ISO 9624:2019

Overview

ISO 9624:2019 specifies the mating dimensions for thermoplastics flange adapters and corresponding loose backing flanges used in thermoplastic piping systems for the conveyance of fluids under pressure. It covers pipes with nominal outside diameters (DN/OD) from 16 mm to 2 500 mm and nominal pressures up to 25 bar (PN 25). The standard addresses common joint types used in plastic piping: butt fusion, socket fusion and adhesive (bonded) systems, and provides information on gaskets, marking and correct assembly practice.

Key topics and technical requirements

• Mating dimensions: Defines geometrical requirements for flange adapters and mating loose backing flanges to ensure interchangeability and correct fit.
• Scope of application: Applies to flange adapters for butt fusion, socket fusion and adhesive-bonded piping systems for pressure service up to PN 25.
• Size range: Covers DN (nominal outside diameters) from 16 mm up to 2 500 mm, enabling large-diameter thermoplastic connections.
• Materials: Loose backing flanges may be made of metal, thermoplastics, or metal/thermoplastic combinations.
• Compatibility: Uses flange outer diameters and bolt circle values consistent with EN 1092-1 and thread/bolt hole sizes referenced to ISO standards (e.g., ISO 261, ISO 273).
• Gaskets and assembly: Informative annexes provide guidance on gaskets (Annex A), recommended bolt torque application (Annex B), and recommended dimensions for PE100 flange adapters (Annex C).
• Marking: Minimum marking requirements for flange adapters and loose backing flanges to support traceability and correct installation.
• Limitations: Does not cover industrial applications - those are addressed by ISO 15493, ISO 15494 or ISO 10931.

Practical applications and users

ISO 9624:2019 is essential for:

• Pipe and fitting manufacturers producing flange adapters and backing flanges for water and pressure piping systems.
• System designers and engineers who specify thermoplastic piping connections for municipal water, drainage, and non-industrial fluid conveyance.
• Valve and equipment suppliers ensuring compatible flange connections between thermoplastic pipelines and metal equipment.
• Contractors and installers who assemble flanged joints and require guidance on gaskets, bolt torques and correct mating dimensions.
• Specification writers and procurement teams needing normative references for procurement and compliance.

Benefits include improved interchangeability, reliable pressure-tight connections, and reduced assembly errors in thermoplastic piping installations.

Related standards

• EN 1092-1 (steel flanges and joint geometry)
• ISO 4427-3 (PE fittings)
• ISO 7005-1, ISO 261, ISO 273 (threads/bolt sizes)
• ISO 15493, ISO 15494, ISO 10931 (industrial thermoplastic piping standards)

Keywords: ISO 9624:2019, thermoplastics piping systems, flange adapters, loose backing flanges, mating dimensions, DN 2500, PN 25, butt fusion, socket fusion, adhesive bonded, gaskets, bolt torque.