Geomembrane Sheets (HDPE / LLDPE) for Agriculture Industry
Table of Contents
Introduction to Geomembranes in Agriculture
Geomembranes are impermeable polymeric sheets used extensively in agricultural water management systems for:
Lining irrigation ponds
Lining reservoirs
Preventing seepage in canals
Protecting groundwater
Fertilizer and chemical storage
Silage covers
Agriculture requires geomembranes that withstand:
Constant water pressure
UV radiation
High temperature cycles
Aggressive fertilizers
Mechanical stress from soil and stones
Animal and equipment traffic
The primary geomembranes used in agriculture are HDPE, LLDPE, and VLDPE.
Types of Geomembranes
Polymer Structure & Gas-Grade Material Requirements
Gas-grade PE100 is not the same as water-grade PE100.
It must meet additional requirements:
Molecular Structure
Very high molecular weight HDPE
Narrow molecular weight distribution
High ESCR (Environmental Stress Crack Resistance)
Resistance to slow crack growth (SCG)
Carbon black 2–2.5% uniformly dispersed for UV protection
Critical Properties for Gas Pipelines
Property Requirement MRS (Minimum Required Strength) ≥10 MPa Carbon Black Dispersion Level ≤3 per ISO 11420 OIT (Oxidation Resistance) ≥20 min SCG (ASTM F1473 / ISO 13479) Excellent Toughness High impact resistance Gas pipelines rely on the regression curve generated using:
ISO 9080 (long-term pressure testing)
Minimum LPL (Lower Prediction Limit at 50 years)
Only materials with validated ISO 9080 curves can be used in gas projects.
Applications in Agriculture Industry
International Standards
ASTM D6693 – Tensile Test
Evaluates:
tensile strength
elongation at break
modulus
Agriculture relevance:
Ensures sheet stability under pond pressure
ASTM D4833 – Puncture Resistance
Critical for:
rocky soil
livestock foot pressure
agricultural machinery near ponds
GRI GM13 (HDPE) / GM17 (LLDPE)
Global benchmark specifications:
Includes:
thickness tolerance
density
OIT (oxidation induction time)
carbon black content
stress crack resistance (ASTM D5397 – NCTL)
melt flow index
ISO 9863 / ISO 9864 – Mass per Unit Area & Thickness
Ensures uniform thickness across sheet.
ISIRI 13329 (Iran National Standard)
Covers:
geomembrane testing
mechanical properties
thickness tolerance
UV exposure test
Material Composition & Polymer Engineering
Geomembranes are engineered from:
HDPE / LLDPE / VLDPE base resin
Carbon black (2–2.5%) for UV protection
Antioxidants
Heat stabilizers
Processing aids
Material Properties
Property HDPE LLDPE Tensile Strength Very High Medium Flexibility Low High Puncture Resistance High Medium Chemical Resistance Excellent Very Good UV Stability Excellent Good Agricultural use requires enhanced:
tear resistance
stress crack resistance
puncture resistance (rough soil)
Manufacturing Processes
Blown Film Extrusion
Used for LLDPE geomembranes
High flexibility
Flat Die Extrusion (Calendering)
Used for HDPE geomembrane sheets
Produces highly consistent thickness
Textured Geomembranes
Double or single-sided texture
Improves friction with soil (for steep ponds)
Installation Guidelines (Agriculture)
Site Preparation
Remove all stones/sharp objects
Use geotextile underlayer (300–600 g/m²)
Panel Deployment
Install at cooler times of day
Avoid overstretching
Anchor Trench
Depth: 40–60 cm
Width: 30–40 cm
Seaming
Performed by certified technicians.
Welding & Seaming Methods
Hot Wedge Welding
Most common for HDPE
Produces dual-tracked seams
Extrusion Welding
Used for:
corners
repairs
pipe penetration details
Air Pressure Testing of Seams
Required per ASTM D5820
Ensures watertight joining
Design Considerations
Include:
water depth (H)
slope angle
soil friction
hydrostatic pressure
wind uplift
UV exposure intensity
thermal expansion
HDPE is preferred for:
deep ponds
large reservoirs
LLDPE preferred for:
ponds with complex shapes
areas with cold temperatures
Durability & Environmental Resistance
UV Resistance
Carbon-black stabilizers allow:
20–25 years lifespan above water
Thermal Cycling Resistance
Handles:
+70°C surface temperatures
below-freezing night temperatures
Biological Resistance
Resists:
bacterial growth
algae
roots (with protective geotextile)
Failure Modes & QC
Common Failures
puncture from stones
seam failure
stress cracking (HDPE)
slope instability
QC Testing (On-site & Factory)
Vacuum seam test
Air channel test
Peel/Shear tests (ASTM D6392)
Spark testing (steel-backed)
FAQs
HDPE for large ponds; LLDPE for shaped/contoured ponds.
1.5–2.0 mm for agricultural reservoirs.
Yes—prevents puncture and extends lifespan.
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Polyethylene Fittings
Cast Iron and Steel Fittings
