Material Specifications

LLDPE Geomembrane Specifications

Q: What is the difference between LLDPE and HDPE geomembranes?

LLDPE has higher elongation (700-800% vs 700% at break), superior multiaxial stress resistance, better low-temperature flexibility, and greater conformability to uneven subgrades. HDPE has higher tensile strength at yield, better chemical resistance to hydrocarbons, and higher rigidity. LLDPE is preferred for sites with differential settlement, agricultural lagoons, and applications requiring flexibility. HDPE is preferred for chemical containment, landfills, and applications requiring maximum chemical resistance.

Q: Can LLDPE geomembranes be welded the same as HDPE?

Yes, LLDPE is welded using the same dual-track hot wedge and extrusion welding methods as HDPE. However, LLDPE requires slightly lower welding temperatures (typically 50-100 degrees F lower than HDPE) due to its lower melting point. Trial welds and destructive testing procedures are identical. LLDPE seams achieve comparable peel and shear strengths to HDPE when properly welded by IAGI-certified technicians.

Q: What thickness LLDPE is recommended for agricultural lagoons?

Agricultural lagoons typically use 40-60 mil LLDPE geomembrane. The 40 mil thickness is suitable for smaller ponds with prepared subgrades and low mechanical loading. The 60 mil thickness is recommended for larger lagoons, sites with potential settlement, rocky subgrades, or where regulatory requirements specify a minimum thickness. LLDPE's superior flexibility makes it an excellent choice for agricultural applications where subgrade conditions are variable.

Q: Is LLDPE suitable for landfill applications?

LLDPE can be used in landfill applications, particularly as a cap liner or in areas where settlement is expected. However, HDPE is more commonly specified for landfill primary liners due to its superior chemical resistance to leachate and higher tensile strength at yield. LLDPE is sometimes used in composite liner systems as a secondary component or in final cover systems where long-term differential settlement is anticipated. Check with your state regulatory agency for approved materials.

Q: What is the low-temperature performance of LLDPE?

LLDPE maintains flexibility and impact resistance at temperatures significantly below freezing, typically down to -40 degrees F (-40 degrees C) or lower without becoming brittle. This is a major advantage over HDPE, which becomes increasingly rigid and susceptible to stress cracking below 40 degrees F. LLDPE is the preferred material for installations in cold climates, frozen ground applications, and areas subject to thermal cycling.

Linear low-density polyethylene (LLDPE) geomembrane material properties, ASTM test methods, HDPE comparison data, and application guidelines. Conforming to GRI-GM17 industry specification.

Material Properties

Minimum average roll values (MARV) per GRI-GM17 for smooth LLDPE geomembrane.

Property	Unit	30 mil	40 mil	60 mil	80 mil	Test Method
Thickness	mil (mm)	30 (0.75)	40 (1.00)	60 (1.50)	80 (2.00)	ASTM D5199
Density	g/cm³	≥0.939	≥0.939	≥0.939	≥0.939	ASTM D792
Tensile Strength at Break	lb/in (kN/m)	60 (10.5)	80 (14.0)	120 (21.0)	160 (28.0)	ASTM D6693
Tensile Strength at Yield	lb/in (kN/m)	26 (4.6)	35 (6.1)	52 (9.1)	69 (12.1)	ASTM D6693
Elongation at Break	%	≥800	≥800	≥800	≥800	ASTM D6693
Elongation at Yield	%	≥12	≥12	≥12	≥12	ASTM D6693
Tear Resistance	lb (N)	20 (89)	27 (120)	40 (178)	53 (236)	ASTM D1004
Puncture Resistance	lb (N)	44 (196)	60 (267)	90 (400)	120 (534)	ASTM D4833
Multiaxial Elongation	%	≥30	≥30	≥30	≥30	ASTM D5617
Carbon Black Content	%	2.0–3.0	2.0–3.0	2.0–3.0	2.0–3.0	ASTM D4218
Carbon Black Dispersion	rating	≤1 or 2	≤1 or 2	≤1 or 2	≤1 or 2	ASTM D5596
Stress Crack Resistance (NCTL)	hours	≥300	≥300	≥300	≥300	ASTM D5397
Oxidative Induction Time (OIT)	minutes	≥100	≥100	≥100	≥100	ASTM D3895

Values shown are minimum average roll values (MARV) per GRI-GM17. Textured LLDPE values differ; contact EFI for textured geomembrane specifications.

