Overview
ISO 24131-4:2026 sets out the requirements and test methods for factory-applied ceramic epoxy linings on ductile iron pipes used for non-potable water and sewerage applications, with operating temperatures up to 50°C. Developed by the International Organization for Standardization (ISO), this standard is a key reference for manufacturers, engineers, and quality assurance professionals working with ductile iron pipelines as specified in ISO 2531, ISO 7186, and ISO 16631.
The standard addresses both technical performance and quality control for internal polymeric protection systems utilizing ceramic epoxy. Excluded from scope are pipes for potable water and applications exceeding the specified temperature limit.
Key Topics
- Lining Material: Ceramic epoxy lining, factory-applied, containing at least 20% by volume of ceramic quartz, with a two-component amine-cured epoxy base.
- Surface Preparation: Clean, moisture-free pipe surfaces, typically prepared by blasting or grinding to achieve a roughness (Ra) of 12.5 μm or more.
- Lining Properties:
- Uniform color and appearance, free from defects such as pinholes, blisters, and cracks.
- Minimum localized thickness of 900 μm and average thickness of 1000 μm.
- Adhesion and Non-Porosity:
- High adhesion strength (minimum 8.0 MPa).
- Non-porous performance proven by electrical puncture tests.
- Performance Criteria:
- Abrasion and chemical resistance for sewerage applications.
- Resistance to impact (direct and indirect).
- Resistance to deformation (ovalization) and hot water exposure.
- Quality Control: Regular routine and performance testing, covering surface, appearance, thickness, adhesion, cross-linkage, and porosity.
Applications
ISO 24131-4:2026 is relevant for various industrial and municipal water and sewer infrastructure projects where ductile iron pipes are exposed to aggressive contents or corrosive sewerage, excluding potable water transport. Specific applications include:
- Sewage Systems: Ensuring resistance to abrasion and corrosive chemicals found in wastewater.
- Industrial Water Conveyance: Where high durability and lining integrity are critical under chemical or thermal stress.
- Infrastructure Repair and Replacement: When integrating with existing plastic or metal pipeline systems as specified in ISO 16631.
- Quality Assurance in Pipe Manufacturing: For producers of ductile iron pipes, the standard serves as a guideline for in-factory linings, covering process and performance validation.
By complying with ISO 24131-4:2026, specifiers and manufacturers can enhance the longevity and reliability of ductile iron pipes in demanding environments, minimize maintenance, and reduce lifecycle costs.
Related Standards
Professionals working with ISO 24131-4:2026 will also benefit from familiarity with complementary standards, including:
- ISO 2531: Ductile iron pipes, fittings, and accessories for water applications.
- ISO 7186: Ductile iron products for sewerage (key for abrasion and chemical resistance requirements).
- ISO 16631: Compatibility and connection with plastic pipeline systems.
- ISO 4624: Pull-off test for adhesion (essential for testing lining adherence).
- ISO 8503-1: Surface roughness characteristics for paint and lining applications.
- ISO 9001: Quality management systems for manufacturing control.
Practical Value
Adopting ISO 24131-4:2026 ensures consistent, high-quality internal protection of ductile iron pipes through strict requirements and clear, reproducible test methods. The standard delivers critical benefits:
- Enhances pipe lifespan by reducing internal corrosion and degradation risks.
- Improves safety and reliability in wastewater and industrial water transport.
- Facilitates compliance in international markets by providing a recognized benchmark.
- Supports quality assurance and process control throughout manufacturing and installation.
ISO 24131-4:2026 is an indispensable standard for ensuring durable, efficient, and compliant ductile iron pipeline systems, especially in demanding non-potable and sewage service environments.