» GEOMEMBRANES & POND LINERS
HiTeC manufactures high quality 3-layer co-extruded HDPE, LDPE, LLDPE & EVA geomembranes at large widths and at a thickness of 0,3-2,5 mm.
The geomembranes are made from virgin polymers specially selected for their strength and other useful characteristics. They are formulated with fine carbon-black to ensure the maximum lifetime and with antioxidants for protection against thermal degradation.
Geomembranes are used in a variety of applications, such as:
- Water reservoirs
- Landfills lining and capping
- Irrigation canals
- Mining
- Highways, dams, lake banks
- Aquaculture
- Pond lining
- Lining of metal tanks
HDPE geomembranes are made according to GRI- GM13 international standard at a width of 7 m and at a thickness range of 0,75-2,5 mm. They have the highest strength and chemical resistance.
LDPE, LLDPE & EVA liners are made at 0,3-1 mm at widths of 4-14 m (seamless), depending on the thickness. They are more flexible than HDPE, can be made in large widths and are easier to handle.
HiTeC's geomembranes are welded using hot air or hot wedge equipment by specialized installers.
Applications
Flexible membranes are used in a variety of applications, such as:
- Landfill lining
to protect the ground water from contamination. - Landfills capping
to prevent fluid flow in the landfill, to trap and properly vent the gases generated during decomposition of organic waste and to permit efficient revegetation and restoration of the area. - Water reservoirs
for collecting rain-water before it reaches the sea. - Reservoirs for waste-water
to protect the groundwater sources or streams. - Pond-lining
for artificial lakes and irrigation of farms. - Irrigation canals
an economic alternative to concrete and compacted earth for transporting water and irrigating large areas. Also used to reduce seepage from existing deteriorated concrete linings. - Protection of lake banks
for soil stabilization. - Tunnels
protecting the structure against humidity and water pressure. - Earth dams
for soil stabilization. - Underground insulation
of chemical plants, petrol stations & roads to prevent chemicals, oil etc. from polluting the underground water in case of a leakage. - Mining
for preventing contamination of the soil and underground water and permitting extraction of precious metals by heap leaching, using chemical solutions. - Tanks
secondary lining for preventing pollution in case of leakage or chemical spill. - Insulation of buildings & construction projects
- Evaporation basins
- Aquaculture
Water reservoirs for fish breeding.
Product Range
HiTeC' range of geomembranes includes HDPE, LDPE, LLDPE, EVA & FPP flexible membrane liners, in widths of up to 13 m at 0,3 mm thickness, 10 m at 0,5 mm thickness and 6 m at up to 2 mm thickness.
HiTeC's geomembranes contain 2,5% carbon-black with small particle size (< 25 nm) finely dispersed in the polymer mass to ensure the highest possible UV-resistance as well as a package of antioxidants for better thermal stability during manufacture, welding and end use.
Ingredients used (unless otherwise specified for certain types) are suitable for storage of potable water.
The membranes comply with international standards and specifications, such as GRI GM 13, and have been tested and approved by recognized laboratories. Rigorous quality control of every lot is carried at the company's fully equipped laboratory.
GEOMEMBRANE SELECTION
HiTeC manufactures the following types of geomembranes :
- HDPE
This material offers the highest tensile strength, impact strength, rigidity, tear & puncture resistance. It has very good ESCR (Environmental Stress Cracking Resistance) and the highest chemical resistance among polyolefin geomembranes. HDPE is the preferred choice in landfills lining, insulation of chemical plants, roads, petrol stations etc. as well as in mining, due to its chemical resistance. It is supplied in flat rolls 5,8 or 6 m wide at thickness of 0,75-2 mm. - LDPE/LLDPE
These materials have good mechanical properties and are more flexible than HDPE so they can be handled and laid easier. They can be produced at large widths (up to 13 m at 0,3 mm) that makes installation faster and more economic. They constitute good alternatives to HDPE where a very high chemical resistance is not essential, especially for pond-lining, irrigation canals and aquaculture ponds. An LDPE geomembrane made of recycled material is also available for short-term uses. - EVA
This material has the highest flexibility of all polyolefin liners and is often preferred as replacement of PVC membranes in pond-lining and metallic tank lining. Its softening point is lower to that of LDPE so it is not recommended to use it uncovered in warm climates. HiTeC produces various types of co-extruded EVA membranes, with Vinyl Acetate level between 9 % and 18 % (the higher the VA level the more elastic the membrane but the lower the softening point). - FPP
Flexible polypropylene is a new polymer with an exceptional combination of characteristics : very good mechanical properties, excellent ESCR, flexibility superior to polyethylene, excellent weldability and reparability, lighter weight per sq.m. and low coefficient of linear thermal expansion. These advantages make it an optimum choice for many applications requiring strength combined with flexibility and ease of installation.
Selection of geomembrane type for a specific project depends on the particular requirements of it. HiTeC' experts are at our customers' disposal to advise on the most appropriate type and thickness of liner for a given application.
HANDLING & INSTALLATION
Preparation of the site and the sub-grade
Successful lining equally depends on the quality of the membrane and on the selection, design and preparation of the site by the owner and the contractor.
The sub-soil should be sufficiently compacted, free of stones or other sharp objects and dry. The thickness of the membrane should be selected based on the angle of the slopes and other design parameters of the project.
Protection layers made of suitable minerals or geotextiles are often necessary.
Handling & laying of the membrane
Attention is necessary when unloading, transporting, storing and unrolling the membrane rolls in order to avoid damaging them.
The sheets should be fixed in anchor trenches at the crown of the embankment and then unrolled down never across the embankment. Individual sections are positioned with an overlap of 10-20 cm.
Detailed information on installation of geomembranes can be found at our "Installation Manual".WELDING
Welding of polyolefin geomembranes is effected with hot-air or hot-wedge equipment, by specialized personnel. Joints and repairs are made with extrusion welding equipment.
No welding should be performed during periods of high humidity, strong winds, long lasting intensive sunshine or temperatures below +5° C.
Before welding starts, it is necessary to carry preliminary tests in order to define the most suitable parameters (temperature, speed, pressure) for the specific climatic conditions and material type. Also, it is necessary to ensure that the sheets are completely clean, dry and free from imperfections. It is recommended that a test-channel is allowed to permit non- destructive testing by air pressure. Weld seams across slopes should be minimized, while cross-joints should be avoided and T-joints should undergo special testing to ensure their impermeability.