Overview
EN ISO 13268:2023 / ISO 13268:2022 specifies a laboratory test method to determine the initial (short‑term tangential ring stiffness) of thermoplastic shafts or risers used in inspection chambers and manholes for non‑pressure underground drainage and sewerage. Adopted by CEN as EN ISO 13268:2023, this standard updates and replaces earlier EN/ISO documents and clarifies how to test both regular (circular) and irregular (including square/rectangular or reinforced) shaft cross‑sections.
Key topics and technical requirements
- Scope: Measurement of short‑term tangential ring stiffness for thermoplastic riser shafts used in gravity drainage and sewer systems.
- Test principles:
- For regular cross‑section shafts (circular, plain or structured wall): follow the ISO 9969 ring stiffness test method - shaft supported horizontally and compressed vertically between two parallel plates at a constant speed; ring stiffness is calculated from force vs deflection, using the force to produce a deflection of 0.03 d (3% of diameter).
- For irregular, square or rectangular cross‑sections: modified procedure (this document) - apply compressive force with a bearer shaped to the external surface; deflection is measured in the range 2% to 6%; tests may be run at constant rate or constant load.
- Apparatus and test pieces: Specifies loading frames, plates/beams or V‑supports, and shaped bearers for irregular sections; references ISO 9969 apparatus for regular shafts.
- Calculation and reporting: Ring stiffness is calculated as a function of applied force and recorded deflection. Test report content and calculation methods are defined in the standard.
- Normative references: Includes ISO 9969 (ring stiffness of thermoplastic pipes) and ISO 48‑2 (rubber hardness), among others.
Practical applications and users
- Manufacturers of thermoplastic inspection chamber components and riser shafts use this standard to verify product stiffness and compliance for underground drainage applications.
- Testing laboratories apply the method to produce reproducible ring stiffness data for product certification and quality control.
- Designers, specifiers and contractors rely on ring stiffness results to select appropriate riser components for structural performance, load resistance and installation conditions in sewer and drainage systems.
- Regulatory bodies and certifiers reference the standard when defining performance criteria for non‑pressure underground drainage products.
Related standards
- ISO 9969 - Thermoplastics pipes: Determination of ring stiffness
- ISO 48‑2 - Rubber hardness determination (referenced)
- EN 14982:2006+A1:2010 - Superseded by EN ISO 13268:2023
Keywords: ring stiffness, thermoplastics shafts, inspection chambers, manholes, non‑pressure underground drainage, EN ISO 13268:2023, ISO 13268:2022, ring stiffness test, thermoplastic piping systems.
