IS 16352:2020
BIS Guidelines for HDPE Geomembranes: Technical Specifications per IS 16352:2020
The Bureau of Indian Standards (BIS) provides comprehensive guidelines for high-density polyethylene (HDPE) geomembranes through IS 16352:2020, titled “Geosynthetics – High Density Polyethylene (HDPE) Geomembranes for Lining – Specification.” This standard is a critical reference for civil engineers designing impermeable lining systems for applications such as landfills, canal linings, wastewater treatment facilities and waterproofing structures. By specifying requirements for production, quality and performance, IS 16352:2020 ensures HDPE geomembranes deliver long-term durability, chemical resistance and environmental protection. Below is a detailed exploration of the standard, covering material properties, manufacturing processes, installation guidelines, testing protocols and certification requirements.
Scope and Objectives of IS 16352:2020
IS 16352:2020 defines the specifications for both smooth and textured HDPE geomembranes used as impermeable barriers in civil engineering applications. The standard addresses:
Impermeability: Ensures minimal hydraulic conductivity (k ≤ 10⁻¹² cm/s) to prevent leakage of contaminants or water.
Durability: Guarantees resistance to chemical, biological and UV degradation, with a service life of 20–50 years in typical conditions.
Mechanical Performance: Provides sufficient tensile strength and puncture resistance to withstand installation stresses and operational loads.
Environmental Protection: Supports containment of hazardous materials (e.g., leachate in landfills) and water conservation (e.g., canal linings), reducing environmental impact.
The standard applies to geomembranes with thicknesses ranging from 0.75–3.0 mm, suitable for applications such as:
Landfill Liners: Preventing leachate migration, with geomembranes reducing contaminant flux by >99% in composite liner systems.
Canal Linings: Minimizing seepage losses by 80–95% in irrigation canals, enhancing water use efficiency.
Wastewater Treatment: Containing aggressive effluents (pH 2–12) in treatment ponds and lagoons.
Waterproofing: Protecting infrastructure (e.g., tunnels, basements) from groundwater ingress.
Material Characteristics of HDPE Geomembranes
HDPE geomembranes are manufactured from high-density polyethylene resins, offering superior strength, flexibility and chemical resistance. Key properties per IS 16352:2020 include:
Physical Properties:
Thickness: 0.75–3.0 mm (per IS 13162 Part 3), with tolerances of ±10% for smooth and ±15% for textured geomembranes.
Density: ≥ 0.94 g/cm³ (per IS 13360 Part 5), ensuring high molecular weight for durability.
Surface Texture (for textured geomembranes): Asperity height ≥ 0.25 mm, enhancing interface friction (coefficient ≥ 0.8) with soils or geotextiles.
Mechanical Properties:
Tensile Strength at Yield: ≥ 15–40 kN/m for 1.0–3.0 mm thickness (per IS 13326 Part 1), resisting installation and operational stresses.
Elongation at Break: ≥ 400% for smooth geomembranes, ≥ 100% for textured, accommodating deformation without failure.
Puncture Resistance: ≥ 300–800 N (per IS 13162 Part 4), protecting against sharp objects in subgrade or waste.
Tear Strength: ≥ 125–300 N (per IS 14293), ensuring resistance to tearing during handling.
Hydraulic Properties:
Hydraulic Conductivity: ≤ 10⁻¹² cm/s, ensuring impermeability under hydrostatic pressures up to 100 kPa.
Water Vapor Permeability: ≤ 0.2 g/m²/day (per IS 15909), minimizing moisture transmission in waterproofing applications.
Durability:
Chemical Resistance: Stable in aggressive environments (pH 2–12, including leachates with heavy metals or hydrocarbons).
UV Resistance: ≥ 70% strength retention after 1,600 hours of exposure (per IS 14324), critical for temporary exposure during installation.
Oxidative Induction Time (OIT): ≥ 100 minutes at 200°C (per IS 15909), indicating resistance to oxidative degradation.
Service Life: 20–50 years, based on accelerated aging tests in landfill and canal conditions.
Manufacturing and Quality Control
IS 16352:2020 mandates stringent manufacturing processes to ensure consistent quality:
Production:
Geomembranes are produced via extrusion or calendering, using virgin HDPE resins with ≤ 2% carbon black for UV stabilization.
Textured geomembranes are created using co-extrusion or embossing to achieve specified asperity heights.
Rolls are manufactured in widths of 5–8 m and lengths up to 200 m, minimizing field seams.
Quality Control:
Manufacturers must implement quality management systems per IS/ISO 9001, with documented procedures for resin selection, extrusion, and surface texturing.
In-process testing includes thickness, density, and tensile properties at a frequency of one test per 1,000 m².
Seam integrity (e.g., fusion or extrusion welds) is verified using destructive testing (shear strength ≥ 90% of parent material, per IS 15910).
Installation Guidelines
Proper installation is critical to achieving the design performance of HDPE geomembranes. IS 16352:2020 recommends:
Site Preparation:
Prepare a smooth, compacted subgrade (≥ 95% Proctor density, per IS 2720 Part 8) free of sharp objects, roots, or debris.
