SIST EN ISO 899-2:2024 PDF

Overview

EN ISO 899-2:2024 (ISO 899-2:2024) specifies a standardized laboratory method to determine the flexural creep behaviour of plastics using a simple three-point loading (mid-span loaded, freely supported beam) test. The document defines specimen requirements, test atmosphere, loading and deflection measurement practices, result calculation and presentation. It is intended to generate reliable creep data for engineering design, quality control and research.

Key topics and technical requirements

• Test scope and applicability
  • Applies to rigid and semi-rigid non-reinforced, filled and fibre‑reinforced plastics (moulded or machined specimens).
  • May be unsuitable for some fibre‑reinforced materials due to fibre‑orientation effects and for certain rigid cellular plastics (see ISO 1209‑1 and ISO 1209‑2).
• Specimens and conditioning
  • Defines specimen shape and dimensions (aligned with ISO 178-derived definitions), preferred types, and pre‑treatment/conditioning in standard atmospheres (see ISO 291).
• Apparatus and measurement
  • Requires a three‑point loading fixture with defined support spacing and a deflection‑measurement system meeting updated accuracy requirements; extensometer calibration references include ISO 9513 and ISO 16012 for dimensional measurement.
• Procedure
  • Covers preloading, selection of stress levels, loading schedules, time and temperature/humidity control, and optional recovery measurements.
• Data and results
  • Prescribes calculations and presentation for flexural‑creep modulus, flexural‑creep compliance, flexural stress, flexural‑creep strain, time to rupture and creep‑strength limit.
  • Recommends graphical outputs such as creep curves, creep‑modulus/time curves, isochronous stress‑strain curves and three‑dimensional representations.
• Precision and reporting
  • Includes guidance on precision and the required content for a complete test report.

Practical applications

• Produces time‑dependent deformation data for:
  • Structural and mechanical design (long‑term load performance)
  • Material selection and specification for components under sustained bending
  • Quality control and batch verification of plastics and compounded materials
  • Research & development, ageing studies and comparative material testing

Who should use this standard

• Materials engineers, design engineers and R&D laboratories working with thermoplastics, thermosets and reinforced plastics
• Quality control technicians and testing labs performing mechanical property verification
• Standards committees and product certifiers requiring harmonized flexural creep data

Related standards

• ISO 178 (flexural properties)
• ISO 291 (standard atmospheres)
• ISO 472 (vocabulary)
• ISO 9513, ISO 16012 (measurement and calibration)
• ISO 1209‑1 / ISO 1209‑2 (rigid cellular plastics - applicability notes)

Keywords: EN ISO 899-2:2024, ISO 899-2:2024, flexural creep, three-point loading, plastics testing, creep behaviour, flexural‑creep modulus.