane is properly placed, the material should be seamed as soon as practical.
  8. 8. After the panels are initially placed in the proper position, remove as many wrinkles as practical. If possible, allow the panels to “relax” by allowing the panel to warm in the sun and then seaming. The edges to be seamed need to be smooth and free of wrinkles to ensure good field seams and no “fish mouths”.

C. Field Seaming
A large advantage of factory fabricated geomembranes is that manufactured rolls of
material are fabricated into large panels in a factory before shipment to the project
site. This minimizes the amount of the field seaming and maximizes the amount of
factory seaming which results in more high quality seams. In particular, the individual
widths of the manufactured geomembrane rolls shall be assembled into large panels
that are custom-designed for the specific project and correspond to the panel layout
diagram. If factory seaming is maximized, field seaming can be reduced by 80 to 95 percent. In other words, only 5 to 20 percent of all seams need to be made in the
field depending on the unit weight of the geomembrane material. This reduction in
field seaming improves seam quality by seaming in controlled conditions, accelerates
construction, minimizes or eliminates destructive field seam tests, reduces weather
exposure issues, allows modular construction, and reduces project costs.
The seaming operation requires a solid, dry, smooth subsurface (see section 3.01 A
Subgrade Preparation).

  1. 1. Field Cleaning of Seams
    1. a. A minimum overlap of 100 mm to 150 mm (4-6 inches) for all field seams types, e.g., thermal fusion, tape, chemical fusion, etc., must be cleaned of
      all dust, dirt, water, and foreign debris no more than 30 minutes prior to the
      seaming operation. Only clean, soft rags should be used for cleaning the
      areas to be seamed.
    2. b. During the cleaning operation, the Geomembrane sheets will be inspected for
      proper type, thickness, and defective areas which must be removed and/or
      repaired prior to seaming.
  2. 2. Field Seaming
    1. a. Factory Fabricated Compounded Unsupported Geomembrane Panels can be field seamed by either of the following methods:
      1. i. Thermal Fusion Welding
      2. ii. Chemical Fusion Welding
      3. iii. Adhesive Bonding
      4. iv. Pre-manufactured Tape Seaming
  3. 3. Field Thermal Welding
    1. a. A major advantage in specifying Compounded Geomembranes is the fact that
      the roll goods for these polymeric materials can be easily factory seamed together
      using chemical fusion, tape, or thermal fusion methods.
    2. b. Thermal seaming is performed with a hot wedge welding machine, which uses
      a heated element to melt the geomembranes to be welded and then presses
      the two melted sheets together to form a fusion bond. When performed properly, wedge welders produce high quality and consistent seams.
    3. c. All thermal welders employ a set point controller to accurately maintain the
      welding temperature within the most efficient welding temperature for the
      material. The pressure wheels are normally adjustable to allow for good material
      bonding after heating.
    4. d. Two wedge arrangements may be used for thermal seaming of Compounded
      Unsupported Geomembranes. The single (or solid) wedge arrangement produces
      a continuous bonded weld not less than 25 mm (1 inch) in width. A
      double (or split) weldge produces two welds with an un-bonded channel between
      them. This channel is intended for use in non-destructive air pressure
      testing; however, air lance and pick tests may also be used on split wedge
      welded seams as well (see section 3.01.D Field Seaming Test Requirements
      below) The double wedge seaming is only performed on geomembranes made
      of PVC or PVC alloys (see section 2.01 Geomembranes Included above).
    5. e. Seaming with a thermal welder is to be undertaken only by persons that have
      been trained and qualified in the use of the equipment (see section 2.02C
      Installer’s Qualifications above). Repairs, maintenance, adjustments, and
      modifications are to be performed only by trained personnel.
    6. f. Temperature controllers on the thermal welding device should be set according
      to type of geomembrane, thickness, ambient temperature, type of heating
      (air v. wedge), rate of seaming, and location of thermocouple within the
      device.
    7. g. It is necessary for the operator to keep constant visual contact with the temperature
      controls, as well as the completed seam exiting the welder to ensure
      adequate welding is occurring. It is not recommended to adjust welding
      parameters without first constructing and testing a trial seam. If the trail
      seam meets minimum acceptable values, the adjustments can be used on the
      field seam (See section 3.01.D.1 Trial Seaming Test Requirements below).
    8. h. Pre-heating of the geomembrane in the seaming area is optional. The amount
      or type of preheating and its timing preceding the actual seaming is at the
      option of the installer.
    9. i. Properly functioning portable electric generators must be available within close proximity of the seaming region and with adequate extension cords to
      complete the entire seam. These generators should be of sufficient size or
      number to handle all seaming electrical requirements. The generator must
      have rubber tires, or be placed on a smooth plate such that it is completely
      stable and it does not damage the geomembrane. Fuel (gasoline or diesel) for
      the generator must be stored away from the geomembrane, and if accidentally
      spilled on the geomembrane it must be removed immediately. The
      areas should be inspected for damage to the geomembrane and repaired if
      necessary.
  4. 4. Chemical Fusion Welding
    1. a. Chemical fusion welding consists of the application of a chemical substance
      (seam bonding solvents) between the overlap of the geomembrane sheets
      that are going to be seamed. This chemical dissolves the surface of the geomembrane
      creating a bond when the material is pressed together. A permanent
      bond is created when the solvent evaporates.
    2. b. All field seams should overlap a minimum of 100-150 mm (4-6 inches) wide.
      A sufficient amount of chemical fusion agent should be applied that, upon
      compressing the seam surfaces together, a thin excess of chemical fusion
      agent is forced out of the seam. Enough time should be provided to make the
      chemical soften the surfaces of the geomembranes in contact before pressing
      them together.
    3. c. A high durometer rubber, nylon, or hand steel roller can be used to compress
      the seam surfaces together releasing any air bubbles until a bond is formed.
    4. d. Chemical solvents are designed to produce adhesive welds in compatible plastic
      films. Contact the geomembrane manufacturer to determine the optimum
      bonding agent for the geomembrane being installed.
    5. e. Chemical seaming is a time dependent process. Enough time should be allowed
      prior to non-destructive or destructive testing. Often a 24 hour cure
      time is required before testing.
  5. 5. Adhesive Bonding
    1. a. Most unsupported compounded geomembranes can be joined with adhesive
      welding. Contact the material manufacturer for a listing of appropriate adhesives
      for the geomembrane in use.
    2. b. Adhesive seams also consist of the application of a chemical substance. However,
      in adhesive seams, the chemical acts as a cementing material and does
      not soften the geomembrane sheets.
    3. c. A minimum overlap of 152 mm (6 inches) should be provided for adhesive
      seaming.
    4. d. Similar to chemical seaming, adhesive seaming is also a time dependent process
      and requires enough time to set up prior to non-destructive or destructive
      testing.
  6. 6. Pre-manufactured Tape Seaming
    1. a. The seaming of adjacent panels should be performed immediately after the
      relaxation of the geomembrane.
    2. b. All panels must be installed without tension and without overlapping by at
      least 102 mm (4 inches). All seams on side slopes must be parallel with the
      slope.
    3. c. For soft or rough subsoils a board of piece of conveyor belt is used under the
      EPDM geomembrane in the area of the seam. The seaming board is moved by
      means of a rope as the seaming process progresses.
    4. d. Moisture in the seam will cause failure.
    5. e. A ballast is not required in tape seaming operations and sufficient bond is
      created using nylon roller pressure.
    6. f. Different tape seaming procedures are available, the 76 mm (3 inch) “in
      seam” and the 152 mm (6 inch) wide tape placed at the overlap.
    7. g. Contact the EPDM geomembrane manufacturer for specific details and methodology
      in Pre-Manufactured Tape Seaming.

D. Field Seaming Test Requirements

    1. Test Seams (Trial Seams)

    1. a. Test seams shall be prepared and tested by the Geomembrane Installer to
      verify that the seaming parameters meet accepted seam values at the start
      of each welding session or at the beginning of each working day whichever
      comes first.
    2. b. Test seams also may be made whenever personnel or equipment are changed
      and when climatic conditions reflect wide changes in geomembrane temperature
      or other conditions that could affect seam quality.
    3. c. A minimum of one test strip per seaming apparatus shall be conducted at the
      start of each welding session during a day and at least every 4 hours or 915
      lineal meters (3000 lineal feet) of field seam per machine, whichever is more
      frequent.
    4. d. Field test seams shall be made using “scrap” material from the same lot as
      the geomembrane being welded in the field because the geomembrane is pre
      -fabricated into panels in a factory. This requirement is necessary to ensure
      that the installed geomembrane panels are not damaged prior to the onset of
      the field welding process because no destructive seam tests shall be conducted
      on factory fabricated seams to preserve integrity of the fabricated
      panels (See section 3.01.D.2.a Non-Destructive Testing of Seam Testing below).
    5. e. Test seaming shall be conducted under ambient conditions and with the same
      equipment, geomembrane, and operator as field seaming on the fabricated
      panels. The test seams shall be at least 1.8 meter (6 feet) long for all types
      of field seams.
    6. f. Test seams prepared with chemical bonding or adhesives may need to cure
      for a period of time before testing. Follow the manufacturer’s instructions
      for the curing times of seaming chemicals and adhesives.
    7. g. If there is no area or equipment on site to provide for these seam requirements,
      seam strength can be verified for production using trial welds sent to
      an independent testing laboratory to verify quality.
    8. h. If a test seam fails, an additional test seam shall be immediately completed.
      If the additional test seam fails, the seaming apparatus shall be rejected and
      not used until the deficiencies are corrected and a successful full test seam is
      produced.
    9. i. Each test seam shall be labeled with date, geomembrane temperature,
      weather conditions, number of seaming unit, panel identification, seam number
      or test location, technician performing the test seam, and a pass or fail
      description.
    10. j. There is a variance in the ASTM seam testing methods utilized for the geomembranes
      specified in this document. The Design Engineer should include
      the specific ASTM test methods that are relevant to the specified material.
  1. 2. Non-Destructive Testing (NDT) of Seam Testing
    1. a. ALL FIELD SEAMS shall be non-destructively tested by the Geomembrane Installer
      over the full length of the seams before the seam is covered. Each
      seam shall be numbered or otherwise designated. The location, date, test
      unit, name of the technician, name of QC person, and outcome of all NDT
      shall be recorded and submitted to the Owner’s Representative.
    2. b. Testing should be performed as the seaming progresses, not at the completion
      of all field seaming, unless agreed to in advance by the Owner’s Representative.
      All defects found should be repaired, re-tested, and remarked to
      indicate acceptable completion of repair.

    NDT of field seams shall be performed using one or more of the following methods:

  2. 3. Air Channel Test (ASTM D7177)
    1. a. Air channel testing is only applicable to double (split) wedge seams.
    2. b. Equipment for testing dual track thermal seams shall be comprised of but not
      limited to: an air pump equipped with a pressure gauge capable of generating
      and sustaining a pressure of 350 kPa (50 psi), mounted on a cushion to protect
      the geomembrane; and a manometer equipped with an approved pressure
      feed device.
    3. c. The testing activities shall be performed by the geomembrane installer. Both
      ends of the seam to be tested shall be sealed and an approved pressure feed
      device.
    4. d. The testing activities shall be performed by the geomembrane installer. Both
      ends of the seam to be tested shall be sealed and an approved pressure feed
      device inserted into the channel created by the dual track thermal weld. The
      air pump shall be adjusted as per ASTM D7177.
    5. e. Inflated seams shall be inspected by the geomembrane installer during the
      air pressure test to identify any irregular shape of the inflated seam which
      may be an indicator of a lower quality weld.
    6. f. Results of the air pressure testing shall be marked on the seam tested and
      logged on the air pressure testing record.
  3. 4. Air Lance Testing (ASTM D 4437)
    1. a. The Geomembrane Installer shall provide an air compressor, air hose, and
      air lance wand with a pressure gauge capable of measuring air flow to the
      tip. The testing shall be performed by experienced technicians familiar with
      this testing procedure.
    2. b. This non-destructive test involves placing the air lance wand 6 to 12 mm (¼
      to ½ inch), but not more than 50 mm (2 inches), from the edge of a completed
      seam and closely monitoring the backside of the sheet for any air
      penetration through the seam, loose edges, riffles, and/or noise. If air penetrates
      the seam area, the technician will either see this visibly or hear it
      audibly and the area shall be marked for repair.
  4. 5. Vacuum Box Testing (ASTM D5641)
  5. NOTE: Vacuum box testing is not appropriate for all flexible products. Some
    flexible materials will pull up or adhere to the screen of the vacuum box and
    false values can result. Contact the material manufacturer for guidance on
    whether you should vacuum box test the geomembrane being used.

    1. a. Apply soapy solution to seam area to be tested.
    2. b. Place vacuum box with clean viewing glass along seam.
    3. c. Ensure sealing foam around bottom of box is well seated and provides a
      good seal.
    4. d. It may be necessary to “work” the box into place and to use some wet rags
      to get a good seal.
    5. e. Apply a minimum pressure in the box of about 27.6 kPa (4 psi) to test the
      seams.
    6. f. Monitor the seam for soap bubbles for at least 5 seconds.
    7. g. Mark any locations where bubbles indicate leaks for repairs.
    8. h. If no bubbles occur after 5 seconds, relieve vacuum and move to next seam
      section.
    9. i. An overlap of about 75 mm (3 inches) should be tested between two consecutive
      testing sections along the field seam being tested.
    10. j. With thinner products it may be beneficial to install a rigid mesh over the
      bottom of the box to prevent the geomembrane from being sucked or pulled
      into the vacuum box. Avoid rough edges that might damage the geomembrane.
  6. 6. Electric Leak Location (ELL) Survey (ASTM D7002 or ASTM D7007)
    1. a. An ELLS is applicable for geomembranes made of polyethylene, polyvinyl
      chloride, chlorosulfonated polyethylene, bituminous geomembrane, and any
      other electrically-insulating materials.
    2. b. The water puddle detection system usually consists of a horizontal water
      spray manifold with multiple nozzles to spray water on the geomembrane, a
      squeegee to push resultant water puddle, and a hand assembly. A pressurized
      water source is connected to the spray manifold using a hose.
    3. c. Direct current power supplies are used for ELLS; however an alternating current
      (output of 12 to 30 volts AC) could be used.
    4. d. The water puddle created is pushed systematically over the geomembrane to
      locate the points where the electrical current flow increases.
    5. e. The signal of the probe is connected to an electronic detector assembly that
      converts the electrical signal to the detector and an audible signal that increases
      in pitch and amplitude as signal increases.
    6. f. When a leak is detected, the location of the leak is then marketed or measured
      relative to fixed points.
    7. g. The leak detection sensitivity can be very good for this technique. Leaks
      smaller than 1 mm in diameter and leaks through seams in the geomembrane
      are routinely found.
    8. h. The survey rate depends primarily on the manifold and squeegee and presence
      of wrinkles and waves in geomembrane.
  7. 7. Destructive Field Seam Testing
  8. The frequency of destructive field samples to be taken at a specific project depends
    on the type of geomembrane material.

