Overview
ISO 6358-2:2019/Amd 1:2026 is an international standard amendment published by the International Organization for Standardization (ISO). This amendment specifically addresses the evaluation of measurement uncertainty in the determination of flow-rate characteristics of pneumatic components using compressible fluids. It complements ISO 6358-2:2019, which defines alternative test methods for measuring flow-rate parameters in pneumatic fluid power systems.
This document is an essential resource for laboratories, manufacturers, and professionals involved in pneumatic fluid power, ensuring consistency, repeatability, and reliability in the assessment of flow characteristics. Given the vital role of accurate flow-rate data in design, quality assurance, and regulatory compliance, understanding measurement uncertainty is key for robust pneumatic systems.
Key Topics
- Measurement Uncertainty: Guidance on how to estimate and express the uncertainty in flow-rate measurement results, following international best practices, such as those outlined in ISO/IEC Guide 98-3 (GUM).
- Type A and Type B Uncertainty: Methods of uncertainty evaluation, including statistical analysis from repeated measurements (Type A) and data from calibration certificates, reference materials, or other sources (Type B).
- Combined Standard Uncertainty: Procedures for combining multiple sources of uncertainty to calculate total uncertainty according to the law of propagation of uncertainty.
- Critical Parameters: Focus on the uncertainty associated with key flow-rate characteristics-such as sonic conductance, critical back-pressure ratio, and subsonic index.
- Experimental Bias: Consideration and correction of systematic measurement errors, particularly those arising from tank volume and temperature variations during tests.
- Repeatability and Reproducibility: Use of established statistical methods for evaluating the consistency of test results across repeated and varied measurements.
- Pragmatic Approaches: Adapting test effort and methods based on the “fit for purpose” principle, ensuring efforts are balanced with user needs.
Applications
The application of ISO 6358-2:2019/Amd 1:2026 is crucial in various industrial and research contexts, including:
- Component Testing: Ensures accurate flow-rate characterisation of pneumatic valves, actuators, and related components.
- Quality Assurance: Assists manufacturers in certifying that their pneumatic products meet defined performance and safety requirements.
- Calibration Laboratories: Provides methodologies for robust estimation of measurement uncertainty, supporting traceable and comparable results.
- Regulatory Compliance: Supports adherence to international standards for pneumatic system testing, facilitating access to global markets.
- Research and Development: Enables detailed analysis and innovation in pneumatic technology by clarifying the reliability of flow-rate data.
Related Standards
For a comprehensive approach to pneumatic fluid power testing and measurement uncertainty, consider these related ISO standards:
- ISO 6358-1: Pneumatic fluid power - Determination of flow-rate characteristics of components using compressible fluids - Part 1: General rules and test methods for steady-state flow.
- ISO/IEC Guide 98-3 (GUM:1995): Guide to the Expression of Uncertainty in Measurement - Fundamental reference for evaluating and expressing uncertainty.
- ISO 5725-2: Accuracy (trueness and precision) of measurement methods and results - Part 2: Basic method for the determination of repeatability and reproducibility.
- ISO/TS 21748: Guidance for the use of repeatability, reproducibility, and trueness estimates.
ISO 6358-2:2019/Amd 1:2026 not only enhances consistency in pneumatic component testing, but also builds trust in test results across the pneumatic industry worldwide. For detailed procedures and mathematical expressions, consult the full ISO standard.
Open preview (PDF)Pneumatic fluid power — Determination of flow-rate characteristics of components using compressible fluids — Part 2: Alternative test methods — Amendment 1: Evaluation of measurement uncertainty