ISO 21138-2:2020

Overview

ISO 21138-2:2020 specifies definitions and requirements for structured‑wall piping systems of unplasticized poly(vinyl chloride) (PVC‑U), polypropylene (PP) and polyethylene (PE) intended for non‑pressure underground drainage and sewerage. Part 2 covers Type A products - pipes and fittings with smooth external and internal surfaces - and complements ISO 21138‑1. The standard sets out material, geometric, physical, mechanical and performance requirements, plus test methods and test parameters for a range of sizes, constructions and nominal ring stiffnesses. For dimensions larger than DN/OD 1200 (or DN/ID 1200) the document serves as general guidance.

Key Topics and Requirements

• Materials: Requirements for PVC‑U, PP and PE pipe and fitting materials, including provisions on the use of virgin and non‑virgin (reprocessed/recycled) materials (normative annexes).
• Type A definition: Pipes and fittings with smooth external and internal surfaces; covers multilayer/hollow‑wall constructions (Type A1, A2).
• Geometrical characteristics: Designation, lengths, diameters, wall thicknesses and joint dimensions for sockets and spigots.
• Joints and jointing methods: Applicability to elastomeric ring‑seal joints (integral sockets), welded and fused joints, and joints with other plastic/non‑plastic components.
• Physical and mechanical properties: Tests for ring stiffness, ring flexibility, tensile strength (including seam strength for some constructions) and other mechanical characteristics.
• Performance and marking: Performance requirements and minimum marking information for pipes and fittings.
• Test methods: Standardized test procedures and parameters referenced or included to verify conformity.
• Colour recommendations and appearance: Guidance on colours and appearance for system components.

Practical Applications

• Designed for non‑pressure underground drainage and sewerage systems in buildings, civil works and municipal networks.
• Suitable also for highway drainage and surface‑water applications.
• Use cases include main and branch drains, stormwater conveyance, culverts and similar gravity drainage systems where structured‑wall thermoplastic pipes are appropriate.

Who Should Use This Standard

• Manufacturers of PVC‑U, PP and PE structured‑wall pipes and fittings (to design, test and mark products).
• Specifiers, purchasers and engineers (for selecting appropriate materials, ring stiffness and joint types to meet installation codes and performance needs).
• Contractors and installers (to understand jointing methods, handling and installation compatibility).
• Regulatory bodies and testing laboratories (for conformity assessment and product testing).

Related Standards

• ISO 21138‑1 (general requirements for structured‑wall piping systems) - use in conjunction with ISO 21138‑2.
• ISO test methods cited in the normative references for specific material and performance tests.

Keywords: ISO 21138‑2:2020, structured‑wall piping systems, Type A, PVC‑U, PP, PE, non‑pressure underground drainage, sewerage, smooth external surface, ring stiffness, joints, test methods.