    1. a. The Geosynthetics Research Institute give the following recommendation:
      One destructive test sample per 150 lineal meters (492 linear feet) of field
      seam length or another predetermined length in accordance with GRI GM 14
      shall be obtained by the Geomembrane Installer from a location specified by
      the Owner’s Representative. The Geomembrane Installer shall not be informed
      in advance of the sample location. Testing should be arranged such
      that test results are provided prior to completion of geomembrane installation.
      Samples shall be cut by the Geomembrane Installer as directed by the
      Owner’s Representative as seaming progresses.
    2. b. All field samples shall be marked with their sample number and seam number.
      The sample number, date, time, location, and seam number shall be
      recorded. The Geomembrane Installer shall repair all of the holes in the geomembrane
      created during the seam sampling process. All patches shall be
      vacuum box tested or spark tested to ensure no leakage. If a patch cannot be
      permanently installed over the test location the same day of sample collection,
      a temporary patch shall be tack welded or hot air welded over the
      opening until a permanent patch can be affixed.
    3. c. The destructive sample size shall be 300 mm (12 inches) wide by 1 m (39
      inches) long with the seam centered lengthwise. The sample shall be cut into
      three equal sections and distributed as follows: one section given to the Owner’s
      Representative as an archive sample; one section given to the Owner’s
      Representative for laboratory testing as specified in paragraph (g) below; and
      one section retained by the Geomembrane Installer for field testing as specified in paragraph (d) below.
    4. d. For field testing, the Geomembrane Installer will follow ASTM D6392 for thermally
      welded seams, ASTM D6214 for chemically welded or adhesive seams
      and ASTM D7272 for taped seams.
    5. e. Standard ASTM non-destructive test (NDT) methods shall be used to evaluate
      seams. The Engineer shall designate the appropriate standard NDT method
      dependent on the type of geomembrane to be installed.
    6. f. Reports of the results of examinations and testing shall be prepared and submitted
      to the Owner’s Representative.
    7. g. For field seams, if a laboratory test fails, that shall be considered as an indicator
      of the possible inadequacy of the entire seamed length corresponding
      to the test sample. Additional destructive test portions shall then be taken
      by the Geomembrane Installer at locations indicated by the Engineer; typically
      3 m (10 feet) on either side of the failed sample.
    8. h. On either side of the failed sample and laboratory seam tests shall be performed.
      Passing tests shall be an indicator of adequate seams. Failing tests
      shall be an indicator of non-adequate seams and all seams represented by
      the destructive test location shall be repaired with a cap-strip extrusion weld
      to all sides of the capped area by one of the methods discussed above but most likely chemical or adhesive. All cap-strip seams shall be nondestructively
      vacuum box tested until adequacy of the seams is achieved. Cap
      strip seams exceeding 50 m (164 feet) shall be destructively tested.

    NOTE: Historically, destructive seam testing has been conducted every 150 lineal meters.
    (approximately 500 lineal feet). There is a movement toward doing less destructive testing mid
    field seam. The rationale behind this change is that when a hole is cut from a seam, it is repaired
    with a seam that is not as good as the original. There are several methods used within the industry
    to reduce the amount of destructive seam sampling done. One method involves the use of
    both destructive and non-destructive methods for testing seam integrity. First, the seam must be
    made with split-wedge welder and successfully air channel tested. Also a destructive seam sample
    is taken from the anchor trench and tested. If both tests are successful, then no destructive
    seams are taken from the field seam. If either test fails, then destructive sampling is conducted
    on the field seam. A second method is detailed in GRI’s GM 14 guideline “Selecting Variable Intervals
    for Taking Geomembrane Destructive Seam Samples Using the Method of Attributes.” A simplified
    explanation of this method is that good seaming performance is rewarded by extending the
    destructive sampling interval. Poor seaming performance is penalized.

  9. 8. Identification of Defects
    1. a. Seams shall be inspected by the geomembrane installer and the owner’s representative
      before, during, and after field seaming to identify all dirty and
      wrinkled areas and any defects.
  10. 9. Evaluation of Defects
    1. a. Each suspect location (both in geomembrane seam and non-seam areas) shall
      be non-destructively tested. Each location which fails non-destructive testing
      shall be marked, numbered, measured, and posted on the daily installation
      drawings and subsequently repaired.
    2. b. Defective seams, tears or holes shall be repaired by capping or cutting out the
      defective seam and re-seaming. Single seams in excess of 20% of their length
      requiring repair should be entirely removed and re-welded.
    3. c. Each patch or cap strip shall extend a minimum of 150 mm (6 inches) in all
      directions beyond the defect.
    4. d. All repairs shall be located, measured, non-destructively tested, and recorded.

E. Geomembrane Penetrations
Any structure or containment area built from man-made materials (metal, concrete, etc.)
shall not allow protrusions, pinch points, or movement of the supporting structure that
might damage the geomembrane and adversely affect the ability of the geomembrane to
perform its containment function. Follow ASTM D6497 for guidance for the attachment of
geomembranes to structures. All pipes, drains, fitting, etc., which are to be installed beneath
the geomembrane, should be in place and ready to be covered with the geomembrane
before geomembrane deployment. If possible, avoid cutting the geomembrane at
details by using factory fabricated pipe boots that can be seamed to panels in the field. The following directions provide additional details for handling geomembrane penetrations:

  1. 1. Pipes
    1. a. Whenever possible, avoid slitting geomembrane panels for piping details until
      a prefabricated pipe boot is ready for immediate installation. Cuts made in
      the geomembrane for clearance over penetrations should always be made as
      small as possible to minimize patch work. Generally, it is preferred to let the
      geomembrane straddle a relatively small protrusion (for later detail work) provided
      that a rag or towel is taped over the pipe to avoid damage to the geomembrane.
    2. b. Factory prepared pipe boots should fit snugly but not require excessive force
      to pull over a pipe. If a pipe boot feels overly snug but workable, try applying
      either talc powder or using compressed air with a nozzle to float the boot
      sleeve over and along the pipe.
    3. c. Pipe boots should never be used if the force required to install them stresses
      or weakens the boot. When properly installed, the pipe boot will lay flat
      against grade surrounding pipe without leaving pockets that may become
      stressed during or after placement of backfill.
    4. d. Pipe boot aprons should be seamed to the parent geomembrane using one of
      the repair techniques described in the Seaming Section above (see 3.01C Field
      Seaming).
    5. e. Proper leak-proof sealing of pipe boots should be verified by non-destructive
      methods (see section 3.01 D Field Seaming Test Requirements). The pipe boot
      sleeve should be attached to the pipe using butyl tape between the pipe and
      boot and two stainless steel clamps.
    6. f. When cover materials are not used (see section 3.01.F Cover Materials below),
      splash pads or additional geomembrane layers shall be used for all inflow
      pipes to prevent long term wear and damage to the geomembrane caused by
      the direct impact of the inflow on the geomembrane panels. The pads should
      be welded on top of the geomembrane panels and tested according to sections
      3.01.C and D, respectively. Common splash panel sizes are 1.2 to 1.8 m (4 to 6
      ft.) in all directions. However, larger sizes may be required depending on the
      amount of inflow pipes and the height to the discharge point.
  2. 2. Concrete
    1. a. Where bonding a geomembrane to concrete (or masonry) is required, the concrete
      surface should be smooth, clean, dry, and free of any sharp protrusions
      or rock in the backfill. Geomembrane to concrete seals shall be accomplished
      with mechanical anchors (e.g. fasteners, termination bars). An approved sealant
      and an approved gasket material is placed between the geomembrane and
      the concrete surface to ensure sealing.
    2. b. The geomembrane fixed to a concrete structure must be on firm soil subgrade
      that will not deform and stretch the geomembrane. Compacting of the soil
      subgrade around such structures must be performed with particular care so
      excessive differential movement between the concrete and soil subgrade does
      not occur.
  3. 3. Drains
    1. a. The geomembrane shall be mechanically fastened to the concrete structure at
      the location of water discharge. This detail requires the installation of a concrete
      base or structure at the location of the drain.
    2. b. Where water enters or exits the geomembrane area, e.g., ponds, reservoirs,
      and canals, this point must have proper geomembrane termination so as not
      to damage the geomembrane. The area of inflow must be anchored with a
      trench or attached to a structure as designed by the Project Engineer or Design
      Professional. The geomembrane is installed and then anchored to the
      concrete prior to the covering with soil.
    3. 4. Aerators
      1. a. Geomembrane design in lagoons with aerators should require ballast, e.g. precast
        concrete slab, on the geomembrane to prevent uplift and to provide a
        pad to support the aerator when the water level is lowered. Many examples
        exist of geomembrane damage due to an aerator settling on the geomembrane
        or where the geomembrane was lifted into the aerator. Other aerator damage
        is frequently evidenced as cuts in the geomembrane along a specific elevation
        on the side slope where the aerators have been pulled to shore for maintenance.
        Geomembrane sheets are easily damaged by the sharp edges of a 6
        mm (0.25 inch) thick stainless steel plate of an aerator.

    F. Cover Materials

    1. 1. When placing cover material or initially filling the containment area, it is important
      to ballast the geomembrane into the perimeter anchor trench before covering
      or filling. This can cause undue stress and tension on the geomembrane
      along flat and sloped areas during the covering process. The anchor trench or perimeter
      shelf area should be the last area covered to complete the cover process.
    2. 2. Under all operating conditions, protection of the geomembrane will be required.
      Care should be taken when covering the geomembrane to prevent any damage. At
      no time will construction equipment be allowed to operate or drive directly on
      the geomembranes unless it is under 5 psi ground pressure and approved by the
      engineer.
    3. 3. Any damage to the geomembrane should be repaired prior to proceeding with
      cover material placement. Costs associated with repairs are the general contractor’s
      responsibility.
    4. 4. The cover material shall be placed as soon as practical, in conjunction with or
      upon completion of the geomembrane installation or as the installation progresses
      to minimize traffic on the geomembrane and damage.
    5. 5. Access roads for clean soil cover should be maintained to provide 0.45 m (18 inch)
      minimum and for heavier equipment on haul roads a minimum of 0.90 m (36 inch)
      preferable between the excavation equipment and geomembrane at all times.
      Cover soil requirements should be verified before placement with the Design Professional
      and geomembrane installer. Heavy equipment should operate on a minimum
      1 meter (3 foot) thick roadway where the “haul road” is established in and
      out of the containment area.
    6. 6. Additionally, a protection geotextile layer may be needed in rougher soil conditions
      between the geomembrane and the cover materials. The use of a protection
      layer should be verified with the Design Professional and geomembrane fabricator.
    7. 7. Cover material shall consist of 12 mm (0.5 inch) minus particles, clean rounded
      soils or gravels free of sharp edges, sticks, metal, rubbish, and debris or foreign
      materials. Site specific materials or sizes may be acceptable. It is recommended
      that the contractor receive prior written approval of acceptance of the cover materials from a geomembrane representative and/or Design Professional before
      covering the geomembrane.
    8. 8. Cover soils should be dumped and leveled over the geomembrane and not pushed
      from one end to the other to minimize rolling and wrinkling of the geomembrane
      beneath the soils. Cover soil should always be placed from the bottom to the top
      of slopes to avoid stressing the geomembrane and slope stability problems.
    9. 9. Equipment should be turned in long sweeping turns and not spun quickly to eliminate
      the chance of tires digging down to the geomembrane thru the cover soil and
      wrinkling or stretching the geomembrane.
    10. 10. If geomembrane damage does occur during construction, cover placement, and/or
      filling, DO NOT COVER IT UP. Advise the foreman and CQA personnel so repair can
      be made and documented which will make doing the repair a lot easier than after
      cover soil placement or filling.

    G. Field Acceptance

    1. 1. The Geomembrane will be accepted by the Owner’s Representative when all of
      the following have been completed:
      1. a. The entire installation is finished or on agreed upon subsections of the installation
        are finished (3.01 A through 3.01F).
      2. b. All Installer’s QC documentation is complete and submitted to the Owner.
      3. c. Verification of the adequacy of all field seams and repairs and associated geomembrane
        testing is complete.

    H. Site Clean Up and Demobilization

    1. 1. On completion of installation, the geomembrane installer shall dispose of all
      waste and scrap material in a location provided and approved by the owner. The
      installer should also remove all equipment used in connection with the work
      herein, and shall leave the premises in a neat and acceptable manner. No scrap
      material shall be left on the completed surface of the geomembrane.
    2. 2. Excess material shall be cut from the anchor trench areas and all scrap, sand
      bags, and debris, shall be removed just prior to final backfill of anchor trench
      with select cover soil.

    Part 4 – MEASUREMENT AND PAYMENT

    4.01 Measurement and Payment

    As per project specifications

    Thank you to Mr. Ronald Frobel for reviewing and commenting on this document.

    Acknowledgments:

    This document was prepared by graduate student Rafael Villarreal and Professor
    Timothy D. Stark of the University of Illinois at Urbana-Champaign.


International Association of Geosynthetic Installers

Download PDF

The information herein has been composed by IAGI in accordance with current
quality control and quality assurance standards of the geomembrane industry.
Final determination of the suitability of any information or material for the use
contemplated and its manner of use is the sole responsibility of the user.

Part 1 – GENERAL

1.01 Summary

A. This specification includes furnishing and installing HDPE and LLDPE
geomembranes with a formulated sheet density of 0.940 g/cc or greater associated
with HDPE geomembranes and a formulated sheet density of 0.939 or less for
LLDPE geomembranes. Geomembranes with both smooth and textured surfaces are
included.

