ISO 10146:2019

Crosslinked polyethylene (PE-X) and crosslinked medium density polyethylene (PE-MDX) - Effect of time and temperature on expected strength

This document specifies the minimum values for expected strength as a function of time and temperature in the form of reference lines, for use in calculations on crosslinked polyethylene (PE-X) pipes and crosslinked medium density polyethylene (PE-MDX) pipes. NOTE 1 This document is applicable for pipes with the minimum level of crosslinking after production in accordance with Clause 4. NOTE 2 The density range for medium density polyethylene is 926 kg/m3 to 940 kg/m3 in accordance with ISO 17855-1:2014[2].

Tubes en polyéthylène réticulé (PE-X et PE-MDX) — Influence du temps et de la température sur la résistance espérée

General Information

• Status: Published
• Publication Date: 25-Feb-2019
• ICS: 23.040.20 - Plastics pipes
• Technical Committee: ISO/TC 138/SC 5 - General properties of pipes, fittings and valves of plastic materials and their accessories -- Test methods and basic specifications
• Drafting Committee: ISO/TC 138/SC 5/WG 5 - Polyolefin pipes
• Current Stage: 9092 - International Standard to be revised
• Start Date: 24-Oct-2024
• Completion Date: 13-Dec-2025

Relations

• Revises: ISO 10146:1997 - Crosslinked polyethylene (PE-X) pipes - Effect of time and temperature on the expected strength
• Effective Date: 12-Mar-2016

Overview

ISO 10146:2019 defines how to determine the expected strength of pipes made from crosslinked polyethylene (PE‑X) and crosslinked medium density polyethylene (PE‑MDX) as a function of time and temperature. The standard supplies reference lines (mathematical equations, graphs and tables) giving minimum long‑term hydrostatic strength for use in design calculations and lifetime assessments of PE‑X and PE‑MDX piping systems. It applies to pipes meeting the minimum degree of crosslinking specified in Clause 4 and to PE‑MDX within the density range 926–940 kg/m3 (per ISO 17855‑1:2014).

Key topics and technical requirements

• Reference lines and formulae: The standard provides analytical reference lines for temperatures between 20 °C and 95 °C and separate expressions for 110 °C. These describe log(time) as a function of temperature (K) and hoop stress (MPa), enabling interpolation and controlled extrapolation.
• Degree of crosslinking: Minimum crosslinking after production is required and quantified by gel content (ISO 10147). Typical minimums: peroxide and UV processes ≥70%, silane ≥65%, electron beam ≥60%.
• Extrapolation and activation energy: Temperature dependence is based on an Arrhenius approach with an activation energy of 110 kJ/mol. The standard lists extrapolation factors (k) to convert life at 110 °C to lower temperatures (e.g., k ≈ 4 at ≤95 °C, k ≈ 18 at ≤80 °C, k ≈ 50 at ≤70 °C, k ≈ 100 for <50 °C).
• Tabulated and graphical data: Expected hoop strength values for various temperatures and exposure times are tabulated (no safety/design factors included) and plotted for PE‑X and PE‑MDX.
• Conformance testing: Annex A details demonstration methods (pressure testing per ISO 1167‑1/2, long‑term hydrostatic testing per ISO 9080). At least 97.5% of experimental results should lie on or above the reference line. Specific temperature/time test points and required failure‑time distributions are defined.

Applications and users

• Pipe manufacturers and material suppliers: validate production batches and verify degree of crosslinking.
• Design and pressure‑rating engineers: calculate allowable hoop stress and predict service life of PE‑X / PE‑MDX piping in heating, potable water, and industrial applications.
• Specifiers, testing labs and regulatory bodies: use reference lines for compliance, quality assurance and warranty assessments.
• R&D teams: compare new formulations or crosslinking processes against agreed long‑term performance baselines.

Related standards

• ISO 9080 - long‑term hydrostatic strength by extrapolation
• ISO 10147 - estimation of degree of crosslinking (gel content)
• ISO 1167‑1 / ISO 1167‑2 - resistance to internal pressure test methods
• ISO 17855‑1 - PE material designation and density ranges

Keywords: ISO 10146:2019, PE‑X, PE‑MDX, crosslinked polyethylene, expected strength, time and temperature, hoop strength, long‑term hydrostatic strength.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 10146
Second edition
2019-03
Crosslinked polyethylene (PE-X)
and crosslinked medium density
polyethylene (PE-MDX) — Effect of
time and temperature on expected
strength
Tubes en polyéthylène réticulé (PE-X et PE-MDX) — Influence du
temps et de la température sur la résistance espérée
Reference number
©
ISO 2019
© ISO 2019
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Published in Switzerland
ii © ISO 2019 – All rights reserved

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Characteristics . 2
5 Basic formulae . 2
6 Expected strength . 3
6.1 Extrapolation limits . 3
6.2 Graphical representation . 4
6.3 Tabulated values . 4
Annex A (normative) Demonstrating conformance of pipes to the reference lines .10
Bibliography .11
Foreword
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.org/iso/foreword .html.
This document was prepared by ISO/TC 138, Plastics pipes, fittings and valves for the transport of fluids,
SC 5, General properties of pipes, fittings and valves of plastic materials and their accessories — Test
methods and basic specifications.
This second edition cancels and replaces the first edition (ISO 10146:1997), which has been technically
revised. The main changes compared to the previous edition are as follows:
— a second type of material termed crosslinked medium density polyethylene (PE-MDX) has been
[1]
added in accordance with DIN 16894:2011 ;
— the minimum degree of crosslinking applicable for pipe conforming to this document is specified.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/members .html.
iv © ISO 2019 – All rights reserved

INTERNATIONAL STANDARD ISO 10146:2019(E)
Crosslinked polyethylene (PE-X) and crosslinked medium
density polyethylene (PE-MDX) — Effect of time and
temperature on expected strength
1 Scope
This document specifies the minimum values for expected strength as a function of time and
temperature in the form of reference lines, for use in calculations on crosslinked polyethylene (PE-X)
pipes and crosslinked medium density polyethylene (PE-MDX) pipes.
NOTE 1 This document is applicable for pipes with the minimum level of crosslinking after production in
accordance with Clause 4.
3 3
NOTE 2 The density range for medium density polyethylene is 926 kg/m to 940 kg/m in accordance with
[2]
ISO 17855-1:2014 .
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 references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 9080, Plastics piping and ducting systems — Determination of the long-term hydrostatic strength of
thermoplastics materials in pipe form by extrapolation
ISO 10147, Pipes and fittings made of crosslinked polyethylene (PE-X) — Estimation of the degree of
crosslinking by determination of the gel content
ISO 1167-1, Thermoplastics pipes, fittings and assemblies for the conveyance of fluids — Determination of
the resistance to internal pressure — Part 1: General method
ISO 1167-2, Thermoplastics pipes, fittings and assemblies for the conveyance of fluids — Determination of
the resistance to internal pressure — Part
...