ISO 12230:2012

Polybutene-1 (PB-1) pipes - Effect of time and temperature on the expected strength

ISO12230:2012 specifies minimum values for the expected strength as a function of time and temperature in the form of reference lines and tabulated data, for use in calculations on pipes made of polybutene-1 homopolymer (PB-H), and polybutene-1 random copolymer (PB-R). For the sake of simplicity the designation polybutene and the abbreviation PB are used throughout.

Tubes en polybutène-1 (PB-1) — Influence du temps et de la température sur la résistance espérée

General Information

• Status: Published
• Publication Date: 31-May-2012
• 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 - General properties of pipes, fittings and valves of plastic materials and their accessories -- Test methods and basic specifications
• Current Stage: 9093 - International Standard confirmed
• Start Date: 05-Dec-2022
• Completion Date: 13-Dec-2025

Relations

• Revises: ISO 12230:1996 - Polybutene (PB) pipes - Effect of time and temperature on the expected strength
• Effective Date: 21-Aug-2010

Overview

ISO 12230:2012 - "Polybutene-1 (PB-1) pipes - Effect of time and temperature on the expected strength" defines how to quantify the long‑term hoop strength of pipes made from polybutene-1. The standard provides reference lines, mathematical equations and tabulated hoop‑strength values as a function of time and temperature for polybutene homopolymer (PB‑H) and polybutene random copolymer (PB‑R). These reference data are intended for use in design calculations and conformity assessment of PB‑1 piping systems.

Key topics and technical requirements

• Scope: Minimum expected strength (hoop stress) vs. time and temperature for PB‑H and PB‑R pipes.
• Reference model: A four‑parameter mathematical model (two-branch equations) describes the reference lines; the lower value from the two branches defines the expected minimum hoop strength.
• Material designations: PB‑H = polybutene homopolymer; PB‑R = polybutene random copolymer (definitions and composition limits are given).
• Coefficients and temperature ranges: Distinct coefficient sets are provided for PB‑H (valid 10 °C to 110 °C) and PB‑R (valid 10 °C to 95 °C); graphical reference lines are shown in Figures 1 and 2.
• Tabulated values: Tables list calculated expected hoop strength values for various combinations of time and temperature for both PB‑H and PB‑R (Tables 2 and 3).
• Extrapolation: Arrhenius temperature dependence with an activation energy of 110 kJ/mol is used to derive extrapolation time factors (k) for specified temperature ranges; an extrapolation factor of 100 is acceptable up to 50 °C.
• Pre‑conditioning: Pipes shall be conditioned per manufacturer recommendations; PB‑R specimens require annealing 96 h at 95 °C before thermal stability testing at 110 °C.
• Conformance (Annex A): Test programs must produce failures across specified time intervals at key temperatures (20 °C, 60–82 °C, 95 °C). At least 97.5% of plotted experimental points must lie on or above the reference lines to demonstrate conformance; provisions are given for running data points and long tests.

Applications and users

Who uses ISO 12230:2012?

• Pipe manufacturers and compound formulators (PB‑H, PB‑R)
• Design and pipeline engineers performing lifetime and pressure‑rating calculations
• Testing laboratories and certification bodies assessing long‑term hydrostatic strength
• Standards committees and product specifiers for building/plumbing and industrial fluid systems

Practical uses:

• Determining allowable hoop stress for service life estimates
• Supporting product certification and compliance demonstrations
• Enabling extrapolation from accelerated tests to service temperatures

Related standards

• ISO 1167-1 / ISO 1167-2 - methods for determining resistance to internal pressure (referenced normative tests)
• ISO 9080 - procedures for long‑term hydrostatic strength extrapolation

Keywords: ISO 12230:2012, polybutene-1, PB-1 pipes, expected strength, hoop strength, time-temperature, PB-H, PB-R, long-term hydrostatic strength, reference lines, extrapolation.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 12230
Second edition
2012-06-01
Polybutene-1 (PB-1) pipes — Effect of time
and temperature on the expected strength
Tubes en polybutène-1 (PB-1) — Influence du temps et de la
température sur la résistance espérée
Reference number
©
ISO 2012
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
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Published in Switzerland
ii © ISO 2012 – All rights reserved

Contents Page
Foreword .iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Basic equations . 2
4.1 General . 2
4.2 Polybutene homopolymer (PB-H) . 2
4.3 Polybutene random copolymer (PB-R) . 2
5 Expected strength . 5
5.1 General . 5
5.2 Extrapolation limits . 5
5.3 Graphical representation . 5
5.4 Tabulated values . 5
Annex A (normative) Demonstrating conformance of pipes to the reference lines . 8
Bibliography . 9
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International
Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 12230 was prepared by Technical Committee ISO/TC 138, Plastics pipes, fittings and valves for the
transport of fluids, Subcommittee 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 12230:1996), which has been technically revised.
iv © ISO 2012 – All rights reserved

Introduction
The development of new polybutene-1 compounds based on random copolymers called PB-R means there is
a need to rename the existing PB-1 homopolymer compounds PB-H. At the same time a new set of reference
lines and tabulated expected hoop strength values for various times and temperatures needs to be included.
The main changes since the previous edition of this International Standard are
— new definition of PB-1 compounds PB-H (homopolymer) and PB-R (copolymers),
— new set of reference lines (coefficients and diagram),
— new table containing calculated expected hoop strength values,
— recalculation of hoop strength data of PB-H and specifying values rounded down to one decimal place,
— clearer specification of showing conformance to reference lines, and
— conformance to reference lines can be shown by not failed data points running at sufficiently high
hoop stress, too.
INTERNATIONAL STANDARD ISO 12230:2012(E)
Polybutene-1 (PB-1) pipes — Effect of time and temperature on
the expected strength
1 Scope
This International Standard specifies minimum values for the expected strength as a function of time and
temperature in the form of reference lines and tabulated data, for use in calculations on pipes made of
— polybutene-1 homopolymer (PB-H), and
— polybutene-1 random copolymer (PB-R).
For the sake of simplicity the designation polybutene and the abbreviation PB are used throughout.
2 Normative references
The following referenced documents are indispensable for the application 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 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 2: Preparation of pipe test pieces
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
reference line
minimum long-term hydrostatic strength to be expected from a particular polymer
NOTE 1 Reference lines are not to be considered as characteristic of a specific grade or of material from a specific supplier.
NOTE 2 The lines are described by a mathematical equation which permits interpolation and extrapolation in an
...