1.02 References
  1. A. American Society for Testing and Materials (ASTM):
    1. 1. D 638, Standard Test Method for Tensile Properties of Plastics.
    2. 2. D 751, Standard Test Methods for Coated Fabrics.
    3. 3. D 792, Standard Test Methods for Density and Specific Gravity (Relative
      Density) of Plastics by Displacement.
    4. 4. D 1004, Standard Test Method for Initial Tear Resistance of Plastic Film and
      Sheeting.
    5. 5. D 1204, Standard Test Method for Linear Dimensional Changes of Non Rigid
      Thermoplastic Sheeting or Film at Elevated Temperature.
    6. 6. D 1238, Standard Test Method for Flow Rates of Thermoplastics by Extrusion
      Plastometer.
    7. 7. D 1505, Standard Test Method for Density of Plastics by Density-Gradient
      Technique.
    8. 8. D 1603, Standard Test Method for Carbon Black in Olefin Plastics.
    9. 9. D 3895, Test Method for Oxidative Induction Time of Polyolefins by Thermal
      Analysis.
    10. 10. D 4218, Test Method for Determination of Carbon Black Content in
      Polyethylene Compounds by the Muffle-Furnace Technique.
    11. 11. D 4437, Standard Practice for Determining the Integrity of Field Seams Used
      in Joining Flexible Polymeric Sheet Geomembranes.
    12. 12. D 4833, Test Method for Index Puncture Resistance of Geotextiles,
      Geomembranes and Related Products.
    13. 13. D 5199, Standard Test Method for Measuring Nominal Thickness of Smooth
      Geomembranes.
    14. 14. D 5397, Standard Test Method for Evaluation of Stress Crack Resistance of
      Polyolefins using Notched Constant Tensile Load Test.
    15. 15. D 5596, Standard Practice for Microscopical Examination of Pigment
      Dispersion in Plastic Compounds.
    16. 16. D 5641, Standard Practice for Geomembrane Seam Evaluation by Vacuum
      Chamber.
    17. 17. D 5721, Practice for Air-Oven Aging of Polyolefin Geomembranes.
    18. 18. D 5820, Test Method for Air Testing.
    19. 19. D 5885, Test Method for Oxidative Induction Time of Polyolefin
      Geosynthetics by High Pressure Differential Scanning Calorimetry.
    20. 20. D 5994, Standard Test Method for Measuring Nominal Thickness of
      Textured Geomembranes
    21. 21. D 6365, Standard Practice for the Nondestructive Testing of Geomembrane
      Seams using The Spark Test
    22. 22. D5820-95, Pressurized Air Channel Test for Dual Seamed Geomembranes
  2. B. Geosynthetic Research Institute (GRI):
    1. 1. GRI GM 9, Cold Weather Seaming of Geomembranes
    2. 2. GRI GM 10, The Stress Crack Resistance of HDPE Geomembrane Sheet
    3. 3. GRI GM 13, Test Properties, Testing Frequency for High Density
      Polyethylene (HDPE) Smooth and Textured Geomembranes
    4. 4. GRI GM 14, Test Frequencies for Destructive Seam Testing Selecting,
      variable intervals for taking geomembrane destructive samples using the method
      of attributes.
    5. 5. GRI GM 12, Measurement of the Asperity Height of Textured Geomembranes
      Using a Depth Gage
    6. 6. GRI GM 17, Test Methods, Test Properties and Testing Frequency for Linear
      Low Density Polyethylene (LLDPE) Smooth and Textured Geomembranes
    7. 7. GRI GM 19, Seam Strength and Related Properties of Thermally Bonded
      Polyolefin Geomembranes
1.03 Submittals
  1. A. Submit under provisions of Section 01300, Submittals.
  2. B. Submit the following to the Engineer or Owner, for review and approval, within a
    reasonable time so as to expedite shipment or installation of the Geomembrane:
    1. 1. Documentation of manufacturer’s qualifications as specified in subsection
      1.04A of this Section.
    2. 2. Manufacturer’s Quality Control program manual or descriptive documentation.
    3. 3. A material properties sheet, including at a minimum all properties specified in
      GRI GM 13, including test methods used.
    4. 4. Sample of the material.
    5. 5. Documentation of Installer’s qualifications, as specified below and in
      subsection 1.04B of this Section.
      1. a. Submit a list of at least ten completed facilities. For each installation,
        provide: name and type of facility; its location; the date of installation; name
        and telephone number of contact at the facility; type and thickness of
        geomembrane and; surface area of the installed geomembrane.
      2. b. Submit resumes or qualifications of the Installation Supervisor, Master
        Seamer and Technicians to be assigned to this project.
      3. c. Quality Control Program.
    6. 6. Example Material Warranty and Liner Installation Warranty
  3. C. Shop Drawings
    1. 1. Submit copies of shop drawings for engineer’s approval within a reasonable
      time so as not to delay the start of geomembrane installation. Shop drawings shall
      show the proposed panel layout identifying seams and details. Seams should
      generally follow the direction of the slope. Butt seams or roll-end seams should
      not occur on a slope unless approved by the Owner’s Representative. Butt seams
      on a slope, if allowed, should be staggered.
    2. 2. Placement of geomembrane should not be allowed to proceed until Owner’s
      Representative has received and approved the shop drawings.
  4. D. Additional Submittals (In-Progress and at Completion)
    1. 1. Manufacturer’s warranty (refer to subsection 1.07).
    2. 2. Geomembrane installation warranty (refer to subsection 1.08).
    3. 3. Daily written acceptance of subgrade surface (refer to subsection 3.01.C).
    4. 4. Low-temperature seaming procedures if applicable (refer to subsection
      3.03.A).
    5. 5. Prequalification test seam samples (refer to subsection 3.05.A.6).
    6. 6. Field seam non-destructive test results (refer to subsection 3.05.B.1).
    7. 7. Field seam destructive test results (refer to subsection 3.05.C.6).
    8. 8. Daily field installation reports (refer to subsection 3.05.G).
    9. 9. Installation record drawing, as discussed in subsection 3.05.
1.04 Quality Control
  1. A. Manufacturer’s Qualifications: The manufacturer of geomembrane of the type
    specified or similar product shall have at least five years experience in the
    manufacture of such geomembrane. In addition, the geomembrane manufacturer
    shall have manufactured at least 1,000,000 M2 (10,000,000 FT2) of the specified type
    of geomembrane or similar product during the last five years.
  2. B. Installer’s Qualifications
    1. 1. The Geomembrane Installer shall be the Manufacturer, approved
      Manufacturer’s Installer or a contractor approved by the Owner’s Representative
      to install the geomembrane.
    2. 2. The Geomembrane Installer shall have at least three years experience in the
      installation of the specified geomembrane or similar. The Geomembrane Installer
      shall have installed at least 10 projects involving a total of 500,000 M2
      (5,000,000FT2) of the specified type of geomembrane or similar during the last
      three years.
    3. 3. Installation shall be performed under the direction of a field Installation
      Supervisor who shall be responsible throughout the geomembrane installation, for
      geomembrane panel layout, seaming, patching, testing, repairs, and all other
      activities of the Geomembrane Installer. The Field Installation Supervisor shall
      have installed or supervised the installation and seaming of a minimum of 10
      projects involving a total of 500,000 M2 (5,000,000 FT2) of geomembrane of the
      type specified or similar product.
    4. 4. Seaming shall be performed under the direction of a Master Seamer (who may
      also be the Field Installation Supervisor or Crew Foreman) who has seamed a
      minimum of 300,000M2 (3,000,000FT2) of geomembrane of the type specified or
      similar product, using the same type of seaming apparatus to be used in the
      current project. The Field Installation Supervisor and/or Master Seamer shall be
      present whenever seaming is performed.
    5. 5. All seaming, patching, other welding operations, and testing shall be
      performed by qualified technicians employed by the Geomembrane Installer.
1.05 Delivery, Storage and Handling
  1. A. Each roll of geomembrane delivered to the site shall be labeled by the
    manufacturer. The label shall be firmly affixed and shall clearly state the
    manufacturer’s name, product identification, material thickness, roll number, roll
    dimensions and roll weight.
  2. B. Geomembrane shall be protected from mud, dirt, dust, puncture, cutting or any
    other damaging or deleterious conditions.
  3. C. Rolls shall be stored away from high traffic areas. Continuously and uniformly
    support rolls on a smooth, level prepared surface.
1.06 Project Conditions
  1. A. Geomembrane should not be installed in the presence of standing water, while
    precipitation is occurring, during excessive winds, or when material temperatures are
    outside the limits specified in Section 3.03.
1.07 Material Warranty

As agreed by project participants.

1.08 Geomembrane Installation Warranty
  1. A. The Geomembrane Installer shall guarantee the geomembrane installation against
    defects in the installation and workmanship for 1 year commencing with the date of
    final acceptance.
1.09 Geomembrane Pre-Construction Meeting
  1. A. A Geomembrane Pre-Construction Meeting shall be held at the site prior to
    installation of the geomembrane. At a minimum, the meeting shall be attended by the
    Geomembrane Installer, Owner, Owner’s representative (Engineer and/or CQA
    Firm), and the Earthwork Contractor.
  2. B. Topics for this meeting shall include:
    1. 1. Health and Safety
    2. 2. Lines of authority and communication. Resolution of any project document
      ambiguity.
    3. 3. Methods for documenting, reporting and distributing documents and reports.
    4. 4. Procedures for packaging and storing archive samples.
    5. 5. Review of time schedule for all installation and testing.
    6. 6. Review of panel layout and numbering systems for panels and seams including
      details for marking on geomembrane.
    7. 7. Procedures and responsibilities for preparation and submission of as-built
      panel and seam drawings.
    8. 8. Temperature and weather limitations. Installation procedures for adverse
      weather conditions. Defining acceptable subgrade, geomembrane, or ambient
      moisture and temperature conditions for working during liner installation.
    9. 9. Subgrade conditions, dewatering responsibilities and subgrade maintenance
      plan.
    10. 10. Deployment techniques including allowable subgrade for the geomembrane.
    11. 11. Plan for controlling expansion/contraction and wrinkling of the
      geomembrane.
    12. 12. Covering of the geomembrane and cover soil placement.
    13. 13. Measurement and payment schedules.
    14. 14. Responsibilities of each party.
  3. C. The meeting shall be documented by a person designated at the beginning of
    the meeting and minutes shall be transmitted to all parties.

Part 2 – Products

2.01 Source Quality Control
  1. A. Manufacturing Quality Control
    1. 1. The test methods and frequencies used by the manufacturer for quality
      control/quality assurance of the above geomembrane prior to delivery, shall be in
      accordance with GRI GM 13 for HDPE geomembrane or GRI GM 17 for LLDPE
      geomembrane, or modified as required for project specific conditions.
    2. 2. The manufacturer’s geomembrane quality control certifications, including
      results of quality control testing of the products, as specified in subsection
      2.01.A.3 of this Section, must be supplied to the Owner’s Representative to verify
      that the materials supplied for the project are in compliance with all product and
      or project specifications in this Section. The certification shall be signed by a
      responsible party employed by the manufacturer, such as the QA/QC Manager,
      Production Manager, or Technical Services Manager. Certifications shall include
      lot and roll numbers and corresponding shipping information.
    3. 3. The Manufacturer will provide Certification that the geomembrane and
      welding rod supplied for the project are made from the same material type and are
      compatible.
2.02 Geomembrane
  1. A. The geomembrane shall consist of new, first quality products designed and
    manufactured specifically for the purpose of this work which shall have been
    satisfactorily demonstrated by prior testing to be suitable and durable for such purposes.
    The geomembrane rolls shall be seamless, high density polyethylene (HDPE –
    Formulated Sheet Density ≥ 0.94g/cc) or linear low density polyethylene (LLDPE –
    Formulated Sheet Density ≤ 0.939 g/cc) containing no plasticizers, fillers or extenders
    and shall be free of holes, blisters or contaminants, and leak free verified by 100% in line
    spark or equivalent testing. The geomembrane shall be supplied as a continuous sheet
    with no factory seams in rolls. The geomembrane will meet the property requirements as
    shown in Table A (GRI GM 13) or Table B (GRI GM 17)
  2. B. Material conformance testing by the Owner’s Representative, if required, will be
    conducted using in-plant sampling or as specified for the project.
  3. C. The geomembrane seams shall meet the property requirements as shown in Table
    2, (Attachment B) or as required by project specifications

Part 3 – Execution

3.01 Subgrade Preparation
  1. A. The subgrade shall be prepared in accordance with the project specifications. The
    geomembrane subgrade shall be uniform and free of sharp or angular objects that may
    damage the geomembrane prior to installation of the geomembrane.
  2. B. The Geomembrane Installer and Owner’s Representative shall inspect the surface
    to be covered with the geomembrane on each day’s operations prior to placement of
    geomembrane to verify suitability.
  3. C. The Geomembrane Installer and Owner’s Representative shall provide daily
    written acceptance for the surface to be covered by the geomembrane in that day’s
    operations. The surface shall be maintained in a manner, during geomembrane
    installation, to ensure subgrade suitability.
  4. D. All subgrade damaged by construction equipment and deemed unsuitable for
    geomembrane deployment shall be repaired prior to placement of the geomembrane.
    All repairs shall be approved by the Owner’s Representative and the Geomembrane
    Installer. This damage, repair, and the responsibilities of the contractor and
    Geomembrane Installer shall be defined in the preconstruction meeting.
    1. 3.02 Geomembrane Placement
      1. A. No geomembrane shall be deployed until the applicable certifications and quality
        control certificates listed in subsection 1.03 of this Section are submitted to and
        approved by the Owner’s Representative within the timeframe specified in the
        Contract Documents. If the material does not meet project specifications it shall be
        removed from the work area.
      2. B. The geomembrane shall be installed to the limits shown on the project drawings
        and essentially as shown on approved panel layout drawings.
      3. C. No geomembrane material shall be unrolled and deployed if the material
        temperatures are lower than 0 degrees C (32 degrees F) unless otherwise approved by
        the Owner’s Representative. The specified minimum temperature for material
        deployment may be adjusted by the Owner’s Representative. Temperature limitations
        should be defined in the preconstruction meeting. Typically, only the quantity of
        geomembrane that will be anchored and seamed together in one day should be
        deployed.
      4. D. No vehicular traffic shall travel on the geomembrane other than an approved low
        ground pressure Vehicle or equivalent.
      5. E. Sand bags or equivalent ballast shall be used as necessary to temporarily hold the
        geomembrane material in position under the foreseeable and reasonably – expected
        wind conditions. Sand bag material shall be sufficiently close- knit to prevent soil
        fines from working through the bags and discharging on the geomembrane.
      6. F. Geomembrane placement shall not be done if moisture prevents proper subgrade
        preparation, panel placement, or panel seaming. Moisture limitations should be
        defined in the preconstruction meeting.
      7. G. Damaged panels or portions of the damaged panels which have been rejected shall
        be marked and their removal from the work area recorded.
      8. H. The geomembrane shall not be allowed to “bridge over” voids or low areas in the
        subgrade. The geomembrane shall rest in intimate contact with the subgrade.
      9. I. Wrinkles caused by panel placement or thermal expansion should be minimized in
        accordance with section 1.09 B11.
      10. J. Considerations on Site Geometry: In general, seams shall be oriented parallel to
        the line of the maximum slope. In corners and odd shaped geometric locations, the
        total length of field seams shall be minimized. Seams shall not be located at low
        points in the subgrade unless geometry requires seaming at such locations and if
        approved by the Owner’s Representative.
      11. K. Overlapping: The panels shall be overlapped prior to seaming to whatever extent
        is necessary to affect a good weld and allow for proper testing. In no case shall this
        overlap be less than 75mm (3 in.).
      3.03 Seaming Procedures
      1. A. Cold weather installations should follow guidelines as outlined in GRI GM9.
      2. B. No geomembrane material shall be seamed when liner temperatures are less than
        0 degrees C (32 degrees F) unless the following conditions are complied with:
        1. 1. Seaming of the geomembrane at material temperatures below 0 degrees C (32
          degrees F) is allowed if the Geomembrane Installer can demonstrate to the
          Owner’s Representative, using pre-qualification test seams, that field seams
          comply with the project specifications, the safety of the crew is ensured, and
          geomembrane material can be fabricated (i.e. pipeboots, penetrations, repairs.
          etc.) at sub-freezing temperatures.
        2. 2. The Geomembrane Installer shall submit to the Owner’s Representative for
          approval, detailed procedures for seaming at low temperatures, possibly including
          the following:
          1. 1. Preheating of the geomembrane
          2. 2. The provision of a tent or other device if necessary to prevent heat losses
            during seaming and rapid heat losses subsequent to seaming.
          3. 3. Number of test welds to determine appropriate seaming parameters
      3. C. No geomembrane material shall be seamed when the sheet temperature is above
        75 degrees C (170 degrees F) as measured by an infrared thermometer or surface
        thermocouple unless otherwise approved by the Owner’s Representative. This
        approval will be based on recommendations by the manufacturer and on a field
        demonstration by the Geomembrane Installer using prequalification test seams to
        demonstrate that seams comply with the specification.
      4. D. Seaming shall primarily be performed using automatic fusion welding equipment
        and techniques. Extrusion welding shall be used where fusion welding is not possible
        such as at pipe penetrations, patches, repairs and short (less than a roll width) runs of
        seams.
      5. E. Fishmouths or excessive wrinkles at the seam overlaps shall be minimized and
        when necessary cut along the ridge of the wrinkles back into the panel so as to effect
        a flat overlap. The cut shall be terminated with a keyhole cut (nominal 10 mm (1/2
        in) diameter hole) so as to minimize crack/tear propagation. The overlay shall
        subsequently be seamed. The key hole cut shall be patched with an oval or round
        patch of the same base geomembrane material extending a minimum of 150 mm (6
        in.) beyond the cut in all directions.
      3.04 Pipe and Structure Penetration Sealing System
      1. A. Provide penetration sealing system as shown in the Project Drawings.
      2. B. Penetrations shall be constructed from the base geomembrane material, flat stock,
        prefabricated boots and accessories as shown on the Project Drawings. The prefabricated
        or field fabricated assembly shall be field welded to the geomembrane as
        shown on the Project Drawings so as to prevent leakage. This assembly shall be
        tested as outlined in section 3.05.B. Alternatively, where field non destructive testing
        can not be performed, attachments will be field spark tested by standard holiday leak
        detectors in accordance with ASTM 6365
        Spark testing should be done in areas where both air pressure testing and vacuum
        testing are not possible.
        1. a. Equipment for Spark testing shall be comprised of but not limited to: A hand
          held holiday spark tester and conductive wand that generates a high voltage.
        2. b. The testing activities shall be performed by the Geomembrane Installer by
          placing an electrically conductive tape or wire beneath the seam prior to welding.
          A trial seam containing a non welded segment shall be subject to a calibration test
          to ensure that such a defect (non welded segment) will be identified under the
          planned machine settings and procedures. Upon completion of the weld, enable
          the spark tester and hold approximately 25mm (1 in) above the weld moving
          slowly over the entire length of the weld in accordance with ASTM 6365. If there
          is no spark the weld is considered to be leak free.
        3. c. A spark indicates a hole in the seam. The faulty area shall be located, repaired
          and retested by the Geomembrane Installer.
        4. d. Care should be taken if flammable gases are present in the area to be tested.
      3.05 Field Quality Control

      The Owner’s Representative shall be notified prior to all pre qualification and
      production welding and testing, or as agreed upon in the pre construction meeting.

