Technical Information Geomembrane

Lining for Containment

Physical Properties, Installation Guides

Flexible Polyethylene (FPE)

Permaflex Flexible Polyethylene (FPE) is a new generation multi layer geomembrane. It is manufactured with high resistance to base chemicals and chlorine. With slightly less flexibility than flexible polypropylene it still maintains the ability to flex where needed unlike HDPE which is stiff by nature.

Permaflex FPE is recommended for use to line tanks, including timber tanks, concrete and metal tanks. It is suitable for fish farms, liquid storage and as secondary lining. Permaflex FPE is also widely used for artificial lakes and irrigation canals.


Permaflex is a black flexible polyethylene geomembrane available in .3mm, .5mm, .75mm and 1mm thickness. It is the preferred alternative to PVC and polypropylene for tank liners as is not easily affected by chlorine. It is highly flexible and easily forms around corners. Suitable for ponds, reservoirs and liquid storage. Excellent UV resistance.


Permaflex FPE is manufactured in 4 grades, 0.3mm, 0.5mm, 0.75mm and 1mm thickness. Roll size is 6m x 100m or 8m x 100m. Permathene can supply the material to fabricators in roll form or we can manufacture to specific sizes in our Auckland factory. We are able to manufacture single panels which are folded or rolled ready to be deployed on site.

Permaliner has excellent UV resistance and retains flexibility even under extreme fully exposed weathering conditions. A 2.5% concentration of finest quality carbon with 97.15% polymer provides maximum protection against photochemical attack.

  • Containment. Primary and secondary containment lining for a variety of applications including tank, pond and canal for potable water, fish breeding in fresh or salt water, horticultural, decorative ponds, lining of earth dams, sediment ponds. Also suitable for lining effluent ponds for dairy and pigs (also floating covers for odour control) and waste containment.
  • Lining. Suitable as methane gas barrier where specified as a one-piece membrane, with all panels welded and placed under concrete, or alternatively taped.


Permaflex FPE (all grades) has been certified to meet AS/NZS 4020:2005 for use in contact with drinking water.

  • Taste of Water Extract: Passed
  • Appearance of Water Extract: Passed
  • Growth of Aquatic Micro-organisms: Passed
  • Cytotoxic Activity of Water Extract: Passed
  • Mutagenic Activity of Water Extract: Passed
  • Extraction of Metals: Passed

Note: Testing at 20 degrees Celcius (+/- 2 degrees), at an exposure of 15000 mm2 per litre.

UV Resistance

Permaflex FPE has excellent UV resistance and retains flexibility even under extreme fully exposed weathering conditions. A 2.5% concentration of finest quality carbon with 97.15% polymer provides maximum protection against photochemical attack.

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Permaflex FPE

High Density Polyethylene (HDPE)

HDPE is produced on state-of-the-art 3 layer extruders to 7.0 m and 8.0 m wide rolls to ISO 9001. The product is available in smooth ranging in thickness from 0.5 mm to 2.5 mm, and textured ranging in thickness from 1 mm to 2.5 mm. The material is manufactured to strict specifications with all testing in accordance with ASTM and GSI standards.


    • Mining. An HDPE geomembrane can prevent contamination of water and soil by providing a highly resistant barrier to chemicals produced during the extraction of precious metals.
    • Landfills. Highly resistant to hazardous chemicals HDPE has long been the lining of choice for this application. Used as either primary or secondary containment/ caps with or without GCL.
    • Irrigation Canals. To prevent water loss from seepage of water for man-made canals.
    • Tank Liners. Steel and concrete tanks are easily lined to prevent seepage loss. Also used as secondary lining under tanks in the petrochemical industries.


      • Hot Wedge Welding

The primary method for sealing HDPE is on-site by fusion using a portable hot wedge welder. The wedge melts the overlapped surfaces between pressure rollers. This produces a permanent homogeneous seam with an air channel which allows for pressure testing. During testing a successful weld is stronger than the material (the sample material will break before the weld peels apart).

        • Extrusion Welding

This is used for repairs and detail work such as pipe boots and protrusions. We use copper wire in our extrusion welds to reduce the possibility of defects for spark testing.


Although studies have proven that geomembrane failure is caused primarily during the covering stage from earth moving equipment, trucks, etc, an unacceptably high number (almost 20%) of failure is caused by poor workmanship during the welding stage.

We can provide geotechnical engineers to assist designers during any stage and to ensure all QA/QC is completed in accordance with specification as well as to monitor our own ISO 9001, 14001 Standards.

Permathene installation crews pay particular attention to detail and follow proven methods to ensure long-term success of the geomembrane liner. Foremost in any successful geomembrane installation is good design. Success of any lining system is dependent upon this.

Manufactured and tested to conform with GRI GM13.

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HDPE Landfill Liner

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HDPE Liquid Storage