ISO 4152:2021 PDF

Overview

ISO 4152:2021 - Glass‑reinforced thermosetting plastics (GRP) pipes - Determination of the apparent axial long‑term modulus of pipes subject to beam bending - specifies a laboratory method to determine the apparent axial long‑term modulus of GRP pipes under beam bending. The test measures time‑dependent deflection of a water‑filled pipe supported between end‑couplers that allow rotation, and expresses results for use in mid‑span deflection and end‑rotation calculations (as used in ISO/TS 10986). The method is intended for practical pipe diameters up to DN 600.

Key topics and technical requirements

• Test principle: mount a pipe sample on end supports (end‑closures with rubber seals), fill with water, measure deflection at mid‑span and supports, and compute flexural deflection (centre minus average end deflection).
• Apparatus: stiff supporting frame, circular end closures, bracket supports glued at pipe springlines, and continuous displacement measuring devices with data acquisition.
• Measurement points and instrumentation:
  • Six displacement transducers mounted at springline brackets (two at mid‑span, four near ends).
  • Dimensional measuring devices for outside diameter, wall thickness and length (calibrated to ±1%).
  • Zero readings taken within 1 hour of mounting; filling time