EN ISO 2505:2023 PDF

Overview

EN ISO 2505:2023 - Thermoplastics pipes: Longitudinal reversion - Test method and parameters specifies a standardized laboratory method to measure longitudinal reversion (length change after heating) of thermoplastic pipes. Adopted by CEN as EN ISO 2505:2023, this fourth edition updates the 2005 version and extends material coverage (e.g., PE 100‑RC, PB‑H, PB‑R, PE‑RT, PP‑RCT, PE‑UHMW). The method applies to smooth‑walled thermoplastics pipes of constant cross‑section with wall thickness ≤ 16 mm (not for structured‑wall pipes). In case of dispute, a heated liquid bath is the reference medium.

Key topics and technical requirements

• Test principle: Measure a marked length on pipe specimens before and after exposure to a controlled heated environment (liquid bath or air oven); express reversion as percentage change in length.
• Specimen preparation:
  • Typical specimen length: 200 ± 20 mm (document also indicates a minimum length of 180 mm in table notes).
  • Mark two circumferential marks ~100 mm apart (or equivalent axial marks); prepare three specimens per sample.
  • Pipes taken from coils must be straightened prior to marking.
  • For large diameters (≥ 250 mm), cut test pieces into segments and test all segments.
• Apparatus:
  • Thermostatically controlled heated liquid bath or air oven capable of maintaining specified temperatures (thermometer accuracy ±0.5 °C).
  • Holding device for specimens, scriber, caliper with uncertainty ±0.1 mm.
  • Recommended liquids: glycerine, glycol, mineral oil (aromatic‑free), or calcium chloride solution - stable at test temperature and chemically inert to the polymer.
• Parameters (Table 1):
  • Material‑dependent temperatures and exposure times (examples from the standard):
    • PVC variants, SAN+PVC, PA (air oven): 150 ± 2 °C
    • PE grades (PE 32/40, PE 50/63, PE 80/100, PE‑RT, PE‑X): 100–120 °C
    • PP grades: 135–150 °C
    • ABS: 110 ± 2 °C
  • Exposure durations vary with wall thickness:
    • Liquid bath: 15 min (e ≤ 8 mm), 30 min (8