LLDPE vs. HDPE Comparison

Key performance differences between LLDPE and HDPE geomembranes for material selection.

Property	LLDPE	HDPE	Advantage
Tensile Strength at Yield	Lower (26-69 lb/in)	Higher (39-130 lb/in)	HDPE
Elongation at Break	≥800%	≥700%	LLDPE
Multiaxial Elongation	≥30%	N/A (not tested)	LLDPE
Flexibility	Highly flexible	Semi-rigid	LLDPE
Low-Temperature Performance	Excellent (to -40°F)	Fair (brittle below 40°F)	LLDPE
Stress Crack Resistance	≥300 hrs (rarely fails)	≥500 hrs (critical test)	LLDPE
Chemical Resistance (hydrocarbons)	Good	Excellent	HDPE
Welding Speed	Slightly slower	Standard	HDPE
Subgrade Conformability	Excellent	Fair to Good	LLDPE
UV Resistance (with carbon black)	Good	Good	Equal

Referenced ASTM Test Methods

ASTM D6693

Tensile Properties of Geomembranes (Type IV specimen, 2 in/min)

ASTM D1004

Tear Resistance of Plastic Film and Sheeting (Die C)

ASTM D4833

Index Puncture Resistance of Geomembranes (CBR probe, 12 in/min)

ASTM D5397

Stress Crack Resistance by Notched Constant Tensile Load (NCTL) Test

ASTM D5617

Multiaxial Tension Test for Geosynthetics (burst test)

ASTM D792

Density and Specific Gravity of Plastics by Displacement

ASTM D4218

Carbon Black Content in Polyethylene by Muffle Furnace

ASTM D5596

Microscopic Evaluation of Carbon Black Dispersion in Polyolefin Geosynthetics

ASTM D3895

Oxidative Induction Time by DSC (Standard OIT)

GRI-GM17

Standard Specification for Test Properties, Testing Frequency, and Recommended Warranty for LLDPE Smooth and Textured Geomembranes

Applications

Agricultural Lagoons

Animal waste containment, dairy lagoons, swine waste systems, and agricultural process water ponds where subgrade settlement is expected.

Secondary Containment

Tank farm containment, chemical storage areas, fuel depots, and industrial facilities requiring flexible, conformable barriers.

Settling Areas

Sites with anticipated differential settlement, unstable subgrades, seismic zones, and areas prone to ground movement.

Cold Climate Installations

Northern latitude projects, high-altitude sites, and applications subject to freeze-thaw cycling where low-temperature flexibility is critical.

Frequently Asked Questions

What is the difference between LLDPE and HDPE geomembranes?

LLDPE has higher elongation (800%+ vs 700%+), superior multiaxial stress resistance, better low-temperature flexibility, and greater conformability to uneven subgrades. HDPE has higher tensile strength at yield, better chemical resistance to hydrocarbons, and higher rigidity. LLDPE is preferred for sites with differential settlement and agricultural lagoons. HDPE is preferred for chemical containment and landfills.

Can LLDPE geomembranes be welded the same as HDPE?

Yes, LLDPE uses the same dual-track hot wedge and extrusion welding methods. However, LLDPE requires slightly lower welding temperatures (typically 50-100°F lower) due to its lower melting point. Trial welds and destructive testing procedures are identical.

What thickness LLDPE is recommended for agricultural lagoons?

Agricultural lagoons typically use 40-60 mil LLDPE. 40 mil works for smaller ponds with prepared subgrades. 60 mil is recommended for larger lagoons, sites with potential settlement, or rocky subgrades. LLDPE's superior flexibility makes it ideal for agricultural applications.

Is LLDPE suitable for landfill applications?

LLDPE can be used in landfill cap liners and areas with expected settlement. However, HDPE is more commonly specified for primary liners due to superior chemical resistance. LLDPE is sometimes used in composite systems or final covers where differential settlement is anticipated.

What is the low-temperature performance of LLDPE?

LLDPE maintains flexibility and impact resistance down to -40°F (-40°C) without becoming brittle. This is a major advantage over HDPE, which becomes rigid below 40°F. LLDPE is the preferred material for cold climate installations and frozen ground applications.

Download LLDPE Specification Sheet

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