EN ISO 3501:2022

• Abstract:

  This document specifies a method for checking the ability of assembled uniaxial joints between fittings and plastic pressure pipes to withstand longitudinal tensile stresses. The test applies regardless of the design and material of the fitting used for jointing plastics pipe.; This test method is not applicable to fusion-welded joints.

• Status: Published
• Publication Date: 11-Jan-2022
• Withdrawal Date: 30-Jul-2022
• ICS: 23.040.60 - Flanges, couplings and joints
• Technical Committee: CEN/TC 155 - Plastics piping systems and ducting systems
• Drafting Committee: CEN/TC 155 - Plastics piping systems and ducting systems
• Current Stage: 6060 - Definitive text made available (DAV) - Publishing
• Start Date: 12-Jan-2022
• Completion Date: 12-Jan-2022
• Ref Project: SIST EN ISO 3501:2022 - Plastics piping systems - Mechanical joints between fittings and pressure pipes - Test method for resistance to pull-out under constant longitudinal force (ISO 3501:2021)

• Replaces: EN ISO 3501:2015 - Plastics piping systems - Mechanical joints between fittings and pressure pipes - Test method for resistance to pull-out under constant longitudinal force (ISO 3501:2015)
• Effective Date: 19-Jan-2022
• Refers: ISO 17456:2006 - Plastics piping systems — Multilayer pipes — Determination of long-term strength
• Effective Date: 25-Aug-2026
• Refers: ISO 3126:2005 - Plastics piping systems — Plastics components — Determination of dimensions
• Effective Date: 25-Aug-2026
• Refers: EN 13476-3:2007+A1:2009 - Plastics piping systems for non-pressure underground drainage and sewerage - Structured-wall piping systems of unplasticized poly(vinyl chloride) (PVC-U), polypropylene (PP) and polyethylene (PE) - Part 3: Specifications for pipes and fittings with smooth internal and profiled external surface and the system, Type B
• Effective Date: 28-Jan-2026
• Referred By: EN 12201-5:2024 - Plastics piping systems for water supply, and for drains and sewers under pressure - Polyethylene (PE) - Part 5: Fitness for purpose of the system
• Effective Date: 28-Jan-2026
• Referred By: EN 1254-8:2021 - Copper and copper alloys - Plumbing fittings - Part 8: Press fittings for use with plastics and multilayer pipes
• Effective Date: 28-Jan-2026
• Referred By: EN 1254-6:2021+A1:2025 - Copper and copper alloys - Plumbing fittings - Part 6: Push-fit fittings for use with metallic tubes, plastics and multilayer pipes
• Effective Date: 28-Jan-2026
• Referred By: EN ISO 15876-5:2003 - Plastics piping systems for hot and cold water installations - Polybutylene (PB) - Part 5: Fitness for purpose of the system (ISO 15876-5:2003)
• Effective Date: 28-Jan-2026
• Referred By: EN ISO 15494:2015 - Plastics piping systems for industrial applications - Polybutene (PB), polyethylene (PE), polyethylene of raised temperature resistance (PE-RT), crosslinked polyethylene (PE-X), polypropylene (PP) - Metric series for specifications for components and the system (ISO 15494:2015)
• Effective Date: 28-Jan-2026
• Referred By: EN 1254-8:2021+A1:2025 - Copper and copper alloys - Plumbing fittings - Part 8: Press fittings for use with plastics and multilayer pipes
• Effective Date: 28-Jan-2026
• Referred By: EN ISO 15875-5:2003 - Plastics piping systems for hot and cold water installations - Crosslinked polyethylene (PE-X) - Part 5: Fitness for purpose of the system (ISO 15875-5:2003)
• Effective Date: 28-Jan-2026
• Referred By: EN ISO 15494:2018 - Plastics piping systems for industrial applications - Polybutene (PB), polyethylene (PE), polyethylene of raised temperature resistance (PE-RT), crosslinked polyethylene (PE-X), polypropylene (PP) - Metric series for specifications for components and the system (ISO 15494:2015)
• Effective Date: 28-Jan-2026
• Referred By: EN 1254-3:1998 - Copper and copper alloys - Plumbing fittings - Part 3: Fittings with compression ends for use with plastics pipes
• Effective Date: 28-Jan-2026
• Referred By: EN 12201-5:2011 - Plastics piping systems for water supply, and for drainage and sewerage under pressure - Polyethylene (PE) - Part 5: Fitness for purpose of the system
• Effective Date: 28-Jan-2026
• Referred By: EN 1254-6:2012 - Copper and copper alloys - Plumbing fittings - Part 6: Fittings with push-fit ends
• Effective Date: 28-Jan-2026

Overview

EN ISO 3501:2022 (identical to ISO 3501:2021) defines a standardized laboratory method to assess the resistance of mechanical (uniaxial) joints between fittings and plastic pressure pipes to longitudinal pull-out under a constant tensile force. The procedure applies to mechanical joint designs and materials used to connect plastic pressure pipes and fittings, but it is not applicable to fusion‑welded joints. The test verifies whether an assembled joint can withstand specified longitudinal tensile stresses representative of service or design conditions.

Keywords: EN ISO 3501:2022, ISO 3501:2021, plastics piping systems, mechanical joints, pull-out resistance test, pressure pipes, longitudinal tensile force

Key topics and requirements

• Scope and exclusions: Applies to assembled mechanical joints between fittings and plastic pressure pipes; excludes fusion‑welded joints.
• Test principle: An assembled joint is subjected to a constant longitudinal tensile force calculated from pipe dimensions and the relevant permissible hoop/working stress.
• Test parameters: Pull-out force, test duration, test temperature, and pipe free length must be defined by the referring standard; Annex A provides default parameters if not specified.
• Apparatus: Tensile loading equipment able to maintain a constant force within ±2% along the pipe axis. Force may be applied directly or via lever, dead weights, or fluid cylinders. Test temperature must be held to ±2 °C.
• Test pieces and preparation: Joints are assembled using manufacturer instructions. Components should normally be tested after 24 h post‑production (24 h is mandatory in case of dispute).
• Procedure: Measure mean wall thickness (ISO 3126), secure specimen, apply the calculated force gradually over 30 s and hold for the specified duration, then inspect for loosening or partial/complete pull‑out.
• Reporting: Test report must reference ISO 3501:2021, list component identification (sizes, materials, manufacturer codes), nominal pressure class or S‑series, test period, temperature, calculated force, free length, observations of loosening/pull‑out, influencing factors and test date.
• Force calculation: Annex A gives formulas to calculate the applied force for solid‑wall and multilayer pipes (solid‑wall force is based on 1.5× maximum permissible working stress). Multilayer calculations reference ISO 17456 for long‑term strength/pressure values.

Applications and users

• Manufacturers of plastic pipes and fittings (design validation and quality control)
• Independent test laboratories performing type and routine testing
• Product certification bodies and conformity assessment schemes
• Specifiers and procurement teams requiring demonstrable mechanical‑joint performance
• R&D teams evaluating new joint designs or materials

Related standards

• ISO 3126 - Plastics piping systems: determination of component dimensions
• ISO 17456 - Multilayer pipes: determination of long‑term strength (referenced for multilayer force calculations)

EN ISO 3501:2022 is a practical, traceable test method to ensure mechanical joints in plastics piping systems meet required pull‑out resistance under defined tensile loads - an essential element for safety, product standards compliance and system reliability.