ISO 22391-2:2009

Overview

ISO 22391-2:2009 defines requirements for PE-RT (polyethylene of raised temperature resistance) pipes used in hot and cold water installations inside buildings. It covers both PE-RT Type I and Type II pipes and applies to systems conveying potable and non‑potable water, including heating systems. The standard specifies material evaluation, mechanical and geometrical characteristics, test parameters and methods, and marking - and is intended to be used together with other parts of ISO 22391 (Part 1: General, Part 3: Fittings, Part 5: Fitness for purpose of the system).

Keywords: ISO 22391-2, PE-RT pipes, hot and cold water installations, polyethylene raised temperature resistance, pipe standard

Key topics and requirements

• Material and performance: Pipes must be made from PE-RT; material evaluation is performed using long‑term hydrostatic strength methods (ISO 9080) and internal pressure tests per ISO 1167‑1/‑2 to determine allowable stress (σ) values.
• Type-specific strength curves: Reference strength (σ vs time) curves are given for Type I (typical range to 95 °C; additional 110 °C values) and Type II (up to 110 °C). Conformance requires most test results to lie on or above these reference lines.
• Test temperatures and durations: Typical test temperatures include 20 °C, 60–70 °C, and 95 °C; failure-time intervals cover short to very long durations (up to and beyond 8 760 h) to assess long‑term hydrostatic strength.
• Geometry and dimensioning: Specifies outside diameters, wall thickness tolerances and the maximum calculated pipe value (Scalc,max) per application class and design pressure; barrier layers may be present but are excluded from design diameter calculations.
• Physical characteristics: Surface appearance, opacity (ISO 7686), and cleanliness requirements; ends must be cut square.
• System scope: Applicable to pipes with or without barrier layers and to fittings/joints containing PE‑RT components.
• Marking and documentation: Minimum marking and identification requirements are set for traceability and correct application.

Practical applications

• Domestic hot and cold water distribution systems
• Building heating circuits and hydronic systems
• Internal plumbing where long‑term hydrostatic strength, temperature resistance and material certification are required

Who uses it: pipe manufacturers, product designers, plumbing and mechanical engineers, testing laboratories, specifiers, installers, building inspectors and regulatory bodies.

Related standards

• ISO 22391-1 (General)
• ISO 22391-3 (Fittings)
• ISO 22391-5 (Fitness for purpose)
• Test and measurement standards referenced: ISO 9080, ISO 1167‑1/‑2, ISO 3126, ISO 7686, ISO 1133‑1, ISO 2505, ISO 13760

Using ISO 22391-2 helps ensure PE‑RT piping systems meet recognized safety, durability and dimensional standards for building water and heating installations.