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.

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Introduction

This test method is an alternative to other methods to determine long-term pressure performance of glass reinforced plastic pipes. The method removes the unpredictability of time to failure of specimens subject to constant pressure.

The main difference is that all specimens are aged at a constant internal pressure and temperature, and at a series of specified times individual specimens are loaded to short-term failure as a measure of their residual strength. When all the specimens have been tested, the residual strength is extrapolated over time to determine long-term performance.

This test method can be used to obtain data to establish internal pressure versus time-to-failure relationships. The procedures for establishing the relationships are not within the scope of this document. For such purposes, attention is drawn to ISO 10928 .

1 Scope

This document specifies a method for determining the long-term pressure endurance of glass-reinforced thermosetting plastics (GRP) pipes, based on the residual failure strength of test pieces after ageing for a specified time at specified internal pressure and temperature. The internal environment is specified in the referring standard. The external environment can be air or water.

2 Normative references

3 Terms and definitions

4 Principle

5 Apparatus

5.1 Measuring devices

5.2 End sealing devices

5.3 Supports

5.4 Container

5.5 Pressurising system

5.6 Pressure measuring device

5.7 Electric resistance meter

5.8 Strain measuring device(s)

6 Test pieces

6.1 Number

6.2 Free length

6.3 Cutting

7 Conditioning

8 Procedure

8.1 Temperature

8.2 Dimension measurements

8.3 Strain measurements

8.4 Sealing

8.5 Aging pressure

8.6 Failure pressure

9 Detection of failure

9.1 General

9.2 Detection methods

10 Test report

Bibliography