      1. A. Prequalification Test Seams
        1. 1. Test seams shall prepare and tested by the Geomembrane Installer to verify
          that seaming parameters (speed, temperature and pressure of welding equipment)
          are adequate.
        2. 2. Test seams shall be made by each welding technician and tested in accordance
          with ASTM D 4437 at the beginning of each seaming period. Test seaming shall
          be performed under the same conditions and with the same equipment and
          operator combination as production seaming. The test seam shall be
          approximately 3.3 meters (10 feet) long for fusion welding and 1 meter (3 feet)
          long for extrusion welding with the seam centered lengthwise. At a minimum,
          tests seams should be made by each technician 1 time every 4-6 hours; additional
          tests may be required with changes in environmental conditions.
        3. 3. Two 25 mm (1 in) wide specimens shall be die-cut by the Geomembrane
          Installer from each end of the test seam. These specimens shall be tested by the
          Geomembrane Installer using a field tensiometer testing both tracks for peel
          strength and also for shear strength. Each specimen should fail in the parent
          material and not in the weld, “Film Tear Bond”(F.T.D. failure). Seam separation
          equal to or greater than 25% of the track width shall be considered a failing test.
        4. 4. The minimum acceptable seam strength values to be obtained for all specimens
          tested are listed in Subsection 3.05.C.4 of this Section. Four specimens shall pass
          for the test seam to be a passing seam.
        5. 5. If a test seam fails, an additional test seam shall be immediately conducted. If
          the additional test seam fails, the seaming apparatus shall be rejected and not used
          for production seaming until the deficiencies are corrected and a successful test
          seam can be produced.
        6. 6. A sample from each test seam shall be labeled. The label shall indicate the
          date, geomembrane temperature, number of the seaming unit, technician
          performing the test seam and pass or fail description. The sample shall then be
          given to the Owner’s Representative for archiving.
      2. B. Field Seam Non-destructive Testing
        1. 1. All field seams shall be non-destructively tested by the Geomembrane Installer
          over the full seam length before the seams are covered. Each seam shall be
          numbered or otherwise designated. The location, date, test unit, name of tester
          and outcome of all non-destructive testing shall be recorded and submitted to the
          Owner’s Representative.
        2. 2. Testing should be done as the seaming work progresses, not at the completion
          of all field seaming, unless agreed to in advance by the Owner’s Representative.
          All defects found during testing shall be numbered and marked immediately after
          detection. All defects found should be repaired, retested and remarked to indicate
          acceptable completion of the repair.
        3. 3. Non-destructive testing shall be performed using vacuum box, air pressure or
          spark testing equipment.
        4. 4. Non-destructive tests shall be performed by experienced technicians familiar
          with the specified test methods. The Geomembrane Installer shall demonstrate to
          the Owner’s Representative all test methods to verify the test procedures are valid.
        5. 5. Extrusion seams shall be vacuum box tested by the Geomembrane Installer in
          accordance with ASTM D 4437 and ASTM D 5641 with the following equipment
          and procedures:
          1. a. Equipment for testing extrusion seams shall be comprised of but not limited
            to: a vacuum box assembly consisting of a rigid housing, a transparent
            viewing window, a soft rubber gasket attached to the base, port hole or valve
            assembly and a vacuum gauge; a vacuum pump assembly equipped with a
            pressure controller and pipe connections; a rubber pressure/vacuum hose with
            fittings and connections; a plastic bucket; wide paint brush or mop; and a
            soapy solution.
          2. b. The vacuum pump shall be charged and the tank pressure adjusted to
            approximately 35 kPa (5 psig).
          3. c. The Geomembrane Installer shall create a leak tight seal between the
            gasket and geomembrane interface by wetting a strip of geomembrane
            approximately 0.3m (12 in) by 1.2m (48 in) (length and width of box) with a
            soapy solution, placing the box over the wetted area, and then compressing the
            box against the geomembrane. The Geomembrane Installer shall then close
            the bleed valve, open the vacuum valve, maintain initial pressure of
            approximately 35 kPa (5 psig) for approximately 5 seconds. The
            geomembrane should be continuously examined through the viewing window
            for the presence of soap bubbles, indicating a leak. If no bubbles appear after
            5 seconds, the area shall be considered leak free. The box shall be
            depressurized and moved over the next adjoining area with an appropriate
            overlap and the process repeated.
          4. d. All areas where soap bubbles appear shall be marked, repaired and then
            retested.
          5. e. At locations where seams cannot be non destructively tested, such as pipe
            penetrations, alternate nondestructive spark testing (as outlined in section
            3.04.B) or equivalent should be substituted.
          6. f. All seams that are vacuum tested shall be marked with the date tested, the
            name of the technician performing the test and the results of the test.
        6. 6. Double Fusion seams with an enclosed channel shall be air pressure tested by
          the Geomembrane Installer in accordance with ASTM D 5820 and ASTM D 4437
          and the following equipment and procedures:
          1. a. Equipment for testing double fusion seams shall be comprised of but not
            limited to: an air pump equipped with a pressure gauge capable of generating
            and sustaining a pressure of 210 kPa (30 psig), mounted on a cushion to
            protect the geomembrane; and a manometer equipped with a sharp hollow
            needle or other approved pressure feed device.
          2. b. The Testing activities shall be performed by the Geomembrane Installer.
            Both ends of the seam to be tested shall be sealed and a needle or other
            approved pressure feed device inserted into the tunnel created by the double
            wedge fusion weld. The air pump shall be adjusted to a pressure of 210 kPa
            (30 psig), and the valve closed,. Allow 2 minutes for the injected air to come
            to equilibrium in the channel, and sustain pressure for 5 minutes. If pressure
            loss does not exceed 28 kPa (4 psig) after this five minute period the seam
            shall be considered leak tight. Release pressure from the opposite end
            verifying pressure drop on needle to ensure testing of the entire seam. The
            needle or other approved pressure feed device shall be removed and the feed
            hole sealed.
          3. c. If loss of pressure exceeds 28 kPa (4 psig) during the testing period or
            pressure does not stabilize, the faulty area shall be located, repaired and
            retested by the Geomembrane Installer.
          4. d. Results of the pressure testing shall be recorded on the liner at the seam
            tested and on a pressure testing record.
      3. C. Destructive Field Seam Testing
        1. 1. One destructive test sample per 150 linear m (500 linear ft) seam length or
          another predetermined length in accordance with GRI GM 14 shall be taken by
          the Geomembrane Installer from a location specified by the Owner’s
          Representative. The Geomembrane Installer shall not be informed in advance of
          the sample location. In order to obtain test results prior to completion of
          geomembrane installation, samples shall be cut by the Geomembrane Installer as
          directed by the Owner’s Representative as seaming progresses.
        2. 2. All field samples shall be marked with their sample number and seam number.
          The sample number, date, time, location, and seam number shall be recorded.
          The Geomembrane Installer shall repair all holes in the geomembrane resulting
          from obtaining the seam samples. All patches shall be vacuum box tested or
          spark tested. If a patch cannot be permanently installed over the test location the
          same day of sample collection, a temporary patch shall be tack welded or hot air
          welded over the opening until a permanent patch can be affixed.
        3. 3. The destructive sample size shall be 300 mm (12 in) wide by 1 m (36 in) long
          with the seam centered lengthwise. The sample shall be cut into three equal
          sections and distributed as follows: one section given to the Owner’s
          Representative as an archive sample; one section given to the Owner’s
          Representative for laboratory testing as specified in paragraph 5 below; and one
          section retained by the Geomembrane Installer for field testing as specified in
          paragraph 4 below.
        4. 4. For field testing, the Geomembrane Installer shall cut 10 identical 25 mm (1
          in) wide replicate specimens from his sample. The Geomembrane Installer shall
          test five specimens for seam shear strength and five for peel strength. Peel tests
          will be performed on both inside and outside weld tracks. To be acceptable, 4 of 5
          test specimens must pass the stated criteria in section 2.02 with less than 25%
          separation. If 4 of 5 specimens pass, the sample qualifies for testing by the testing
          laboratory if required.
        5. 5. If independent seam testing is required by the specifications it shall be
          conducted in accordance with ASTM 5820 or ASTM D4437.
        6. 6. Reports of the results of examinations and testing shall be prepared and
          submitted to the Owner’s Representative.
        7. 7. For field seams, if a laboratory test fails, that shall be considered as an
          indicator of the possible inadequacy of the entire seamed length corresponding to
          the test sample. Additional destructive test portions shall then be taken by the
          Geomembrane Installer at locations indicated by the Engineer; typically 3 m (10
          ft) on either side of the failed sample and laboratory seem tests shall be
          performed. Passing tests shall be an indicator of adequate seams. Failing tests
          shall be an indicator of non-adequate seams and all seams represented by the
          destructive test location shall be repaired with a cap-strip extrusion welded to all
          sides of the capped area. All cap-strip seams shall be non-destructively vacuum
          box tested until adequacy of the seams is achieved. Cap strip seams exceeding 50
          M in length (150 FT) shall be destructively tested.
      4. D. Identification of Defects
        1. 1. Panels and seams shall be inspected by the Installer and Owner’s
          Representative during and after panel deployment to identify all defects, including
          holes, blisters, undispersed raw materials and signs of contamination by foreign
          matter.
      5. E. Evaluation of Defects: Each suspect location on the liner (both in geomembrane
        seam and non-seam areas) shall be non-destructively tested using one of the methods
        described in Section 3.05.B. Each location which fails non-destructive testing shall
        be marked, numbered, measured and posted on the daily “installation” drawings and
        subsequently repaired.
        1. 1. If a destructive sample fails the field or laboratory test, the Geomembrane
          Installer shall repair the seam between the two nearest passed locations on both
          sides of the failed destructive sample location.
        2. 2. Defective seams, tears or holes shall be repaired by reseaming or applying a
          extrusion welded cap strip.
        3. 3. Reseaming may consist of either:
          1. a. Removing the defective weld area and rewelding the parent material using
            the original welding equipment; or
          2. b. Reseaming by extrusion welding along the overlap at the outside seam edge
            left by the fusion welding process.
        4. 4. Blisters, larger holes, and contamination by foreign matter shall be repaired by
          patches and/or extrusion weld beads as required. Each patch shall extend a
          minimum of 150 mm (6 in) beyond all edges of the defects.
        5. 5. All repairs shall be measured, located and recorded.
      6. F. Verification of Repairs on Seams: Each repair shall be non-destructively tested
        using either vacuum box or spark testing methods. Tests which pass the nondestructive
        test shall be taken as an indication of a successful repair. Failed tests shall
        be reseamed and retested until a passing test results. The number, date, location,
        technician and test outcome of each patch shall be recorded.
      7. G. Daily Field Installation Reports: At the beginning of each day’s work, the Installer
        shall provide the Engineer with daily reports for all work accomplished on the
        previous work day. Reports shall include the following:
        1. 1. Total amount and location of geomembrane placed;
        2. 2. Total length and location of seams completed, name of technicians doing
          seaming and welding unit numbers;
        3. 3. Drawings of the previous day’s installed geomembrane showing panel
          numbers, seam numbers and locations of non-destructive and destructive testing;
        4. 4. Results of pre-qualification test seams;
        5. 5. Results of non-destructive testing; and
        6. 6. Results of vacuum testing of repairs.
      8. H. Destructive test results shall be reported prior to covering of liner or within 48
        hours.
      3.06 Liner Acceptance
      1. A. Geomembrane liner will be accepted by the Owner’s Representative when:
        1. 1. The entire installation is finished or an agreed upon subsection of the
          installation is finished;
        2. 2. All Installer’s QC documentation is completed and submitted to the owner
        3. 3. Verification of the adequacy of all field seams and repairs and associated
          geomembrane testing is complete.
      3.07 Anchor Trench
      1. A. Construct as specified on the project drawings.
      3.08 Disposal of Scrap Materials
      1. A. On completion of installation, the Geomembrane Installer shall dispose of all
        trash and scrap material in a location approved by the Owner, remove equipment used
        in connection with the work herein, and shall leave the premises in a neat acceptable
        manner. No scrap material shall be allowed to remain on the geomembrane surface.

      Part 4 – Measurement and Payment

      As per project specifications

      Part 5 – GRI GM13 Specifications

      “This section shall include the current GRI GM13 manufacturer’s specification or a
      revision of GRI GM13 specific to the unique project requirements and/or standards, as
      determined by the owner or owners’ agent.”


Factory Fabricated Lightweight ≤ 0.64 mm (25 mil) Thickness Fabric-Supported Geomembranes

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Part 1 – General

1.01 Guideline Scope

This document is an installation guideline for Factory Fabricated Fabric-Supported Lightweight
Geomembranes (0.64 mm or <25 mil in thickness as measured by ASTM D5199, D751 or D1777). The product types are as outlined in Part 2 of this guideline. This guideline is designed to provide a minimum set of standards for site installation. However, depending on the complexity and project specific requirements, a qualified design engineering firm may be required for design and installation specifications of the geomembrane. All work shall be in accordance with the project drawings, specifications and QC requirements.

Applications
Typical applications for factory fabricated Fabric-Supported Lightweight Geomembranes that
are less than 25 mil (0.64 mm) in thickness include but are not limited to:

  • Irrigation and canal liners
  • Moisture barriers and covers for athletic fields
  • Golf course and decorative pond liners
  • Soil remediation pads
  • Interim and final landfill and Mine Reclamation cover systems
  • Shale oil and gas development, e.g., drill pads and various liquid containment
  • Oil and gas production, e.g., various secondary containment applications
  • Mining leach pads and various liquid containment and transport applications
  • Tailings ponds
  • Water reservoirs and ponds
  • Paved and unpaved roadways
  • Subgrade protection
  • Temporary erosion control
  • Barriers, blankets, and curtains
  • Rain sheets for Ore in Mining Applications
  • Underslab vapor retarders
1.02 References

American Society For Testing and Materials (ASTM)

  1. 1. ASTM Standards D4437. “Standard Practice for Non-destructive Testing (NDT) for Determining
    the Integrity of Seams Used in Joining Flexible Polymeric Sheet Geomembranes”.
    ASTM International, West Conshohocken, PA.
  2. 2. ASTM Standards D5199. “Standard Test Method for Measuring the Nominal Thickness of
    Geosynthetics”. ASTM International, West Conshohocken, PA.
  3. 3. ASTM Standards D751. “Standard Test Methods for Coated Fabrics”. ASTM International,
    West Conshohocken, PA.
  4. 4. ASTM Standards D1777. “Standard Test Method for Thickness of Textile Materials”.
    ASTM International, West Conshohocken, PA.
  5. 5. ASTM Standards D5641. “Standard Practice for Geomembrane Seam Evaluation by Vacuum
    Chamber”. ASTM International, West Conshohocken, PA.