Ensure subgrade CBR ≥ 5% or place a protective geotextile (≥ 200 g/m²) to prevent punctures.
Slope surfaces to ≤ 1V:3H for landfill liners to maintain geomembrane stability.
Geomembrane Placement:
Unroll geomembranes with minimal wrinkles, aligning panels to minimize seams in high-stress areas.
Overlap panels by 100–150 mm for fusion welding or 300 mm for extrusion welding, ensuring continuous impermeability.
Deploy during low-wind conditions (< 20 km/h) to prevent uplift and misalignment.
Seaming:
Use double-track fusion welding or extrusion welding, achieving shear strength ≥ 90% and peel strength ≥ 70% of parent geomembrane (per IS 15910).
Test seams non-destructively (e.g., air pressure or vacuum testing) at 100% coverage and destructively (e.g., shear and peel tests) at one sample per 150 m of seam.
Anchoring:
Secure geomembranes in anchor trenches (depth ≥ 500 mm, width ≥ 1 m) filled with compacted backfill (≥ 90% Proctor density).
Use ballast (e.g., sandbags, soil cover) to prevent wind uplift during installation.
Cover Placement:
Place protective layers (e.g., geotextiles, soil cover ≥ 300 mm) immediately after seaming to prevent UV and mechanical damage.
Use low-ground-pressure equipment (contact pressure < 50 kPa) to avoid geomembrane stress.
Testing and Conformity
IS 16352:2020 requires rigorous testing to verify compliance:
Laboratory Testing (in BIS-approved labs):
Mechanical Tests: Tensile strength, puncture resistance, tear strength (per IS 13326, IS 13162, IS 14293).
Hydraulic Tests: Hydraulic conductivity, water vapor permeability (per IS 15909).
Durability Tests: OIT, UV resistance, chemical stability (per IS 14324, IS 15909).
Field Testing:
Conduct non-destructive seam tests (e.g., air pressure for fusion welds, spark testing for extrusion welds) to detect leaks.
Perform trial welds daily to confirm welding parameters (e.g., temperature 350–450°C, speed 1–2 m/min).
Sampling frequency: One destructive test per 150 m of seam, one roll test per 5,000 m².
Conformance:
Non-compliant geomembranes (e.g., thickness < 90% of specified value) must be rejected or repaired with patches (minimum 300 mm overlap).
Labeling and BIS Certification
Labeling Requirements:
Each roll must bear the BIS Standard Mark (ISI Mark), indicating compliance with IS 16352:2020.
Labels include manufacturer details, batch number, thickness, roll dimensions, and date of manufacture, affixed every 2 m along the roll edge.
BIS Quality Control Order (QCO):
Mandates that all HDPE geomembranes sold in India conform to IS 16352:2020 and carry the BIS Standard Mark.
Non-compliance results in penalties under the BIS Act, 2016.
Certification Process:
Manufacturers apply through the BIS portal, submitting resin specifications, production records, and quality control plans.
BIS conducts factory inspections to verify manufacturing consistency and compliance with IS/ISO 9001.
Samples are tested in BIS-recognized laboratories, with certification granted upon successful compliance.
Applications and Performance Benefits
HDPE geomembranes per IS 16352:2020 deliver significant benefits:
Landfill Liners: Achieve >99% containment efficiency, protecting groundwater from leachate contamination (e.g., COD > 10,000 mg/L).
Canal Linings: Reduce seepage losses by 80–95%, saving 10–20% of irrigation water in large canal systems.
Wastewater Treatment: Withstand aggressive effluents, extending lagoon life by 15–30 years.
Waterproofing: Prevent structural damage, reducing maintenance costs by 20–40% in tunnels and reservoirs.
Practical Implications for Civil Engineers
Adherence to IS 16352:2020 ensures HDPE geomembranes meet stringent performance criteria, delivering reliable, cost-effective lining solutions. Engineers should:
Conduct site-specific assessments (e.g., subgrade stability, chemical exposure) to select appropriate geomembrane thickness and texture.
Verify seam quality through rigorous field testing to prevent leakage, which can increase remediation costs by 50–100%.
Train installation crews on welding and handling techniques to avoid common errors, such as overheating seams or inadequate anchoring, which can reduce impermeability by 10–20%.
By leveraging IS 16352:2020, civil engineers can design lining systems that comply with BIS standards, ensuring environmental protection, regulatory compliance and client satisfaction through enhanced durability and performance.
Complementary BIS Standards
IS 15910:2010 – Geosynthetics – Guidelines for Seaming of Geomembranes:
Provides detailed procedures for fusion and extrusion welding, ensuring seam integrity.
IS 13360:1992 – Plastics – Methods of Testing:
Governs density and tensile testing, supporting IS 16352:2020 requirements.
IS 2720 (Various Parts):
Guides subgrade preparation and testing (e.g., Proctor density, CBR) for installation readiness.