Overview
ISO/TS 26873:2010 is an international technical specification published by the International Organization for Standardization (ISO). It focuses on plastics pipes and fittings, specifically defining and providing construction procedures for reference lines. These reference lines serve as a generic representation of the creep rupture properties of thermoplastic pipes, which are critical for assessing their long-term strength and durability under internal pressure.
This document delivers a standardized method for drafting reference lines in a mathematical format, ensuring consistency and reliability in evaluating the performance of thermoplastic pipes used in various fluid conveyance systems.
Key Topics
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Reference Lines Definition: A mathematical description of stress rupture properties in thermoplastics, predicting the hoop strength of pipes with at least 97.5% confidence.
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Mathematical Model: Uses a four-parameter equation incorporating time to failure (hours), hoop stress (MPa), and temperature (Kelvin) to derive the reference lines. The formula accommodates two branches to represent brittle and ductile behavior.
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Construction Procedures:
- Regression Method: Analysis based on data sets from tests at minimum three temperatures with at least 10 K spacing, followed by vertical adjustment of the regression line to cover 97.5% of test points.
- Constructed Reference Lines: A 4-parameter model developed when regression is inapplicable.
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Scope & Applicability: Targets thermoplastic materials like PE (Polyethylene), PB (Polybutene), PE-X (Cross-linked polyethylene), PE-RT (Raised temperature resistant polyethylene), PP (Polypropylene), PVC-C (Chlorinated PVC), PVC-U (Unplasticized PVC), ABS, and PVDF, among others.
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Related ISO Standards: References to ISO 1167-1 and ISO 1167-2 for internal pressure testing and ISO 9080 for long-term hydrostatic strength determination, ensuring alignment with other test methodologies.
Applications
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Product Design & Specification: Enables accurate calculation of design stress values for thermoplastic pipes, critical in product standardization and safety assurances.
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Reliability Engineering: Facilitates the prediction of pipe lifespan under varying temperature and pressure conditions through standardized reference lines.
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Quality Control & Certification: Provides benchmark lines used in assessing conformity to international standards and ensuring product fitness for purpose.
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Industry Use Cases:
- Water supply and drainage systems
- Industrial fluid conveyance
- Hot and cold water installation piping
- Sewerage and pressure pipe systems
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Performance Evaluation: Supports interpolation and extrapolation for stress rupture properties and application of cumulative damage calculation methods such as Miner's rule (ISO 13760).
Related Standards
ISO/TS 26873:2010 complements a wide range of other ISO standards that specify reference lines and requirements for various thermoplastic materials and piping systems, including:
These related standards provide a comprehensive framework supporting the design, testing, and certification of thermoplastic piping systems worldwide.
Keywords: ISO/TS 26873:2010, plastics pipes, fittings, reference lines, thermoplastics, creep rupture properties, pipe strength, stress rupture, internal pressure, ISO standards, polypropylene (PP), polyethylene (PE), PVC, pipe durability, piping system standards, long-term strength, design stress calculation.