Overview
EN ISO 22088-2:2006 (ISO 22088-2:2006) - "Plastics - Determination of resistance to environmental stress cracking (ESC) - Part 2: Constant tensile load method" - specifies laboratory methods to assess environmental stress cracking (ESC) of thermoplastics under a constant tensile load in the presence of chemical agents. Adopted by CEN as EN ISO 22088-2:2006, the standard is intended as a comparative (ranking) test for specimens produced by moulding and/or machining and is not intended for direct design or performance prediction.
Key topics and technical requirements
- Test principle: specimens are held under a constant tensile load while immersed in (or coated with) a test medium; time and/or stress at rupture are recorded.
- Test methods:
- Method A - determine the tensile stress that causes rupture at 100 h (interpolation of time-to-rupture vs. stress).
- Method B - determine time-to-rupture under a single agreed stress (used when rupture time >100 h).
- Method C - determine times-to-rupture for a series of stresses (Method A is a subset of C).
- Apparatus & accuracy: tension device (weights or equivalent), inert contact materials, temperature-controlled bath/room (preferred 23 ± 2 °C or 55 ± 2 °C; up to 105 ± 2 °C possible), timer and force accuracy typically ±1 %.
- Specimen conditioning: default conditioning at (23 ± 2) °C and (50 ± 10) % RH for at least 24 h.
- Specimen prep & references: specimens prepared by moulding or machining per ISO 293, ISO 294-1, ISO 2818, ISO 3167, and test conditions aligned with ISO 527-2 where relevant.
- Stress limits: applied stress must be below the material’s yield stress (guideline: stress producing 2 % elongation after 1 h as maximum permissible; determine by preliminary tests).
- Test medium handling: complete immersion for liquids; for highly viscous agents a ≥2 mm coating may be used.
Applications and who uses it
- Material suppliers and compounders - comparative screening of formulations for ESC resistance.
- Plastics manufacturers - quality control and batch acceptance testing when products may contact specific chemicals.
- R&D and product development - rank candidate materials for chemical exposure environments.
- Failure analysis and forensic labs - reproduce ESC conditions to investigate cracking incidents.
- Regulatory and procurement teams - specification of ESC resistance in material data sheets (as comparative evidence).
Note: because EN ISO 22088-2:2006 is essentially a ranking test, users should avoid using results alone for structural design or long-term life prediction.
Related standards
Keywords: environmental stress cracking, ESC testing, constant tensile load, thermoplastics, ISO 22088-2:2006, EN ISO 22088-2, plastic material screening, test specimen conditioning.