Other References

  1. 1. USEPA. (1991). Inspection Techniques For The Fabrication Of Geomembrane Field
    Seams. Cincinnati, Ohio 45268: U.S. Environmental Protection Agency.
  2. 2. Koerner, R. M. (2005). Designing with Geosynthetics (5 ed.). Upper Saddle River, NJ
    07458: Pearson Education, Inc.
  3. 3. Geosynthetic Research Institute (2012). “Standard Specification for Test Methods, Required
    Properties and Testing Frequencies for Scrim Reinforced Polyethylene Geomembranes
    Used in Exposed Temporary Applications” GRI GM 22, Geosynthetic Institute,
    Folsom, PA.
1.03 Submittals

Documents to be included in a submittal to the owner/engineer:

  1. 1. Example material warranty and Geomembrane installation warranty.
  2. 2. Sample of Geomembrane(s) to be installed including the technical data of the product.
  3. 3. Reports of the results of examinations and testing shall be prepared and submitted to
    the Owner’s Representative.
  4. 4. Shop drawings/panel layout for Geomembranes with panel numbers, field seam locations,
    corresponding to shipping labels.
  5. 5. Submit resumes or qualifications of the installation supervisor and certified welding
    technicians. It is recommended that the welding technicians hold an International
    Association of Geosynthetic Installers (IAGI) Certified Welding Technician (CWT) certification.
  6. 6. The documentation to be submitted by the Fabricator varies depending on the Owner’s
    requirements. These may include copy of tested seams, certifications, or any
    other document related to the quality of the Geomembranes and their installation.
  7. 7. Fabricator and Installer QC Manuals.

Part 2 – Products

2.01 Geomembrane Materials

Geomembranes Included:
This Document is an installation guideline for Factory Fabricated Fabric Supported Lightweight
Geomembranes that are less than or equal to 25 mil or 0.64 mm in thickness (as
measured by ASTM D5199, D751 or D1777). The top and bottom coating material of the geomembranes
included in this guideline may be comprised of a single or composite of the following
Polymers (in alphabetical order).

  • Low density polyethylene (LDPE)
  • Linear low density polyethylene (LLDPE)
  • High density polyethylene (HDPE)
  • Polyethylene (PE)
  • Polypropylene (PP)

Geomembranes that are included in this Guideline are the following:

  • Woven Coated Fabrics: These materials are woven flat tapes coated with a polymeric
    layer on both sides to create a geomembrane. The geomembrane may include one or
    more layers or arrangements of flat tapes and as many polymeric layers as needed to
    create a low hydraulic conductivity (relatively impermeable) structure. The finished
    sheet shall be capable of being thermally heat welded, fused or adhesively bonded to
    itself.
  • Woven Scrim Reinforced Geomembranes: This geomembrane has an internal lightweight
    open weave reinforcement consisting of woven yarns in a square pattern (i.e. 9 x
    9 or 10x 10 per sq. inch). The finished sheet shall be capable of being thermally heat
    welded, fused or adhesively bonded to itself.
  • String Reinforced Geomembranes: This geomembranes have a string reinforcement that
    has an open weave of greater than one-quarter inch (¼” or 8 mm) between fibers. The finished sheet shall be capable of being thermally heat welded, fused or adhesively
    bonded to itself. Thin gauge String Reinforced geomembrane materials <25 mils are included in this guideline if they are primarily repaired with techniques other than extrusion welding.

2.02 Quality Control

  1. a. Manufacturer’s Qualifications
    The manufacturer of the specified geomembrane or similar product shall have at least five
    years of continuous experience in the manufacture of the geomembrane. Additionally, the
    Manufacturer shall have produced a minimum of 2,000,000 m2 (21,527,820 ft2) of the specified
    geomembrane or similar product during the last 5 years.
  2. b. Fabricators Qualifications
    The fabricator of the geomembrane shall have fabricated a minimum of 250,000 m2/year
    (2,691,000 ft2/year) of the specified type or similar geomembranes.
  3. c. Installer’s Qualifications
    The Geomembrane Installer shall be the Fabricator, approved Fabricator’s Installer, or an
    installer/contractor approved by the Owner’s Representative. The installer shall have a minimum
    experience level of 50,000 m2 (538,200 ft2) using the specified geomembrane.
    It is the responsibility of any of the aforementioned parties to select a Geomembrane Installer
    with the appropriate degree of experience, personnel, and equipment to accomplish the
    required quality standards.
2.03 Geomembrane Arrival at Project Site
  1. a. Geomembrane Unloading
    Inspect fabricated geomembrane panels prior to unloading from vehicle at project site (e.g.
    type of material, conditions, etc.). Make any claims for damage with the carrier prior to unloading
    or shortly after geomembrane unloading.
    Materials delivered to site should be off-loaded (using forklift or similar equipment) in a location
    where minimum handling steps will be required.
    While unloading or transferring the fabricated panels from one location to another, prevent
    damage to the wrapping and the fabricated panel itself.
    Any damage during offloading and transferring should be documented by the contractor unloading
    the material and the installer.
  2. b. Storage
    Leave the panels packaged in UV protected wrap until the day that the panels are to be installed.
    If extremely hot or cold temperatures are present, keep the panels inside at a moderate
    temperature. This reduces the force required to unfold the panels.
    Fabricated panels, when possible, should be stored on pallets off the ground. The storage
    area should be dry, level, and with a firm base to facilitate lifting; so the panels are not
    damaged, do not become dirty, and remain dry externally and internally.

Part 3 – Execution

3.01 Installation

a. Subgrade Preparation
A pre-installation inspection shall be requested by the geomembrane installer and ALL interested
parties before moving panels from the storage location to the placement area. If the
subgrade is deemed to be inappropriate for any reason, it should be remediated prior to geomembrane
movement and placement.

Subgrade surfaces should be free of loose rock fragments (>10 mm or 0.4 inches), sticks,
sharp objects, or debris of any kind. The surface should provide a smooth, flat, firm, unyielding
foundation for the geomembrane with no sudden, sharp or abrupt changes or break
in grade that can tear or damage the geomembrane.

No standing water, mud, vegetation, snow, frozen subgrade, or excessive moisture is allowed
before geomembrane placement.

All pipes, drains, fitting, etc., which are to be installed beneath the geomembrane, should
be in place, backfilled, and ready to be covered with the geomembrane before panel deployment.
An anchor trench in the shape of a “U” or “V” can be used as a perimeter termination point
for the geomembrane. Installation of the geomembrane shall be started from the anchor
trench.

b. Unfolding and Deploying Prefabricated Panels
The geomembrane shall be supplied as a continuous panel with factory seams in the panel to reduce the amount of field seaming and testing.

Fabricated geomembrane panels are normally placed at a starting point on one corner of the
area to be lined. The deployment markings on the packaging or label indicate which direction
the panel will unfold. Note accordion-folded and rolled panels will unroll in only one principal
direction while double accordion-folded panels may unfold in either principal direction.

While unrolling and/or unfolding the geomembrane, inspect the fabricated panel for proper
material type and thickness, damage, and/or defects. Repair any damage found.

Provide suitable wind uplift protection with sandbags (dirt) or other ballast (such as rolls of
geotextile) after the geomembrane panel is unfolded.

Only material that is to be immediately welded, i.e., during that work-day, should be deployed.
Once the geomembrane is properly placed, the material should be seamed as soon as practical.

c. Field Seaming
A large advantage of factory fabricated geomembranes is that manufactured rolls of material
can be fabricated into large panels in a factory before shipment to the project site. This minimizes
the amount of the field seaming and maximizes the amount of factory seaming which
results in more high quality seams. In particular, the individual widths of the manufactured
geomembrane rolls shall be assembled into large panels that are custom-designed for the specific
project and correspond to the panel layout diagram. If factory seaming is maximized,
field seaming can be reduced by 80 to 95 %. In other words, only 5 to 20% of all seams need to
be made in the field depending on the unit weight of the geomembrane material. This reduction in field seaming improves seam quality, accelerates construction, minimizes or eliminates
destructive field seam tests, reduces weather exposure issues, allows modular construction,
and reduces project costs.

Field Cleaning of Seams
After the panels are initially placed in the proper position, remove as many wrinkles as practical.
If possible, allow the panels to “relax” by allowing the panel to warm in the sun. The
edges to be seamed need to be smooth and free of wrinkles to ensure good field seams and
no “fish mouths.”

An overlap of 0.15m (6 inches) for thermal seaming and 100 – 150 mm (4 – 6 inches) for tape
seaming must be cleaned of all dust, dirt, water, and foreign debris no more than 30
minutes prior to the seaming operation. Only clean, soft rags should be used for cleaning the
areas to be seamed.

The seaming operation requires a solid, dry, smooth subsurface (see section 3.01 A Subgrade
Preparation).

During the cleaning operation, the Geomembrane sheets will be inspected for proper type,
thickness, and defective areas which must be removed and/or repaired prior to seaming.

Field Seaming
Lightweight reinforced geomembranes are mainly used as a containment barrier for water or
other liquids (see Section 1.01 C above). For this reason, seaming the geomembranes is a
vital factor in the installation process.

For most projects, field seams should be run perpendicular to the slope.

Reinforced Factory Fabricated Lightweight Geomembrane Panels can be field seamed by either
of the following methods:

  1. Field Thermal Seaming (automated hot edge or hot air welding machine)
  2. Field Tape Seaming

Extrusion welding is not included in the field seaming list because it is not recommended for
geomembranes less than 40 mil (1.0 mm) thick.

Field Thermal Seaming (solid wedge only)
Thermal seaming is performed with an automated hot wedge or hot air welding machine,
which uses a heated element to melt the geomembranes to be welded and then presses the
two melted sheets together to form a fusion bond. When performed properly, wedge welders
produce high quality and consistent seams.

The wedge in a hot wedge welder can be heated with hot air (hot air method), or with electric
resistance heating (hot wedge method). It is common to weld fabric supported material
with a hot air wedge welder. All wedge welders employ a set point controller to accurately
maintain the welding temperature within the most efficient welding temperature for the
material. The pressure wheels are normally adjustable to allow for good material bonding
after heating.

The single (or solid) wedge arrangement produces a fully bonded weld not less than 25 mm
(1 inch) in width.

Seaming with a wedge welder is to be undertaken only by persons that have been trained
and qualified in the use of the equipment (see section 2.01 B above). Repairs, maintenance,
adjustments, and modifications are to be performed only by trained personnel.

Temperature controllers on the thermal welding device should be set according to type of
geomembrane, thickness, ambient temperature, type of heating (air v. wedge), rate of
seaming, and location of thermocouple within the device.

It is necessary for the operator to keep constant visual contact with the temperature controls,
as well as the completed seam exiting the welder to ensure adequate welding is occurring.
It is not recommended to adjust welding parameters without the approval of a trial
seam (See section 3.01.D.1 below).

Pre-heating of the geomembrane in the seaming area is optional. The amount or type of preheating
and its timing preceding the actual seaming is at the option of the installer.

Properly functioning portable electric generators must be available within close proximity of
the seaming region and with adequate extension cords to complete the entire seam. These
generators should be of sufficient size or number to handle all seaming electrical requirements.
The generator must have rubber tires, or be placed on a smooth plate such that it is
completely stable and it does not damage the geomembrane. Fuel (gasoline or diesel) for
the generator must be stored away from the geomembrane, and if accidentally spilled on
the geomembrane it must be removed immediately. The areas should be inspected for damage
to the geomembrane and repaired if necessary.

Field Tape Seaming
Prepared tapes include mastics, putties, asphalt, and butyl tapes can be used to seam some
geomembranes. Selection of the tape depends on the material being seamed and the fluid
being contained.

Immediately after creating a tape seam, it should be loaded or secured to facilitate bonding.
The preferred method for securing prepared tape joints is to backfill the geomembrane with a suitable soil cover so tensile stresses do not develop. The backfill creates a pressure seal
between the geomembrane panels and tape which is usually effective.

An alternative method of creating strength in a tape seam is to sew the seam first and then
use prepared tapes to waterproof the joint. Even with a sewn seam; the recommended practice
is to backfill the geomembrane to prevent shifting of the seam and to help adhere or
bond the tapes.

The minimum overlap of geomembrane sheets for tape seaming shall be about 0.10 m (4
inches).

Snow accumulations must be removed prior to seaming because tapes may not adhere or
stick in the presence of frost or dew.

To create a tape seam, place one or two continuous lines of prepared tape between the
sheet overlap. Press the sheet materials together to compress the tape using a rubber hand
roller or similar tool. In areas where wrinkles cannot be removed, use tapes on all sides of
the wrinkle to form a waterproof seal.

Visually inspect the completed seam to ensure intimate contact between the tapes and the
upper and lower sheet surfaces. Repair discontinuities by placing a patch over the damaged
area with a prepared tape seal around the perimeter. The patch must be round, oval, or
contain rounded corners and extend 0.15 m (6 inches) around the defect.

Supervise the backfilling of the seam area to prevent the seam from being pulled apart.
Backfill should proceed in a direction that does not tend to pull the seams apart or create a
shear or tensile stress in the seam. (See section 3.01G Cover Materials below).

d. Field Seaming Test Requirements

Test Seams (Trial Seams)
Test seams shall be prepared and tested by the Geomembrane Installer to verify that the
seaming parameters are adequate at the start of each welding session or at the beginning of
each working day.

Test seams also may be made whenever personnel or equipment are changed and when climatic
conditions reflect wide changes in geomembrane temperature or other conditions that
could affect seam quality.

A minimum of one test strip per seaming apparatus shall be conducted at the start of each
welding session during a day and at least every 4 hours or 3000 lineal feet of field seam per
machine, whichever is more frequent.

Test seams shall be made using “scrap” material from the same lot as the geomembrane being
welded in the field because the geomembrane is pre-fabricated into panels in a factory.
This requirement is necessary to ensure that the installed geomembrane panels are not damaged
prior to the onset of the field welding process because no destructive seam tests shall
be conducted on field welded seams to preserve integrity of the fabricated panels (See section
3.01.D.2.a below).

Test seaming shall be conducted under ambient conditions and with the same equipment,
geomembrane, and operator as field seaming on the fabricated panels. The test seams shall
be at least 1.8 m (6 ft) long for all types of field seams.

If there is no area or equipment on site to provide for these seam requirements, seam
strength can be verified for production using trial welds sent to an independent testing laboratory to verify quality.

If a test seam fails, an additional test seam shall be immediately completed. If the additional
test seam fails, the seaming apparatus shall be rejected and not used until the deficiencies
are corrected and a successful full test seam is produced.

Each test seam shall be labeled with date, geomembrane temperature, weather conditions,
number of seaming unit, panel identification, seam number or test location, technician performing
the test seam, and a pass or fail description.

Pre-qualification seams for tape seams shall be in accordance with ASTM D7272.

Non-Destructive Testing (NDT) of Seam Testing
All Field Seams shall be non-destructively tested by the Geomembrane Installer over the full
length of the seams before the seams are covered. Each seam shall be numbered or otherwise
designated. The location, date, test unit, name of the technician, name of QC person,
and outcome of all NDT shall be recorded and submitted to the Owner’s Representative.

Testing should be performed as the seaming progresses, not at the completion of all field
seaming, unless agreed to in advance by the Owner’s Representative. All defects found
should be repaired, re-tested, and remarked to indicate acceptable completion of repair.
NDT shall be performed using one or more of the following methods:

Air Lance Testing (ASTM D 4437)
The Geomembrane Installer shall provide an air compressor, air hose, and air lance wand
with a pressure gauge capable of measuring air flow to the tip. The testing shall be performed
by experienced technicians familiar with this testing procedure.

This non-destructive test involves placing the air lance wand 6 to 12 mm (¼ to ½ inch), but
not more than 50 mm (2 inches), from the edge of a completed seam and closely monitoring
the backside of the sheet for any air penetration through the seam, loose edges, riffles,
and/or noise. If air penetrates the seam area, the technician will either see this visibly or
hear it audibly and the area shall be marked for repair.

