Overview
ISO 21003-5:2008 - "Multilayer piping systems for hot and cold water installations inside buildings - Part 5: Fitness for purpose of the system" - defines the characteristics and test parameters that demonstrate the fitness for purpose of multilayer pipe systems used inside buildings for hot and cold water (domestic or heating). It applies to multilayer pipes, fittings and their joints (including joints with other plastics and non‑plastics) and is intended to be used together with the other parts of ISO 21003.
Key topics and technical requirements
- Scope: Systems for conveying water inside buildings under specified design pressures and temperatures appropriate to application classes. Not applicable beyond the design temperature/pressure limits in ISO 21003-1.
- Materials: Stress-bearing polymeric layers include PB, PE-RT, PE‑X, PP and PVC‑C; PE‑X must be fully crosslinked and meet relevant product standards.
- System focus: Evaluates both joints and complete piping assemblies; tests must use the parameters in clauses 5.2–5.7.
- Mandatory tests and referenced methods:
- Internal pressure test (ISO 1167) - hydrostatic test pressures derived from pipe long‑term strength and design pressure (examples include design pressures of 4, 6, 8 or 10 bar and long-term test durations such as 1 000 h in some classes).
- Bending test (EN 713) - assesses leaktightness under bending at specified radii and pressures.
- Pull‑out test (EN 712) - verifies mechanical retention of fittings under calculated pull forces.
- Thermal cycling test (EN 12293) - checks joint resistance to temperature variations.
- Pressure cycling test (EN 12295) - evaluates joint resistance to repeated pressure changes.
- Vacuum leaktightness test (EN 12294).
- Test parameter derivation: Uses long‑term strength data, Miner’s rule (ISO 13760) and other referenced standards (e.g., ISO 17456 for long‑term strength).
Practical applications and users
- Who uses it:
- Manufacturers of multilayer pipes and fittings (product design and type testing)
- Test laboratories and conformity assessment bodies (type approval and certification)
- Specifiers, plumbing and HVAC engineers (product selection and system specification)
- Building owners, installers and contractors (compliance and installation verification)
- Practical value:
- Ensures durability, leak tightness and mechanical integrity of joints and systems under expected service conditions
- Supports product harmonization and evidence for compliance with national regulations and procurement requirements
- Facilitates selection of systems suitable for domestic potable water and heating applications
Related standards
- ISO 21003-1, -2, -3 (General, Pipes, Fittings) - use in conjunction with Part 5
- ISO/TS 21003-7 (conformity guidance)
- Product-family parallels: ISO 15875-5 (PE‑X), ISO 15874-5 (PP), ISO 15876-5 (PB), ISO 15877-5 (PVC‑C)
- Test standards: ISO 1167, EN 712, EN 713, EN 12293, EN 12294, EN 12295
Keywords: ISO 21003-5:2008, multilayer piping systems, fitness for purpose, hot and cold water installations, joint testing, internal pressure test, bending test, pull-out test, thermal cycling.
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