ISO 4152:2021

Glass‐reinforced thermosetting plastics (GRP) pipes - Determination of the apparent axial long‐term modulus of pipes subject to beam bending

This document specifies a method for determining the apparent axial long-term modulus of pipes subject to beam bending deflection between vertically supported end-couplers, which allow rotation of the pipe relative to the couplers. In conjunction with ISO 10928, this document expresses the results of the test as an apparent axial long-term modulus for use in the calculation of mid-span beam deflection and end rotation of GRP pipes as specified in ISO/TS 10986. Test conditions and requirements are specified in the referring standard. For practical reasons, the test method is not suited for diameters greater than DN 600.

Tubes en plastiques thermodurcissables renforcés de verre (PRV) — Détermination du module axial apparent à long terme de tubes soumis à la flexion de poutre

General Information

• Status: Published
• Publication Date: 18-May-2021
• ICS: 23.040.20 - Plastics pipes
• Technical Committee: ISO/TC 138/SC 6 - Reinforced plastics pipes and fittings for all applications
• Drafting Committee: ISO/TC 138/SC 6/WG 5 - Installation
• Current Stage: 6060 - International Standard published
• Start Date: 19-May-2021
• Due Date: 10-Jan-2022
• Completion Date: 19-May-2021

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 <1 hour.
• Conditioning and monitoring:
  • Test pieces and test water conditioned under test conditions for ≥24 h unless otherwise specified.
  • Deflection monitored continuously during filling and at least daily thereafter for 10 000 h.
• Calculations:
  • Initial modulus (Ei) computed from initial deflection using the pipe section second moment of area.
  • Long‑term (50‑year) modulus (E50) derived from an extrapolated 50‑year deflection using regression method A from ISO 10928:2016 (extrapolation based on 10 000 h test data).
• Reporting: includes references to ISO 4152, pipe identification, dimensions, test temperature, measurement intervals, initial and extrapolated deflections, computed moduli and any deviations or incidents.

Applications and users

ISO 4152:2021 is used to support structural design and serviceability assessments of GRP piping systems, especially for aboveground installations where beam bending between supports is critical. Typical users:

• GRP pipe manufacturers and quality laboratories validating long‑term flexural behaviour.
• Structural and piping engineers calculating mid‑span deflection and end rotation for supported runs.
• Specifiers, project engineers and certification bodies assessing long‑term performance and compliance.

Related standards

• ISO 10928:2016 - regression analysis and extrapolation methods used to compute long‑term modulus.
• ISO/TS 10986 - use of the modulus for mid‑span beam deflection and end rotation calculations.
• ISO 23856 (referenced in ISO 4152 introduction) - manufacturing requirements for GRP pipes.

Keywords: ISO 4152:2021, GRP pipes, glass‑reinforced thermosetting plastics, apparent axial long‑term modulus, beam bending, creep modulus, DN 600, ISO 10928, ISO/TS 10986.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 4152
First edition
2021-05
Glass‐reinforced thermosetting
plastics (GRP) pipes — Determination
of the apparent axial long‐term
modulus of pipes subject to beam
bending
Tubes en plastiques thermodurcissables renforcés de verre (PRV) —
Détermination du module axial apparent à long terme de tubes
soumis à la flexion de poutre
Reference number
©
ISO 2021
© ISO 2021
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Published in Switzerland
ii © ISO 2021 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Apparatus . 1
6 Test piece . 3
7 Number of test pieces . 3
8 Determination of the dimensions of the test piece . 3
8.1 Outside diameter, d . 3
o
8.2 Mean wall thickness, e . 3
8.3 Inner diameter, d . 4
i
8.4 Length . 4
9 Conditioning . 4
10 Procedure. 4
10.1 Preparation of test piece . 4
10.2 Preparation of supporting frame . 4
10.3 Mounting of test piece . 4
10.4 Mounting of displacement meters and zero readings . 5
10.5 Filling of test sample . 5
10.6 Monitoring deflection. 5
11 Calculating creep modulus . 5
12 Test report . 6
Bibliography . 7
Foreword
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This document was prepared by Technical Committee ISO/TC 138, Plastics pipes, fittings and valves for
the transport of fluids, Subcommittee SC 6, Reinforced plastics pipes and fittings for all applications.
Any feedback or questions on this document should be directed to the user’s national standards body. A
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iv © ISO 2021 – All rights reserved

Introduction
The apparent axial long-term modulus of pipes subject to beam bending of pipes manufactured
according to ISO 23856 is required for designing pipe systems installed aboveground in accordance
with ISO/TS 10986.
The modulus is used to calculate deflections and rotations of pipes installed on two or more supports.
INTERNATIONAL STANDARD ISO 4152:2021(E)
Glass‐reinforced thermosetting plastics (GRP) pipes —
Determination of the apparent axial long‐term modulus of
pipes subject to beam bending
1 Scope
This document specifies a method for determining the apparent axial long-term modulus of pipes
subject to beam bending deflection between vertically supported end-couplers, which allow rotation of
the pipe relative to the couplers.
In conjunction with ISO 10928, this document expresses the results of the test as an apparent axial
long-term modulus for use in the calculation of mid-span beam deflection and end rotation of GRP pipes
as specified in ISO/TS 10986.
Test conditions and requirements are specified in the referring standard.
For practical reasons, the test method is not suited for diameters greater than DN 600.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated reference
...