BS ISO 10928:2024
Plastics piping systems. Glass-reinforced thermosetting plastics (GRP) pipes and fittings. Methods for regression analysis and their use

Standard No.

BS ISO 10928:2024

Release Date

2024

Published By

British Standards Institution (BSI)  GB  /  BSI

Latest

BS ISO 10928:2024

Introduction

Analysis of the core content of the standard

BS ISO 10928:2024 provides two regression analysis methods for GRP piping systems:

Method type	Applicable scenarios	Data requirements	Key formulas
Method A (Covariance method)	Destructive test data (such as hoop tensile strength)	Allow skewed distribution r≥0.354(n=50)	y=a+b×lg(t)
Method B (Time variable regression)	Non-destructive testing (such as creep stiffness)	Requires normal distribution r≥0.301(n=72)	y=a+b×lg(t)

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Technology evolution and standard update

Main changes in the 2024 version:

• Delete the original Appendix BNon-linear relationship section (due to limited application scenarios)
• Correct the error in the 2×Bx_L coefficient in formula B.3
• Specify that 50 years (438,000 hours) is the maximum extrapolation time limit

Application case: Hoop strength test

When using Method A to analyze 10,000 hours of test data:

1. Calculated correlation coefficient r=0.938＞0.448(n=32)
2. Verification|T|=14.817＞t_v=2.042
3. Extrapolated 50-year strength value: 27.55MPa

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Implementation Recommendations

GRP pipe manufacturers should pay attention to:

Application scenarios	Analysis requirements	Output results
Product design	Mandatory use of Method A	Long-term strength benchmark value
Standard compliance verification	Method A+95%LPL	Comparison with standard limits
Performance statement	Method B polynomial fitting	Published long-term creep modulus

Key points of statistical verification

The standard provides two sets of verification data sets:

• Table 3: 32 sets of destructive test data (Method A verification)
• Table 5: 15 sets of creep test data (Method B verification)

The deviation between the calculated results and the standard example is required to be ≤0.1%