Mechanical Point Stress or “Pick” test (ASTM D4437)
This NDT uses a dull tool (such as a blunt screwdriver) under the top edge of a field seam.
With care, an installer can detect an un-bonded area, which is easier to separate than a
properly bonded area. Care should be taken to not damage the already bonded areas. This
method must be used with extreme care so as not to damage the parent thin gauge geomembrane
and is to be used only if other NDT methods are not available.

Identification of Defects
Seams shall be inspected by the geomembrane installer and the owner’s representative before,
during, and after field seaming to identify all dirty and wrinkled areas and any defects.

Evaluation of Defects

  1. i. Each suspect location (both in geomembrane seam and non-seam areas) shall be
    non-destructively tested. Each location which fails non-destructive testing shall
    be marked, numbered, measured, and posted on the daily installation drawings
    and subsequently repaired.
  2. ii. Defective seams, tears or holes shall be repaired by capping or cutting out the
    defective seam and re-seaming. Single seams in excess of 20% of their length requiring
    repair should be entirely removed and re-welded.
  3. iii. Each patch or capping shall extend a minimum of 150 mm (6 inches) in all directions
    beyond the defect.

e. Geomembrane Penetrations
Any structure or containment area built from man-made materials (metal, concrete, etc.)
shall not allow protrusions, pinch points, or movement of the supporting structure that
might damage the geomembrane and adversely affect the ability of the geomembrane to
perform its containment function. All pipes, drains, fitting, etc., which are to be installed
beneath the geomembrane, should be in place and ready to be covered with the geomembrane
before geomembrane deployment. If possible, avoid cutting the geomembrane at details
by using factory fabricated pipe boots that can be seamed to panels in the field. The
following directions provide additional details for handling geomembrane penetrations:

i. Pipes
Whenever possible, avoid slitting geomembrane panels for piping details until a prefabricated
pipe boot is ready for immediate installation. Cuts made in the geomembrane for
clearance over penetrations should always be made as small as possible to minimize
patch work. Generally, it is preferred to let the geomembrane straddle a relatively small
protrusion (for later detail work) provided that a rag or towel is taped over the pipe to
avoid damage to the geomembrane.

Factory prepared pipe boots should fit snugly but not require excessive force to pull over
a pipe. If a pipe boot feels overly snug but workable, try applying either talc powder or
using compressed air with a nozzle to float the boot sleeve over and along the pipe.

Pipe boots should never be used if the force required to install them stresses or weakens
the boot. When properly installed, the pipe boot will lay flat against grade surrounding
pipe without leaving pockets that may become stressed during or after placement of
backfill.

Pipe boot aprons should be seamed to the parent geomembrane using one of the repair
techniques described in the Seaming Section above (see 3.01C Field Seaming).

Proper leak proof sealing of pipe boots should be verified by non-destructive methods
(see section 3.01 D). The pipe boot sleeve should be attached to the pipe using butyl
tape between the pipe and boot and two stainless steel band clamps.

When cover materials are not used (see section 3.01.F below), splash pads or additional
geomembrane layers shall be used for all inflow pipes to prevent long term wear and
damage to the geomembrane caused by the direct impact of the inflow on the geomembrane
panels. The pads should be welded on top of the geomembrane panels and tested
according to sections 3.01.C and D, respectively. Common splash panel sizes are 1.2 to
1.8m (4 to 6 ft) in all directions. However, larger sizes may be required depending on the
amount of inflow pipes and the height to the discharge point.

ii. Concrete
Where bonding a geomembrane to concrete (or masonry) is required, the concrete surface
should be smooth, clean, dry, and free of any sharp protrusions or rock in the backfill.
Geomembrane to concrete seals shall be accomplished with mechanical anchors (e.g.
fasteners, termination bars). An approved sealant is placed between the geomembrane
and the concrete surface to ensure sealing.

The geomembrane fixed to a concrete structure must be on firm soil subgrade that will
not deform and stretch the geomembrane. Compacting of the soil subgrade around such
structures must be performed with particular care so excessive differential movement
between the concrete and soil subgrade does not occur.

iii. Drains
The geomembrane shall be mechanically fastened to the concrete structure at the location
of water discharge. This detail requires the installation of a concrete base or structure
at the location of the drain.

Where water enters or exits the geomembrane area, e.g., ponds, reservoirs, and canals,
this point must have proper geomembrane termination so as not to damage the geomembrane.
The area of inflow must be anchored with a trench of a depth or attached to a
structure as designed by the Project Engineer or Design Professional. The geomembrane is
installed and then anchored to the concrete prior to the covering with soil.

iv. Aerators
Geomembrane design in lagoons with aerators should require ballast, e.g. precast concrete
slab, on the geomembrane to prevent uplift and to provide a pad to support the aerator when
the water level is lowered. Many examples exist of geomembrane damage due to an aerator
settling on the geomembrane or where the geomembrane was lifted into the aerator. Other
aerator damage is frequently evidenced as cuts in the geomembrane along a specific elevation
on the side slope where the aerators have been pulled to shore for maintenance. Geomembrane
sheets are easily damaged by the sharp edges of a 6 mm (0.25 inch) thick stainless steel
plate of an aerator.

f. Cover Materials
When placing cover material or initially filling the containment area, it is important to ballast
the geomembrane into the perimeter anchor trench before covering or filling. The anchor
trench or perimeter shelf area should be the last area covered to complete the cover process.

Under all operating conditions, protection of the geomembrane will be required. Care should
be taken when covering the geomembrane to prevent any damage. At no time will construction equipment be allowed to operate or drive directly on the geomembranes.

Any damage to the geomembrane should be repaired prior to proceeding with cover material
placement. Costs associated with repairs are the general contractor’s responsibility.
The cover material shall be placed as soon as practical, in conjunction with or upon completion
of the geomembrane installation or as the installation progresses to minimize traffic on
the geomembrane and damage.

Access roads for clean soil cover should be maintained to provide 0.3 m (12 inch) minimum
and for heavier equipment on haul roads a minimum of 0.45 m (18 inch) preferable between
the excavation equipment and geomembrane at all times. Some geomembrane manufacturers
may require a soil or a sand cover of at least 0.45 m (18 inches), so cover soil requirements
should be verified before placement with the Design Professional and geomembrane
fabricator.

Heavy equipment should operate on a minimum 1 m (3-foot) thick roadway where the “haul
road” is established in and out of the containment area.

Cover material shall consist of 12 mm (0.5 inch) minus particles, clean rounded soils or gravels
free of sharp edges, sticks, metal, rubbish, and debris or foreign materials. Site specific
materials or sizes may be acceptable. It is recommended that the contractor receive prior
written approval of acceptance of the cover materials from a geomembrane representative
and/or Design Professional before covering the geomembrane.

Cover soils should be dumped and leveled over the geomembrane and not pushed from one end to the other to minimize rolling and wrinkling of the geomembrane beneath the soils.

Cover soil should always be placed from the bottom to the top of slopes to avoid stressing
the geomembrane and slope stability problems.

Equipment should be turned in long sweeping turns and not spun quickly to eliminate the
chance of tires digging down to the geomembrane thru the cover soil and wrinkling or
stretching the geomembrane.

If geomembrane damage does occur during construction, cover placement, and/or filling, DO
NOT COVER IT UP. Advise the foreman and CQA personnel so repair can be made and documented
which will make doing the repair a lot easier than after cover soil placement or filling.

g. Field Acceptance
The Geomembrane will be accepted by the Owner’s Representative when all of the following
have been completed:

    1. The entire installation is finished or on agreed upon subsections of the installation
    are finished (3.01 A through 3.01F).
    2. All Installer’s QC documentation is complete and submitted to the Owner.
    3. Verification of the adequacy of all field seams and repairs and associated geomembrane
    testing is complete.

h. Site Clean Up and Demobilization
On completion of installation, the geomembrane installer shall dispose of all waste and scrap
material in a location provided and approved by the owner. The installer should also remove
all equipment used in connection with the work herein, and shall leave the premises in a
neat and acceptable manner. No scrap material shall be left on the completed surface of the
geomembrane or in the anchor trenches.

Part 4 – Measurement and Payment

4.01 Measurement and Payment

As per project specifications.


Factory Fabricated Heavyweight > 0.64 mm (25 mil) Thickness Fabric-Supported Geomembranes

Download PDF

Part 1 – General

1.01 Guideline Scope

A. This document is an installation guideline for Factory Fabricated Fabric-
Supported Heavyweight Geomembranes (>0.64 mm or 25 mil in thickness
as measured by ASTM D5199, D751 or D1777). The applicable product
types are as outlined in Part 2 of this guideline. This guideline is designed
to provide a minimum set of standards for site installation. However,
depending on the complexity and project specific requirements, a
qualified design engineering firm may be require different design and installation
procedures for the geomembrane. All work shall be in accordance
with the project drawings, specifications and QC requirements.

B. Applications
Typical applications for factory fabricated Fabric-Supported Heavyweight Geomembranes
that are more than 0.64 mm (25 mil) in thickness include but are not
limited to:

  • Irrigation and canal liners
  • Landfill liners
  • Leach pad liners
  • Moisture barriers and covers for athletic fields
  • Golf course and decorative pond liners
  • Soil remediation pads
  • Interim and final landfill and Mine Reclamation cover systems
  • Shale oil and gas development, e.g., drill pads and various liquid containment
  • Oil and gas production, e.g., various secondary containment applications
  • Mining leach pads and various liquid containment and transport applications
  • Tailings ponds
  • Water reservoirs and ponds
  • Paved and unpaved roadways
  • Subgrade protection
  • Temporary erosion control
  • Barriers, blankets, and curtains
  • Rain sheets for Ore in Mining Applications
  • Underslab vapor retarders
1.02 References

American Society for Testing and Materials (ASTM)

  1. 1. ASTM D4437. “Standard Practice for Non-destructive Testing (NDT) for Determining
    the Integrity of Seams Used in Joining Flexible Polymeric Sheet Geomembranes”.
    ASTM International, West Conshohocken, PA.
  2. 2. ASTM D5199. “Standard Test Method for Measuring the Nominal Thickness of Geosynthetics”.
    ASTM International, West Conshohocken,
    PA.
  3. 3. ASTM D751. “Standard Test Methods for Coated
    Fabrics”. ASTM International, West Conshohocken,
    PA.
  4. 4. ASTM D1777. “Standard Test Method for Thickness
    of Textile Materials”. ASTM International,
    West Conshohocken, PA.
  5. 5. ASTM D5641. “Standard Practice for Geomembrane
    Seam Evaluation by Vacuum Chamber”.
    ASTM International, West Conshohocken, PA.

Other References

  1. 1. USEPA. (1991). Inspection Techniques For The Fabrication Of Geomembrane Field Seams. Cincinnati, Ohio 45268: U.S. Environmental
    Protection Agency.
  2. 2. Koerner, R. M. (2005). Designing with Geosynthetics (5 ed.). Upper Saddle River,
    NJ 07458: Pearson Education, Inc.
  3. 3. Geosynthetic Research Institute (2012). “Standard Specification for Test Methods,
    Required Properties and Testing Frequencies for Scrim Reinforced Polyethylene
    Geomembranes Used in Exposed Temporary Applications” GRI GM 22, Geosynthetic
    Institute, Folsom, PA.
  4. 4. Scheirs, J. (2009). A Guide to Polymeric Geomembranes. John Wiley & Sons.
    doi:10.1002/9780470748213.
  5. 5. GRI GM 14, Test Frequencies for Destructive Seam Testing Selecting, variable
    intervals for taking geomembrane destructive samples using the method of attributes.
1.03 Submittals

Documents to be included in a submittal to the owner/engineer for review
or approval:

  1. 1. Example material warranty and Geomembrane installation warranty.
  2. 2. Sample of Geomembrane(s) to be installed including the technical data on the
    product.
  3. 3. Reports on the results of examinations and
    testing shall be prepared and submitted to
    the Owner’s Representative.
  4. 4. Shop drawings/panel layout for Geomembranes
    with panel numbers, field seam locations
    and details, corresponding to shipping
    labels.
  5. 5. Submit resumes or qualifications of the installation supervisor and certified welding
    technicians.
  6. 6. Documentation of manufacturer’s and installer’s qualifications (see section 2.02
    below). It is recommended that the welding technicians hold an International
    Association of Geosynthetic Installers (IAGI) Certified Welding Technician (CWT)
    certification in reinforced geomembranes
  7. 7. The installer shall submit a list of at least ten completed facilities. For each installation,
    provide: name and type of facility; its location; the date of installation;
    name and telephone number of contact at the facility; type and thickness
    of geomembrane and; surface area of the installed geomembrane.
  8. 8. The documentation to be submitted by the Fabricator to the Owner varies depending
    on the Owner’s requirements. Documentation may include copies of
    tested seam results, certifications, or any other document related to the quality
    of the geomembranes and their installation.
  9. 9. Fabricator and Installer QC Manuals.

Additional submittals (at Completion)

  1. 1. Geomembrane installation warranty. The installer shall guarantee the geomembrane
    installation against defects in the installation and workmanship for one
    (1) year commencing with the date of final acceptance.
  2. 2. Compilation of pre-qualification test seam samples reports (see section 3.01.D.1
    below).
  3. 3. Compilation of destructive and non-destructive field seam tests reports (See
    section 3.01.D below).

Part 2 – Products

2.01 Geomembrane Materials

Geomembranes included

  1. 1. This Document is an installation guideline for Factory Fabricated Fabric-
    Supported Heavyweight Geomembranes that are more than 0.64 or mm 25 mil in
    thickness (as measured by ASTM D5199, D751 or D1777). The top and bottom coating
    material of the geomembranes included in this guideline may be comprised of
    a single layer or composite of the following Polymers (in alphabetical order).
    • Chlorosulfonated Polyethylene (CSPE)
    • Ethylene Interpolymer Alloy (EIA)
    • Low density polyethylene (LDPE)
    • Linear low density polyethylene (LLDPE)
    • High density polyethylene (HDPE)
    • Polyethylene (PE)
    • Polypropylene (PP)
    • Polyurethane (PU)
    • Polyvinyl Chloride (PVC)

    Geomembranes that are included in this Guideline are the following:

    • Woven Coated Fabrics: These materials are woven flat tapes coated with a
      polymeric layer on both sides to create a geomembrane. The geomembrane
      may include one or more layers or arrangements of flat tapes and as many polymeric
      layers as needed to create a low hydraulic conductivity (relatively impermeable)
      structure. The finished sheet shall be capable of being thermally
      heat welded, fused, or adhesively bonded to itself.
    • Woven Scrim Reinforced Geomembranes: This geomembrane has an internal
      lightweight open weave reinforcement consisting of woven yarns in a square pattern (i.e., 3.6 x 3.6 or 4 x 4 per sq. cm or 9 x 9 or 10 x 10 per sq. inch). The
      finished sheet shall be capable of being thermally heat welded, fused, or adhesively
      bonded to itself.
    • String Reinforced Geomembranes: This geomembrane has a string reinforcement
      that has an open weave of greater than one-quarter inch (8 mm or ¼
      inch) between fibers. The finished sheet shall be capable of being thermally
      heat welded, fused, or adhesively bonded to itself.
    2.02 Quality Control

    A. Manufacturer’s Qualifications
    The manufacturer of the specified geomembrane or similar product shall have
    at least five years of continuous experience in the manufacture of the geomembrane.
    Additionally, the Manufacturer shall have produced a minimum of
    2,000,000 m2 (21,527,820 square feet) of the specified geomembrane or similar
    product during the last 5 years.

