Overview - EN ISO 21003-1:2008 (Multilayer piping systems)
EN ISO 21003-1:2008 (ISO 21003-1:2008) is the general (Part 1) system standard for multilayer piping systems used for hot and cold water installations inside buildings. It defines the scope, terminology, classification of service conditions and general requirements that apply to multilayer pipes, fittings and joints intended for domestic water supply and heating systems under specified design pressures and temperatures. EN ISO 21003-1 is a reference product standard and is intended to be used together with the other parts of ISO 21003.
Key topics and technical requirements
- Scope and application: Applies to multilayer piping systems with an inner plastic layer for conveying water - whether or not for human consumption - inside buildings. Covers a range of application classes and design pressures/temperatures (see the standard’s application class table).
- System approach: Defines that ISO 21003 is a system standard covering pipes, fittings and joints; Part 1 sets the general framework used by Parts 2 (pipes), 3 (fittings), 5 (fitness for purpose) and 7 (conformity guidance).
- Materials: Specifies acceptable stress-bearing polymeric materials including PB, PE‑RT, PE‑X, PP and PVC‑C. PE‑X must be fully crosslinked and comply with the relevant reference standards.
- Definitions and symbols: Provides standardized terms, geometry and service-condition definitions to ensure consistent specification and testing across products and markets.
- Influence on potable water: Notes potential effects of materials on water quality and instructs users to follow national regulations; the standard does not itself determine country‑by‑country potable water suitability.
- Scope exclusions and interfaces: Clarifies limits (e.g., solid-wall pipes with thin protective/barrier outer layers are treated separately in amendments to related ISO standards) and that ancillary equipment may be covered by other standards.
Practical applications and typical users
Who uses EN ISO 21003-1:
- Manufacturers of multilayer pipes, fittings and jointing systems for building services
- Product designers and R&D teams selecting polymer layers and adhesives
- Building services and plumbing engineers specifying systems for new-build and renovation
- Certification bodies and test laboratories performing conformity assessment
- Specifiers and procurement teams ensuring compliance with European and national rules
Typical uses:
- Specifying compliant multilayer plumbing systems for domestic hot/cold water and heating
- Establishing material selection criteria and system compatibility across components
- Guiding conformity assessment and product documentation when used with ISO 21003 Parts 2, 3, 5 and 7
Related standards
Keywords: EN ISO 21003-1:2008, ISO 21003, multilayer piping systems, hot and cold water installations, plumbing standards, pipes and fittings, water supply systems.