ISO 15874-3:2013

Overview

ISO 15874-3:2013 is the International Standard that specifies the requirements for polypropylene (PP) fittings used in plastics piping systems for hot and cold water installations. This Part 3 of the ISO 15874 series addresses the characteristics, materials, geometry, testing and marking of fittings intended for use within buildings - for domestic water distribution (whether or not for human consumption) and for heating systems - and complements ISO 15874-1 (general) and ISO 15874-2 (pipes).

Key updates in the 2013 second edition include the inclusion of PP‑RCT materials, adjustments to socket and electrofusion dimensions (electrofusion extended up to 160 mm), and revised mechanical characteristic values.

Key topics and technical requirements

• Scope and application classes: Defines use within buildings and links fitting performance to the application and design pressure classes in ISO 15874-1.
• Types of fittings covered:
  • Socket fusion fittings
  • Electrofusion fittings
  • Mechanical fittings (compression, crimped, flanged, flat‑seat unions)
  • Fittings with incorporated inserts
• Material characteristics:
  • Requirements for PP fitting materials (including when material is identical to the pipe compound or different)
  • Metallic insert and component material requirements
  • Consideration of potential effects on water intended for human consumption
• Geometrical characteristics: Socket and electrofusion socket dimensions, general dimensional tolerances (referencing ISO 3126)
• Mechanical and physical tests:
  • Hydrostatic resistance tests (referencing ISO 1167 series)
  • Long‑term hydrostatic strength (ISO 9080), melt flow (ISO 1133‑1), opacity (ISO 7686)
  • Sealing element material requirements (references EN 681‑1 / EN 681‑2)
• Performance, marking and documentation: Minimum marking, additional marking options and test/inspection parameters for conformity
• Normative references: Lists related test methods and material standards required for application of the standard.

Practical applications

ISO 15874-3:2013 is used to:

• Specify and certify PP fittings for building water distribution and heating systems.
• Define manufacturing tolerances, test methods and performance criteria for product development and quality control.
• Support procurement and compliance documentation for contractors and building owners.
• Guide laboratories in performing standardized tests for pressure, material and seal integrity.

Who should use this standard

• Plumbing and HVAC product manufacturers (fittings and joint systems)
• Design engineers and specification writers for buildings and heating systems
• Test laboratories and conformity assessment bodies
• Installers, contractors and regulators involved in plumbing codes or potable water systems

Related standards

• ISO 15874 series: Part 1 (General), Part 2 (Pipes), Part 5 (Fitness for purpose), Part 7 (Conformity guidance)
• Test and material standards: ISO 1167, ISO 9080, ISO 3126, ISO 1133‑1, ISO 7686
• Other system standards: ISO 15875 (PE‑X), ISO 15876 (PB), ISO 15877 (PVC‑C), ISO 22391 (PE‑RT)
• Relevant EN standards for seals and metallic materials: EN 681‑1/2, EN 1254‑3, EN 10088

Keywords: ISO 15874-3:2013, polypropylene fittings, plastics piping systems, hot and cold water installations, socket fusion, electrofusion, mechanical fittings, PP-RCT, hydrostatic testing.