    B. Fabricators Qualifications
    The fabricator of the geomembrane shall have fabricated a minimum of 500,000 m2/
    year (5,381,955 ft2/year) of the specified type or similar geomembranes.

    C. Installer’s Qualifications
    The Geomembrane Installer shall be the Fabricator, approved Fabricator’s Installer,
    or an installer/contractor approved by the Owner’s Representative. The geomembrane
    installer shall have installed at least 10 projects involving a total of
    500,000 m2 (5,381,955 ft2) using the specified geomembrane. It is the responsibility of any of the aforementioned parties to select a Geomembrane
    Installer with the appropriate degree of experience, personnel, and equipment
    to accomplish the required quality standards.

    2.03 Geomembrane Arrival at Project Site

    A. Geomembrane Unloading

    1. 1. Inspect fabricated geomembrane panels prior to unloading from vehicle at project
      site (e.g. type of material, conditions, etc.). Make any claims for damage
      with the carrier prior to unloading or shortly after geomembrane unloading.
    2. 2. Materials delivered to site should be off-loaded (using forklift or similar equipment)
      in a location where minimum handling steps will be required.
    3. 3. While unloading or transferring the fabricated panels from one location to another,
      prevent damage to the wrapping and the fabricated panel itself.
    4. 4. Any damage during offloading and transferring should be documented by the
      contractor unloading the material and the installer.

    B. Storage

    1. 1. Leave the panels packaged in UV protected wrap until the day that the panels
      are to be installed. If extremely hot or cold temperatures are present, keep the
      panels inside at a moderate temperature. This reduces the effort required to
      unfold the panels.
    2. 2. Fabricated panels, when possible, should be stored on pallets off the ground.
      The storage area should be dry, level, and with a firm base to facilitate lifting; so the panels are not damaged, do not become dirty, and remain dry externally
      and internally.

    Part 3 – EXECUTION

    3.01 Installation

    A. Subgrade Preparation

    1. 1. A pre-installation inspection shall be requested by the geomembrane installer and
      ALL interested parties before moving panels from the storage location to the placement
      area. If the subgrade is deemed to be inappropriate for any reason, e.g.,
      roughness, moisture, rock, etc., it should be remediated prior to geomembrane
      movement and placement.
    2. 2. The geomembrane installer and owner’s representative shall provide daily written
      acceptance for the surface to be covered by the geomembrane in that day’s operations.
    3. 3. Subgrade surfaces should be free of loose rock fragments (>10 mm or 0.4 inches),
      sticks, sharp objects, or debris of any kind. The surface should provide a smooth,
      flat, firm, unyielding foundation for the geomembrane with no sudden, sharp or
      abrupt changes or break in grade that can tear or damage the geomembrane.
    4. 4. No standing water, mud, vegetation, snow, frozen subgrade, or excessive moisture
      is allowed before geomembrane placement.
    5. 5. All pipes, drains, fitting, etc., which are to be installed beneath the geomembrane,
      should be in place, backfilled, and ready to be covered with the geomembrane
      before panel deployment.
    6. 6. An anchor trench in the shape of a “U” or “V” can be used as a perimeter termination
      point for the geomembrane. Installation of the geomembrane shall be
      started from the anchor trench.

    B. Unfolding and Deploying Prefabricated Panels

    1. 1. The geomembrane shall be supplied as a continuous, factory-seamed panel to
      reduce the amount of field seaming and testing.
    2. 2. The geomembrane shall be installed to the limits shown on the project drawings
      and essentially as shown on approved panel layout drawings.
    3. 3. Fabricated geomembrane panels are normally placed at a starting point on one
      corner of the area to be lined. The deployment markings on the packaging or
      label indicate which direction the panel will unfold. Note accordion-folded and
      rolled panels will unroll in only one principal direction while double accordionfolded
      panels may unfold in either principal direction.
    4. 4. While unrolling and/or unfolding the geomembrane, inspect the fabricated panel
      for proper material type and thickness, damage, and/or defects. Repair any
      damage found.
    5. 5. Provide suitable wind uplift protection with sandbags (dirt) or other ballast
      (such as rolls of geotextile) after the geomembrane panel is unfolded.
    6. 6. Only material that is to be immediately welded, i.e., during that work-day,
      should be deployed.
    7. 7. Once the geomembrane is properly placed, the material should be seamed as
      soon as practical.

    C. Field Seaming

    1. 1. A large advantage of factory fabricated geomembranes is that manufactured rolls of material can be fabricated into large panels in a factory before shipment
      to the project site. This minimizes the amount of the field seaming and maximizes
      the amount of factory seaming which results in more high quality seams. In
      particular, the individual widths of the manufactured geomembrane rolls shall
      be assembled into large panels that are custom-designed for the specific project
      and correspond to the panel layout diagram. If factory seaming is maximized,
      field seaming can be reduced by 80 to 95 percent. In other words, only 5 to 20%
      of all seams need to be made in the field depending on the unit weight of the
      geomembrane material. This reduction in field seaming improves seam quality
      by seaming in controlled conditions, accelerates construction, minimizes or
      eliminates destructive field seam tests, reduces weather exposure issues, allows
      modular construction, and reduces project costs.
    2. 2. Field Cleaning of Seams
      1. a. After the panels are initially placed in the proper position, remove as many
        wrinkles as practical. If possible, allow the panels to “relax” by allowing the
        panel to warm in the sun before seaming. The edges to be seamed need to
        be smooth and free of wrinkles to ensure good field seams and no “fish
        mouths”.
      2. b. A minimum overlap of 100 mm to 150 mm (4 – 6 inches) for all field seams
        types, e.g., thermal fusion, tape, chemical fusion, etc., must be cleaned of
        all dust, dirt, water, and foreign debris no more than 30 minutes prior to the
        seaming operation. Only clean, soft rags should be used for cleaning the areas
        to be seamed.
      3. c. The seaming operation requires a solid, dry, smooth subsurface (see section
        3.01 A Subgrade Preparation).
      4. d. During the cleaning operation, the Geomembrane sheets will be inspected for
        proper type, thickness, and defective areas which must be removed and/or
        repaired prior to seaming.
    3. 3. Field Seaming:
      1. a. Reinforced Factory Fabricated Heavyweight Geomembrane Panels can be
        field seamed by one or more of the following methods:
        1. i. Thermal Fusion Welding
        2. ii. Extrusion Welding
        3. iii. Chemical Fusion Welding
        4. iv. Adhesive Bonding
        5. v. Field Tape Seaming
    4. 4. Thermal Fusion Welding:
      1. a. Wedge welding is performed with a hot wedge welding machine, which uses
        a heated element to melt the geomembranes to be welded and then presses
        the two melted sheets together to form a fusion bond. When performed
        properly, wedge welders produce high quality and consistent seams.
      2. b. The wedge in a hot wedge welder can be heated with hot air (hot air method),
        or with electric resistance heating (hot wedge method). It is common to
        weld fabric supported material with a hot air wedge welder. All wedge
        welders employ a set point controller to accurately maintain the welding
        temperature within the most efficient welding temperature for the material.
        The pressure wheels are normally adjustable to allow for good material
        bonding after heating.
      3. c. Only single or solid wedge arrangement is available for factory and field
        welding of Reinforced Heavyweight Geomembranes. Only single or solid
        wedge welding should be used for factory and field welding because of the
        presence of scrim or tape exposures in the completed seams. These exposures
        can result in false pressure drops in completed seams that make a resulting
        air-channel test unreliable. The single (or solid) wedge arrangement
        produces a continuous bonded weld not less than 25 mm (1″ inch) width. A
        double (or split) wedge produces two welds with an un-bonded channel between
        them. This channel is intended for use in non-destructive air pressure
        testing; however, air lance and pick tests may also be used on split wedge
        welded seams as well (See Section 3.01.D below). However, difficulties may
        be encountered air pressure testing as noted above so only single or solid
        wedge welding should be used for factory and field welding.
      4. d. Seaming with a wedge welder is to be undertaken only by persons that have
        been trained and qualified in the use of the equipment (see section 2.02C
        above). Repairs, maintenance, adjustments, and modifications are to be
        performed only by trained personnel.
      5. e. Temperature controllers on the thermal welding device should be set according
        to type of geomembrane, thickness, ambient temperature, type of
        heating (air v. wedge), rate of seaming, and location of thermocouple within
        the device.
      6. f. It is necessary for the operator to keep constant visual contact with the
        temperature controls, as well as the completed seam exiting the welder to
        ensure adequate welding is occurring. It is not recommended to adjust welding
        parameters without first constructing and testing a trial seam. If the
        trail seam meets minimum acceptable values, the adjustments can be used
        on the field seam (See section 3.01.D.1 below).
      7. g. Pre-heating of the geomembrane in the seaming area is optional. The
        amount or type of preheating and its timing preceding the actual seaming is
        at the option of the installer.
      8. h. Properly functioning portable electric generators must be available within
        close proximity of the seaming region and with adequate extension cords to
        complete the entire seam. These generators should be of sufficient size or
        number to handle all seaming electrical requirements. The generator must
        have rubber tires, or be placed on a smooth plate such that it is completely
        stable and it does not damage the geomembrane. Fuel (gasoline or diesel)
        for the generator must be stored away from the geomembrane, and if accidentally
        spilled on the geomembrane it must be removed immediately. The
        areas should be inspected for damage to the geomembrane and repaired if
        necessary.
    5. 5. Extrusion Welding
      1. a. In extrusion welding, a fusion joint is created by applying a bead of heated
        and softened plastic on top of, (fillet seaming) or in between (flat seaming)
        the overlapped edges of the geomembrane panels to be seamed.
      2. b. Historically, extrusion welding has not been recommended for panel to panel
        production seams however some geomembranes such as reinforced LLDPE can
        be extrusion welded. Typically extrusion welding is used only on minor detail
        work, repairs and work around penetrations (see section 3.01.E) and cut
        scrim edges.
      3. c. Extrusion welding is not recommended for geomembranes thinner than
        0.762 mm (30 mils).
      4. d. All exposed cut scrim or fabric edges shall be encapsulated with an extrusion
        bead of the same polymer as the geomembrane.
      5. e. Extrusion welding is applicable to the following materials: EIA, HDPE, LLDPE,
        PE, PP, PU geomembranes.
      6. f. The minimum overlap for extrusion welding should be about 50 mm (2 inches).
      7. g. It is appropriate to grind the surfaces to be seamed prior to the application of
        the softened plastic bead. The roughened surface should be slightly narrower
        than the seam width.
      8. h. Grinding dust and grit should be cleaned prior to extrusion welding.
      9. i. Grinding should not remove more than 10% of geomembrane thickness.
      10. j. The quality of extrusion welding seams is affected by welding temperature,
        welding speed, applied preheat, bead thickness, and operator’s skills
    6. 6. Chemical Fusion Welding
      1. a. The materials described in this guideline (see section 1.01.A) applicable to
        chemical welding include: EIA, CSPE, and PVC geomembranes.
      2. b. Chemical fusion welding consists of the application of a chemical substance
        (Seam bonding solvents) at the surface of the strip of the geomembrane
        sheets that are going to be seamed. This chemical softens the geomembranes
        in contact and creates a viscous interface which is later subject to pressure
        to create a bond between the two geomembranes in contact.
      3. c. All field seams should overlap a minimum of 150 mm (6 inches) wide. A sufficient
        amount of chemical fusion agent should be applied that, upon compressing
        the seam surfaces together, a thin excess of chemical fusion agent is
        forced out of the seam. Enough time should be provided to make the chemical
        soften the surfaces of the geomembranes in contact before pressing them
        together.
      4. d. A high durometer rubber, nylon, or hand steel roller can be used to compress
        the seam surfaces together releasing any air bubbles until a bond is formed.
      5. e. Bodied chemical fusion is a special type of chemical welding, where a small
        quantity of the lining material (about 10%) is dissolved in the solvent to help
        reduce the amount of solvent used, to increase the viscosity of the chemical,
        and to speed evaporation of the solvent.
      6. f. Chemical solvents are designed to produce adhesive welds in compatible plastic
        films. Contact the geomembranes representative to determine the optimum
        bonding agent for the geomembrane being installed.
      7. g. A minimum overlap of 150 mm (6 inches) should be provided for chemical
        welding.
      8. h. Chemical seaming is a time dependent process. Enough time should be allowed
        prior to the execution of non-destructive testing.
    7. 7. Adhesive Bonding
      1. a. As with chemical welding, the materials described in this guideline (see section
        1.01.A) applicable to adhesive welding include: EIA, CSPE, and PVC geomembranes.
      2. b. Adhesive seams also consist of the application of a chemical substance. However,
        in adhesive seams, the chemical acts as a cementing material and does
        not soften the geomembrane sheets.
      3. c. A minimum overlap of 150 mm (6 inches) should be provided for adhesive
        seaming.
      4. d. Similar to chemical seaming, adhesive seaming is also a time dependent process
        and requires enough time to set up prior to the execution of the nondestructive
        testing.
    8. 8. Field Tape Seaming
      1. a. Some Factory Fabricated Fabric-Supported Heavyweight Geomembranes can
        be seamed using field tape seaming methods. Tape seaming is limited to 0.6
        mm (24 mil) and 0.76 mm (30 mil) woven coated or string reinforced geomembranes.
      2. b. Prepared tapes such as mastics, putties, asphalt, and butyl tapes can be used
        to seam some geomembranes. Selection of the tape depends on the material
        being seamed and the fluid being contained.
      3. c. Immediately after creating a tape seam, it should be loaded or secured to
        facilitate bonding. The preferred method for securing prepared tape joints is
        to backfill the geomembrane with a suitable soil cover so tensile stresses do
        not develop. The backfill creates a pressure seal between the geomembrane
        panels and tape which is usually effective.
      4. d. An alternative method of creating strength in a tape seam is to sew the seam
        first and then use prepared tapes to waterproof the joint. Even with a sewn
        seam; the recommended practice is to backfill the geomembrane to prevent
        shifting of the seam and to help adhere or bond the tapes.
      5. e. Ambient conditions for prepared tape seaming should be in accordance to
        manufacturer’s directions. Snow accumulations must be removed prior to
        seaming because tapes may not adhere or stick in the presence of frost or
        dew.
      6. f. To create a tape seam, place one or two continuous lines of prepared tape
        between the sheet overlap. Press the sheet materials together to compress
        the tape using a rubber, nylon, or steel hand roller or similar tool. In areas
        where wrinkles cannot be removed, use tapes on all sides of the wrinkle to
        form a waterproof seal.
      7. g. Visually inspect the completed seam to ensure intimate contact between the
        tapes and the upper and lower sheet surfaces. Repair discontinuities by placing
        a patch over the damaged area with a prepared tape seal around the perimeter.
        The patch must be round, oval, or contain rounded corners and extend
        150 mm (6 inches) around the defect.
      8. h. Supervise the backfilling of the seam area to prevent the seam from being
        placed in tension and pulled apart. Backfill should proceed in a direction that
        does not tend to pull the seams apart or create a shear or tensile stress in the
        seam. (See section 3.01G Cover Materials below).

