ISO 179-1:2023

Overview

ISO 179-1:2023 - Plastics - Determination of Charpy impact properties - Part 1: Non-instrumented impact test specifies a standardized Charpy pendulum method for measuring the impact strength of plastics under defined conditions. The standard covers both notched and unnotched specimens, multiple specimen geometries and notch types, and prescribes apparatus verification, specimen preparation, conditioning and result calculation. The method is intended for estimating material toughness or brittleness and for producing comparative impact-strength data (not for direct design calculations).

Key Topics and Requirements

• Scope and applicability: Rigid thermoplastics, thermosets, fibre‑reinforced composites (including long‑fibre/laminar materials), and thermotropic liquid‑crystal polymers. Notched specimens are restricted for some materials (e.g., long‑fibre composites).
• Test principle: A single pendulum strike bends a supported specimen at high, nominally constant, velocity; energy absorbed on fracture is recorded (Charpy impact energy).
• Specimen types and orientation: Defines edgewise (blow on narrow face), flatwise (blow on broad face), and directional considerations for laminated/anisotropic materials (normal/parallel).
• Specimen preparation and conditioning: Requires moulding, extrusion or machining per referenced material preparation standards and conditioning per ISO 291 to control moisture/temperature effects.
• Apparatus and verification: Test machines and verification procedures referenced to ISO 13802 (Charpy, Izod and tensile impact verification). Micrometers and gauges must measure specimen dimensions with an uncertainty ≤ 0.02 mm; special measuring tips for notched specimen contours are required (see ISO 16012).
• Results and reporting: Procedures for calculating Charpy impact strength for notched and unnotched specimens, statistical treatment, significant figures and detailed reporting requirements.
• Supplementary guidance: Annexes include precision data (Annex B), methods for surface effects (Annex A), and notch tip radius measurement (Annex C).

Practical Applications and Who Uses It

ISO 179-1:2023 is used to:

• Compare impact strength across materials or formulations in R&D.
• Verify material performance during quality control for plastics manufacturers and compounders.
• Characterize toughness of composites and reinforced plastics in product development.
• Support materials selection by engineers assessing brittleness vs. toughness under impact. Primary users: materials testing laboratories, QA/QC teams, polymer scientists, composite engineers, certification bodies and suppliers needing reproducible Charpy impact data.

Related Standards (if applicable)

• ISO 179 series (other parts for instrumented testing)
• ISO 13802 - Verification of pendulum impact‑testing machines
• ISO 291 - Conditioning of plastics
• ISO 294 / 293 / 295 / ISO 2818 - Specimen moulding and machining guidance
• ISO 16012 - Determination of specimen dimensions

Keywords: ISO 179-1:2023, Charpy impact test, plastics, impact strength, notched/unnotched specimens, pendulum impact testing, material toughness, standardized testing.