    D. Field Seaming Test Requirements

    1. 1. Test Seams (Trial Seams)
      1. a. Test seams shall be prepared and tested by the Geomembrane Installer to
        verify that the seaming parameters meet accepted seam values at the start
        of each welding session or at the beginning of each working day.
      2. b. Test seams also may be made whenever personnel or equipment are changed
        and when climatic conditions reflect wide changes in geomembrane temperature
        or other conditions that could affect seam quality.
      3. c. A minimum of one test strip per seaming apparatus shall be conducted at the
        start of each welding session during a day and at least every 4 hours or 915
        lineal meters (3000 lineal feet) of field seam per machine, whichever is more
        frequent.
      4. d. Field test seams shall be made using “scrap” material from the same lot as
        the geomembrane being welded in the field because the geomembrane is pre
        -fabricated into panels in a factory. This requirement is necessary to ensure
        that the installed geomembrane panels are not damaged prior to the onset of
        the field welding process because no destructive seam tests shall be conducted
        on factory fabricated seams to preserve integrity of the fabricated panels
        (See section 3.01.D.2.a below).
      5. e. Test seaming shall be conducted under ambient conditions and with the same
        equipment, geomembrane, and operator as field seaming on the fabricated
        panels. The test seams shall be at least 1.8 meter (6 feet) long for all types
        of field seams.
      6. f. If there is no area or equipment on site to provide for these seam requirements,
        seam strength can be verified for production using trial welds sent to an
        independent testing laboratory to verify quality.
      7. g. If a test seam fails, an additional test seam shall be immediately completed. If
        the additional test seam fails, the seaming apparatus shall be rejected and not
        used until the deficiencies are corrected and a successful full test seam is produced.
      8. h. Each test seam shall be labeled with date, geomembrane temperature, weather
        conditions, number of seaming unit, panel identification, seam number or
        test location, technician performing the test seam, and a pass or fail description.
      9. i. Pre-qualification seams for tape seams shall be in accordance with ASTM
        D7272.
      10. j. There is a variance in the ASTM seam testing utilized for the geomembranes
        specified in this document. The Design Engineer should include the specific
        ASTM test methods that are relevant to the specified material.
    2. 2. Non-Destructive Testing (NDT) of Seam Testing
      1. a. ALL FIELD SEAMS shall be non-destructively tested by the Geomembrane Installer
        over the full length of the seams before the seam is covered. Each seam
        shall be numbered or otherwise designated. The location, date, test unit, name
        of the technician, name of QC person, and outcome of all NDT shall be recorded
        and submitted to the Owner’s Representative.
      2. b. Testing should be performed as the seaming progresses, not at the completion
        of all field seaming, unless agreed to in advance by the Owner’s Representative.
        All defects found should be repaired, re-tested, and remarked to indicate
        acceptable completion of repair.
      3. c. NDT of field seams shall be performed using one or more of the following
        methods:
    3. 3. Air Lance Testing (ASTM D 4437)
      1. a. The Geomembrane Installer shall provide an air compressor, air hose, and
        air lance wand with a pressure gauge capable of measuring air flow to the
        tip. The testing shall be performed by experienced technicians familiar with
        this testing procedure.
      2. b. This non-destructive test involves placing the air lance wand 6 to 12 mm (¼
        to ½ inch), but not more than 50 mm (2 inches), from the edge of a completed
        seam and closely monitoring the backside of the sheet for any air
        penetration through the seam, loose edges, riffles, and/or noise. If air penetrates
        the seam area, the technician will either see this visibly or hear it
        audibly and the area shall be marked for repair.
    4. 4. Vacuum Box Testing (ASTM D5641)
    5. NOTE: Vacuum box testing is not appropriate for all flexible products. Some
      flexible materials will pull up or adhere to the screen of the vacuum box and
      false values can result. Contact the material manufacturer for guidance on
      whether you should vacuum box test the geomembrane being used.
      1. a. Vacuum box testing is preferable for extrusion welding.
      2. b. Apply soapy solution to seam area to be tested.
      3. c. Place vacuum box with clean viewing glass along seam.
      4. d. Ensure sealing foam around bottom of box is well seated and provides a
        good seal.
      5. e. It may be necessary to “work” the box into place and to use some wet rags
        to get a good seal.
      6. f. Apply a minimum pressure in the box of about 27.6 kPa (4 psi) to test the
        seams.
      7. g. Monitor the seam for soap bubbles for at least 5 seconds.
      8. h. Mark any locations where bubbles indicate leaks for repairs.
      9. i. If no bubbles occur after 5 seconds, relieve vacuum and move to next seam
        section.
      10. j. An overlap of about 75 mm (3 inches) should be tested between two consecutive
        testing sections along the field seam being tested.
      11. k. With thinner products it may be beneficial to install a rigid mesh over the
        bottom of the box to prevent the geomembrane from being sucked or pulled
        into the vacuum box. Avoid rough edges that might damage the geomembrane.
    6. 5. Destructive Field Seam Testing
      1. a. One destructive test sample per 150 lineal meters (492 linear feet) of field
        seam length or another predetermined length in accordance with GRI GM 14
        shall be obtained by the Geomembrane Installer from a location specified by
        the Owner’s Representative. The Geomembrane Installer shall not be informed
        in advance of the sample location. Testing should be arranged such
        that test results are provided prior to completion of geomembrane installation.
        Samples shall be cut by the Geomembrane Installer as directed by the
        Owner’s Representative as seaming progresses.
      2. b. All field samples shall be marked with their sample number and seam number.
        The sample number, date, time, location, and seam number shall be
        recorded. The Geomembrane Installer shall repair all of the holes in the geomembrane
        created during the seam sampling process. All patches shall be
        vacuum box tested or spark tested to ensure no leakage. If a patch cannot be
        permanently installed over the test location the same day of sample collection,
        a temporary patch shall be tack welded or hot air welded over the
        opening until a permanent patch can be affixed.
      3. c. The destructive sample size shall be 300 mm (12 inches) wide by 1 m (39
        inches) long with the seam centered lengthwise. The sample shall be cut into
        three equal sections and distributed as follows: one section given to the
        Owner’s Representative as an archive sample; one section given to the Owner’s
        Representative for laboratory testing as specified in paragraph (e) below;
        and one section retained by the Geomembrane Installer for field testing as
        specified in paragraph (d) below.
      4. d. For field testing, the Geomembrane Installer shall cut replicate specimens
        from his sample in accordance with the ASTM test method appropriate to the
        geomembrane being installed. The Geomembrane Installer shall test five
        specimens for seam shear strength and five for seam peel strength. Peel tests
        will be performed on both inside and outside weld tracks. To be acceptable,
        4 of 5 test specimens must pass the specified Geomembrane Manufacturer’s
        strength criteria with less than 25% separation. If 4 of 5 specimens pass, the
        sample qualifies for testing by the testing laboratory if required.
      5. e. Standard ASTM non-destructive test (NDT) methods shall be used to evaluate
        seams. The Engineer shall designate the appropriate standard NDT method
        dependent on the type of geomembrane to be installed.
      6. f. Reports of the results of examinations and testing shall be prepared and submitted
        to the Owner’s Representative.
      7. g. For field seams, if a laboratory test fails, that shall be considered as an indicator
        of the possible inadequacy of the entire seamed length corresponding
        to the test sample. Additional destructive test portions shall then be taken
        by the Geomembrane Installer at locations indicated by the Engineer; typically
        3 m (10 feet) on either side of the failed sample.
      8. h. On either side of the failed sample and laboratory seam tests shall be performed.
        Passing tests shall be an indicator of adequate seams. Failing tests
        shall be an indicator of non-adequate seams and all seams represented by
        the destructive test location shall be repaired with a cap-strip extrusion
        welded to all sides of the capped area. All cap-strip seams shall be nondestructively
        vacuum box tested until adequacy of the seams is achieved.
        Cap strip seams exceeding 50 m (164 feet) shall be destructively tested.
      9. i. Destructive field seaming tests for tape seams (see section 3.01.C.3.f above)
        shall be in accordance with ASTM D7272.
    7. 6. Identification of Defects
      1. a. Seams shall be inspected by the geomembrane installer and the owner’s representative
        before, during, and after field seaming to identify all dirty and
        wrinkled areas and any defects.
    8. 7. Evaluation of Defects
      1. a. Each suspect location (both in geomembrane seam and non-seam areas) shall
        be non-destructively tested. Each location which fails non-destructive testing
        shall be marked, numbered, measured, and posted on the daily installation
        drawings and subsequently repaired.
      2. b. Defective seams, tears or holes shall be repaired by capping or cutting out
        the defective seam and re-seaming. Single seams in excess of 20% of their
        length requiring repair should be entirely removed and re-welded.
      3. c. Each patch or capping shall extend a minimum of 150 mm (6 inches) in all
        directions beyond the defect.
      4. d. All repairs shall be located, measured, non-destructively tested, and recorded.

    E. Geomembrane Penetrations
    Any structure or containment area built from man-made materials (metal, concrete,
    etc.) shall not allow protrusions, pinch points, or movement of the supporting structure
    that might damage the geomembrane and adversely affect the ability of the geomembrane
    to perform its containment function. All pipes, drains, fitting, etc., which are to
    be installed beneath the geomembrane, should be in place and ready to be covered with
    the geomembrane before geomembrane deployment. If possible, avoid cutting the geomembrane
    at details by using factory fabricated pipe boots that can be seamed to panels
    in the field. The following directions provide additional details for handling geomembrane
    penetrations:

    1. 1. Pipes
      1. a. Whenever possible, avoid slitting geomembrane panels for piping details until
        a prefabricated pipe boot is ready for immediate installation. Cuts made in
        the geomembrane for clearance over penetrations should always be made as
        small as possible to minimize patch work. Generally, it is preferred to let the
        geomembrane straddle a relatively small protrusion (for later detail work) provided
        that a rag or towel is taped over the pipe to avoid damage to the geomembrane.
      2. b. Factory prepared pipe boots should fit snugly but not require excessive force
        to pull over a pipe. If a pipe boot feels overly snug but workable, try applying
        either talc powder or using compressed air with a nozzle to float the boot
        sleeve over and along the pipe.
      3. c. Pipe boots should never be used if the force required to install them stresses
        or weakens the boot. When properly installed, the pipe boot will lay flat
        against grade surrounding pipe without leaving pockets that may become
        stressed during or after placement of backfill.
      4. d. Pipe boot aprons should be seamed to the parent geomembrane using one of
        the repair techniques described in the Seaming Section above (see 3.01C Field
        Seaming).
      5. e. Proper leak-proof sealing of pipe boots should be verified by non-destructive
        methods (see section 3.01 D). The pipe boot sleeve should be attached to the
        pipe using butyl tape between the pipe and boot and two stainless steel
        clamps.
      6. f. When cover materials are not used (see section 3.01.F below), splash pads or
        additional geomembrane layers shall be used for all inflow pipes to prevent
        long term wear and damage to the geomembrane caused by the direct impact
        of the inflow on the geomembrane panels. The pads should be welded on top
        of the geomembrane panels and tested according to sections 3.01.C and D,
        respectively. Common splash panel sizes are 1.2 to 1.8 m (4 to 6 ft) in all directions.
        However, larger sizes may be required depending on the amount of
        inflow pipes and the height to the discharge point.
    2. 2. Concrete
      1. a. Where bonding a geomembrane to concrete (or masonry) is required, the concrete
        surface should be smooth, clean, dry, and free of any sharp protrusions
        or rock in the backfill. Geomembrane to concrete seals shall be accomplished
        with mechanical anchors (e.g. fasteners, termination bars). An approved sealant
        is placed between the geomembrane and the concrete surface to ensure
        sealing.
      2. b. The geomembrane fixed to a concrete structure must be on firm soil subgrade
        that will not deform and stretch the geomembrane. Compacting of the soil
        subgrade around such structures must be performed with particular care so
        excessive differential movement between the concrete and soil subgrade does
        not occur.
    3. 3. Drains
      1. a. The geomembrane shall be mechanically fastened to the concrete structure at
        the location of water discharge. This detail requires the installation of a concrete
        base or structure at the location of the drain.
      2. b. Where water enters or exits the geomembrane area, e.g., ponds, reservoirs,
        and canals, this point must have proper geomembrane termination so as not
        to damage the geomembrane. The area of inflow must be anchored or attached
        to a structure as designed by the Project Engineer or Design Professional.
        The geomembrane is installed and then anchored to the concrete prior
        to the covering with soil.
    4. 4. Aerators
      1. a. Geomembrane design in lagoons with aerators should require ballast, e.g. precast
        concrete slab, on the geomembrane to prevent uplift and to provide a
        pad to support the aerator when the water level is lowered. Many examples
        exist of geomembrane damage due to an aerator settling on the geomembrane
        or where the geomembrane was lifted into the aerator. Other aerator damage
        is frequently evidenced as cuts in the geomembrane along a specific elevation
        on the side slope where the aerators have been pulled to shore for maintenance.
        Geomembrane sheets are easily damaged by the sharp edges of a 6 mm (0.25 inch) thick
        stainless steel plate of an aerator.

      F. Cover Materials

      1. 1. When placing cover material or initially filling the containment area, it is important
        to ballast the geomembrane into the perimeter anchor trench before covering
        or filling. The anchor trench or perimeter shelf area should be the last area
        covered to complete the cover process.
      2. 2. Under all operating conditions, protection of the geomembrane will be required.
        Care should be taken when covering the geomembrane to prevent any damage. At
        no time will construction equipment be allowed to operate or drive directly on
        the geomembranes.
      3. 3. Any damage to the geomembrane should be repaired prior to proceeding with cover
        material placement. Costs associated with repairs are the general contractor’s
        responsibility.
      4. 4. The cover material shall be placed as soon as practical, in conjunction with or upon
        completion of the geomembrane installation or as the installation progresses to
        minimize traffic on the geomembrane and damage.
      5. 5. Access roads for clean soil cover should be maintained to provide 0.45 m (18 inch)
        minimum and for heavier equipment on haul roads a minimum of 0.90 m (36 inch)
        preferable between the excavation equipment and geomembrane at all times.
        Cover soil requirements should be verified before placement with the Design Professional
        and geomembrane installer.
      6. 6. Additionally, a protection geotextile layer may be needed in rougher soil conditions
        between the geomembrane and the cover materials. The use of a protection
      7. layer should be verified with the Design Professional and geomembrane fabricator.

      8. 7. Cover material shall consist of 12 mm (0.5 inch) minus particles, clean rounded
        soils or gravels free of sharp edges, sticks, metal, rubbish, and debris or foreign
        materials. Site specific materials or sizes may be acceptable. It is recommended
        that the contractor receive prior written approval of acceptance of the cover materials
        from a geomembrane representative and/or Design Professional before
        covering the geomembrane.
      9. 8. Cover soils should be dumped and leveled over the geomembrane and not pushed
        from one end to the other to minimize rolling and wrinkling of the geomembrane
        beneath the soils. Cover soil should always be placed from the bottom to the top
        of slopes to avoid stressing the geomembrane and slope stability problems.
      10. 9. Equipment should be turned in long sweeping turns and not spun quickly to eliminate
        the chance of tires digging down to the geomembrane thru the cover soil and
        wrinkling or stretching the geomembrane.
        1. a. If geomembrane damage does occur during construction, cover placement,
          and/or filling, DO NOT COVER IT UP. Advise the foreman and CQA personnel so
          repair can be made and documented which will make doing the repair a lot
          easier than after cover soil placement or filling.

      G. Field Acceptance

      1. 1. The Geomembrane will be accepted by the Owner’s Representative when all of
        the following have been completed:
        1. a. The entire installation is finished or on agreed upon subsections of the installation
          are finished (3.01 A through 3.01F).
        2. b. All Installer’s QC documentation is complete and submitted to the Owner.
        3. c. Verification of the adequacy of all field seams and repairs and associated geomembrane
          testing is complete.

      H. Site Clean Up and Demobilization

      1. 1. On completion of installation, the geomembrane installer shall dispose of all
        waste and scrap material in a location provided and approved by the owner. The
        installer should also remove all equipment used in connection with the work
        herein, and shall leave the premises in a neat and acceptable manner. No scrap
        material shall be left on the completed surface of the geomembrane.
      2. 2. Excess material shall be cut from the anchor trench areas and all scrap, sand
        bags, and debris, shall be removed just prior to final backfill of anchor trench
        with select cover soil.

      Part 4 – Measurement and Payment

      4.01 Measurement and Payment

      As per project specifications